National Library of Energy BETA

Sample records for aerosol absorption absorption

  1. Light Absorption of Primary Organic Aerosol Paper Named ACS Editors...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Absorption of Primary Organic Aerosol Paper Named ACS Editors' Choice For original submission and image(s), see ARM Research Highlights http:www.arm.govsciencehighlights...

  2. Method and apparatus for aerosol particle absorption spectroscopy

    DOE Patents [OSTI]

    Campillo, Anthony J.; Lin, Horn-Bond

    1983-11-15

    A method and apparatus for determining the absorption spectra, and other properties, of aerosol particles. A heating beam source provides a beam of electromagnetic energy which is scanned through the region of the spectrum which is of interest. Particles exposed to the heating beam which have absorption bands within the band width of the heating beam absorb energy from the beam. The particles are also illuminated by light of a wave length such that the light is scattered by the particles. The absorption spectra of the particles can thus be determined from an analysis of the scattered light since the absorption of energy by the particles will affect the way the light is scattered. Preferably the heating beam is modulated to simplify the analysis of the scattered light. In one embodiment the heating beam is intensity modulated so that the scattered light will also be intensity modulated when the particles absorb energy. In another embodiment the heating beam passes through an interferometer and the scattered light reflects the Fourier Transform of the absorption spectra.

  3. Investigation of Absorption Properties of Submicron Aerosol in the Troposphere Over West Siberia

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Investigation of Absorption Properties of Submicron Aerosol in the Troposphere Over West Siberia M. V. Panchenko, V. S. Kozlov, and V. P. Shmargunov Institute of Atmospheric Optics Tomsk, Russia Introduction Improving radiative climate models for the cloudless atmosphere depends largely on the correct way to simulate single-scattering albedo of atmospheric aerosol. Solving this problem requires performing detailed experiments on the study of the aerosol absorption characteristics in the

  4. The impact of biogenic carbon emissions on aerosol absorption inMexico City

    SciTech Connect (OSTI)

    Marley, N; Gaffney, J; Tackett, M J; Sturchio, N; Hearty, L; Martinez, N; Hardy, K D; Machany-Rivera, A; Guilderson, T P; MacMillan, A; Steelman, K

    2009-02-24

    In order to determine the wavelength dependence of atmospheric aerosol absorption in the Mexico City area, the absorption angstrom exponents (AAEs) were calculated from aerosol absorption measurements at seven wavelengths obtained with a seven-channel aethalometer during two field campaigns, the Mexico City Metropolitan Area study in April 2003 (MCMA 2003) and the Megacity Initiative: Local and Global Research Observations in March 2006 (MILAGRO). The AAEs varied from 0.76 to 1.56 in 2003 and from 0.54 to 1.52 in 2006. The AAE values determined in the afternoon were consistently higher than the corresponding morning values, suggesting the photochemical formation of absorbing secondary organic aerosols (SOA) in the afternoon. The AAE values were compared to stable and radiocarbon isotopic measurements of aerosol samples collected at the same time to determine the sources of the aerosol carbon. The fraction of modern carbon (fM) in the aerosol samples, as determined from {sup 14}C analysis, showed that 70% of the carbonaceous aerosols in Mexico City were from modern sources, indicating a significant impact from biomass burning during both field campaigns. The {sup 13}C/{sup 12}C ratios of the aerosol samples illustrate the significant impact of Yucatan forest fires (C-3 plants) in 2003 and local grass fires (C-4 plants) at site T1 in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and calculated aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.

  5. Investigations of the Absorption Properties of Near-Ground Aerosol by the Methods of Optical-Acoustic Spectrometry and Diff...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Investigations of the Absorption Properties of Near-Ground Aerosol by the Methods of Optical-Acoustic Spectrometry and Diffuse Extinction V. S. Kozlov, M. V. Panchenko, A. B. Tikhomirov, and B. A. Tikhomirov Institute of Atmospheric Optics Tomsk, Russia Introduction Aerosol absorption is an important factor in the formation of non-selective radiation extinction in the visible wavelength range, and plays a great role in solving many radiative and climatic problems. The principal absorbing

  6. ABSORPTION ANALYZER

    DOE Patents [OSTI]

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  7. Absorption Cooling Basics

    Office of Energy Efficiency and Renewable Energy (EERE)

    Absorption coolers use heat rather than electricity as their energy source. Because natural gas is the most common heat source for absorption cooling, it is also referred to as gas-fired cooling.

  8. Residential Absorption Water Heater

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Residential Absorption Water Heater 2014 Building Technologies Office Peer Review Kyle ... Target MarketAudience: Residential gas water heating Key Partners: GE CRADA partner SRA ...

  9. Solar absorption surface panel

    DOE Patents [OSTI]

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  10. Continuous Light Absorption Photometer (CLAP) Final Campaign Report

    SciTech Connect (OSTI)

    Jefferson, Anne

    2014-05-01

    The Continuous Light Absorption Photometer (CLAP) measures the aerosol absorption of radiation at three visible wavelengths; 461, 522, and 653 nanometers (nm). Data from this measurement is used in radiative forcing calculations, atmospheric heating rates, and as a prediction of the amount of equivalent black carbon in atmospheric aerosol and in models of aerosol semi-direct forcing. Aerosol absorption measurements are essential to modeling the energy balance of the atmosphere.

  11. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  12. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  13. Soliton absorption spectroscopy

    SciTech Connect (OSTI)

    Kalashnikov, V. L.; Sorokin, E.

    2010-03-15

    We analyze optical soliton propagation in the presence of weak absorption lines with much narrower linewidths as compared to the soliton spectrum width by using a perturbation analysis technique based on an integral representation in the spectral domain. The stable soliton acquires a spectral modulation that follows the associated index of refraction of the absorber. The model can be applied to ordinary soliton propagation and to an absorber inside a passively mode-locked laser. In the latter case, a comparison with water vapor absorption in a femtosecond Cr:ZnSe laser yields a very good agreement with experiment. Compared to the conventional absorption measurements in a cell of the same length, the signal is increased by an order of magnitude. The obtained analytical expressions allow further improvement in the sensitivity and spectroscopic accuracy, which makes soliton absorption spectroscopy a promising measurement technique.

  14. Optical absorption measurement system

    DOE Patents [OSTI]

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  15. Solar selective absorption coatings

    DOE Patents [OSTI]

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  16. Solar selective absorption coatings

    DOE Patents [OSTI]

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  17. Seven-effect absorption refrigeration

    DOE Patents [OSTI]

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  18. Seven-effect absorption refrigeration

    DOE Patents [OSTI]

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  19. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  20. ARM - Measurement - Aerosol absorption

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    External Instruments OMI : Ozone Monitoring Instrument TOMS : Total Ozone Mapping ... OMI : Ozone Monitoring Instrument Datastreams OMI : Ozone Monitoring Instrument TOMS : ...

  1. Ultraviolet absorption hygrometer

    DOE Patents [OSTI]

    Gersh, Michael E.; Bien, Fritz; Bernstein, Lawrence S.

    1986-01-01

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined.

  2. Ultraviolet absorption hygrometer

    DOE Patents [OSTI]

    Gersh, M.E.; Bien, F.; Bernstein, L.S.

    1986-12-09

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined. 5 figs.

  3. SMB, X-ray Absorption Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Absorption Spectroscopy X-ray Absorption Spectroscopy X-ray absorption spectroscopy (XAS) is a well-established technique for simultaneous local geometric and electronic structure...

  4. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments [OSTI]

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  5. Gas-absorption process

    DOE Patents [OSTI]

    Stephenson, Michael J.; Eby, Robert S.

    1978-01-01

    This invention is an improved gas-absorption process for the recovery of a desired component from a feed-gas mixture containing the same. In the preferred form of the invention, the process operations are conducted in a closed-loop system including a gas-liquid contacting column having upper, intermediate, and lower contacting zones. A liquid absorbent for the desired component is circulated through the loop, being passed downwardly through the column, regenerated, withdrawn from a reboiler, and then recycled to the column. A novel technique is employed to concentrate the desired component in a narrow section of the intermediate zone. This technique comprises maintaining the temperature of the liquid-phase input to the intermediate zone at a sufficiently lower value than that of the gas-phase input to the zone to effect condensation of a major part of the absorbent-vapor upflow to the section. This establishes a steep temperature gradient in the section. The stripping factors below this section are selected to ensure that virtually all of the gases in the downflowing absorbent from the section are desorbed. The stripping factors above the section are selected to ensure re-dissolution of the desired component but not the less-soluble diluent gases. As a result, a peak concentration of the desired component is established in the section, and gas rich in that component can be withdrawn therefrom. The new process provides important advantages. The chief advantage is that the process operations can be conducted in a single column in which the contacting zones operate at essentially the same pressure.

  6. The rediscovery of absorption chillers

    SciTech Connect (OSTI)

    Katzel, J.

    1992-04-23

    Absorption chillers are back - and for two very good reasons: they are environmentally sound and, in many cases, economically attractive. One factor fueling this resurgence is the outlook for natural gas, the energy source of most absorption systems. Deregulation has spurred exploration, and forecasts indicate an abundant supply and relatively low prices through 2050. Threats of global warming and depletion of the ozone layer also are forces driving the absorption chiller market. Being a good corporate citizen today means minimizing or eliminating the use of chlorofluorocarbons (CFCs), the basis of many refrigerants used in mechanical chillers. Even as chemical and chiller manufacturers alike work to develop substitute refrigerants, the perfect alternative has yet to be found. Absorption units are free of these problems, a benefit that appeals to many people.

  7. Absorption Heat Pumps | Department of Energy

    Energy Savers [EERE]

    Heat Pump Systems Absorption Heat Pumps Absorption Heat Pumps Absorption heat pumps are ... As in a standard heat pump, the refrigerant (in this case, ammonia) is condensed in one ...

  8. Mechanical properties and energy absorption characteristics of...

    Office of Scientific and Technical Information (OSTI)

    Mechanical properties and energy absorption characteristics of a polyurethane foam Citation Details In-Document Search Title: Mechanical properties and energy absorption ...

  9. Absorption-heat-pump system

    DOE Patents [OSTI]

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  10. Transient absorption spectroscopy of laser shocked explosives

    SciTech Connect (OSTI)

    Mcgrane, Shawn D; Dang, Nhan C; Whitley, Von H; Bolome, Cindy A; Moore, D S

    2010-01-01

    Transient absorption spectra from 390-890 nm of laser shocked RDX, PETN, sapphire, and polyvinylnitrate (PVN) at sub-nanosecond time scales are reported. RDX shows a nearly linear increase in absorption with time after shock at {approx}23 GPa. PETN is similar, but with smaller total absorption. A broad visible absorption in sapphire begins nearly immediately upon shock loading but does not build over time. PVN exhibits thin film interference in the absorption spectra along with increased absorption with time. The absorptions in RDX and PETN are suggested to originate in chemical reactions happening on picosecond time scales at these shock stresses, although further diagnostics are required to prove this interpretation.

  11. Absorption Heat Pumps | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Heat Pump Systems » Absorption Heat Pumps Absorption Heat Pumps Absorption heat pumps are essentially air-source heat pumps driven not by electricity, but by a heat source such as natural gas, propane, solar-heated water, or geothermal-heated water. Because natural gas is the most common heat source for absorption heat pumps, they are also referred to as gas-fired heat pumps. There are also absorption (or gas-fired) coolers available that work on the same principle. Unlike some absorption heat

  12. Photodetector with enhanced light absorption

    DOE Patents [OSTI]

    Kane, James

    1985-01-01

    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  13. GAX absorption cycle design process

    SciTech Connect (OSTI)

    Priedeman, D.K.; Christensen, R.N.

    1999-07-01

    This paper presents an absorption system design process that relies on computer simulations that are validated by experimental findings. An ammonia-water absorption heat pump cycle at 3 refrigeration tons (RT) and chillers at 3.3 RT and 5 RT (10.5 kW, 11.6 kW, and 17.6 kW) were initially modeled and then built and tested. The experimental results were used to calibrate both the cycle simulation and the component simulations, yielding computer design routines that could accurately predict component and cycle performance. Each system was a generator-absorber heat exchange (GAX) cycle, and all were sized for residential and light commercial use, where very little absorption equipment is currently used. The specific findings of the 5 RT (17.6 kW) chiller are presented. Modeling incorporated a heat loss from the gas-fired generator and pressure drops in both the evaporator and absorber. Simulation results and experimental findings agreed closely and validated the modeling method and simulation software.

  14. Purge needs in absorption chillers

    SciTech Connect (OSTI)

    Murray, J.G. )

    1993-10-01

    Absorption chillers are regaining a significant share of large tonnage chiller sales, such as they had 20 years ago. Gas-fired chillers are now available that have a base energy (ultimate fuel usage) consumption rate per ton comparable to that in electric units. Effective purging in an absorption chiller is an absolute necessity to achieve the low chilled water temperature needed for dehumidification and to fully benefit from the energy savings offered by double-effect cycles. Although the purge system is usually not shown on the typical cycle schematic, its proper functioning is a key requirement for satisfactory machine operation. This article discusses the effect of noncondensible (N/C) gases on the absorption cooling process and the basics of purge systems. In addition, the article discusses the rationale for the important design step of selecting the location of the N/C probe, and discusses purge systems applicable to the direct-fired, double-effect machines now entering the marketplace.

  15. Absorption Cooling Basics | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    Absorption coolers use heat rather than electricity as their energy source. Because natural gas is the most common heat source for absorption cooling, it is also referred to as...

  16. Advanced regenerative absorption refrigeration cycles

    DOE Patents [OSTI]

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  17. NEUTRON ABSORPTION AND SHIELDING DEVICE

    DOE Patents [OSTI]

    Axelrad, I.R.

    1960-06-21

    A neutron absorption and shielding device is described which is adapted for mounting in a radiation shielding wall surrounding a radioactive area through which instrumentation leads and the like may safely pass without permitting gamma or neutron radiation to pass to the exterior. The shielding device comprises a container having at least one nonrectilinear tube or passageway means extending therethrough, which is adapted to contain instrumentation leads or the like, a layer of a substance capable of absorbing gamma rays, and a solid resinous composition adapted to attenuate fast-moving neutrons and capture slow- moving or thermal neutrons.

  18. Olefin recovery via chemical absorption

    SciTech Connect (OSTI)

    Barchas, R.

    1998-06-01

    The recovery of fight olefins in petrochemical plants has generally been accomplished through cryogenic distillation, a process which is very capital and energy intensive. In an effort to simplify the recovery process and reduce its cost, BP Chemicals has developed a chemical absorption technology based on an aqueous silver nitrate solution. Stone & Webster is now marketing, licensing, and engineering the technology. The process is commercially ready for recovering olefins from olefin derivative plant vent gases, such as vents from polyethylene, polypropylene, ethylene oxide, and synthetic ethanol units. The process can also be used to debottleneck C{sub 2} or C{sub 3} splinters, or to improve olefin product purity. This paper presents the olefin recovery imp technology, discusses its applications, and presents economics for the recovery of ethylene and propylene.

  19. Backscatter absorption gas imaging system

    DOE Patents [OSTI]

    McRae, T.G. Jr.

    A video imaging system for detecting hazardous gas leaks. Visual displays of invisible gas clouds are produced by radiation augmentation of the field of view of an imaging device by radiation corresponding to an absorption line of the gas to be detected. The field of view of an imager is irradiated by a laser. The imager receives both backscattered laser light and background radiation. When a detectable gas is present, the backscattered laser light is highly attenuated, producing a region of contrast or shadow on the image. A flying spot imaging system is utilized to synchronously irradiate and scan the area to lower laser power requirements. The imager signal is processed to produce a video display.

  20. Backscatter absorption gas imaging system

    DOE Patents [OSTI]

    McRae, Jr., Thomas G.

    1985-01-01

    A video imaging system for detecting hazardous gas leaks. Visual displays of invisible gas clouds are produced by radiation augmentation of the field of view of an imaging device by radiation corresponding to an absorption line of the gas to be detected. The field of view of an imager is irradiated by a laser. The imager receives both backscattered laser light and background radiation. When a detectable gas is present, the backscattered laser light is highly attenuated, producing a region of contrast or shadow on the image. A flying spot imaging system is utilized to synchronously irradiate and scan the area to lower laser power requirements. The imager signal is processed to produce a video display.

  1. Neutron scattering and absorption properties

    SciTech Connect (OSTI)

    Holden, N.E.

    1993-12-01

    The Table in this report presents an evaluated set of values for the experimental quantities, which characterize the properties for scattering and absorption of neutrons. The neutron cross section is given for room temperature neutrons, 20.43{degree}C, corresponds to a thermal neutron energy of 0.0253 electron volts (eV) or a neutron velocity of 2200 meters/second. The neutron resonance integral is defined over the energy range from 0.5 eV to 0.1 {times} 10{sup 6} eV, or 0.1 MeV. A list of the major references used is given below. The literature cutoff data is October 1993. Uncertainties are given in parentheses. Parentheses with two or more numbers indicate values to the excited states(s) and to the ground state of the product nucleus.

  2. Advanced Low Temperature Absorption Chiller Module Integrated...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Data Center - Presentation by Exergy Partners Corp., June 2011 Advanced Low Temperature Absorption Chiller Module Integrated with a CHP System at a Distributed Data Center - ...

  3. Absorption Heat Pump Basics | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Heat Pump Basics Absorption Heat Pump Basics August 19, 2013 - 11:11am Addthis Absorption heat pumps are essentially air-source heat pumps driven not by electricity, but by a heat source such as natural gas, propane, solar-heated water, or geothermal-heated water. Because natural gas is the most common heat source for absorption heat pumps, they are also referred to as gas-fired heat pumps. There are also absorption coolers available that work on the same principal, but are not reversible and

  4. Cavity-Enhanced Transient Absorption Spectroscopy: Ultrafast...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cavity-Enhanced Transient Absorption Spectroscopy: Ultrafast Spectroscopy goes Ultra-Sensitive Wednesday, November 11, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A...

  5. Compact Absorption Chiller - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Energy Efficiency Building Energy Efficiency Find More Like This Return to Search Compact Absorption Chiller Pacific Northwest National Laboratory Contact PNNL About This...

  6. Direct and quantitative broadband absorptance spectroscopy with...

    Office of Scientific and Technical Information (OSTI)

    Patent: Direct and quantitative broadband absorptance spectroscopy with multilayer ... DOE Contract Number: FG02-02ER45977 Resource Type: Patent Research Org: Massachusetts ...

  7. Commercial Absorption Heat Pump Water Heater

    Broader source: Energy.gov (indexed) [DOE]

    Absorption Heat Pump Water Heater 2016 Building Technologies Office Peer Review Patrick ... The target market is the hospital, hotel and full service restaurant gas hot water heating ...

  8. Pressure dependence of Hexanitrostilbene Raman/ electronic absorption...

    Office of Scientific and Technical Information (OSTI)

    Hexanitrostilbene Raman electronic absorption spectra to validate DFT EOS. Citation Details In-Document Search Title: Pressure dependence of Hexanitrostilbene Raman electronic ...

  9. Pressure dependence of Hexanitrostilbene Raman/ electronic absorption...

    Office of Scientific and Technical Information (OSTI)

    in hydrodynamic simulations of the performance of HNS, we have measured the Raman and electronic absorption spectra of this material under static pressure in a diamond anvil cell. ...

  10. Combining Feedback Absorption Spectroscopy, Amplified Resonance...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Automotive Emissions Combining Feedback Absorption Spectroscopy, Amplified Resonance and Low Pressure Sampling for the Measurement of Nitrogen-Containing Compounds in Automotive ...

  11. Transient simulation of absorption machines

    SciTech Connect (OSTI)

    Anand, D.K.; Allen, R.W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steady-state value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  12. Transient simulation of absorption machines

    SciTech Connect (OSTI)

    Anand, D.K.; Allen, R.W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steadystate value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  13. Gas-fueled absorption heat pump

    SciTech Connect (OSTI)

    Florette, M.; Peuportier, B.

    1982-01-01

    To determine the feasibility of using an absorption heat pump for residential space heating, French investigators are studying both theoretically and experimentally, the performance of the absorption cycle in terms of its efficiency and suitability to space-heating conditions. A 10-kW pilot unit is supplying data on design criteria, heat-exchange fluid selection, and heat and mass balances.

  14. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect (OSTI)

    Xue, Y.

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the {mu}M level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  15. Absorption of carbonyl sulfide in aqueous methyldiethanolamine

    SciTech Connect (OSTI)

    Al-Ghawas, H.A.; Ruiz-Ibanez, G.; Sandall, O.C. (Dept. of Chemical and Nuclear Engineering, Univ. of California, Santa Barbara, CA (US))

    1988-01-01

    The absorption of carbonyl sulfide in aqueous methyldiethanolamine (MDEA) was studied over a range of temperatures and MDEA concentrations. MDEA is commonly used for selective absorption of hydrogen sulfide in the presence of carbon dioxide. However, sulfur in the form of COS may also be present and it is necessary that estimates of absorption rates of this compound be made. The objective of this study is to determine the physiochemical properties needed to predict COS absorption rates in aqueous MDEA. Free gas solubility and the diffusivity of COS in MDEA solutions were measured over the temperature range 15 to 40{sup 0}C for MDEA concentrations up to 30 weight per cent using the nitrous oxide analogy method. Solubilities were measured volumetrically in an equilibrium cell and diffusivities were measured using a laminar liquid jet absorber. The kinetics of the reaction between COS and MDEA were studied by measuring absorption rates in a single wetted-sphere absorber.

  16. Absorption chillers: Technology for the future

    SciTech Connect (OSTI)

    Garland, P.W.; Garland, R.W.

    1997-12-31

    In an era of heightened awareness of energy efficiency and the associated environmental impacts, many industries worldwide are exploring ``environmentally friendly`` technologies that provide equivalent or improved performance while reducing or eliminating harmful side-effects. The refrigeration and air-conditioning industry, due to its reliance on CFCs and HCFCs, has invested in research in alternatives to the industry standard vapor compression machines. One alternative technology with great promise is chemical absorption. Absorption chillers offer comparable refrigeration output with reduced SO{sub 2}, CO{sub 2}, and NO{sub x} emissions. Absorption chillers do not use CFCs or HCFCs, refrigerants that contribute to ozone depletion and global warming. Additionally, gas-fired absorption chillers can save significant amounts in energy costs when used in combination with a vapor compression chiller in a hybrid system. The hybrid system can take advantage of the comparatively low price of natural gas (per unit ton) and rely on the high performance of vapor compression when electricity prices are lower. The purpose of this article is to provide an introduction for those new to absorption technology as well as a discussion of selected high efficiency cycles, a discussion on the technology of coupling absorption with vapor compression systems to form a hybrid system, and the environmental impacts of absorption.

  17. Absorption Heat Pumps | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    an ammonia-water absorption cycle to provide heating and cooling. As in a standard heat pump, the refrigerant (in this case, ammonia) is condensed in one coil to release its...

  18. Variable effect desorber-resorber absorption cycle

    DOE Patents [OSTI]

    Biermann, Wendell J.

    1985-01-01

    An absorption refrigeration system has an intermediate temperature desorber-resorber pair. A valve between the desorber-resorber pair is modulated to control the capacity for load matching.

  19. Triple-effect absorption chiller cycles

    SciTech Connect (OSTI)

    DeVault, R.C. ); Grossman, G. )

    1992-01-01

    Gas-fired absorption chillers are widely used for air-conditioning buildings. Even the highest efficiency double-effect absorption chillers used more primary energy for air-conditioning buildings than the better electric chillers. Two different triple-effect absorption chiller cycles are capable of substantial performance improvement over equivalent double-effect cycles. One cycle uses two condensers and two absorbers to achieve the triple effect.'' A second cycle, the Double-Condenser Coupled Triple-Effect, uses three condensers as well as a third condenser subcooler (which exchanges heat with the lowest temperature first-effect generator). These triple-effect absorption cycles have the potential to be as energy efficient (on a primary fuel basis) as the best electric chillers. 19 refs.

  20. Absorption chillers: Part of the solution

    SciTech Connect (OSTI)

    Occhionero, A.J. ); Hughes, P.J. ); Reid, E.A. )

    1991-01-01

    Acid rain, ozone depletion, global warming, and implementation economics are considered as they relate to the advisability of expanding the application of absorption chillers. Introductory and background information are provided to put the discussion in the proper context. Then all four issues are discussed separately as they relate to absorption chillers. Acid rain and ozone depletion concerns, and implementation economics, are found to support the expanded use of absorption chillers. The global warming concern is found to be more of a gray area, but the areas of benefit correspond well with the conditions of greatest economic advantage. All things considered, absorption chillers are believed to be part of the environmental and economic solution. It is further believed that integrated resource planning (IRP) processes that consider electric and gas technologies on an equal footing would come to the same conclusion for many regions of the United States. 9 refs., 3 tabs.

  1. Triple-effect absorption chiller cycles

    SciTech Connect (OSTI)

    DeVault, R.C.; Grossman, G.

    1992-06-01

    Gas-fired absorption chillers are widely used for air-conditioning buildings. Even the highest efficiency double-effect absorption chillers used more primary energy for air-conditioning buildings than the better electric chillers. Two different triple-effect absorption chiller cycles are capable of substantial performance improvement over equivalent double-effect cycles. One cycle uses two condensers and two absorbers to achieve the ``triple effect.`` A second cycle, the Double-Condenser Coupled Triple-Effect, uses three condensers as well as a third condenser subcooler (which exchanges heat with the lowest temperature first-effect generator). These triple-effect absorption cycles have the potential to be as energy efficient (on a primary fuel basis) as the best electric chillers. 19 refs.

  2. An Analysis of Cloud Absorption During

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Analysis of Cloud Absorption During ARESE II (Spring 2000) D. M. Powell, R. T. Marchand, and T. P. Ackerman Pacific Northwest National Laboratory Richland, Washington Introduction In early spring 2000, Atmospheric Radiation Measurement (ARM) Program researchers held an intensive operational period (IOP) at the ARM Southern Great Plains (SGP) site. This IOP had several objectives, one of which was to was to re-evaluate (with redundant measurements wherever possible) absorption by low-level

  3. Posters Long-Pathlength Infrared Absorption Measurements

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 Posters Long-Pathlength Infrared Absorption Measurements in the 8- to 14-µm Atmospheric Window: Self-Broadening Coefficient Data T. J. Kulp (a) and J. Shinn Geophysics and Environmental Research Program Lawrence Livermore National Laboratory Livermore, California Introduction The accurate characterization of the latent infrared (IR) absorption in the atmospheric window regions continues to be an area of research interest for the global climate modeling community. In the window between 8 and

  4. Effects of backlight structure on absorption experiments (Journal...

    Office of Scientific and Technical Information (OSTI)

    Quantitative Spectroscopy and Radiative Transfer; Journal Volume: 99 Research Org: ... Language: English Subject: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; ABSORPTION ...

  5. Water-lithium bromide double-effect absorption cooling analysis...

    Office of Scientific and Technical Information (OSTI)

    Water-lithium bromide double-effect absorption cooling analysis Citation Details In-Document Search Title: Water-lithium bromide double-effect absorption cooling analysis You ...

  6. Effects of hydrogen/deuterium absorption on the magnetic properties...

    Office of Scientific and Technical Information (OSTI)

    Effects of hydrogendeuterium absorption on the magnetic properties of CoPd multilayers Citation Details In-Document Search Title: Effects of hydrogendeuterium absorption on the...

  7. Absorption and emission properties of photonic crystals and metamateri...

    Office of Scientific and Technical Information (OSTI)

    ThesisDissertation: Absorption and emission properties of photonic crystals and metamaterials Citation Details In-Document Search Title: Absorption and emission properties of ...

  8. Dataset used to improve liquid water absorption models in the...

    Office of Scientific and Technical Information (OSTI)

    Dataset used to improve liquid water absorption models in the microwave Title: Dataset used to improve liquid water absorption models in the microwave Two datasets, one a ...

  9. XUV Absorption by Solid Density Aluminum (Journal Article) |...

    Office of Scientific and Technical Information (OSTI)

    XUV Absorption by Solid Density Aluminum Citation Details In-Document Search Title: XUV Absorption by Solid Density Aluminum An inverse bremsstrahlung model for plasmas and simple ...

  10. Enhanced Absorption in 2D Materials Via Fano- Resonant Photonic...

    Office of Scientific and Technical Information (OSTI)

    Enhanced Absorption in 2D Materials Via Fano- Resonant Photonic Crystals Citation Details In-Document Search Title: Enhanced Absorption in 2D Materials Via Fano- Resonant Photonic ...

  11. Origins of optical absorption characteristics of Cu2+ complexes...

    Office of Scientific and Technical Information (OSTI)

    Origins of optical absorption characteristics of Cu2+ complexes in solutions Citation Details In-Document Search Title: Origins of optical absorption characteristics of Cu2+ ...

  12. Absorption Spectra and Plotting Exciton Wavefunctions BerkeleyGW...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Hands on Session 5: Converging Absorption Spectra and Plotting Exciton Wavefunctions BerkeleyGW Workshop 11232013 Diana Qiu Converging Absorption General Parameters: K-grid...

  13. High resolution absorption spectroscopy of exploding wire plasmas...

    Office of Scientific and Technical Information (OSTI)

    Published Article: High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal Title: High resolution absorption ...

  14. Absorption Heat Pump Water Heater - 2013 Peer Review | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Absorption Heat Pump Water Heater - 2013 Peer Review Absorption Heat Pump Water Heater - 2013 Peer Review Emerging Technologies Project for the 2013 Building Technologies Office's ...

  15. Radiance Research Particle Soot/Absorption Photometer Instrument...

    Office of Scientific and Technical Information (OSTI)

    Radiance Research Particle SootAbsorption Photometer Instrument Handbook Citation Details In-Document Search Title: Radiance Research Particle SootAbsorption Photometer ...

  16. CO2 Capture by Absorption with Potassium Carbonate (Technical...

    Office of Scientific and Technical Information (OSTI)

    CO2 Capture by Absorption with Potassium Carbonate Citation Details In-Document Search Title: CO2 Capture by Absorption with Potassium Carbonate You are accessing a document ...

  17. CO2 Capture by Absorption with Potassium Carbonate (Technical...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: CO2 Capture by Absorption with Potassium Carbonate Citation Details In-Document Search Title: CO2 Capture by Absorption with Potassium Carbonate You are ...

  18. Integrated vacuum absorption steam cycle gas separation (Patent...

    Office of Scientific and Technical Information (OSTI)

    vacuum absorption steam cycle gas separation Citation Details In-Document Search Title: Integrated vacuum absorption steam cycle gas separation Methods and systems for separating ...

  19. Spectroscopic study of low-temperature hydrogen absorption in...

    Office of Scientific and Technical Information (OSTI)

    Spectroscopic study of low-temperature hydrogen absorption in palladium Citation Details In-Document Search Title: Spectroscopic study of low-temperature hydrogen absorption in...

  20. Simulating a 4-effect absorption chiller

    SciTech Connect (OSTI)

    Grossman, G.; Zaltash, A.; Adcock, P.W.; DeVault, R.C.

    1995-06-01

    Absorption chillers are heat-operated refrigeration machines that operate on one of the earliest known principles of refrigeration. Current absorption chillers typically use either steam or a gas-fired burner as the energy source. All current gas-fired absorption cooling systems are based on the well known single-effect or double-effect cycles. To further improve utilization of the high temperature heat available from natural gas, a variety of triple-effect cycles have been proposed and are being developed that are capable of substantial performance improvement over equivalent double-effect cycles. This article describes a study that investigated the possibility of even further improving utilization of the high temperature heat available from natural gas combustion. During the study, performance simulation was conducted for a 4-effect lithium bromide/water cycle. From an environmental perspective, absorption chillers provide several benefits. They use absorption pairs (such as lithium bromide/water) as the working fluids, rather than chlorofluorocarbons or hydrochlorofluorocarbons, which contribute to ozone depletion and global warming.

  1. Plasmon absorption modulator systems and methods

    DOE Patents [OSTI]

    Kekatpure, Rohan Deodatta; Davids, Paul

    2014-07-15

    Plasmon absorption modulator systems and methods are disclosed. A plasmon absorption modulator system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and a metal layer formed on a top surface of the stack of quantum well layers. A method for modulating plasmonic current includes enabling propagation of the plasmonic current along a metal layer, and applying a voltage across the stack of quantum well layers to cause absorption of a portion of energy of the plasmonic current by the stack of quantum well layers. A metamaterial switching system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and at least one metamaterial structure formed on a top surface of the stack of quantum well layers.

  2. Nanofibrous membrane-based absorption refrigeration system

    SciTech Connect (OSTI)

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  3. Laser isotope separation by multiple photon absorption

    DOE Patents [OSTI]

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1987-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

  4. Laser isotope separation by multiple photon absorption

    DOE Patents [OSTI]

    Robinson, C. Paul; Rockwood, Stephen D.; Jensen, Reed J.; Lyman, John L.; Aldridge, III, Jack P.

    1977-01-01

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, in the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

  5. Laser isotope separation by multiple photon absorption

    DOE Patents [OSTI]

    Robinson, C.P.; Rockwood, S.D.; Jensen, R.J.; Lyman, J.L.; Aldridge, J.P. III.

    1987-04-07

    Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO[sub 2] laser light may be used to highly enrich [sup 34]S in natural SF[sub 6] and [sup 11]B in natural BCl[sub 3]. 8 figs.

  6. Direct fired absorption machine flue gas recuperator

    DOE Patents [OSTI]

    Reimann, Robert C.; Root, Richard A.

    1985-01-01

    A recuperator which recovers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine. The recuperator includes a housing with liquid flowing therethrough, the liquid being in direct contact with the combustion gas for increasing the effectiveness of the heat transfer between the gas and the liquid.

  7. Coupled dual loop absorption heat pump

    DOE Patents [OSTI]

    Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.

    1985-01-01

    A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

  8. Corrosion inhibitor for aqueous ammonia absorption system

    DOE Patents [OSTI]

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  9. Corrosion inhibitor for aqueous ammonia absorption system

    DOE Patents [OSTI]

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  10. Absorption machine with desorber-resorber

    DOE Patents [OSTI]

    Biermann, Wendell J.

    1985-01-01

    An absorption refrigeration system utilizing a low temperature desorber and intermediate temperature resorber. The system operates at three temperatures and three pressures to increase the efficiency of the system and is capable of utilizing a lower generator temperature than previously used.

  11. Absorption of Thermal Neutrons in Uranium

    DOE R&D Accomplishments [OSTI]

    Creutz, E. C.; Wilson, R. R.; Wigner, E. P.

    1941-09-26

    A knowledge of the absorption processes for neutrons in uranium is important for planning a chain reaction experiment. The absorption of thermal neutrons in uranium and uranium oxide has been studied. Neutrons from the cyclotron were slowed down by passage through a graphite block. A uranium or uranium oxide sphere was placed at various positions in the block. The neutron intensity at different points in the sphere and in the graphite was measured by observing the activity induced in detectors or uranium oxide or manganese. It was found that both the fission activity in the uranium oxide and the activity induced in manganese was affected by non-thermal neutrons. An experimental correction for such effects was made by making measurements with the detectors surrounded by cadmium. After such corrections the results from three methods of procedure with the uranium oxide detectors and from the manganese detectors were consistent to within a few per cent.

  12. Polaron absorption in amorphous tungsten oxide films

    SciTech Connect (OSTI)

    Berggren, Lars; Azens, Andris; Niklasson, Gunnar A.

    2001-08-15

    Amorphous thin films of tungsten oxide were deposited by sputtering onto glass substrates covered by conductive indium--tin oxide. The density and stoichiometry were determined by Rutherford backscattering spectrometry. Lithium ions were intercalated electrochemically into the films. The optical reflectance and transmittance were measured in the wavelength range from 0.3 to 2.5 {mu}m, at a number of intercalation levels. The polaron absorption peak becomes more symmetric and shifts to higher energies until an intercalation level of 0.25 to 0.3 Li{sup +}/W, where a saturation occurs. The shape of the polaron peak is in very good agreement with the theory of Bryksin [Fiz. Tverd. Tela 24, 1110 (1982)]. Within this model, the shift of the absorption peak is interpreted as an increase in the Fermi level of the material as more Li ions are inserted. {copyright} 2001 American Institute of Physics.

  13. Integrated vacuum absorption steam cycle gas separation

    SciTech Connect (OSTI)

    Chen, Shiaguo; Lu, Yonggi; Rostam-Abadi, Massoud

    2011-11-22

    Methods and systems for separating a targeted gas from a gas stream emitted from a power plant. The gas stream is brought into contact with an absorption solution to preferentially absorb the targeted gas to be separated from the gas stream so that an absorbed gas is present within the absorption solution. This provides a gas-rich solution, which is introduced into a stripper. Low pressure exhaust steam from a low pressure steam turbine of the power plant is injected into the stripper with the gas-rich solution. The absorbed gas from the gas-rich solution is stripped in the stripper using the injected low pressure steam to provide a gas stream containing the targeted gas. The stripper is at or near vacuum. Water vapor in a gas stream from the stripper is condensed in a condenser operating at a pressure lower than the stripper to concentrate the targeted gas. Condensed water is separated from the concentrated targeted gas.

  14. Particle Soot Absorption Photometer Instrument Handbook

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    6 Particle Soot Absorption Photometer Handbook SR Springston March 2016 DISCLAIMER This report was prepared as an account of work sponsored by the U.S. Government. Neither the United States nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned

  15. A New Model for Liquid Water Absorption

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Model for Liquid Water Absorption For original submission and image(s), see ARM Research Highlights http://www.arm.gov/science/highlights/ Research Highlight Liquid water path (LWP) is a critical measurement for a wide range of atmospheric studies, as the amount of liquid in a cloud is critical to understanding many cloud processes. For example, the radiative impact of the cloud (in both the longwave and shortwave portions of the spectrum) depends heavily on the LWP. Thus, the Atmospheric

  16. Radiation absorption properties of different plaster samples

    SciTech Connect (OSTI)

    Akkurt, Iskender; Guenoglu, Kadir; Mavi, Betuel; K Latin-Small-Letter-Dotless-I l Latin-Small-Letter-Dotless-I ncarslan, Semsettin; Seven, Aysun

    2012-09-06

    Although the plaster is one of the oldest known synthetic building materials, nowadays, it is used as interior coating of walls and ceilings of buildings. Thus measuring its radiation shielding properties is vital. For this purpose, radiation absorption properties of different plaster samples in this study. The measurements have been performed using gamma spectrometer system which connected to 3'' Multiplication-Sign 3''NaI (TI) detector.

  17. WATER-LITHIUM BROMIDE DOUBLE-EFFECT ABSORPTION COOLING ANALYSIS

    Office of Scientific and Technical Information (OSTI)

    WATER-LITHIUM BROMIDE DOUBLE-EFFECT ABSORPTION COOLING ANALYSIS Gary C . V l i e t , ... i e n t simulation of the double-effect, water-1 ithium bromide absorption cooling ...

  18. Triple effect absorption chiller utilizing two refrigeration circuits

    SciTech Connect (OSTI)

    DeVault, R.C.

    1988-03-22

    This patent describes a heat absorption method for an absorption chiller. It comprises: providing a firs absorption system circuit for operation within a first temperature range, providing a second absorption system circuit for operation within a second temperature range; heat exchanging refrigerant and absorber solution; thermal communication with an external heat load. This patent describes a heat absorption apparatus for use as an absorption chiller. It includes: a first absorption system circuit for operation within a first temperature range; a second absorption system circuit for operation within a second temperature range which has a lower maximum temperature relative to the first temperature range; the first circuit having generator means, condenser means, evaporator means, and absorber means operatively connected together; the second circuit having generator means condenser means, evaporator means, and absorber means operative connected together; and the first circuit condenser means and the first circuit absorber means being in heat exchange communication with the second circuit generator means.

  19. Effect of Various Impurities on the Hydrogen Absorption on SAES...

    Office of Environmental Management (EM)

    Effect of Various Impurities on the Hydrogen Absorption on SAES ST198 Effect of Various Impurities on the Hydrogen Absorption on SAES ST198 Presentation from the 36th Tritium Focus ...

  20. Attosecond Electron Wave-Packet Interference Observed by Transient Absorption

    SciTech Connect (OSTI)

    Holler, M.; Schapper, F.; Gallmann, L.; Keller, U.

    2011-03-25

    We perform attosecond time-resolved transient absorption spectroscopy around the first ionization threshold of helium and observe rapid oscillations of the absorption of the individual harmonics as a function of time delay with respect to a superimposed, moderately strong infrared laser field. The phase relation between the absorption modulation of individual harmonics gives direct evidence for the interference of transiently bound electronic wave packets as the mechanism behind the absorption modulation.

  1. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE (Technical...

    Office of Scientific and Technical Information (OSTI)

    Subject: 54 ENVIRONMENTAL SCIENCES; CARBON DIOXIDE; ABSORPTION; SORPTIVE PROPERTIES; POTASSIUM CARBONATES; THERMODYNAMIC MODEL; VAPOR PRESSURE; AIR POLLUTION CONTROL Word Cloud ...

  2. CO2 Capture by Absorption with Potassium Carbonate (Technical...

    Office of Scientific and Technical Information (OSTI)

    ... Subject: 54 ENVIRONMENTAL SCIENCES; CARBON DIOXIDE; ABSORPTION; POTASSIUM CARBONATES; SORPTIVE PROPERTIES; AMINES; MATERIALS RECOVERY; AIR POLLUTION CONTROL; MATHEMATICAL MODELS ...

  3. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE (Technical...

    Office of Scientific and Technical Information (OSTI)

    Subject: 54 ENVIRONMENTAL SCIENCES; ABSORPTION; HEAT EXCHANGERS; PILOT PLANTS; POTASSIUM CARBONATES; THERMODYNAMICS; VAPOR PRESSURE; CARBON DIOXIDE; AIR POLLUTION CONTROL; SORPTIVE ...

  4. Split-flow regeneration in absorptive air separation

    DOE Patents [OSTI]

    Weimer, R.F.

    1987-11-24

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs. 4 figs.

  5. Split-flow regeneration in absorptive air separation

    DOE Patents [OSTI]

    Weimer, Robert F.

    1987-01-01

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs.

  6. Continuous Light Absorption Photometer (CLAP) Final Campaign...

    Office of Scientific and Technical Information (OSTI)

    black carbon in atmospheric aerosol and in models of aerosol semi-direct forcing. ... Sponsoring Org: USDOE Office of Science (SC) Country of Publication: United States ...

  7. 44th Annual Anomalous Absorption Conference

    SciTech Connect (OSTI)

    Beg, Farhat

    2014-03-03

    Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded

  8. Thermal model of solar absorption HVAC systems

    SciTech Connect (OSTI)

    Bergquam, J.B.; Brezner, J.M.

    1995-11-01

    This paper presents a thermal model that describes the performance of solar absorption HVAC systems. The model considers the collector array, the building cooling and heating loads, the absorption chiller and the high temperature storage. Heat losses from the storage tank and piping are included in the model. All of the results presented in the paper are for an array of flat plate solar collectors with black chrome (selective surface) absorber plates. The collector efficiency equation is used to calculate the useful heat output from the array. The storage is modeled as a non-stratified tank with polyurethane foam insulation. The system is assumed to operate continuously providing air conditioning during the cooling season, space heating during the winter and hot water throughout the year. The amount of heat required to drive the chiller is determined from the coefficient of performance of the absorption cycle. Results are presented for a typical COP of 0.7. The cooling capacity of the chiller is a function of storage (generator) temperature. The nominal value is 190 F (88 C) and the range of values considered is 180 F (82 C) to 210 F (99 C). Typical building cooling and heating loads are determined as a function of ambient conditions. Performance results are presented for Sacramento, CA and Washington, D.C. The model described in the paper makes use of National Solar Radiation Data Base (NSRDB) data and results are presented for these two locations. The uncertainties in the NSRDB are estimated to be in a range of 6% to 9%. This is a significant improvement over previously available data. The model makes it possible to predict the performance of solar HVAC systems and calculate quantities such as solar fraction, storage temperature, heat losses and parasitic power for every hour of the period for which data are available.

  9. Laser dynamics with excited-state absorption

    SciTech Connect (OSTI)

    Sanchez, F.; Kellou, A.

    1997-01-01

    The dynamics of a laser with excited-state absorption at the lasing wavelength is theoretically studied. The model is based on the rate equations for a four-level system. The stationary state is analytically calculated, permitting both the investigation of the laser characteristics and linear stability analysis. The latter shows that, in some conditions, the steady state is not stable in a particular range of pumping rates. However, a stable solution is restored for sufficiently high pumping rates. Stable self-pulsing solutions are obtained by numerical integration of the coupled equations. Also, the transient regimes are numerically analyzed. {copyright} 1997 Optical Society of America.

  10. Distributed Bragg Reflectors With Reduced Optical Absorption

    DOE Patents [OSTI]

    Klem, John F.

    2005-08-16

    A new class of distributed Bragg reflectors has been developed. These distributed Bragg reflectors comprise interlayers positioned between sets of high-index and low-index quarter-wave plates. The presence of these interlayers is to reduce photon absorption resulting from spatially indirect photon-assisted electronic transitions between the high-index and low-index quarter wave plates. The distributed Bragg reflectors have applications for use in vertical-cavity surface-emitting lasers for use at 1.55 .mu.m and at other wavelengths of interest.

  11. Improved self-absorption correction for extended x-ray absorption fine-structure measurements

    SciTech Connect (OSTI)

    Booth, C.H.; Bridges, F.

    2003-06-04

    Extended x-ray absorption fine-structure (EXAFS) data collected in the fluorescence mode are susceptible to an apparent amplitude reduction due to the self-absorption of the fluorescing photon by the sample before it reaches a detector. Previous treatments have made the simplifying assumption that the effect of the EXAFS on the correction term is negligible, and that the samples are in the thick limit. We present a nearly exact treatment that can be applied for any sample thickness or concentration, and retains the EXAFS oscillations in the correction term.

  12. Dilution cycle control for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C.

    1984-01-01

    A dilution cycle control system for an absorption refrigeration system is disclosed. The control system includes a time delay relay for sensing shutdown of the absorption refrigeration system and for generating a control signal only after expiration of a preselected time period measured from the sensed shutdown of the absorption refrigeration system, during which the absorption refrigeration system is not restarted. A dilution cycle for the absorption refrigeration system is initiated in response to generation of a control signal by the time delay relay. This control system is particularly suitable for use with an absorption refrigeration system which is frequently cycled on and off since the time delay provided by the control system prevents needless dilution of the absorption refrigeration system when the system is turned off for only a short period of time and then is turned back on.

  13. Absorption of solar radiation in broken clouds

    SciTech Connect (OSTI)

    Zuev, V.E.; Titov, G.A.; Zhuravleva, T.B.

    1996-04-01

    It is recognized now that the plane-parallel model unsatisfactorily describes the transfer of radiation through broken clouds and that, consequently, the radiation codes of general circulation models (GCMs) must be refined. However, before any refinement in a GCM code is made, it is necessary to investigate the dependence of radiative characteristics on the effects caused by the random geometry of cloud fields. Such studies for mean fluxes of downwelling and upwelling solar radiation in the visible and near-infrared (IR) spectral range were performed by Zuev et al. In this work, we investigate the mean spectral and integrated absorption of solar radiation by broken clouds (in what follows, the term {open_quotes}mean{close_quotes} will be implied but not used, for convenience). To evaluate the potential effect of stochastic geometry, we will compare the absorption by cumulus (0.5 {le} {gamma} {le} 2) to that by equivalent stratus ({gamma} <<1) clouds; here {gamma} = H/D, H is the cloud layer thickness and D the characteristic horizontal cloud size. The equivalent stratus clouds differ from cumulus only in the aspect ratio {gamma}, all the other parameters coinciding.

