Sample records for gaas gypsum plaster

  1. Gamma doses from phospho-gypsum plaster-board

    SciTech Connect (OSTI)

    O`Brien, R.S. [Australian Radiation Lab., Victoria (Australia)

    1997-01-01T23:59:59.000Z

    The use of phospho-gypsum plaster-board and plaster cement in buildings as a substitute for natural gypsum may constitute an additional source of radiation exposure to both workers and members of the public, both from inhalation of radon progeny produced from radon which is exhaled from the plaster-board and from beta and gamma radiation produced by radioactive decay in the plaster-board. The calculations presented in this paper indicate that if phospho-gypsum sheets 1 cm thick containing a {sup 226}Ra concentration of 400 Bq kg{sup -1} are used to line the walls and ceiling of a room of dimensions up to 5 m {times} 5 m {times} 3 m, the annual effective dose from gamma radiation for a person continually occupying the room should not exceed approximately 0.13 mSv. This compares with a measured annual average effective dose from gamma radiation in Australian homes of 0.9 mSv. The annual effective dose from such thin sheets is directly proportional to the {sup 226}Ra concentration in the plaster-board. 13 refs., 6 figs.

  2. Estimates of inhalation doses resulting from the possible use of phospho-gypsum plaster-board in Australian homes

    SciTech Connect (OSTI)

    O`Brien, R.S.; Peggie, J.R.; Leith, I.S. [Australian Radiation Laboratory, Victoria (Australia)

    1995-04-01T23:59:59.000Z

    Current materials used as internal lining in Australian buildings ade based on natural gypsum of low radium content. A study was carried out to estimate the contribution to the annual effective dose due to airborne contamination from chemical by-product gypsum plaster board of higher radium content if it were used as an internal lining.

  3. FGD gypsum issues

    SciTech Connect (OSTI)

    Buecker, B.

    2007-11-15T23:59:59.000Z

    The article first explains how gypsum by-product is produced in flue gas desulfurization systems in coal-fired power plants. It goes on to talk about the main markets for gypsum - wallboard manufacture (Plaster of Paris), cement production and soil stabilization. In the USA in 2006 41.6 million tons of gypsum was used by manufacturers of wallboard and plaster products, 3.0 mt for cement production and 1.1 mt for agricultural purposes. A method of determining the by-product gypsum content by thermogravimetric analysis is outlined. 4 refs., 1 fig.

  4. Use of waste gypsum to replace natural gypsum as set retarders in portland cement

    SciTech Connect (OSTI)

    Chandara, Chea; Azizli, Khairun Azizi Mohd [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Ahmad, Zainal Arifin [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)], E-mail: zainal@eng.usm.my; Sakai, Etsuo [Tokyo Institute of Technology, Graduate School of Science and Engineering, Department of Metallurgy and Ceramic Science, 2-12-1 Meguro-ku, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2009-05-15T23:59:59.000Z

    The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5 wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.

  5. Socio-economic and Environmental Impact Analysis of Khothagpa Gypsum Mine

    E-Print Network [OSTI]

    Galay, Karma

    2008-01-01T23:59:59.000Z

    impacts which the author of the study is not Impact Analysis of Khothagpa Gypsum Mine 71 familiar with, only obvious ones are reported below. i) Air pollution Dusts generated by various mining activities are of major concern to the people living... in the nearby areas. Dust is generated by blasting, loading and haulage, vehicular movements, open air disposal of waste rocks, drilling, and crushing. These fugitive dusts from mine site as well as from the factory of Druk Plaster and Chemicals Limited...

  6. 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 [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Physics, Isparta (Turkey); Amasya University, Faculty of Arts and Sciences, Department of Physics, Amasya (Turkey); Suleyman Demirel University, Faculty of Technical Education, Department of Construction Education, Isparta (Turkey)

    2012-09-06T23:59:59.000Z

    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.

  7. Automatic 3D modeling of palatal plaster casts Marco Andreetto

    E-Print Network [OSTI]

    Abu-Mostafa, Yaser S.

    Automatic 3D modeling of palatal plaster casts Marco Andreetto Dept. of Information Engineer-form surfaces of anatomi- cal interest. 1. Introduction Plaster models derived from palate's impressions. A data-base with the 3D models of the plaster casts, which could be called a "virtual gypsotheque", can

  8. Discovery in Hydrating Plaster Using Multiple Machine Learning Methods

    E-Print Network [OSTI]

    Fernandez, Thomas

    Discovery in Hydrating Plaster Using Multiple Machine Learning Methods Judith E. Devaney, John G plaster over multiple time periods. We use three dimensional data obtained through X-ray microtomography of the plaster datasets that had been labeled with their autoclass predictions. The rules were found to have both

  9. Plaster Casts at Berkeley. Collections of the Hearst Museum of Anthropology & Department of Classics at UC Berkeley. An Exhibition of Rare Plaster Casts of Ancient Greek and Roman Sculpture. 2nd edition 2005, pp. vi + 76 + ii

    E-Print Network [OSTI]

    Miller, Stephen G.

    2005-01-01T23:59:59.000Z

    Britain: An Oxford Story of Plaster Casts from the Antique (sculptor Lysistratos took plaster impressions not only fromPlaster Casts at Berkeley COLLECTIONS OF THE HEARST MUSEUM

  10. Lasers Cleaning of Patrimonial Plasters E. Tanguy", N. Huet+, and A. Vinotte''

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Lasers Cleaning of Patrimonial Plasters E. Tanguy", N. Huet+, and A. Vinçotte'' 1 University as solution for the cleaningof ceramics and the plasters. Indeed in museums, these materials are often covered on plaster and with the effects on its morphologyand its crystallography. Plaster is an interesting material

  11. National Gypsum | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun JumpMuscoy,Jump9 CaseNatEl JumpGypsum Jump to:

  12. Building Stones

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    known as burnt gypsum or plaster of Paris. When mixedsolid material. Such gypsum plaster was produced from lateand painted. Gypsum plaster was also sometimes employed as a

  13. A study of production of {alpha}-form plaster from FGD sludge in an aqueous solution at atmospheric pressure

    SciTech Connect (OSTI)

    Tong, S. [Wuhan Yejin Univ. of Technology and Science, Wuhan, Hubei (China). Dept.of Chemical Engineering; Kirk, D. [Univ. of Toronto, Ontario (Canada). Dept. of Chemical Engineering

    1996-12-31T23:59:59.000Z

    A process for directly converting FGD sludge solid into {alpha}-form plaster in an aqueous solution at atmospheric pressure with simultaneous collection of SO{sub 2} evolved has been studied. The reactant suspension comprises FGD sludge solid in a ratio of solid to liquid from 1:1.25 to 1:10, sulfuric acid from 5% to 30%, alkali earth metal chloride salts no more than 8% which serves as the catalyst for crystallization. Experiments are proceeded in pH values from acidic range to near neutral range in a temperature range from 80 C to the near boiling point of suspension. It has been found that the concentrations of acid in liquid and the reaction temperature are the most sensitive factors to the rate of dehydration of FGD gypsum. Increasing the ratio of solid to liquid is disadvantageous for growth of crystals even though it does not effect obviously on the rate of dehydration of FGD gypsum. Addition of glycerol less than 3% plays a role in stabilizing {alpha}-form calcium sulfate hemihydrate crystals occurring in solution long enough so that crystals grow big. On the other hand, the pH range is the most important to modify crystal habit in presence of succinic acid. The more closed to the neutral range of pH value the liquid is adjusted, the better stability of the crystals appears, the more favorable for producing big squat crystals in high quality the process is believed.

  14. Development of Personality in Early and Middle Adulthood: Set Like Plaster or Persistent Change?

    E-Print Network [OSTI]

    Pillow, Jonathan

    Development of Personality in Early and Middle Adulthood: Set Like Plaster or Persistent Change-factor theory proposes the plaster hypothesis: All personality traits stop changing by age 30. In contrast

  15. Validation of Plaster Endocast Morphology Through 3D CT Image Analysis

    E-Print Network [OSTI]

    Schoenemann, P. Thomas

    Validation of Plaster Endocast Morphology Through 3D CT Image Analysis P. Thomas Schoenemann,1 by creating endo- casts out of rubber latex shells filled with plaster. The extent to which the method questions. Pairs of virtual endocasts (VEs) created from high-resolution CT scans of corresponding latex/plaster

  16. Metrological analysis of a procedure for the automatic 3D modeling of dental plaster casts

    E-Print Network [OSTI]

    Abu-Mostafa, Yaser S.

    Metrological analysis of a procedure for the automatic 3D modeling of dental plaster casts Nicola to an automatic procedure recently proposed for the 3D modeling of dental plaster casts. This contribution derives of an automatic 3D modeling procedure recently proposed and it shows the accuracy of 3D modeling dental plaster

  17. Durability of traditional plasters with respect to blast furnace slag-based plaster

    SciTech Connect (OSTI)

    Cerulli, T.; Pistolesi, C.; Maltese, C.; Salvioni, D

    2003-09-01T23:59:59.000Z

    Blast furnace slag is a residue of steel production. It is a latent hydraulic binder and is normally used to improve the durability of concrete and mortars. Slag could be also used as rendering mortar for masonry and old buildings. Today, cement and hydraulic lime are the most popular hydraulic binders used to make plasters. They are characterised by a low durability when exposed to the action of chemical and physical agents. The aim of this study was to provide a comparison between the physical-mechanical properties of some renders made with ordinary Portland cement, hydraulic lime, or slag. Furthermore, an investigation was carried out to analyse mortar resistance to several aggressive conditions like acid attack, freezing and thawing cycles, abrasion, sulphate aggression, cycles in ultraviolet screening device, and salt diffusion. The specimens, after chemical attack, have been characterised from the chemical-physical [specific surface according to the BET (Brunauer-Emmet-Teller) method], crystal-chemical (X-ray diffraction, XRD), and morphological (scanning electron microscopy, SEM) points of view.

  18. Recovery and utilization of gypsum and limestone from scrubber sludge. [Quarterly] technical report, March 1, 1993--May 31, 1993

    SciTech Connect (OSTI)

    Kawatra, S.K.; Eisele, T.C. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering

    1993-09-01T23:59:59.000Z

    Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}-2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project is investigating methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Work done in the previous quarter concentrated on developing a low-cost froth flotation process that could remove limestone, unburned carbon, and related contaminants from the sludge while recovering the bulk of the calcium sulfite and gypsum. In the current quarter, experiments to remove impurities from the sludge using a water-only cyclone were conducted. The cyclone has been found to be effective for removing the coarser limestone impurities, as well as removing contaminants such as fine gravel and grinding-ball chips. These results show that the cyclone will be very complementary with froth flotation, which mainly removes the very fine impurities.

  19. Recovery and utilization of gypsum and limestone from scrubber sludge. Technical report, December 1, 1992--February 28, 1993

    SciTech Connect (OSTI)

    Kawatra, S.K.; Eisele, T.C. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering; Banerjee, D. [Illinois Clean Coal Inst., Carterville, IL (United States)

    1993-05-01T23:59:59.000Z

    Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}-2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project is investigating methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Work done in the previous quarter concentrated on developing a dependable technique for analysis of scrubber sludge, so that it would be possible to determine exactly how well a particular purification process was working. This technique was then used to characterize the sludge from a particular Illinois power station. In the current quarter, studies were carried out using froth flotation to produce a product that could be oxidized to high-purity gypsum. These experiments have been quite successful, due to certain properties of the limestone impurity that makes it easier to remove by this method than was expected.

  20. Simplified Numerical Description of Latent Storage Characteristics for Phase Change Wallboard

    E-Print Network [OSTI]

    Fuestel, H.E.

    2011-01-01T23:59:59.000Z

    implemented in gypsum board, plaster or other wall-coveringimplemented in gypsum board, plaster or other wall-coveringbillion square meters of plaster board produced annually in

  1. About the Work of Art In the 1940s, Christian Petersen sculpted a plaster figure of George Washington Carver. He

    E-Print Network [OSTI]

    Mayfield, John

    About the Work of Art In the 1940s, Christian Petersen sculpted a plaster figure of George this sculpture in bronze as he originally intended, so he painted the work of art to resemble bronze. The plaster

  2. Characterization of several plasters and one retarder for repository sealing mixtures. Final report

    SciTech Connect (OSTI)

    Buck, A.D.; Burkes, J.P.; Reinhold, R.E.

    1985-09-01T23:59:59.000Z

    Samples of plasters (i.e., calcium sulfate hemihydrate, CaSO4.1/2H/sup 2/0) from six sources and one plaster retarder from a different source were obtained and characterized by a combination of chemical and physical testing and by petrographic examination. The petrographic examination included x-ray diffraction, optical microscopy, differential thermal analysis, and scanning electron microscopy procedures. The intent of this work was twofold. One purpose was to determine if plaster per se could be used as an ingredient for cementitious mixtures intended for repository sealing applications, Previous experience had been with use of a proprietary admixture that contained plaster. The second purpose was to determine one or more methods of distinguishing between the alpha and beta forms of calcium sulfate hemihydrate. Keywords: nuclear wastes; plaster of paris; tables(data).

  3. Virtualizing Ancient Rome: 3D acquisition and modeling of a large plaster-of-Paris model of imperial Rome

    E-Print Network [OSTI]

    Frischer, Bernard

    Virtualizing Ancient Rome: 3D acquisition and modeling of a large plaster-of-Paris model plaster-of-Paris model of imperial Rome (16x17 meters) created in the last century. Its overall size's urban history is well documented and studied. There is even a highly-regarded plaster-of-Paris model

  4. Recovery and utilization of gypsum and limestone from scrubber sludge. Final technical report, September 1, 1992--August 31, 1993

    SciTech Connect (OSTI)

    Kawatra, S.K.; Eisele, T.C. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering

    1993-12-31T23:59:59.000Z

    Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project investigated methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Two processes were studied, both separately and in combination: Water-only cycloning, and froth flotation. A large fraction (30--40%) of the impurities in the sludge are contained in the coarser, higher-density particles, which are readily removed using a water-only cyclone. Much of the remaining impurities are hydrophobic, and can be removed by froth flotation. A combined cyclone/froth flotation process has been found to be suitable for producing a high-purity product from scrubber sludge at low cost.

  5. Simulating corrosion-erosion mass transfer using plaster models

    SciTech Connect (OSTI)

    Griffith, P.; de Freitas, G.