  14. Residential solar-absorption chiller thermal dynamics

    SciTech Connect (OSTI)

    Guertin, J.M.; Wood, B.D.; McNeill, B.W.

    1981-03-01

    Research is reported on the transient performance of a commercial residential 3 ton lithium bromide-water absorption chiller designed for solar firing. Emphasis was placed on separating the chiller response from that of the entire test facility so that its transient response could solely be observed and quantified. It was found that the entire system time response and thermal capacitance has a major impact on performance degradation due to transient operation. Tests run to ascertain computer algorithms which simulate system isolated chiller performance, revealed processes hitherto undocumented. Transient operation is simulated by three distinct algorithms associated with the three phases of chiller operation. The first phase is start up time. It was revealed during testing that the time required to reach steady state performance values, when the chiller was turned on, was a linear function of steady state water supply temperatures. The second phase is quasi steady state performance. Test facility's performance compared favorably with the manufacturer's published data. The third phase is the extra capacity produced during spin down. Spin down occurs when the hot water supply pump is turned off while the other system pumps remain operating for a few minutes, thus allowing extra chiller capacity to be realized. The computer algorithms were used to generate plots which show the operational surface of an isolated absorption chiller subjected to off design and transient operation.

  15. Solar absorption cooling plant in Seville

    SciTech Connect (OSTI)

    Bermejo, Pablo; Pino, Francisco Javier; Rosa, Felipe

    2010-08-15

    A solar/gas cooling plant at the Engineering School of Seville (Spain) was tested during the period 2008-2009. The system is composed of a double-effect LiBr + water absorption chiller of 174 kW nominal cooling capacity, powered by: (1) a pressurized hot water flow delivered by mean of a 352 m{sup 2} solar field of a linear concentrating Fresnel collector and (2) a direct-fired natural gas burner. The objective of the project is to indentify design improvements for future plants and to serve as a guideline. We focused our attention on the solar collector size and dirtiness, climatology, piping heat losses, operation control and coupling between solar collector and chiller. The daily average Fresnel collector efficiency was 0.35 with a maximum of 0.4. The absorption chiller operated with a daily average coefficient of performance of 1.1-1.25, where the solar energy represented the 75% of generator's total heat input, and the solar cooling ratio (quotient between useful cooling and insolation incident on the solar field) was 0.44. (author)

  16. Hydroxide absorption heat pumps with spray absorber

    SciTech Connect (OSTI)

    Summerer, F.; Alefeld, G.; Zeigler, F.; Riesch, P.

    1996-11-01

    The absorber is one of the most expensive components of an absorption heat pump or chiller, respectively. In order to reduce the cost of a heat exchanger, much effort is invested into searching for additives for heat transfer enhancement. Another way to reduce heat exchanger cost, especially for machines with low capacities, is to use an adiabatic spray absorber. The basic principles of the spray absorber is to perform heat and mass transfer separated from each other in two different components. In this way the heat can be rejected effectively in a liquid-liquid heat exchanger, whereas the mass transfer occurs subsequently in a simple vessel. The spray technique can not only save heat exchanger cost in conventional absorption systems working with water and lithium bromide, it also allows the use of quite different working fluids such as hydroxides, which have lower heat transfer coefficients in falling films. Moreover, the separated heat transfer can easily be performed in a liquid-to-air heat exchanger. Hence it is obvious to use hydroxides that allow for a high temperature lift for building an air-cooled chiller with spray absorber. In this presentation theoretical and experimental investigations of the spray absorber as well as the setup will be described. Finally, possible applications will be outlined.

  17. Light absorption from particulate impurities in snow and ice determined by spectrophotometric analysis of filters

    SciTech Connect (OSTI)

    Grenfell, Thomas C.; Doherty, Sarah J.; Clarke, Antony D.; Warren, Stephen G.

    2011-05-10

    Light absorption by particulate impurities in snow and ice can affect the surface albedo and is important for the climate. The absorption properties of these particles can be determined by collecting and melting snow samples and extracting the particulate material by filtration of the meltwater. This paper describes the optical design and testing of a new instrument to measure the absorption spectrum from 400 to 750 nm wavelength of the particles collected on filters using an ''integrating-sandwich'' configuration. The measured absorption is shown to be unaffected by scattering of light from the deposited particulates. A set of calibration standards is used to derive an upper limit for the concentration of black carbon (BC) in the snow. The wavelength dependence of the absorption spectra from 450 to 600 nm is used to calculate an absorption Angstrom exponent for the aerosol. This exponent is used to estimate the actual BC concentration in the snow samples as well as the relative contributions of BC and non-BC constituents to the absorption of solar radiation integrated over the wavelength band 300 to 750 nm.

  18. Gas separation using ultrasound and light absorption

    DOE Patents [OSTI]

    Sinha, Dipen N.

    2012-07-31

    An apparatus and method for separating a chosen gas from a mixture of gases having no moving parts and utilizing no chemical processing is described. The separation of particulates from fluid carriers thereof has been observed using ultrasound. In a similar manner, molecular species may be separated from carrier species. It is also known that light-induced drift may separate light-absorbing species from carrier species. Therefore, the combination of temporally pulsed absorption of light with ultrasonic concentration is expected to significantly increase the efficiency of separation by ultrasonic concentration alone. Additionally, breaking the spatial symmetry of a cylindrical acoustic concentrator decreases the spatial distribution of the concentrated particles, and increases the concentration efficiency.

  19. Counterflow absorber for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C.

    1984-01-01

    An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

  20. Spray generators for absorption refrigeration systems

    DOE Patents [OSTI]

    Sibley, Howard W.

    1979-06-19

    A spray generator for an absorption refrigeration system that includes a heat exchanger comprised of a multiplicity of variably spaced heat exchange tubes. The tubes are spaced close together near the top of the heat exchanger and spaced more widely apart near the bottom of the heat exchanger. Dilute absorbent solution is sprayed down through the heat exchanger. The close nesting of the tubes in the top portion of the heat exchanger retards liquid flow and aids heating of the solution. The wide spacing of the tubes in the lower section of the heat exchanger facilitate vapor flow out of the heat exchanger and eliminates liquid "blow-off". The top tubes are covered by a baffle to prevent the liquid solution from splashing out of the heat exchanger off of these top tubes.

  1. Enhanced light absorption of solar cells and photodetectors by diffraction

    DOE Patents [OSTI]

    Zaidi, Saleem H.; Gee, James M.

    2005-02-22

    Enhanced light absorption of solar cells and photodetectors by diffraction is described. Triangular, rectangular, and blazed subwavelength periodic structures are shown to improve performance of solar cells. Surface reflection can be tailored for either broadband, or narrow-band spectral absorption. Enhanced absorption is achieved by efficient optical coupling into obliquely propagating transmitted diffraction orders. Subwavelength one-dimensional structures are designed for polarization-dependent, wavelength-selective absorption in solar cells and photodetectors, while two-dimensional structures are designed for polarization-independent, wavelength-selective absorption therein. Suitable one and two-dimensional subwavelength periodic structures can also be designed for broadband spectral absorption in solar cells and photodetectors. If reactive ion etching (RIE) processes are used to form the grating, RIE-induced surface damage in subwavelength structures can be repaired by forming junctions using ion implantation methods. RIE-induced surface damage can also be removed by post RIE wet-chemical etching treatments.

  2. Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption

    Office of Environmental Management (EM)

    Process (TCAP) | Department of Energy Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) Presentation from the 32nd Tritium Focus Group Meeting held in Germantown, Maryland on April 23-25, 2013. Advances in Hydrogen Isotope Separation Using Thermal Cycling Absorption Process (TCAP) (1.74 MB) More Documents & Publications A New Hydrogen Processing Demonstration System Initial

  3. Commercial Absorption Heat Pump Water Heater | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Absorption Heat Pump Water Heater Commercial Absorption Heat Pump Water Heater Credit: Oak Ridge National Laboratory Credit: Oak Ridge National Laboratory Lead Performer: Oak Ridge National Laboratory - Oak Ridge, TN Partner: A.O. Smith Inc. - Milwaukee, WI DOE Funding: $2,000,000 Cost Share: Provided by CRADA partners Project Term: October 1, 2013 - September 30, 2016 Project Objective The objective of this project is to develop a gas-fired absorption heat pump water heater for the commercial

  4. The Future of Absorption Technology in America: A Critical Look...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    The Future of Absorption Technology in America: A Critical Look at the Impact of Building, ... for CHP Applications, April 2005 Review of Thermally Activated Technologies, July ...

  5. Flexible flux plane simulations of parasitic absorption in nanoplasmon...

    Office of Scientific and Technical Information (OSTI)

    thin-film silicon solar cells Prev Next Title: Flexible flux plane simulations of parasitic absorption in nanoplasmonic thin-film silicon solar cells Authors: Chung, H. ...

  6. Light Trapping, Absorption and Solar Energy Harvesting by Artificial...

    Office of Scientific and Technical Information (OSTI)

    Energy Harvesting by Artificial Materials Citation Details In-Document Search Title: Light Trapping, Absorption and Solar Energy Harvesting by Artificial Materials We provide ...

  7. CO2 Capture from Flue Gas by Phase Transitional Absorption

    SciTech Connect (OSTI)

    Liang Hu

    2009-06-30

    A novel absorption process called Phase Transitional Absorption was invented. What is the Phase Transitional Absorption? Phase Transitional Absorption is a two or multi phase absorption system, CO{sub 2} rich phase and CO{sub 2} lean phase. During Absorption, CO{sub 2} is accumulated in CO{sub 2} rich phase. After separating the two phases, CO{sub 2} rich phase is forward to regeneration. After regeneration, the regenerated CO{sub 2} rich phase combines CO{sub 2} lean phase to form absorbent again to complete the cycle. The advantage for Phase Transitional Absorption is obvious, significantly saving on regeneration energy. Because CO{sub 2} lean phase was separated before regeneration, only CO{sub 2} rich phase was forward to regeneration. The absorption system we developed has the features of high absorption rate, high loading and working capacity, low corrosion, low regeneration heat, no toxic to environment, etc. The process evaluation shows that our process is able to save 80% energy cost by comparing with MEA process.

  8. X-ray transient absorption and picosecond IR spectroscopy of...

    Office of Scientific and Technical Information (OSTI)

    X-ray transient absorption and picosecond IR spectroscopy of fulvalene(tetracarbonyl)diruthenium on photoexcitation Citation Details In-Document Search Title: X-ray transient ...

  9. ITP Industrial Distributed Energy: The Future of Absorption Technology...

    Broader source: Energy.gov (indexed) [DOE]

    1 Ferdinand Carr Several factors have influenced absorption chiller sales since then. Natural gas prices, as well as, fuel availability concerns and governmental policies...

  10. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE (Technical...

    Office of Scientific and Technical Information (OSTI)

    Subject: 54 ENVIRONMENTAL SCIENCES; CARBON DIOXIDE; ABSORPTION; ACID NEUTRALIZING CAPACITY; DESORPTION; POTASSIUM CARBONATES; AMINES; AIR POLLUTION CONTROL; FLUE GAS Word Cloud ...

  11. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE (Technical...

    Office of Scientific and Technical Information (OSTI)

    Subject: 54 ENVIRONMENTAL SCIENCES; ABSORPTION; PERFORMANCE; POTASSIUM CARBONATES; CHEMICAL REACTION KINETICS; CARBON DIOXIDE; AIR POLLUTION CONTROL; AMINES Word Cloud More Like ...

  12. Residential Absorption Heat Pump Water Heater | Department of...

    Broader source: Energy.gov (indexed) [DOE]

    Oak Ridge National Laboratory (ORNL) is developing and promoting the market introduction of a residential absorption heat pump water heater that would use 40% less energy annually ...

  13. Kinetic performance of CO2 absorption into a potassium carbonate...

    Office of Scientific and Technical Information (OSTI)

    Title: Kinetic performance of CO2 absorption into a potassium carbonate solution ... Type: Publisher's Accepted Manuscript Journal Name: Chemical Engineering Journal (Print) ...

  14. Measuring fast electron spectra and laser absorption in relativistic...

    Office of Scientific and Technical Information (OSTI)

    Measuring fast electron spectra and laser absorption in relativistic laser-solid interactions using differential bremsstrahlung photon detectors Citation Details In-Document Search ...

  15. Quantitative infrared absorption cross sections of isoprene for...

    Office of Scientific and Technical Information (OSTI)

    Quantitative infrared absorption cross sections of isoprene for atmospheric measurements ... and other oxygenated organics, yet little quantitative IR data exists for isoprene. ...

  16. Perfect electromagnetic absorption at one-atom-thick scale

    SciTech Connect (OSTI)

    Li, Sucheng; Duan, Qian; Li, Shuo; Yin, Qiang; Lu, Weixin; Li, Liang; Hou, Bo; Gu, Bangming; Wen, Weijia

    2015-11-02

    We experimentally demonstrate that perfect electromagnetic absorption can be realized in the one-atom thick graphene. Employing coherent illumination in the waveguide system, the absorbance of the unpatterned graphene monolayer is observed to be greater than 94% over the microwave X-band, 7–13 GHz, and to achieve a full absorption, >99% in experiment, at ∼8.3 GHz. In addition, the absorption characteristic manifests equivalently a wide range of incident angle. The experimental results agree very well with the theoretical calculations. Our work accomplishes the broadband, wide-angle, high-performance absorption in the thinnest material with simple configuration.

  17. Permeation absorption sampler with multiple detection

    DOE Patents [OSTI]

    Zaromb, Solomon

    1990-01-01

    A system for detecting analytes in air or aqueous systems includes a permeation absorption preconcentrator sampler for the analytes and analyte detectors. The preconcentrator has an inner fluid-permeable container into which a charge of analyte-sorbing liquid is intermittently injected, and a fluid-impermeable outer container. The sample is passed through the outer container and around the inner container for trapping and preconcentrating the analyte in the sorbing liquid. The analyte can be detected photometrically by injecting with the sorbing material a reagent which reacts with the analyte to produce a characteristic color or fluorescence which is detected by illuminating the contents of the inner container with a light source and measuring the absorbed or emitted light, or by producing a characteristic chemiluminescence which can be detected by a suitable light sensor. The analyte can also be detected amperometrically. Multiple inner containers may be provided into which a plurality of sorbing liquids are respectively introduced for simultaneously detecting different analytes. Baffles may be provided in the outer container. A calibration technique is disclosed.

  18. Absorption media for irreversibly gettering thionyl chloride

    DOE Patents [OSTI]

    Buffleben, George; Goods, Steven H.; Shepodd, Timothy; Wheeler, David R.; Whinnery, Jr., LeRoy

    2002-01-01

    Thionyl chloride is a hazardous and reactive chemical used as the liquid cathode in commercial primary batteries. Contrary to previous thinking, ASZM-TEDA.RTM. carbon (Calgon Corporation) reversibly absorbs thionyl chloride. Thus, several candidate materials were examined as irreversible getters for thionyl chloride. The capacity, rate and effect of temperature were also explored. A wide variety of likely materials were investigated through screening experiments focusing on the degree of heat generated by the reaction as well as the material absorption capacity and irreversibility, in order to help narrow the group of possible getter choices. More thorough, quantitative measurements were performed on promising materials. The best performing getter was a mixture of ZnO and ASZM-TEDA.RTM. carbon. In this example, the ZnO reacts with thionyl chloride to form ZnCl.sub.2 and SO.sub.2. The SO.sub.2 is then irreversibly gettered by ASZM-TEDA.RTM. carbon. This combination of ZnO and carbon has a high capacity, is irreversible and functions effectively above -20.degree. C.

  19. Cost reduction in absorption chillers: Phase 2

    SciTech Connect (OSTI)

    Leigh, R.W.

    1989-02-01

    A research program at Brookhaven National Laboratory (BNL) has addressed the possibility of dramatically lowering the first costs of absorption chillers through lowered material intensity and the use of lower cost materials, primarily in the heat exchangers which make up the bulk of the operating components of these systems. This must be done while retaining the best performance characteristics available today, a gross design point coefficient of performance (COP) of 1.3 and a net design (seasonal) average COP of 1.0 (0.90) in a directly fired, double effect unit. We have investigated several possible routes to these goals, and here report on these findings, focusing on the areas that appear most promising. The candidate technologies include the use of polymer film heat exchangers in several applications, the use of thin strips of new, corrosion resistant alloys to replace thicker, less impervious metals in applications exposed to gas flames, and copper or cupro-nickel foils in contact with system water. The use of such materials is only possible in the context of new heat exchanger and system designs, which are also discussed. To lend focus, we have concentrated on a directly fired double effect system providing capacity only. If successful, these techniques will also find wide applicability in heat pumps, cogeneration systems, solar cooling, heat recovery and chemical process heat transfer. 46 refs., 24 figs., 22 tabs.

  20. Triple effect absorption chiller utilizing two refrigeration circuits

    DOE Patents [OSTI]

    DeVault, Robert C.

    1988-01-01

    A triple effect absorption method and apparatus having a high coefficient of performance. Two single effect absorption circuits are combined with heat exchange occurring between a condenser and absorber of a high temperature circuit, and a generator of a low temperature circuit. The evaporators of both the high and low temperature circuits provide cooling to an external heat load.

  1. Heavy absorption chillers: The Tortoise technology that can win

    SciTech Connect (OSTI)

    Irwin, F.E.

    1995-06-01

    Why has Absorption taken over 200 years to become a viable technology and secondarily what is the long term potential for heavy absorption technology? A third interesting question may be as some knowledgeable people in the North America industry have professed, is there a Window of Opportunity which was presented by the electric vapor compressor refrigerant issue which will be the last chance for absorption? Of course we know that absorption is not a new technology in 1994. It is however being rediscovered in many parts of the world by specifiers and engineers who are otherwise totally familiar with HVAC systems technology. As has been well documented in Japan, absorption heavy systems have been dominant for some time to the point that over 90% of the new units installed in the heavy systems category are absorption. Further by now 50% of the installed heavy systems tonnage in the country are absorption chillers. It did not take the electric vapor compressor refrigerant issue to make this huge market for absorption and there aren`t too many people in the HVAC business in Japan that view absorption as the {open_quotes}Tortoise technology.{close_quotes} If we only understood what the drivers were in Japan to create this absorption market then perhaps we could understand and possibly predict the long term potential for the technology in other markets of the world. We could actually go to work and look for markets that mirror the prevailing conditions in Japan. There will be those amongst us who will tell you that Japan is a unique market in almost every product category and most certainly with respect to heavy chiller systems.

  2. Molecular shock response of explosives: electronic absorption spectroscopy

    SciTech Connect (OSTI)

    Mcgrne, Shawn D; Moore, David S; Whitley, Von H; Bolme, Cindy A; Eakins, Daniel E

    2009-01-01

    Electronic absorption spectroscopy in the range 400-800 nm was coupled to ultrafast laser generated shocks to begin addressing the question of the extent to which electronic excitations are involved in shock induced reactions. Data are presented on shocked polymethylmethacrylate (PMMA) thin films and single crystal pentaerythritol tetranitrate (PETN). Shocked PMMA exhibited thin film interference effects from the shock front. Shocked PETN exhibited interference from the shock front as well as broadband increased absorption. Relation to shock initiation hypotheses and the need for time dependent absorption data (future experiments) is briefly discussed.

  3. Overview of Resources for Geothermal Absorption Cooling for Buildings

    SciTech Connect (OSTI)

    Liu, Xiaobing; Gluesenkamp, Kyle R; Mehdizadeh Momen, Ayyoub

    2015-06-01

    This report summarizes the results of a literature review in three areas: available low-temperature/coproduced geothermal resources in the United States, energy use for space conditioning in commercial buildings, and state of the art of geothermal absorption cooling.

  4. ARM - Instrument - psap-particle-soot-absorption-photometer

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    govInstrumentspsap-particle-soot-absorption-photometer Documentation Comments? We would love to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Instrument :...

  5. Use Low-Grade Waste Steam to Power Absorption Chillers

    SciTech Connect (OSTI)

    Not Available

    2006-01-01

    This revised ITP tip sheet on waste steam to power absorption chillers provides how-to advice for improving the system using low-cost, proven practices and technologies.

  6. Collision--induced absorption in dense atmospheres of cool stars

    SciTech Connect (OSTI)

    Borysow, Aleksandra; Joergensen, Uffe Graae

    1999-04-01

    In the atmosphere of the Sun the major interaction between the matter and the radiation is through light absorption by ions (predominantly the negative ion of hydrogen atoms), neutral atoms and a small amount of polar molecules. The majority of stars in the universe are, however, cooler and denser than our Sun, and for a large fraction of these, the above absorption processes are very weak. Here, collision-induced absorption (CIA) becomes the dominant opacity source. The radiation is absorbed during very short mutual passages ('collisions') of two non-polar molecules (and/or atoms), while their electric charge distributions are temporarily distorted which gives rise to a transient dipole moment. We present here a review of the present-day knowledge about the impact of collision-induced absorption processes on the structure and the spectrum of such stars.

  7. Modelling aging effects on a thermal cycling absorption process column

    SciTech Connect (OSTI)

    Laquerbe, C.; Contreras, S.; Demoment, J.

    2008-07-15

    Palladium coated on alumina is used in hydrogen separation systems operated at CEA/Valduc, and more particularly in Thermal Cycling Absorption Process columns. With such materials, tritium decay is known to induce aging effects which have direct side effects on hydrogen isotopes absorption isotherms. Furthermore in a TCAP column, aging occurs in an heterogeneous way. The possible impacts of these intrinsic material evolutions on the separation performances are investigated here through a numerical approach. (authors)

  8. Advanced Low Temperature Absorption Chiller Module Integrated with a CHP

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    System at a Distributed Data Center - Presentation by Exergy Partners Corp., June 2011 | Department of Energy Low Temperature Absorption Chiller Module Integrated with a CHP System at a Distributed Data Center - Presentation by Exergy Partners Corp., June 2011 Advanced Low Temperature Absorption Chiller Module Integrated with a CHP System at a Distributed Data Center - Presentation by Exergy Partners Corp., June 2011 Presentation on Develop & Demonstrate an Advanced Low Temp Heat

  9. Near-infrared free carrier absorption in heavily doped silicon

    SciTech Connect (OSTI)

    Baker-Finch, Simeon C.; McIntosh, Keith R.; Yan, Di; Fong, Kean Chern; Kho, Teng C.

    2014-08-14

    Free carrier absorption in heavily doped silicon can have a significant impact on devices operating in the infrared. In the near infrared, the free carrier absorption process can compete with band to band absorption processes, thereby reducing the number of available photons to optoelectronic devices such as solar cells. In this work, we fabricate 18 heavily doped regions by phosphorus and boron diffusion into planar polished silicon wafers; the simple sample structure facilitates accurate and precise measurement of the free carrier absorptance. We measure and model reflectance and transmittance dispersion to arrive at a parameterisation for the free carrier absorption coefficient that applies in the wavelength range between 1000 and 1500 nm, and the range of dopant densities between ∼10{sup 18} and 3 × 10{sup 20} cm{sup −3}. Our measurements indicate that previously published parameterisations underestimate the free carrier absorptance in phosphorus diffusions. On the other hand, published parameterisations are generally consistent with our measurements and model for boron diffusions. Our new model is the first to be assigned uncertainty and is well-suited to routine device analysis.

  10. Quasi-static energy absorption of hollow microlattice structures

    SciTech Connect (OSTI)

    Liu, YL; Schaedler, TA; Jacobsen, AJ; Chen, X

    2014-12-01

    We present a comprehensive modeling and numerical study focusing on the energy quasi-static crushing behavior and energy absorption characteristics of hollow tube microlattice structures. The peak stress and effective plateau stress of the hollow microlattice structures are deduced for different geometrical parameters which gives volume and mass densities of energy absorption, D-v and D-m, scale with the relative density, (rho) over bar, as D-v similar to (rho) over bar (1) (5) and D-m similar to (rho) over bar (0 5), respectively, fitting very well to the experimental results of both 60 degrees inclined and 90 degrees predominately microlattices. Then the strategies for energy absorption enhancement are proposed for the engineering design of microlattice structures. By introducing a gradient in the thickness or radius of the lattice members, the buckle propagation can be modulated resulting in an increase in energy absorption density that can exceed 40%. Liquid filler is another approach to improve energy absorption by strengthening the microtruss via circumference expansion, and the gain may be over 100% in terms of volume density. Insight into the correlations between microlattice architecture and energy absorption performance combined with the high degree of architecture control paves the way for designing high performance microlattice structures for a range of impact and impulse mitigation applications for vehicles and structures. (C) 2014 Elsevier Ltd. All rights reserved.

  11. Carbon Dioxide Separation from Flue Gas by Phase Enhanced Absorption

    SciTech Connect (OSTI)

    Tim Fout

    2007-06-30

    A new process, phase enhanced absorption, was invented. The method is carried out in an absorber, where a liquid carrier (aqueous solution), an organic mixture (or organic compound), and a gas mixture containing a gas to be absorbed are introduced from an inlet. Since the organic mixture is immiscible or at least partially immiscible with the liquid carrier, the organic mixture forms a layer or small parcels between the liquid carrier and the gas mixture. The organic mixture in the absorber improves mass transfer efficiency of the system and increases the absorption rate of the gas. The organic mixture serves as a transportation media. The gas is finally accumulated in the liquid carrier as in a conventional gas-liquid absorption system. The presence of the organic layer does not hinder the regeneration of the liquid carrier or recovery of the gas because the organic layer is removed by a settler after the absorption process is completed. In another aspect, the system exhibited increased gas-liquid separation efficiency, thereby reducing the costs of operation and maintenance. Our study focused on the search of the organic layer or transportation layer to enhance the absorption rate of carbon dioxide. The following systems were studied, (1) CO{sub 2}-water system and CO{sub 2}-water-organic layer system; (2) CO{sub 2}-Potassium Carbonate aqueous solution system and CO{sub 2}-Potassium Carbonate aqueous solution-organic layer system. CO{sub 2}-water and CO{sub 2}-Potassium Carbonate systems are the traditional gas-liquid absorption processes. The CO{sub 2}-water-organic layer and CO{sub 2}-Potassium Carbonate-organic layer systems are the novel absorption processes, phase enhanced absorption. As we mentioned early, organic layer is used for the increase of absorption rate, and plays the role of transportation of CO{sub 2}. Our study showed that the absorption rate can be increased by adding the organic layer. However, the enhanced factor is highly depended on the

  12. X-ray absorption spectroscopy study of Gd[superscript 3+]-loaded...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: X-ray absorption spectroscopy study of Gdsuperscript 3+-loaded ultra-short carbon nanotubes Citation Details In-Document Search Title: X-ray absorption ...

  13. High throughput liquid absorption preconcentrator sampling instrument

    DOE Patents [OSTI]

    Zaromb, S.; Bozen, R.M.

    1992-12-22

    A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis. 12 figs.

  14. High throughput liquid absorption preconcentrator sampling instrument

    DOE Patents [OSTI]

    Zaromb, Solomon (Hinsdale, IL); Bozen, Ralph M. (Hattiesburg, MS)

    1992-01-01

    A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

  15. Development of an Ionic-Liquid Absorption Heat Pump

    SciTech Connect (OSTI)

    Holcomb, Don

    2011-03-29

    Solar Fueled Products (SFP) is developing an innovative ionic-liquid absorption heat pump (ILAHP). The development of an ILAHP is extremely significant, as it could result in annual savings of more than 190 billion kW h of electrical energy and $19 billion. This absorption cooler uses about 75 percent less electricity than conventional cooling and heating units. The ILAHP also has significant environmental sustainability benefits, due to reduced CO2 emissions. Phase I established the feasibility and showed the economic viability of an ILAHP with these key accomplishments: • Used the breakthrough capabilities provided by ionic liquids which overcome the key difficulties of the common absorption coolers. • Showed that the theoretical thermodynamic performance of an ILAHP is similar to existing absorption-cooling systems. • Established that the half-effect absorption cycle reduces the peak generator temperature, improving collector efficiency and reducing collector area. • Component testing demonstrated that the most critical components, absorber and generator, operate well with conventional heat exchangers. • Showed the economic viability of an ILAHP. The significant energy savings, sustainability benefits, and economic viability are compelling reasons to continue the ILAHP development.

  16. ARM - Field Campaign - Carbonaceous Aerosol and Radiation Effects...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photo-Acoustic Aerosol Light Absorption and Scattering Campaign Links ARM Data Discovery Browse Data Related Campaigns Carbonaceous Aerosol and Radiative Effects Study (CARES) ...

  17. Direct and quantitative broadband absorptance spectroscopy with multilayer cantilever probes

    DOE Patents [OSTI]

    Hsu, Wei-Chun; Tong, Jonathan Kien-Kwok; Liao, Bolin; Chen, Gang

    2015-04-21

    A system for measuring the absorption spectrum of a sample is provided that includes a broadband light source that produces broadband light defined within a range of an absorptance spectrum. An interferometer modulates the intensity of the broadband light source for a range of modulation frequencies. A bi-layer cantilever probe arm is thermally connected to a sample arm having at most two layers of materials. The broadband light modulated by the interferometer is directed towards the sample and absorbed by the sample and converted into heat, which causes a temperature rise and bending of the bi-layer cantilever probe arm. A detector mechanism measures and records the deflection of the probe arm so as to obtain the absorptance spectrum of the sample.

  18. NMR microscopy of heavy metal absorption in calcium alginate beads

    SciTech Connect (OSTI)

    Nestle, N.; Kimmich, R.

    1996-01-01

    In recent years, heavy metal uptake by biopolymer gels, such as Cal-Alginate or chitosan, has been studied by various methods. This is of interest because such materials might be an alternative to synthetical ion-exchange resins in the treatment of industrial waste waters. Most of the work done in this field consisted of studies of equilibrium absorption of different heavy metal ions with dependence on various experimental parameters. In some publications, the kinetics of absorption were studied, too. However, no experiments on the spatial distribution of heavy metals during the absorption process are known to us. Using Cu as an example, it is demonstrated in this article that NMR microscopy is an appropriate tool for such studies. By the method presented here, it is possible to monitor the spatial distribution of heavy metal ions with a time resolution of about 5 min and a spatial resolution of 100 {mu}m or even better. 14 refs., 10 figs.

  19. Backscatter absorption gas imaging systems and light sources therefore

    DOE Patents [OSTI]

    Kulp, Thomas Jan; Kliner, Dahv A. V.; Sommers, Ricky; Goers, Uta-Barbara; Armstrong, Karla M.

    2006-12-19

    The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

  20. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

    SciTech Connect (OSTI)

    Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo

    2015-01-26

    Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

  1. ARM - Measurement - Aerosol extinction

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Aerosol extinction The removal of radiant energy from an incident beam by the process of aerosol absorption ...

  2. Piezoelectric-tuned microwave cavity for absorption spectrometry

    DOE Patents [OSTI]

    Leskovar, Branko; Buscher, Harold T.; Kolbe, William F.

    1978-01-01

    Gas samples are analyzed for pollutants in a microwave cavity that is provided with two highly polished walls. One wall of the cavity is mechanically driven with a piezoelectric transducer at a low frequency to tune the cavity over a band of microwave frequencies in synchronism with frequency modulated microwave energy applied to the cavity. Absorption of microwave energy over the tuned frequencies is detected, and energy absorption at a particular microwave frequency is an indication of a particular pollutant in the gas sample.

  3. Absorptive separation of NO from dilute off-gas

    SciTech Connect (OSTI)

    Zapfel, W.; Marr, R.; Siebenhofer, M.

    1999-04-01

    With regard to its negligible absorption properties, the separation of nitrogen monoxide from dilute off-gas is limited to bench-scale experiments. Investigation has been centered on improving the rate of absorption by the use of complex-forming additives based on iron(II) compounds. Further efforts have been made to improve the separation efficiency by the use of reactive additives. Due to the low reactivity of nitrogen monoxide, these attempts did not succeed. The oxidation of moderately concentrated off-gas with ozone and the absorption of the so-formed nitrogen dioxide have been reported. Technical as well as economical considerations do not permit the application of the process to the treatment of dilute off-gas. The principle underlying this process led to the investigation of direct oxidation of the off-gas under electrical discharge followed by absorption with aqueous diamide solution. Temperature and moisture of the off-gas have been considered, in addition to various feed contents of nitrogen monoxide. The results of this investigation show that direct oxidation of nitrogen monoxide by corona discharge is possible. The rate of conversion increases with increasing gas velocity, accompanied by a decreasing specific energy consumption. Applied to tunnel off-gas purification, the direct oxidation route seems to offer promising technical boundaries as it is accompanied by efficient particle separation.

  4. Methods for deacidizing gaseous mixtures by phase enhanced absorption

    DOE Patents [OSTI]

    Hu, Liang

    2012-11-27

    An improved process for deacidizing a gaseous mixture using phase enhanced gas-liquid absorption is described. The process utilizes a multiphasic absorbent that absorbs an acid gas at increased rate and leads to reduced overall energy costs for the deacidizing operation.

  5. RECTIFIED ABSORPTION METHOD FOR THE SEPARATION OF HYDROGEN ISOTOPES

    DOE Patents [OSTI]

    Hunt, C.D.; Hanson, D.N.

    1961-10-17

    A method is described for separating and recovering heavy hydrogen isotopes from gaseous mixtures by multiple stage cyclic absorption and rectification from an approximate solvent. In particular, it is useful for recovering such isoteoes from ammonia feedstock streams containing nitrogen solvent. Modifications of the process ranging from isobaric to isothermal are provided. Certain impurities are tolerated, giving advantages over conventional fractional distillation processes. (AEC)

  6. High temperature absorption heat pump for industrial usage

    SciTech Connect (OSTI)

    Bugarel, R.; Morillon, R.

    1982-01-01

    A theoretical and experimental study has demonstrated that an absorption heat pump with a water-lithium bromide thermodynamic couple has a practical coefficient of performance of 1.4-1.6 when providing a 280/sup 0/F heat source. The ability to serve as a high-temperature heat source makes this heat pump suitable for certain industrial processes such as drying.

  7. Separation of distinct photoexcitation species in femtosecond transient absorption microscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xiao, Kai; Ma, Ying -Zhong; Simpson, Mary Jane; Doughty, Benjamin; Yang, Bing

    2016-02-03

    Femtosecond transient absorption microscopy is a novel chemical imaging capability with simultaneous high spatial and temporal resolution. Although several powerful data analysis approaches have been developed and successfully applied to separate distinct chemical species in such images, the application of such analysis to distinguish different photoexcited species is rare. In this paper, we demonstrate a combined approach based on phasor and linear decomposition analysis on a microscopic level that allows us to separate the contributions of both the excitons and free charge carriers in the observed transient absorption response of a composite organometallic lead halide perovskite film. We found spatialmore » regions where the transient absorption response was predominately a result of excitons and others where it was predominately due to charge carriers, and regions consisting of signals from both contributors. Lastly, quantitative decomposition of the transient absorption response curves further enabled us to reveal the relative contribution of each photoexcitation to the measured response at spatially resolved locations in the film.« less

  8. Towards higher stability of resonant absorption measurements in pulsed plasmas

    SciTech Connect (OSTI)

    Britun, Nikolay; Michiels, Matthieu; Snyders, Rony

    2015-12-15

    Possible ways to increase the reliability of time-resolved particle density measurements in pulsed gaseous discharges using resonant absorption spectroscopy are proposed. A special synchronization, called “dynamic source triggering,” between a gated detector and two pulsed discharges, one representing the discharge of interest and another being used as a reference source, is developed. An internal digital delay generator in the intensified charge coupled device camera, used at the same time as a detector, is utilized for this purpose. According to the proposed scheme, the light pulses from the reference source follow the gates of detector, passing through the discharge of interest only when necessary. This allows for the utilization of short-pulse plasmas as reference sources, which is critical for time-resolved absorption analysis of strongly emitting pulsed discharges. In addition to dynamic source triggering, the reliability of absorption measurements can be further increased using simultaneous detection of spectra relevant for absorption method, which is also demonstrated in this work. The proposed methods are illustrated by the time-resolved measurements of the metal atom density in a high-power impulse magnetron sputtering (HiPIMS) discharge, using either a hollow cathode lamp or another HiPIMS discharge as a pulsed reference source.

  9. Monitoring PVD metal vapors using laser absorption spectroscopy

    SciTech Connect (OSTI)

    Braun, D.G.; Anklam, T.M.; Berzins, L.V.; Hagans, K.G.

    1994-04-01

    Laser absorption spectroscopy (LAS) has been used by the Atomic Vapor Laser Isotope Separation (AVLIS) program for over 10 years to monitor the co-vaporization of uranium and iron in its separators. During that time, LAS has proven to be an accurate and reliable method to monitor both the density and composition of the vapor. It has distinct advantages over other rate monitors, in that it is completely non-obtrusive to the vaporization process and its accuracy is unaffected by the duration of the run. Additionally, the LAS diagnostic has been incorporated into a very successful process control system. LAS requires only a line of sight through the vacuum chamber, as all hardware is external to the vessel. The laser is swept in frequency through an absorption line of interest. In the process a baseline is established, and the line integrated density is determined from the absorption profile. The measurement requires no hardware calibration. Through a proper choice of the atomic transition, a wide range of elements and densities have been monitored (e.g. nickel, iron, cerium and gadolinium). A great deal of information about the vapor plume can be obtained from the measured absorption profiles. By monitoring different species at the same location, the composition of the vapor is measured in real time. By measuring the same density at different locations, the spatial profile of the vapor plume is determined. The shape of the absorption profile is used to obtain the flow speed of the vapor. Finally, all of the above information is used evaluate the total vaporization rate.

  10. Temperature activated absorption during laser-induced damage: The evolution of laser-supported solid-state absorption fronts

    SciTech Connect (OSTI)

    Carr, C W; Bude, J D; Shen, N; Demange, P

    2010-10-26

    Previously we have shown that the size of laser induced damage sites in both KDP and SiO{sub 2} is largely governed by the duration of the laser pulse which creates them. Here we present a model based on experiment and simulation that accounts for this behavior. Specifically, we show that solid-state laser-supported absorption fronts are generated during a damage event and that these fronts propagate at constant velocities for laser intensities up to 4 GW/cm{sup 2}. It is the constant absorption front velocity that leads to the dependence of laser damage site size on pulse duration. We show that these absorption fronts are driven principally by the temperature-activated deep sub band-gap optical absorptivity, free electron transport, and thermal diffusion in defect-free silica for temperatures up to 15,000K and pressures < 15GPa. In addition to the practical application of selecting an optimal laser for pre-initiation of large aperture optics, this work serves as a platform for understanding general laser-matter interactions in dielectrics under a variety of conditions.

  11. Enhanced Solar Energy Absorption by Internally-mixed Black Carbon in Snow Grains

    SciTech Connect (OSTI)

    Flanner, M. G.; Liu, Xiaohong; Zhou, Cheng; Penner, Joyce E.; Jiao, C.

    2012-05-30

    Here we explore light absorption by snowpack containing black carbon (BC) particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0:05-109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA) (Chylek and Srivastava, 1983) is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8-2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only {approx}2% of the atmospheric BC burden is cloud-borne, 71-83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32-73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43-86%, relative to scenarios that apply external optical properties to all BC. We show that snow metamorphism

  12. ARM Aerosol Working Group Meeting

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    - all sites * Aerosol Sampling - SGP, NSA, AMF - scattering, absorption, number, size ... (Germany, 2007) * Near Future: - ISDAC (NSA, 2008) - AMF (China, 2008) AWG Research ...

  13. Lithium bromide absorption chiller passes gas conditioning field test

    SciTech Connect (OSTI)

    Lane, M.J.; Huey, M.A.

    1995-07-31

    A lithium bromide absorption chiller has been successfully used to provide refrigeration for field conditioning of natural gas. The intent of the study was to identify a process that could provide a moderate level of refrigeration necessary to meet the quality restrictions required by natural-gas transmission companies, minimize the initial investment risk, and reduce operating expenses. The technology in the test proved comparatively less expensive to operate than a propane refrigeration plant. Volatile product prices and changes in natural-gas transmission requirements have created the need for an alternative to conventional methods of natural-gas processing. The paper describes the problems with the accumulation of condensed liquids in pipelines, gas conditioning, the lithium bromide absorption cycle, economics, performance, and operating and maintenance costs.

  14. Corrosion of materials in absorption heating and refrigeration fluids

    SciTech Connect (OSTI)

    Griess, J.C.; DeVan, J.H.; Perez Blanco, H.

    1985-06-01

    The corrosion of metals and alloys in absorption refrigeration fluids has received little attention except for the behavior of steel and copper alloys in aqueous lithium bromide solutions. This report presents results of short-term corrosion tests on several materials in lithium bromide solutions as well as in other fluids of potential interest in advanced absorption machines. All materials tested had extremely high resistance to organic fluids, but in the aqueous systems some of the materials underwent localized attack. Type 304 stainless steel had acceptable corrosion resistance in most environments, but it underwent stress corrosion cracking in oxygen- or chromate-containing lithium bromide and even in the unstressed condition was subject to intergranular attack in hot concentrated caustic solutions. 10 refs., 2 figs., 4 tabs.

  15. Quantum fluctuations and saturable absorption in mesoscale lasers

    SciTech Connect (OSTI)

    Roy-Choudhury, Kaushik [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484 (United States); Levi, A. F. J. [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484 (United States); Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089-2533 (United States)

    2011-04-15

    We present a quantum-mechanical treatment of fluctuations and saturable absorption in mesoscale lasers. The time evolution of the density matrix is obtained from numerical integration and field-field and intensity-intensity correlations are calculated to obtain steady-state linewidth and photon statistics. Inclusion of a saturable absorber in the otherwise homogeneous medium is shown to suppress lasing, increase fluctuations, and enhance spontaneous emission near threshold.

  16. Broken-cloud enhancement of solar radiation absorption

    SciTech Connect (OSTI)

    Byrne, R.N.; Somerville, R.C.; Subasilar, B.

    1996-04-01

    Two papers recently published in Science have shown that there is more absorption of solar radiation than estimated by current atmospheric general circulation models (GCMs) and that the discrepancy is associated with cloudy scenes. We have devised a simple model which explains this as an artifact of stochastic radiative transport. We first give a heuristic description, unencumbered by mathematical detail. Consider a simple case with clouds distributed at random within a single level whose upper and lower boundaries are fixed. The solar zenith angle is small to moderate; this is therefore an energetically important case. Fix the average areal liquid water content of the cloud layer, and take the statistics of the cloud distribution to be homogeneous within the layer. Furthermore, assume that all the clouds in the layer have the same liquid water content, constant throughout the cloud, and that apart from their droplet content they are identical to the surrounding clear sky. Let the clouds occupy on the average a fraction p{sub cld} of the volume of the cloudy layer, and let them have a prescribed distribution of sizes about some mean. This is not a fractal distribution, because it has a scale. Cloud shape is unimportant so long as cloud aspect ratios are not far from unity. Take the single-scattering albedo to be unity for the droplets in the clouds. All of the absorption is due to atmospheric gases, so the absorption coefficient at a point is the same for cloud and clear sky. Absorption by droplets is less than 10% effect in the numerical stochastic radiation calculations described below, so it is reasonable to neglect it at this level of idealization.

  17. Diffraction: Enhanced Light Absorption of Solar Cells and Photodetectors -

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Energy Innovation Portal Solar Thermal Solar Thermal Solar Photovoltaic Solar Photovoltaic Advanced Materials Advanced Materials Find More Like This Return to Search Diffraction: Enhanced Light Absorption of Solar Cells and Photodetectors Sandia National Laboratories Contact SNL About This Technology Publications: PDF Document Publication Market Sheet (890 KB) Technology Marketing SummaryThe solar and photovoltaic industry has grown steadily over the last several years. In order to maintain

  18. Hydrogen Absorption Induced Metal Deposition on Palladium and

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Palladium-Alloy Particles - Energy Innovation Portal Hydrogen Absorption Induced Metal Deposition on Palladium and Palladium-Alloy Particles Brookhaven National Laboratory Contact BNL About This Technology <p> High resolution electron micrograph of a palladium nanoparticle coated with a monolayer of platinum</p> High resolution electron micrograph of a palladium nanoparticle coated with a monolayer of platinum Technology Marketing Summary Platinum is an excellent catalyst for

  19. Collision-induced vibrational absorption in molecular hydrogens

    SciTech Connect (OSTI)

    Reddy, S.P.

    1993-05-01

    Collision induced absorption (CIA) spectra of the first overtone bands of H{sub 2}, D{sub 2}, and HD have been recorded for gas densities up to 500 amagat at 77-300 K. Analyses of these spectra reveal that (1) contrary to the observations in the fundamental bands, the contribution of the isotropic overlap interaction to the first overtone bands is negligible, (2) the squares of the matrix elements B{sub 32}(R)/ea{sub o} [= {lambda}{sub 32} exp(-(R-{sigma})/{rho}{sub 32}) + 3 (R/a{sub o}){sup -4}] where the subscripts 3 and 2 represent L and {lambda}, respectively, account for the absorption intensity of the bands and (3) the mixed term, 2,3 {lambda}{sub 32} exp (-(R-{sigma})/{rho}{sub 32}) <{vert_bar}Q{vert_bar}> <{alpha}> (R/a){sup -4}, gives a negative contribution. In the CIA spectra of H{sub 2} in its second overtone region recorded at 77, 201 and 298 K for gas densities up to 1000 amagat, a dip in the Q branch with characteristic Q{sub p} and Q{sub R} components has been observed. The analysis of the absorption profiles reveals, in addition to the previously known effects, the occurrence of the triple-collision transitions of H{sub 2} of the type Q{sub 1}(J) + Q{sub 1}(J) + Q{sub 1}(J) for the first time. From the profile analysis the absorption coefficient of these transitions is obtained.

  20. Method for making a photodetector with enhanced light absorption

    DOE Patents [OSTI]

    Kane, James

    1987-05-05

    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  1. Waste heat driven absorption refrigeration process and system

    DOE Patents [OSTI]

    Wilkinson, William H.

    1982-01-01

    Absorption cycle refrigeration processes and systems are provided which are driven by the sensible waste heat available from industrial processes and other sources. Systems are disclosed which provide a chilled water output which can be used for comfort conditioning or the like which utilize heat from sensible waste heat sources at temperatures of less than 170.degree. F. Countercurrent flow equipment is also provided to increase the efficiency of the systems and increase the utilization of available heat.

  2. Method for processing seismic data to identify anomalous absorption zones

    DOE Patents [OSTI]

    Taner, M. Turhan

    2006-01-03

    A method is disclosed for identifying zones anomalously absorptive of seismic energy. The method includes jointly time-frequency decomposing seismic traces, low frequency bandpass filtering the decomposed traces to determine a general trend of mean frequency and bandwidth of the seismic traces, and high frequency bandpass filtering the decomposed traces to determine local variations in the mean frequency and bandwidth of the seismic traces. Anomalous zones are determined where there is difference between the general trend and the local variations.

  3. A cryogenic circulating advective multi-pass absorption cell

    SciTech Connect (OSTI)

    Stockett, M. H.; Lawler, J. E. [Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2012-03-15

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 10{sup 7} cm{sup -3}. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.

  4. Aqueous absorption fluids. Annual report, July 1989-October 1990

    SciTech Connect (OSTI)

    Langeliers, J.; Chandler, T.; Rockenfeller, U.