    1989-01-01T23:59:59.000Z

    Corrosion-erosion is a term that covers a variety of processes leading to the removal of metal in low-carbon steel piping conveying water or steam/water mixtures at a temperature of 150 {+-} 50{degree}C. One of the most important of these processes is corrosion-dissolution. This is most likely to occur where disturbances or fittings cause local high velocities and thus high mass transfer coefficients. The wear equation, which requires the local mass transfer coefficient, is presented. This paper presents a way of determining the local mass transfer coefficient. This paper reports measurements of both local and nominal mass transfer coefficients on a plaster model of a defective weld in a pipe. Welds are particularly important because they are often the place where wear is the greatest and the pipe is most severely thinned.

  6. What You Need to Know About Gypsum

    E-Print Network [OSTI]

    Balser, Teri C.

    TestCa(ppm) Arlington Ashland Lancaster Spooner 0 100 200 300 400 500 600 700 SoilTestMg(ppm) Arlington Ashland applied (t/a) 5.8 6.0 6.2 6.4 6.6 6.8 7.0 SoilpH Arlington Ashland Lancaster Spooner 5.8 6.0 6.2 6.4 6.6 6.8 7.0 7.2 SoilpH Arlington Ashland Lancaster Spooner 0 1 4 16 Effect of gypsum additions on soil p

  7. Flue gas desulfurization gypsum and fly ash

    SciTech Connect (OSTI)

    Not Available

    1992-05-01T23:59:59.000Z

    The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority`s newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned for all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective.

  8. Properties study of cotton stalk fiber/gypsum composite

    SciTech Connect (OSTI)

    Li Guozhong; Yu Yanzhen; Zhao Zhongjian; Li Jianquan; Li Changchun

    2003-01-01T23:59:59.000Z

    This manuscript addresses treating cotton stalk fiber surface with styrene acrylic emulsion, which improves the interfacial combined state of cotton stalk fiber/gypsum composite effectively and improves its mechanical properties notably. Mixes less slag, ordinary Portland cement, etc., to modify gypsum base. The electron microscope was utilized to analyze and research on the effect on composite properties of the abovementioned mixtures.

  9. E-Print Network 3.0 - actively forming gypsum Sample Search Results

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

    for formation of gypsum) for the reference solution... by ICP-mass spectroscopy analysis for calcium. 4. Results and discussion Gypsum scale can form due... of...

  10. Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

    SciTech Connect (OSTI)

    Jessica Marshall Sanderson

    2006-06-01T23:59:59.000Z

    This report presents and discusses results from Task 5 of the study ''Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,'' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. The FGD process is used to control the sulfur dioxide emissions which would result in acid rain if not controlled. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies developed for power plants involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the synthetic gypsum material is used as a feedstock for wallboard production. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope includes five discrete tasks, each conducted at various USG wallboard plants using synthetic gypsum from different FGD systems. The five tasks were to include (1) a baseline test, then variations representing differing power plant (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5, which was to evaluate gypsum produced from an alternate FGD reagent, could not be conducted as planned. Instead, Task 5 was conducted at conditions similar to a previous task, Task 3, although with gypsum from an alternate FGD system. In this project, process stacks in the wallboard plant have been sampled using the Ontario Hydro method. The stack locations sampled for each task include a dryer for the wet gypsum as it enters the plant and a gypsum calciner. The stack of the dryer for the wet wallboard product was also tested as part of this task, and was tested as part of Tasks 1 and 4. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. The Ontario Hydro results, process sample mercury concentration data, and process data were used to construct mercury mass balances across the wallboard plants. Task 5 was conducted at a wallboard plant processing synthetic gypsum from a power plant that fires Eastern bituminous coal. The power plant is equipped with a selective catalytic reduction (SCR) system for NOX emissions control, but the SCR was bypassed during the time period the gypsum tested was produced. The power plant has a single-loop, open spray tower, limestone reagent FGD system, with forced oxidation conducted in a reaction tank integral with the FGD absorber. The FGD system has gypsum fines blow down as part of the dewatering step. Gypsum fines blow down is believed to be an important variable that impacts the amount of mercury in the gypsum byproduct and possibly its stability during the wallboard process. The results of the Task 5 stack testing, as measured by the Ontario Hydro method, detected that an average of 51% of the incoming mercury in the FGD gypsum was emitted during wallboard production. These losses were distributed as 2% or less each across the wet gypsum dryer and product wallboard dryer, and about 50% across the gypsum calciner. Emissions were similar to what Task 3 results showed, on both a percentage and a mass basis, for gypsum produced by a power plant firing bituminous coal and also having gypsum fines blow down as part of the FGD dewatering scheme. As was seen in the Task 1 through 4 results, most of the mercury detected in the stack testing on the wet gypsum dryer and kettle calciner was in the form of elemental mercury. In the wallboard dryer kiln, a more signific

  11. Using lasers for cleaning ceramic and plaster patrimonial objects. Nathalie HUET1*, Eric TANGUy2, Armand VINOTTE1, Vassilis ZAFIROPULOS3

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Using lasers for cleaning ceramic and plaster patrimonial objects. Nathalie HUET1*, Eric TANGUy2 or damaging on some ceramics and plaster objects. It's especially true on outdoor ceraIJ?CScovered with black crust or indoor biscuits wares and plasters exposed to dust and repeated handling. The use of lasers

  12. Decoupling of uranium metal with borated plaster using /sup 252/Cf nose analysis methods

    SciTech Connect (OSTI)

    Mihalczo, J.T.; King, W.T.; Blakeman, E.D.

    1985-01-01T23:59:59.000Z

    The use of borated plaster to isolate uranium (93.2 wt % /sup 235/U) metal was studied in a series of subcritical experiments with uranium metal cylinders (7.0 in. diam, 2.0 in. thick) and slabs (approx.1.4 x approx.5.4 x approx.10.1 in. dimensions). In the cylindrical experiments, the thickness of borated plaster was varied up to 10 in. and the subcriticality measured using the /sup 252/Cf-source-driven neutron noise analysis method. In the experiments with the uranium slabs, an array of slabs 3 wide and 8 high was assembled in steps to demonstrate the subcriticality of this array with 3.75-in.-thick borated plaster as an isolating material between all uranium slabs. In the slab experiments, both noise analysis and source neutron multiplication measurements were performed. Before assembly of the slab array the presence of boron in the plaster was verified by neutron transmission and gamma-ray spectrometry measurements.

  13. Thermo-mechanical model of a cardboard-plaster-cardboard composite

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Thermo-mechanical model of a cardboard-plaster-cardboard composite plate submitted to fire load Mechanics laboratory, Marne-la-Vall´ee University, France Abstract Generally, the standard rules require with experiments in order to predict thermo- mechanical overall partition behaviour. This research is organized

  14. Use of Ekibastuzsk coal ash as a filler for acid resistant plaster

    SciTech Connect (OSTI)

    Korsakov, F.F.; Isichenko, I.I.; Kabanov, G.A.

    1981-01-01T23:59:59.000Z

    Acid resistant plasters are used extensively at thermal power plants for protection of gas conduits, ash traps with spouts and hydraulic valves, and the internal surfaces of smoke pump housings. The surface being protected is preliminarily cleaned and a No. 16-20 steel grid attached to the surface by electrial welding. In producing the acid resistant plaster, 14-17 parts by weight of sodium silicofluoride are added to 100 parts by weight of sodium water glass; the remainder consists of andesite or diabase meal to the required consistency. The water glass fulfills the role of a binder; the sodium silicofluoride accelerates solidification of the water glass and the andesite and diabase meal serve as fillers. We found, tested in the laboratory and used successfully (under experimental-industrial conditions) a substitute for andesite and diabase meal. This substitute was ash of Ekibastuzsk coal, which was not only comparable to the meal in regard to quality of the acid resistant plaster, but even exceeded andesite and diabase meal in regard to several qualitative indicators. At the present time, a formula is being developed for an acid resistant plaster produced on the basis of water glass, sodium silicofluoride and ash of Ekibastuzsk coal. In order to verify the possibility of using other ashes instead of andesite and diabase meal, we also tested, under laboratory conditions, acid resistant plasters using ash from thermal power plants (TPP's) also burning Karagandinsk, Kuuchekinsk, Kuznetsk and Kansko-Achinsk coals. In compositions produced with polymer binders, Kansko-Achinsk coal ash was one of the best fillers, providing the most favorable physico-mechanical properties of the composition.

  15. Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

    SciTech Connect (OSTI)

    Jessica Sanderson

    2007-12-31T23:59:59.000Z

    This report presents and discusses results from the project 'Fate of Mercury in Synthetic Gypsum Used for Wallboard Production', performed at five different full-scale commercial wallboard plants. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies involve the capture of mercury in FGD systems. The objective of this study has been to determine whether any mercury is released into the atmosphere at wallboard manufacturing plants when the synthetic gypsum material is used as a feedstock for wallboard production. The project has been co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope included seven discrete tasks, each including a test conducted at various USG wallboard plants using synthetic gypsum from different wet FGD systems. The project was originally composed of five tasks, which were to include (1) a base-case test, then variations representing differing power plant: (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5,could not be conducted as planned and instead was conducted at conditions similar to Task 3. Subsequently an opportunity arose to test gypsum produced from the Task 5 FGD system, but with an additive expected to impact the stability of mercury, so Task 6 was added to the project. Finally, Task 7 was added to evaluate synthetic gypsum produced at a power plant from an additional coal type. In the project, process stacks in the wallboard plant were sampled using the Ontario Hydro method. In every task, the stack locations sampled included a gypsum dryer and a gypsum calciner. In Tasks 1 and 4 through 7, the stack of the dryer for the wet wallboard product was also tested. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. These results and process data were used to construct mercury mass balances across the wallboard plants. The results from the project showed a wide range of percentage mercury losses from the synthetic gypsum feedstocks as measured by the Ontario Hydro method at the process stacks, ranging from 2% to 55% of the mercury in the gypsum feedstock. For the tasks exceeding 10% mercury loss across the wallboard plant, most of the loss occurred across the gypsum calciner. When total wallboard emissions remained below 10%, the primary emission location varied with a much less pronounced difference in emission between the gypsum dryer, calciner and board dryer. For all seven tasks, the majority of the mercury emissions were measured to be in the elemental form (Hg{sup 0}). Overall, the measured mercury loss mass rates ranged from 0.01 to 0.17 grams of mercury per dry ton of synthetic gypsum processed, or 0.01 to 0.4 pounds of mercury released per million square feet of wallboard produced from synthetic gypsum. The Coal Combustion Product Production and Use Survey from the American Coal Ash Association (ACAA) indicate that 7,579,187 short tons of synthetic gypsum were used for wallboard production in 2006. Extrapolating the results of this study to the ACAA industry usage rate, we estimate that mercury releases from wallboard production plants in 2006 ranged between 150 to 3000 pounds for the entire U.S. wallboard industry. With only seven sets of wallboard plant measurements, it is difficult to draw firm conclusions about what variables impact the mercury loss percentages across the wallboard plants. One significant o

  16. Department of Mechanical Engineering Spring 2013 CFD Model of a Gypsum Mixer

    E-Print Network [OSTI]

    Demirel, Melik C.

    PENNSTATE Department of Mechanical Engineering Spring 2013 CFD Model of a Gypsum Mixer Overview This project, in continuation of last semester's team, intends to create a computational fluid dynamic (CFD) model of the fluid flow inside CertainTeed Gypsum's gypsum mixer. Currently, the mixer outputs locally

  17. Thermal Performance of Phase Change Wallboard for Residential Cooling Application

    E-Print Network [OSTI]

    Feustel, H.E.

    2011-01-01T23:59:59.000Z

    implemented in gypsum board, plaster or other wall-coveringimbedded in gypsum board, plaster or other wall-covering7 billion square meters of plaster board are being produced

  18. EFFECT OF GYPSUM ON AVAILABLE PHOSPHORUS EVALUATED BY MEHLICH-1, ION EXCHANGE RESIN, AND Pi-PAPER IN A BRAZILIAN TROPICAL OXISOL

    E-Print Network [OSTI]

    Silva, Rodrigo Coqui da; Chien, Sen Hsuing; Prochnow, Lus Igncio

    2009-01-01T23:59:59.000Z

    Pure gypsum Source average Phosphate Rock (100 mg kg -1 P)Pure gypsum Source average Phosphate Rock (100 mg kg -1 P) bPure gypsum Source average Phosphate Rock (100 mg kg -1 P)

  19. Z .Geoderma 96 2000 4761 The terminology and the concepts of gypsum-rich

    E-Print Network [OSTI]

    Ahmad, Sajjad

    earth-surface processes. q 2000 Elsevier Science B.V. All rights reserved. Keywords: gypsum; gypsiferous of soils and surficial formations containing gypsum is rarely considered in the global environmental December 1999 Abstract Many terms in earth sciences, and their underlying ideas, have been developed

  20. Oxidation of North Dakota scrubber sludge for soil amendment and production of gypsum. Final report

    SciTech Connect (OSTI)

    Hassett, D.J.; Moe, T.A.

    1997-10-01T23:59:59.000Z

    Cooperative Power`s Coal Creek Station (CCS) the North Dakota Industrial Commission, and the US Department of Energy provided funds for a research project at the Energy and Environmental Research Center. The goals of the project were (1) to determine conditions for the conversion of scrubber sludge to gypsum simulating an ex situ process on the laboratory scale; (2) to determine the feasibility of scaleup of the process; (3) if warranted, to demonstrate the ex situ process for conversion on the pilot scale; and (4) to evaluate the quality and handling characteristics of the gypsum produced on the pilot scale. The process development and demonstration phases of this project were successfully completed focusing on ex situ oxidation using air at low pH. The potential to produce a high-purity gypsum on a commercial scale is excellent. The results of this project demonstrate the feasibility of converting CCS scrubber sludge to gypsum exhibiting characteristics appropriate for agricultural application as soil amendment as well as for use in gypsum wallboard production. Gypsum of a purity of over 98% containing acceptable levels of potentially problematic constituents was produced in the laboratory and in a pilot-scale demonstration.