    1990-11-01

    The report describes the third year of study of aqueous-based working fluids that will allow air-cooled absorption chiller operation. The successful development of such fluids will eliminate the need for cooling towers in gas-fired chiller equipment for residential and unitary markets and possibly allow for building heating with absorber heat. The thermophysical property measurements were completed and the vapor pressure and specific heat data were used to compute the enthalpy of LB621-H2O solutions. Solution film heat transfer coefficients were measured in the test sorber apparatus and a dramatic increase in film heat transfer was observed in the presence of heat transfer additives. Measured equilibrium and film heat transfer data were used in the single-stage absorption cycle computer model to analyze the potential performance of LB621-H2O; the analysis confirmed the superiority of LB621-H2O as a single-stage working fluid. In addition, thermal stability and corrosion rate tests demonstrated that LB621-H2O is stable and non-corrosive in a single-stage absorption chiller environment.

  5. PROMINENCE PLASMA DIAGNOSTICS THROUGH EXTREME-ULTRAVIOLET ABSORPTION

    SciTech Connect (OSTI)

    Landi, E.; Reale, F.

    2013-07-20

    In this paper, we introduce a new diagnostic technique that uses EUV and UV absorption to determine the electron temperature and column emission measure, as well as the He/H relative abundance of the absorbing plasma. If a realistic assumption on the geometry of the latter can be made and a spectral code such as CHIANTI is used, then this technique can also yield the absorbing plasma hydrogen and electron density. This technique capitalizes on the absorption properties of hydrogen and helium at different wavelength ranges and temperature regimes. Several cases where this technique can be successfully applied are described. This technique works best when the absorbing plasma is hotter than 15,000 K. We demonstrate this technique on AIA observations of plasma absorption during a coronal mass ejection eruption. This technique can be easily applied to existing observations of prominences and cold plasmas in the Sun from almost all space missions devoted to the study of the solar atmosphere, which we list.

  6. Regional respiratory tract absorption of inhaled reactive gases

    SciTech Connect (OSTI)

    Miller, F.J.; Overton, J.H.; Kimbell, J.S.; Russell, M.L.

    1992-06-29

    Highly reactive gases present unique problems due to the number of factors which must be taken into account to determine regional respiratory tract uptake. The authors reviewed some of the physical, chemical, and biological factors that affect dose and that must be understood to interpret toxicological data, to evaluate experimental dosimetry studies, and to develop dosimetry models. Selected dosimetry experiments involving laboratory animals and humans were discussed, showing the variability and uptake according to animal species and respiratory tract region for various reactive gases. New experimental dosimetry approaches, such as those involving isotope ratio mass spectroscopy and cyclotron generation reactive gases, were discussed that offer great promise for improving the ability to study regional respiratory tract absorption of reactive gases. Various dosimetry modeling applications were discussed which demonstrate: the importance of airflow patterns for site-specific dosimetry in the upper respiratory tract, the influence of the anatomical model used to make inter- and intraspecies dosimetric comparisons, the influence of tracheobronchial path length on predicted dose curves, and the implications of ventilatory unit structure and volume on dosimetry and response. Collectively, these examples illustrate important aspects of regional respiratory tract absorption of inhaled reactive gases. Given the complex nature of extent and pattern of injury in the respiratory tract from exposure to reactive gases, understanding interspecies differences in the absorption of reactive gases will continue to be an important area for study.

  7. Waste Heat Powered Ammonia Absorption Refrigeration Unit for LPG Recovery

    SciTech Connect (OSTI)

    Donald C, Energy Concepts Co.; Lauber, Eric, Western Refining Co.

    2008-06-20

    An emerging DOE-sponsored technology has been deployed. The technology recovers light ends from a catalytic reformer plant using waste heat powered ammonia absorption refrigeration. It is deployed at the 17,000 bpd Bloomfield, New Mexico refinery of Western Refining Company. The technology recovers approximately 50,000 barrels per year of liquefied petroleum gas that was formerly being flared. The elimination of the flare also reduces CO2 emissions by 17,000 tons per year, plus tons per year reductions in NOx, CO, and VOCs. The waste heat is supplied directly to the absorption unit from the Unifiner effluent. The added cooling of that stream relieves a bottleneck formerly present due to restricted availability of cooling water. The 350oF Unifiner effluent is cooled to 260oF. The catalytic reformer vent gas is directly chilled to minus 25oF, and the FCC column overhead reflux is chilled by 25oF glycol. Notwithstanding a substantial cost overrun and schedule slippage, this project can now be considered a success: it is both profitable and highly beneficial to the environment. The capabilities of directly-integrated waste-heat powered ammonia absorption refrigeration and their benefits to the refining industry have been demonstrated.

  8. Heat exchanger bypass system for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C.

    1984-01-01

    A heat exchanger bypass system for an absorption refrigeration system is disclosed. The bypass system operates to pass strong solution from the generator around the heat exchanger to the absorber of the absorption refrigeration system when strong solution builds up in the generator above a selected level indicative of solidification of strong solution in the heat exchanger or other such blockage. The bypass system includes a bypass line with a gooseneck located in the generator for controlling flow of strong solution into the bypass line and for preventing refrigerant vapor in the generator from entering the bypass line during normal operation of the refrigeration system. Also, the bypass line includes a trap section filled with liquid for providing a barrier to maintain the normal pressure difference between the generator and the absorber even when the gooseneck of the bypass line is exposed to refrigerant vapor in the generator. Strong solution, which may accumulate in the trap section of the bypass line, is diluted, to prevent solidification, by supplying weak solution to the trap section from a purge system for the absorption refrigeration system.

  9. X-ray absorption fine-structure spectroscopy (Book) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    X-ray absorption fine-structure spectroscopy Citation Details In-Document Search Title: X-ray absorption fine-structure spectroscopy Authors: Newville, M. 1 + Show Author ...

  10. Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP Applications, April 2005 Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP...

  11. New packing in absorption systems for trapping benzene from coke-oven gas

    SciTech Connect (OSTI)

    V.V. Grabko; V.M. Li; T.A. Shevchenko; M.A. Solov'ev

    2009-07-15

    The efficiency of benzene removal from coke-oven gas in absorption units OAO Alchevskkoks with new packing is assessed.

  12. Advantages and disadvantages of using absorption chillers to lower utility bills

    SciTech Connect (OSTI)

    Kistler, P.

    1997-04-01

    Absorption chillers have a proven history of providing low-cost reliable cooling and should continue to do so in the future. Absorption chiller systems can provide significant energy savings for a particular application. To maximize savings, the various system arrangements should be evaluated; for example, single effect versus double effect, chiller versus chiller/heater, straight absorption chiller or the electric/absorption hybrid.

  13. Absorption Features in Spectra of Magnetized Neutron Stars

    SciTech Connect (OSTI)

    Suleimanov, V.; Hambaryan, V.; Neuhaeuser, R.; Potekhin, A. Y.; Pavlov, G. G.; Adelsberg, M. van; Werner, K.

    2011-09-21

    The X-ray spectra of some magnetized isolated neutron stars (NSs) show absorption features with equivalent widths (EWs) of 50-200 eV, whose nature is not yet well known.To explain the prominent absorption features in the soft X-ray spectra of the highly magnetized (B{approx}10{sup 14} G) X-ray dim isolated NSs (XDINSs), we theoretically investigate different NS local surface models, including naked condensed iron surfaces and partially ionized hydrogen model atmospheres, with semi-infinite and thin atmospheres above the condensed surface. We also developed a code for computing light curves and integral emergent spectra of magnetized neutron stars with various temperature and magnetic field distributions over the NS surface. We compare the general properties of the computed and observed light curves and integral spectra for XDINS RBS 1223 and conclude that the observations can be explained by a thin hydrogen atmosphere above the condensed iron surface, while the presence of a strong toroidal magnetic field component on the XDINS surface is unlikely.We suggest that the harmonically spaced absorption features in the soft X-ray spectrum of the central compact object (CCO) 1E 1207.4-5209 (hereafter 1E 1207) correspond to peaks in the energy dependence of the free-free opacity in a quantizing magnetic field, known as quantum oscillations. To explore observable properties of these quantum oscillations, we calculate models of hydrogen NS atmospheres with B{approx}10{sup 10}-10{sup 11} G(i.e., electron cyclotron energy E{sub c,e}{approx}0.1-1 keV) and T{sub eff} = 1-3 MK. Such conditions are thought to be typical for 1E 1207. We show that observable features at the electron cyclotron harmonics with EWs {approx_equal}100-200 eV can arise due to these quantum oscillations.

  14. Absorption-emission optrode and methods of use thereof

    DOE Patents [OSTI]

    Hirschfeld, T.B.

    1990-05-29

    A method and apparatus are described for monitoring the physical and chemical properties of a sample fluid by measuring an optical signal generated by a fluorescent substance and modulated by an absorber substance. The emission band of the fluorescent substance overlaps the absorption band of the absorber substance, and the degree of overlap is dependent on the physical and chemical properties of the sample fluid. The fluorescent substance and absorber substance are immobilized on a substrate so that an effective number of molecules thereof are sufficiently close for resonant energy transfer to occur, thereby providing highly efficient modulation of the fluorescent emissions of the fluorescent substance by the absorber substance. 4 figs.

  15. Absorption-emission optrode and methods of use thereof

    DOE Patents [OSTI]

    Hirschfeld, Tomas B.

    1990-01-01

    A method and apparatus for monitoring the physical and chemical properties of a sample fluid by measuring an optical signal generated by a fluorescent substance and modulated by an absorber substance. The emission band of the fluorescent substance overlaps the absorption band of the absorber substance, and the degree of overlap is dependent on the physical and chemical properties of the sample fluid. The fluorescent substance and absorber substance are immobilized on a substrate so that an effective number of molecules thereof are sufficiently close for resonant energy transfer to occur, thereby providing highly efficient modulation of the fluorescent emissions of the fluorescent substance by the absorber substance.

  16. High Energy Absorption Top Nozzle For A Nuclaer Fuel Assembly

    DOE Patents [OSTI]

    Sparrow, James A.; Aleshin, Yuriy; Slyeptsov, Aleksey

    2004-05-18

    A high energy absorption top nozzle for a nuclear fuel assembly that employs an elongated upper tubular housing and an elongated lower tubular housing slidable within the upper tubular housing. The upper and lower housings are biased away from each other by a plurality of longitudinally extending springs that are restrained by a longitudinally moveable piston whose upward travel is limited within the upper housing. The energy imparted to the nozzle by a control rod scram is mostly absorbed by the springs and the hydraulic affect of the piston within the nozzle.

  17. Absorption spectroscopy of a laboratory photoionized plasma experiment at Z

    SciTech Connect (OSTI)

    Hall, I. M.; Durmaz, T.; Mancini, R. C.; Bailey, J. E.; Rochau, G. A.; Golovkin, I. E.; MacFarlane, J. J.

    2014-03-15

    The Z facility at the Sandia National Laboratories is the most energetic terrestrial source of X-rays and provides an opportunity to produce photoionized plasmas in a relatively well characterised radiation environment. We use detailed atomic-kinetic and spectral simulations to analyze the absorption spectra of a photoionized neon plasma driven by the x-ray flux from a z-pinch. The broadband x-ray flux both photoionizes and backlights the plasma. In particular, we focus on extracting the charge state distribution of the plasma and the characteristics of the radiation field driving the plasma in order to estimate the ionisation parameter.

  18. Infrared absorption spectroscopy and chemical kinetics of free radicals

    SciTech Connect (OSTI)

    Curl, R.F.; Glass, G.P.

    1993-12-01

    This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

  19. Energy Saving Absorption Heat Pump Water Heater - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Security Administration | (NNSA) Energy Saving "Cool Roofs" Installed at Y-12 October 17, 2012 The Y-12 National Security Complex has taken additional steps to reduce its energy costs by installing almost 100,000 square feet of new heat reflective "cool" roofs at the Oak Ridge, Tennessee facility. File 2012-10-17 NPO Y-12 Cool Roofs.docx

    Building Energy Efficiency Building Energy Efficiency Find More Like This Return to Search Energy Saving Absorption Heat Pump Water

  20. IHT: Tools for Computing Insolation Absorption by Particle Laden Flows

    SciTech Connect (OSTI)

    Grout, R. W.

    2013-10-01

    This report describes IHT, a toolkit for computing radiative heat exchange between particles. Well suited for insolation absorption computations, it is also has potential applications in combustion (sooting flames), biomass gasification processes and similar processes. The algorithm is based on the 'Photon Monte Carlo' approach and implemented in a library that can be interfaced with a variety of computational fluid dynamics codes to analyze radiative heat transfer in particle-laden flows. The emphasis in this report is on the data structures and organization of IHT for developers seeking to use the IHT toolkit to add Photon Monte Carlo capabilities to their own codes.

  1. Use Low-Grade Waste Steam to Power Absorption Chillers | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Low-Grade Waste Steam to Power Absorption Chillers Use Low-Grade Waste Steam to Power Absorption Chillers This tip sheet on waste steam to power absorption chillers provides how-to advice for improving steam systems using low-cost, proven practices and technologies. STEAM TIP SHEET #14 Use Low-Grade Waste Steam to Power Absorption Chillers (January 2012) (431.31 KB) More Documents & Publications Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP Applications,

  2. Low level absorptance measurements and scans of high performance optical coatings for atomic vapor laser isotope separation applications

    SciTech Connect (OSTI)

    Chow, R.; Taylor, J.R.; Wu, Z.L.; Krupka, R.; Yang, T.

    1998-01-24

    A surface thermal lensing and a radiometric technique was used to characterize the absorptance dependence on time, power, site, and technique of low absorptance optical multilayered coatings.

  3. Hydrogen Absorption in Pd-based Nanostructures - Final Report

    SciTech Connect (OSTI)

    David Lederman

    2012-10-22

    Pd is known to absorb hydrogen. Molecules are normally chemisorbed at the surface in a process where the molecule breaks into two hydrogen atoms, and the protons are then absorbed into the bulk. This process consists of electron filling holes in the Pd 4d band near the Fermi energy, which due to the high density of states at the Fermi energy, is an energetically favorable process. Our aim with this project was to determine possible changes in magnetic properties with Pd nm-length-scale thick layers intercalated by magnetic materials. Before the start of this work, the literature indicated that there were several possible scenarios by which this could happen: i) the Pd will be magnetized due to a proximity effect with nearby magnetic layers, resulting in changes in the magnetization due to H2 absorption; ii) some H will be absorbed into the magnetic layers, causing a change in the magnetic exchange interactions; or iii) absorption of H2 will cause an expansion of the lattice, resulting in a magnetoelastic effect which changes the magnetic properties.

  4. Absorption process for producing oxygen and nitrogen and solution therefor

    DOE Patents [OSTI]

    Roman, I.C.; Baker, R.W.

    1990-09-25

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible. 1 figure

  5. Absorption of the omega and phi mesons in nuclei

    SciTech Connect (OSTI)

    Chaden Djalali, Michael H. Wood, Michael Paolone, Rakhsha Nasseripour, Dennis P. Weygand

    2012-04-01

    The properties of hadrons, such as their masses and widths, are predicted to be modified in dense and/or hot nuclear matter. Particular attention has been given to the modifications of vector-meson properties in ordinary nuclear matter where chiral symmetry is predicted to be partially restored due to a change in the quark condensate. Different models predict relatively large measurable changes in the mass and/or the width of these mesons. The e{sup +}e{sup -} decay channel of these mesons has negligible final-state interactions (FSI), providing an ideal tool to study their possible in-medium modifications Due to its short lifetime, the {rho} meson has a substantial probability of decaying in the nucleus and its study has been previously reported. Due to their long lifetimes, the {omega} and {phi} mesons are ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. These mesons have been photo-produced in several targets ranging from deuterium to lead. Nuclear transparencies ratios have been derived for different decay channels. These ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the {omega} meson is stronger than that reported by the CBELSATAPS experiment. These results are compared to recent theoretical models.

  6. Effects of thermal motion on electromagnetically induced absorption

    SciTech Connect (OSTI)

    Tilchin, E.; Wilson-Gordon, A. D.; Firstenberg, O.

    2011-05-15

    We describe the effect of thermal motion and buffer-gas collisions on a four-level closed N system interacting with strong pump(s) and a weak probe. This is the simplest system that experiences electromagnetically induced absorption (EIA) due to transfer of coherence via spontaneous emission from the excited state to the ground state. We investigate the influence of Doppler broadening, velocity-changing collisions (VCC), and phase-changing collisions (PCC) with a buffer gas on the EIA spectrum of optically active atoms. In addition to exact expressions, we present an approximate solution for the probe absorption spectrum, which provides physical insight into the behavior of the EIA peak due to VCC, PCC, and the wave-vector difference between the pump and probe beams. VCC are shown to produce a wide pedestal at the base of the EIA peak, which is scarcely affected by the pump-probe angular deviation, whereas the sharp central EIA peak becomes weaker and broader due to the residual Doppler-Dicke effect. Using diffusionlike equations for the atomic coherences and populations, we construct a spatial-frequency filter for a spatially structured probe beam and show that Ramsey narrowing of the EIA peak is obtained for beams of finite width.

  7. Triple loop heat exchanger for an absorption refrigeration system

    DOE Patents [OSTI]

    Reimann, Robert C.

    1984-01-01

    A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

  8. THE ABSORPTION OF HYDROGEN ON LOW PRESSURE HYDRIDE MATERIALS

    SciTech Connect (OSTI)

    Morgan, G.; Korinko, P.

    2012-04-03

    For this study, hydrogen getter materials (Zircaloy-4 and pure zirconium) that have a high affinity for hydrogen (and low overpressure) have been investigated to determine the hydrogen equilibrium pressure on Zircaloy-4 and pure zirconium. These materials, as with most getter materials, offered significant challenges to overcome given the low hydrogen equilibrium pressure for the temperature range of interest. Hydrogen-zirconium data exists for pure zirconium at 500 C and the corresponding hydrogen overpressure is roughly 0.01 torr. This manuscript presents the results of the equilibrium pressures for the absorption and desorption of hydrogen on zirconium materials at temperatures ranging from 400 C to 600 C. The equilibrium pressures in this temperature region range from 150 mtorr at 600 C to less than 0.1 mtorr at 400 C. It has been shown that the Zircaloy-4 and zirconium samples are extremely prone to surface oxidation prior to and during heating. This oxidation precludes the hydrogen uptake, and therefore samples must be heated under a minimum vacuum of 5 x 10{sup -6} torr. In addition, the Zircaloy-4 samples should be heated at a sufficiently low rate to maintain the system pressure below 0.5 mtorr since an increase in pressure above 0.5 mtorr could possibly hinder the H{sub 2} absorption kinetics due to surface contamination. The results of this study and the details of the testing protocol will be discussed.

  9. Absorption process for producing oxygen and nitrogen and solution therefor

    DOE Patents [OSTI]

    Roman, Ian C. [Wilmington, DE; Baker, Richard W. [Palo Alto, CA

    1990-09-25

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

  10. Absorption process for producing oxygen and nitrogen and solution therefor

    DOE Patents [OSTI]

    Roman, Ian C.

    1984-01-01

    Process for the separation and purification of oxygen and nitrogen is disclosed which utilizes solutions of oxygen carriers to selectively absorb oxygen from a gaseous stream, leaving nitrogen as a byproduct. In the process, an oxygen carrier capable of reversibly binding molecular oxygen is dissolved in a solvent solution, which absorbs oxygen from an oxygen-containing gaseous feed stream such as atmospheric air and desorbs oxygen to a gaseous product stream. The feed stream is maintained at a sufficiently high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, while the product stream is maintained at a sufficiently low oxygen pressure to keep the carrier in its deoxygenated form during desorption. In an alternate mode of operation, the carrier solution is maintained at a sufficiently low temperature and high oxygen pressure to keep the oxygen carrier in its oxygenated form during absorption, and at a sufficiently high temperature to keep the carrier in its deoxygenated form during desorption. Under such conditions, exceptionally high oxygen concentrations on the order of 95% to 99% are obtained, as well as a long carrier lifetime in excess of 3 months, making the process commercially feasible.

  11. Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat

    SciTech Connect (OSTI)

    2010-09-01

    BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

  12. J/{psi} absorption in a multicomponent hadron gas

    SciTech Connect (OSTI)

    Prorok, D.; Turko, L.; Blaschke, D.

    2008-08-29

    A model for anomalous J/{psi} suppression in high energy heavy ion collisions is presented. As the additional suppression mechanism beyond standard nuclear absorption inelastic J/{psi} scattering with hadronic matter is considered. Hadronic matter is modeled as an evolving multi-component gas of point-like non-interacting particles (MCHG). Estimates for the sound velocity of the MCHG are given and the equation of state is compared with Lattice QCD data in the vicinity of the deconfinement phase transition. The approximate cooling pattern caused by longitudinal expansion is presented. It is shown that under these conditions the resulting J/{psi} suppression pattern agrees well with NA38 and NA50 data.

  13. Broadband enhancement of infrared absorption in microbolometers using Ag nanocrystals

    SciTech Connect (OSTI)

    Hyun, Jerome K.; Ahn, Chi Won; Kim, Woo Choong; Kim, Tae Hyun; Hyun, Moon Seop; Kim, Hee Yeoun E-mail: jhpark@nnfc.re.kr; Park, Jae Hong E-mail: jhpark@nnfc.re.kr; Lee, Won-Oh

    2015-12-21

    High performance microbolometers are widely sought for thermal imaging applications. In order to increase the performance limits of microbolometers, the responsivity of the device to broadband infrared (IR) radiation needs to be improved. In this work, we report a simple, quick, and cost-effective approach to modestly enhance the broadband IR response of the device by evaporating Ag nanocrystals onto the light entrance surface of the device. When irradiated with IR light, strong fields are built up within the gaps between adjacent Ag nanocrystals. These fields resistively generate heat in the nanocrystals and underlying substrate, which is transduced into an electrical signal via a resistive sensing element in the device. Through this method, we are able to enhance the IR absorption over a broadband spectrum and improve the responsivity of the device by ∼11%.

  14. Light absorption cell combining variable path and length pump

    DOE Patents [OSTI]

    Prather, William S.

    1993-01-01

    A device for use in making spectrophotometric measurements of fluid samples. In particular, the device is a measurement cell containing a movable and a fixed lens with a sample of the fluid therebetween and through which light shines. The cell is connected to a source of light and a spectrophotometer via optic fibers. Movement of the lens varies the path length and also pumps the fluid into and out of the cell. Unidirectional inlet and exit valves cooperate with the movable lens to assure a one-way flow of fluid through the cell. A linear stepper motor controls the movement of the lens and cycles it from a first position closer to the fixed lens and a second position farther from the fixed lens, preferably at least 10 times per minute for a nearly continuous stream of absorption spectrum data.

  15. Pulsed laser linescanner for a backscatter absorption gas imaging system

    DOE Patents [OSTI]

    Kulp, Thomas J.; Reichardt, Thomas A.; Schmitt, Randal L.; Bambha, Ray P.

    2004-02-10

    An active (laser-illuminated) imaging system is described that is suitable for use in backscatter absorption gas imaging (BAGI). A BAGI imager operates by imaging a scene as it is illuminated with radiation that is absorbed by the gas to be detected. Gases become "visible" in the image when they attenuate the illumination creating a shadow in the image. This disclosure describes a BAGI imager that operates in a linescanned manner using a high repetition rate pulsed laser as its illumination source. The format of this system allows differential imaging, in which the scene is illuminated with light at least 2 wavelengths--one or more absorbed by the gas and one or more not absorbed. The system is designed to accomplish imaging in a manner that is insensitive to motion of the camera, so that it can be held in the hand of an operator or operated from a moving vehicle.

  16. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    SciTech Connect (OSTI)

    Gary T. Rochelle; Eric Chen; J.Tim Cullinane; Marcus Hilliard; Jennifer Lu; Babatunde Oyenekan; Ross Dugas

    2004-07-29

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. CO{sub 2} mass transfer rates are second order in piperazine concentration and increase with ionic strength. Modeling of stripper performance suggests that 5 m K{sup +}/2.5 m PZ will require 25 to 46% less heat than 7 m MEA. The first pilot plant campaign was completed on June 24. The CO{sub 2} penetration through the absorber with 20 feet of Flexipac{trademark} 1Y varied from 0.6 to 16% as the inlet CO{sub 2} varied from 3 to 12% CO{sub 2} and the gas rate varied from 0.5 to 3 kg/m{sup 2}-s.

  17. Optimum hot water temperature for absorption solar cooling

    SciTech Connect (OSTI)

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R.; Zacarias, A.

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  18. Commercial absorption chiller models for evaluation of control strategies

    SciTech Connect (OSTI)

    Koeppel, E.A.; Klein, S.A.; Mitchell, J.W.

    1995-08-01

    A steady-state computer simulation model of a direct fired double-effect water-lithium bromide absorption chiller in the parallel-flow configuration was developed from first principles. Unknown model parameters such as heat transfer coefficients were determined by matching the model`s calculated state points and coefficient of performance (COP) against nominal full-load operating data and COPs obtained from a manufacturer`s catalog. The model compares favorably with the manufacturer`s performance ratings for varying water circuit (chilled and cooling) temperatures at full load conditions and for chiller part-load performance. The model was used (1) to investigate the effect of varying the water circuit flow rates with the chiller load and (2) to optimize chiller part-load performance with respect to the distribution and flow of the weak solution.

  19. Light absorption cell combining variable path and length pump

    DOE Patents [OSTI]

    Prather, W.S.

    1993-12-07

    A device is described for use in making spectrophotometric measurements of fluid samples. In particular, the device is a measurement cell containing a movable and a fixed lens with a sample of the fluid there between and through which light shines. The cell is connected to a source of light and a spectrophotometer via optic fibers. Movement of the lens varies the path length and also pumps the fluid into and out of the cell. Unidirectional inlet and exit valves cooperate with the movable lens to assure a one-way flow of fluid through the cell. A linear stepper motor controls the movement of the lens and cycles it from a first position closer to the fixed lens and a second position farther from the fixed lens, preferably at least 10 times per minute for a nearly continuous stream of absorption spectrum data. 2 figures.

  20. Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

    SciTech Connect (OSTI)

    Guddala, Sriram Kumar, Raghwendra; Ramakrishna, S. Anantha

    2015-03-16

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm{sup 2}.

  1. Femtosecond Chirp-Free Transient Absorption Method And Apparatus

    DOE Patents [OSTI]

    McBranch, Duncan W.; Klimov, Victor I.

    2001-02-20

    A method and apparatus for femtosecond transient absorption comprising phase-sensitive detection, spectral scanning and simultaneous controlling of a translation stage to obtain TA spectra information having at least a sensitivity two orders of magnitude higher than that for single-shot methods, with direct, simultaneous compensation for chirp as the data is acquired. The present invention includes a amplified delay translation stage which generates a splittable frequency-doubled laser signal at a predetermined frequency f, a controllable means for synchronously modulating one of the laser signals at a repetition rate of f/2, applying the laser signals to a material to be sample, and acquiring data from the excited sample while simultaneously controlling the controllable means for synchronously modulating.

  2. Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals

    SciTech Connect (OSTI)

    Curl, Robert F; Glass, Graham

    2004-11-01

    This research was directed at the detection, monitoring, and study of the chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. Work on the reaction of OH with acetaldehyde has been completed and published and work on the reaction of O({sup 1}D) with CH{sub 4} has been completed and submitted for publication. In the course of our investigation of branching ratios of the reactions of O({sup 1}D) with acetaldehyde and methane, we discovered that hot atom chemistry effects are not negligible at the gas pressures (13 Torr) initially used. Branching ratios of the reaction of O({sup 1}D) with CH{sub 4} have been measured at a tenfold higher He flow and fivefold higher pressure.

  3. Thermodynamic Evaluation of Hydrogen Absorption by Niobium During SRF Fabrication

    SciTech Connect (OSTI)

    Ricker, R. E.; Myneni, G. R.

    2011-03-31

    The properties and performance of the ultra high purity Nb used to fabricate superconducting radio frequency (SRF) particle accelerator cavities have been found to vary with processing conditions. One hypothesis for these variations is that hydrogen, absorbed during processing, is responsible for this behavior. The key assumption behind this hypothesis is that niobium can absorb hydrogen from one or more of the processing environments. This paper reviews work examining the validity of this assumption. It was determined that Nb will spontaneously react with water producing adsorbed atomic hydrogen that is readily absorbed into the metal. The passivating oxide film normally prevents this reaction, but this film is frequently removed during processing and it is attacked by the fluoride ion used in the polishing solutions for SRF cavities. However, during electropolishing that cathodic reduction of hydrogen is transferred to the auxiliary electrode and this should suppress hydrogen absorption.

  4. Multi-spectral optical absorption in substrate-free nanowire arrays

    SciTech Connect (OSTI)

    Zhang, Junpeng; Chia, Andrew; Boulanger, Jonathan; LaPierre, Ray; Dhindsa, Navneet; Khodadad, Iman; Saini, Simarjeet

    2014-09-22

    A method is presented of fabricating gallium arsenide (GaAs) nanowire arrays of controlled diameter and period by reactive ion etching of a GaAs substrate containing an indium gallium arsenide (InGaP) etch stop layer, allowing the precise nanowire length to be controlled. The substrate is subsequently removed by selective etching, using the same InGaP etch stop layer, to create a substrate-free GaAs nanowire array. The optical absorptance of the nanowire array was then directly measured without absorption from a substrate. We directly observe absorptance spectra that can be tuned by the nanowire diameter, as explained with rigorous coupled wave analysis. These results illustrate strong optical absorption suitable for nanowire-based solar cells and multi-spectral absorption for wavelength discriminating photodetectors. The solar-weighted absorptance above the bandgap of GaAs was 94% for a nanowire surface coverage of only 15%.

  5. Performance and analysis of absorption experiments on x-ray heated low-Z constrained samples

    SciTech Connect (OSTI)

    Lee, R.W.; Cauble, R.; Perry, T.S.; Springer, P.T.; Fields, D.F.; Bach, D.R.; Serduke, F.J.D.; Iglesias, C.A.; Rogers, F.J.; Nash, J.K.; Chen, M.H.; Wilson, B.G.; Goldstein, W.H.; Ward, R.A.; Kilkenny, J.D.; Doyas, R.; Da Silva, L.B.; Back, C.A.; Davidson, S.J.; Foster, J.M.; Smith, C.C.

    1996-05-01

    Results of experiments on the absorption of niobium in a hot, dense plasma are presented. These results represent a major step in the development of absorption techniques necessary for the quantitative characterization of hot, dense matter. A general discussion is presented of the requirements for performing quantitative analysis of absorption spectra. Hydrodynamic simulations are used to illustrate the behavior of tamped X-ray-heated matter and to indicate effects that can arise from the two dimensional aspects of the experiment. The absorption spectrum of a low-Z material, in this case aluminum, provides a temperature diagnostic and indicates the advance of the absorption measurement technique to the level of application. The experimental technique is placed in context with a review of other measurements using absorption spectroscopy to probe hot, dense matter.

  6. The Future of Absorption Technology in America: A Critical Look at the

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Impact of Building, Cooling, Heating, and Power (BCHP) and Innovation, June 2000 | Department of Energy The Future of Absorption Technology in America: A Critical Look at the Impact of Building, Cooling, Heating, and Power (BCHP) and Innovation, June 2000 The Future of Absorption Technology in America: A Critical Look at the Impact of Building, Cooling, Heating, and Power (BCHP) and Innovation, June 2000 Edmond Carré developed the first absorption machine in 1850, using water and sulfuric

  7. The Effect of Gas Absorption on the Scattered Radiation in the...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Gas Absorption on the Scattered Radiation in the Solar Almucantar: Results of Numerical ... albedo) from diffuse and direct radiation measured in the solar almucantar has ...

  8. A Technical and Economic Analysis of an Innovative Two-Step Absorption...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings A Technical and Economic Analysis ...

  9. X-Ray Absorption Spectroscopic Study of Sodium Iodide and Iodine...

    Office of Scientific and Technical Information (OSTI)

    Supercapacitor Citation Details In-Document Search Title: X-Ray Absorption Spectroscopic Study of Sodium Iodide and Iodine Mediators in a Solid-State Supercapacitor ...

  10. Effect of nonlinear absorption on electric field applied lead chloride by Z-scan technique

    SciTech Connect (OSTI)

    Rejeena, I.; Lillibai,; Nampoori, V. P. N.; Radhakrishnan, P.; Rahimkutty, M. H.

    2014-10-15

    The preparation, spectral response and optical nonlinearity of gel grown lead chloride single crystals subjected to electric field of 20V using parallel plate arrangements have been investigated. Optical band gap of the samples were determined using linear absorption spectra. Open aperture z-scan was employed for the determination of nonlinear absorption coefficient of PbCl{sub 2} solution. The normalized transmittance curve exhibits a valley shows reverse saturable absorption. The non linear absorption at different input fluences were recorded using a single Gaussian laser beam in tight focus geometry. The RSA nature of the sample makes it suitable for optical limiting applications.

  11. Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Look at the Impact of Building, Cooling, Heating, and Power (BCHP) and Innovation, June ... 2004 Photo credit: Oak Ridge National Lab Residential Absorption Heat Pump Water Heater

  12. VARIABLE SODIUM ABSORPTION IN A LOW-EXTINCTION TYPE Ia SUPERNOVA...

    Office of Scientific and Technical Information (OSTI)

    We present the third detection of such variable absorption, based on six epochs of ... Country of Publication: United States Language: English Subject: 74 ATOMIC AND MOLECULAR ...

  13. Use Low-Grade Waste Steam to Power Absorption Chillers | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    (LiBr) Absorption for CHP Applications, April 2005 Improving Steam System Performance: A Sourcebook for Industry, Second Edition Flash High-Pressure Condensate to Regenerate Low

  14. Correction. Sunlight absorption in water – efficiency and design implications for photoelectrochemical devices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Döscher, H.; Geisz, J. F.; Deutsch, T. G.; Turner, J. A.

    2016-04-15

    Correction for 'Sunlight absorption in water - efficiency and design implications for photoelectrochemical devices' by H. Doscher et al., Energy Environ. Sci., 2014, 7, 2951-2956.

  15. Symmetrical and anti-symmetrical coherent perfect absorption for acoustic waves

    SciTech Connect (OSTI)

    Wei, Pengjiang; Croënne, Charles; Tak Chu, Sai; Li, Jensen

    2014-03-24

    We investigate tunable acoustic absorption enabled by the coherent control of input waves. It relies on coherent perfect absorption originally proposed in optics. By designing appropriate acoustic metamaterial structures with resonating effective bulk modulus or density, we show that complete absorption of incident waves impinging on the metamaterial can be achieved for either symmetrical or anti-symmetrical inputs in the forward and backward directions. By adjusting the relative phase between the two incident beams, absorption can be tuned effectively from unity to zero, making coherent control useful in applications like acoustic modulators, noise controllers, transducers, and switches.

  16. H I ABSORPTION TOWARD H II REGIONS AT SMALL GALACTIC LONGITUDES

    SciTech Connect (OSTI)

    Jones, C.; Dickey, J. M.; Dawson, J. R.; McClure-Griffiths, N. M.; Anderson, L. D.; Bania, T. M.

    2013-09-10

    We make a comprehensive study of H I absorption toward H II regions located within |l| < 10 Degree-Sign . Structures in the extreme inner Galaxy are traced using the longitude-velocity space distribution of this absorption. We find significant H I absorption associated with the Near and Far 3 kpc Arms, the Connecting Arm, Bania's Clump 1, and the H I Tilted Disk. We also constrain the line-of-sight distances to H II regions, by using H I absorption spectra together with the H II region velocities measured by radio recombination lines.

  17. Gas cell for in situ soft X-ray transmission-absorption spectroscopy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    cell for in situ soft X-ray transmission-absorption spectroscopy of materials Previous ... Abstract: A simple gas cell design, constructed primarily from commercially available ...

  18. Simulation of Absorption Systems in Flexible and Modular Form

    Energy Science and Technology Software Center (OSTI)

    1994-09-23

    The computer code has been developed for simulation of absorption systems at steady-state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system''s components. When all the equations have been established, a mathematical solver routine is employed to solve them simultaneously. Property subroutines contained in a separate data base serve to provide thermodynamicmore » properties of the working fluids. The code is user-oriented and requires a relatively simple input containing the given operating conditions and the working fluid at each state point. the user conveys to the computer an image of the cycle by specifying the different components and their interconnections. Based on this information, the program calculates the temperature, flowrate, concentration, pressure and vapor fraction at each state point in the system and the heat duty at each unit, from which the coefficient of performance may be determined. A graphical user-interface is provided to facilitate interactive input and study of the output.« less

  19. Laser absorption spectroscopy system for vaporization process characterization and control

    SciTech Connect (OSTI)

    Galkowski, J.; Hagans, K.

    1993-09-07

    In support of the Lawrence Livermore National Laboratory`s (LLNL`s) Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program, a laser atomic absorption spectroscopy (LAS) system has been developed. This multi-laser system is capable of simultaneously measuring the line densities of {sup 238}U ground and metastable states, {sup 235}U ground and metastable states, iron, and ions at up to nine locations within the separator vessel. Supporting enrichment experiments that last over one hundred hours, this laser spectroscopy system is employed to diagnose and optimize separator system performance, control the electron beam vaporizer and metal feed systems, and provide physics data for the validation of computer models. As a tool for spectroscopic research, vapor plume characterization, vapor deposition monitoring, and vaporizer development, LLNL`s LAS laboratory with its six argon-ion-pumped ring dye lasers and recently added Ti:Sapphire and external-cavity diode-lasers has capabilities far beyond the requirements of its primary mission.

  20. Photodetector with absorbing region having resonant periodic absorption between reflectors

    DOE Patents [OSTI]

    Bryan, Robert P.; Olbright, Gregory R.; Brennan, Thomas M.; Tsao, Jeffrey Y.

    1995-02-14

    A photodetector that is responsive to a wavelength or wavelengths of interest which have heretofore been unrealized. The photodetector includes a resonant cavity structure bounded by first and second reflectors, the resonant cavity structure being resonant at the wavelength or wavelengths of interest for containing a plurality of standing waves therein. The photodetector further includes a radiation absorbing region disposed within the resonant cavity structure, the radiation absorbing region including a plurality of radiation absorbing layers spaced apart from one another by a distance substantially equal to a distance between antinodes of adjacent ones of the standing waves. Each of radiation absorbing layers is spatially positioned at a location of one of the antinodes of one of the standing waves such that radiation absorption is enhanced. The radiation absorbing layers may be either bulk layers or quantum wells includes a plurality of layers, each of which is comprised of a strained layer of InGaAs. Individual ones of the InGaAs layers are spaced apart from one another by a GaAs barrier layer.

  1. Development of a gas-fired absorption heat pump

    SciTech Connect (OSTI)

    Ohuchi, Y.

    1985-01-01

    A new absorbent-refrigerant pair suitable for heat pump heating and air-cooled cooling has been developed. Water has been selected as the refrigerant, mainly from the viewpoint of high cycle efficiency and safety, while a 1:1 mixture of lithium bromide (LiBr) and zinc chloride (ZnCl/sub 2/) by weight has been chosen as the absorbent in view of its higher solubility and affinity for water. Based on thermodynamic analysis with experimental data on properties, the new absorbent solution will give a heating COP of 1.57 and a cooling COP of 1.00 as gross values of double-effect absorption cycles, including a boiler efficiency of 80%. As a result of an experimental investigation on corrosiveness and corrosion inhibitors, promising equipment materials and inhibitors have been discovered. Prototypical units of 3.5kw (1-ton) and 35kw (10-ton) have been installed and are undergoing demonstration testing in the laboratory.

  2. Influence of laser beam profile on electromagnetically induced absorption

    SciTech Connect (OSTI)

    Cuk, S. M.; Radonjic, M.; Krmpot, A. J.; Nikolic, S. N.; Grujic, Z. D.; Jelenkovic, B. M.

    2010-12-15

    We compared, experimentally and theoretically, Hanle electromagnetically induced absorption (EIA) obtained using Gaussian and {Pi}-shaped laser beams 3 mm in diameter. The study was done by measuring the transmission of a laser locked to the F{sub g}=2{yields}F{sub e}=3 transition at the D{sub 2} line of {sup 87}Rb in a vacuum cell. EIA linewidths obtained for the two laser profiles were significantly different in the range of laser intensities 1-4 mW/cm{sup 2}. EIA with the {Pi}-shaped laser beam has a broad intensity maximum and linewidths larger than those obtained with the Gaussian beam profile. We also studied Hanle EIA by measuring the transmission of selected segments of the entire laser beam by placing a small movable aperture in front of the detector. Waveforms so obtained in Hanle EIA resonances were strongly influenced both by the radial distance of the transmitted segment from the beam center and by the radial profile of the laser beam. We show that outer regions of Gaussian beam, and central regions of the {Pi}-shaped beam generate the narrowest lines. The different behaviors of EIA owing to different beam profiles revealed by both theory and experiment indicate the importance of the radial profile of the laser beam for proper modeling of coherent effects in alkali metal vapors.

  3. Photodetector with absorbing region having resonant periodic absorption between reflectors

    DOE Patents [OSTI]

    Bryan, R.P.; Olbright, G.R.; Brennan, T.M.; Tsao, J.Y.

    1995-02-14

    A photodetector is disclosed that is responsive to a wavelength or wavelengths of interest which have heretofore been unrealized. The photodetector includes a resonant cavity structure bounded by first and second reflectors, the resonant cavity structure being resonant at the wavelength or wavelengths of interest for containing a plurality of standing waves therein. The photodetector further includes a radiation absorbing region disposed within the resonant cavity structure, the radiation absorbing region including a plurality of radiation absorbing layers spaced apart from one another by a distance substantially equal to a distance between antinodes of adjacent ones of the standing waves. Each of radiation absorbing layers is spatially positioned at a location of one of the antinodes of one of the standing waves such that radiation absorption is enhanced. The radiation absorbing layers may be either bulk layers or quantum wells includes a plurality of layers, each of which is comprised of a strained layer of InGaAs. Individual ones of the InGaAs layers are spaced apart from one another by a GaAs barrier layer. 11 figs.

  4. High power laser heating of low absorption materials

    SciTech Connect (OSTI)

    Olson, K.; Talghader, J.; Ogloza, A.; Thomas, J.

    2014-09-28

    A model is presented and confirmed experimentally that explains the anomalous behavior observed in continuous wave (CW) excitation of thermally isolated optics. Distributed Bragg Reflector (DBR) high reflective optical thin film coatings of HfO₂ and SiO₂were prepared with a very low absorption, about 7 ppm, measured by photothermal common-path interferometry. When illuminated with a 17 kW CW laser for 30 s, the coatings survived peak irradiances of 13 MW/cm², on 500 μm diameter spot cross sections. The temperature profile of the optical surfaces was measured using a calibrated thermal imaging camera for illuminated spot sizes ranging from 500 μm to 5 mm; about the same peak temperatures were recorded regardless of spot size. This phenomenon is explained by solving the heat equation for an optic of finite dimensions and taking into account the non-idealities of the experiment. An analytical result is also derived showing the relationship between millisecond pulse to CW laser operation where (1) the heating is proportional to the laser irradiance (W/m²) for millisecond pulses, (2) the heating is proportional to the beam radius (W/m) for CW, and (3) the heating is proportional to W/m∙ tan⁻¹(√(t)/m) in the transition region between the two.

  5. Quantitative infrared absorption cross sections of isoprene for atmospheric measurements

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Brauer, C. S.; Blake, T. A.; Guenther, A. B.; Sharpe, S. W.; Sams, R. L.; Johnson, T. J.

    2014-11-19

    Isoprene (C5H8, 2-methyl-1,3-butadiene) is a volatile organic compound (VOC) and is one of the primary contributors to annual global VOC emissions. Isoprene is produced primarily by vegetation as well as anthropogenic sources, and its OH- and O3-initiated oxidations are a major source of atmospheric oxygenated organics. Few quantitative infrared studies have been reported for isoprene, limiting the ability to quantify isoprene emissions via remote or in situ infrared detection. We thus report absorption cross sections and integrated band intensities for isoprene in the 600–6500 cm-1 region. The pressure-broadened (1 atmosphere N2) spectra were recorded at 278, 298, and 323 Kmore » in a 19.94 cm path-length cell at 0.112 cm-1 resolution, using a Bruker IFS 66v/S Fourier transform infrared (FTIR) spectrometer. Composite spectra are derived from a minimum of seven isoprene sample pressures, each at one of three temperatures, and the number densities are normalized to 296 K and 1 atm.« less

  6. Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns

    SciTech Connect (OSTI)

    Clark, E.A.

    1992-11-21

    Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (ABL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns.

  7. Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns

    SciTech Connect (OSTI)

    Clark, E.A.

    1992-11-21

    Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (AHL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns.

  8. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOE Patents [OSTI]

    Cassano, Anthony A.

    1985-01-01

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

  9. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    DOE Patents [OSTI]

    Cassano, A.A.

    1985-07-02

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs. 3 figs.

  10. Nonlinear bleaching, absorption, and scattering of 532-nm-irradiated plasmonic nanoparticles

    SciTech Connect (OSTI)

    Liberman, V.; Sworin, M.; Kingsborough, R. P.; Geurtsen, G. P.; Rothschild, M.

    2013-02-07

    Single-pulse irradiation of Au and Ag suspensions of nanospheres and nanodisks with 532-nm 4-ns pulses has identified complex optical nonlinearities while minimizing material damage. For all materials tested, we observe competition between saturable absorption (SA) and reverse SA (RSA), with RSA behavior dominating for intensities above {approx}50 MW/cm{sup 2}. Due to reduced laser damage in single-pulse experiments, the observed intrinsic nonlinear absorption coefficients are the highest reported to date for Au nanoparticles. We find size dependence to the nonlinear absorption enhancement for Au nanoparticles, peaking in magnitude for 80-nm nanospheres and falling off at larger sizes. The nonlinear absorption coefficients for Au and Ag spheres are comparable in magnitude. On the other hand, the nonlinear absorption for Ag disks, when corrected for volume fraction, is several times higher. These trends in nonlinear absorption are correlated to local electric field enhancement through quasi-static mean-field theory. Through variable size aperture measurements, we also separate nonlinear scattering from nonlinear absorption. For all materials tested, we find that nonlinear scattering is highly directional and that its magnitude is comparable to that of nonlinear absorption. These results indicate methods to improve the efficacy of plasmonic nanoparticles as optical limiters in pulsed laser systems.

  11. Dataset used to improve liquid water absorption models in the microwave

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Turner, David

    2015-12-14

    Two datasets, one a compilation of laboratory data and one a compilation from three field sites, are provided here. These datasets provide measurements of the real and imaginary refractive indices and absorption as a function of cloud temperature. These datasets were used in the development of the new liquid water absorption model that was published in Turner et al. 2015.

  12. VARIATIONS OF ABSORPTION TROUGHS IN THE QUASAR SDSS J125216.58+052737.7

    SciTech Connect (OSTI)

    Chen, Zhi-Fu; Qin, Yi-Ping

    2015-01-20

    In this work, we analyze the spectra of quasar J125216.58+052737.7 (z {sub em} = 1.9035) which was observed by SDSS-I/II on 2003 January 30 and by BOSS on 2011 April 2. Both the continuum and the absorption spectra of this quasar show obvious variations between the two epochs. In the SDSS-I/II spectrum, we detect 8 C IV λλ1548,1551 absorption systems, which are detected at z {sub abs} = 1.9098, 1.8948, 1.8841, 1.8770, 1.8732, 1.8635, 1.8154, and 1.7359, respectively, and one Mg II λλ2796,2803 absorption system at z {sub abs} = 0.9912. Among these absorption systems, two C IV λλ1548,1551 absorption systems at z {sub abs} = 1.9098 and 1.7359 and the Mg II λλ2796,2803 absorption system are imprinted on the BOSS spectrum as well, and have similar absorption strengths when compared to those measured from the SDSS-I/II spectrum. Three C IV λλ1548,1551 absorption systems at z {sub abs} = 1.8948, 1.8841, and 1.8770 are also detected in the BOSS spectrum, while their absorption strengths are much weaker than those measured from the SDSS-I/II spectrum; three systems at z {sub abs} = 1.8732, 1.8635, and 1.8154 disappeared from the BOSS spectrum. Based on the variability analysis, the absorption systems that disappeared and weakened are likely to be intrinsic to the quasar. If these intrinsic absorption gases are blown away from the central region of the quasar, with respect to the quasar system, the absorption systems that disappeared would have separation velocities of 3147 kms{sup –1}, 4161 km s{sup –1}, and 9241 km s{sup –1}, while the absorption systems that weakened would have separation velocities of 900 km s{sup –1}, 2011 km s{sup –1}, and 2751 km s{sup –1}. Well-coordinated variations of the six C IV λλ1548,1551 absorption systems that disappeared and weakened, occurring on a timescale of 1026.7 days at the quasar rest frame, can be interpreted as a result of global changes in the ionization state of the absorbing gas.

  13. DIFFUSE MOLECULAR CLOUD DENSITIES FROM UV MEASUREMENTS OF CO ABSORPTION

    SciTech Connect (OSTI)

    Goldsmith, Paul F.

    2013-09-10

    We use UV measurements of interstellar CO toward nearby stars to calculate the density in the diffuse molecular clouds containing the molecules responsible for the observed absorption. Chemical models and recent calculations of the excitation rate coefficients indicate that the regions in which CO is found have hydrogen predominantly in molecular form and that collisional excitation is by collisions with H{sub 2} molecules. We carry out statistical equilibrium calculations using CO-H{sub 2} collision rates to solve for the H{sub 2} density in the observed sources without including effects of radiative trapping. We have assumed kinetic temperatures of 50 K and 100 K, finding this choice to make relatively little difference to the lowest transition. For the sources having T{sup ex}{sub 10} only for which we could determine upper and lower density limits, we find (n(H{sub 2})) = 49 cm{sup -3}. While we can find a consistent density range for a good fraction of the sources having either two or three values of the excitation temperature, there is a suggestion that the higher-J transitions are sampling clouds or regions within diffuse molecular cloud material that have higher densities than the material sampled by the J = 1-0 transition. The assumed kinetic temperature and derived H{sub 2} density are anticorrelated when the J = 2-1 transition data, the J = 3-2 transition data, or both are included. For sources with either two or three values of the excitation temperature, we find average values of the midpoint of the density range that is consistent with all of the observations equal to 68 cm{sup -3} for T{sup k} = 100 K and 92 cm{sup -3} for T{sup k} = 50 K. The data for this set of sources imply that diffuse molecular clouds are characterized by an average thermal pressure between 4600 and 6800 K cm{sup -3}.

  14. Isotope Enrichment Detection by Laser Ablation - Dual Tunable Diode Laser Absorption Spectrometry

    SciTech Connect (OSTI)

    Anheier, Norman C.; Bushaw, Bruce A.

    2009-07-01

    The rapid global expansion of nuclear energy is motivating the expedited development of new safeguards technology to mitigate potential proliferation threats arising from monitoring gaps within the uranium enrichment process. Current onsite enrichment level monitoring methods are limited by poor sensitivity and accuracy performance. Offsite analysis has better performance, but this approach requires onsite hand sampling followed by time-consuming and costly post analysis. These limitations make it extremely difficult to implement comprehensive safeguards accounting measures that can effectively counter enrichment facility misuse. In addition, uranium enrichment by modern centrifugation leads to a significant proliferation threat, since the centrifuge cascades can quickly produce a significant quantity of highly enriched uranium (HEU). The Pacific Northwest National Laboratory is developing an engineered safeguards approach having continuous aerosol particulate collection and uranium isotope analysis to provide timely detection of HEU production in a low enriched uranium facility. This approach is based on laser vaporization of aerosol particulate samples, followed by wavelength tuned laser diode spectroscopy, to characterize the 235U/238U isotopic ratio by subtle differences in atomic absorption wavelengths arising from differences in each isotopes nuclear mass, volume, and spin (hyperfine structure for 235U). Environmental sampling media is introduced into a small, reduced pressure chamber, where a focused pulsed laser vaporizes a 10 to 20-m sample diameter. The ejected plasma forms a plume of atomic vapor. A plume for a sample containing uranium has atoms of the 235U and 238U isotopes present. Tunable diode lasers are directed through the plume to selectively excite each isotope and their presence is detected by monitoring absorbance signals on a shot-to-shot basis. Single-shot detection sensitivity approaching the femtogram range and abundance uncertainty less

  15. High-throughput liquid-absorption air-sampling apparatus and methods

    DOE Patents [OSTI]

    Zaromb, Solomon

    2000-01-01

    A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is <10 cm of water, usually <5 cm of water. The sampler's collection efficiency is usually >20% for vapors or airborne particulates in the 2-3.mu. range and >50% for particles larger than 4.mu.. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives.

  16. Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma

    SciTech Connect (OSTI)

    Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15

    Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

  17. Calculation tool for transported geothermal energy using two-step absorption process

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kyle Gluesenkamp

    2016-02-01

    This spreadsheet allows the user to calculate parameters relevant to techno-economic performance of a two-step absorption process to transport low temperature geothermal heat some distance (1-20 miles) for use in building air conditioning. The parameters included are (1) energy density of aqueous LiBr and LiCl solutions, (2) transportation cost of trucking solution, and (3) equipment cost for the required chillers and cooling towers in the two-step absorption approach. More information is available in the included public report: "A Technical and Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings"

  18. Transient effects on the performance of a residential solar absorption chiller

    SciTech Connect (OSTI)

    Guertin, J.M.; Wood, B.D.

    1980-01-01

    The transient performance of a commercial residential 3 ton lithium-bromide/water absorption chiller is studied. Emphasis was placed on separating the chiller response from that of the entire test facility so that its transient response could solely be observed and quantified. It was found that the entire system time response and thermal capacitance has a major impact on performance degradation due to transient operation. Isolation of the absorption chiller from system effects showed time to steady state performance to be a linear function of steady state water supply temperatures. These findings summarized in computer algorithms were used to map the integrated performance of a 3 ton absorption chiller.

  19. "Trace Analysis of Speciality and Electronic Gases," Chapter 4, "Emerging Infrared Laser Absorption Spectroscopic Techniques for Gas Analysis"

    SciTech Connect (OSTI)

    Lascola, R.; McWhorter, S.; Tittel, F.; Lewicki, R.

    2013-07-01

    This chapter covers Laser Absorption Spectroscopic Techniques and Applications of Semiconductor LAS Based Trace Gas Sensor Systems.

  20. Use Low-Grade Waste Steam to Power Absorption Chillers - Steam Tip Sheet #14

    SciTech Connect (OSTI)

    2012-01-31

    This revised AMO tip sheet on waste steam to power absorption chillers provides how-to advice for improving the system using low-cost, proven practices and technologies.

  1. Metaporous layer to overcome the thickness constraint for broadband sound absorption

    SciTech Connect (OSTI)

    Yang, Jieun; Lee, Joong Seok; Kim, Yoon Young

    2015-05-07

    The sound absorption of a porous layer is affected by its thickness, especially in a low-frequency range. If a hard-backed porous layer contains periodical arrangements of rigid partitions that are coordinated parallel and perpendicular to the direction of incoming sound waves, the lower bound of the effective sound absorption can be lowered much more and the overall absorption performance enhanced. The consequence of rigid partitioning in a porous layer is to make the first thickness resonance mode in the layer appear at much lower frequencies compared to that in the original homogeneous porous layer with the same thickness. Moreover, appropriate partitioning yields multiple thickness resonances with higher absorption peaks through impedance matching. The physics of the partitioned porous layer, or the metaporous layer, is theoretically investigated in this study.

  2. Optimizing optical absorption of TiO{sub 2} by alloying with...

    Office of Scientific and Technical Information (OSTI)

    Title: Optimizing optical absorption of TiOsub 2 by alloying with TiSsub 2 TiOsub 2 is an attractive material for photocatalytic water splitting, but its band gap is too ...

  3. Low-dimensional systems investigated by x-ray absorption spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    Title: Low-dimensional systems investigated by x-ray absorption spectroscopy: a selection of 2D, 1D and 0D cases Authors: Mino, Lorenzo ; Agostini, Giovanni ; Borfecchia, Elisa ; ...

  4. Simulation of energy absorption spectrum in NaI crystal detector...

    Office of Scientific and Technical Information (OSTI)

    Simulation of energy absorption spectrum in NaI crystal detector for multiple gamma energy using Monte Carlo method Citation Details In-Document Search Title: Simulation of energy ...

  5. Presentation of a prototype absorption boiler. The features and possible developments of the system

    SciTech Connect (OSTI)

    Meyer, M.

    1982-01-01

    Tests on an absorption-type space-heating boiler confirmed that the absorption principle holds promise as a means of recovering the heat energy in the water vapor of the combustion products at a temperature much higher than allowed in current condensation-boiler designs. The system is basically a conventional boiler with an added lithium-bromide absorption circuit. Because the absorbent separates the water from the rest of the stack gases, the condensate is less acidic - and thus not as corrosive - as that produced in other condensing systems. However, because the complex structure of the recuperator poses significant maintenance problems, the absorption heating system would probably be most practical in large multifamily or industrial space-heating applications.

  6. Photovoltaic device with increased light absorption and method for its manufacture

    DOE Patents [OSTI]

    Glatfelter, Troy; Vogeli, Craig; Call, Jon; Hammond, Ginger

    1993-07-20

    A photovoltaic cell having a light-directing optical element integrally formed in an encapsulant layer thereof. The optical element redirects light to increase the internal absorption of light incident on the photovoltaic device.

  7. United States Department of Energy large commercial absorption chiller development program

    SciTech Connect (OSTI)

    Garland, P.W.; DeVault, R.C.; Zaltash, A.

    1998-11-01

    The US Department of Energy (DOE) is working with partners from the gas cooling industry to improve energy efficiency and US competitiveness by using advanced absorption technologies that eliminate the use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), refrigerants that contribute to ozone depletion and global warming. Absorption cooling uses natural gas as the heat source, which produces much lower NO{sub x} emissions than oil- or coal-generated electricity. Gas-fired chillers also have the advantage of helping reduce peak electrical usage during summer months. To assist industry in developing advanced absorption cooling technologies, DOE sponsors the Large Commercial Chiller Development Program. The goal of the program is to improve chiller cooling efficiency by 30--50% compared with the best currently available absorption systems.

  8. High pressure effects on U L[subscript 3] x-ray absorption in...

    Office of Scientific and Technical Information (OSTI)

    High pressure effects on U Lsubscript 3 x-ray absorption in partial fluorescence yield ... Citation Details In-Document Search Title: High pressure effects on U Lsubscript 3 x-ray ...

  9. Cost reductions in absorption chillers. Final report, June 1984-May 1985

    SciTech Connect (OSTI)

    Leigh, R.W.

    1986-05-01

    Absorption chillers have great difficulty competing with the electric-driven compression alternative, due in part to modest operating efficiencies and largely to high first costs. This project is an assessment of the possibility of lowering the costs of absorption chillers dramatically by the use of low material intensity in the design of a new generation of these machines. Breakeven costs for absorption chillers, their heat exchangers and heat exchanger materials were established which will allow commercial success. Polymeric and metallic materials appropriate to particular components and which meet the cost goals were identified. A subset of these materials were tested and ordered by success in tolerating conditions and materials found in absorption chiller applications. Conceptual designs which indicate the practicality of the low material intensity approach were developed. The work reported here indicates that there is a high probability that this apporach will be successful.

  10. Infrared optical absorption in low-spin Fe 2+ -doped SrTiO 3...

    Office of Scientific and Technical Information (OSTI)

    This content will become publicly available on January 6, 2017 Title: Infrared optical absorption in low-spin Fe 2+ -doped SrTiO 3 Authors: Comes, Ryan B. ; Kaspar, Tiffany C. ; ...

  11. Enhanced Gas Absorption in the Ionic Liquid 1-n-Hexyl-3-methylimidazol...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Enhanced Gas Absorption in the Ionic Liquid 1-n-Hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)amide (hmimTfsub 2N) Confined in Silica Slit Pores: A ...

  12. Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free...

    Office of Scientific and Technical Information (OSTI)

    Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free Electron Laser: Application to Spin Crossover Dynamics Citation Details In-Document Search Title: Femtosecond X-ray...

  13. Infrared Optical Absorption in Low-spin Fe2+-doped SrTiO3 (Journal...

    Office of Scientific and Technical Information (OSTI)

    Title: Infrared Optical Absorption in Low-spin Fe2+-doped SrTiO3 Band gap engineering in ... The novel electronic states observed here offer a new avenue for band gap engineering in ...

  14. Visible Light Absorption of N-Doped TiO2 Rutile Using (LR/RT...

    Office of Scientific and Technical Information (OSTI)

    N-Doped TiO2 Rutile Using (LRRT)-TDDFT and Active Space EOMCCSD Calculations Citation Details In-Document Search Title: Visible Light Absorption of N-Doped TiO2 Rutile Using ...

  15. Method of determining pH by the alkaline absorption of carbon dioxide

    DOE Patents [OSTI]

    Hobbs, David T.

    1992-01-01

    A method for measuring the concentration of hydroxides in alkaline solutions in a remote location using the tendency of hydroxides to absorb carbon dioxide. The method includes the passing of carbon dioxide over the surface of an alkaline solution in a remote tank before and after measurements of the carbon dioxide solution. A comparison of the measurements yields the absorption fraction from which the hydroxide concentration can be calculated using a correlation of hydroxide or pH to absorption fraction.

  16. A Technical and Economic Analysis of an Innovative Two-Step Absorption

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings | Department of Energy A Technical and Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings A Technical and Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings A Technical and Economic Analysis of an Innovative

  17. On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling | Department of Energy Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling A first set of results has found that LASAR and VLPS data in the laboratory closely

  18. Neutral hydrogen absorption in the radio spectrum of PKS 0241 + 011

    SciTech Connect (OSTI)

    England, M.N.; Gottesman, S.T. )

    1990-07-01

    The detection (at about the 3 sigma level) of an absorption feature at a heliocentric velocity of 1172 km/s in the spectrum of PKS 0241 + 011 is presented. The line of sight to the quasar (z-PKS = 1.4) lies well within the optical and H I boundaries of the barred spiral galaxy NGC 1073 (z-gal = 0.004). Two other continuum sources in the field of NGC 1073 do not show any absorption features. 17 refs.

  19. Thermal emission and absorption of radiation in finite inverted-opal photonic crystals

    SciTech Connect (OSTI)

    Florescu, Marian; Stimpson, Andrew J.; Lee, Hwang; Dowling, Jonathan

    2005-09-15

    We study theoretically the optical properties of a finite inverted-opal photonic crystal. The light-matter interaction is strongly affected by the presence of the three-dimensional photonic crystal and the alterations of the light emission and absorption processes can be used to suppress or enhance the thermal emissivity and absorptivity of the dielectric structure. We investigate the influence of the absorption present in the system on the relevant band edge frequencies that control the optical response of the photonic crystal. Our study reveals that the absorption processes cause spectral broadening and shifting of the band edge optical resonances, and determine a strong reduction of the photonic band gap spectral range. Using the angular and spectral dependence of the band edge frequencies for stop bands along different directions, we argue that by matching the blackbody emission spectrum peak with a prescribed maximum of the absorption coefficient, it is possible to achieve an angle-sensitive enhancement of the thermal emission/absorption of radiation. This result opens a way to realize a frequency-sensitive and angle-sensitive photonic crystal absorbers/emitters.

  20. Enhanced light absorption by mixed source black and brown carbon particles in UK winter

    SciTech Connect (OSTI)

    Liu, Shang; Aiken, Allison C.; Gorkowski, Kyle; Dubey, Manvendra K.; Cappa, Christopher D.; Williams, Leah R.; Herndon, Scott C.; Massoli, Paola; Fortner, Edward C.; Chhabra, Puneet S.; Brooks, William A.; Onasch, Timothy B.; Jayne, John T.; Worsnop, Douglas R.; China, Swarup; Sharma, Noopur; Mazzoleni, Claudio; Xu, Lu; Ng, Nga L.; Liu, Dantong; Allan, James D.; Lee, James D.; Fleming, Zoë L.; Mohr, Claudia; Zotter, Peter; Szidat, Sönke; Prévôt, André S. H.

    2015-09-30

    We report that black carbon (BC) and light-absorbing organic carbon (brown carbon, BrC) play key roles in warming the atmosphere, but the magnitude of their effects remains highly uncertain. Theoretical modelling and laboratory experiments demonstrate that coatings on BC can enhance BC’s light absorption, therefore many climate models simply assume enhanced BC absorption by a factor of ~1.5. However, recent field observations show negligible absorption enhancement, implying models may overestimate BC’s warming. Here we report direct evidence of substantial field-measured BC absorption enhancement, with the magnitude strongly depending on BC coating amount. Increases in BC coating result from a combination of changing sources and photochemical aging processes. When the influence of BrC is accounted for, observationally constrained model calculations of the BC absorption enhancement can be reconciled with the observations. In conclusion, we find that the influence of coatings on BC absorption should be treated as a source and regionally specific parameter in climate models.

  1. Dynamics of femtosecond laser absorption of fused silica in the ablation regime

    SciTech Connect (OSTI)

    Lebugle, M. Sanner, N.; Varkentina, N.; Sentis, M.; Utéza, O.

    2014-08-14

    We investigate the ultrafast absorption dynamics of fused silica irradiated by a single 500 fs laser pulse in the context of micromachining applications. A 60-fs-resolution pump-probe experiment that measures the reflectivity and transmissivity of the target under excitation is developed to reveal the evolution of plasma absorption. Above the ablation threshold, an overcritical plasma with highly non-equilibrium conditions is evidenced in a thin layer at the surface. The maximum electron density is reached at a delay of 0.5 ps after the peak of the pump pulse, which is a strong indication of the occurrence of electronic avalanche. The results are further analyzed to determine the actual feedback of the evolution of the optical properties of the material on the pump pulse. We introduce an important new quantity, namely, the duration of absorption of the laser by the created plasma, corresponding to the actual timespan of laser absorption by inverse Bremsstrahlung. Our results indicate an increasing contribution of plasma absorption to the total material absorption upon raising the excitation fluence above the ablation threshold. The role of transient optical properties during the energy deposition stage is characterized and our results emphasize the necessity to take it into account for better understanding and control of femtosecond laser-dielectrics interaction.

  2. The polarization dependence of ?? absorptionimplications for ?-ray bursts and blazars

    SciTech Connect (OSTI)

    Bttcher, M.

    2014-11-01

    This paper presents an analysis of the dependence of the opacity for high-energy ?-rays to ?? absorption by low-energy photons on the polarization of the ?-ray and target photons. This process has so far only been considered using the polarization-averaged ?? absorption cross section. It is demonstrated that in the case of polarized ?-ray emission, subject to source-intrinsic ?? absorption by polarized target photons, this may lead to a slight overestimation of the ?? opacity by up to ?10% in the case of a perfectly ordered magnetic field. Thus, for realistic astrophysical scenarios with partially ordered magnetic fields, the use of the polarization-averaged ?? cross section is justified for practical purposes, such as estimates of minimum Doppler factors inferred for ?-ray bursts and blazars, based on ?? transparency arguments; this paper quantifies the small error incurred by the unpolarized-radiation approximation. Furthermore, it is shown that polarization-dependent ?? absorption of initially polarized ?-rays can lead to a slight increase in the polarization beyond the spectral break caused by ?? absorption. This amount is distinctly different from the change in polarization expected if the same spectral break were produced by a break in the underlying electron distribution. This may serve as a diagnostic of whether ?? absorption is relevant in sources such as ?-ray bursts and blazars where the ?-ray emission may be intrinsically highly polarized.

  3. Enhanced light absorption by mixed source black and brown carbon particles in UK winter

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Shang; Aiken, Allison C.; Gorkowski, Kyle; Dubey, Manvendra K.; Cappa, Christopher D.; Williams, Leah R.; Herndon, Scott C.; Massoli, Paola; Fortner, Edward C.; Chhabra, Puneet S.; et al

    2015-09-30

    We report that black carbon (BC) and light-absorbing organic carbon (brown carbon, BrC) play key roles in warming the atmosphere, but the magnitude of their effects remains highly uncertain. Theoretical modelling and laboratory experiments demonstrate that coatings on BC can enhance BC’s light absorption, therefore many climate models simply assume enhanced BC absorption by a factor of ~1.5. However, recent field observations show negligible absorption enhancement, implying models may overestimate BC’s warming. Here we report direct evidence of substantial field-measured BC absorption enhancement, with the magnitude strongly depending on BC coating amount. Increases in BC coating result from a combinationmore » of changing sources and photochemical aging processes. When the influence of BrC is accounted for, observationally constrained model calculations of the BC absorption enhancement can be reconciled with the observations. In conclusion, we find that the influence of coatings on BC absorption should be treated as a source and regionally specific parameter in climate models.« less

  4. High-throughput liquid-absorption preconcentrator sampling methods

    DOE Patents [OSTI]

    Zaromb, Solomon (95706 William Dr., Hinsdale, IL 60521)

    1994-01-01

    A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

  5. High-throughput liquid-absorption preconcentrator sampling methods

    DOE Patents [OSTI]

    Zaromb, S.

    1994-07-12

    A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis. 12 figs.

  6. Force-controlled absorption in a fully-nonlinear numerical wave tank

    SciTech Connect (OSTI)

    Spinneken, Johannes Christou, Marios; Swan, Chris

    2014-09-01

    An active control methodology for the absorption of water waves in a numerical wave tank is introduced. This methodology is based upon a force-feedback technique which has previously been shown to be very effective in physical wave tanks. Unlike other methods, an a-priori knowledge of the wave conditions in the tank is not required; the absorption controller being designed to automatically respond to a wide range of wave conditions. In comparison to numerical sponge layers, effective wave absorption is achieved on the boundary, thereby minimising the spatial extent of the numerical wave tank. In contrast to the imposition of radiation conditions, the scheme is inherently capable of absorbing irregular waves. Most importantly, simultaneous generation and absorption can be achieved. This is an important advance when considering inclusion of reflective bodies within the numerical wave tank. In designing the absorption controller, an infinite impulse response filter is adopted, thereby eliminating the problem of non-causality in the controller optimisation. Two alternative controllers are considered, both implemented in a fully-nonlinear wave tank based on a multiple-flux boundary element scheme. To simplify the problem under consideration, the present analysis is limited to water waves propagating in a two-dimensional domain. The paper presents an extensive numerical validation which demonstrates the success of the method for a wide range of wave conditions including regular, focused and random waves. The numerical investigation also highlights some of the limitations of the method, particularly in simultaneously generating and absorbing large amplitude or highly-nonlinear waves. The findings of the present numerical study are directly applicable to related fields where optimum absorption is sought; these include physical wavemaking, wave power absorption and a wide range of numerical wave tank schemes.

  7. A split imaging spectrometer for temporally and spatially resolved titanium absorption spectroscopy

    SciTech Connect (OSTI)

    Hager, J. D. Lanier, N. E.; Kline, J. L.; Flippo, K. A.; Bruns, H. C.; Schneider, M.; Saculla, M.; McCarville, T.

    2014-11-15

    We present a temporally and a spatially resolved spectrometer for titanium x-ray absorption spectroscopy along 2 axial symmetric lines-of-sight. Each line-of-sight of the instrument uses an elliptical crystal to acquire both the 2p and 3p Ti absorption lines on a single, time gated channel of the instrument. The 2 axial symmetric lines-of-sight allow the 2p and 3p absorption features to be measured through the same point in space using both channels of the instrument. The spatially dependent material temperature can be inferred by observing the 2p and the 3p Ti absorption features. The data are recorded on a two strip framing camera with each strip collecting data from a single line-of-sight. The design is compatible for use at both the OMEGA laser and the National Ignition Facility. The spectrometer is intended to measure the material temperature behind a Marshak wave in a radiatively driven SiO{sub 2} foam with a Ti foam tracer. In this configuration, a broad band CsI backlighter will be used for a source and the Ti absorption spectrum measured.

  8. Millimeter-Wave Absorption as a Quality Control Tool for M-Type Hexaferrite Nanopowders

    SciTech Connect (OSTI)

    McCloy, John S.; Korolev, Konstantin A.; Crum, Jarrod V.; Afsar, Mohammed N.

    2013-01-01

    Millimeter wave (MMW) absorption measurements have been conducted on commercial samples of large (micrometer-sized) and small (nanometer-sized) particles of BaFe12O19 and SrFe12O19 using a quasi-optical MMW spectrometer and a series of backwards wave oscillators encompassing the 30-120 GHz range. Effective anisotropy of the particles calculated from the resonant absorption frequency indicates lower overall anisotropy in the nano-particles. Due to their high magnetocrystalline anisotropy, both BaFe12O19 and SrFe12O19 are expected to have spin resonances in the 45-55 GHz range. Several of the sampled BaFe12O19 powders did not have MMW absorptions, so they were further investigated by DC magnetization and x-ray diffraction to assess magnetic behavior and structure. The samples with absent MMW absorption contained primarily iron oxides, suggesting that MMW absorption could be used for quality control in hexaferrite powder manufacture.

  9. Refractive index and absorption detector for liquid chromatography based on Fabry-Perot interferometry

    DOE Patents [OSTI]

    Yeung, Edward S.; Woodruff, Steven D.

    1984-06-19

    A refractive index and absorption detector for liquid chromatography. It is based in part on a Fabry-Perot interferometer and is used for the improved detection of refractive index and absorption. It includes a Fabry-Perot interferometer having a normally fixed first partially reflecting mirror and a movable second partially reflecting mirror. A chromatographic flow-cell is positioned between the mirrors along the optical axis of a monochromatic laser beam passing through the interferometer. A means for deriving information about the interference fringes coming out of the interferometer is used with a mini-computer to compute the refractive index of the specimen injected into the flow cell. The minicomputer continuously scans the interferometer for continuous refractive index readings and outputs the continuous results of the scans on a chart recorder. The absorption of the specimen can concurrently be scanned by including a second optical path for an excitation laser which will not interfere with the first laser, but will affect the specimen so that absorption properties can be detected. By first scanning for the refractive index of the specimen, and then immediately adding the excitation laser and subsequently scanning for the refractive index again, the absorption of the specimen can be computed and recorded.

  10. Refractive index and absorption detector for liquid chromatography based on Fabry-Perot interferometry

    DOE Patents [OSTI]

    Yeung, E.S.; Woodruff, S.D.

    1984-06-19

    A refractive index and absorption detector are disclosed for liquid chromatography. It is based in part on a Fabry-Perot interferometer and is used for the improved detection of refractive index and absorption. It includes a Fabry-Perot interferometer having a normally fixed first partially reflecting mirror and a movable second partially reflecting mirror. A chromatographic flow-cell is positioned between the mirrors along the optical axis of a monochromatic laser beam passing through the interferometer. A means for deriving information about the interference fringes coming out of the interferometer is used with a mini-computer to compute the refractive index of the specimen injected into the flow cell. The minicomputer continuously scans the interferometer for continuous refractive index readings and outputs the continuous results of the scans on a chart recorder. The absorption of the specimen can concurrently be scanned by including a second optical path for an excitation laser which will not interfere with the first laser, but will affect the specimen so that absorption properties can be detected. By first scanning for the refractive index of the specimen, and then immediately adding the excitation laser and subsequently scanning for the refractive index again, the absorption of the specimen can be computed and recorded. 10 figs.

  11. LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

    DOE Patents [OSTI]

    Ko, Suk M.

    1980-01-01

    This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

  12. Anisotropy of two-photon absorption and free-carrier effect in nonpolar GaN

    SciTech Connect (OSTI)

    Fang, Yu; Zhou, Feng; Yang, Junyi; Wu, Xingzhi; Xiao, Zhengguo; Li, Zhongguo; Song, Yinglin

    2015-03-30

    We reported a systematic study about the anisotropic optical nonlinearities in bulk m-plane and a-plane GaN crystals by Z-scan and pump-probe with phase object methods under picosecond at 532 nm. The two-photon absorption coefficient, which was measured as a function of polarization angle, exhibited oscillation curves with a period of π/2, indicating a highly polarized optical third-order nonlinearity in both nonpolar GaN samples. Furthermore, free-carrier absorption revealed stronger hole-related absorption for E⊥c than for E//c probe polarization. In contrast, free-carrier refraction was found almost isotropic due to electron-related refraction in the isotropic conduction bands.

  13. Using laser absorption spectroscopy to monitor composition and physical properties of metal vapors

    SciTech Connect (OSTI)

    Berzins, L.V.

    1993-09-03

    The Atomic Vapor Laser Isotope Separation (AVLIS) program has been using laser absorption spectroscopy to monitor vapor densities for over 15 years. Laser absorption spectroscopy has proven itself to be an accurate and reliable method to monitor both density and composition. During this time the diagnostic has moved from a research tool toward a robust component of a process control system. The hardware used for this diagnostic is discussed elsewhere at this symposium. This paper describes how the laser absorption spectroscopy diagnostic is used as a component of a process control system as well as supplying detailed measurements on vapor densities, composition, flow velocity, internal and kinetic temperatures, and constituent distributions. Examples will be drawn from the uranium AVLIS program. In addition potential applications such as composition control in the production of metal matrix composites or aircraft alloys will be discussed.

  14. Mode conversion and absorption of fast waves at high ion cyclotron harmonics in inhomogeneous magnetic fields

    SciTech Connect (OSTI)

    Cho, Suwon; Kwak, Jong-Gu

    2014-04-15

    The propagation and absorption of high harmonic fast waves is of interest for non-inductive current drives in fusion experiments. The fast wave can be coupled with the ion Bernstein wave that propagates in the high magnetic field side of an ion cyclotron harmonic resonance layer. This coupling and the absorption are analyzed using the hot plasma dispersion relation and a wave equation that was converted from an approximate dispersion relation for the case where λ{sub i}=k{sub ⊥}{sup 2}ρ{sub i}{sup 2}/2≳1 (where k{sub ⊥} is the perpendicular wave number and ρ{sub i} is the ion Larmor radius). It is found that both reflection and conversion may occur near the harmonic resonance layer but that they decrease rapidly, giving rise to a sharp increase in the absorption as the parallel wave number increases.

  15. An improved absorption generator for solar-thermal powered heat pumps. Part 2: Energy and economics

    SciTech Connect (OSTI)

    Fineblum, S.

    1997-12-31

    Solar heated absorption chiller installations have been very expensive for their rating. To enhance collector thermal efficiency the liquid flowing within the collectors must be kept as cool as possible. However, there is also a need to operate the absorption reported earlier. The compromise usually results in poor collector efficiency as well as a relatively poor specific chiller effect. The proposed vortex generator permits a heat pump to operate efficiently with relatively low temperature solar heated fluid (70--80 C). As a result, the collectors are cooler and more efficient. As noted in Part 1, the specific heat pumping capacity is about 27% greater than conventional systems operating at the same reduced generator temperatures. Therefore, a smaller, less expensive chiller is required. The reduced investment in solar arrays and absorption chillers is estimated along with a range of paybacks.

  16. Dynamic performance testing of prototype 3 ton air-cooled carrier absorption chiller

    SciTech Connect (OSTI)

    Borst, R.R.; Wood, B.D.

    1985-05-01

    The performance of a prototype 3 ton cooling capacity air-cooled lithium bromide/water absorption chiller was tested using an absorption chiller test facility which was modified to expand its testing capabilities to include air-cooled chillers in addition to water-cooled chillers. Temperatures of the three externally supplied fluid loops: hot water, chilled water, and cooling air, were varied in order to determine the effects this would have on the two principal measures of chiller performance: cooling capacity and thermal coefficient of performance (COP). A number of interrelated factors were identified as contributing to less than expected performance. For comparison, experimental correlations of other investigators for this and other similar absorption chillers are presented. These have been plotted as both contour and three-dimensional performance maps in order to more clearly show the functional dependence of the chiller performance on the fluid loop temperatures.

  17. Improving the performance of ammonia-water absorption cycles using salt additives and membranes

    SciTech Connect (OSTI)

    Ibrahim, O.M.; Barnett, S.M.; Balamuru, V.G.

    1997-12-31

    This paper proposes a new design of an ammonia-water absorption refrigeration cycle for low-temperature heat sources such as solar energy and waste heat. The proposed cycle uses a salt additive to shift the chemical equilibrium toward more effective separation of ammonia molecules from aqueous solution (i.e., salting out). Since salt additives can affect all aspects of the absorption cycle, membranes have been chosen to control the flow of ions in the cycle and limit their effects to the generation side. This paper describes an absorption cycle that uses membrane separation processes, such as reverse osmosis, dialysis, and electrodialysis. To optimize the performance of the cycle, however, the membranes and salts must be carefully chosen.

  18. Absorption spectrum and solar photodissociation of gaseous nitrous acid in the actinic wavelength region

    SciTech Connect (OSTI)

    Vasudev, R. )

    1990-11-01

    The absorption cross section of gaseous nitrous acid (HONO) in the actinic wavelength region ({lambda} {ge} 290 nm) of the solar radiation is mapped through laser photodissociation experiments, HONO is photodissociated by a tunable ultraviolet beam, and the OH product is monitored through fluorescence induced by a frequency-double dye laser. The absorption of HONO is mapped by scanning the photolysis wavelength. Since this technique yields relative cross-sections, the authors calibrate the measurements with previous measurements of absolute cross-section at 354 nm (because there is reasonable agreement among previous measurements at this wavelength). The present experimental approach is insensitive to the presence of NO{sub 2}, which apparently contributed to inaccuracies in some of the previous conventional measurements on HONO absorption.

  19. On the dynamic and static manifestation of molecular absorption in thin films probed by a microcantilever

    SciTech Connect (OSTI)

    Finot, Eric; Fabre, Arnaud; Passian, Ali; Thundat, Thomas

    2014-03-01

    Mechanical resonators shaped like microcantilevers have been demonstrated as a platform for very sensitive detection of chemical and biological analytes. However, its use as an analytical tool will require fundamental understanding of the molecular absorption-induced effects in the static and dynamic sensor response. The effect of absorption-induced surface stress on the microcantilever response is here investigated using palladium hydride formation. It is shown that the resonance and deformation states of the cantilever monitored simultaneously exhibit excellent correlation with the phase of the hydride formation. However, the associated frequency shifts and quasistatic bending are observed to be independent during solid solution phase. Importantly, absorption-induced changes in the elastic parameters of the palladium film are found to play a dominant role in the static and dynamic response. The presented results help in discerning the parameters that control the cantilever response as well as the relationships between these parameters.

  20. Effect of vitrification temperature upon the solar average absorptance properties of Pyromark Series 2500 black paint

    SciTech Connect (OSTI)

    Nelson, C.; Mahoney, A.R.

    1986-06-01

    A significant drop in production efficiency has occurred over time at the Solar One facility at Barstow, California, primarily as a result of the degradation of the Pyromark Series 2500 black paint used as the absorptive coating on the receiver panels. As part of the investigation of the problem, the solar-averaged adsorptance properties of the paint were determined as a function of vitrification temperature, since it is known that a significant amount of the panel surface area at Solar One was vitrified at temperatures below those recommended by the paint manufacturer (540/sup 0/C, 1000/sup 0/F). Painted samples initially vitrified at 230/sup 0/C (450/sup 0/F), 315/sup 0/C (600/sup 0/F), 371/sup 0/C (700/sup 0/F), and 480/sup 0/C (900/sup 0/F) exhibited significantly lower solar-averaged absorptance values (0.02 absorptance units) compared to samples vitrified at 540/sup 0/C (1000/sup 0/F). Thus, Solar One began its service life below optimal levels. After 140 h of thermal aging at 370/sup 0/C (700/sup 0/F) and 540/sup 0/C (1000/sup 0/F), all samples regardless of their initial vitrification temperatures, attained the same solar-averaged absorptance value (..cap alpha../sub s/ = 0.973). Therefore, both the long-term low-temperature vitrification and the short-term high-temperature vitrification can be used to obtain optimal or near-optimal absorptance of solar flux. Futher thermal aging of vitrified samples did not result in paint degradation, clearly indicating that high solar flux is required to produce this phenomenon. The panels at Solar One never achieved optimal absorptance because their exposure to high solar flux negated the effect of long-term low-temperature vitrification during operation. On future central receiver projects, every effort should be made to properly vitrify the Pyromark coating before its exposure to high flux conditions.

  1. An experimental investigation of the mass-transfer mechanisms in sulfur dioxide absorption in lime solutions

    SciTech Connect (OSTI)

    Markussen, J.M.

    1991-04-01

    The experiments were performed at gas temperatures from 24 to 114C using a wetted-wall column apparatus with SO{sub 2} concentrations ranging from 1800 to 7350 ppM, calcium concentrations of 2.82 {times} 10{sup {minus}6} to 1. 25 {times} 10{sup {minus}5} gmol/cm{sup 3}, and column heights of 14 to 29 cm. Inlet SO{sub 2} content had a significant effect on rate of SO{sub 2} absorption, with the average absorption flux increasing with increasing SO{sub 2} gas concentration. Increasing gas temperature did not significantly affect the rate of SO{sub 2} absorption. Presence of lime in solution enhanced the average SO{sub 2} absorption flux and appeared to maintain the SO{sub 2} absorption capacity of the liquid, thereby negating the effect of decreasing SO{sub 2} solubility in water with increasing temperature. Slight increases in both the system`s gas-phase resistances and enhancement factors were observed with increasing gas temperature. Under the conditions studied, the mass-transfer resistance in the SO{sub 2}-lime solution system was predominantly liquid-phase controlled, with observed gas-phase resistances ranging up to 42% of total. Comparison to literature shows that the system mass-transfer mechanism can be dominated by either the gas-phase resistance or the liquid-phase resistance, depending upon the gas-liquid contact times. Thus, results support the need to incorporate both gas- and liquid-phase mass-transfer resistances when modeling the absorption of SO{sub 2} in lime solutions and lime slurries, such as that occurring in the constant rate drying stage of the spray drying flue gas desulfurization process.

  2. An experimental investigation of the mass-transfer mechanisms in sulfur dioxide absorption in lime solutions

    SciTech Connect (OSTI)

    Markussen, J.M.

    1991-04-01

    The experiments were performed at gas temperatures from 24 to 114C using a wetted-wall column apparatus with SO[sub 2] concentrations ranging from 1800 to 7350 ppM, calcium concentrations of 2.82 [times] 10[sup [minus]6] to 1. 25 [times] 10[sup [minus]5] gmol/cm[sup 3], and column heights of 14 to 29 cm. Inlet SO[sub 2] content had a significant effect on rate of SO[sub 2] absorption, with the average absorption flux increasing with increasing SO[sub 2] gas concentration. Increasing gas temperature did not significantly affect the rate of SO[sub 2] absorption. Presence of lime in solution enhanced the average SO[sub 2] absorption flux and appeared to maintain the SO[sub 2] absorption capacity of the liquid, thereby negating the effect of decreasing SO[sub 2] solubility in water with increasing temperature. Slight increases in both the system's gas-phase resistances and enhancement factors were observed with increasing gas temperature. Under the conditions studied, the mass-transfer resistance in the SO[sub 2]-lime solution system was predominantly liquid-phase controlled, with observed gas-phase resistances ranging up to 42% of total. Comparison to literature shows that the system mass-transfer mechanism can be dominated by either the gas-phase resistance or the liquid-phase resistance, depending upon the gas-liquid contact times. Thus, results support the need to incorporate both gas- and liquid-phase mass-transfer resistances when modeling the absorption of SO[sub 2] in lime solutions and lime slurries, such as that occurring in the constant rate drying stage of the spray drying flue gas desulfurization process.

  3. Systems having optical absorption layer for mid and long wave infrared and methods for making the same

    DOE Patents [OSTI]

    Kuzmenko, Paul J

    2013-10-01

    An optical system according to one embodiment includes a substrate; and an optical absorption layer coupled to the substrate, wherein the optical absorption layer comprises a layer of diamond-like carbon, wherein the optical absorption layer absorbs at least 50% of mid wave infrared light (3-5 .mu.m wavelength) and at least 50% of long wave infrared light (8-13 .mu.m wavelength). A method for applying an optical absorption layer to an optical system according to another embodiment includes depositing a layer of diamond-like carbon of an optical absorption layer above a substrate using plasma enhanced chemical vapor deposition, wherein the optical absorption layer absorbs at least 50% of mid wave infrared light (3-5 .mu.m wavelength) and at least 50% of long wave infrared light (8-13 .mu.m wavelength). Additional systems and methods are also presented.

  4. Optimizing and calibrating a mode-mismatched thermal lens experiment for low absorption measurement

    SciTech Connect (OSTI)

    Marcano, Aristides; Cabrera, Humberto; Guerra, Mayamaru; Cruz, Renato A.; Jacinto, Carlos; Catunda, Tomaz

    2006-07-15

    We describe a calibrated two-beam mode-mismatched thermal lens experiment aimed at determination of the absorption coefficient and the photothermal parameters of a nearly transparent material. The use of a collimated probe beam in the presence of a focused excitation beam optimizes the thermal lens experiment. The signal becomes independent from the Rayleigh parameters and waist positions of the beams. We apply this method to determine the absolute value of the thermal diffusivity and absorption coefficient of distilled water at 533 nm.

  5. Approaching total absorption at near infrared in a large area monolayer graphene by critical coupling

    SciTech Connect (OSTI)

    Liu, Yonghao; Chadha, Arvinder; Zhao, Deyin; Shuai, Yichen; Menon, Laxmy; Yang, Hongjun; Zhou, Weidong; Piper, Jessica R.; Fan, Shanhui; Jia, Yichen; Xia, Fengnian; Ma, Zhenqiang

    2014-11-03

    We demonstrate experimentally close to total absorption in monolayer graphene based on critical coupling with guided resonances in transfer printed photonic crystal Fano resonance filters at near infrared. Measured peak absorptions of 35% and 85% were obtained from cavity coupled monolayer graphene for the structures without and with back reflectors, respectively. These measured values agree very well with the theoretical values predicted with the coupled mode theory based critical coupling design. Such strong light-matter interactions can lead to extremely compact and high performance photonic devices based on large area monolayer graphene and other twodimensional materials.

  6. Method of determining pH by the alkaline absorption of carbon dioxide

    DOE Patents [OSTI]

    Hobbs, D.T.

    1992-10-06

    A method is described for measuring the concentration of hydroxides in alkaline solutions in a remote location using the tendency of hydroxides to absorb carbon dioxide. The method includes the passing of carbon dioxide over the surface of an alkaline solution in a remote tank before and after measurements of the carbon dioxide solution. A comparison of the measurements yields the absorption fraction from which the hydroxide concentration can be calculated using a correlation of hydroxide or pH to absorption fraction. 2 figs.

  7. Optical absorption in B{sub 13} cluster: A time-dependent density functional approach

    SciTech Connect (OSTI)

    Shinde, Ravindra; Tayade, Meenakshi

    2013-02-05

    The linear optical absorption spectra of three isomers of planar boron cluster B{sub 13} are calculated using time-dependent spin-polarized density functional approach. The geometries of these cluster are optimized at the B3LYP/6-311+G* level of theory. Even though the isomers are almost degenerate, the calculated spectra are quite different, indicating a strong structure-property relationship. Therefore, these computed spectra can be used in the photo-absorption experiments to distinguish between different isomers of a cluster.

  8. Enhanced anomalous photo-absorption from TiO{sub 2} nanostructures

    SciTech Connect (OSTI)

    Solanki, Vanaraj; Majumder, Subrata; Mishra, Indrani; Varma, Shikha; Dash, P.; Singh, C.; Kanjilal, D.

    2014-03-28

    Two dimensional nanostructures have been created on the rutile TiO{sub 2} (110) surfaces via ion irradiation technique. Enhanced anomalous photo- absorption response is displayed, where nanostructures of 15?nm diameter with 0.5?nm height, and not the smaller nanostructures with larger surface area, delineate highest absorbance. Comprehensive investigations of oxygen vacancy states, on ion- irradiated surfaces, display a remarkable result that the number of vacancies saturates for higher fluences. A competition between the number of vacancy sites on the nanostructure in conjunction with its size is responsible for the observed anomalous photo-absorption.

  9. Enhancement of near-infrared absorption in graphene with metal gratings

    SciTech Connect (OSTI)

    Zhao, B.; Zhang, Z. M., E-mail: zhuomin.zhang@me.gatech.edu [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Zhao, J. M. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); School of Energy Science and Engineering, Harbin Institute of Technology, Harbin (China)

    2014-07-21

    Graphene has been demonstrated as a good candidate for ultrafast optoelectronic devices. However, graphene is essentially transparent in the visible and near infrared with an absorptivity of 2.3%, which has largely limited its application in photon detection. This Letter demonstrates that the absorptance in a monatomic graphene layer can be greatly enhanced to nearly 70%, thanks to the localized strong electric field resulting from magnetic resonances in deep metal gratings. Furthermore, the resonance frequency is essentially not affected by the additional graphene layer. The method presented here may benefit the design of next-generation graphene-based optical and optoelectronic devices.

  10. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOE Patents [OSTI]

    Cremers, David A.; Keller, Richard A.

    1985-01-01

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10.sup.-5 cm.sup.-1 has been demonstrated using this technique.

  11. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOE Patents [OSTI]

    Cremers, D.A.; Keller, R.A.

    1985-10-01

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10[sup [minus]5] cm[sup [minus]1] has been demonstrated using this technique. 6 figs.

  12. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOE Patents [OSTI]

    Cremers, D.A.; Keller, R.A.

    1982-06-08

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be rlated to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10/sup -5/ cm/sup -1/ has been demonstrated using this technique.

  13. Non-degenerate two-photon absorption in silicon waveguides: Analytical and experimental study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Yanbing; Husko, Chad; Lefrancois, Simon; Rey, Isabella H.; Krauss, Thomas F.; Schrder, Jochen; Eggleton, Benjamin J.

    2015-06-22

    We theoretically and experimentally investigate the nonlinear evolution of two optical pulses in a silicon waveguide. We provide an analytic solution for the weak probe wave undergoing non-degenerate two-photon absorption (TPA) from the strong pump. At larger pump intensities, we employ a numerical solution to study the interplay between TPA and photo-generated free carriers. We develop a simple and powerful approach to extract and separate out the distinct loss contributions of TPA and free-carrier absorption from readily available experimental data. Our analysis accounts accurately for experimental results in silicon photonic crystal waveguides.

  14. Capillary absorption spectrometer and process for isotopic analysis of small samples

    DOE Patents [OSTI]

    Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.; Moran, James J.; Newburn, Matthew K.; Blake, Thomas A.

    2016-03-29

    A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The method also permits sampling in vivo permitting real-time ambient studies of microbial communities.

  15. Non-degenerate two-photon absorption in silicon waveguides. Analytical and experimental study

    SciTech Connect (OSTI)

    Zhang, Yanbing; Husko, Chad; Lefrancois, Simon; Rey, Isabella H.; Krauss, Thomas F.; Schröder, Jochen; Eggleton, Benjamin J.