  1. GyPSuM: A Detailed Tomographic Model of Mantle Density and Seismic Wave Speeds

    SciTech Connect (OSTI)

    Simmons, N A; Forte, A M; Boschi, L; Grand, S P

    2010-03-30T23:59:59.000Z

    GyPSuM is a tomographic model fo mantle seismic shear wave (S) speeds, compressional wave (P) speeds and detailed density anomalies that drive mantle flow. the model is developed through simultaneous inversion of seismic body wave travel times (P and S) and geodynamic observations while considering realistic mineral physics parameters linking the relative behavior of mantle properties (wave speeds and density). Geodynamic observations include the (up to degree 16) global free-air gravity field, divergence of the tectonic plates, dynamic topography of the free surface, and the flow-induced excess ellipticity of the core-mantle boundary. GyPSuM is built with the philosophy that heterogeneity that most closely resembles thermal variations is the simplest possible solution. Models of the density field from Earth's free oscillations have provided great insight into the density configuration of the mantle; but are limited to very long-wavelength solutions. Alternatively, simply scaling higher resolution seismic images to density anomalies generates density fields that do not satisfy geodynamic observations. The current study provides detailed density structures in the mantle while directly satisfying geodynamic observations through a joint seismic-geodynamic inversion process. Notable density field observations include high-density piles at the base of the superplume structures, supporting the fundamental results of past normal mode studies. However, these features are more localized and lower amplitude than past studies would suggest. When we consider all seismic anomalies in GyPSuM, we find that P and S-wave speeds are strongly correlated throughout the mantle. However, correlations between the high-velocity S zones in the deep mantle ({approx} 2000 km depth) and corresponding P-wave anomalies are very low suggesting a systematic divergence from simplified thermal effects in ancient subducted slab anomalies. Nevertheless, they argue that temperature variations are the primary cause of P-wave, S-wave, and density anomalies in the mantle.

  2. Field dependent emission rates in radiation damaged GaAs

    SciTech Connect (OSTI)

    Fleming, R. M.; Myers, S. M.; Wampler, W. R.; Lang, D. V.; Seager, C. H.; Campbell, J. M. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1415 (United States)

    2014-07-07T23:59:59.000Z

    We have measured the temperature and field dependence of emission rates from five traps in electron damaged GaAs. Four of the traps have previously been identified as radiation defects. One of the traps, seen in higher doped diodes, has not been previously identified. We have fit the data to a multiphonon emission theory that allows recombination in GaAs to be characterized over a broad range of temperature and electric field. These results demonstrate an efficient method to calculate field-dependent emission rates in GaAs.

  3. Accurate characterization and improvement of GaAs microstrip attenuation

    E-Print Network [OSTI]

    Carroll, James Mason

    2012-06-07T23:59:59.000Z

    Convergence. III. E. 6 Final Model. III. F Simulation Results for 100 um GaAs. . III. F. 1 On-GaAs Microstrip. III. I', 2 Suspended Microstrip Line . . . . 50 . . . . 51 . . . . 54 . . . . 56 . . . . 56 . . . 56 . . . . 64 64 . . . , 64 III. F. 3... Comparison Between On-GaAs and Suspcndcd Microstrip . . . 68 III. F. 4 Microstrip Inductance III. G EM Parameters in CAD Simulations . . III. H Simulation Results for 150 um GaAs. III. I Conclusions and Recommendations. IV RESEARCH ACCOMPLISHMENTS...

  4. The use of gypsum and a coal desulfurization by-product to ameliorate subsoil acidity for alfalfa growth

    E-Print Network [OSTI]

    Chessman, Dennis John

    2004-09-30T23:59:59.000Z

    that used 0, 5, and 10 Mg ha-1 of gypsum only. Field studies were concluded 41 and 45 months after treatment application at the two locations. No effect of material on alfalfa yield or tissue mineral concentration was observed. Also, rate did not affect...

  5. TESLA-FEL 2007-03 Application of low cost GaAs LED as neutron

    E-Print Network [OSTI]

    neutrons in unbiased Gallium Arsenide (GaAs) Light Emitting Diodes (LED) resulted in a reduction Keywords: COTS components, Displacement damage, Electron Linear Accelerator, GaAs Light emitting diode (LED) Gallium Arsenide (GaAs) light emitting diode (LED) for the assessment of integrated neutron fluence

  6. Simple intrinsic defects in GaAs : numerical supplement.

    SciTech Connect (OSTI)

    Schultz, Peter Andrew

    2012-04-01T23:59:59.000Z

    This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory calculations of properties of simple intrinsic defects in gallium arsenide are presented.

  7. Ga nanoparticle-enhanced photoluminescence of GaAs

    SciTech Connect (OSTI)

    Kang, M.; Al-Heji, A. A.; Jeon, S.; Wu, J. H. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Lee, J.-E.; Saucer, T. W.; Zhao, L.; Sih, V. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States); Katzenstein, A. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Eckerd College, St. Petersburg, Florida 33711-4744 (United States); Sofferman, D. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Adelphi University, Garden City, New York 11530-0701 (United States); Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

    2013-09-02T23:59:59.000Z

    We have examined the influence of surface Ga nanoparticles (NPs) on the enhancement of GaAs photoluminescence (PL) efficiency. We have utilized off-normal focused-ion-beam irradiation of GaAs surfaces to fabricate close-packed Ga NP arrays. The enhancement in PL efficiency is inversely proportional to the Ga NP diameter. The maximum PL enhancement occurs for the Ga NP diameter predicted to maximize the incident electromagnetic (EM) field enhancement. The PL enhancement is driven by the surface plasmon resonance (SPR)-induced enhancement of the incident EM field which overwhelms the SPR-induced suppression of the light emission.

  8. Gallium Arsenide (GaAs) EDWARD D. PALIK

    E-Print Network [OSTI]

    Pulfrey, David L.

    constants of pure (semi-insulating) GaAs are derived from a number of papers including the far-infrared at. [4]; the near-IR work of Pikhtin and Yas'kov [5]; the calorim- etry work of Christensen et al. [6 reflection work of Philipp and Ehrenreich [9]; and the synchrotron transmission work of Cardona et al. [10

  9. Response of GaAs to fast intense laser pulses

    E-Print Network [OSTI]

    Graves, JS; Allen, Roland E.

    1998-01-01T23:59:59.000Z

    Motivated by recent experiments, we have performed simulations which show in detail how the electrons and ions in GaAs respond to fast intense laser pulses (with durations of order 100 fs and intensities of order 1-10 TW/cm(2)). The method of tight...

  10. Ballistic thermal point contacts made of GaAs nanopillars

    SciTech Connect (OSTI)

    Bartsch, Th.; Wetzel, A.; Sonnenberg, D.; Schmidt, M.; Heyn, Ch.; Hansen, W. [Institut fr Angewandte Physik und Zentrum fr Mikrostrukturforschung, Universitt Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany)

    2013-12-04T23:59:59.000Z

    We measure the thermal conductance of GaAs pillars that are only a few nanometers long. Our observations can be understood with a simple model, in which the pillars constitute thermal point contacts between 3D phonon reservoirs. Moreover, first measurements of the electronic transport through these pillars are presented.

  11. High-quality InP on GaAs

    E-Print Network [OSTI]

    Quitoriano, Nathaniel Joseph

    2006-01-01T23:59:59.000Z

    In addition to traditional telecommunication applications, devices based on InP have received increased attention for high-performance electronics. InP growth on GaAs is motivated by the fact that InP wafers are smaller, ...

  12. Testing a GaAs cathode in SRF gun

    SciTech Connect (OSTI)

    Wang, E.; Kewisch, J.; Ben-Zvi, I.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2011-03-28T23:59:59.000Z

    RF electron guns with a strained superlattice GaAs cathode are expected to generate polarized electron beams of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface and lower cathode temperature. We plan to install a bulk GaAs:Cs in a SRF gun to evaluate the performance of both the gun and the cathode in this environment. The status of this project is: In our 1.3 GHz 1/2 cell SRF gun, the vacuum can be maintained at nearly 10{sup -12} Torr because of cryo-pumping at 2K. With conventional activation of bulk GaAs, we obtained a QE of 10% at 532 nm, with lifetime of more than 3 days in the preparation chamber and have shown that it can survive in transport from the preparation chamber to the gun. The beam line has been assembled and we are exploring the best conditions for baking the cathode under vacuum. We report here the progress of our test of the GaAs cathode in the SRF gun. Future particle accelerators, such as eRHIC and the ILC require high-brightness, high-current polarized electrons. Strained superlattice GaAs:Cs has been shown to be an efficient cathode for producing polarized electrons. Activation of GaAs with Cs,O(F) lowers the electron affinity and makes it energetically possible for all the electrons, excited into the conduction band that drift or diffuse to the emission surface, to escape into the vacuum. Presently, all operating polarized electron sources, such as the CEBAF, are DC guns. In these devices, the excellent ultra-high vacuum extends the lifetime of the cathode. However, the low field gradient on the photocathode's emission surface of the DC guns limits the beam quality. The higher accelerating gradients, possible in the RF guns, generate a far better beam. Until recently, most RF guns operated at room temperature, limiting the vacuum to {approx}10{sup -9} Torr. This destroys the GaAs's NEA surface. The SRF guns combine the excellent vacuum conditions of DC guns and the high accelerating gradient of the RF guns, potentially offering a long lived cathode with very low emittance. Testing this concept requires preparation of the cathode, transportation to the SRF gun and evaluation of the performance of the cathode and the gun at cryogenic temperatures. In our work at BNL, we successfully activated the bulk GaAs in the preparation chamber. The highest quantum efficient was 10% at 532 nm that fell to 0.5% after 100 hours. We explored three different ways to activate the GaAs. We verified that the GaAs photocathode remains stable for 30 hours in a 10{sup -11} Torr vacuum. Passing the photocathode through the low 10{sup -9} Torr transfer section in several seconds caused the QE to drop to 0.8%. The photocathode with 0.8% QE can be tested for the SRF gun. The gun and beam pipe were prepared and assembled. After baking at 200 C baking, the vacuum of the gun and beam pipe can sustain a low 10{sup -11} Torr at room temperature. The final test to extract electrons from the gun is ongoing. In this paper, we discuss our progress with this SRF gun and the results of the photocathode in preparation chamber and in magnet transfer line.

  13. 2=picosecond, GaAs photodiode optoelectronic circuit for optical correlation applications

    E-Print Network [OSTI]

    Ozbay, Ekmel

    2=picosecond, GaAs photodiode optoelectronic circuit for optical correlation applications K. D. Li GaAs Schottky photodiode is monolithically integrated with a microwave detector. By using this new optoelectronic circuit.in place of a nonlinear crystal in an optical correlation setup, the high-speed photodiode

  14. Photorefractive measurements in electron irradiated semi-insulating GaAs

    E-Print Network [OSTI]

    . The native and irradiation induced defects have been assessed by electron paramagnetic resonance and optical irradiation induced defects in GaAs, we present results of electron paramagnetic resonance (EPR) and optical1 Photorefractive measurements in electron irradiated semi-insulating GaAs P. Delaye(1), H.J. von

  15. A study of microstrip T-juction discontinuity effects and modeling on GAAS substrates

    E-Print Network [OSTI]

    Guill, Dennis Jarrett

    2012-06-07T23:59:59.000Z

    . Currently, GaAs T-junction discontinuity effects and circuit models are not fully understood nor accurate. This thesis thoroughly characterizes 100 um thick GaAs based microstrip T-junction discontinuity effects. This thesis also provides a new CAD based...

  16. ORIGINAL ARTICLE Highly efficient GaAs solar cells by limiting light emission

    E-Print Network [OSTI]

    Atwater, Harry

    ORIGINAL ARTICLE Highly efficient GaAs solar cells by limiting light emission angle Emily D Kosten1 solar cell under direct sunlight, light is received from the solar disk, but is re-emitted isotropically.1038/lsa.2013.1; published online 4 January 2013 Keywords: detailed balance; GaAs solar cell; light

  17. Plasmonic nanoparticle enhanced light absorption in GaAs solar cells Keisuke Nakayama,a

    E-Print Network [OSTI]

    Atwater, Harry

    Plasmonic nanoparticle enhanced light absorption in GaAs solar cells Keisuke Nakayama,a Katsuaki 22 September 2008 We demonstrate an improvement in efficiency of optically thin GaAs solar cells-ratio nanoparticles effectively increases the optical path of the incident light in the absorber layers resulting

  18. Free carrier induced spectral shift for GaAs filled metallic hole arrays

    E-Print Network [OSTI]

    New Mexico, University of

    . Soref, and J. A. D. Alamo, "Carrier-induced change in refractive index of InP, GaAs, and InGaAsP," IEEE-photon absorption (3PA) assisted by strongly enhanced local fields, reduce the refractive index of GaAs in ~200-nm thick active area through band filling and free carrier absorption. Therefore, the surface plasma wave

  19. Evolution Of Surface Topography On GaAs(100) And GaAs(111) At Normal And Oblique Incidence Of Ar{sup +}-Ions

    SciTech Connect (OSTI)

    Venugopal, V.; Basu, T.; Garg, S.; Majumder, S.; Sarangi, S. N.; Som, T. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India); Das, P.; Bhattacharyya, S. R.; Chini, T. K. [Surface Physics Division, Saha Institute of Nuclear Physics, Kolkata 700 064 (India)

    2010-10-04T23:59:59.000Z

    Nanoscale surface structures emerging from medium energy (50-60 keV)Ar{sup +}-ion sputtering of p-type GaAs(100) and semi-insulating GaAs(111) substrates have been investigated. For normally incident 50 keV Ar{sup +}-ions of fluence 1x10{sup 17} ions/cm{sup 2} on GaAs(100) and GaAs(111) features in the form of nanoscale pits/holes without short range ordering are observed with densities 5.2x10{sup 9} /cm{sup 2} and 5.9x10{sup 9} /cm{sup 2}, respectively along with irregularly shaped patches of islands. For GaAs(111) on increasing the influence to 5x10{sup 17} /cm{sup 2} the pit density increases marginally to 6.2x10{sup 9} /cm{sup 2}. For 60 deg. off-normal incidence of 60 keV Ar.{sup +}-ions of fluence 2x10{sup 17} ions/cm{sup 2} on GaAs(100) microscale wavelike surface topography is observed. In all cases well-defined nanodots are absent on the surface.

  20. Quantum effects in electron beam pumped GaAs

    SciTech Connect (OSTI)

    Yahia, M. E. [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt) [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Azzouz, I. M. [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt)] [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)] [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)

    2013-08-19T23:59:59.000Z

    Propagation of waves in nano-sized GaAs semiconductor induced by electron beam are investigated. A dispersion relation is derived by using quantum hydrodynamics equations including the electrons and holes quantum recoil effects, exchange-correlation potentials, and degenerate pressures. It is found that the propagating modes are instable and strongly depend on the electron beam parameters, as well as the quantum recoil effects and degenerate pressures. The instability region shrinks with the increase of the semiconductor number density. The instability arises because of the energetic electron beam produces electron-hole pairs, which do not keep in phase with the electrostatic potential arising from the pair plasma.

  1. Back contacted and small form factor GAAS solar cell.

    SciTech Connect (OSTI)

    Clews, Peggy Jane; Wanlass, Mark W. (National Renewable Energy Laboratory); Sanchez, Carlos A.; Pluym, Tammy; Cruz-Campa, Jose Luis; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James

    2010-06-01T23:59:59.000Z

    We present a newly developed microsystem enabled, back-contacted, shade-free GaAs solar cell. Using microsystem tools, we created sturdy 3 {micro}m thick devices with lateral dimensions of 250 {micro}m, 500 {micro}m, 1 mm, and 2 mm. The fabrication procedure and the results of characterization tests are discussed. The highest efficiency cell had a lateral size of 500 {micro}m and a conversion efficiency of 10%, open circuit voltage of 0.9 V and a current density of 14.9 mA/cm{sup 2} under one-sun illumination.

  2. 26. 1% solar cell efficiency for Ge mechanically stacked under GaAs

    SciTech Connect (OSTI)

    Partain, L.D.; Kuryla, M.S.; Weiss, R.E.; Ransom, R.A.; McLeod, P.S.; Fraas, L.M.; Cape, J.A.

    1987-10-01T23:59:59.000Z

    We have processed a diffused Ge wafer into a Ge concentrator solar cell and mechanically stacked it under a GaAs cell fabricated by Varian. We measured this stack's efficiency to be 26.1% for terrestrial air mass 1.5 direct (AM1.5D) conditions at a 285 x concentration ratio. We showed that this efficiency is limited by optical absorption in the Varian GaAs cell caused by high 2--4 (10/sup 18/) cm/sup -3/ substrate doping. We used a 2 x 10/sup 17/ cm/sup -3/ doped GaAs filter to estimate the stack efficiency as 27.4%, which would be achieved with the same Varian GaAs cell formed on a lower doped substrate. We project efficiencies assuming the best properties reported for a GaAs device. This gives a 29.6% efficiency for an improved, planar Ge cell and 31.6% efficiency for a proposed point contact geometry for the Ge cell. The corresponding space (AM0) efficiencies at a 159 x concentration ratio range from the 23.4% value we measured on the stack up to 28.4% projected for the point contact Ge place under the best GaAs cell. We showed that Ge cells give higher efficiencies than Si when stacked under GaAs.

  3. Ambipolar spin diffusion and D'yakonov-Perel' spin relaxation in GaAs quantum wells

    E-Print Network [OSTI]

    Zhao, Hui; Mower, Matt; Vignale, G.

    2009-03-01T23:59:59.000Z

    We report theoretical and experimental studies of ambipolar spin diffusion in a semiconductor. A circularly polarized laser pulse is used to excite spin-polarized carriers in a GaAs multiple quantum-well sample at 80 K. ...

  4. E-Print Network 3.0 - activated gaas surface Sample Search Results

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

    Collection: Materials Science 8 Dissimilar and Nanomaterials for Optoelectronic Devices Summary: ) on GaAs Diluted-N-based QW Sb-based QW (GaInNAsSb) QD-based active...

  5. E-Print Network 3.0 - annealed gaas spectroscopic Sample Search...

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

    annealed epitaxial Ge surface. Fig. 2. RHEED patterns during growth of an APD-free GaAs film... was deposited and annealed for 20 min at either 350, 560, or 640C to observe the...

  6. Electron transfer and capture dynamics in ZnSe quantum wells grown on GaAs

    SciTech Connect (OSTI)

    Dongol, A.; Wagner, H. P. [Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (United States)

    2013-12-04T23:59:59.000Z

    We investigate the transfer and capture dynamics of electrons in phase coherent photorefractive ZnSe quantum wells grown on GaAs using degenerate three-beam four-wave-mixing. The measurements reveal electron capture times by the quantum well in the order of several tens of picoseconds and a transit time of approximately 5 picoseconds from the GaAs substrate through the ZnMgSe barrier.

  7. Defect studies in low-temperature-grown GaAs

    SciTech Connect (OSTI)

    Bliss, D.E.

    1992-11-01T23:59:59.000Z

    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V{sub Ga}. The neutral AsGa-related defects were measured by infrared absorption at 1{mu}m. Gallium vacancies, V{sub Ga}, was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10{sup 19} cm{sup {minus}3} Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As{sub Ga} in the layer. As As{sub Ga} increases, photoquenchable As{sub Ga} decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As{sub Ga} content around 500C, similar to irradiation damaged and plastically deformed Ga{sub As}, as opposed to bulk grown GaAs in which As{sub Ga}-related defects are stable up to 1100C. The lower temperature defect removal is due to V{sub Ga} enhanced diffusion of As{sub Ga} to As precipitates. The supersaturated V{sub GA} and also decreases during annealing. Annealing kinetics for As{sub Ga}-related defects gives 2.0 {plus_minus} 0.3 eV and 1.5 {plus_minus} 0.3 eV migration enthalpies for the As{sub Ga} and V{sub Ga}. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As{sub Ga}-related defects anneal with an activation energy of 1.1 {plus_minus} 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As{sub Ga}-Be{sub Ga} pairs. Si donors can only be partially activated.

  8. Defect studies in low-temperature-grown GaAs

    SciTech Connect (OSTI)

    Bliss, D.E.

    1992-11-01T23:59:59.000Z

    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

  9. GaAs Blocked-Impurity-Band Detectors for Far-Infrared Astronomy

    SciTech Connect (OSTI)

    Cardozo, Benjamin Lewin

    2004-12-21T23:59:59.000Z

    High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 10{sup 13} cm{sup -3}, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing layer of a BIB detector, has been achieved. The control of the donor concentration, however, was found to be insufficient for detector production. The growth by LPE of a high-purity film onto a commercially grown vapor-phase epitaxial (VPE) n-type GaAs doped absorbing layer resulted in a BIB device that showed a significant reduction in the low-temperature dark current compared to the absorbing layer only. Extended optical response was not detected, most likely due to the high compensation of the commercially grown GaAs absorbing layer, which restricts the depletion width of the device.

  10. Metal-insulator-semiconductor structures on p-type GaAs with low interface state density

    E-Print Network [OSTI]

    Chen, Zhi

    Metal-insulator-semiconductor structures on p-type GaAs with low interface state density Zhi Chen properties of in situ deposited Si3N4 /Si/p-GaAs metal-insulator-semiconductor structures have been offered by a low gate leakage technology in GaAs, such as metal insulator structures, func- tional Ga

  11. Orientation of tectonic stresses in central Kentucky during U. Devonian/L. Mississippian times: Evidence from quartz veins (after gypsum) in NE-trending, systematic joints in shales

    SciTech Connect (OSTI)

    Grover, J.; Dupuis-Nouille, E.M. (Univ. of Cincinnati, Cincinnati, OH (United States). Dept. of Geology)

    1992-01-01T23:59:59.000Z

    Quartz replacing fibrous gypsum and anhydrite pseudomorphically (QAS; quartz after sulfate''), and preserving characteristic crack-seal'' and chickenwire'' textures, occurs in extensional veins at four locations in central KY. The veins occupy a systematic set of NE-SW-trending, vertical joints within the essentially flat-lying shales of the Renfro Member of the Mississippian Borden Formation and the Late Devonian New Albany Shale. The four QAS occurrences discovered to date are located northeast of the Borden Front. At one site in the New Albany Shale, QAS veins show clear evidence of penecontemporaneous deformation. It is proposed that at all QAS locations, gypsum precipitated in incipient joints before complete lithification of the sediment, and grew perpendicular to the fractures to form extensional veins in the soft but firm muds. The orientations of the joints now marked by QAS veins are broadly consistent with regional patterns of NE-SW-trending systematic joints and lineaments in southern IN and in central and eastern KY. These systematic fracture patterns do not correspond directly to known basement faults or rift systems, although they are consistent with modern stress directions in eastern and western KY, measured in situ in wells and by earthquake fault-plane solutions. It is proposed that this systematic trend marks the regional tectonic stress pattern characteristic of southern IN and central and eastern KY at, and since the Late Devonian. The evidence of penecontemporaneous sedimentary deformation in joints of U. Devonian age, marked and preserved by quartz replacement of early gypsum, is sufficient to show that while the systematic NE-trending joint set in KY may also be modern it is not uniquely so.

  12. Evolution of ion-induced nanoparticle arrays on GaAs surfaces

    SciTech Connect (OSTI)

    Kang, M.; Al-Heji, A. A.; Shende, O.; Huang, S.; Jeon, S.; Goldman, R. S., E-mail: rsgold@umich.edu [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Beskin, I. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

    2014-05-05T23:59:59.000Z

    We have examined the evolution of irradiation-induced Ga nanoparticle (NP) arrays on GaAs surfaces. Focused-ion-beam irradiation of pre-patterned GaAs surfaces induces monotonic increases in the NP volume and aspect ratio up to a saturation ion dose, independent of NP location within the array. Beyond the saturation ion dose, the NP volume continues to increase monotonically while the NP aspect ratio decreases monotonically. In addition, the NP volumes (aspect ratios) are highest (lowest) for the corner NPs. We discuss the relative influences of bulk and surface diffusion on the evolution of Ga NP arrays.

  13. Second harmonic generation in photonic crystal cavities in (111)-oriented GaAs

    SciTech Connect (OSTI)

    Buckley, Sonia, E-mail: bucklesm@stanford.edu; Radulaski, Marina; Vu?kovi?, Jelena [E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States)] [E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States); Biermann, Klaus [Paul-Drude-Institut fr Festkrperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)] [Paul-Drude-Institut fr Festkrperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)

    2013-11-18T23:59:59.000Z

    We demonstrate second harmonic generation at telecommunications wavelengths in photonic crystal cavities in (111)-oriented GaAs. We fabricate 30 photonic crystal structures in both (111)- and (100)-oriented GaAs and observe an increase in generated second harmonic power in the (111) orientation, with the mean power increased by a factor of 3, although there is a large scatter in the measured values. We discuss possible reasons for this increase, in particular, the reduced two photon absorption for transverse electric modes in (111) orientation, as well as a potential increase due to improved mode overlap.

  14. Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs

    SciTech Connect (OSTI)

    Takamiya, Kengo; Fukushima, Toshiyuki; Yagi, Shuhei; Hijikata, Yasuto; Yaguchi, Hiroyuki [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku , Saitama 338-8570 (Japan); Mochizuki, Toshimitsu; Yoshita, Masahiro; Akiyama, Hidefumi [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Kuboya, Shigeyuki; Onabe, Kentaro [Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Katayama, Ryuji [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2013-12-04T23:59:59.000Z

    We have studied photoluminescence (PL) from individual isoelectronic traps formed by nitrogen-nitrogen (NN) pairs in GaAs. Sharp emission lines due to exciton and biexciton were observed from individual isoelectronic traps in nitrogen atomic-layer doped (ALD) GaAs. The binding energy of biexciton bound to individual isoelectronic traps was approximately 8 meV. Both the exciton and biexciton luminescence lines show completely random polarization and no fine-structure splitting. These results are desirable to the application to the quantum cryptography used in the field of quantum information technology.

  15. Near perfect solar absorption in ultra-thin-film GaAs photonic crystals

    E-Print Network [OSTI]

    John, Sajeev

    Near perfect solar absorption in ultra-thin-film GaAs photonic crystals Sergey Eyderman,*a Alexei Deinegaa and Sajeev Johnab We present designs that enable a significant increase of solar absorption­99.5% solar absorption is demonstrated depending on the photonic crystal architecture used and the nature

  16. GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies

    E-Print Network [OSTI]

    Rogers, John A.

    LETTERS GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies-frequency electronics3,4 and most forms of optoelectronics5,6 . However, growing large, high quality wafers implementation. More tractable, yet still difficult, problems appear in advanced electronics and optoelectronics

  17. Dynamics of Subsurface and Surface Chemisorption for B, C, and N on Gaas and Inp

    E-Print Network [OSTI]

    MENON, M.; Allen, Roland E.

    1991-01-01T23:59:59.000Z

    on GaAs. H=HO+ V, @11 0 0 0 (2.7) (2.8) The Green's function for this system is G =(el ?H ) (2.9) Let H be the 1V XX Hamiltonian matrix for a large sys- tem (N~ ~ here). We suppose that H differs from an unperturbed Hamiltonian Ho only in some...

  18. SSL/TLS Session-Aware User Authentication Using a GAA Bootstrapped Key

    E-Print Network [OSTI]

    Sheldon, Nathan D.

    SSL/TLS Session-Aware User Authentication Using a GAA Bootstrapped Key Chunhua Chen1 , Chris J.mitchell@rhul.ac.uk Abstract. Most SSL/TLS-based electronic commerce (e-commerce) ap- plications (including Internet banking a server effectively, and because user authentication methods are typi- cally decoupled from SSL

  19. Experimental demonstration of enhanced photon recycling in angle-restricted GaAs solar cells

    E-Print Network [OSTI]

    Faraon, Andrei

    Experimental demonstration of enhanced photon recycling in angle-restricted GaAs solar cells Emily, emphasizing the optical nature of the effect. 1 Introduction For ideal solar cells where all recombination. Despite this theoretical prediction, until recently even the highest efficiency solar cells were not close

  20. Surface science analysis of GaAs photocathodes following sustained electron beam delivery

    SciTech Connect (OSTI)

    Carlos Hernandez-Garcia, Fay Hannon, Marcy Stutzman, V. Shutthanandan, Z. Zhu, M. Nandasri, S. V. Kuchibhatla, S. Thevuthasan, W. P. Hess

    2012-06-01T23:59:59.000Z

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Photocathode quantum efficiency (QE) degradation is due to residual gasses in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector and one unused, were also analyzed using Transmission Electron Microscopy (TEM) and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but shows evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

  1. Femtosecond-scale response of GaAs to ultrafast laser pulses RID A-7793-2008

    E-Print Network [OSTI]

    Dumitrica, T.; Allen, Roland E.

    2002-01-01T23:59:59.000Z

    We present nonadiabatic simulations of the coherent response of crystalline GaAs irradiated by intense femtosecond-scale laser pulses. Above a threshold fluence, which corresponds to promotion of about 12% of the valence electrons...