    2015-06-22

    We theoretically and experimentally investigate the nonlinear evolution of two optical pulses in a silicon waveguide. We provide an analytic solution for the weak probe wave undergoing non-degenerate two-photon absorption (TPA) from the strong pump. At larger pump intensities, we employ a numerical solution to study the interplay between TPA and photo-generated free carriers. We develop a simple and powerful approach to extract and separate out the distinct loss contributions of TPA and free-carrier absorption from readily available experimental data. Our analysis accounts accurately for experimental results in silicon photonic crystal waveguides.

  16. Method for measuring changes in light absorption of highly scattering media

    DOE Patents [OSTI]

    Bigio, Irving J.; Johnson, Tamara M.; Mourant, Judith R.

    2002-01-01

    The noninvasive measurement of variations in absorption that are due to changes in concentrations of biochemically relevant compounds in tissue is important in many clinical settings. One problem with such measurements is that the pathlength traveled by the collected light through the tissue depends on the scattering properties of the tissue. It is demonstrated, using both Monte Carlo simulations and experimental measurements, that for an appropriate separation between light-delivery and light-collection fibers, the pathlength of the collected photons is insensitive to scattering parameters for the range of parameters typically found in tissue. This is important for developing rapid, noninvasive, inexpensive, and accurate methods for measuring absorption changes in tissue.

  17. Neutral hydrogen absorption by galaxies and implications for the soft X-ray background

    SciTech Connect (OSTI)

    Corbelli, E.; Schneider, S.E. Massachusetts Univ., Amherst )

    1990-06-01

    Results are presented from a search for neutral hydrogen absorption in the 21-cm spectra of 59 radio continuum sources in the proximity of spiral and lenticular galaxies using the Arecibo radio telescope. Five galaxies showed possible but uncertain absorption. For the 54 other sources, the column density of the neutral hydrogen in the intervening material is well below 2 x 10 to the 19th/cu cm or the spin temperature is at least one order of magnitude above the microwave background temperature. For these cases, subthermal effects are not hiding appreciable amounts of neutral hydrogen. 47 refs.

  18. Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP Applications, April 2005

    Office of Energy Efficiency and Renewable Energy (EERE)

    Development status of air-cooled lithium bromide (LiBr)-water absorption chillers for cooling, heating, and power (CHP) system applications in light-commercial buildings.

  19. A narrow window of Rabi frequency for competition between electromagnetically induced transparency and Raman absorption

    SciTech Connect (OSTI)

    Chang, Ray-Yuan; Fang, Wei-Chia; Lee, Ming-Tsung; He, Zong-Syun; Ke, Bai-Cian; Lee, Yi-Chi; Tsai, Chin-Chun

    2010-01-15

    This investigation clarifies the transition phenomenon between the electromagnetically induced transparency (EIT) and Raman absorption in a ladder-type system of Doppler-broadened cesium vapor. A competition window of this transition was found to be as narrow as 2 MHz defined by the probe Rabi frequency. For a weak probe, the spectrum of EIT associated with quantum interference suggests that the effect of the Doppler velocity on the spectrum is negligible. When the Rabi frequency of the probe becomes comparable with the effective decay rate, an electromagnetically induced absorption (EIA) dip emerges at the center of the power broadened EIT peak. While the Rabi frequency of the probe exceeds the effective decay rate, decoherence that is generated by the intensified probe field occurs and Raman absorption dominates the interaction process, yielding a pure absorption spectrum; the Doppler velocity plays an important role in the interaction. A theory that is based on density matrix simulation, with or without the Doppler effect, can qualitatively fit the experimental data. In this work, the coherence of atom-photon interactions is created or destroyed using the probe Rabi frequency as a decoherence source.

  20. Use of radial symmetry for the calculation of cylindrical absorption coefficients and optimal capillary loadings

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khalifah, Peter

    2015-02-01

    The problem of numerically evaluating absorption correction factors for cylindrical samples has been revisited using a treatment that fully takes advantage of the sample symmetry. It is shown that the path lengths for all points within the sample at all possible diffraction angles can be trivially determined once the angle-dependent distance distribution for a single line of points is calculated. This provides advantages in both computational efficiency and in gaining an intuitive understanding of the effects of absorption on diffraction data. A matrix of absorption coefficients calculated for µR products between 0 and 20 for diffraction angles θD of 0°more » to 90° were used to examine the influence of (1) capillary diameter and of (2) sample density on the overall scattered intensity as a function of diffraction angle, where µ is the linear absorption coefficient for the sample and R is the capillary radius. Based on this analysis, the optimal sample loading for a capillary experiment to maximize diffraction at angles of 0 – 50° is in general expected to be achieved when the maximum radius capillary compatible with the beam is used, and when the sample density is adjusted to be 3/(4µR) of its original density.« less

  1. Use of radial symmetry for the calculation of cylindrical absorption coefficients and optimal capillary loadings

    SciTech Connect (OSTI)

    Khalifah, Peter

    2015-02-01

    The problem of numerically evaluating absorption correction factors for cylindrical samples has been revisited using a treatment that fully takes advantage of the sample symmetry. It is shown that the path lengths for all points within the sample at all possible diffraction angles can be trivially determined once the angle-dependent distance distribution for a single line of points is calculated. This provides advantages in both computational efficiency and in gaining an intuitive understanding of the effects of absorption on diffraction data. A matrix of absorption coefficients calculated for µR products between 0 and 20 for diffraction angles θD of 0° to 90° were used to examine the influence of (1) capillary diameter and of (2) sample density on the overall scattered intensity as a function of diffraction angle, where µ is the linear absorption coefficient for the sample and R is the capillary radius. Based on this analysis, the optimal sample loading for a capillary experiment to maximize diffraction at angles of 0 – 50° is in general expected to be achieved when the maximum radius capillary compatible with the beam is used, and when the sample density is adjusted to be 3/(4µR) of its original density.

  2. Cycle simulation of the low-temperature triple-effect absorption chiller with vapor compression unit

    SciTech Connect (OSTI)

    Kim, J.S.; Lee, H.

    1999-07-01

    The construction of a triple-effect absorption chiller machine using the lithium bromide-water solution as a working fluid is strongly limited by corrosion problems caused by the high generator temperature. In this work, three new cycles having the additional vapor compression units were suggested in order to lower the generator temperature of a triple-effect absorption chiller. Each new cycle has one compressor located at the different position which was used to elevate the pressure of the refrigerant vapor. Computer simulations were carried out in order to examine both the basic triple-effect cycle and three new cycles. All types of triple-effect absorption chiller cycles were found to be able to lower the temperature of high-temperature generator to the more favorable operation range. The COPs of three cycles calculated by considering the additional compressor works showed a small level of decrease or increase compared with that of the basic triple-effect cycle. Consequently, a low-temperature triple-effect absorption chiller can be possibly constructed by adapting one of three new cycles. A great advantage of these new cycles over the basic one is that the conventionally used lithium bromide-water solution can be successfully used as a working fluid without the danger of corrosion.

  3. Enhanced heat transfer tubes for film absorbers of absorption chiller/heater

    SciTech Connect (OSTI)

    Sasaki, Naoe; Nosetani, Tadashi; Furukawa, Masahiro; Kaneko, Toshiyuki

    1995-12-31

    Absorption chiller/heaters using non-CFC refrigerants are attracting attention as environmentally friendly energy systems. As the refrigerant/absorbent pair, the water/lithium bromide aqueous solution pair is preferably used for most absorption chiller/heaters in Japan. Absorption chiller/heaters, mainly used as water chillers and air-conditioners, are commercially available at least for unit cooling capacities above 60 kW. In absorption chiller/heaters, the absorber must be made compact, because the absorber has the largest heat transfer area of the four primary heat exchangers in the system: the evaporator, absorber, regenerator and condenser. Although a great amount of information is available on the evaporator and condenser, the same type of information concerning the absorber is lacking. This paper introduces two kinds of double fluted tubes called Arm tubs and Floral tubes for film absorbers. Arm tubes are manufactured using a two-pass drawbench process, while Floral tubes are made using a single pass drawbench process. The experiments using a lithium bromide aqueous solution with the addition of 250 ppm n-octyl alcohol as the surfactant showed that Arm tubes and Floral tubes had about 40% higher heat transfer performance than plain tubes. Therefore, Floral tubes are expected to realize a high performance at low cost. Furthermore, the optimization of the number of grooves on the outside of the tubes is also described here.

  4. Absorptivity of semiconductors used in the production of solar cell panels

    SciTech Connect (OSTI)

    Kosyachenko, L. A. Grushko, E. V.; Mikityuk, T. I.

    2012-04-15

    The dependence of the absorptivity of semiconductors on the thickness of the absorbing layer is studied for crystalline silicon (c-Si), amorphous silicon (a-Si), cadmium telluride (CdTe), copper indium diselenide (CuInSe{sub 2}, CIS), and copper gallium diselenide (CuGaSe{sub 2}, CGS). The calculations are performed with consideration for the spectral distribution of AM1.5 standard solar radiation and the absorption coefficients of the materials. It is shown that, in the region of wavelengths {lambda} = {lambda}{sub g} = hc/E{sub g}, almost total absorption of the photons in AM1.5 solar radiation is attained in c-Si at the thickness d = 7-8 mm, in a-Si at d = 30-60 {mu}m, in CdTe at d = 20-30 {mu}m, and in CIS and CGS at d = 3-4 {mu}m. The results differ from previously reported data for these materials (especially for c-Si). In previous publications, the thickness needed for the semiconductor to absorb solar radiation completely was identified with the effective light penetration depth at a certain wavelength in the region of fundamental absorption for the semiconductor.

  5. The Correlation of Coupled Heat and Mass Transfer Experimental Data for Vertical Falling Film Absorption

    SciTech Connect (OSTI)

    Keyhani, M; Miller, W A

    1999-11-14

    Absorption chillers are gaining global acceptance as quality comfort cooling systems. These machines are the central chilling plants and the supply for cotnfort cooling for many large commercial buildings. Virtually all absorption chillers use lithium bromide (LiBr) and water as the absorption fluids. Water is the refrigerant. Research has shown LiBr to he one of the best absorption working fluids because it has a high affinity for water, releases water vapor at relatively low temperatures, and has a boiling point much higher than that of water. The heart of the chiller is the absorber, where a process of simultaneous heat and mass transfer occurs as the refrigerant water vapor is absorbed into a falling film of aqueous LiBr. The more water vapor absorbed into the falling film, the larger the chiller's capacity for supporting comfort cooling. Improving the performance of the absorber leads directly to efficiency gains for the chiller. The design of an absorber is very empirical and requires experimental data. Yet design data and correlations are sparse in the open literature. The experimental data available to date have been derived at LiBr concentrations ranging from 0.30 to 0.60 mass fraction. No literature data are readily available for the design operating conditions of 0.62 and 0.64 mass fraction of LiBr and absorber pressures of 0.7 and 1.0 kPa.

  6. Use of underpotential deposition of zinc to mitigate hydrogen absorption into Monel K500

    SciTech Connect (OSTI)

    Zheng, G.; Popov, B.N.; White, R.E. . Dept. of Chemical Engineering)

    1994-05-01

    Polarization experiments and a potentiostatic pulse technique have been used to show that a monolayer coverage of zinc effectively inhibits the absorption of hydrogen into Monel K500. By depositing a monolayer of zinc on Monel K500 the hydrogen, evolution reaction and hydrogen ingress flux rate were reduced by 60%.

  7. Prototype explosives-detection system based on nuclear-resonance absorption in nitrogen

    SciTech Connect (OSTI)

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1994-06-01

    A prototype explosives-detection system (EDS) that was developed for experimental evaluation of a nuclear-resonance absorption technique is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  8. Integrated three-dimensional photonic nanostructures for achieving near-unity solar absorption and superhydrophobicity

    SciTech Connect (OSTI)

    Kuang, Ping; Lin, Shawn-Yu; Hsieh, Mei-Li

    2015-06-07

    In this paper, we proposed and realized 3D photonic nanostructures consisting of ultra-thin graded index antireflective coatings (ARCs) and woodpile photonic crystals. The use of the integrated ARC and photonic crystal structure can achieve broadband, broad-angle near unity solar absorption. The amorphous silicon based photonic nanostructure experimentally shows an average absorption of ∼95% for λ = 400–620 nm over a wide angular acceptance of θ = 0°–60°. Theoretical studies show that a Gallium Arsenide (GaAs) based structure can achieve an average absorption of >95% for λ = 400–870 nm. Furthermore, the use of the slanted SiO{sub 2} nanorod ARC surface layer by glancing angle deposition exhibits Cassie-Baxter state wetting, and superhydrophobic surface is obtained with highest water contact angle θ{sub CB} ∼ 153°. These properties are fundamentally important for achieving maximum solar absorption and surface self-cleaning in thin film solar cell applications.

  9. Absorption experiments on x-ray-heated mid-{ital Z} constrained samples

    SciTech Connect (OSTI)

    Perry, T.S.; Springer, P.T.; Fields, D.F.; Bach, D.R.; Serduke, F.J.; Iglesias, C.A.; Rogers, F.J.; Nash, J.K.; Chen, M.H.; Wilson, B.G.; Goldstein, W.H.; Rozsynai, B.; Ward, R.A.; Kilkenny, J.D.; Doyas, R.; Da Silva, L.B.; Back, C.A.; Cauble, R.; Davidson, S.J.; Foster, J.M.; Smith, C.C.; Bar-Shalom, A.; Lee, R.W.

    1996-11-01

    Results of a niobium absorption experiment are presented that represent a major step in the development of techniques necessary for the quantitative characterization of hot, dense matter. The general requirements for performing quantitative analyses of absorption spectra are discussed. Hydrodynamic simulations are used to illustrate the behavior of tamped x-ray-heated matter and to indicate potential two-dimensional problems inherent in the technique. The absorption spectrum of a low-{ital Z} material, in this case aluminum, mixed with niobium provides a temperature diagnostic, which together with radiography as a density diagnostic fully characterizes the sample. A discussion is presented of opacity calculations and a comparison to the measurements is given that illustrates the need for experiments to provide a critical test of theory. The experimental technique is placed in context with a review of previous measurements using absorption spectroscopy to probe hot, dense matter. It is shown that the overall experimental concepts, although understood, were not always achieved in previous experiments. {copyright} {ital 1996 The American Physical Society.}

  10. Ab initio calculation of the electronic absorption spectrum of liquid water

    SciTech Connect (OSTI)

    Martiniano, Hugo F. M. C.; Galamba, Nuno; Cabral, Benedito J. Costa; Departamento de Qumica e Bioqumica, Faculdade de Cincias, Universidade de Lisboa, 1749-016 Lisboa; Instituto de Fsica da Universidade de So Paulo, CP 66318, 05314-970 So Paulo, SP

    2014-04-28

    The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the OH stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

  11. Data processing of absorption spectra from photoionized plasma experiments at Z

    SciTech Connect (OSTI)

    Hall, I. M.; Durmaz, T.; Mancini, R. C.; Bailey, J. E.; Rochau, G. A.

    2010-10-15

    We discuss the processing of x-ray absorption spectra from photoionized plasma experiments at Z. The data was recorded with an imaging spectrometer equipped with two elliptically bent potassium acid phthalate (KAP) crystals. Both time-integrated and time-resolved data were recorded. In both cases, the goal is to obtain the transmission spectra for quantitative analysis of plasma conditions.

  12. Enhanced Absorption in 2D Materials Via Fano- Resonant Photonic Crystals

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Wenyi; Klotz, Andrey; Yang, Yuanmu; Li, Wei; Kravchenko, Ivan I.; Briggs, Dayrl P.; Bolotin, Kirill; Valentine, Jason

    2015-05-01

    The use of two-dimensional (2D) materials in optoelectronics has attracted much attention due to their fascinating optical and electrical properties. For instance, graphenebased devices have been employed for applications such as ultrafast and broadband photodetectors and modulators while transition metal dichalcogenide (TMDC) based photodetectors can be used for ultrasensitive photodetection. However, the low optical absorption of 2D materials arising from their atomic thickness limits the maximum attainable external quantum efficiency. For example, in the visible and NIR regimes monolayer MoS2 and graphene absorb only ~10% and 2.3% of incoming light, respectively. Here, we experimentally demonstrate the use of Fano-resonant photonicmore » crystals to significantly boost absorption in atomically thin materials. Using graphene as a test bed, we demonstrate that absorption in the monolayer thick material can be enhanced to 77% within the telecommunications band, the highest value reported to date. We also show that the absorption in the Fano-resonant structure is non-local, with light propagating up to 16 μm within the structure. This property is particularly beneficial in harvesting light from large areas in field-effect-transistor based graphene photodetectors in which separation of photo-generated carriers only occurs ~0.2 μm adjacent to the graphene/electrode interface.« less

  13. Structural stability of 1100{degree}C heated Pd/k during absorption cycling in protium

    SciTech Connect (OSTI)

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110{degree}C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100{degree}C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100{degree}C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100{degree}C.

  14. Light absorption and electrical transport in Si:O alloys for photovoltaics

    SciTech Connect (OSTI)

    Mirabella, S.; Crupi, I.; Miritello, M.; Simone, F.; Di Martino, G.; Di Stefano, M. A.; Di Marco, S.; Priolo, F.

    2010-11-15

    Thin films (100-500 nm) of the Si:O alloy have been systematically characterized in the optical absorption and electrical transport behavior, by varying the Si content from 43 up to 100 at. %. Magnetron sputtering or plasma enhanced chemical vapor deposition have been used for the Si:O alloy deposition, followed by annealing up to 1250 deg. C. Boron implantation (30 keV, 3-30x10{sup 14} B/cm{sup 2}) on selected samples was performed to vary the electrical sheet resistance measured by the four-point collinear probe method. Transmittance and reflectance spectra have been extracted and combined to estimate the absorption spectra and the optical band gap, by means of the Tauc analysis. Raman spectroscopy was also employed to follow the amorphous-crystalline (a-c) transition of the Si domains contained in the Si:O films. The optical absorption and the electrical transport of Si:O films can be continuously and independently modulated by acting on different parameters. The light absorption increases (by one decade) with the Si content in the 43-100 at. % range, determining an optical band gap which can be continuously modulated into the 2.6-1.6 eV range, respectively. The a-c phase transition in Si:O films, causing a significant reduction in the absorption coefficient, occurs at increasing temperatures (from 600 to 1100 deg. C) as the Si content decreases. The electrical resistivity of Si:O films can be varied among five decades, being essentially dominated by the number of Si grains and by the doping. Si:O alloys with Si content in the 60-90 at. % range (named oxygen rich silicon films), are proved to join an appealing optical gap with a viable conductivity, being a good candidate for increasing the conversion efficiency of thin-film photovoltaic cell.

  15. Carbon dioxide postcombustion capture: a novel screening study of the carbon dioxide absorption performance of 76 amines

    SciTech Connect (OSTI)

    Graeme Puxty; Robert Rowland; Andrew Allport; Qi Yang; Mark Bown; Robert Burns; Marcel Maeder; Moetaz Attalla

    2009-08-15

    The significant and rapid reduction of greenhouse gas emissions is recognized as necessary to mitigate the potential climate effects from global warming. The postcombustion capture (PCC) and storage of carbon dioxide (CO{sub 2}) produced from the use of fossil fuels for electricity generation is a key technology needed to achieve these reductions. The most mature technology for CO{sub 2} capture is reversible chemical absorption into an aqueous amine solution. In this study the results from measurements of the CO{sub 2} absorption capacity of aqueous amine solutions for 76 different amines are presented. Measurements were made using both a novel isothermal gravimetric analysis (IGA) method and a traditional absorption apparatus. Seven amines, consisting of one primary, three secondary, and three tertiary amines, were identified as exhibiting outstanding absorption capacities. Most have a number of structural features in common including steric hindrance and hydroxyl functionality 2 or 3 carbons from the nitrogen. Initial CO{sub 2} absorption rate data from the IGA measurements was also used to indicate relative absorption rates. Most of the outstanding performers in terms of capacity also showed initial absorption rates comparable to the industry standard monoethanolamine (MEA). This indicates, in terms of both absorption capacity and kinetics, that they are promising candidates for further investigation. 30 refs., 8 figs.

  16. The role of the carbon-silicon complex in eliminating deep ultraviolet absorption in AlN

    SciTech Connect (OSTI)

    Gaddy, BE; Bryan, Z; Bryan, I; Xie, JQ; Dalmau, R; Moody, B; Kumagai, Y; Nagashima, T; Kubota, Y; Kinoshita, T; Koukitu, A; Kirste, R; Sitar, Z; Collazo, R; Irving, DL

    2014-05-19

    Co-doping AlN crystals with Si is found to suppress the unwanted 4.7 eV (265 nm) deep ultraviolet absorption associated with isolated carbon acceptors common in materials grown by physical vapor transport. Density functional theory calculations with hybrid functionals demonstrate that silicon forms a stable nearest-neighbor defect complex with carbon. This complex is predicted to absorb at 5.5 eV and emit at or above 4.3 eV. Absorption and photoluminescence measurements of co-doped samples confirm the presence of the predicted C-N-Si-Al complex absorption and emission peaks and significant reduction of the 4.7 eV absorption. Other sources of deep ultraviolet absorption in AlN are also discussed. (C) 2014 AIP Publishing LLC.

  17. Specific absorption rate calculations of magnetite, using a modified linear response model for applications in magnetic hyperthermia

    SciTech Connect (OSTI)

    Hernández S, A. E-mail: meduardo2001@hotmail.com; Cano, M. E. E-mail: meduardo2001@hotmail.com; Torres-Arenas, J.

    2014-11-07

    Currently the absorption of electromagnetic radiation by magnetic nanoparticles is studied for biomedical applications of cancer thermotherapy. Several experiments are conduced following the framework of the Rosensweig model, in order to estimate their specific absorption rate. Nevertheless, this linear approximation involves strong simplifications which constrain their accuracy and validity range. The main aim of this work is to incorporate the deviation of the sphericity assumption in particles shapes, to improve the determination of their specific absorption rate. The correction to the effective particles volume is computed as a measure of the apparent amount of magnetic material, interacting with the external AC magnetic field. Preliminary results using the physical properties of Fe3O4 nanoparticles, exhibit an important correction in their estimated specific absorption rate, as a function of the apparent mean particles radius. Indeed, we have observed using a small deviation (6% of the apparent radius), up to 40% of the predicted specific absorption rate by the Rosensweig linear approximation.

  18. Isotope Enrichment Detection by Laser Ablation - Laser Absorption Spectrometry: Automated Environmental Sampling and Laser-Based Analysis for HEU Detection

    SciTech Connect (OSTI)

    Anheier, Norman C.; Bushaw, Bruce A.

    2010-01-01

    The global expansion of nuclear power, and consequently the uranium enrichment industry, requires the development of new safeguards technology to mitigate proliferation risks. Current enrichment monitoring instruments exist that provide only yes/no detection of highly enriched uranium (HEU) production. More accurate accountancy measurements are typically restricted to gamma-ray and weight measurements taken in cylinder storage yards. Analysis of environmental and cylinder content samples have much higher effectiveness, but this approach requires onsite sampling, shipping, and time-consuming laboratory analysis and reporting. Given that large modern gaseous centrifuge enrichment plants (GCEPs) can quickly produce a significant quantity (SQ ) of HEU, these limitations in verification suggest the need for more timely detection of potential facility misuse. The Pacific Northwest National Laboratory (PNNL) is developing an unattended safeguards instrument concept, combining continuous aerosol particulate collection with uranium isotope assay, to provide timely analysis of enrichment levels within low enriched uranium facilities. This approach is based on laser vaporization of aerosol particulate samples, followed by wavelength tuned laser diode spectroscopy to characterize the uranium isotopic ratio through subtle differences in atomic absorption wavelengths. Environmental sampling (ES) media from an integrated aerosol collector is introduced into a small, reduced pressure chamber, where a focused pulsed laser vaporizes material from a 10 to 20-m diameter spot of the surface of the sampling media. The plume of ejected material begins as high-temperature plasma that yields ions and atoms, as well as molecules and molecular ions. We concentrate on the plume of atomic vapor that remains after the plasma has expanded and then cooled by the surrounding cover gas. Tunable diode lasers are directed through this plume and each isotope is detected by monitoring absorbance

  19. Priorities for In-situ Aerosol Measurements

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Priorities for In-situ Aerosol Measurements Parameters * Aerosol light absorption coefficient - spectral, including UV, vis, and IR - as f(RH), and at ambient RH * Phase function - or relevant integral properties (how many?) * Ice nuclei * Scattering vs. RH, for RH>90% * CCN, as f(S, D p ) * Size distribution * Chemical composition - for determining climate forcing, vs. radiative effect Calibration * Number concentration * Size and shape * Light absorption reference method Characterization *

  20. Reflection-Absorption Infrared Spectroscopy of Thin Films Using an External Cavity Quantum Cascade Laser

    SciTech Connect (OSTI)

    Phillips, Mark C.; Craig, Ian M.; Blake, Thomas A.

    2013-02-04

    We present experimental demonstrations using a broadly tunable external cavity quantum cascade laser (ECQCL) to perform Reflection-Absorption InfraRed Spectroscopy (RAIRS) of thin layers and residues on surfaces. The ECQCL compliance voltage was used to measure fluctuations in the ECQCL output power and improve the performance of the RAIRS measurements. Absorption spectra from self-assembled monolayers of a fluorinated alkane thiol and a thiol carboxylic acid were measured and compared with FTIR measurements. RAIRS spectra of the explosive compounds PETN, RDX, and tetryl deposited on gold substrates were also measured. Rapid measurement times and low noise were demonstrated, with < 1E-3 absorbance noise for a 10 second measurement time.

  1. Differential total absorptivity solution to the radiative transfer equation for mixtures of combustion gases and soot

    SciTech Connect (OSTI)

    Bressloff, N.W.; Moss, J.B.; Rubini, P.A.

    1997-01-01

    The differential total absorptivity (DTA) solution to the radiative transfer equation, originally devised for combustion gases in the discrete transfer radiation model, is extended to mixtures of gaseous combustion products and soot. The method is compared to other solution techniques for representative mixtures across single lines of sight and across a layer bounded by solid walls. Intermediate soot loadings are considered such that the total radiance is not dominated by either the gaseous or soot components. The DTA solution is shown to yield excellent accuracy relative to a narrow-band solution, with a considerable saving in computational cost. Thus, explicit treatment of the source temperature dependence of absorption is successfully demonstrated without the need for spectral integration.

  2. Nonlinear absorption and harmonic generation of laser in a gas with anharmonic clusters

    SciTech Connect (OSTI)

    Kumar, Manoj; Tripathi, V. K.

    2013-02-15

    The nonlinear absorption and harmonic generation of intense short pulse laser in a gas embedded with anharmonic clusters are investigated theoretically. When the laser induced excursion of cluster electrons becomes comparable to cluster radius, the restoration force on electrons no longer remains linearly proportional to the excursion. As a consequence, the plasmon resonance is broadened, leading to broadband laser absorption. It also leads to second and third harmonic generations, at much higher level than the one due to ponderomotive nonlinearity. The harmonic yield is resonantly enhanced at the plasmon resonance {omega}={omega}{sub pe}/{radical}(3), where {omega} is the frequency of the laser and {omega}{sub pe} is the plasma frequency of cluster electrons.

  3. X-ray absorption spectroscopic studies of mononuclear non-heme iron enzymes

    SciTech Connect (OSTI)

    Westre, T.E.

    1996-01-01

    Fe-K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the electronic and geometric structure of the iron active site in non-heme iron enzymes. A new theoretical extended X-ray absorption fine structure (EXAFS) analysis approach, called GNXAS, has been tested on data for iron model complexes to evaluate the utility and reliability of this new technique, especially with respect to the effects of multiple-scattering. In addition, a detailed analysis of the 1s{yields}3d pre-edge feature has been developed as a tool for investigating the oxidation state, spin state, and geometry of iron sites. Edge and EXAFS analyses have then been applied to the study of non-heme iron enzyme active sites.

  4. Cascading metallic gratings for broadband absorption enhancement in ultrathin plasmonic solar cells

    SciTech Connect (OSTI)

    Wen, Long; Sun, Fuhe; Chen, Qin

    2014-04-14

    The incorporation of plasmonic nanostructures in the thin-film solar cells (TFSCs) is a promising route to harvest light into the nanoscale active layer. However, the light trapping scheme based on the plasmonic effects intrinsically presents narrow-band resonant enhancement of light absorption. Here we demonstrate that by cascading metal nanogratings with different sizes atop the TFSCs, broadband absorption enhancement can be realized by simultaneously exciting multiple localized surface plasmon resonances and inducing strong coupling between the plasmonic modes and photonic modes. As a proof of concept, we demonstrate of 66.5% in the photocurrent in an ultrathin amorphous silicon TFSC with two-dimensional cascaded gratings over the reference cell without gratings.

  5. Theory of triplet optical absorption in oligoacenes: From naphthalene to heptacene

    SciTech Connect (OSTI)

    Chakraborty, Himanshu Shukla, Alok

    2014-10-28

    In this paper, we present a detailed theory of the triplet states of oligoacenes containing up to seven rings, i.e., starting from naphthalene all the way up to heptacene. In particular, we present results on the optical absorption from the first triplet excited state 1{sup 3}B{sub 2u}{sup +} of these oligomers, computed using the Pariser-Parr-Pople model Hamiltonian, and a correlated electron approach employing the configuration-interaction methodology at various levels. Excitation energies of various triplets states obtained by our calculations are in good agreement with the experimental results, where available. The computed triplet spectra of oligoacenes exhibits rich structure dominated by two absorption peaks of high intensities, which are well separated in energy, and are caused by photons polarized along the conjugation direction. This prediction of ours can be tested in future experiments performed on oriented samples of oligoacenes.

  6. An improved absorption generator for solar-thermal powered heat pumps. Part 1: Feasibility

    SciTech Connect (OSTI)

    Fineblum, S.

    1997-12-31

    Solar heated absorption chiller installations have been, typically, very expensive for their rating. The need to keep the liquid flowing within the collectors as cool as possible to enhance collector thermal efficiency, conflicts with the need to operate the absorption chiller at a higher temperature. The compromise usually results in poor collector efficiency as well as a relatively poor specific chiller effect. The proposed vortex generator permits a heat pump to operate efficiently with relatively low temperature solar heated fluid (70--80 C). As a result, the collectors are cooler and much more efficient. In addition, the specific heat pumping capacity is about 27% greater than conventional systems operating at the same reduced generator temperatures and, therefore, a smaller chiller is required. The economic consequences of these benefits will be presented in Part 2.

  7. Regeneration of an aqueous solution from an acid gas absorption process by matrix stripping

    DOE Patents [OSTI]

    Rochelle, Gary T.; Oyenekan, Babatunde A.

    2011-03-08

    Carbon dioxide and other acid gases are removed from gaseous streams using aqueous absorption and stripping processes. By replacing the conventional stripper used to regenerate the aqueous solvent and capture the acid gas with a matrix stripping configuration, less energy is consumed. The matrix stripping configuration uses two or more reboiled strippers at different pressures. The rich feed from the absorption equipment is split among the strippers, and partially regenerated solvent from the highest pressure stripper flows to the middle of sequentially lower pressure strippers in a "matrix" pattern. By selecting certain parameters of the matrix stripping configuration such that the total energy required by the strippers to achieve a desired percentage of acid gas removal from the gaseous stream is minimized, further energy savings can be realized.

  8. Imaging electronic trap states in perovskite thin films with combined fluorescence and femtosecond transient absorption microscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xiao, Kai; Ma, Ying -Zhong; Simpson, Mary Jane; Doughty, Benjamin; Yang, Bin

    2016-04-22

    Charge carrier trapping degrades the performance of organometallic halide perovskite solar cells. To characterize the locations of electronic trap states in a heterogeneous photoactive layer, a spatially resolved approach is essential. Here, we report a comparative study on methylammonium lead tri-iodide perovskite thin films subject to different thermal annealing times using a combined photoluminescence (PL) and femtosecond transient absorption microscopy (TAM) approach to spatially map trap states. This approach coregisters the initially populated electronic excited states with the regions that recombine radiatively. Although the TAM images are relatively homogeneous for both samples, the corresponding PL images are highly structured. Themore » remarkable variation in the PL intensities as compared to transient absorption signal amplitude suggests spatially dependent PL quantum efficiency, indicative of trapping events. Furthermore, detailed analysis enables identification of two trapping regimes: a densely packed trapping region and a sparse trapping area that appear as unique spatial features in scaled PL maps.« less

  9. Process for removal of carbonyl sulfide in liquified hydrocarbon gases with absorption of acid gases

    SciTech Connect (OSTI)

    Beavon, D.K.; Mackles, M.

    1980-11-11

    Liquified hydrocarbon gases containing at least carbonyl sulfide as an impurity are purified by intimately mixing the liquified hydrocarbon gas with an aqueous absorbent for hydrogen sulfide in a hydrolysis zone maintained at a temperature and a pressure sufficient to maintain the liquified hydrocarbon gas in the liquid state and hydrolyze the carbonyl sulfide to hydrogen sulfide and carbon dioxide. The liquified hydrocarbon gas containing at least a portion of the formed carbonyl sulfide and carbon dioxide is separated from the liquid absorbent and passed to an absorption zone where it is contacted with a liquid hydrogen sulfide absorbent where at least the formed hydrogen sulfide is separated from the liquified petroleum gas. A stage of absorption of at least hydrogen sulfide may proceed mixing of the liquified hydrocarbon gas with the absorbent in the hydrolysis reaction zone. The absorbent employed does not combine irreversibly with carbonyl sulfide, hydrogen sulfide, and carbon dioxide, and preferably is an aqueous solution of diethanolamine.

  10. Moisture absorption and bakeout characteristics of rigid-flexible multilayer printed wiring boards

    SciTech Connect (OSTI)

    Lula, J.W.

    1991-01-01

    Moisture absorption and bakeout characteristics of Allied-Signal Inc., Kansas City Division (KCD) rigid-flexible printed wiring boards were determined. It was found that test specimens had absorbed 0.95 weight percent moisture when equilibrated to a 50 percent RH, 25{degree}C environment. Heating those equilibrated specimens in a 120{degree}C static air oven removed 92 percent of this absorbed moisture in 24 h. Heating the samples in a 80{degree}C static air oven removed only 64 percent of the absorbed moisture at the end of 24 h. A 120{degree}C vacuum bake removed moisture at essentially the same rate with parylene slowed the absorption rate by approximately 50 percent but did not appreciably affect the equilibrium moisture content or the drying rate.

  11. New constraints in absorptive capacity and the optimum rate of petroleum output

    SciTech Connect (OSTI)

    El Mallakh, R

    1980-01-01

    Economic policy in four oil-producing countries is analyzed within a framework that combines a qualitative assessment of the policy-making process with an empirical formulation based on historical and current trends in these countries. The concept of absorptive capacity is used to analyze the optimum rates of petroleum production in Iran, Iraq, Saudi Arabia, and Kuwait. A control solution with an econometric model is developed which is then modified for alternative development strategies based on analysis of factors influencing production decisions. The study shows the consistencies and inconsistencies between the goals of economic growth, oil production, and exports, and the constraints on economic development. Simulation experiments incorporated a number of the constraints on absorptive capacity. Impact of other constraints such as income distribution and political stability is considered qualitatively. (DLC)

  12. Differential absorption lidar measurements of atmospheric temperature profiles - Theory and experiment

    SciTech Connect (OSTI)

    Theopold, F.A.; Boesenberg, J. )

    1993-04-01

    The method of measuring atmospheric temperature profiles with differential absorption lidar (DIAL), based on the temperature dependence of oxygen absorption lines in the near-IR, is investigated in detail. Particularly, the influence of Doppler broadening on the Rayleigh-backscattered signal is evaluated, and a correction method for this effect is presented which requires an accurate estimate of the molecular and particle backscatter contributions; this is noted not to be achievable by the usual lidar inversion techniques. Under realistic conditions, resulting errors may be as high as 10 K. First range-resolved measurements using this technique are presented, using a slightly modified DIAL system originally constructed for water vapor measurements. While much better resolution can certainly be achieved by technical improvements, the errors introduced by the uncertainty of the backscatter contributions will remain and determine the accuracy that can be obtained with this method. 35 refs.

  13. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectropscopy using IFEFFIT

    SciTech Connect (OSTI)

    Ravel, B.; Newville, M.

    2010-07-20

    A software package for the analysis of X-ray absorption spectroscopy (XAS) data is presented. This package is based on the IFEFFIT library of numerical and XAS algorithms and is written in the Perl programming language using the Perl/Tk graphics toolkit. The programs described here are: (i) ATHENA, a program for XAS data processing, (ii) ARTEMIS, a program for EXAFS data analysis using theoretical standards from FEFF and (iii) HEPHAESTUS, a collection of beamline utilities based on tables of atomic absorption data. These programs enable high-quality data analysis that is accessible to novices while still powerful enough to meet the demands of an expert practitioner. The programs run on all major computer platforms and are freely available under the terms of a free software license.

  14. Energetic Aspects of CO2 Absorption by Ionic Liquids from Quantum Monte

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Carlo | Argonne Leadership Computing Facility The main image shows a projection of the energetic landscape of a CO2 molecule (oriented along the X-axis) from a high-dimensional space of QMC random walks into the real space. Inset: a matching two-dimensional slice containing the linear CO2 molecule; blue colors correspond to the nuclear regions where electrons experience strong attractive potential. William Lester, Jr. Energetic Aspects of CO2 Absorption by Ionic Liquids from Quantum Monte

  15. Atomic structure of machined semiconducting chips: An x-ray absorption spectroscopy study

    SciTech Connect (OSTI)

    Paesler, M.; Sayers, D.

    1988-12-01

    X-ray absorption spectroscopy (XAS) has been used to examine the atomic structure of chips of germanium that were produced by single point diamond machining. It is demonstrated that although the local (nearest neighbor) atomic structure is experimentally quite similar to that of single crystal specimens information from more distant atoms indicates the presence of considerable stress. An outline of the technique is given and the strength of XAS in studying the machining process is demonstrated.

  16. Nonequilibrium Green's function formulation of intersubband absorption for nonparabolic single-band effective mass Hamiltonian

    SciTech Connect (OSTI)

    Kolek, Andrzej

    2015-05-04

    The formulas are derived that enable calculations of intersubband absorption coefficient within nonequilibrium Green's function method applied to a single-band effective-mass Hamiltonian with the energy dependent effective mass. The derivation provides also the formulas for the virtual valence band components of the two-band Green's functions which can be used for more exact estimation of the density of states and electrons and more reliable treatment of electronic transport in unipolar n-type heterostructure semiconductor devices.

  17. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also presentmore » data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.« less

  18. Charge-transfer absorption and emission in polymer: fullerene solar cells |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    MIT-Harvard Center for Excitonics Charge-transfer absorption and emission in polymer: fullerene solar cells April 13, 2010 at 3pm/36-428 Koen Vandewal Linköping University vandewal-small abstract: For an efficient conversion of photons to electrons by organic materials, the presence of a material interface between an electron donating and electron accepting material is crucial. Most successful active layers for organic solar cells today comprise a blend of conjugated polymers as electron

  19. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

  20. Structural color printing based on plasmonic metasurfaces of perfect light absorption

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong

    2015-06-05

    Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfectmore » light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.« less

  1. Structural color printing based on plasmonic metasurfaces of perfect light absorption

    SciTech Connect (OSTI)

    Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong

    2015-06-05

    Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.

  2. UV absorption spectrum of the C2 Criegee intermediate CH{sub 3}CHOO

    SciTech Connect (OSTI)

    Smith, Mica C.; Ting, Wei-Lun; Chang, Chun-Hung; Takahashi, Kaito; Boering, Kristie A.; Lin, Jim Jr-Min

    2014-08-21

    The UV spectrum of CH{sub 3}CHOO was measured by transient absorption in a flow cell at 295 K. The absolute absorption cross sections of CH{sub 3}CHOO were measured by laser depletion in a molecular beam to be (1.06 ± 0.09) × 10{sup −17} cm{sup 2} molecule{sup −1} at 308 nm and (9.7 ± 0.6) × 10{sup −18} cm{sup 2} molecule{sup −1} at 352 nm. After scaling the UV spectrum of CH{sub 3}CHOO to the absolute cross section at 308 nm, the peak UV cross section is (1.27 ± 0.11) × 10{sup −17} cm{sup 2} molecule{sup −1} at 328 nm. Compared to the simplest Criegee intermediate CH{sub 2}OO, the UV absorption band of CH{sub 3}CHOO is similar in intensity but blue shifted by 14 nm, resulting in a 20% slower photolysis rate estimated for CH{sub 3}CHOO in the atmosphere.

  3. Absorption and scattering of laser radiation by the diffusion flame of aviation kerosene

    SciTech Connect (OSTI)

    Gvozdev, S V; Glova, A F; Dubrovskii, V Yu; Durmanov, S T; Krasyukov, A G; Lysikov, A Yu; Smirnov, G V; Solomakhin, V B

    2012-04-30

    The absorption coefficient of the radiation of a repetitively pulsed Nd : YAG laser with an average output power up to 6 W and of a cw ytterbium optical fibre laser with an output power up to 3 kW was measured in the diffusion flame of aviation kerosene burning on a free surface in the atmospheric air. The absorption coefficient as a function of flame length, radiation power, and radiation intensity, which was varied in the {approx}10{sup 3} - 5 Multiplication-Sign 10{sup 4} W cm{sup -2} range, was obtained for two distances (1 and 2 cm) between the laser beam axis and the surface. The coefficient of radiation absorption by kerosene flame was compared with that in ethanol and kerosene - ethanol mixture flames. The radiation power scattered by a small segment of the kerosene flame irradiated by Nd : YAG laser radiation was measured as a function of longitudinal and azimuthal coordinates. An estimate was made of the total scattered radiation power.

  4. Femtosecond x-ray absorption spectroscopy with hard x-ray free electron laser

    SciTech Connect (OSTI)

    Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Kameshima, Takashi; Inubushi, Yuichi; Sato, Takahiro; Hatsui, Takaki; Yabashi, Makina; Obara, Yuki; Misawa, Kazuhiko; Bhattacharya, Atanu; Kurahashi, Naoya; Ogi, Yoshihiro; Suzuki, Toshinori; Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198

    2013-09-23

    We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (ΔE/E ∼ 5 × 10{sup −3}), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ∼3 × 10{sup −3}, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.

  5. Optimization of a solar powered absorption cycle under Abu Dhabi's weather conditions

    SciTech Connect (OSTI)

    Al-Alili, A.; Hwang, Y.; Radermacher, R.; Kubo, I.

    2010-12-15

    In order for the solar absorption air conditioners to become a real alternative to the conventional vapour compression systems, their performance has to be improved and their total cost has to be reduced. A solar powered absorption cycle is modeled using the Transient System Simulation (TRNSYS) program and Typical Meteorological Year 2 data of Abu Dhabi. It uses evacuated tube collectors to drive a 10 kW ammonia-water absorption chiller. Firstly, the system performance and its total cost are optimized separately using single objective optimization algorithms. The design variables considered are: the collector slope, the collector mass flow rate, the collector area and the storage tank volume. The single objective optimization results show that MATLAB global optimization methods agree with the TRNSYS optimizer. Secondly, MATLAB is used to solve a multi-objective optimization problem to improve the system's performance and cost, simultaneously. The optimum designs are presented using Pareto curve and show the potential improvements of the baseline system. (author)

  6. GAS AND DUST ABSORPTION IN THE DoAr 24E SYSTEM

    SciTech Connect (OSTI)

    Kruger, Andrew J.; Richter, Matthew J.; Seifahrt, Andreas; Carr, John S.; Najita, Joan R.; Moerchen, Margaret M.; Doppmann, Greg W.

    2012-11-20

    We present findings for DoAr 24E, a binary system that includes a classical infrared companion. We observed the DoAr 24E system with the Spitzer Infrared Spectrograph (IRS), with high-resolution, near-infrared spectroscopy of CO vibrational transitions, and with mid-infrared imaging. The source of high extinction toward infrared companions has been an item of continuing interest. Here we investigate the disk structure of DoAr 24E using the column densities, temperature, and velocity profiles of two CO absorption features seen toward DoAr 24Eb. We model the spectral energy distributions found using T-ReCS imaging and investigate the likely sources of extinction toward DoAr 24Eb. We find the lack of silicate absorption and small CO column density toward DoAr 24Eb suggest that the mid-infrared continuum is not as extinguished as the near-infrared, possibly due to the mid-infrared originating from an extended region. This, along with the velocity profile of the CO absorption, suggests that the source of high extinction is likely due to a disk or disk wind associated with DoAr 24Eb.

  7. Method and apparatus for measuring butterfat and protein content using microwave absorption techniques

    DOE Patents [OSTI]

    Fryer, Michael O.; Hills, Andrea J.; Morrison, John L.

    2000-01-01

    A self calibrating method and apparatus for measuring butterfat and protein content based on measuring the microwave absorption of a sample of milk at several microwave frequencies. A microwave energy source injects microwave energy into the resonant cavity for absorption and reflection by the sample undergoing evaluation. A sample tube is centrally located in the resonant cavity passing therethrough and exposing the sample to the microwave energy. A portion of the energy is absorbed by the sample while another portion of the microwave energy is reflected back to an evaluation device such as a network analyzer. The frequency at which the reflected radiation is at a minimum within the cavity is combined with the scatter coefficient S.sub.11 as well as a phase change to calculate the butterfat content in the sample. The protein located within the sample may also be calculated in a likewise manner using the frequency, S.sub.11 and phase variables. A differential technique using a second resonant cavity containing a reference standard as a sample will normalize the measurements from the unknown sample and thus be self-calibrating. A shuttered mechanism will switch the microwave excitation between the unknown and the reference cavities. An integrated apparatus for measuring the butterfat content in milk using microwave absorption techniques is also presented.

  8. Solidification of Acidic, High Nitrate Nuclear Wastes by Grouting or Absorption on Silica Gel

    SciTech Connect (OSTI)

    A. K. Herbst; S. V. Raman; R. J. Kirkham

    2004-01-01

    The use of grout and silica gel were explored for the solidification of four types of acidic, high nitrate radioactive wastes. Two methods of grouting were tested: direct grouting and pre-neutralization. Two methods of absorption on silica gel were also tested: direct absorption and rotary spray drying. The waste simulant acidity varied between 1 N and 12 N. The waste simulant was neutralized by pre-blending calcium hydroxide with Portland cement and blast furnace slag powders prior to mixing with the simulant for grout solidification. Liquid sodium hydroxide was used to partially neutralize the simulant to a pH above 2 and then it was absorbed for silica gel solidification. Formulations for each of these methods are presented along with waste form characteristics and properties. Compositional variation maps for grout formulations are presented which help determine the optimum "recipe" for a particular waste stream. These maps provide a method to determine the proportions of waste, calcium hydroxide, Portland cement, and blast furnace slag that provide a waste form that meets the disposal acceptance criteria. The maps guide researchers in selecting areas to study and provide an operational envelop that produces acceptable waste forms. The grouts both solidify and stabilize the wastes, while absorption on silica gel produces a solid waste that will not pass standard leaching procedures (TCLP) if required. Silica gel wastes can be made to pass most leach tests if heated to 600C.