  2. Nanometer-scale GaAs clusters from organometallic precursors Peter C. Sercel, Winston A. Saunders, Harry A. Atwater,

    E-Print Network [OSTI]

    Atwater, Harry

    the first direct observation of gas-phase ho- mogeneous nucleation of GaAs by the thermophoretic col thermophoret- ically on a holey carbon film which is mounted on a stain- less steel fixture aligned coaxially

  3. Fabrication of wideband optoelectronic differential amplifier using a balanced receiver on a semi-insulating GaAs substrate

    E-Print Network [OSTI]

    Choi, Kyoo Nam

    1989-01-01T23:59:59.000Z

    FABRICATION OF WIDEBAND OPTOELECTRONIC DIFFERENTIAL AMPLIFIER USING A BALANCED RECEIVER ON A SEMI-INSULATING GAAS SUBSTRATE A Thesis by KYOO NAM CHOI Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1989 Major Subject: Electrical Engineering FABRICATION Ol' WIDEBAND OPTOELECTRONIC DIFFERENTIAL A1VIPLIFIER USING A BAI, ANCED RECEIVER ON A SEMI. INSULATING GAAS SUBSTRATE A Thesis by l(YOO NAM...

  4. A near-infrared photoluminescence study of GaAs nanocrystals in SiO2 films formed by sequential ion implantation

    E-Print Network [OSTI]

    Atwater, Harry

    A near-infrared photoluminescence study of GaAs nanocrystals in SiO2 films formed by sequential ion GaAs nanocrystals are formed in SiO2 films and several PL bands appear in the red and near-infrared spectral region. Defects and impurities in GaAs nanocrystals and SiO2 cause weak luminescence in the near-infrared

  5. Effects of atomic hydrogen and deuterium exposure on high polarization GaAs photocathodes

    SciTech Connect (OSTI)

    M. Baylac; P. Adderley; J. Brittian; J. Clark; T. Day; J. Grames; J. Hansknecht; M. Poelker; M. Stutzman; A. T. Wu; A. S. Terekhov

    2005-12-01T23:59:59.000Z

    Strained-layer GaAs and strained-superlattice GaAs photocathodes are used at Jefferson Laboratory to create high average current beams of highly spin-polarized electrons. High electron yield, or quantum efficiency (QE), is obtained only when the photocathode surface is atomically clean. For years, exposure to atomic hydrogen or deuterium has been the photocathode cleaning technique employed at Jefferson Laboratory. This work demonstrates that atomic hydrogen cleaning is not necessary when precautions are taken to ensure that clean photocathode material from the vendor is not inadvertently dirtied while samples are prepared for installation inside photoemission guns. Moreover, this work demonstrates that QE and beam polarization can be significantly reduced when clean high-polarization photocathode material is exposed to atomic hydrogen from an rf dissociator-style atomic hydrogen source. Surface analysis provides some insight into the mechanisms that degrade QE and polarization due to atomic hydrogen cleaning.

  6. Growth and properties of crystalline barium oxide on the GaAs(100) substrate

    SciTech Connect (OSTI)

    Yasir, M.; Dahl, J.; Lng, J.; Tuominen, M.; Punkkinen, M. P. J.; Laukkanen, P., E-mail: pekka.laukkanen@utu.fi; Kokko, K. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)] [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Kuzmin, M. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland) [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Korpijrvi, V.-M.; Polojrvi, V.; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland)] [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland)

    2013-11-04T23:59:59.000Z

    Growing a crystalline oxide film on III-V semiconductor renders possible approaches to improve operation of electronics and optoelectronics heterostructures such as oxide/semiconductor junctions for transistors and window layers for solar cells. We demonstrate the growth of crystalline barium oxide (BaO) on GaAs(100) at low temperatures, even down to room temperature. Photoluminescence (PL) measurements reveal that the amount of interface defects is reduced for BaO/GaAs, compared to Al{sub 2}O{sub 3}/GaAs, suggesting that BaO is a useful buffer layer to passivate the surface of the III-V device material. PL and photoemission data show that the produced junction tolerates the post heating around 600?C.

  7. Cavity nucleation and evolution in He-implanted Si and GaAs

    SciTech Connect (OSTI)

    Follstaedt, D.M.; Myers, S.M.; Petersen, G.A.; Barbour, J.C.

    1995-12-01T23:59:59.000Z

    The criteria for forming stable cavities by He{sup +} implantation and annealing are examined for Si and GaAs. In Si, implanting at room temperature requires a minimum of 1.6 at. % He to form a continuous layer of cavities after annealing at 700{degrees}C. The cavities are located at dislocations and planar defects. Implanting peak He concentrations just above this threshold produces narrow layers of cavities at the projected range. In GaAs, room-temperature implantation followed by annealing results in exfoliation of the surface layer. Cavities were formed instead by implanting Ar followed by overlapping He, both at 400{degrees}C, with additional annealing at 400{degrees}C to outgas the He. This method forms 1.5--3.5 nm cavities that are often on [111] planar defects.

  8. Gallium surface diffusion on GaAs (001) surfaces measured by crystallization dynamics of Ga droplets

    SciTech Connect (OSTI)

    Bietti, Sergio, E-mail: sergio.bietti@mater.unimib.it; Somaschini, Claudio; Esposito, Luca; Sanguinetti, Stefano [LNESS and Dipartimento di Scienza dei Materiali, Universit di Milano Bicocca, Via Cozzi 55, I20125 Milano (Italy); Fedorov, Alexey [LNESS and CNRIFN, via Anzani 42, I-22100 Como (Italy)

    2014-09-21T23:59:59.000Z

    We present accurate measurements of Ga cation surface diffusion on GaAs surfaces. The measurement method relies on atomic force microscopy measurement of the morphology of nanodisks that evolve, under group V supply, from nanoscale group III droplets, earlier deposited on the substrate surface. The dependence of the radius of such nano-droplets on crystallization conditions gives direct access to Ga diffusion length. We found an activation energy for Ga on GaAs(001) diffusion E{sub A}=1.310.15 eV, a diffusivity prefactor of D{sub 0}?=?0.53(2.11) cm{sup 2} s{sup ?1} that we compare with the values present in literature. The obtained results permit to better understand the fundamental physics governing the motion of group III adatoms on IIIV crystal surfaces and the fabrication of designable nanostructures.

  9. Epitaxial two-dimensional nitrogen atomic sheet in GaAs

    SciTech Connect (OSTI)

    Harada, Yukihiro, E-mail: y.harada@eedept.kobe-u.ac.jp; Yamamoto, Masuki; Baba, Takeshi; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-01-27T23:59:59.000Z

    We have grown an epitaxial two-dimensional nitrogen (N) atomic sheet in GaAs by using the site-controlled N ?-doping technique. We observed a change of the electronic states in N ?-doped GaAs from the isolated impurity centers to the delocalized impurity band at 1.49?eV with increasing N-doping density. According to the excitation-power- and temperature-dependent photoluminescence (PL) spectra, the emission related to localized levels below the impurity band edge was dominant at low excitation power and temperature, whereas the effects of the localized levels can be neglected by increasing the excitation power and temperature. Furthermore, a clear Landau shift of the PL-peak energy was observed at several Tesla in the Faraday configuration, in contrast to the case in the impurity limit.

  10. Design and realization of a GaAs FET integrated with a heterojunction photodiode

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1595 Design and realization of a GaAs FET integrated with a heterojunction photodiode F. Therez, M, accepté le 6 juillet 1987) Résumé. 2014 L'association d'une photodiode à hétérojonction et d'un circuit circuits intégrant l'amplificateur et la photodiode. Les divers dispositifs sont caractérisés et analysés

  11. Molecular Beam Epitaxial Growth of GaAs on (631) Oriented Substrates

    SciTech Connect (OSTI)

    Cruz Hernandez, Esteban; Rojas Ramirez, Juan-Salvador; Contreras Hernandez, Rocio; Lopez Lopez, Maximo [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, Mexico D.F., 07000 (Mexico); Pulzara Mora, Alvaro [Universidad Nacional de Colombia - Sede Manizales, A. A. 127 (Colombia); Mendez Garcia, Victor H. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Av. Karakorum 1470, Lomas 4a Seccion, C.P. 78210, San Luis Potosi (Mexico)

    2007-02-09T23:59:59.000Z

    In this work, we report the study of the homoepitaxial growth of GaAs on (631) oriented substrates by molecular beam epitaxy (MBE). We observed the spontaneous formation of a high density of large scale features on the surface. The hilly like features are elongated towards the [-5, 9, 3] direction. We show the dependence of these structures with the growth conditions and we present the possibility of to create quantum wires structures on this surface.

  12. Identification of As-vacancy complexes in Zn-diffused GaAs

    SciTech Connect (OSTI)

    Elsayed, M. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Department of Physics, Faculty of Science, Minia University, 61519 Minia (Egypt); Krause-Rehberg, R. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Korff, B. [Bremen Center for Computational Materials Science, University Bremen, 28359 Bremen (Germany); Richter, S. [Fraunhofer Center for Silicon Photovoltaics CSP, 06120 Halle (Saale) (Germany); Leipner, H. S. [Center of Materials Science, Martin Luther University Halle, 06099 Halle (Germany)

    2013-03-07T23:59:59.000Z

    We have used positron annihilation spectroscopy to study the introduction of point defects in Zn-diffused semi-insulating GaAs. The diffusion was performed by annealing the samples for 2 h at 950 Degree-Sign C. The samples were etched in steps of 7 {mu}m. Both Doppler broadening using slow positron beam and lifetime spectroscopy studies were performed after each etching step. Both techniques showed the existence of vacancy-type defects in a layer of about 45 {mu}m. Secondary ion mass spectroscopy measurements illustrated the presence of Zn at high level in the sample almost up to the same depth. Vacancy-like defects as well as shallow positron traps were observed by lifetime measurements. We distinguish two kinds of defects: As vacancy belongs to defect complex, bound to most likely one Zn atom incorporated on Ga sublattice, and negative-ion-type positron traps. Zn acceptors explained the observation of shallow traps. The effect of Zn was evidenced by probing GaAs samples annealed under similar conditions but without Zn treatment. A defect-free bulk lifetime value is detected in this sample. Moreover, our positron annihilation spectroscopy measurements demonstrate that Zn diffusion in GaAs system is governed by kick-out mechanism.

  13. Final report on LDRD project 105967 : exploring the increase in GaAs photodiode responsivity with increased neutron fluence.

    SciTech Connect (OSTI)

    Blansett, Ethan L.; Geib, Kent Martin; Cich, Michael Joseph; Wrobel, Theodore Frank; Peake, Gregory Merwin; Fleming, Robert M.; Serkland, Darwin Keith; Wrobel, Diana L.

    2008-01-01T23:59:59.000Z

    A previous LDRD studying radiation hardened optoelectronic components for space-based applications led to the result that increased neutron irradiation from a fast-burst reactor caused increased responsivity in GaAs photodiodes up to a total fluence of 4.4 x 10{sup 13} neutrons/cm{sup 2} (1 MeV Eq., Si). The silicon photodiodes experienced significant degradation. Scientific literature shows that neutrons can both cause defects as well as potentially remove defects in an annealing-like process in GaAs. Though there has been some modeling that suggests how fabrication and radiation-induced defects can migrate to surfaces and interfaces in GaAs and lead to an ordering effect, it is important to consider how these processes affect the performance of devices, such as the basic GaAs p-i-n photodiode. In this LDRD, we manufactured GaAs photodiodes at the MESA facility, irradiated them with electrons and neutrons at the White Sands Missile Range Linac and Fast Burst Reactor, and performed measurements to show the effect of irradiation on dark current, responsivity and high-speed bandwidth.

  14. Direct determination of exact charge states of surface point defects using scanning tunneling microscopy: As vacancies on GaAs ,,110...

    E-Print Network [OSTI]

    microscopy: As vacancies on GaAs ,,110... Kuo-Jen Chao, Arthur R. Smith, and Chih-Kang Shih* Department of the charge state of surface As vacancies on p-type GaAs 110 using scanning tunneling microscopy. This method utilizes the compensation between the local band bending result- ing from the As vacancy and the p

  15. GaAs single quantum dot embedded into AlGaAs nanowire

    SciTech Connect (OSTI)

    Kochereshko, V. P.; Kats, V. N. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia and Spin Optics Laboratory, Saint Petersburg State University, Ul'yanovskaya 1, Petrodvorets, St. Petersburg, 198904 (Russian Federation); Platonov, A. V. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg (Russian Federation); Cirlin, G. E.; Bouravleuv, A. D.; Samsonenko, Yu. B. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia and St. Petersburg Academic University of the RAS Khlopina 8/3, 195220, St. Petersburg (Russian Federation); Besombes, L.; Mariette, H. [CEA-CNRS group Nanophysique et Semiconducteurs, CEA, INAC, SP2M, and Institut Nel, 17 rue des Martyrs, F-38054 Grenoble (France)

    2013-12-04T23:59:59.000Z

    We report on a study of the photoluminescence spectra taken from quasi one-dimensional and quasi zero-dimensional semiconductor heterostructures. The structures were grown by molecular-beam epitaxy in (111) direction and were cylindrical nanowires based on AlGaAs, of 20 - 50 nm in diameter and 0.5 - 1 ?m in length. Inside the nanowires contain one or two GaAs quantum dots, of 2 nm thick and 15 - 45 nm in diameter. We studied a single nanowire. The photoluminescence and photoluminescence excitation spectra were registered as a function of the intensity of optical excitation.

  16. Nucleation and Growth of GaN on GaAs (001) Substrates

    SciTech Connect (OSTI)

    Drummond, Timothy J.; Hafich, Michael J.; Heller, Edwin J.; Lee, Stephen R.; Liliental-Weber, Zuzanna; Ruvimov, Sergei; Sullivan, John P.

    1999-05-03T23:59:59.000Z

    The nucleation of GaN thin films on GaAs is investigated for growth at 620 "C. An rf plasma cell is used to generate chemically active nitrogen from N2. An arsenic flux is used in the first eight monolayer of nitride growth to enhance nucleation of the cubic phase. Subsequent growth does not require an As flux to preserve the cubic phase. The nucleation of smooth interfaces and GaN films with low stacking fault densities is dependent upon relative concentrations of active nitrogen species in the plasma and on the nitrogen to gallium flux ratio.

  17. Optoelectronic simulation of GaAs solar cells with angularly selective filters

    SciTech Connect (OSTI)

    Kraus, Tobias, E-mail: tobias.kraus@ise.fraunhofer.de; Hhn, Oliver; Hauser, Hubert; Blsi, Benedikt [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany)

    2014-02-07T23:59:59.000Z

    We discuss the influence of angularly selective filters on thin film gallium arsenide solar cells. For this reason, the detailed balance model was refined to fit our needs with respect to Auger recombination, reflection, transmission, and realistic absorption. For calculating real systems, an approach was made to include optical effects of angularly selective filters into electron-hole dynamic equations implemented in PC1D, a one dimensional solar cell calculation tool. With this approach, we find a relative V{sub oc} increase of 5% for an idealized 100?nm GaAs cell, including Auger recombination.