  9. Ultrafast recovery time and broadband saturable absorption properties of black phosphorus suspension

    SciTech Connect (OSTI)

    Wang, Yingwei; Huang, Guanghui; Chen, Jiazhang; Xiao, Si He, Jun; Mu, Haoran; Bao, Qiaoliang; Lin, Shenghuang

    2015-08-31

    As a new type of two-dimensional crystal material, black phosphorus (BP) exhibits excellent electronics and optical performance. Herein, we focus on carrier relaxation dynamics and nonlinear optical properties of BP suspension. Atomic force microscopy, transmission electron microscopy, and optical transmission spectrum are employed to characterize the structure and linear optical properties of the BP. Additionally, pump-probe experiments at wavelength of 1550 nm were carried out to study the carrier dynamics in BP suspension, and ultrafast recovery time was observed (τ{sub s} = 24 ± 2 fs). Furthermore, we demonstrate the saturable absorption signals by open aperture Z-scan experiments at wavelengths of 1550 nm, 532 nm, and 680 nm. The results indicate that BP has broadband saturable absorption properties and the nonlinear absorption coefficients were determined to be β{sub 2} = −0.20 ± 0.08 × 10{sup −3 }cm/GW (532 nm), β{sub 2} = −0.12 ± 0.05 × 10{sup −3 }cm/GW (680 nm), and β{sub 2} = −0.15 ± 0.09 × 10{sup −3 }cm/GW (1550 nm)

  10. THE EFFECT OF 3HE ON LOW PRESSURE HYDRIDE ABSORPTION MEASUREMENTS WITH TRITIUM

    SciTech Connect (OSTI)

    Staack, G.; Klein, J.

    2011-01-20

    Absorption isotherm data exists for a wide variety of hydrogen-metal systems. When working with high purity gases, appropriately sized equipment, and hydrides with equilibrium pressures above several hundred Pa, data collection is relatively straightforward. Special consideration must be given to experiments involving low equilibrium pressure hydrides, as even sub-ppm levels of gas impurities can generate partial pressures many times greater than the equilibrium pressures to be measured. Tritium absorption experiments are further complicated by the continuous generation of helium-3. The time required to transfer and absorb a known quantity of tritium onto a sample ultimately limits the minimum pressure range that can be studied using the standard technique. Equations are presented which show the pressure of helium-3 in a sample cell based on the amount of tritium to be absorbed, the sample cell volume and temperature, and the decay time of tritium. Sample calculations for zirconium show that at 300 C, the estimated helium-3 pressure in the cell will be equal to the hydrogen absorption pressure after only milliseconds of tritium decay. An alternate method is presented that permits the collection of equilibrium data at pressures orders of magnitude lower than possible using a direct approach.

  11. Particle size effect of hydride formation and surface hydrogen absorption of nanosized palladium catalysts : L{sub 3} edge vs K edge x-ray absorption spectroscopy.

    SciTech Connect (OSTI)

    Tew, M. W.; Miller, J. T.; van Bokhoven, J. A.

    2009-08-01

    The particle size effect on the formation of palladium hydride and on surface hydrogen adsorption was studied at room temperature using in situ X-ray absorption spectroscopy at the Pd K and L{sub 3} edges. Hydride formation was indirectly observed by lattice expansion in Pd K edge XANES spectra and by EXAFS analysis. Hydride formation was directly detected in the L{sub 3} edge spectra. A characteristic spectral feature caused by the formation of a Pd-H antibonding state showed strong particle size dependence. The L{sub 3} edge spectra were reproduced using full multiple scattering analysis and density of state calculations, and the contributions of bulk absorbed and surface hydrogen to the XANES spectra could be distinguished. The ratio of hydrogen on the surface versus that in the bulk increased with decreasing particle size, and smaller particles dissolved less hydrogen.

  12. A Novel Absorption Cycle for Combined Water Heating, Dehumidification, and Evaporative Cooling

    SciTech Connect (OSTI)

    CHUGH, Devesh; Gluesenkamp, Kyle R; Abdelaziz, Omar; Moghaddam, Saeed

    2014-01-01

    In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser. The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the

  13. CO AND H{sub 2} ABSORPTION IN THE AA TAURI CIRCUMSTELLAR DISK

    SciTech Connect (OSTI)

    France, Kevin; Burgh, Eric B.; Schindhelm, Eric; Brown, Alexander; Herczeg, Gregory J.; Yang, Hao; Linsky, Jeffrey L.; Abgrall, Herve; Roueff, Evelyne; Brown, Joanna M.

    2012-01-01

    The direct study of molecular gas in inner protoplanetary disks is complicated by uncertainties in the spatial distribution of the gas, the time variability of the source, and the comparison of observations across a wide range of wavelengths. Some of these challenges can be mitigated with far-ultraviolet spectroscopy. Using new observations obtained with the Hubble Space Telescope Cosmic Origins Spectrograph, we measure column densities and rovibrational temperatures for CO and H{sub 2} observed on the line of sight through the AA Tauri circumstellar disk. CO A - X absorption bands are observed against the far-UV continuum. The CO absorption is characterized by log{sub 10}(N({sup 12}CO)) = 17.5 {+-} 0.5 cm{sup -2} and T{sub rot}(CO) = 500{sup +500}{sub -200} K, although this rotational temperature may underestimate the local kinetic temperature of the CO-bearing gas. We also detect {sup 13}CO in absorption with an isotopic ratio of {approx}20. We do not observe H{sub 2} absorption against the continuum; however, hot H{sub 2} (v > 0) is detected in absorption against the Ly{alpha} emission line. We measure the column densities in eight individual rovibrational states, determining a total log{sub 10}(N(H{sub 2})) = 17.9{sup +0.6}{sub -0.3} cm{sup -2} with a thermal temperature of T(H{sub 2}) = 2500{sup +800}{sub -700} K. The high temperature of the molecules, the relatively small H{sub 2} column density, and the high inclination of the AA Tauri disk suggest that the absorbing gas resides in an inner disk atmosphere. If the H{sub 2} and CO are cospatial within a molecular layer {approx}0.6 AU thick, this region is characterized by {approx} 10{sup 5} cm{sup -3} with an observed (CO/H{sub 2}) ratio of {approx}0.4. We also find evidence for a departure from a purely thermal H{sub 2} distribution, suggesting that excitation by continuum photons and H{sub 2} formation may be altering the level populations in the molecular gas.

  14. Temperature dependence of the Pd [ital K]-edge extended x-ray-absorption fine structure of PdC[sub [ital x

    SciTech Connect (OSTI)

    McCaulley, J.A. (Hoechst Celanese Research Division, Robert L. Mitchell Technical Center, 86 Morris Avenue, Summit, New Jersey 07901 (United States))

    1993-03-01

    Pd [ital K]-edge extended x-ray-absorption fine-structure (EXAFS) and x-ray-absorption near-edge-structure (XANES) measurements were performed on a Pd carbide phase, PdC[sub [ital x

  15. Alternation of the Pd Lattice in Nano-Sized-Pd/ZrO2 Composite during Hydrogen Absorption

    SciTech Connect (OSTI)

    Arachi, Yoshinori; Asai, Takeshi; Emura, Shuichi; Omura, Akira; Nunogaki, Masanobu; Yamaura, Shunichi; Inoue, Akihisa; Arata, Yoshiaki

    2007-02-02

    Structural analysis of high Deuterium absorbed 5 nm Pd particles in dispersed ZrO2 has been carried out using XAFS techniques. X-ray absorption spectra around the Pd K-absorption edge were observed and analyzed. The Pd-Pd bonding distance in the fcc Pd lattice was enlarged by 0.08 {approx} 0.09 A during absorption of deuterium, and it completely reverted to its original state with the release of deuterium while maintaining the crystal lattice symmetry. These changes provide evidence that deuterium locates not on the surface of the Pd particle, but rather within the Pd crystal lattice. XANES spectra clearly indicate that any change in the oxidation state of Pd are not observed, resulting in no reaction of the absorbed Deuterium atoms with Pd atoms. This paper reports the alternation of Pd lattice in nano-sized composite during hydrogen absorption. The possible models of deuterium position in the Pd lattice are also discussed.

  16. Measurement and modeling of infrared nonlinear absorption coefficients and laser-induced damage thresholds in Ge and GaSb

    SciTech Connect (OSTI)

    Wagner, T. J.; Bohn, M. J.; Coutu, R. A. Jr.; Gonzalez, L. P.; Murray, J. M.; Guha, S.; Schepler, K. L.

    2010-10-15

    Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 {mu}m for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 {mu}m and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al{sub 2}O{sub 3} anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond pulses, respectively.

  17. Quantitative broadband absorption and scattering spectroscopy in turbid media by combined frequency-domain and steady state methodologies

    DOE Patents [OSTI]

    Tromberg, Bruce J.; Berger, Andrew J.; Cerussi, Albert E.; Bevilacqua, Frederic; Jakubowski, Dorota

    2008-09-23

    A technique for measuring broadband near-infrared absorption spectra of turbid media that uses a combination of frequency-domain and steady-state reflectance methods. Most of the wavelength coverage is provided by a white-light steady-state measurement, whereas the frequency-domain data are acquired at a few selected wavelengths. Coefficients of absorption and reduced scattering derived from the frequency-domain data are used to calibrate the intensity of the steady-state measurements and to determine the reduced scattering coefficient at all wavelengths in the spectral window of interest. The absorption coefficient spectrum is determined by comparing the steady-state reflectance values with the predictions of diffusion theory, wavelength by wavelength. Absorption spectra of a turbid phantom and of human breast tissue in vivo, derived with the combined frequency-domain and steady-state technique, agree well with expected reference values.

  18. Simulation of energy absorption spectrum in NaI crystal detector for multiple gamma energy using Monte Carlo method

    SciTech Connect (OSTI)

    Wirawan, Rahadi; Waris, Abdul; Djamal, Mitra; Handayani, Gunawan

    2015-04-16

    The spectrum of gamma energy absorption in the NaI crystal (scintillation detector) is the interaction result of gamma photon with NaI crystal, and it’s associated with the photon gamma energy incoming to the detector. Through a simulation approach, we can perform an early observation of gamma energy absorption spectrum in a scintillator crystal detector (NaI) before the experiment conducted. In this paper, we present a simulation model result of gamma energy absorption spectrum for energy 100-700 keV (i.e. 297 keV, 400 keV and 662 keV). This simulation developed based on the concept of photon beam point source distribution and photon cross section interaction with the Monte Carlo method. Our computational code has been successfully predicting the multiple energy peaks absorption spectrum, which derived from multiple photon energy sources.

  19. Determination of microgram amounts of selenium and tellurium in copper-base alloys by atomic absorption spectrometry

    SciTech Connect (OSTI)

    Bedrossian, M.

    1984-02-01

    Trace amounts of selenium and tellurium in copper-base alloys are determined by atomic absorption spectroscopy. The alloys are dissolved in nitric acid to yield selenious and tellurous acids which are readily reduced to elemental form. Iodide complexes of both selenium and tellurium are extracted simultaneously using a solution of trioctylphosphine oxide and methyl isobutyl ketone. Selenium and tellurium are determined by flame atomic absorption with a sensitivity of 0.0002%. 6 references, 2 tables.

  20. H I 21 cm ABSORPTION AND UNIFIED SCHEMES OF ACTIVE GALACTIC NUCLEI

    SciTech Connect (OSTI)

    Curran, S. J.; Whiting, M. T.

    2010-03-20

    In a recent study of z >= 0.1 active galactic nuclei (AGNs), we found that 21 cm absorption has never been detected in objects in which the ultraviolet luminosity exceeds L{sub UV} {approx} 10{sup 23} W Hz{sup -1}. In this paper, we further explore the implications that this has for the currently popular consensus that it is the orientation of the circumnuclear obscuring torus, invoked by unified schemes of AGNs, which determines whether absorption is present along our sight line. The fact that at L{sub UV} {approx}< 10{sup 23} W Hz{sup -1}, both type-1 and type-2 objects exhibit a 50% probability of detection, suggests that this is not the case and that the bias against detection of H I absorption in type-1 objects is due purely to the inclusion of the L{sub UV} {approx}> 10{sup 23} W Hz{sup -1} sources. Similarly, the ultraviolet luminosities can also explain why the presence of 21 cm absorption shows a preference for radio galaxies over quasars and the higher detection rate in compact sources, such as compact steep spectrum or gigahertz peaked spectrum sources, may also be biased by the inclusion of high-luminosity sources. Being comprised of all 21 cm searched sources at z >= 0.1, this is a necessarily heterogeneous sample, the constituents of which have been observed by various instruments. By this same token, however, the dependence on the UV luminosity may be an all encompassing effect, superseding the unified schemes model, although there is the possibility that the exclusive 21 cm non-detections at high UV luminosities could be caused by a bias toward gas-poor ellipticals. Additionally, the high UV fluxes could be sufficiently exciting/ionizing the H I above 21 cm detection thresholds, although the extent to which this is related to the neutral gas deficit in ellipticals is currently unclear. Examining the moderate UV luminosity (L{sub UV} {approx}< 10{sup 23} W Hz{sup -1}) sample further, from the profile widths and offsets from the systemic velocities

  1. Development and Evaluation of a Novel Integrated Vacuum Carbonate Absorption Process

    SciTech Connect (OSTI)

    Lu, Yongqi; Rostam-Abadi, Massoud; Ye, Xinhuai; Zhang, Shihan; Ruhter, David; Khodayari, Arezoo; Rood, Mark

    2012-04-30

    This project was aimed at obtaining process engineering and scale-up data at a laboratory scale to investigate the technical and economic feasibility of a patented post-combustion carbon dioxide (CO{sub 2}) capture process?the Integrated Vacuum Carbonate Absorption Process (IVCAP). Unique features of the IVCAP include its ability to be fully-integrated with the power plant?s steam cycle and potential for combined sulfur dioxide (SO{sub 2}) removal and CO{sub 2} capture. Theoretical and experimental studies of this project were aimed at answering three major technical questions: 1) What additives can effectively reduce the water vapor saturation pressure and energy requirement for water vaporization in the vacuum stripper of the IVCAP? 2) What catalysts can promote CO{sub 2} absorption into the potassium carbonate (PC) solution to achieve an overall absorption rate comparable to monoethanolamine (MEA) and are the catalysts stable at the IVCAP conditions and in the flue gas environment? 3) Are any process modifications needed to combine SO{sub 2} and CO{sub 2} removal in the IVCAP? Lab-scale experiments and thermodynamic and process simulation studies performed to obtain detailed information pertinent to the above three technical questions produced the following results: 1) Two additives were identified that lower the saturation pressure of water vapor over the PC solution by about 20%. 2) The carbonic anhydrase (CA) enzyme was identified as the most effective catalyst for promoting CO{sub 2} absorption. The absorption rate into the CO{sub 2}-lean PC solution promoted with 300 mg/L CA was several times slower than the corresponding 5 M MEA solution, but absorption into the CO{sub 2}-rich PC solution was comparable to the CO{sub 2}-rich MEA solution. The tested CA enzymes demonstrated excellent resistance to major flue gas impurities. A technical-grade CA enzyme was stable at 40{degrees}C (104{degrees}F) over a six-month test period, while its half-life was about two

  2. Facilely preparation and microwave absorption properties of Fe{sub 3}O{sub 4} nanoparticles

    SciTech Connect (OSTI)

    Wang, Guiqin, E-mail: wanggq@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Chang, Yongfeng; Wang, Lifang; Liu, Lidong; Liu, Chao [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China)

    2013-03-15

    Highlights: ? A bran-new method is firstly used to fabricate Fe{sub 3}O{sub 4} nanoparticles. ? The detailed analysis of formation mechanism is discussed. ? The electromagnetic absorption properties are defined. ? The effect of nanometer-sized is considered for the excellent microwave absorption. - Abstract: The Fe{sub 3}O{sub 4} nanoparticles were prepared by a novel wet-chemical method which shows its highly synthesizing efficiency and controllability. A possible formation mechanism was also proposed to explain the synthesizing process. X-ray diffraction (XRD) and transmission electron microscope (TEM) were employed and yielded an examination of an average diameter of 77 nm of the as-synthesized Fe{sub 3}O{sub 4} nanoparticles with face-centered cubic structure. Vibrating sample magnetometer (VSM) and vector network analyzer were employed to measure the magnetic property and electromagnetic parameters of the nanoparticles, then reflection losses (RL (dB)) were calculated in the frequency range of 218 GHz. A large saturation magnetization (72.36 emu/g) and high coercivity (95 Oe) were determined and indicated that the Fe{sub 3}O{sub 4} nanoparticles own strong magnetic performance. Following simulation results showed that the lowest reflection loss of the sample was ?21.2 dB at 5.6 GHz with layer thickness of 6 mm. Effect of nanometer-sized further provided an explanation for the excellent microwave absorption behavior shown by the Fe{sub 3}O{sub 4} nanoparticles.

  3. Novel insight into the hydrogen absorption mechanism at the Pd(110) surface

    SciTech Connect (OSTI)

    Ohno, Satoshi E-mail: wilde@iis.u-tokyo.ac.jp; Wilde, Markus E-mail: wilde@iis.u-tokyo.ac.jp; Fukutani, Katsuyuki

    2014-04-07

    The microscopic mechanism of low-temperature (80 K < T < 160 K) hydrogen (H) ingress into the H{sub 2} (<2.66 10{sup ?3} Pa) exposed Pd(110) surface is explored by H depth profiling with {sup 15}N nuclear reaction analysis (NRA) and thermal desorption spectroscopy (TDS) with isotope (H, D) labeled surface hydrogen. NRA and TDS reveal two types of absorbed hydrogen states of distinctly different depth distributions. Between 80 K and ?145 K a near-surface hydride phase evolving as the TDS ?{sub 1} feature at 160 K forms, which initially extends only several nanometers into depth. On the other hand, a bulk-absorbed hydrogen state develops between 80 K and ?160 K which gives rise to a characteristic ?{sub 3} TDS feature above 190 K. These two absorbed states are populated at spatially separated surface entrance channels. The near-surface hydride is populated through rapid penetration at minority sites (presumably defects) while the bulk-absorbed state forms at regular terraces with much lower probability per site. In both cases, absorption of gas phase hydrogen transfers pre-adsorbed hydrogen atoms below the surface and replaces them at the chemisorption sites by post-dosed hydrogen in a process that requires much less activation energy (<100 meV) than monatomic diffusion of chemisorbed H atoms into subsurface sites. This small energy barrier suggests that the rate-determining step of the absorption process is either H{sub 2} dissociation on the H-saturated Pd surface or a concerted penetration mechanism, where excess H atoms weakly bound to energetically less favorable adsorption sites stabilize themselves in the chemisorption wells while pre-chemisorbed H atoms simultaneously transit into the subsurface. The peculiarity of absorption at regular Pd(110) terraces in comparison to Pd(111) and Pd(100) is discussed.

  4. The absorption and radiation of a tungsten plasma plume during nanosecond laser ablation

    SciTech Connect (OSTI)

    Moscicki, T. Hoffman, J.; Chrzanowska, J.

    2015-10-15

    In this paper, the effect of absorption of the laser beam and subsequent radiation on the dynamics of a tungsten plasma plume during pulsed laser ablation is analyzed. Different laser wavelengths are taken into consideration. The absorption and emission coefficients of tungsten plasma in a pressure range of 0.1–100 MPa and temperature up to 70 000 K are presented. The shielding effects due to the absorption and radiation of plasma may have an impact on the course of ablation. The numerical model that describes the tungsten target heating and the formation of the plasma and its expansion were made for 355 nm and 1064 nm wavelengths of a Nd:YAG laser. The laser beam with a Gaussian profile was focused to a spot size of 0.055 mm{sup 2} with a power density of 1 × 10{sup 9 }W/cm{sup 2} (10 ns full width half maximum pulse duration). The plasma expands into air at ambient pressure of 1 mPa. The use of the shorter wavelength causes faster heating of the target, thus the higher ablation rate. The consequences of a higher ablation rate are slower expansion and smaller dimensions of the plasma plume. The higher plasma temperature in the case of 1064 nm is due to the lower density and lower plasma radiation. In the initial phase of propagation of the plasma plume, when both the temperature and pressure are very high, the dominant radiation is emission due to photo-recombination. However, for a 1064 nm laser wavelength after 100 ns of plasma expansion, the radiation of the spectral lines is up to 46.5% of the total plasma radiation and should not be neglected.

  5. PROBING THE INNER REGIONS OF PROTOPLANETARY DISKS WITH CO ABSORPTION LINE SPECTROSCOPY

    SciTech Connect (OSTI)

    McJunkin, Matthew; France, Kevin; Burgh, Eric B.; Brown, Alexander; Herczeg, Gregory J.; Schindhelm, Eric; Brown, Joanna M.

    2013-03-20

    Carbon monoxide (CO) is the most commonly used tracer of molecular gas in the inner regions of protoplanetary disks. CO can be used to constrain the excitation and structure of the circumstellar environment. Absorption line spectroscopy provides an accurate assessment of a single line of sight through the protoplanetary disk system, giving more straightforward estimates of column densities and temperatures than CO and molecular hydrogen (H{sub 2}) emission line studies. We analyze new observations of ultraviolet CO absorption from the Hubble Space Telescope along the sightlines to six classical T Tauri stars. Gas velocities consistent with the stellar velocities, combined with the moderate-to-high disk inclinations, argue against the absorbing CO gas originating in a fast-moving disk wind. We conclude that the far-ultraviolet observations provide a direct measure of the disk atmosphere or possibly a slow disk wind. The CO absorption lines are reproduced by model spectra with column densities in the range N({sup 12}CO) {approx} 10{sup 16}-10{sup 18} cm{sup -2} and N({sup 13}CO) {approx} 10{sup 15}-10{sup 17} cm{sup -2}, rotational temperatures T{sub rot}(CO) {approx} 300-700 K, and Doppler b-values, b {approx} 0.5-1.5 km s{sup -1}. We use these results to constrain the line-of-sight density of the warm molecular gas (n{sub CO} {approx} 70-4000 cm{sup -3}) and put these observations in context with protoplanetary disk models.

  6. X-ray-absorption study of CuBr at high pressure

    SciTech Connect (OSTI)

    Tranquada, J.M.; Ingalls, R.

    1986-09-15

    The x-ray-absorption spectrum of cuprous bromide has been measured as a function of pressure. The x-ray-absorption near-edge structure proved to be an excellent indicator of high-pressure phase transitions in this material. The normalized ''white-line'' peak heights at both the Cu and Br K-italic edges decreased on entering the tetragonal phase and increased in going to the NaCl structure. The zinc-blende to tetragonal phase transition took place over a very narrow pressure range centered at 46 +- 5 kbar. The transformation from the tetragonal to the NaCl structure, on the other hand, showed a broad mixed-phase region, suggesting a nucleation-and-growth mechanism for the transition. The mixed-phase region was centered at 75 +- 6 kbar. No evidence of a phase between the zinc-blende and tetragonal phases was observed, presumably because it does not exist. Analysis of the extended x-ray-absorption fine-structure (EXAFS) clearly showed that there is no change in coordination in going from the zinc-blende to the tetragonal phase although the nearest-neighbor distance increases slightly. A much larger increase in R-italic/sub 1/ occurs at the transition to the NaCl structure, where the coordination increases from 4 to 6. The mean-square deviation in the nearest-neighbor bond length, sigma/sub 1//sup 2/, appears to be a fairly smooth function of nearest-neighbor distance, decreasing (or increasing) as R-italic/sub 1/ decreases (or increases) more or less independent of structure. Evidence from the literature was presented to suggest that the zinc-blende to tetragonal transition in CuBr (and also CuCl) should occur by shear deformation.

  7. Advanced cogeneration and absorption chillers potential for service to Navy bases. Final report

    SciTech Connect (OSTI)

    Andrews, J.W.; Butcher, T.A.; Leigh, R.W.; McDonald, R.J.; Pierce, B.L.

    1996-04-01

    The US military uses millions of Btu`s of thermal energy to heat, cool and deliver process thermal energy to buildings on military bases, much of which is transmitted through a pipeline system incorporating thousands of miles of pipe. Much of this pipeline system is in disrepair and is nearing the end of its useful life, and the boilers which supply it are old and often inefficient. In 1993, Brookhaven National Laboratory (BNL) proposed to SERDP a three-year effort to develop advanced systems of coupled diesel cogenerators and absorption chillers which would be particularly useful in providing a continuation of the services now provided by increasingly antiquated district systems. In mid-February, 1995, BNL learned that all subsequent funding for our program had been canceled. BNL staff continued to develop the Program Plan and to adhere to the requirements of the Execution Plan, but began to look for ways in which the work could be made relevant to Navy and DoD energy needs even without the extensive development plan formerly envisioned. The entire program was therefore re-oriented to look for ways in which small scale cogeneration and absorption chilling technologies, available through procurement rather than development, could provide some solutions to the problem of deteriorated district heating systems. The result is, we believe, a striking new approach to the provision of building services on military bases: in many cases, serious study should be made of the possibility that the old district heating system should be removed or abandoned, and small-scale cogenerators and absorption chillers should be installed in each building. In the remainder of this Summary, we develop the rationale behind this concept and summarize our findings concerning the conditions under which this course of action would be advisable and the economic benefits which will accrue if it is followed. The details are developed in the succeeding sections of the report.

  8. Absorption properties of type-II InAs/InAsSb superlattices measured by spectroscopic ellipsometry

    SciTech Connect (OSTI)

    Webster, P. T.; Riordan, N. A.; Liu, S.; Zhang, Y.-H.; Johnson, S. R.; Steenbergen, E. H.

    2015-02-09

    Strain-balanced InAs/InAsSb superlattices offer access to the mid- to long-wavelength infrared region with what is essentially a ternary material system at the GaSb lattice constant. The absorption coefficients of InAs/InAsSb superlattices grown by molecular beam epitaxy on (100)-oriented GaSb substrates are measured at room temperature over the 30 to 800?meV photon energy range using spectroscopic ellipsometry, and the miniband structure of each superlattice is calculated using a Kronig-Penney model. The InAs/InAsSb conduction band offset is used as a fitting parameter to align the calculated superlattice ground state transition energy to the measured absorption onset at room temperature and to the photoluminescence peak energy at low temperature. It is observed that the ground state absorption coefficient and transition strength are proportional to the square of the wavefunction overlap and the ground state absorption coefficient approaches a maximum value of around 5780?cm{sup ?1} as the wavefunction overlap approaches 100%. The absorption analysis of these samples indicates that the optical joint density of states is weakly dependent on the period thickness and Sb content of the superlattice, and that wavefunction overlap is the principal design parameter in terms of obtaining strong absorption in these structures.

  9. Experimental investigation for hydrogen and deuterium separation by thermal cycling absorption process

    SciTech Connect (OSTI)

    Guangda, L.; Guoqiang, J.; Cansheng, S.

    1995-10-01

    The Thermal Cycling Absorption Process (TCAP) is a semicontinuous gas chromatographic process for hydrogen isotope separation by which the experiment for hydrogen-deuterium separation has been carried out. The main operating parameters for optimum separation were obtained. On manual operation conditions the concentrations of product and raffinate gas were better than 99.5% simultaneously at a feed rate of 12.0% for a 1:1 hydrogen-deuterium mixture. Besides, TCAP is a good process for trace heavier isotope enriching from hydrogen. The concentration of deuterium can be reduced from 0.5% to less than 50ppm in hydrogen in ten cycles. 5 refs., 4 figs.

  10. X-ray absorption spectroscopy studies of electrochemically deposited thin oxide films.

    SciTech Connect (OSTI)

    Balasubramanian, M.

    1998-06-02

    We have utilized ''in situ'' X-ray Absorption Fine Structure Spectroscopy to investigate the structure and composition of thin oxide films of nickel and iron that have been prepared by electrodeposition on a graphite substrate from aqueous solutions. The films are generally disordered. Structural information has been obtained from the analysis of the data. We also present initial findings on the local structure of heavy metal ions, e.g. Sr and Ce, incorporated into the electrodeposited nickel oxide films. Our results are of importance in a number of technological applications, among them, batteries, fuel cells, electrochromic and ferroelectric materials, corrosion protection, as well as environmental speciation and remediation.

  11. Emission and Absorption Spectroscopy of Carbon Arc Plasma during Formation of Carbon Magnetic Encapsulates

    SciTech Connect (OSTI)

    Lange, H.; Labedz, O.; Huczko, A.; Bystrzejewski, M.

    2011-11-29

    Plasma diagnostics of carbon arc discharge under conditions of carbon magnetic encapsulates formation was performed by emission and absorption spectroscopy. Content of C{sub 2} and Fe species, rotational temperatures of excited (d {sup 3} product {sub g}) and non-excited (a {sup 3} product {sub u}) states, and excitation temperatures of a {sup 5}F and a {sup 3}F levels relatively to the a {sup 5}D level of Fe atoms were determined. The results pointed to a non-equilibrium state of carbon arc plasma under prevailing discharge conditions.

  12. CNG process, a new approach to physical-absorption acid-gas removal

    SciTech Connect (OSTI)

    Hise, R.E.; Massey, L.G.; Adler, R.J.; Brosilow, C.B.; Gardner, N.C.; Brown, W.R.; Cook, W.J.; Petrik, M.

    1982-01-01

    The CNG acid gas removal process embodies three novel features: (1) scrubbing with liquid carbon dioxide to remove all sulfurous molecules and other trace contaminants; (2) triple-point crystallization of carbon dioxide to concentrate sulfurous molecules and produce pure carbon dioxide; and (3) absorption of carbon dioxide with a slurry of solid carbon dioxide in organic carrier liquid. The CNG process is discussed and contrasted with existing acid gas removal technology as represented by the Benfield, Rectisol, and Selexol acid gas removal processes.

  13. Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling

    SciTech Connect (OSTI)

    Barnett, J. M.; Cullinan, Valerie I.; Barnett, Debra S.; Trang-Le, Truc LT; Bliss, Mary; Greenwood, Lawrence R.; Ballinger, Marcel Y.

    2009-02-17

    Since the mid-1980s, Pacific Northwest National Laboratory (PNNL) has used a value of 0.85 as the correction factor for self absorption of activity for particulate radioactive air samples collected from building exhaust for environmental monitoring. This value accounts for activity that cannot be detected by direct counting of alpha and beta particles. Emissions can be degraded or blocked by filter fibers for particles buried in the filter material or by inactive dust particles collected with the radioactive particles. These filters are used for monitoring air emissions from PNNL stacks for radioactive particles. This paper describes an effort to re-evaluate self-absorption effects in particulate radioactive air sample filters (Versapor 3000, 47 mm diameter) used at PNNL. There were two methods used to characterize the samples. Sixty samples were selected from the archive for acid digestion to compare the radioactivity measured by direct gas-flow proportional counting of filters to the results obtained after acid digestion of the filter and counting again by gas-flow proportional detection. Thirty different sample filters were selected for visible light microscopy to evaluate filter loading and particulate characteristics. Mass-loading effects were also considered. Filter ratios were calculated by dividing the initial counts by the post-digestion counts with the expectation that post-digestion counts would be higher because digestion would expose radioactivity embedded in the filter in addition to that on top of the filter. Contrary to expectations, the post digestion readings were almost always lower than initial readings and averaged approximately half the initial readings for both alpha and beta activity. Before and after digestion readings appeared to be related to each other, but with a low coefficient of determination (R^2) value. The ratios had a wide range of values indicating that this method did not provide sufficient precision to quantify self-absorption

  14. Measurement of Hydrogen Absorption in Ternary Alloys with Volumetric (Sieverts Loop) Techniques

    SciTech Connect (OSTI)

    Aceves, S.

    2015-10-26

    The Sieverts loop is an inexpensive, robust and reliable methodology for calculating hydrogen absorption in materials [1]. In this approach, we start by storing a sample of the material being tested in the volume Vcell (Figure 1) and initiate the process by producing a high vacuum in the system while the material sample is heated to eliminate (most of) the hydrogen and other impurities previously absorbed. The system typically operates isothermally, with the volume Vref at ambient temperature and the sample at a temperature of interest – high enough to liquefy the alloy for the current application to nuclear fusion.

  15. Determination of heavy metals in solid emission and immission samples using atomic absorption spectroscopy

    SciTech Connect (OSTI)

    Fara, M.; Novak, F.

    1995-12-01

    Both flame and electrothermal methods of atomic absorption spectroscopy (AAS) have been applied to the determination of Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, TI, Se, V and Zn in emission and emission (deposition) samples decomposed in open PTFE test-tubes by individual fuming-off hydrofluoric, perchloroic and nitric acid. An alternative hydride technique was also used for As and Se determination and Hg was determined using a self-contained AAS analyzer. A graphite platform proved good to overcome non-spectral interferences in AAS-ETA. Methods developed were verified by reference materials (inc. NBS 1633a).

  16. Visible absorption spectra of crystal violet in supercritical ethane - methanol solution.

    SciTech Connect (OSTI)

    Dimitrijevic, N. M.; Takahashi, K.; Jonah, C. D.; Chemistry

    2002-11-01

    The effects of concentration and mole fraction of methanol in supercritical ethane on the absorption spectra of crystal violet (CV) were examined. Keeping the concentration of CV in the cell constant at 50 {mu}mol l{sup -1}, both the methanol concentration (from 0.4 to 1.2 mol l{sup -1}) and pressure of ethane (from 60 to 150 bar) were varied. The degree of solvation of CV depends both on the mole fraction and concentration of cosolvent. The dimerization of CV was found to decrease with pressure, and with the ratio between methanol and CV concentrations.

  17. Surface extended x-ray absorption fine structure of low-Z absorbates using fluorescence detection

    SciTech Connect (OSTI)

    Stoehr, J.; Kollin, E.B.; Fischer, D.A.; Hastings, J.B.; Zaera, F.; Sette, F.

    1985-05-01

    Comparison of x-ray fluorescence yield (FY) and electron yield surface extended x-ray absorption fine structure spectra above the S K-edge for c(2 x 2) S on Ni(100) reveals an order of magnitude higher sensitivity of the FY technique. Using FY detection, thiophene (C/sub 4/H/sub 4/S) chemisorption on Ni(100) is studied with S coverages down to 0.08 monolayer. The molecule dissociates at temperatures as low as 100K by interaction with fourfold hollow Ni sites. Blocking of these sites by oxygen leaves the molecule intact.

  18. Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Levantino, M.; Lemke, H. T.; Schirò, G.; Glownia, M.; Cupane, A.; Cammarata, M.

    2015-07-01

    We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (~70 fs) relaxation preceding a slower (~400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix.

  19. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  20. Present knowledge about specific absorption rates inside a human body exposed to radiofrequency electromagnetic fields

    SciTech Connect (OSTI)

    Garn, J.; Gabriel, C.

    1995-02-01

    We have compiled results of scientific investigations about the relationship between external field-strengths and specific absorption rates inside the human body. The data were normalized to SAR-values that form the basis for current safety standards. Results were compared to exposure limits given in these standard. This comparison should serve as a reference for the selection of reliable reference levels for personal protection against thermal effects in radiofrequency electromagnetic fields. The need to measure and monitor ankle/wrist currents to protect some exposed workers is explained. The study has also highlighted a scarcity of dosimetric data at frequencies below 3 MHz. 20 refs., 7 figs.

  1. Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

    SciTech Connect (OSTI)

    Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

    2015-02-01

    The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production systems footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

  2. Triple-effect absorption refrigeration system with double-condenser coupling

    DOE Patents [OSTI]

    DeVault, R.C.; Biermann, W.J.

    1993-04-27

    A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

  3. Triple-effect absorption refrigeration system with double-condenser coupling

    DOE Patents [OSTI]

    DeVault, Robert C.; Biermann, Wendell J.

    1993-01-01

    A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

  4. Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopya)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Levantino, M.; Lemke, H. T.; Schir, G.; Glownia, M.; Cupane, A.; Cammarata, M.

    2015-07-01

    We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (~70 fs) relaxation preceding a slower (~400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix.

  5. Total absorption spectroscopy study of ?Rb decay: A major contributor to reactor antineutrino spectrum shape [Total absorption spectroscopy study of ?Rb: A major contributor to reactor antineutrino flux

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sonzogni, A.; Zakari-Issoufou, A. -A.; Fallot, M.; Porta, A.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Bui, V. M.; Cormon, S.; et al

    2015-03-09

    The accurate determination of the emitted reactor antineutrino flux is still a major challenge for actual and future neutrino experiments at reactors, especially after the evidence of a disagreement between the measured antineutrino energy spectrum by Double Chooz, Daya Bay, and Reno and calculated antineutrino spectra obtained from the conversion of the unique integral beta spectra measured at the ILL reactor. Using nuclear data to compute reactor antineutrino spectra may help understanding this bias, with the study of the underlying nuclear physics. Summation calculations allow identifying a list of nuclei that contribute importantly to the antineutrino energy spectra emitted aftermorethe fission of ?,?Pu and ?,?U, and whose beta decay properties might deserve new measurements. Among these nuclei, ?Rb exhausts by itself about 16% of of the antineutrino energy spectrum emitted by Pressurized Water Reactors in the 5 to 8 MeV range. In this Letter, we report new Total Absorption Spectroscopy (TAS) results for this important contributor. The obtained beta feeding from ?Rb shows beta intensity unobserved before in the 4.5 to 5.5 MeV energy region and gives a ground state to ground state branch of 87.5 % 3%. These new data induce a dramatic change in recent summation calculations where a 51% GS to GS branch was considered for ?Rb, increasing the summation antineutrino spectrum in the region nearby the observed bias.The new data still have an important impact on other summation calculations in which more recent data were consideredless

  6. High energy resolution five-crystal spectrometer for high quality fluorescence and absorption measurements on an x-ray absorption spectroscopy beamline

    SciTech Connect (OSTI)

    Llorens, Isabelle; Lahera, Eric; Delnet, William; Proux, Olivier; Dermigny, Quentin; Gelebart, Frederic; Morand, Marc; Shukla, Abhay; Bardou, Nathalie; Ulrich, Olivier; and others

    2012-06-15

    Fluorescence detection is classically achieved with a solid state detector (SSD) on x-ray absorption spectroscopy (XAS) beamlines. This kind of detection however presents some limitations related to the limited energy resolution and saturation. Crystal analyzer spectrometers (CAS) based on a Johann-type geometry have been developed to overcome these limitations. We have tested and installed such a system on the BM30B/CRG-FAME XAS beamline at the ESRF dedicated to the structural investigation of very dilute systems in environmental, material and biological sciences. The spectrometer has been designed to be a mobile device for easy integration in multi-purpose hard x-ray synchrotron beamlines or even with a laboratory x-ray source. The CAS allows to collect x-ray photons from a large solid angle with five spherically bent crystals. It will cover a large energy range allowing to probe fluorescence lines characteristic of all the elements from Ca (Z = 20) to U (Z = 92). It provides an energy resolution of 1-2 eV. XAS spectroscopy is the main application of this device even if other spectroscopic techniques (RIXS, XES, XRS, etc.) can be also achieved with it. The performances of the CAS are illustrated by two experiments that are difficult or impossible to perform with SSD and the complementarity of the CAS vs SSD detectors is discussed.

  7. The dependence of C IV broad absorption line properties on accompanying Si IV and Al III absorption: relating quasar-wind ionization levels, kinematics, and column densities

    SciTech Connect (OSTI)

    Filiz Ak, N.; Brandt, W. N.; Schneider, D. P.; Trump, J. R.; Hall, P. B.; Anderson, S. F.; Hamann, F.; Myers, Adam D.; Pâris, I.; Petitjean, P.; Ross, Nicholas P.; Shen, Yue; York, Don

    2014-08-20

    We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are present at corresponding velocities, indicating that the line of sight intercepts at least some lower ionization gas. We derive a number of observational results for C IV BALs separated according to the presence or absence of accompanying lower ionization transitions, including measurements of composite profile shapes, equivalent width (EW), characteristic velocities, composite variation profiles, and EW variability. We also measure the correlations between EW and fractional-EW variability for C IV, Si IV, and Al III. Our measurements reveal the basic correlated changes between ionization level, kinematics, and column density expected in accretion-disk wind models; e.g., lines of sight including lower ionization material generally show deeper and broader C IV troughs that have smaller minimum velocities and that are less variable. Many C IV BALs with no accompanying Si IV or Al III BALs may have only mild or no saturation.

  8. Millisecond Kinetics of Nanocrystal Cation Exchange UsingMicrofluidic X-ray Absorption Spectroscopy

    SciTech Connect (OSTI)

    Chan, Emory M.; Marcus, Matthew A.; Fakra, Sirine; Elnaggar,Mariam S.; Mathies, Richard A.; Alivisatos, A. Paul

    2007-05-07

    We describe the use of a flow-focusing microfluidic reactorto measure the kinetics of theCdSe-to-Ag2Se nanocrystal cation exchangereaction using micro-X-ray absorption spectroscopy (mu XAS). The smallmicroreactor dimensions facilitate the millisecond mixing of CdSenanocrystal and Ag+ reactant solutions, and the transposition of thereaction time onto spatial coordinates enables the in situ observation ofthe millisecond reaction with mu XAS. XAS spectra show the progression ofCdSe nanocrystals to Ag2Se over the course of 100 ms without the presenceof long-lived intermediates. These results, along with supporting stoppedflow absorption experiments, suggest that this nanocrystal cationexchange reaction is highly efficient and provide insight into how thereaction progresses in individual particles. This experiment illustratesthe value and potential of in situ microfluidic X-ray synchrotrontechniques for detailed studies of the millisecond structuraltransformations of nanoparticles and other solution-phase reactions inwhich diffusive mixing initiates changes in local bond structures oroxidation states.

  9. Continuum absorption in the vicinity of the toroidicity-induced Alfvén gap

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, M.; Breizman, B. N.; Zheng, L. J.; Chen, Eugene Y.

    2015-12-04

    Excitation of Alfvén modes is commonly viewed as a concern for energetic particle confinement in burning plasmas. The 3.5 MeValpha particles produced by fusion may be affected as well as other fast ions in both present and future devices. Continuum damping of such modes is one of the key factors that determine their excitation thresholds and saturation levels. This work examines the resonant dissipative response of the Alfvén continuum to an oscillating driving current when the driving frequency is slightly outside the edges of the toroidicity-induced spectral gap. The problem is largely motivated by the need to describe the continuummore » absorption in the frequency sweeping events. Akey element of this problem is the negative interference of the two closely spaced continuum crossing points.Weexplain why the lower and upper edges of the gap can have very different continuum absorption features. Lastly, the difference is associated with an eigenmode whose frequency can be arbitrarily close to the upper edge of the gap whereas the lower edge of the gap is always a finite distance away from the closest eigenmode.« less

  10. Attosecond transient absorption probing of electronic superpositions of bound states in neon. Detection of quantum beats

    SciTech Connect (OSTI)

    Beck, Annelise R; Bernhardt, Birgitta; Warrick, Erika R.; Wu, Mengxi; Chen, Shaohao; Gaarde, Mette B.; Schafer, Kenneth J.; Neumark, Daniel M.; Leone, Stephen R.

    2014-11-07

    Electronic wavepackets composed of multiple bound excited states of atomic neon lying between 19.6 and 21.5 eV are launched using an isolated attosecond pulse. Individual quantum beats of the wavepacket are detected by perturbing the induced polarization of the medium with a time-delayed few-femtosecond near-infrared (NIR) pulse via coupling the individual states to multiple neighboring levels. All of the initially excited states are monitored simultaneously in the attosecond transient absorption spectrum, revealing Lorentzian to Fano lineshape spectral changes as well as quantum beats. The most prominent beating of the several that were observed was in the spin–orbit split 3d absorption features, which has a 40 femtosecond period that corresponds to the spin–orbit splitting of 0.1 eV. The few-level models and multilevel calculations confirm that the observed magnitude of oscillation depends strongly on the spectral bandwidth and tuning of the NIR pulse and on the location of possible coupling states.

  11. Optical absorption and stimulated emission of neodymium in yttrium lithium fluoride

    SciTech Connect (OSTI)

    Ryan, J.R.; Beach, R. )

    1992-10-01

    A spectroscopic investigation of Nd{sup 3+} in yttrium lithium fluoride was performed. Spectrally and orientationally resolved cross sections for the {sup 4}{ital F}{sub 3/2}--{sup 4}{ital I}{sub 11/2} and {sup 4}{ital F}{sub 3/2}--{sup 4}{ital I}{sub 9/2} transitions are presented. We applied the Judd--Ofelt theory to measured absorption spectra to determine the orientation-averaged intensity parameters {Omega}{sub 2}=0.362{times}10{sup {minus}20} cm{sup 2}, {Omega}{sub 4}=4.02{times}10{sup {minus}20} cm{sup 2}, and {Omega}{sub 6}=4.84{times}10{sup {minus}20} cm{sup 2}. Using these intensity parameters, we predicted the radiative lifetime of the metastable {sup 4}{ital F}{sub 3/2} state to be 525 {mu}s, in excellent agreement with measured {sup 4}{ital F}{sub 3/2} decay signatures. Finally, absorption cross-section data are presented that will be of interest to the laser designer.

  12. Numerical simulation of solar heat absorption within indoor space by means of composite grid method

    SciTech Connect (OSTI)

    Omori, Toshiaki; Murakami, Shuzo; Kato, Shinsuke

    1997-12-31

    This paper describes the method for numerical simulation of solar radiation entering indoor spaces through fenestration. The proposed method can systematically deal with the interception of sunlight by buildings in the outdoor space and obstacles in the indoor space by tracing a large number of particles directed toward the sun. Configuration factors from the fenestration to the sky are also three-dimensionally treated by accounting for outdoor geometries. Distribution of the solar heat absorption in the indoor space is calculated by assuming radiation equilibrium. After the solar heat absorption analysis is carried out, heat transfer analysis in the space is conducted taking account of longwave radiation, convective heat transfer, thermal conduction, and cooling/heating by air conditioning. Then, the indoor thermal environment is evaluated using the resulting temperature distribution of air and indoor surfaces. To evaluate the applicability of these procedures, the thermal environment in a model hall with large glass windows and an overhang is predicted. The analyzed hall is assumed to be located near a tall building.

  13. Broadband optical absorption by tunable Mie resonances in silicon nanocone arrays

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Z. Y.; Zhang, R. J.; Wang, S. Y.; Lu, M.; Chen, X.; Zheng, Y. X.; Chen, L. Y.; Ye, Z.; Wang, C. Z.; Ho, K. M.

    2015-01-15

    Nanostructure arrays such as nanowire, nanopillar, and nanocone arrays have been proposed to be promising antireflection structures for photovoltaic applications due to their great light trapping ability. In this paper, the optical properties of Si nanopillar and nanocone arrays in visible and infrared region were studied by both theoretical calculations and experiments. The results show that the Mie resonance can be continuously tuned across a wide range of wavelength by varying the diameter of the nanopillars. However, Si nanopillar array with uniform diameter exhibits only discrete resonance mode, thus can't achieve a high broadband absorption. On the other hand, themore » Mie resonance wavelength in a Si nanocone array can vary continuously as the diameters of the cross sections increase from the apex to the base. Therefore Si nanocone arrays can strongly interact with the incident light in the broadband spectrum and the absorbance by Si nanocone arrays is higher than 95% over the wavelength from 300 to 2000 nm. In addition to the Mie resonance, the broadband optical absorption of Si nanocone arrays is also affected by Wood-Rayleigh anomaly effect and metal impurities introduced in the fabrication process.« less

  14. A table-top femtosecond time-resolved soft x-ray transient absorption spectrometer

    SciTech Connect (OSTI)

    Leone, Stephen; Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E.; Leone, Stephen R.