  18. Picosecond buildup and relaxation of intense stimulated emission in GaAs

    SciTech Connect (OSTI)

    Ageeva, N. N.; Bronevoi, I. L., E-mail: bil@cplire.ru; Zabegaev, D. N.; Krivonosov, A. N. [Russian Academy of Sciences, Kotelnikov Institute of Radio Engineering and Electronics (Russian Federation)

    2013-04-15T23:59:59.000Z

    In support of the idea developed previously based on circumstantial evidence, we have found that stimulated emission emerges in GaAs and its intensity increases with a picosecond delay relative to the front of powerful picosecond optical pumping that produced a dense electron-hole plasma. The emission intensity relaxes with decreasing pumping with a characteristic time of {approx}10 ps. We have derived the dependences of the delay time, the relaxation time, and the duration of the picosecond emission pulse on its photon energy. The estimates based on the fact that the relaxation of emission is determined by electron-hole plasma cooling correspond to the measured relaxation time.

  19. Back-contacted and small form factor GaAs solar cell.

    SciTech Connect (OSTI)

    Clews, Peggy Jane; Wanlass, Mark W. (National Renewable Energy Laboratory, Golden, CO); Sanchez, Carlos A.; Pluym, Tammy; Cruz-Campa, Jose Luis; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James

    2010-07-01T23:59:59.000Z

    We present a newly developed microsystem enabled, back-contacted, shade-free GaAs solar cell. Using microsystem tools, we created sturdy 3 {micro}m thick devices with lateral dimensions of 250 {micro}m, 500 {micro}m, 1 mm, and 2 mm. The fabrication procedure and the results of characterization tests are discussed. The highest efficiency cell had a lateral size of 500 {micro}m and a conversion efficiency of 10%, open circuit voltage of 0.9 V and a current density of 14.9 mA/cm{sup 2} under one-sun illumination.

  20. Origins of ion irradiation-induced Ga nanoparticle motion on GaAs surfaces

    SciTech Connect (OSTI)

    Kang, M.; Wu, J. H.; Chen, H. Y.; Thornton, K.; Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Sofferman, D. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Adelphi University, Garden City, New York 11530-0701 (United States); Beskin, I. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

    2013-08-12T23:59:59.000Z

    We have examined the origins of ion irradiation-induced nanoparticle (NP) motion. Focused-ion-beam irradiation of GaAs surfaces induces random walks of Ga NPs, which are biased in the direction opposite to that of ion beam scanning. Although the instantaneous NP velocities are constant, the NP drift velocities are dependent on the off-normal irradiation angle, likely due to a difference in surface non-stoichiometry induced by the irradiation angle dependence of the sputtering yield. It is hypothesized that the random walks are initiated by ion irradiation-induced thermal fluctuations, with biasing driven by anisotropic mass transport.

  1. Ultrafast magneto-photocurrents in GaAs: Separation of surface and bulk contributions

    E-Print Network [OSTI]

    Schmidt, Christian B; Tarasenko, Sergey A; Bieler, Mark

    2015-01-01T23:59:59.000Z

    We induce ultrafast magneto-photocurrents in a GaAs crystal employing interband excitation with femtosecond laser pulses at room temperature and non-invasively separate surface and bulk contributions to the overall current response. The separation between the different symmetry contributions is achieved by measuring the simultaneously emitted terahertz radiation for different sample orientations. Excitation intensity and photon energy dependences of the magneto-photocurrents for linearly and circularly polarized excitations reveal an involvement of different microscopic origins, one of which we believe is the inverse Spin-Hall effect. Our experiments are important for a better understanding of the complex momentum-space carrier dynamics in magnetic fields.

  2. Waveguide effect of GaAsSb quantum wells in a laser structure based on GaAs

    SciTech Connect (OSTI)

    Aleshkin, V. Ya. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Afonenko, A. A. [Belarussian State University (Belarus)] [Belarussian State University (Belarus); Dikareva, N. V. [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)] [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation); Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru; Kudryavtsev, K. E.; Morozov, S. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Nekorkin, S. M. [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)] [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)

    2013-11-15T23:59:59.000Z

    The waveguide effect of GaAsSb quantum wells in a semiconductor-laser structure based on GaAs is studied theoretically and experimentally. It is shown that quantum wells themselves can be used as waveguide layers in the laser structure. As the excitation-power density attains a value of 2 kW/cm{sup 2} at liquid-nitrogen temperature, superluminescence at the wavelength corresponding to the optical transition in bulk GaAs (at 835 nm) is observed.

  3. A Single Layer of Mn in a GaAs Quantum Well: A Ferromagnet with Quantum Fluctuations

    SciTech Connect (OSTI)

    Melko, Roger G [ORNL; Fishman, Randy Scott [ORNL; Reboredo, Fernando A [ORNL

    2007-01-01T23:59:59.000Z

    Some of the highest transition temperatures achieved for Mn-doped GaAs have been in &-doped heterostructures with well-separated planes of Mn. But in the absense of magnetic anisotropy, the Mermin-Wagner theorem implies that a single plane of magnetic ions cannot be ferromagnetic. We show that the same mechanism that produces magnetic frustration and suppresses the transition can stabilize ferromagnetic order for a single layer of Mn in a GaAs quantum well. But this comes at the price of quantum fluctuations that suppress the ordered moment from that of a fully saturated ferromagnet.

  4. Bistability of self-modulation of the GaAs intrinsic stimulated picosecond radiation spectrum

    SciTech Connect (OSTI)

    Ageeva, N. N.; Bronevoi, I. L., E-mail: bil@cplire.ru; Zabegaev, D. N.; Krivonosov, A. N. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)] [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)

    2013-08-15T23:59:59.000Z

    The bistability of self-modulation of the spectrum of the stimulated picosecond radiation that appears during picosecond optical pumping of GaAs is detected. The radiation is measured before it reaches the end faces of a sample. One set of equidistant modes occurs in the radiation spectrum at the radiation pulse front. A set of modes located at the center between the initial modes replaces the first set in the descending radiation branch. The intermode interval inside each set coincides with the calculated interval between the eigenmodes of the GaAs layer, which is an active cavity. The radiation rise time turns out to be an oscillating function of the photon energy. The spectrum evolution is self-consistent so that the time-integrated spectrum and the spectrum-integrated radiation pulse envelope have a smooth (without local singularities) shape. The revealed bistability explains the physical nature of the two radiation-induced states of population depletion between which subterahertz self-oscillations in the radiation field were detected earlier. The radiation spectrum self-modulation is assumed to be a variant of stimulated Raman scattering.

  5. Surface Science Analysis of GaAs Photocathodes Following Sustained Electron Beam Delivery

    SciTech Connect (OSTI)

    Shutthanandan, V.; Zhu, Zihua; Stutzman, Marcy L.; Hannon, Fay; Hernandez-Garcia, Carlos; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai; Hess, Wayne P.

    2012-06-12T23:59:59.000Z

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Several photocathode degradation processes are suspected, including defect formation by ion back bombardment, photochemistry of surface adsorbed species and irradiation-induced surface defect formation. To better understand the mechanisms of photocathode degradation, we have conducted surface and bulk analysis studies of two GaAs photocathodes removed from the FEL photoinjector after delivering electron beam for a few years. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, strained super-lattice GaAs photocathode samples, removed from the CEBAF photoinjector were analyzed using Transmission Electron Microscopy (TEM) and SIMS. This analysis of photocathode degradation during nominal photoinjector operating conditions represents first steps towards developing robust new photocathode designs necessary for generating sub-micron emittance electron beams required for both fourth generation light sources and intense polarized CW electron beams for nuclear and high energy physics facilities.

  6. THIN FILM SOLAR CELLS AND A REVIEW OF RECENT RESULTS ON GaAs By PAUL RAPPAPORT,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    154. THIN FILM SOLAR CELLS AND A REVIEW OF RECENT RESULTS ON GaAs By PAUL RAPPAPORT, RCA been known that non-single- crystals films can be used for solar cells as, for example, in the selenium and copper oxide photo- electric exposnre meter. More recently [1], the cadmium sulfide film-type solar cell

  7. All-optical generation and detection of subpicosecond ac spin-current pulses in GaAs

    E-Print Network [OSTI]

    Ruzicka, Brian Andrew; Higley, Karl; Werake, Lalani Kumari; Zhao, Hui

    2008-07-01T23:59:59.000Z

    Subpicosecond ac spin-current pulses are generated optically in GaAs bulk and quantum wells at room temperature and at 90 K through quantum interference between one-photon and two-photon absorptions driven by two phase-locked ...

  8. Diffusion of a Ga adatom on the GaAs(001)c(44)heterodimer surface: A first principles study

    E-Print Network [OSTI]

    Khare, Sanjay V.

    Diffusion of a Ga adatom on the GaAs(001)c(44)heterodimer surface: A first principles study J Diffusion barriers Reconstruction Density functional calculations The adsorption and diffusion behavior functional theory (DFT) computations in the local density approxima- tion. Structural and bonding features

  9. I-V analysis of high-energy lithium-ion-irradiated Si and GaAs solar cells

    E-Print Network [OSTI]

    A. Meulenberg Jr; B. Jayashree; Ramani; M. C. Radhakrishna; A. K. Saif

    2007-09-07T23:59:59.000Z

    Space-grade Si and GaAs solar cells were irradiated with 15 and 40 MeV lithium ions. Dark-IV analysis (with and without illumination) reveals differences in the effects of such irradiation on the different cell types

  10. X-ray imaging and diffraction from surface phonons on GaAs W. Sauer,a)

    E-Print Network [OSTI]

    Ludwig-Maximilians-Universitt, Mnchen

    , the driver frequency of the synchrotron was multiplied 102 times by a phase-locked loop PLL , ampli- fied are excited on the GaAs 001 surface by using interdigital transducers, designed for frequencies of up to 900 to measured diffraction profiles at different excitation voltages, the SAW amplitudes were calculated

  11. Femtosecond-scale response of GaAs to ultrafast laser pulses Traian Dumitrica* and Roland E. Allen

    E-Print Network [OSTI]

    Allen, Roland E.

    Femtosecond-scale response of GaAs to ultrafast laser pulses Traian Dumitrica* and Roland E. Allen ordinary heating of the sample by phonon emission, there is convinc- ing evidence that ultrafast pulses of the initial stages of the interaction of a laser pulse with a semiconductor, which show that ultrafast disor

  12. Large-Signal HBT Model with Improved Collector Transit Time Formulation for GaAs and InP Technologies

    E-Print Network [OSTI]

    Asbeck, Peter M.

    mi': iaE Large-Signal HBT Model with Improved Collector Transit Time Formulation for GaAs and In large-signal HBT model which accurately accounts for the intricate hias dependence of collector delay collector delay function accounts for the variation of electron velocity with electric field

  13. Near-infrared sideband generation induced by intense far-infrared radiation in GaAs quantum wells

    E-Print Network [OSTI]

    Kono, Junichiro

    Near-infrared sideband generation induced by intense far-infrared radiation in GaAs quantum wells J illuminated with near-infrared NIR radiation at frequency nir and intense far-infrared FIR radiation from and quenching of photoluminescence PL .8,9 The nonlinear interaction of FIR and near-infrared NIR radiation

  14. High quality metamorphic graded buffers with lattice-constants intermediate to GaAs an InP for device applications

    E-Print Network [OSTI]

    Lee, Kenneth Eng Kian

    2009-01-01T23:59:59.000Z

    We have investigated the use of a continuous, linear grading scheme for compositionally-graded metamorphic InxGal-As buffers on GaAs, which can be used as virtual substrates for optical emitters operating at wavelengths > ...

  15. Energy distribution of nonequilibrium electrons and optical phonons in GaAs under band-to-band pumping by intense short pulses of light

    SciTech Connect (OSTI)

    Altybaev, G. S.; Kumekov, S. E., E-mail: skumekov@mail.ru; Mahmudov, A. A. [Satpaev Kazakh National Technical University (Kazakhstan)

    2009-03-15T23:59:59.000Z

    Deviation from the Fermi distribution of nonequilibrium electrons and distribution of 'hot' optical phonons in GaAs under band-to-band pumping by picosecond pulses of light are calculated.

  16. Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs

    SciTech Connect (OSTI)

    Hendra, P. I. B., E-mail: ib.hendra@gmail.com; Rahayu, F., E-mail: ib.hendra@gmail.com; Darma, Y., E-mail: ib.hendra@gmail.com [Physical Vapor Deposition Laboratory, Physics of Material Electronics Research, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

  17. Photoluminescence of GaAs films grown by vacuum chemical epitaxy

    SciTech Connect (OSTI)

    Bernussi, A.A.; Barreto, C.L.; Carvalho, M.M.G.; Motisuke, P.

    1988-08-01T23:59:59.000Z

    GaAs layers grown by vacuum chemical epitaxy (VCE) are investigated by low-temperature photoluminescence. A qualitative relation between the growth parameters and the shallow-impurity-incorporation mechanism is established. It was observed that the predominant shallow acceptor is carbon, and its incorporation during the growth process decreases with the As:Ga ratio, increases with growth temperature until 750 /sup 0/C, and then it diminishes. In this work we compare the characteristics observed in the VCE system with those in conventional molecular-beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD). Our results show that this system contains some advantages from both the MBE and MOCVD systems. The photoluminescence spectra also show that at low As:Ga ratios the generation of As vacancies or its complexes is strongly enhanced.

  18. Measurement of electron beam polarization from unstrained GaAs via two-photon photoemission

    SciTech Connect (OSTI)

    McCarter, James L. [Univ. of Virginia, Charlottesville, VA (United States); Afanasev, A. [George Washington Univ., Washingon, DC (United States); Gay, T. J. [Univ. of Nebraska, Lincoln, NE (United States); Hansknecht, John C. [JLAB, Newport News, VA (United States); Kechiantz, A. [George Washington Univ., Washingon, DC (United States); Poelker, B. Matthew [JLAB, Newport News, VA (United States)

    2014-02-01T23:59:59.000Z

    Two-photon absorption of 1560 nm light was used to generate polarized electron beams from unstrained GaAs photocathodes of varying thickness: 625 {mu}m, 0.32 {mu}m, and 0.18 {mu}m. For each photocathode, the degree of spin polarization of the photoemitted beam was less than 50%, contradicting earlier predictions based on simple quantum mechanical selection rules for spherically-symmetric systems but consistent with the more sophisticated model of Bhat et al. (Phys. Rev. B 71 (2005) 035209). Polarization via two-photon absorption was the highest from the thinnest photocathode sample and comparable to that obtained via one-photon absorption (using 778 nm light), with values 40.3 +- 1.0% and 42.6 +- 1.0%, respectively.

  19. Molecular-beam epitaxial growth of boron-doped GaAs films

    SciTech Connect (OSTI)

    Hoke, W.E.; Lemonias, P.J.; Weir, D.G. [Raytheon Research Division, Lexington, MA (United States)] [and others] [Raytheon Research Division, Lexington, MA (United States); and others

    1993-05-01T23:59:59.000Z

    GaAs films doped with boron in the 10{sup 20} cm{sup {minus}3} range were grown by solid source molecular-beam epitaxy. Lattice contractions were observed in x-ray double crystal spectra. Substitutional boron concentrations up to 1.7x10{sup 20} cm{sup {minus}3} were obtained with narrow x-ray linewidths and specular surface morphology. For a given boron flux, the substitutional concentration was dependent on growth temperature. P-type conductivity due to boron incorporation was measured in the films with hole concentration reaching 1x10{sup 19} cm{sup {minus}3}. The lattice contractions exhibited good thermal stability for rapid thermal anneals. 10 refs., 3 figs., 2 tabs.

  20. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    SciTech Connect (OSTI)

    Lastras-Martnez, A., E-mail: alm@cactus.iico.uaslp.mx, E-mail: alastras@gmail.com; Ortega-Gallegos, J.; Guevara-Macas, L. E.; Nuez-Olvera, O.; Balderas-Navarro, R. E.; Lastras-Martnez, L. F. [Instituto de Investigacin en Comunicacin Optica, Universidad Autnoma de San Luis Potos, Alvaro Obregn 64, San Luis Potos, SLP 78000 (Mexico); Lastras-Montao, L. A. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Lastras-Montao, M. A. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)

    2014-03-01T23:59:59.000Z

    We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500ms per spectrum within the 2.34.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

  1. Epitaxial lift-off of quantum dot enhanced GaAs single junction solar cells

    SciTech Connect (OSTI)

    Bennett, Mitchell F.; Bittner, Zachary S.; Forbes, David V.; Hubbard, Seth M., E-mail: smhsps@rit.edu [Rochester Institute of Technology, Rochester, New York 14623 (United States); Rao Tatavarti, Sudersena; Wibowo, Andree; Pan, Noren; Chern, Kevin [MicroLink Devices, Inc., Niles, Illinois 60714 (United States)] [MicroLink Devices, Inc., Niles, Illinois 60714 (United States); Phillip Ahrenkiel, S. [South Dakota School of Mines and Technology, Rapid City, South Dakota 57701 (United States)] [South Dakota School of Mines and Technology, Rapid City, South Dakota 57701 (United States)

    2013-11-18T23:59:59.000Z

    InAs/GaAs strain-balanced quantum dot (QD) n-i-p solar cells were fabricated by epitaxial lift-off (ELO), creating thin and flexible devices that exhibit an enhanced sub-GaAs bandgap current collection extending into the near infrared. Materials and optical analysis indicates that QD quality after ELO processing is preserved, which is supported by transmission electron microscopy images of the QD superlattice post-ELO. Spectral responsivity measurements depict a broadband resonant cavity enhancement past the GaAs bandedge, which is due to the thinning of the device. Integrated external quantum efficiency shows a QD contribution to the short circuit current density of 0.23?mA/cm{sup 2}.

  2. Fano Resonance in GaAs 2D Photonic Crystal Nanocavities

    SciTech Connect (OSTI)

    Valentim, P. T.; Guimaraes, P.S. S. [Departamento de Fisica, Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Instituto Nacional de Ciencia e Tecnologia de Nanodispositivos Semicondutores - INCT-DISSE (Brazil); Luxmoore, I. J.; Szymanski, D.; Whittaker, D. M.; Fox, A. M.; Skolnick, M. S. [Department of Physics and Astronomy, University of Sheffield, Sheffield (United Kingdom); Vasco, J. P. [Instituto de Fisica, Universidad de Antioquia, Medellin (Colombia); Vinck-Posada, H. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)

    2011-12-23T23:59:59.000Z

    We report the results of polarization resolved reflectivity experiments in GaAs air-bridge photonic crystals with L3 cavities. We show that the fundamental L3 cavity mode changes, in a controlled way, from a Lorentzian symmetrical lineshape to an asymmetrical form when the linear polarization of the incident light is rotated in the plane of the crystal. The different lineshapes are well fitted by the Fano asymmetric equation, implying that a Fano resonance is present in the reflectivity. We use the scattering matrix method to model the Fano interference between a localized discrete state (the cavity fundamental mode) and a background of continuum states (the light reflected from the crystal slab in the vicinity of the cavity) with very good agreement with the experimental data.

  3. Open-tube method for diffusion of zinc into GaAs

    SciTech Connect (OSTI)

    Field, R.J.; Ghandhi, S.K.

    1982-07-01T23:59:59.000Z

    Highly reproducible zinc diffusions from 0.03 to 1.5 /mu/m have been made into GaAs using a CVD zinc-doped silica source capped with phosphosilicate glass. This structure permitted the use of an open-tube, flowing inert gas diffusion system. Diffusions were made from 400/degree/ to 700/degree/C, with surface hole concentrations from 0.1 to 1.0*10/sup 20/ cm/sup -3/, and junction depths from 300A to 1.5 /mu/m. The diffusion coefficient and the hole concentration obtained by this technique are very close to those obtained by sealed ampul techniques using a Zn/sub 3/A/sub 2/ source. However, this open-tube system is more convenient to use, and gives highly reproducible results. 13 refs.

  4. Tailoring broadband light trapping of GaAs and Si substrates by self-organised nanopatterning

    SciTech Connect (OSTI)

    Martella, C.; Chiappe, D.; Mennucci, C.; Buatier de Mongeot, F. [Dipartimento di Fisica, Universit di Genova, via Dodecaneso 33, I-16146 Genova (Italy)

    2014-05-21T23:59:59.000Z

    We report on the formation of high aspect ratio anisotropic nanopatterns on crystalline GaAs (100) and Si (100) substrates exploiting defocused Ion Beam Sputtering assisted by a sacrificial self-organised Au stencil mask. The tailored optical properties of the substrates are characterised in terms of total reflectivity and haze by means of integrating sphere measurements as a function of the morphological modification at increasing ion fluence. Refractive index grading from sub-wavelength surface features induces polarisation dependent anti-reflection behaviour in the visible-near infrared (VIS-NIR) range, while light scattering at off-specular angles from larger structures leads to very high values of the haze functions in reflection. The results, obtained for an important class of technologically relevant materials, are appealing in view of photovoltaic and photonic applications aiming at photon harvesting in ultrathin crystalline solar cells.

  5. Intermediate-band material based on GaAs quantum rings for solar cells

    SciTech Connect (OSTI)

    Wu Jiang; Shao Dali [Department of Electrical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Li Zhenhua; Kunets, Vasyl P.; Wang Zhiming; Salamo, G. J. [Institute of Nanoscale Materials Science and Engineering, Fayetteville, Arkansas 72701 (United States); Manasreh, M. O. [Department of Electrical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Institute of Nanoscale Materials Science and Engineering, Fayetteville, Arkansas 72701 (United States)

    2009-08-17T23:59:59.000Z

    The intermediate-band concept is invoked to explain the photoresponse spectra obtained for unbiased devices fabricated from GaAs quantum rings grown by a droplet epitaxy technique on lattice-matched Al{sub 0.3}Ga{sub 0.7}As barriers. The photoresponse spectra where measured at room temperature in the visible-near-infrared spectral range. The presence of the intermediate band in the device active region is confirmed by measuring the mid-infrared photoresponse, which is attributed to the intersubband transitions in the conduction band. The photocurrent was measured at room temperature and found to be about four orders of magnitude larger than the dark current in the voltage range of {+-} 4.0 V.

  6. Charge tuning in [111] grown GaAs droplet quantum dots

    SciTech Connect (OSTI)

    Bouet, L.; Vidal, M.; Marie, X.; Amand, T.; Wang, G.; Urbaszek, B. [INSA-CNRS-UPS, LPCNO, Universit de Toulouse, 135 Ave. Rangueil, 31077 Toulouse (France); Mano, T.; Ha, N.; Kuroda, T.; Sakoda, K. [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Durnev, M. V.; Glazov, M. M.; Ivchenko, E. L. [Ioffe Physical-Technical Institute RAS, 194021 St.-Petersburg (Russian Federation)

    2014-08-25T23:59:59.000Z

    We demonstrate charge tuning in strain free GaAs/AlGaAs quantum dots (QDs) grown by droplet epitaxy on a GaAs(111)A substrate. Application of a bias voltage allows the controlled charging of the QDs from ?3|e| to +2|e|. The resulting changes in QD emission energy and exciton fine-structure are recorded in micro-photoluminescence experiments at T?=?4?K. We uncover the existence of excited valence and conduction states, in addition to the s-shell-like ground state. We record a second series of emission lines about 25?meV above the charged exciton emission coming from excited charged excitons. For these excited interband transitions, a negative diamagnetic shift of large amplitude is uncovered in longitudinal magnetic fields.

  7. Piezoelectric surface acoustical phonon amplification in graphene on a GaAs substrate

    SciTech Connect (OSTI)

    Nunes, O. A. C., E-mail: oacn@unb.br [Institute of Physics, University of Brasilia, Brasilia, 70910-900 DF (Brazil)

    2014-06-21T23:59:59.000Z

    We study the interaction of Dirac Fermions in monolayer graphene on a GaAs substrate in an applied electric field by the combined action of the extrinsic potential of piezoelectric surface acoustical phonons of GaAs (piezoelectric acoustical (PA)) and of the intrinsic deformation potential of acoustical phonons in graphene (deformation acoustical (DA)). We find that provided the dc field exceeds a threshold value, emission of piezoelectric (PA) and deformation (DA) acoustical phonons can be obtained in a wide frequency range up to terahertz at low and high temperatures. We found that the phonon amplification rate R{sup PA,DA} scales with T{sub BG}{sup S?1} (S=PA,DA), T{sub BG}{sup S} being the Block?Gru{sup }neisen temperature. In the high-T Block?Gru{sup }neisen regime, extrinsic PA phonon scattering is suppressed by intrinsic DA phonon scattering, where the ratio R{sup PA}/R{sup DA} scales with ?1/?(n), n being the carrier concentration. We found that only for carrier concentration n?10{sup 10}cm{sup ?2}, R{sup PA}/R{sup DA}>1. In the low-T Block?Gru{sup }neisen regime, and for n=10{sup 10}cm{sup ?2}, the ratio R{sup PA}/R{sup DA} scales with T{sub BG}{sup DA}/T{sub BG}{sup PA}?7.5 and R{sup PA}/R{sup DA}>1. In this regime, PA phonon dominates the electron scattering and R{sup PA}/R{sup DA}<1 otherwise. This study is relevant to the exploration of the acoustic properties of graphene and to the application of graphene as an acoustical phonon amplifier and a frequency-tunable acoustical phonon device.

  8. EL2-related studies in irradiated and implanted GaAs Laboratoire de Physique de la Matire (associ au CNRS), Institut National des Sciences Appliques de Lyon,

    E-Print Network [OSTI]

    Boyer, Edmond

    donneur profond EL2 est un défaut très important par le rôle qu'il joue dans la compensation du matériau in the compensation of undoped semi-insulating GaAs. The knowledge of the exact EL2 structure becomes of even greater semi-insulating (SI) GaAs uses the liquid- encapsulated Czochralski process with the As vapor pressure

  9. Microstructure characterization of Cu,Ge/n-type GaAs ohmic contacts M. 0. Aboelfotoh, S. Oktyabrsky, and J. Narayan

    E-Print Network [OSTI]

    Woodall, Jerry M.

    contacts of Ge/Pd/n-type GaAs have been proposed.4 This contact scheme involves the deposition of a metal at 325 "C for 30 min, the entire layer of Pd is consumed in the formation of a palladium germanide layer to the Ge/Pd contacts,' and that n-channel GaAs metal- semiconductor field-effect transistors using the q

  10. Highly uniform, multi-stacked InGaAs/GaAs quantum dots embedded in a GaAs nanowire

    SciTech Connect (OSTI)

    Tatebayashi, J., E-mail: tatebaya@iis.u-tokyo.ac.jp; Ota, Y. [NanoQUINE, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Ishida, S.; Nishioka, M.; Iwamoto, S.; Arakawa, Y. [NanoQUINE, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Institute of Industrial Science, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

    2014-09-08T23:59:59.000Z

    We demonstrate a highly uniform, dense stack of In{sub 0.22}Ga{sub 0.78}As/GaAs quantum dot (QD) structures in a single GaAs nanowire (NW). The size (and hence emission energy) of individual QD is tuned by careful control of the growth conditions based on a diffusion model of morphological evolution of NWs and optical characterization. By carefully tailoring the emission energies of individual QD, dot-to-dot inhomogeneous broadening of QD stacks in a single NW can be as narrow as 9.3?meV. This method provides huge advantages over traditional QD stack using a strain-induced Stranski-Krastanow growth scheme. We show that it is possible to fabricate up to 200 uniform QDs in single GaAs NWs using this growth technique without degradation of the photoluminescence intensity.

  11. Influence of uniaxial pressure on the critical temperature for long delays in GaAs junction lasers

    SciTech Connect (OSTI)

    Morosini, M.B.Z.; Patel, N.B.; Nunes, F.D.

    1980-09-01T23:59:59.000Z

    In this work we report on the influence of uniaxial pressure applied perpendicularly to junction laser on the behavior of the critical temperature for the onset of long delays in GaAs junction lasers. Experimental data showing this influence for lasers operating in a TE or TM polarization are presented and explained on the basis of a thermal theory of long delays and related phenomena.

  12. COMPARATIVE STUDY OF CdTe AND GaAs PHOTOREFRACTIVE PERFORMANCES FROM 1m TO 1.55m

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 COMPARATIVE STUDY OF CdTe AND GaAs PHOTOREFRACTIVE PERFORMANCES FROM 1µm TO 1.55µm L.A. de CdTe at different wavelengths from 1.06µm to 1.55µm. The sensitivity and performances of different for the extension of the photorefractive effect towards the wavelength region of 1.3-1.5µm. CdTe appears

  13. Atomic-scale observation of parallel development of super elasticity and reversible plasticity in GaAs nanowires

    SciTech Connect (OSTI)

    Bao, Peite; Du, Sichao; Zheng, Rongkun, E-mail: rongkun.zheng@sydney.edu.au [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia); Wang, Yanbo; Liao, Xiaozhou, E-mail: xiaozhou.liao@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Cui, Xiangyuan; Yen, Hung-Wei; Kong Yeoh, Wai; Ringer, Simon P. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Gao, Qiang; Hoe Tan, H.; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Liu, Hongwei [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Zou, Jin [Materials Engineering and Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD 4072 (Australia)

    2014-01-13T23:59:59.000Z

    We report the atomic-scale observation of parallel development of super elasticity and reversible dislocation-based plasticity from an early stage of bending deformation until fracture in GaAs nanowires. While this phenomenon is in sharp contrast to the textbook knowledge, it is expected to occur widely in nanostructures. This work indicates that the super recoverable deformation in nanomaterials is not simple elastic or reversible plastic deformation in nature, but the coupling of both.