    2008-05-21

    A laser-based, table-top instrument is constructed to perform femtosecond soft x-ray transient absorption spectroscopy. Ultrashort soft x-ray pulses produced via high-order harmonic generation of the amplified output of a femtosecond Ti:sapphire laser system are used to probe atomic core-level transient absorptions in atoms and molecules. The results provide chemically specific, time-resolved dynamics with sub-50-fs time resolution. In this setup, high-order harmonics generated in a Ne-filled capillary waveguide are refocused by a gold-coated toroidal mirror into the sample gas cell, where the soft x-ray light intersects with an optical pump pulse. The transmitted high-order harmonics are spectrally dispersed with a home-built soft x-ray spectrometer, which consists of a gold-coated toroidal mirror, a uniform-line spaced plane grating, and a soft x-ray CCD camera. The optical layout of the instrument, design of the soft x-ray spectrometer, and spatial and temporal characterization of the high-order harmonics are described. Examples of static and time-resolved photoabsorption spectra collected on this apparatus are presented.

  15. Institutional project summary University of Redlands direct fired gas absorption chiller system

    SciTech Connect (OSTI)

    Tanner, G.R.

    1996-05-01

    The University of Redlands, located in the California Inland Empire City of Redlands supplies six campus building with chilled and hot water for cooling and space heating from a centrally located Mechanical Center. The University was interested in lowering chilled water production costs and eliminating Ozone depleting chloroflourocarbon (CFC) refrigerants in addition to adding chiller capacity for future building to be added to the central plant piping {open_quotes}loop{close_quotes}. After initially providing a feasibility study of chiller addition alternatives and annual hourly load models, GRT & Associates, Inc. (GRT) provided design engineering for the installation of a 500 Ton direct gas fired absorption chiller addition to the University of Redland`s mechanical center. Based on the feasibility study and energy consumption tests done after the new absorption chiller was added, the university estimates annual energy cost saving versus the existing electric chiller is approximately $65,000 per year. Using actual construction costs, the simple before tax payback period for the project is six years.

  16. Study of the absorption coefficient of alpha particles to lower hybrid waves in tokamak

    SciTech Connect (OSTI)

    Wang, Jianbing Zhang, Xianmei Yu, Limin Zhao, Xiang

    2014-02-12

    Part of the energy of the Lower Hybrid (LH) waves may be absorbed by the ? particles via the so-called perpendicular landau damping mechanism, which depends on various parameters of fusion reactors and the LH waves. In this article, we calculate the absorption coefficient ?{sub ?} of LH waves due to ? particles. Results show that, the ?{sub ?} increases with the parallel refraction index n{sub ?} while deceases with increasing the frequency of LH waves ?{sub LH} over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption, and there is a peak value of ?{sub ?} when n{sub e}?810{sup 19}m{sup ?3} for ITER-like scenario. The thermal corrections to the cold plasma dispersion relation will change the damping rate to a certain extent under some specific conditions. We have also evaluated the fraction of LH power absorbed by the alpha particles, ? ? 0.47% and 4.1% for an LH frequency of 5 GHz and 3.7 GHz respectively for ITER-like scenario. This work gives the effective reference for the choice of parameters of future fusion reactors.

  17. Broadband optical absorption by tunable Mie resonances in silicon nanocone arrays

    SciTech Connect (OSTI)

    Wang, Z. Y.; Zhang, R. J.; Wang, S. Y.; Lu, M.; Chen, X.; Zheng, Y. X.; Chen, L. Y.; Ye, Z.; Wang, C. Z.; Ho, K. M.

    2015-01-15

    Nanostructure arrays such as nanowire, nanopillar, and nanocone arrays have been proposed to be promising antireflection structures for photovoltaic applications due to their great light trapping ability. In this paper, the optical properties of Si nanopillar and nanocone arrays in visible and infrared region were studied by both theoretical calculations and experiments. The results show that the Mie resonance can be continuously tuned across a wide range of wavelength by varying the diameter of the nanopillars. However, Si nanopillar array with uniform diameter exhibits only discrete resonance mode, thus can't achieve a high broadband absorption. On the other hand, the Mie resonance wavelength in a Si nanocone array can vary continuously as the diameters of the cross sections increase from the apex to the base. Therefore Si nanocone arrays can strongly interact with the incident light in the broadband spectrum and the absorbance by Si nanocone arrays is higher than 95% over the wavelength from 300 to 2000 nm. In addition to the Mie resonance, the broadband optical absorption of Si nanocone arrays is also affected by Wood-Rayleigh anomaly effect and metal impurities introduced in the fabrication process.

  18. Absorption and Phase Contrast X-Ray Imaging in Paleontology Using Laboratory and Synchrotron Sources

    SciTech Connect (OSTI)

    Bidola, Pidassa; Stockmar, Marco; Achterhold, Klaus; Pfeiffer, Franz; Pacheco, Mirian L.A.F.; Soriano, Carmen; Beckmann, Felix; Herzen, Julia

    2015-10-01

    X-ray micro-computed tomography (CT) is commonly used for imaging of samples in biomedical or materials science research. Owing to the ability to visualize a sample in a nondestructive way, X-ray CT is perfectly suited to inspect fossilized specimens, which are mostly unique or rare. In certain regions of the world where important sedimentation events occurred in the Precambrian geological time, several fossilized animals are studied to understand questions related to their origin, environment, and life evolution. This article demonstrates the advantages of applying absorption and phase-contrast CT on the enigmatic fossil Corumbella werneri, one of the oldest known animals capable of building hard parts, originally discovered in Corumba (Brazil). Different tomographic setups were tested to visualize the fossilized inner structures: a commercial laboratory-based CT device, two synchrotron-based imaging setups using conventional absorption and propagation-based phase contrast, and a commercial X-ray microscope with a lens-coupled detector system, dedicated for radiography and tomography. Based on our results we discuss the strengths and weaknesses of the different imaging setups for paleontological studies.

  19. Method and apparatus for determination of temperature, neutron absorption cross section and neutron moderating power

    DOE Patents [OSTI]

    Vagelatos, Nicholas; Steinman, Donald K.; John, Joseph; Young, Jack C.

    1981-01-01

    A nuclear method and apparatus determines the temperature of a medium by injecting fast neutrons into the medium and detecting returning slow neutrons in three first energy ranges by producing three respective detection signals. The detection signals are combined to produce three derived indicia each systematically related to the population of slow neutrons returning from the medium in a respective one of three second energy ranges, specifically exclusively epithermal neutrons, exclusively substantially all thermal neutrons and exclusively a portion of the thermal neutron spectrum. The derived indicia are compared with calibration indicia similarly systematically related to the population of slow neutrons in the same three second energy ranges returning from similarly irradiated calibration media for which the relationships temperature, neutron absorption cross section and neutron moderating power to such calibration indicia are known. The comparison indicates the temperature at which the calibration indicia correspond to the derived indicia and consequently the temperature of the medium. The neutron absorption cross section and moderating power of the medium can be identified at the same time.

  20. Calculation of the spatial resolution in two-photon absorption spectroscopy applied to plasma diagnosis

    SciTech Connect (OSTI)

    Garcia-Lechuga, M.; Fuentes, L. M.; Grützmacher, K.; Pérez, C. Rosa, M. I. de la

    2014-10-07

    We report a detailed characterization of the spatial resolution provided by two-photon absorption spectroscopy suited for plasma diagnosis via the 1S-2S transition of atomic hydrogen for optogalvanic detection and laser induced fluorescence (LIF). A precise knowledge of the spatial resolution is crucial for a correct interpretation of measurements, if the plasma parameters to be analysed undergo strong spatial variations. The present study is based on a novel approach which provides a reliable and realistic determination of the spatial resolution. Measured irradiance distribution of laser beam waists in the overlap volume, provided by a high resolution UV camera, are employed to resolve coupled rate equations accounting for two-photon excitation, fluorescence decay and ionization. The resulting three-dimensional yield distributions reveal in detail the spatial resolution for optogalvanic and LIF detection and related saturation due to depletion. Two-photon absorption profiles broader than the Fourier transform-limited laser bandwidth are also incorporated in the calculations. The approach allows an accurate analysis of the spatial resolution present in recent and future measurements.

  1. CO{sub 2}-philic oligomers as novel solvents for CO{sub 2} absorption

    SciTech Connect (OSTI)

    Miller, Matthew B; Luebke, David R; Enick, Robert M

    2010-01-01

    Desirable properties for an oligomeric CO{sub 2}-capture solvent in an integrated gasification combined cycle (IGCC) plant include high selectivity for CO{sub 2} over H{sub 2} and water, low viscosity, low vapor pressure, low cost, and minimal environmental, health, and safety impacts. The neat solvent viscosity and solubility of CO{sub 2}, measured via bubble-point loci and presented on a pressure−composition diagram (weight basis), and water miscibility in CO{sub 2}-philic solvents have been determined and compared to results obtained with Selexol, a commercial oligomeric CO{sub 2} solvent. The solvents tested include polyethyleneglycol dimethylether (PEGDME), polypropyleneglycol dimethylether (PPGDME), polypropyleneglycol diacetate (PPGDAc), polybutyleneglycol diacetate (PBGDAc), polytetramethyleneetherglycol diacetate (PTMEGDAc), glyceryl triacetate (GTA), polydimethyl siloxane (PDMS), and perfluorpolyether (PFPE) that has a perfluorinated propyleneglycol monomer unit. Overall, PDMS and PPGDME are the best oligomeric solvents tested and exhibit properties that make them very promising alternatives for the selective absorption of CO{sub 2} from a mixed gas stream, especially if the absorption of water is undesirable.

  2. Tailoring of absorption edge by thermal annealing in tin oxide thin films

    SciTech Connect (OSTI)

    Thakur, Anup; Gautam, Sanjeev; Kumar, Virender; Chae, K. H.; Lee, Ik-Jae; Shin, Hyun Joon

    2015-05-15

    Tin oxide (SnO{sub 2}) thin films were deposited by radio-frequency (RF) magnetron sputtering on silicon and glass substrates in different oxygen-to-argon gas-flow ratio (O{sub 2}-to-Ar = 0%, 10%, 50%). All films were deposited at room temperature and fixed working pressures, 10 mTorr. The X-ray diffraction (XRD) measurement suggests that all films were crystalline in nature except film deposited in argon environment. Thin films were annealed in air at 200 C, 400 C and 600 C for two hours. All films were highly transparent except the film deposited only in the argon environment. It was also observed that transparency was improved with annealing due to decrease in oxygen vacancies. Atomic force microscopy (AFM), results showed that the surface of all the films were highly flat and smooth. Blue shift was observed in the absorption edge with annealing temperature. It was also observed that there was not big change in the absorption edge with annealing for films deposited in 10% and 50% oxygen-to-argon gas-flow ratio.

  3. Propagation and absorption of high-intensity femtosecond laser radiation in diamond

    SciTech Connect (OSTI)

    Kononenko, V V; Konov, V I; Gololobov, V M; Zavedeev, E V

    2014-12-31

    Femtosecond interferometry has been used to experimentally study the photoexcitation of the electron subsystem of diamond exposed to femtosecond laser pulses of intensity 10{sup 11} to 10{sup 14} W cm{sup -2}. The carrier concentration has been determined as a function of incident intensity for three harmonics of a Ti : sapphire laser (800, 400 and 266 nm). The results demonstrate that, in a wide range of laser fluences (up to those resulting in surface and bulk graphitisation), a well-defined multiphoton absorption prevails. We have estimated nonlinear absorption coefficients for pulsed radiation at λ = 800 nm (four-photon transition) and at 400 and 266 nm (indirect and direct two-photon transitions, respectively). It has also been shown that, at any considerable path length of a femtosecond pulse in diamond (tens of microns or longer), the laser beam experiences a severe nonlinear transformation, determining the amount of energy absorbed by the lattice, which is important for the development of technology for diamond photostructuring by ultrashort pulses. The competition between wave packet self-focusing and the plasma defocusing effect is examined as a major mechanism governing the propagation of intense laser pulses in diamond. (interaction of laser radiation with matter. laser plasma)

  4. Continuum absorption in the vicinity of the toroidicity-induced Alfvén gap

    SciTech Connect (OSTI)

    Li, M.; Breizman, B. N.; Zheng, L. J.; Chen, Eugene Y.

    2015-12-04

    Excitation of Alfvén modes is commonly viewed as a concern for energetic particle confinement in burning plasmas. The 3.5 MeValpha particles produced by fusion may be affected as well as other fast ions in both present and future devices. Continuum damping of such modes is one of the key factors that determine their excitation thresholds and saturation levels. This work examines the resonant dissipative response of the Alfvén continuum to an oscillating driving current when the driving frequency is slightly outside the edges of the toroidicity-induced spectral gap. The problem is largely motivated by the need to describe the continuum absorption in the frequency sweeping events. Akey element of this problem is the negative interference of the two closely spaced continuum crossing points.Weexplain why the lower and upper edges of the gap can have very different continuum absorption features. Lastly, the difference is associated with an eigenmode whose frequency can be arbitrarily close to the upper edge of the gap whereas the lower edge of the gap is always a finite distance away from the closest eigenmode.

  5. Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT

    SciTech Connect (OSTI)

    Brabec, Jiri; Lin, Lin; Shao, Meiyue; Govind, Niranjan; Yang, Chao; Saad, Yousef; Ng, Esmond

    2015-10-06

    We present two iterative algorithms for approximating the absorption spectrum of molecules within linear response of time-dependent density functional theory (TDDFT) framework. These methods do not attempt to compute eigenvalues or eigenvectors of the linear response matrix. They are designed to approximate the absorption spectrum as a function directly. They take advantage of the special structure of the linear response matrix. Neither method requires the linear response matrix to be constructed explicitly. They only require a procedure that performs the multiplication of the linear response matrix with a vector. These methods can also be easily modified to efficiently estimate the density of states (DOS) of the linear response matrix without computing the eigenvalues of this matrix. We show by computational experiments that the methods proposed in this paper can be much more efficient than methods that are based on the exact diagonalization of the linear response matrix. We show that they can also be more efficient than real-time TDDFT simulations. We compare the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost.

  6. Probing variations in fundamental constants with radio and optical quasar absorption-line observations.

    SciTech Connect (OSTI)

    Tzanavaris, P.; Murphy, M. T.; Webb, J. K.; Flambaum, V. V.; Curran, S. J.; Physics; Univ. of New South Wales; Inst. of Astronomy

    2007-01-01

    Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x {triple_bond} {alpha}{sup 2}g{sub p}{mu}, where {alpha} is the fine structure constant, g{sub p} the proton g-factor and {mu} {triple_bond} m{sub e}/m{sub p} is the electron-to-proton mass ratio. We find <{Delta}x/x>{sub total}{sup weighted} = (0.63 {+-} 0.99) x 10{sup -5} over a redshift range 0.23 {le} z{sub abs} {le} 2.35 which corresponds to look-back times of 2.7-10.5 billion years. A linear fit against look-back time, tied to {Delta}x/x = 0 at z = 0, gives a best-fitting rate of change of {dot x}/x = (-0.6 {+-} 1.2) x 10{sup -5} yr{sup -1}. We find no evidence for strong angular variations in x across the sky. Our sample is much larger than most previous samples and demonstrates that intrinsic line-of-sight velocity differences between the 21-cm and UV absorption redshifts, which have a random sign and magnitude in each absorption system, limit our precision. The data directly imply that the average magnitude of this difference is {Delta}v{sub los}-6 km s{sup -1}. Combining our {Delta}x/x measurement with absorption-line constraints on {alpha}-variation yields strong limits on the variation of {mu}. Our most conservative estimate, obtained by assuming no variations in {alpha} or g{sub p} is simply {Delta}{mu}/{mu} = <{Delta}x/x>{sub total}{sup weighted}. If we use only the four high-redshift absorbers in our sample, we obtain {Delta}{mu}/{mu} = (0.58 {+-} 1.95) x 10{sup -5}, which agrees (2{sigma}) with recent, more direct estimates from two absorption systems containing molecular hydrogen, also at high redshift, and which have hinted at a possible {mu}-variation, {Delta}{mu}/{mu} = (-2.0 {+-} 0.6) x 10{sup -5}. Our method of constraining {Delta}{mu}/{mu} is completely independent from the molecular hydrogen observations. If we include the low-redshift systems, our {Delta}{mu}/{mu} result differs significantly from the high

  7. Evidence for active galactic nucleus feedback in the broad absorption lines and reddening of MRK 231 {sup ,}

    SciTech Connect (OSTI)

    Leighly, Karen M.; Baron, Eddie; Lucy, Adrian B. [Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States); Terndrup, Donald M. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Dietrich, Matthias [Department of Physics and Astronomy, Ohio University, Clippinger Labs 251B, Athens, OH 45701 (United States); Gallagher, Sarah C. [Department of Physics and Astronomy, The University of Western Ontario, London, ON, N6A 3K7 (Canada)

    2014-06-20

    We present the first J-band spectrum of Mrk 231, which reveals a large He I* ?10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ?100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.

  8. Characteristics of anomalous skin effect and evolution of power absorption regions in a cylindrical radio frequency inductively coupled plasma

    SciTech Connect (OSTI)

    Ding, Z. F.; Sun, B.; Huo, W. G.

    2015-06-15

    In a low-pressure radio-frequency (13.56 MHz), inductively coupled argon plasma generated by a normal cylindrical rf coil, electric field, current density, and absorbed power density is calculated from magnetic field measured with a phase-resolved magnetic probe. The anomalous skin effect (ASE) for the cylindrical rf coil is compared to those previously reported for the planar and re-entrant cylindrical rf coils. Physical reasons for our observed characteristics of ASE are presented. With the increasing discharge power, the size and the number of negative and positive power absorption regions evolve into several distinct patterns. For the low discharge power (at 156.9 W), there is one area of positive and one area of negative power absorption in the radial direction. For the medium discharge power (279 W–683.5 W), there are two areas of negative and two areas of positive power absorption. For the even higher discharge power (above 803.5 W), the number of areas is the same as that of the medium discharge power, but the size of the inner positive and negative power absorption areas is approximately doubled and halved, respectively, while the outer positive and negative power absorption areas slightly shrinks. The evolution of positive and negative power absorption regions is explained as a result of electron thermal diffusion and the energy conversion between rf current and electric field. The spatial decays of electric field and current density are also elucidated by linking them with the positive and negative power absorption pattern.

  9. Total absorption spectroscopy study of ?Rb decay: A major contributor to reactor antineutrino spectrum shape [Total absorption spectroscopy study of ?Rb: A major contributor to reactor antineutrino flux

    SciTech Connect (OSTI)

    Sonzogni, A.; Zakari-Issoufou, A. -A.; Fallot, M.; Porta, A.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Bui, V. M.; Cormon, S.; Estienne, M.; Agramunt, J.; Aysto, J.; Bowry, M.; Briz Monago, J. A.; Caballero-Folch, R.; Cano-Ott, D.; Cucoanes, A.; Eloma, V.; Estvez, E.; Farrelly, G. F.; Garcia, A.; Gelletly, W.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Kondev, F. G.; Martinez, T.; Mendoza, E.; Molina, F.; Moore, I.; Perez, A.; Podolyak, Zs.; Penttil, H.; Regan, P. H.; Shiba, T.; Rissanen, J.; Rubio, B.; Weber, C.

    2015-03-09

    The accurate determination of the emitted reactor antineutrino flux is still a major challenge for actual and future neutrino experiments at reactors, especially after the evidence of a disagreement between the measured antineutrino energy spectrum by Double Chooz, Daya Bay, and Reno and calculated antineutrino spectra obtained from the conversion of the unique integral beta spectra measured at the ILL reactor. Using nuclear data to compute reactor antineutrino spectra may help understanding this bias, with the study of the underlying nuclear physics. Summation calculations allow identifying a list of nuclei that contribute importantly to the antineutrino energy spectra emitted after the fission of ?,?Pu and ?,?U, and whose beta decay properties might deserve new measurements. Among these nuclei, ?Rb exhausts by itself about 16% of of the antineutrino energy spectrum emitted by Pressurized Water Reactors in the 5 to 8 MeV range. In this Letter, we report new Total Absorption Spectroscopy (TAS) results for this important contributor. The obtained beta feeding from ?Rb shows beta intensity unobserved before in the 4.5 to 5.5 MeV energy region and gives a ground state to ground state branch of 87.5 % 3%. These new data induce a dramatic change in recent summation calculations where a 51% GS to GS branch was considered for ?Rb, increasing the summation antineutrino spectrum in the region nearby the observed bias.The new data still have an important impact on other summation calculations in which more recent data were considered

  10. HELIUM IN NATAL H II REGIONS: THE ORIGIN OF THE X-RAY ABSORPTION IN GAMMA-RAY BURST AFTERGLOWS

    SciTech Connect (OSTI)

    Watson, Darach; Andersen, Anja C.; Fynbo, Johan P. U.; Hjorth, Jens; Kruehler, Thomas; Laursen, Peter; Leloudas, Giorgos; Malesani, Daniele [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Zafar, Tayyaba [Laboratoire d'Astrophysique de Marseille - LAM, Universite Aix-Marseille and CNRS, UMR 7326, 38 rue F. Joliot-Curie, F-13388, Marseille Cedex 13 (France); Gorosabel, Javier [Instituto de Astrofisica de Andalucia (IAA-CSIC), Glorieta de la Astronomia s/n, E-18008, Granada (Spain); Jakobsson, Pall, E-mail: darach@dark-cosmology.dk [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland)

    2013-05-01

    Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that absorption by He in the GRB's host H II region is responsible for most of the absorption. We show that the X-ray absorbing column density (N{sub H{sub X}}) is correlated with both the neutral gas column density and with the optical afterglow's dust extinction (A{sub V} ). This correlation explains the connection between dark bursts and bursts with high N{sub H{sub X}} values. From these correlations, we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e., the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this, we conclude that the column density of the X-ray absorption is correlated with the total gas column density in the host galaxy rather than the metal column density, in spite of the fact that X-ray absorption is typically dominated by metals. The strong redshift evolution of N{sub H{sub X}}/A{sub V} is thus a reflection of the cosmic metallicity evolution of star-forming galaxies and we find it to be consistent with measurements of the redshift evolution of metallicities for GRB host galaxies. We conclude that the absorption of X-rays in GRB afterglows is caused by He in the H II region hosting the GRB. While dust is destroyed and metals are stripped of all of their electrons by the GRB to great distances, the abundance of He saturates the He-ionizing UV continuum much closer to the GRB, allowing it to remain in the neutral or singly-ionized state. Helium X-ray absorption explains the correlation with total gas, the lack of strong evolution with redshift, as well

  11. Influence of plasma parameters on the absorption coefficient of alpha particles to lower hybrid waves in tokamaks

    SciTech Connect (OSTI)

    Wang, J.; Zhang, X. Yu, L.; Zhao, X.

    2014-12-15

    In tokamaks, fusion generated ? particles may absorb lower hybrid (LH) wave energy, thus reducing the LH current drive efficiency. The absorption coefficient ?{sub ?} of LH waves due to ? particles changing with some typical parameters is calculated in this paper. Results show that ?{sub ?} increases with the parallel refraction index n{sub ?}, while decreases with the frequency of LH waves ? over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption. The absorption coefficient ?{sub ?} increases with n{sub e} when n{sub e} ? 8 10{sup 19} m{sup ?3}, while decreases with n{sub e} when n{sub e} becomes larger, and there is a peak value of ?{sub ?} when n{sub e} ? 8 10{sup 19} m{sup ?1} for the ITER-like scenario. The influence of spectral broadening in parametric decay instabilities on the absorption coefficient is evaluated. The value of ?{sub ?} with n{sub ?} being 2.5 is almost two times larger than that with n{sub ?} being 2.0 and is even lager in the case of 2.9, which will obviously increase the absorption of the LH power by alpha particles.

  12. Method of analyzing multiple sample simultaneously by detecting absorption and systems for use in such a method

    DOE Patents [OSTI]

    Yeung, Edward S.; Gong, Xiaoyi

    2004-09-07

    The present invention provides a method of analyzing multiple samples simultaneously by absorption detection. The method comprises: (i) providing a planar array of multiple containers, each of which contains a sample comprising at least one absorbing species, (ii) irradiating the planar array of multiple containers with a light source and (iii) detecting absorption of light with a detetion means that is in line with the light source at a distance of at leaat about 10 times a cross-sectional distance of a container in the planar array of multiple containers. The absorption of light by a sample indicates the presence of an absorbing species in it. The method can further comprise: (iv) measuring the amount of absorption of light detected in (iii) indicating the amount of the absorbing species in the sample. Also provided by the present invention is a system for use in the abov metho.The system comprises; (i) a light source comrnpising or consisting essentially of at leaat one wavelength of light, the absorption of which is to be detected, (ii) a planar array of multiple containers, and (iii) a detection means that is in line with the light source and is positioned in line with and parallel to the planar array of multiple contiainers at a distance of at least about 10 times a cross-sectional distance of a container.

  13. Note: Sample chamber for in situ x-ray absorption spectroscopy studies of battery materials

    SciTech Connect (OSTI)

    Pelliccione, CJ; Timofeeva, EV; Katsoudas, JP; Segre, CU

    2014-12-01

    In situ x-ray absorption spectroscopy (XAS) provides element-specific characterization of both crystalline and amorphous phases and enables direct correlations between electrochemical performance and structural characteristics of cathode and anode materials. In situ XAS measurements are very demanding to the design of the experimental setup. We have developed a sample chamber that provides electrical connectivity and inert atmosphere for operating electrochemical cells and also accounts for x-ray interactions with the chamber and cell materials. The design of the sample chamber for in situ measurements is presented along with example XAS spectra from anode materials in operating pouch cells at the Zn and Sn K-edges measured in fluorescence and transmission modes, respectively. (C) 2014 AIP Publishing LLC.

  14. Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching

    SciTech Connect (OSTI)

    Sivarajah, I.; Goodman, D. S.; Wells, J. E.; Smith, W. W.; Narducci, F. A.

    2013-11-15

    Linear Paul traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions, and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field.

  15. Photon assisted processes: Probability amplitudes for the absorption and emission of photons and dc-photocurrents

    SciTech Connect (OSTI)

    Micu, C.; Racolta, D.; Papp, E.

    2014-11-24

    In this paper one deals with the derivation of probability amplitudes characterizing the photon assisted injection of electrons in a two-terminal quantum conductor. For this purpose one accounts for spatially constant but time dependent periodic voltages applied on an Ohmic contact. Resorting to the discrete Fourier transform provides the probability amplitudes for the emission and absorption of photons in terms of squared Bessel functions of the first kind and integer order. Several kinds of ac-pulses like sinusoidal and dc+sinusoidal are assumed. Mean square values concerning photon numbers have been discussed in some more detail. Time averages of squared time dependent classical currents and leading corrections to the rescaled dc-photocurrent have also been accounted for.

  16. Correcting for telluric absorption: Methods, case studies, and release of the TelFit code

    SciTech Connect (OSTI)

    Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah

    2014-09-01

    Ground-based astronomical spectra are contaminated by the Earth's atmosphere to varying degrees in all spectral regions. We present a Python code that can accurately fit a model to the telluric absorption spectrum present in astronomical data, with residuals of ∼3%-5% of the continuum for moderately strong lines. We demonstrate the quality of the correction by fitting the telluric spectrum in a nearly featureless A0V star, HIP 20264, as well as to a series of dwarf M star spectra near the 819 nm sodium doublet. We directly compare the results to an empirical telluric correction of HIP 20264 and find that our model-fitting procedure is at least as good and sometimes more accurate. The telluric correction code, which we make freely available to the astronomical community, can be used as a replacement for telluric standard star observations for many purposes.

  17. Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals, Final Technical Report

    DOE R&D Accomplishments [OSTI]

    Curl, Robert F.; Glass, Graham P.

    2004-11-01

    This research was directed at the detection, monitoring, and study of the chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. Work on the reaction of OH with acetaldehyde has been completed and published and work on the reaction of O({sup 1}D) with CH{sub 4} has been completed and submitted for publication. In the course of our investigation of branching ratios of the reactions of O({sup 1}D) with acetaldehyde and methane, we discovered that hot atom chemistry effects are not negligible at the gas pressures (13 Torr) initially used. Branching ratios of the reaction of O({sup 1}D) with CH{sub 4} have been measured at a tenfold higher He flow and fivefold higher pressure.

  18. LPG recovery from refinery flare by waste heat powered absorption refrigeration

    SciTech Connect (OSTI)

    Erickson, D.C.; Kelly, F.

    1998-07-01

    A waste heat powered ammonia Absorption Refrigeration Unit (ARU) has commenced operation at the Colorado Refining Company in Commerce City, Colorado. The ARU provides 85 tons of refrigeration at 30 F to refrigerate the net gas/treat gas stream, thereby recovering 65,000 barrels per year of LPG which formerly was flared or burned as fuel. The ARU is powered by the 290 F waste heat content of the reform reactor effluent. An additional 180 tons of refrigeration is available at the ARU to debottleneck the FCC plant wet gas compressors by cooling their inlet vapor. The ARU is directly integrated into the refinery processes, and uses enhanced, highly compact heat and mass exchange components. The refinery's investment will pay back in less than two years from increased recovery of salable product, and CO{sub 2} emissions are decreased by 10,000 tons per year in the Denver area.

  19. The Clean Coal Technology Program 100 MWe demonstration of gas suspension absorption for flue gas desulfurization

    SciTech Connect (OSTI)

    Hsu, F.E.; Hedenhag, J.G.; Marchant, S.K.; Pukanic, G.W.; Norwood, V.M.; Burnett, T.A.

    1997-12-31

    AirPol Inc., with the cooperation of the Tennessee Valley Authority (TVA) under a Cooperative Agreement with the United States Department of Energy, installed and tested a 10 MWe Gas Suspension Absorption (GSA) Demonstration system at TVA`s Shawnee Fossil Plant near Paducah, Kentucky. This low-cost retrofit project demonstrated that the GSA system can remove more than 90% of the sulfur dioxide from high-sulfur coal-fired flue gas, while achieving a relatively high utilization of reagent lime. This paper presents a detailed technical description of the Clean Coal Technology demonstration project. Test results and data analysis from the preliminary testing, factorial tests, air toxics texts, 28-day continuous demonstration run of GSA/electrostatic precipitator (ESP), and 14-day continuous demonstration run of GSA/pulse jet baghouse (PJBH) are also discussed within this paper.

  20. In Situ Diffuse Reflectance IR Spectroscopy and X-ray Absorption Spectroscopy for Fast Catalytic Processes

    SciTech Connect (OSTI)

    N Marinkovic; Q Wang; A Frenkel

    2011-12-31

    A new instrument for synchronous in situ investigations of catalytic materials by IR and X-ray absorption spectroscopies was designed and built at the X18A beamline of the National Synchrotron Light Source of Brookhaven National Laboratory. It provides analytical tools for solving structural, electronic and kinetic problems in catalysis science by two complementary methods. Among the features attractive for catalysis research are the broad range of catalytically active elements that can be investigated (starting with Ni and beyond), the wide range of reaction conditions (temperatures up to 873 K, various reactive gases) and time scales (starting from tens of seconds). The results of several representative experiments that illustrate the attractive capabilities of the new set-up are discussed.

  1. Investigation of the part-load performance of an absorption chiller

    SciTech Connect (OSTI)

    Radermacher, R.; Didion, D.A.; Klein, S.A.

    1983-01-01

    An experimental investigation designed to determine the part-load performance of an ammonia-water absorption water chiller is described. The steady-state and cyclic performance of the chiller were measured under controlled conditions in an environmental chamber. Two valves were installed in the chiller to separate high- and low-pressure regions during off times, and insulation was applied to the chiller components. By these measures, losses due to cyclic operation were reduced by over 50%, resulting in a 6% to 7% increase in the calculated seasonal performance factor for typical northern and southern climates in the United States. The use of the valves eliminated the need of the ''spindown'' period, thereby reducing the consumption of parasitic electrical energy.

  2. Two-photon Absorption In Quantum Dots,quantum Dashes And Related Materials

    SciTech Connect (OSTI)

    Jain, Ravinder

    2009-08-31

    We have proposed the use of USQDs for various deep-tissue biological imaging applications, notably wavelength-multiplexed multicolor imaging and intra-nuclear studies such as those involving cell apoptosis, and have studied the issue of maximizing two-photon absorption-induced fluorescence (TPAF) signals from CdSe/ZnS USQDs to be used for this application. In particular, using 2 nm USQDs, we have shown that the TPAF signal at 780 nm is ~ 8 times that at 850 nm and 68 times that at 900 nm, two wavelengths that have been used in previous studies using CdSe/ZnS SQDs for deep-tissue imaging of biological studies via TPAF .

  3. Performance predictions of alternative, low cost absorbents for open-cycle absorption solar cooling

    SciTech Connect (OSTI)

    Ameel, T.A.; Gee, K.G.; Wood, B.D.

    1995-02-01

    To achieve solar fractions greater than 0.90 using the open-cycle absorption refrigeration system, considerable sorbent solution storage is necessary. Having identified the absorber as the system component whose performance is affected the most by a change in absorbent, an absorber model was selected from available literature pertaining to simultaneous heat and mass transfer. Low-cost absorbent candidates were selected and their physical properties were either located in the literature, measured, or estimated. The most promising of the absorbents considered was a mixture of two parts lithium chloride and one part zinc chloride. Both the lithium-zinc chloride mixture and lithium bromide solutions had estimated pumping powers of less than 0.1 kW. The solubility of the lithium-zinc chloride mixture at absorber conditions was improved over that of lithium bromide, reducing the risk of solidification of the solution. 16 refs., 4 figs., 2 tabs.

  4. Elementary reaction rate measurements at high temperatures by tunable-laser flash-absorption

    SciTech Connect (OSTI)

    Hessler, J.P.

    1993-12-01

    The major objective of this program is to measure thermal rate coefficients and branching ratios of elementary reactions. To perform these measurements, the authors constructed an ultrahigh-purity shock tube to generate temperatures between 1000 and 5500 K. The tunable-laser flash-absorption technique is used to measure the rate of change of the concentration of species which absorb below 50,000 cm{sup {minus}1} e.g.: OH, CH, and CH{sub 3}. This technique is being extended into the vacuum-ultraviolet spectral region where one can measure atomic species e.g.: H, D, C, O, and N; and diatomic species e.g.: O{sub 2}, CO, and OH.

  5. Ultraviolet Absorption Spectrum of Malonaldehyde in Water Is Dominated by Solvent-Stabilized Conformations

    SciTech Connect (OSTI)

    Xu, Xuefei; Zheng, Jingjing; Truhlar, Donald G.

    2015-07-01

    Free energy calculations for eight enol isomers of malonaldehyde (MA) and simulation of the ultraviolet (UV) absorption spectrum in both the gas phase and water (pH = 3, where the molecule exists in neutral undeprotonated form) show that in water the two s-trans nonchelated enol conformers of MA become thermodynamically more stable than the internally hydrogen-bonded (“chelated enol”) conformer (CE). The pure CE conformer in water has a slightly red-shifted UV spectrum with respect to that in the gas phase, but the blue-shifted spectrum observed in water at pH 3 is dominated by solvent-stabilized conformations that have negligible populations in the gas phase. Density functional calculations with the solvation model based on density (SMD) and an ensemble-averaged vertical excitation model explain the experimental observations in detail.

  6. Multiband Optical Absorption Controlled by Lattice Strain in Thin-Film LaCrO3

    SciTech Connect (OSTI)

    Sushko, Peter; Qiao, Liang; Bowden, Mark E.; Varga, Tamas; Exarhos, Gregory J.; Urban, III, Frank K.; Barton, David; Chambers, Scott A.

    2013-02-11

    Experimental measurements and ab initio modeling of the optical transitions in strained G-type antiferromagnetic LaCrO3 resolve two decades of debate regarding the magnitude of the optical band gap and the character of the corresponding transitions in this material. Using time-dependent density functional theory and accounting for thermal disorder effects, we demonstrate that the fourmost prominent low-energy absorption features are due to intra-Cr t2g {eg (2.4, 3.6 eV), inter-Crt2g {t2g (4.4 eV), and inter-ion O 2p { Cr 3d (from ?5 eV) transitions and show that the excitation energies of the latter type can be strongly affected by the lattice strain.

  7. Etalon-induced baseline drift and correction in atom flux sensors based on atomic absorption spectroscopy

    SciTech Connect (OSTI)

    Du, Yingge; Chambers, Scott A.

    2014-10-20

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific real-time flux sensing and control. The ultimate sensitivity and performance of these sensors are strongly affected by baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability, which has not been previously considered, and cannot be corrected using existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5% which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.

  8. Etalon-induced Baseline Drift And Correction In Atom Flux Sensors Based On Atomic Absorption Spectroscopy

    SciTech Connect (OSTI)

    Du, Yingge; Chambers, Scott A.

    2014-10-20

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific, real-time flux sensing and control. The ultimate sensitivity and performance of the sensors are strongly affected by the long-term and short term baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability which has not been previously considered or corrected by existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5%, which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.

  9. Auto-oligomerization and hydration of pyrrole revealed by x-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Advanced Light Source; Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; England, Alice H.; Prendergast, David; Saykally, Richard J

    2009-05-29

    Near edge x-ray absorption fine structure (NEXAFS) spectra have been measured at the carbon and nitrogen K-edges of the prototypical aromatic molecule, pyrrole, both in the gas phase and when solvated in water, and compared with spectra simulated using a combination of classical molecular dynamics and first principles density functional theory in the excited state core hole approximation. The excellent agreement enabled detailed assignments. Pyrrole is highly reactive, particularly in water, and reaction products formed by the auto-oligomerization of pyrrole are identified. The solvated spectra have been measured at two different temperatures, indicating that the final states remain largely unaffected by both hydration and temperature. This is somewhat unexpected, since the nitrogen in pyrrole can donate a hydrogen bond to water.

  10. Simulation of spray drying with reaction: Absorption of hydrogen sulfide in ammoniacal solution of zinc chloride

    SciTech Connect (OSTI)

    Chander, H.; Ghosh, P.K. ); Baveja, K.K.; Dhingra, S.C. )

    1993-01-01

    Absorption of hydrogen sulfide gas in ammoniacal solution of zinc chloride is accompanied with an instantaneous chemical reaction forming zinc sulfide precipitates. Such reactions are most suited for operation of spray drying with reaction. A mathematical model for the system which incorporates chemical reaction, heat, mass and momentum transfer has been proposed. It is assumed that the gases and the spray is considered monodisperse for sake of simplicity. The differential equations derived for the model have been solved as an initial value problem using the Runge-Kutta method. The variations of temperature, humidity, droplet diameter, moisture content and concentrations of reactants are predicted along the length of the column and compared with experimental data.

  11. ISMabs: A COMPREHENSIVE X-RAY ABSORPTION MODEL FOR THE INTERSTELLAR MEDIUM

    SciTech Connect (OSTI)

    Gatuzz, E.; Mendoza, C.; García, J.; Kallman, T. R.; Gorczyca, T. W. E-mail: claudio@ivic.gob.ve E-mail: timothy.r.kallman@nasa.gov

    2015-02-10

    We present an X-ray absorption model for the interstellar medium, to be referred to as ISMabs, that takes into account both neutral and ionized species of cosmically abundant elements, and includes the most accurate atomic data available. Using high-resolution spectra from eight X-ray binaries obtained with the Chandra High Energy Transmission Grating Spectrometer, we proceed to benchmark the atomic data in the model particularly in the neon K-edge region. Compared with previous photoabsorption models, which solely rely on neutral species, the inclusion of ions leads to improved spectral fits. Fit parameters comprise the column densities of abundant contributors that allow direct estimates of the ionization states. ISMabs is provided in the appropriate format to be implemented in widely used X-ray spectral fitting packages such as XSPEC, ISIS, and SHERPA.

  12. X-ray Absorption Spectroscopy Beamline at the Siam Photon Laboratory

    SciTech Connect (OSTI)

    Klysubun, Wantana; Tarawarakarn, Pongjakr; Sombunchoo, Panidtha; Klinkhieo, Supat; Chaiprapa, Jitrin; Songsiriritthigul, Prayoon

    2007-01-19

    A bending magnet beamline has been constructed and commissioned for x-ray absorption spectroscopy (XAS) at the Siam Photon Laboratory. The photon energy is tunable from 1830 eV to 8000 eV using a Lemmonier-type, fixed-exit double crystal monochromator equipped with InSb(111), Si(111), Ge(220) crystals. Elemental K-edges are then accessible from silicon to iron. A series of low conductance vacuum tubes has been designed and installed between the pumping chambers in the front end to obtain the proper pressure difference between the upstream and the downstream of the front end. Thus lower-energy photons, around K-edges of silicon, phosphorous, and sulfur, can be delivered to the experimental XAS station without being absorbed by a window. In this report, the design of the beamline is described. The commissioning results including the measured photon flux at sample and experimental XAS spectra are presented.

  13. Hydrogen absorption characteristics of amorphous LaNi[sub 5. 0] films prepared by reactive sputtering

    SciTech Connect (OSTI)

    Sakaguchi, H.; Tsujimoto, T.; Adachi, Ginya (Osaka University, Suita (Japan))

    1993-01-01

    Amorphous LaNi[sub 5] thin films are expected to be one of the promising materials for use in hydrogen separation and battery electrodes, because the durability of the films is great in regard to the hydrogen absorption-desorption cycling process and the films have excellent resistance to harmful impurities in the hydrogen gas in comparison with the crystalline bulk material. An amorphous LaNi[sub 5.0] film having high hydrogen density and low hydrogen-induced stress was obtained by means of a reactive sputtering method using an Ar-H[sub 2] gas mixture. Pressure-composition isotherms show that the amount of hydrogen (H/LaNi[sub 5.0]) taken up by a formula weight of LaNi[sub 5.0] is about 1.5 times larger for the reactive sputtered film than for the conventional sputtered film prepared by using Ar gas. 18 refs., 1 fig, 1 tabs.

  14. Multi-phonon-assisted absorption and emission in semiconductors and its potential for laser refrigeration

    SciTech Connect (OSTI)

    Khurgin, Jacob B.

    2014-06-02

    Laser cooling of semiconductors has been an elusive goal for many years, and while attempts to cool the narrow gap semiconductors such as GaAs are yet to succeed, recently, net cooling has been attained in a wider gap CdS. This raises the question of whether wider gap semiconductors with higher phonon energies and stronger electron-phonon coupling are better suitable for laser cooling. In this work, we develop a straightforward theory of phonon-assisted absorption and photoluminescence of semiconductors that involves more than one phonon and use to examine wide gap materials, such as GaN and CdS and compare them with GaAs. The results indicate that while strong electron-phonon coupling in both GaN and CdS definitely improves the prospects of laser cooling, large phonon energy in GaN may be a limitation, which makes CdS a better prospect for laser cooling.

  15. Resonant formation of {Lambda}(1405) by stopped-K{sup -} absorption in the deuteron

    SciTech Connect (OSTI)

    Esmaili, Jafar; Akaishi, Yoshinori; Yamazaki, Toshimitsu

    2011-05-15

    To solve the current debate on the position of the quasibound K{sup -}p state, namely, ''{Lambda}(1405) or {Lambda}*(1420),'' we propose to measure the T{sub 21}=T{sub {Sigma}{pi}<-K}-bar{sub N} {Sigma}{pi} invariant-mass spectrum in stopped-K{sup -} absorption in the deuteron, since the spectrum, reflecting the soft and hard deuteron momentum distribution, is expected to have a narrow quasifree component with an upper edge of M=1430 MeV/c{sup 2}, followed by a significant 'high-momentum' tail toward the lower mass region, where a resonant formation of {Lambda}(1405) of any mass and width in a wide range will be clearly revealed. We introduce a 'deviation' spectrum as defined by DEV = OBS (observed or calculated) / QF (nonresonant quasifree), in which the resonant component can be seen as an isolated peak free from the QF shape.

  16. APPLICATION OF POLYURETHANE FOAM FOR IMPACT ABSORPTION AND THERMAL INSULATION FOR GENERAL PURPOSE RADIOACTIVE MATERIALS PACKAGINGS

    SciTech Connect (OSTI)

    Smith, A; Glenn Abramczyk, G; Paul Blanton, P; Steve Bellamy, S; William Daugherty, W; Sharon Williamson, S

    2009-02-18

    Polyurethane foam has been employed in impact limiters for large radioactive materials packagings since the early 1980's. Its consistent crush response, controllable structural properties and excellent thermal insulating characteristics have made it attractive as replacement for the widely used cane fiberboard for smaller, drum size packagings. Accordingly, polyurethane foam was chosen for the overpack material for the 9977 and 9978 packagings. The study reported here was undertaken to provide data to support the analyses performed as part of the development of the 9977 and 9978, and compared property values reported in the literature with published property values and test results for foam specimens taken from a prototype 9977 packaging. The study confirmed that, polyurethane foam behaves in a predictable and consistent manner and fully satisfies the functional requirements for impact absorption and thermal insulation.

  17. Further developments of capillary absorption spectrometers using small hollow-waveguide fibers

    SciTech Connect (OSTI)

    Kelly, James F.; Sams, Robert L.; Blake, Thomas A.; Kriesel, Jason M.

    2014-05-01

    Our objective is to enhance quantification of stable carbon and oxygen isotope ratios to better than 1 relative isotope precision for sample sizes < 1 pico-mole. A newer variant Capillary Absorption Spectrometer (CAS) is described using a proprietary linear-taper hollow waveguide in conjunction with wavelength and frequency modulation techniques of tunable laser absorption spectrometry. Previous work used circular capillaries with uniform 1 mm ID to measure 13C/12C ratios with ? 20 pico-mole samples to ? 10 ppm (1 precision against standards) [1]. While performing fairly well, it generated residual modal noise due to multipath propagation in the hollow-waveguides (HWGs). This system has been utilized with laser ablation-catalytic combustion techniques to analyze small resolution (~ 25 ?m spot diameter) laser ablation events on solids. Using smaller ID capillary waveguides could improve detection limits and spatial resolutions. Reducing an IR compatible hollow waveguides inner diameter (ID) to < 300 ?m, reduces modal noise significantly for mid-IR operation, but feedback noise with high gain semiconductor lasers can become problematic. A proprietary linear-taper small waveguide (mean ID = 0.35 mm, L = 1 m) was tested to understand whether modal noise and optical feedback effects could be simultaneously reduced. We see better mode filtering and, significant reductions of feedback noise under favorable coupling of a multi-spatial mode QC laser to the smaller ID of the linear-tapered HWG. We demonstrate that better modal coupling operation is consistent with Liouvilles theorem, where greater suppression of feedback from spurious scatter within the HWG occurs by injecting the laser into the smaller ID port. Our progress on developing lighter weight, potentially fieldable alternatives to Isotope Ratio Mass Spectrometers (IRMS) with a small volume (? 0.1 cm3) CAS system will be discussed and compared to other competitive systems.

  18. Americium characterization by X-ray fluorescence and absorption spectroscopy in plutonium uranium mixed oxide

    SciTech Connect (OSTI)

    Degueldre, Claude Cozzo, Cedric; Martin, Matthias; Grolimund, Daniel; Mieszczynski, Cyprian

    2013-06-01

    Plutonium uranium mixed oxide (MOX) fuels are currently used in nuclear reactors. The actinides in these fuels need to be analyzed after irradiation for assessing their behaviour with regard to their environment and the coolant. In this work the study of the atomic structure and next-neighbour environment of Am in the (Pu,U)O? lattice in an irradiated (60 MW d kg?) MOX sample was performed employing micro-X-ray fluorescence (-XRF) and micro-X-ray absorption fine structure (-XAFS) spectroscopy. The chemical bonds, valences and stoichiometry of Am (~0.66 wt%) are determined from the experimental data gained for the irradiated fuel material examined in its peripheral zone (rim) of the fuel. In the irradiated sample Am builds up as Am? species within an [AmO?]? coordination environment (e.g. >90%) and no (<10%) Am(IV) or (V) can be detected in the rim zone. The occurrence of americium dioxide is avoided by the redox buffering activity of the uranium dioxide matrix. - Graphical abstract: Americium LIII XAFS spectra recorded for the irradiated MOX sub-sample in the rim zone for a 300 ?m300 ?m beam size area investigated over six scans of 4 h. The records remain constant during multi-scan. The analysis of the XAFS signal shows that Am is found as trivalent in the UO? matrix. This analytical work shall open the door of very challenging analysis (speciation of fission product and actinides) in irradiated nuclear fuels. - Highlights: Americium was characterized by microX-ray absorption spectroscopy in irradiated MOX fuel. The americium redox state as determined from XAS data of irradiated fuel material was Am(III). In the sample, the Am? face an AmO??coordination environment in the (Pu,U)O? matrix. The americium dioxide is reduced by the uranium dioxide matrix.

  19. Carbonic anhydrase-facilitated CO2 absorption with polyacrylamide buffering bead capture

    SciTech Connect (OSTI)

    Dilmore, Robert; Griffith, Craid; Liu, Zhu; Soong, Yee; Hedges, Sheila W.; Koepsel, Richard; Ataai, M [Ataai, Mohammad

    2009-07-01

    A novel CO2 separation concept is described wherein the enzyme carbonic anhydrase (CA) is used to increase the overall rate Of CO2 absorption after which hydrated CO2 reacts with regenerable amine-bearing polyacrylamide buffering beads (PABB). Following saturation of the material's immobilized tertiary amines, CA-bearing carrier water is separated and recycled to the absorption stage while CO2-loaded material is thermally regenerated. Process application of this concept would involve operation of two or more columns in parallel with thermal regeneration with low-pressure steam taking place after the capacity of a column of amine-bearing polymeric material was exceeded. PABB CO2- bearing capacity was evaluated by thermogravimetric analysis (TGA) for beads of three acrylamido buffering monomer ingredient concentrations: 0 mol/kg bead, 0.857 mol/kg bead, and 2 mol/kg bead. TGA results demonstrate that CO2- bearing capacity increases with increasing PABB buffering concentration and that up to 78% of the theoretical CO2- bearing capacity was realized in prepared PABB samples (0.857 mol/kg recipe). The highest observed CO2-bearing capacity of PABB was 1.37 mol of CO2 per kg dry bead. TGA was also used to assess the regenerability Of CO2-loaded PABB. Preliminary results suggest that CO2 is partially driven from PABB samples at temperatures as low as 55 degrees C, with complete regeneration occurring at 100 degrees C. Other physical characteristics of PABB are discussed. In addition, the effectiveness of bovine carbonic anhydrase for the catalysis Of CO2 dissolution is evaluated. Potential benefits and drawbacks of the proposed process are discussed. Published by Elsevier Ltd.

  20. Collisional absorption of laser light in under-dense plasma: The role of Coulomb logarithm

    SciTech Connect (OSTI)

    Kundu, M. [Institute for Plasma Research, Bhat, Gandhinagar 382 428, Gujarat (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382 428, Gujarat (India)

    2014-01-15

    In this work, we re-examine collisional absorption of 800?nm wavelength laser pulses in under-dense plasma. For a given temperature and density of the plasma, most of the conventional models of the electron-ion collision frequency ?{sub ei}, with a Coulomb logarithm independent of the electron-ponderomotive velocity, show that ?{sub ei} and the corresponding fractional laser absorption ? remain almost constant (or decrease slowly) up to a value I{sub c} of the peak intensity I{sub 0} of the laser pulse, and then ?{sub ei} and ? decrease as ?I{sub 0}{sup ?3/2} when I{sub 0} is increased beyond I{sub c}. On the contrary, below some temperature (?10?eV) and density, with a total-velocity (thermal velocity plus the ponderomotive velocity) dependent Coulomb logarithm, we find that ?{sub ei} and ? grow hand in hand up to a maximum value around I{sub c} followed by the conventional I{sub 0}{sup ?3/2} decrease when I{sub 0}>I{sub c}. Such a non-conventional anomalous variation of ? with I{sub 0} was observed in some earlier experiments, but no explanation has been given so far. The modified Coulomb logarithm considered in this work may be responsible for those experimental observations. With increasing temperature and density, the anomalous behavior is found to disappear even with the modified Coulomb logarithm, and the variation of ?{sub ei} and ? with I{sub 0} approach to the conventional scenario.

  1. Magnetic circular dichroism in x-ray absorption and core-level photoemission

    SciTech Connect (OSTI)

    Tobin, J.G.; Waddill, G.D.; Gouder, T.H.; Colmenares, C.A.; Pappas, D.P.

    1993-03-17

    Here is reported observation of magnetic circular dichroism in both x-ray absorption and core-level photoemission of ultra thin magnetic films using circularly polarized x-rays. Iron films (1--4 ML) grown on a Cu(001) substrate at 150 K and magnetized perpendicular to the surface show dramatic changes in the L{sub 2,3} branching ratio for different x-ray polarizations. For linearly-polarized x-rays perpendicular to the magnetic axis of the sample the branching ratio was 0.75. For films {ge} 2 ML, this ratio varied from 0.64 to 0.85 for photon spin parallel and anti-parallel, respectively, to the magnetic axis. This effect was observed either by changing the x-ray helicity for a fixed magnetic axis, or by reversing the magnetic axis for a fixed x-ray helicity. Our observation can be analyzed within a simple one-electron picture, if the raw branching ratios are no so that the linear value becomes statistical Furthermore, warming the films to {approximately}300 K eliminated this effect, indicating a loss of magnetization in the film over a temperature range of {approximately}30 K. Finally, reversing the relative orientation of the photon spin and the magnetic axis from parallel to anti-parallel allowed measurement of the exchange splitting of the Fe 2p and 3p core levels which were found to be 0.3 eV and 0.2 eV. respectively. These results are consistent with earlier studies, but the use of off-plane circularly-polarized x-rays from a bending magnet monochromator offers {approximately}2 orders of magnitude greater intensity than typical spin-polarization measurements. Finally, we have performed preliminary x-ray absorption studies of UFe{sub 2}, demonstrating the feasibilty of MCD measurements in 5f as well as 3d materials.

  2. Optical absorption in epitaxial La{sub 1-x}Sr{sub x}FeO{sub 3} thin films

    SciTech Connect (OSTI)

    Scafetta, M D.; Xie, Y. J.; Torres, M.; Spanier, J. E.; May, S. J.

    2013-02-25

    We report the dependence of optical absorption on Sr concentration in La{sub 1-x}Sr{sub x}FeO{sub 3} (LSFO) (x{<=}0.4) perovskite thin films. Strained epitaxial films were deposited on SrTiO{sub 3} substrates using oxide molecular beam epitaxy. We find systematic changes in the optical absorption spectra with increasing x including a red-shift of transition energies and the increasing presence of a lower energy transition within the fundamental gap of pure LaFeO{sub 3}. These results serve as a demonstration of the complex manner in which absorption spectra can be altered in complex oxides via heterovalent A-site substitution.

  3. Resonant absorption in semiconductor nanowires and nanowire arrays: Relating leaky waveguide modes to Bloch photonic crystal modes

    SciTech Connect (OSTI)

    Fountaine, Katherine T.; Whitney, William S.; Atwater, Harry A.

    2014-10-21

    We present a unified framework for resonant absorption in periodic arrays of high index semiconductor nanowires that combines a leaky waveguide theory perspective and that of photonic crystals supporting Bloch modes, as array density transitions from sparse to dense. Full dispersion relations are calculated for each mode at varying illumination angles using the eigenvalue equation for leaky waveguide modes of an infinite dielectric cylinder. The dispersion relations along with symmetry arguments explain the selectivity of mode excitation and spectral red-shifting of absorption for illumination parallel to the nanowire axis in comparison to perpendicular illumination. Analysis of photonic crystal band dispersion for varying array density illustrates that the modes responsible for resonant nanowire absorption emerge from the leaky waveguide modes.

  4. A doubly curved elliptical crystal spectrometer for the study of localized x-ray absorption in hot plasmas

    SciTech Connect (OSTI)

    Cahill, Adam D. Hoyt, Cad L.; Pikuz, Sergei A.; Shelkovenko, Tania; Hammer, David A.

    2014-10-15

    X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emitted by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here the foundational work in the design and development of this spectrometer along with initial results obtained with an aluminum x-pinch as the object plasma.

  5. X-ray absorption spectroscopy of aluminum z-pinch plasma with tungsten backlighter planar wire array source

    SciTech Connect (OSTI)

    Osborne, G. C.; Kantsyrev, V. L.; Safronova, A. S.; Esaulov, A. A.; Weller, M. E.; Shrestha, I.; Shlyaptseva, V. V.; Ouart, N. D.

    2012-10-15

    Absorption features from K-shell aluminum z-pinch plasmas have recently been studied on Zebra, the 1.7 MA pulse power generator at the Nevada Terawatt Facility. In particular, tungsten plasma has been used as a semi-backlighter source in the generation of aluminum K-shell absorption spectra by placing a single Al wire at or near the end of a single planar W array. All spectroscopic experimental results were recorded using a time-integrated, spatially resolved convex potassium hydrogen phthalate (KAP) crystal spectrometer. Other diagnostics used to study these plasmas included x-ray detectors, optical imaging, laser shadowgraphy, and time-gated and time-integrated x-ray pinhole imagers. Through comparisons with previous publications, Al K-shell absorption lines are shown to be from much lower electron temperature ({approx}10-40 eV) plasmas than emission spectra ({approx}350-500 eV).

  6. Hybrid Membrane/Absorption Process for Post-combustion CO2 Capture

    SciTech Connect (OSTI)

    Li, Shiguang; Shou, S.; Pyrzynski, Travis; Makkuni, Ajay; Meyer, Howard

    2013-12-31

    This report summarizes scientific/technical progress made for bench-scale membrane contactor technology for post-combustion CO2 capture from DOE Contract No. DE-FE-0004787. Budget Period 1 (BP1) membrane absorber, Budget Period 2 (BP2) membrane desorber and Budget Period 3 (BP3) integrated system and field testing studies have been completed successfully and met or exceeded the technical targets (≥ 90% CO2 removal and CO2 purity of 97% in one membrane stage). Significant breakthroughs are summarized below: BP1 research: The feasibility of utilizing the poly (ether ether ketone), PEEK, based hollow fiber contractor (HFC) in combination with chemical solvents to separate and capture at least 90% of the CO2 from simulated flue gases has been successfully established. Excellent progress has been made as we have achieved the BP1 goal: ≥ 1,000 membrane intrinsic CO2 permeance, ≥ 90% CO2 removal in one stage, ≤ 2 psi gas side pressure drop, and ≥ 1 (sec)-1 mass transfer coefficient. Initial test results also show that the CO2 capture performance, using activated Methyl Diethanol Amine (aMDEA) solvent, was not affected by flue gas contaminants O2 (~3%), NO2 (66 ppmv), and SO2 (145 ppmv). BP2 research: The feasibility of utilizing the PEEK HFC for CO2-loaded solvent regeneration has been successfully established High CO2 stripping flux, one order of magnitude higher than CO2 absorption flux, have been achieved. Refined economic evaluation based on BP1 membrane absorber and BP2 membrane desorber laboratory test data indicate that the CO2 capture costs are 36% lower than DOE’s benchmark amine absorption technology. BP3 research: A bench-scale system utilizing a membrane absorber and desorber was integrated into a continuous CO2 capture process using contactors containing 10 to 20 ft2 of membrane area. The integrated process operation was stable through a 100-hour laboratory test, utilizing a simulated flue gas stream. Greater than 90% CO2 capture combined with 97

  7. Infrared Absorption Spectroscopy and Chemical Kinetics of Free Radicals. Final Performance Report, August 1, 1985--July 31, 1994

    DOE R&D Accomplishments [OSTI]

    Curl, R. F.; Glass, G. P.

    1995-06-01

    This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis of the infrared spectrum of combustion radical to the utilization of the infrared spectrum thus obtained in the investigation of chemical kinetics of the radical species. The methodology employed was infrared kinetic spectroscopy. In this technique the radical is produced by UV flash photolysis using an excimer laser and then its transient infrared absorption is observed using a single frequency cw laser as the source of the infrared probe light. When the probe laser frequency is near the center of an absorption line of the radical produced by the flash, the transient infrared absorption rises rapidly and then decays as the radical reacts with the precursor or with substances introduced for the purpose of studying the reaction kinetics or with itself. The decay times observed in these studies varied from less than one microsecond to more than one millisecond. By choosing appropriate time windows after the flash and the average infrared detector signal in a window as data channels, the infrared spectrum of the radical may be obtained. By locking the infrared probe laser to the center of the absorption line and measuring the rate of decay of the transient infrared absorption signal as the chemical composition of the gas mixture is varied, the chemical kinetics of the radical may be investigated. In what follows the systems investigated and the results obtained are outlined.

  8. Stochastic Parameterization for Light Absorption by Internally Mixed BC/dust in Snow Grains for Application to Climate Models

    SciTech Connect (OSTI)

    Liou, K. N.; Takano, Y.; He, Cenlin; Yang, P.; Leung, Lai-Yung R.; Gu, Y.; Lee, W- L.

    2014-06-27

    A stochastic approach to model the positions of BC/dust internally mixed with two snow-grain types has been developed, including hexagonal plate/column (convex) and Koch snowflake (concave). Subsequently, light absorption and scattering analysis can be followed by means of an improved geometric-optics approach coupled with Monte Carlo photon tracing to determine their single-scattering properties. For a given shape (plate, Koch snowflake, spheroid, or sphere), internal mixing absorbs more light than external mixing. The snow-grain shape effect on absorption is relatively small, but its effect on the asymmetry factor is substantial. Due to a greater probability of intercepting photons, multiple inclusions of BC/dust exhibit a larger absorption than an equal-volume single inclusion. The spectral absorption (0.2 5 um) for snow grains internally mixed with BC/dust is confined to wavelengths shorter than about 1.4 um, beyond which ice absorption predominates. Based on the single-scattering properties determined from stochastic and light absorption parameterizations and using the adding/doubling method for spectral radiative transfer, we find that internal mixing reduces snow albedo more than external mixing and that the snow-grain shape plays a critical role in snow albedo calculations through the asymmetry factor. Also, snow albedo reduces more in the case of multiple inclusion of BC/dust compared to that of an equal-volume single sphere. For application to land/snow models, we propose a two-layer spectral snow parameterization containing contaminated fresh snow on top of old snow for investigating and understanding the climatic impact of multiple BC/dust internal mixing associated with snow grain metamorphism, particularly over mountains/snow topography.

  9. High-speed laser-induced fluorescence and spark plug absorption sensor diagnostics for mixing and combustion studies in engines

    SciTech Connect (OSTI)

    Cundy, Michael; Schucht, Torsten; Thiele, Olaf; Sick, Volker

    2009-02-01

    Simultaneous high-speed in-cylinder measurements of laser-induced fluorescence of biacetyl as a fuel tracer and mid-infrared broadband absorption of fuel and combustion products (water and carbon dioxide) using a spark plug probe are compared in an optical engine. The study addresses uncertainties and the applicability of absorption measurements at a location slightly offset to the spark plug when information about mixing at the spark plug is desired. Absorbance profiles reflect important engine operation events, such as valve opening and closing, mixing, combustion, and outgassing from crevices.

  10. Phase-dependent high refractive index without absorption in a four-level inverted-Y atomic system

    SciTech Connect (OSTI)

    Zhi-Qiang Zeng; Fu-Ti Liu; Yu-Ping Wang; Zeng-Hui Gao

    2015-01-31

    We consider a closed four-level inverted-Y system in the presence and the absence of a microwave field. It is found that due to the quantum coherence between the two lower levels, either induced by the spontaneous decay or by the microwave field, the refraction – absorption properties of the system can be modulated by controlling the relative phase of the applied fields in both driven ways. In particular, by properly setting the values of the relative phase, the desirable high index of refraction without absorption can be achieved. (nonlinear optical phenomena)

  11. Aerosol Observing System (AOS) Handbook

    SciTech Connect (OSTI)

    Jefferson, A

    2011-01-17

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earths radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  12. Femtosecond all-optical parallel logic gates based on tunable saturable to reverse saturable absorption in graphene-oxide thin films

    SciTech Connect (OSTI)

    Roy, Sukhdev Yadav, Chandresh

    2013-12-09

    A detailed theoretical analysis of ultrafast transition from saturable absorption (SA) to reverse saturable absorption (RSA) has been presented in graphene-oxide thin films with femtosecond laser pulses at 800 nm. Increase in pulse intensity leads to switching from SA to RSA with increased contrast due to two-photon absorption induced excited-state absorption. Theoretical results are in good agreement with reported experimental results. Interestingly, it is also shown that increase in concentration results in RSA to SA transition. The switching has been optimized to design parallel all-optical femtosecond NOT, AND, OR, XOR, and the universal NAND and NOR logic gates.

  13. Strain-optic voltage monitor wherein strain causes a change in the optical absorption of a crystalline material

    DOE Patents [OSTI]

    Weiss, J.D.

    1997-01-14

    A voltage monitor which uses the shift in absorption edge of crystalline material to measure strain resulting from electric field-induced deformation of piezoelectric or electrostrictive material, providing a simple and accurate means for measuring voltage applied either by direct contact with the crystalline material or by subjecting the material to an electric field. 6 figs.

  14. Characteristics and Performance of the Sunna High Dose Dosemeter Using Green Photoluminescence and UV Absorption Readout Methods

    SciTech Connect (OSTI)

    Miller, Steven D.; Murphy, Mark K.; Tinker, Mike R.; Kovacs, Andres; Mclaughlin, William

    2002-01-01

    Growth in the use of ionizing radiation for medical sterilization and the potential for wide-scale international food irradiation have created the need for robust, mass-producible, inexpensive, and highly accurate radiation dosemeters. The Sunna dosemeter, lithium fluoride injection-moulded in a polyethylene matrix, can be read out using either green photoluminescence or ultraviolet (UV) absorption.

  15. Signatures of a conical intersection in photofragment distributions and absorption spectra: Photodissociation in the Hartley band of ozone

    SciTech Connect (OSTI)

    Picconi, David; Grebenshchikov, Sergy Yu.

    2014-08-21

    Photodissociation of ozone in the near UV is studied quantum mechanically in two excited electronic states coupled at a conical intersection located outside the Franck-Condon zone. The calculations, performed using recent ab initio PESs, provide an accurate description of the photodissociation dynamics across the Hartley/Huggins absorption bands. The observed photofragment distributions are reproduced in the two electronic dissociation channels. The room temperature absorption spectrum, constructed as a Boltzmann average of many absorption spectra of rotationally excited parent ozone, agrees with experiment in terms of widths and intensities of diffuse structures. The exit channel conical intersection contributes to the coherent broadening of the absorption spectrum and directly affects the product vibrational and translational distributions. The photon energy dependences of these distributions are strikingly different for fragments created along the adiabatic and the diabatic paths through the intersection. They can be used to reverse engineer the most probable geometry of the non-adiabatic transition. The angular distributions, quantified in terms of the anisotropy parameter β, are substantially different in the two channels due to a strong anticorrelation between β and the rotational angular momentum of the fragment O{sub 2}.

  16. TESTING GRAVITATIONAL LENSING AS THE SOURCE OF ENHANCED STRONG Mg II ABSORPTION TOWARD GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Rapoport, Sharon; Onken, Christopher A.; Schmidt, Brian P.; Tucker, Brad E.; Wyithe, J. Stuart B.; Levan, Andrew J.

    2012-08-01

    Sixty percent of gamma-ray bursts (GRBs) reveal strong Mg II absorbing systems, which is a factor of {approx}2 times the rate seen along lines of sight to quasars. Previous studies argue that the discrepancy in the strong Mg II covering factor is most likely to be the result of either quasars being obscured due to dust or the consequence of many GRBs being strongly gravitationally lensed. We analyze observations of quasars that show strong foreground Mg II absorption. We find that GRB lines of sight pass closer to bright galaxies than would be expected for random lines of sight within the impact parameter expected for strong Mg II absorption. While this cannot be explained by obscuration in the GRB sample, it is a natural consequence of gravitational lensing. Upon examining the particular configurations of galaxies near a sample of GRBs with strong Mg II absorption, we find several intriguing lensing candidates. Our results suggest that lensing provides a viable contribution to the observed enhancement of strong Mg II absorption along lines of sight to GRBs, and we outline the future observations required to test this hypothesis conclusively.

  17. Recording of absorption spectra by a three-beam integral technique with a tunable laser and external cavity

    SciTech Connect (OSTI)

    Korolenko, P V; Nikolaev, I V; Ochkin, V N; Tskhai, S N

    2014-04-28

    An integral method is considered for recording absorption using three laser beams transmitted through and reflected from an external cavity with the absorbing medium (R-ICOS). The method is the elaboration of a known single-beam ICOS method and allows suppression of the influence of radiation phase fluctuations in the resonator on recording weak absorption spectra. First of all, this reduces high-frequency instabilities and gives a possibility to record spectra during short time intervals. In this method, mirrors of the resonator may have moderate reflection coefficients. Capabilities of the method have been demonstrated by the examples of weak absorption spectra of atmospheric methane and natural gas in a spectral range around 1650 nm. With the mirrors having the reflection coefficients of 0.80.99, a spectrum can be recorded for 320 ?s with the accuracy sufficient for detecting a background concentration of methane in atmosphere. For the acquisition time of 20 s, the absorption coefficients of ?210{sup -8} cm{sup -1} can be measured, which corresponds to a 40 times less molecule concentration than the background value. (laser spectroscopy)

  18. A theoretical analysis of the optical absorption properties in one-dimensional InAs/GaAs quantum dot superlattices

    SciTech Connect (OSTI)

    Kotani, Teruhisa; Birner, Stefan; Lugli, Paolo; Hamaguchi, Chihiro

    2014-04-14

    We present theoretical investigations of miniband structures and optical properties of InAs/GaAs one-dimensional quantum dot superlattices (1D-QDSLs). The calculation is based on the multi-band kp theory, including the conduction and valence band mixing effects, the strain effect, and the piezoelectric effect; all three effects have periodic boundary conditions. We find that both the electronic and optical properties of the 1D-QDSLs show unique states which are different from those of well known single quantum dots (QDs) or quantum wires. We predict that the optical absorption spectra of the 1D-QDSLs strongly depend on the inter-dot spacing because of the inter-dot carrier coupling and changing strain states, which strongly influence the conduction and valence band potentials. The inter-miniband transitions form the absorption bands. Those absorption bands can be tuned from almost continuous (closely stacked QD case) to spike-like shape (almost isolated QD case) by changing the inter-dot spacing. The polarization of the lowest absorption peak for the 1D-QDSLs changes from being parallel to the stacking direction to being perpendicular to the stacking direction as the inter-dot spacing increases. In the case of closely stacked QDs, in-plane anisotropy, especially [110] and [11{sup }0] directions also depend on the inter-dot spacing. Our findings and predictions will provide an additional degree of freedom for the design of QD-based optoelectronic devices.

  19. Strain-optic voltage monitor wherein strain causes a change in the optical absorption of a crystalline material

    DOE Patents [OSTI]

    Weiss, Jonathan D.

    1997-01-01

    A voltage monitor which uses the shift in absorption edge of crystalline material to measure strain resulting from electric field-induced deformation of piezoelectric or electrostrictive material, providing a simple and accurate means for measuring voltage applied either by direct contact with the crystalline material or by subjecting the material to an electric field.

  20. Halo mass dependence of H I and O VI absorption: evidence for differential kinematics

    SciTech Connect (OSTI)

    Mathes, Nigel L.; Churchill, Christopher W.; Nielsen, Nikole M.; Trujillo-Gomez, Sebastian; Kacprzak, Glenn G.; Charlton, Jane; Muzahid, Sowgat

    2014-09-10

    We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging and high-resolution HST/COS or HST/STIS quasar spectroscopy of Lyα, Lyβ, and O VI λλ1031, 1037 absorption. The galaxies, having 10.8 ≤ log (M {sub h}/M {sub ☉}) ≤ 12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R {sub vir} = 3. When the full range of M {sub h} and D/R {sub vir} of the sample are examined, ∼40% of the H I absorbing clouds can be inferred to be escaping their host halo. The fraction of bound clouds decreases as D/R {sub vir} increases such that the escaping fraction is ∼15% for D/R {sub vir} < 1, ∼45% for 1 ≤ D/R {sub vir} < 2, and ∼90% for 2 ≤ D/R {sub vir} < 3. Adopting the median mass log M {sub h}/M {sub ☉} = 11.5 to divide the sample into 'higher' and 'lower' mass galaxies, we find a mass dependency for the hot circumgalactic medium kinematics. To our survey limits, O VI absorption is found in only ∼40% of the H I clouds in and around lower mass halos as compared to ∼85% around higher mass halos. For D/R {sub vir} < 1, lower mass halos have an escape fraction of ∼65%, whereas higher mass halos have an escape fraction of ∼5%. For 1 ≤ D/R {sub vir} < 2, the escape fractions are ∼55% and ∼35% for lower mass and higher mass halos, respectively. For 2 ≤ D/R {sub vir} < 3, the escape fraction for lower mass halos is ∼90%. We show that it is highly likely that the absorbing clouds reside within 4R {sub vir} of their host galaxies and that the kinematics are dominated by outflows. Our finding of 'differential kinematics' is consistent with the scenario of 'differential wind recycling' proposed by Oppenheimer et al. We discuss the implications for galaxy evolution, the stellar to halo mass function, and the mass-metallicity relationship of galaxies.

  1. A Remote Absorption Process for Disposal of Evaporate and Reverse Osmosis Concentrates

    SciTech Connect (OSTI)

    Brunsell, D.A.

    2008-07-01

    100% scalable from a concentrate test sample as small as 50 grams to full-scale processing of 100 cubic foot containers or larger. In summary: The absorption process offers utilities a viable and less costly alternative to on-site drying or solidification of concentrates. The absorption process can be completed by site personnel or by a vendor as a turnkey service. The process is suitable for multiple types of waste, including RO and evaporator concentrates, sludges, and other difficult to process waters and wet solids. (author)

  2. In vitro dermal absorption of pyrethroid pesticides in human and rat skin

    SciTech Connect (OSTI)

    Hughes, Michael F.; Edwards, Brenda C.

    2010-07-15

    Dermal exposure to pyrethroid pesticides can occur during manufacture and application. This study examined the in vitro dermal absorption of pyrethroids using rat and human skin. Dermatomed skin from adult male Long Evans rats or human cadavers was mounted in flow-through diffusion cells, and radiolabeled bifenthrin, deltamethrin or cis-permethrin was applied in acetone to the skin. Fractions of receptor fluid were collected every 4 h. At 24 h, the skins were washed with soap and water to remove unabsorbed chemical. The skin was then solubilized. Two additional experiments were performed after washing the skin; the first was tape-stripping the skin and the second was the collection of receptor fluid for an additional 24 h. Receptor fluid, skin washes, tape strips and skin were analyzed for radioactivity. For rat skin, the wash removed 53-71% of the dose and 26-43% remained in the skin. The cumulative percentage of the dose at 24 h in the receptor fluid ranged from 1 to 5%. For human skin, the wash removed 71-83% of the dose and 14-25% remained in the skin. The cumulative percentage of the dose at 24 h in the receptor fluid was 1-2%. Tape-stripping removed 50-56% and 79-95% of the dose in rat and human skin, respectively, after the wash. From 24-48 h, 1-3% and about 1% of the dose diffused into the receptor fluid of rat and human skin, respectively. The pyrethroids bifenthrin, deltamethrin and cis-permethrin penetrated rat and human skin following dermal application in vitro. However, a skin wash removed 50% or more of the dose from rat and human skin. Rat skin was more permeable to the pyrethroids than human skin. Of the dose in skin, 50% or more was removed by tape-stripping, suggesting that permeation of pyrethroids into viable tissue could be impeded. The percentage of the dose absorbed into the receptor fluid was considerably less than the dose in rat and human skin. Therefore, consideration of the skin type used and fractions analyzed are important when using

  3. NEW PERSPECTIVE ON GALAXY OUTFLOWS FROM THE FIRST DETECTION OF BOTH INTRINSIC AND TRAVERSE METAL-LINE ABSORPTION

    SciTech Connect (OSTI)

    Kacprzak, Glenn G.; Cooke, Jeff; Martin, Crystal L.; Ho, Stephanie H.; Bouch, Nicolas; LeReun, Audrey; Schroetter, Ilane; Churchill, Christopher W.; Klimek, Elizabeth

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Ly?, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V {sub dtb} = 45-255 km s{sup 1}. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V {sub outflow} = 40-80 km s{sup 1} to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V {sub dtb}. The galaxy has a metallicity, derived from H? and N II, of [O/H] = 0.21 0.08, whereas the transverse absorption has [X/H] = 1.12 0.02. The galaxy star formation rate is constrained between 4.6-15 M {sub ?} yr{sup 1} while the estimated outflow rate ranges between 1.6-4.2 M {sub ?} yr{sup 1} and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ?1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  4. Structural stability of 1100[degree]C heated Pd/k during absorption cycling in protium. [Palladium supported on kieselguhr

    SciTech Connect (OSTI)

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110[degree]C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100[degree]C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100[degree]C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100[degree]C.

  5. Characterization of the Electronic Structure of Silicon Nanoparticles Using X-ray Absorption and Emission

    SciTech Connect (OSTI)

    Vaverka, A M

    2008-07-15

    Resolving open questions regarding transport in nanostructures can have a huge impact on a broad range of future technologies such as light harvesting for energy. Silicon has potential to be used in many of these applications. Understanding how the band edges of nanostructures move as a function of size, surface termination and assembly is of fundamental importance in understanding the transport properties of these materials. In this thesis work I have investigated the change in the electronic structure of silicon nanoparticle assemblies as the surface termination is changed. Nanoparticles are synthesized using a thermal evaporation technique and sizes are determined using atomic force microscopy (AFM). By passivating the particles with molecules containing alcohol groups we are able to modify the size dependent band edge shifts. Both the valence and conduction bands are measured using synchrotron based x-ray absorption spectroscopy (XAS) and soft x-ray fluorescence (SXF) techniques. Particles synthesized via recrystallization of amorphous silicon/SiO{sub 2} multilayers of thicknesses below 10 nm are also investigated using the synchrotron techniques. These samples also show quantum confinement effects but the electronic structure is different from those synthesized via evaporation methods. The total bandgap is determined for all samples measured. The origins of these differences in the electronic structures are discussed.

  6. Magnetic nanoparticles for power absorption: Optimizing size, shape and magnetic properties

    SciTech Connect (OSTI)

    Gonzalez-Fernandez, M.A.; Torres, T.E.; Andres-Verges, M.; Costo, R.; Presa, P. de la; Serna, C.J.; Morales, M.P.; Marquina, C.; Ibarra, M.R.; Goya, G.F.

    2009-10-15

    We present a study on the magnetic properties of naked and silica-coated Fe{sub 3}O{sub 4} nanoparticles with sizes between 5 and 110 nm. Their efficiency as heating agents was assessed through specific power absorption (SPA) measurements as a function of particle size and shape. The results show a strong dependence of the SPA with the particle size, with a maximum around 30 nm, as expected for a Neel relaxation mechanism in single-domain particles. The SiO{sub 2} shell thickness was found to play an important role in the SPA mechanism by hindering the heat outflow, thus decreasing the heating efficiency. It is concluded that a compromise between good heating efficiency and surface functionality for biomedical purposes can be attained by making the SiO{sub 2} functional coating as thin as possible. - Graphical Abstract: The magnetic properties of Fe{sub 3}O{sub 4} nanoparticles from 5 to 110 nm are presented, and their efficiency as heating agents discussed as a function of particle size, shape and surface functionalization.

  7. Clean coal technology III 10 MW demonstration of gas suspension absorption. Final public design report

    SciTech Connect (OSTI)

    1995-06-01

    This report provides the nonproprietary design information for the ``10 MW Demonstration of Gas Suspension Absorption (GSA)`` Demonstration Project at Tennessee Valley Authority`s (TVA) Shawnee Power Station, Center for Emission Research (CER). The 10 MW Demonstration of GSA program is designed to demonstrate the performance of the GSA system in treating the flue gas from a boiler burning high sulfur coal. This project involves design, manufacturing, construction and testing of a retrofitted GSA system. This report presents a nonproprietary description of the technology and overall process performance requirements, plant location and plant facilities. The process, mechanical, structural and electrical design of the GSA system as well as project cost information are included. It also includes a description the modification or alterations made during the course of construction and start-up. Plant start-up provisions, environmental considerations and control, monitoring and safety considerations are also addressed for the process. This report, initially drafted in 1993, covers design information available prior to startup of the demonstration project. It does not reflect the results obtained in that project, which is now complete.

  8. Limits on Variations in Fundamental Constants from 21-cm and Ultraviolet Quasar Absorption Lines

    SciTech Connect (OSTI)

    Tzanavaris, P.; Webb, J.K.; Flambaum, V.V.; Curran, S.J.; Murphy, M.T.

    2005-07-22

    Quasar absorption spectra at 21-cm and UV rest wavelengths are used to estimate the time variation of x{identical_to}{alpha}{sup 2}g{sub p}{mu}, where {alpha} is the fine structure constant, g{sub p} the proton g factor, and m{sub e}/m{sub p}{identical_to}{mu} the electron/proton mass ratio. Over a redshift range 0.24 < or approx. z{sub abs} < or approx. 2.04, <{delta}x/x>{sub total}{sup weighted}=(1.17{+-}1.01)x10{sup -5}. A linear fit gives x/x=(-1.43{+-}1.27)x10{sup -15} yr{sup -1}. Two previous results on varying {alpha} yield the strong limits {delta}{mu}/{mu}=(2.31{+-}1.03)x10{sup -5} and {delta}{mu}/{mu}=(1.29{+-}1.01)x10{sup -5}. Our sample, 8x larger than any previous, provides the first direct estimate of the intrinsic 21-cm and UV velocity differences {approx}6 km s{sup -1}.

  9. Near-Edge X-Ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    SciTech Connect (OSTI)

    Willey, T.M.; Fabbri, J.D.; Lee, J.R.I.; Schreiner, P.R.; Fokin, A.A.; Tkachenko, B.A.; Fokina, N.A.; Dahl, J.E.P.; Carlson, R.M.K.; Vance, A.L.; Yang, W.; Terminello, L.J.; Buuren, T.van; Melosh, N.A.

    2009-05-26

    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 and 0.16 {+-} 0.04 eV, respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different degrees of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond nanoparticles.

  10. Near-Edge X-ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    SciTech Connect (OSTI)

    Willey, T M; Fabbri, J; Lee, J I; Schreiner, P; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J; Carlson, B; Vance, A L; Yang, W; Terminello, L J; van Buuren, T; Melosh, N

    2007-11-27

    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface-modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 eV and 0.16 {+-} 0.04 eV respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different amounts of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond clusters.

  11. Attosecond transient absorption probing of electronic superpositions of bound states in neon. Detection of quantum beats

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Beck, Annelise R; Bernhardt, Birgitta; Warrick, Erika R.; Wu, Mengxi; Chen, Shaohao; Gaarde, Mette B.; Schafer, Kenneth J.; Neumark, Daniel M.; Leone, Stephen R.

    2014-11-07

    Electronic wavepackets composed of multiple bound excited states of atomic neon lying between 19.6 and 21.5 eV are launched using an isolated attosecond pulse. Individual quantum beats of the wavepacket are detected by perturbing the induced polarization of the medium with a time-delayed few-femtosecond near-infrared (NIR) pulse via coupling the individual states to multiple neighboring levels. All of the initially excited states are monitored simultaneously in the attosecond transient absorption spectrum, revealing Lorentzian to Fano lineshape spectral changes as well as quantum beats. The most prominent beating of the several that were observed was in the spin–orbit split 3d absorptionmore » features, which has a 40 femtosecond period that corresponds to the spin–orbit splitting of 0.1 eV. The few-level models and multilevel calculations confirm that the observed magnitude of oscillation depends strongly on the spectral bandwidth and tuning of the NIR pulse and on the location of possible coupling states.« less

  12. A multi-channel monolithic Ge detector system for fluorescence x-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Bucher, J.J.; Allen, P.G.; Edelstein, N.M.; Shuh, D.K.; Madden, N.W.; Cork, C.; Luke, P.; Pehl, D.; Malone, D.

    1995-03-01

    Construction and performance of a monolithic quad-pixel Ge detector for fluorescence x-ray absorption spectroscopy (XAS) at synchrotron radiation sources are described. The detector semiconductor element has an active surface area of 4.0 cm{sup 2} which is electrically separated into four 1.0 cm{sup 2} pixels, with little interfacial dead volume. Spatial response of the array shows that cross-talk between adjacent pixels is < 10% for 5.9 keV photons that fall within 0.5 mm of the pixel boundaries. The detector electronics system uses pre-amplifiers built at LBNL with commercial Tennelec Model TC 244 amplifiers. Using an {sup 55}Fe test source (MnK{sub {alpha}}, 5.9 keV), energy resolution of better than 200 eV is achieved with a 4 {mu}sec peaking time. At 0.5 {mu}sec peaking time, pulse pileup results in a 75% throughput efficiency for an incoming count rate of 100 kHz. Initial XAS fluoresncece measurements at the beamline 4 wiggler end stations at SSRL show that the detector system has several advantages over commercial x-ray spectrometers for low-concentration counting.

  13. Optoelectronic properties of Mg{sub 2}Si semiconducting layers with high absorption coefficients

    SciTech Connect (OSTI)

    Kato, Takashi; Sago, Yuichiro; Fujiwara, Hiroyuki

    2011-09-15

    In an attempt to develop a low-cost material for solar cell devices, polycrystalline magnesium silicide (poly-Mg{sub 2}Si) semiconducting layers have been prepared by applying rf magnetron sputtering using a Mg{sub 2}Si target. The optimum substrate temperature for the poly-Mg{sub 2}Si growth was found to be T{sub s} = 200 deg. C; the film deposition at higher temperatures leads to desorption of Mg atoms from the growing surface, while the amorphous phase formation occurs at room temperature. The poly-Mg{sub 2}Si layer deposited at T{sub s} = 200 deg. C shows the (111) preferential orientation with a uniform grain size of {approx}50 nm. The dielectric function of the poly-Mg{sub 2}Si layer has been determined accurately by spectroscopic ellipsometry. From the analysis, quite high absorption coefficients and an indirect gap of 0.77 eV in the poly-Mg{sub 2}Si layer have been confirmed. The above poly-Mg{sub 2}Si layer shows clear photoconductivity and can be applied as a narrow-gap bottom layer in multi-junction solar cell devices.

  14. Near-infrared light absorption by polycrystalline SiSn alloys grown on insulating layers

    SciTech Connect (OSTI)

    Kurosawa, Masashi; Kato, Motohiro; Yamaha, Takashi; Taoka, Noriyuki; Nakatsuka, Osamu; Zaima, Shigeaki

    2015-04-27

    High-Sn-content SiSn alloys are strongly desired for the next-generation near-infrared optoelectronics. A polycrystalline growth study has been conducted on amorphous SiSn layers with a Sn-content of 2%30% deposited on either a substrate of SiO{sub 2} or SiN. Incorporating 30% Sn into Si permits the crystallization of the amorphous layers at annealing temperatures below the melting point of Sn (231.9?C). Composition analyses indicate that approximately 20% of the Sn atoms are substituted into the Si lattice after solid-phase crystallization at 150220?C for 5?h. Correspondingly, the optical absorption edge is red-shifted from 1.12?eV (Si) to 0.83?eV (Si{sub 1?x}Sn{sub x} (x???0.18??0.04)), and the difference between the indirect and direct band gap is significantly reduced from 3.1?eV (Si) to 0.22?eV (Si{sub 1?x}Sn{sub x} (x???0.18??0.04)). These results suggest that with higher substitutional Sn content the SiSn alloys could become a direct band-gap material, which would provide benefits for Si photonics.

  15. Performance of a double-effect absorption chiller driven by ICPC solar collectors

    SciTech Connect (OSTI)

    Bergquam, J.B.; Duff, W.S.; Brezner, J.M.; Henkel, E.T.; Winston, R.; O'Gallagher, J.; Sethi, P.

    1999-07-01

    This paper presents experimental data and analytical results describing the performance of a 70 kW (20 ton), water-fired, double-effect absorption chiller. The chiller is driven by a 106 m{sup 2} array of integrated compound parabolic concentrator (ICPC) solar collectors. For this project, an existing gas-fired chiller was modified to operate on hot water. The water was heated by an array of 336 evacuated ICPC tubes. Each tube has an effective area of 0.317 m{sup 2}. The chiller and collector array are part of a complete solar HVAC system that provides air conditioning and space heating for a 743 m{sup 2} (8,000 ft{sup 2}) commercial building in Sacramento, CA. The other components of the HVAC system are a high temperature storage tank, a cooling tower, a gas-fired back-up boiler and five 14 kW (4 ton) cooling/heating fan coil units. The experimental data are used to determine; (1) the efficiency of the collectors; (2) the coefficient of performance of the chiller; and (3) the overall energy balance on the system. Computer models have also been developed to predict the performance and to optimize the design and operating characteristics of the HVAC system.

  16. Modeling the performance of small capacity lithium bromide-water absorption chiller operated by solar energy

    SciTech Connect (OSTI)

    Saman, N.F.; Sa`id, W.A.D.K.

    1996-12-31

    An analysis of the performance of a solar operated small capacity (two-ton) Lithium Bromide-Water (LiBr-H{sub 2}O) absorption system is conducted. The analysis is based on the first law of thermodynamics with lithium bromide as the absorbent and water as the refrigerant. The effect of various parameters affecting the machine coefficient of performance under various operating conditions is reported. Coefficient of performance of up to 0.8 can be obtained using flat plate solar collectors with generator temperatures in the range of 80--95 C (176--203 F). Liquid heat exchangers with effectiveness based on an NTU of the order of one would be a good design choice. The chiller can save approximately 3,456 kWh/yr per a two-ton unit, and it will reduce emissions by 19 lb of NO{sub x}, 5,870 lb of CO{sub 2}, and 16 lb of SO{sub x} per year per machine.

  17. X-ray absorption fine structure spectroscopic study of uranium nitrides

    SciTech Connect (OSTI)

    Poineau, Frederic; Yeamans, Charles B.; Cerefice, Gary S.; Sattelberger, Alfred P; Czerwinski, Ken R.

    2012-01-01

    Uranium mononitride (UN), sesquinitride (U2N3) and dinitride (UN2) were characterized by extended X-Ray absorption fine structure spectroscopy. Analysis on UN indicate the presence of three uranium shells at distances of 3.46(3), 4.89(5) and 6.01(6) A and a nitrogen shell at a distance of 2.46(2) A . For U2N3, two absorbing uranium atoms at different crystallographic positions are present in the structure. One of the uranium atoms is surrounded by nitrogen atoms at 2.28(2) A and by uranium atoms at 3.66(4) and 3.95(4) A . The second type of uranium atom is surrounded by nitrogen atoms at 2.33(2) and 2.64(3) A and by uranium atoms at 3.66(4), 3.95(4) and 5.31(5) A . Results on UN2 indicate two uranium shells at 3.71(4) and 5.32(5) A and two nitrogen shells at 2.28(2).

  18. Simulation and performance analysis of a 4-effect lithium bromide-water absorption chiller

    SciTech Connect (OSTI)

    Grossman, G.; Zaltash, A.; DeVault, R.C.

    1995-02-01

    Performance simulation has been conducted for a 4-effect lithium bromide-water chiller, capable of substantial performance improvement over state-of-the-art double-effect cycles. The system investigated includes four condensers and four desorbers coupled together, forming an extension of the conventional double-effect cycle; based on prior analytical studies, a parallel flow system was preferred over series flow, and double-condenser coupling was employed, to further improve performance. A modular computer code for simulation of absorption systems (ABSIM) was used to investigate the performances of the cycle. The simulation was carried out to investigate the influence of some major design parameters. A coefficient of performance around 2.0 (cooling) was calculated at the design point, with a heat supply temperature of 600{degrees}F (315{degrees}C) at the solution outlet from the high temperature desorber. With some optimization of the weak (pumped) solution flowrate and of the solution split among the four desorbers, this COP may be raised above 2.2.

  19. OBSERVING THE END OF COLD FLOW ACCRETION USING HALO ABSORPTION SYSTEMS

    SciTech Connect (OSTI)

    Stewart, Kyle R.; Kaufmann, Tobias; Bullock, James S.; Barton, Elizabeth J.; Maller, Ariyeh H.; Diemand, Juerg; Wadsley, James

    2011-07-01

    We use cosmological smoothed particle hydrodynamic simulations to study the cool, accreted gas in two Milky Way size galaxies through cosmic time to z = 0. We find that gas from mergers and cold flow accretion results in significant amounts of cool gas in galaxy halos. This cool circum-galactic component drops precipitously once the galaxies cross the critical mass to form stable shocks, M{sub vir} = M{sub sh} {approx} 10{sup 12} M{sub sun}. Before reaching M{sub sh}, the galaxies experience cold mode accretion (T < 10{sup 5} K) and show moderately high covering fractions in accreted gas: f{sub c} {approx} 30%-50% for R < 50 comoving kpc and N{sub Hi}>10{sup 16} cm{sup -2}. These values are considerably lower than observed covering fractions, suggesting that outflowing gas (not included here) is important in simulating galaxies with realistic gaseous halos. Within {approx}500 Myr of crossing the M{sub sh} threshold, each galaxy transitions to hot mode gas accretion, and f{sub c} drops to {approx}5%. The sharp transition in covering fraction is primarily a function of halo mass, not redshift. This signature should be detectable in absorption system studies that target galaxies of varying host mass, and may provide a direct observational tracer of the transition from cold flow accretion to hot mode accretion in galaxies.

  20. MOSFIRE ABSORPTION LINE SPECTROSCOPY OF z > 2 QUIESCENT GALAXIES: PROBING A PERIOD OF RAPID SIZE GROWTH

    SciTech Connect (OSTI)

    Belli, Sirio; Ellis, Richard S.; Konidaris, Nick P.; Newman, Andrew B.

    2014-06-20

    Using the MOSFIRE near-infrared multi-slit spectrograph on the Keck 1 Telescope, we have secured high signal-to-noise ratio absorption line spectra for six massive galaxies with redshift 2 < z < 2.5. Five of these galaxies lie on the red sequence and show signatures of passive stellar populations in their rest-frame optical spectra. By fitting broadened spectral templates we have determined stellar velocity dispersions and, with broad-band Hubble Space Telescope and Spitzer photometry and imaging, stellar masses and effective radii. Using this enlarged sample of galaxies, we confirm earlier suggestions that quiescent galaxies at z > 2 have small sizes and large velocity dispersions compared to local galaxies of similar stellar mass. The dynamical masses are in very good agreement with stellar masses (log M {sub *}/M {sub dyn} = –0.02 ± 0.03), although the average stellar-to-dynamical mass ratio is larger than that found at lower redshift (–0.23 ± 0.05). By assuming evolution at fixed velocity dispersion, not only do we confirm a surprisingly rapid rate of size growth but we also consider the necessary evolutionary track on the mass-size plane and find a slope α = dlog R{sub e} /dlog M {sub *} ≳ 2 inconsistent with most numerical simulations of minor mergers. Both results suggest an additional mechanism may be required to explain the size growth of early galaxies.