  14. dc field-emission analysis of GaAs and plasma-source ion-implanted stainless steel

    SciTech Connect (OSTI)

    C. Hernandez; T. Wang; T. Siggins; D. Bullard; H. F. Dylla; C. Reece; N. D. Theodore; D. M. Manos

    2003-06-01T23:59:59.000Z

    Field-emission studies have been performed on a GaAs wafer and a sample of its stainless-steel (SS) support electrode that are part of a photocathode gun for the 10 kW Upgrade infrared free electron laser at Jefferson Lab. The objective of the studies presented here is to characterize the effect of both the cleanliness of the wafer and the plasma-source ion-implanted layer on the electrode to suppress field emission. Field emission is the limiting factor to achieve the required 6 MV/m at the surface of the wafer. Potential field emitters are first located on the surface of 1 in. diameter samples with a dc scanning field-emission microscope at 60 MV/m, then each emitter is characterized in a scanning electron microscope equipped with an energy dispersive spectrometer. The GaAs wafer was hydrogen cleaned before the study. The results show three emitters caused by indium contamination during wafer handling. The GaAs wafer thus shows good high-voltage characteristics and the need to maintain cleanliness during handling. The SS sample is hand polished with diamond paste to a 1-m surface finish, then implanted with N2/SiO2 in a plasma-source ion-implantation chamber in preparation for the field-emission studies.

  15. Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

    SciTech Connect (OSTI)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2010-05-23T23:59:59.000Z

    RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is expected to improve further. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper.

  16. X-ray pump optical probe cross-correlation study of GaAs

    SciTech Connect (OSTI)

    Durbin, S.M.; Clevenger, T.; Graber, T.; Henning, R. (Purdue); (UC)

    2012-09-10T23:59:59.000Z

    Ultrafast dynamics in atomic, molecular and condensed-matter systems are increasingly being studied using optical-pump, X-ray probe techniques where subpicosecond laser pulses excite the system and X-rays detect changes in absorption spectra and local atomic structure. New opportunities are appearing as a result of improved synchrotron capabilities and the advent of X-ray free-electron lasers. These source improvements also allow for the reverse measurement: X-ray pump followed by optical probe. We describe here how an X-ray pump beam transforms a thin GaAs specimen from a strong absorber into a nearly transparent window in less than 100 ps, for laser photon energies just above the bandgap. We find the opposite effect - X-ray induced optical opacity - for photon energies just below the bandgap. This raises interesting questions about the ultrafast many-body response of semiconductors to X-ray absorption, and provides a new approach for an X-ray/optical cross-correlator for synchrotron and X-ray free-electron laser applications.

  17. Heat load of a P-doped GaAs photocathode in SRF electron gun

    SciTech Connect (OSTI)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Jain, A.; Gupta, R.; Holmes, D.

    2010-05-23T23:59:59.000Z

    Many efforts were made over the last decades to develop a better polarized electron source for the high energy physics. Several laboratories operate DC guns with the Gallium-Arsenide photo-cathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved using a Superconducting RF electron gun, which delivers beams of higher brightness than DC guns does, because the field gradient at the cathode is higher. SRF guns with metal cathodes and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since the cathode will be normal conducting, the problem about the heat load stemming from the cathode arises. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and the verification by measuring the quality factor of the gun with and without cathode.

  18. Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System

    SciTech Connect (OSTI)

    M.L. Stutzman; P. Adderley; J. Brittian; J. Clark; J. Grames; J. Hansknecht; G.R. Myneni; M. Poelker

    2007-05-01T23:59:59.000Z

    A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower part of the UHV range. Measured NEG pump speed is high at pressures above 510^?11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.

  19. Thermal influence on charge carrier transport in solar cells based on GaAs PN junctions

    SciTech Connect (OSTI)

    Osses-Mrquez, Juan; Caldern-Muoz, Williams R., E-mail: wicalder@ing.uchile.cl [Department of Mechanical Engineering, University of Chile, Beauchef 850, Santiago (Chile)

    2014-10-21T23:59:59.000Z

    The electron and hole one-dimensional transport in a solar cell based on a Gallium Arsenide (GaAs) PN junction and its dependency with electron and lattice temperatures are studied here. Electrons and heat transport are treated on an equal footing, and a cell operating at high temperatures using concentrators is considered. The equations of a two-temperature hydrodynamic model are written in terms of asymptotic expansions for the dependent variables with the electron Reynolds number as a perturbation parameter. The dependency of the electron and hole densities through the junction with the temperature is analyzed solving the steady-state model at low Reynolds numbers. Lattice temperature distribution throughout the device is obtained considering the change of kinetic energy of electrons due to interactions with the lattice and heat absorbed from sunlight. In terms of performance, higher values of power output are obtained with low lattice temperature and hot energy carriers. This modeling contributes to improve the design of heat exchange devices and thermal management strategies in photovoltaic technologies.

  20. Multi-junction, monolithic solar cell using low-band-gap materials lattice matched to GaAs or Ge

    DOE Patents [OSTI]

    Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO); Friedman, Daniel J. (Lakewood, CO)

    2001-01-01T23:59:59.000Z

    A multi-junction, monolithic, photovoltaic solar cell device is provided for converting solar radiation to photocurrent and photovoltage with improved efficiency. The solar cell device comprises a plurality of semiconductor cells, i.e., active p/n junctions, connected in tandem and deposited on a substrate fabricated from GaAs or Ge. To increase efficiency, each semiconductor cell is fabricated from a crystalline material with a lattice constant substantially equivalent to the lattice constant of the substrate material. Additionally, the semiconductor cells are selected with appropriate band gaps to efficiently create photovoltage from a larger portion of the solar spectrum. In this regard, one semiconductor cell in each embodiment of the solar cell device has a band gap between that of Ge and GaAs. To achieve desired band gaps and lattice constants, the semiconductor cells may be fabricated from a number of materials including Ge, GaInP, GaAs, GaInAsP, GaInAsN, GaAsGe, BGaInAs, (GaAs)Ge, CuInSSe, CuAsSSe, and GaInAsNP. To further increase efficiency, the thickness of each semiconductor cell is controlled to match the photocurrent generated in each cell. To facilitate photocurrent flow, a plurality of tunnel junctions of low-resistivity material are included between each adjacent semiconductor cell. The conductivity or direction of photocurrent in the solar cell device may be selected by controlling the specific p-type or n-type characteristics for each active junction.

  1. Chirped-pulse manipulated carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs

    SciTech Connect (OSTI)

    Lee, Chao-Kuei, E-mail: chuckcklee@yahoo.com [Department of Photonics, National Sun-Yat-Sen University, Kaohsiung 80400, Taiwan (China); Lin, Yuan-Yao [Department of Electrical Engineering, Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30010, Taiwan (China); Lin, Sung-Hui [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Lin, Gong-Ru [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan (China); Pan, Ci-Ling [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Physics, National Tsing Hwa University, Hsinchu 30010, Taiwan (China)

    2014-04-28T23:59:59.000Z

    Chirped pulse controlled carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs are investigated by degenerate pump-probe technique. Varying the chirped condition of excited pulse from negative to positive increases the carrier relaxation time so as to modify the dispersion and reshape current pulse in time domain. The spectral dependence of carrier dynamics is analytically derived and explained by Shockley-Read Hall model. This observation enables the new feasibility of controlling carrier dynamics in ultrafast optical devices via the chirped pulse excitations.

  2. Influence of GaAs surface termination on GaSb/GaAs quantum dot structure and band offsets

    SciTech Connect (OSTI)

    Zech, E. S.; Chang, A. S.; Martin, A. J.; Canniff, J. C.; Millunchick, J. M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Lin, Y. H. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)

    2013-08-19T23:59:59.000Z

    We have investigated the influence of GaAs surface termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of surface termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.

  3. The Influence of High-Energy Lithium Ion Irradiation on Electrical Characteristics of Silicon and GaAs Solar Cells

    E-Print Network [OSTI]

    B. Jayashree; Ramani; M. C. Radhakrishna; Anil Agrawal; Saif Ahmad Khan; A. Meulenberg

    2006-10-22T23:59:59.000Z

    Space-grade Si and GaAs solar cells were irradiated with 15 & 40 MeV Li ions. Illuminated (AM0 condition) and unilluminated I-V curves reveal that the effect of high-energy Li ion irradiation has produced similar effects to that of proton irradiation. However, an additional, and different, defect mechanism is suggested to dominate in the heavier-ion results. Comparison is made with proton-irradiated solar-cell work and with non-ionizing energy-loss (NIEL) radiation-damage models.

  4. Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots

    SciTech Connect (OSTI)

    Belhadj, T.; Amand, T.; Kunz, S.; Marie, X.; Urbaszek, B. [INSA-CNRS-UPS, LPCNO, Universite de Toulouse, 135 Av. Rangueil, 31077 Toulouse (France); Kunold, A. [INSA-CNRS-UPS, LPCNO, Universite de Toulouse, 135 Av. Rangueil, 31077 Toulouse (France); Departamento de Ciencias Basicas, UAM-A, Col. Reynosa Tamaulipas, 02200 Mexico D.F. (Mexico); Simon, C.-M. [INSA-CNRS-UPS, LPCNO, Universite de Toulouse, 135 Av. Rangueil, 31077 Toulouse (France); CNRS-UPS, LCAR, IRSAMC, Universite de Toulouse, 31062 Toulouse (France); Kuroda, T.; Abbarchi, M.; Mano, T.; Sakoda, K. [National Institute for Material Science, Namiki 1-1, Tsukuba 305-0044 (Japan)

    2010-08-02T23:59:59.000Z

    We report strong heavy hole-light hole mixing in GaAs quantum dots grown by droplet epitaxy. Using the neutral and charged exciton emission as a monitor we observe the direct consequence of quantum dot symmetry reduction in this strain free system. By fitting the polar diagram of the emission with simple analytical expressions obtained from k{center_dot}p theory we are able to extract the mixing that arises from the heavy-light hole coupling due to the geometrical asymmetry of the quantum dot.

  5. Highly polarized emission in spin resolved photoelectron spectroscopy of alpha-Fe(001)/GaAs(001)

    SciTech Connect (OSTI)

    Tobin, James; Yu, Sung Woo; Morton, Simon; Waddill, George; Thompson, Jamie; Neal, James; Spangenberg, Matthais; Shen, T.H.

    2009-05-19T23:59:59.000Z

    Highly spin-polarized sources of electrons, Integrated into device design, remain of great interest to the spintronic and magneto-electronic device community Here, the growth of Fe upon GaAs(001) has been studied with photoelectron spectroscopy (PES), including Spin Resolved PES. Despite evidence of atomic level disorder such as intermixing, an over-layer with the spectroscopic signature of alpha-Fe(001), with a bcc real space ordering, Is obtained The results will be discussed in light of the possibility of using such films as a spin-polarized source in device applications.

  6. General engineering specifications for 6000 tpd SRC-I Demonstration Plant

    SciTech Connect (OSTI)

    Not Available

    1981-11-01T23:59:59.000Z

    This volume contains specifications for architectural features of buildings for the SRC-1 Demonstration Plant: skylights, ventilators, sealants, doors, mirrors, furring and lathing, gypsum plaster, lightweight plaster, wallboard, ceramic tile, acoustic ceiling systems, resilient flooring, carpeting, brick flooring, architectural painting, vinyl wall covering, chalkboards, tackboards, toilets, access flooring, lockers, partitions, washroom accessories, unit kitchens, dock levels, seals, shelters, custom casework, auditorium seats, drapery tacks, prefabricated buildings, stairs, elevators, shelves, etc. (LTN).

  7. High-field electroluminescence in semiconductor tunnel junctions with a Mn-doped GaAs layer

    SciTech Connect (OSTI)

    Hai, Pham Nam [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-0033 (Japan); Yatsui, Takashi; Ohtsu, Motoichi; Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nanophotonics Research Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2014-09-21T23:59:59.000Z

    We investigated high-field electroluminescence (EL) in semiconductor tunnel junctions with a Mn-doped GaAs layer (here, referred to as GaAs:Mn). Besides the band-gap emission of GaAs, the EL spectra show visible light emissions with two peaks at 1.94?eV and 2.19?eV, which are caused by d-d transitions of the Mn atoms excited by hot electrons. The threshold voltages for band-gap and visible light EL in the tunnel junctions with a GaAs:Mn electrode are 1.3?V higher than those of GaAs:Mn excited by hot holes in reserve biased p{sup +}-n junctions, which is consistent with the hot carrier transport in the band profiles of these structures. Our EL results at room temperature show that the electron temperature in GaAs:Mn can be as high as ?700?K for a low input electrical power density of 0.4?W/cm{sup 2}, while the lattice temperature of the GaAs:Mn layer can be kept at 340?K.

  8. ELSEWER Journal of Magnetism and Magnetic Materials 169 (1997) 261-270 Superparamagnetic behavior of Fe,GaAs precipitates in GaAs

    E-Print Network [OSTI]

    Woodall, Jerry M.

    ELSEWER Journal of Magnetism and Magnetic Materials 169 (1997) 261-270 Superparamagnetic behavior; revised 6 December 1996 Abstract We present magnetization measurements on Fe3GaAs clusters distributed-dependent magnetization well above the blocking temperature indicate a particle size distribution in agreement

  9. Ab initio cluster calculations of hydrogenated GaAs,,001... surfaces Chemical Engineering Department, University of California, Los Angeles, California 90095-1592

    E-Print Network [OSTI]

    Li, Lian

    Ab initio cluster calculations of hydrogenated GaAs,,001... surfaces Q. Fu Chemical Engineering Engineering Department, University of California, Los Angeles, California 90095-1592 Received 11 November 1999 Hydrogen adsorption on the 2 4 and 4 2 reconstructions of gallium arsenide 001 has been studied by internal

  10. Self-cleaning and surface recovery with arsine pretreatment in ex situ atomic-layer-deposition of Al2O3 on GaAs

    E-Print Network [OSTI]

    /Thomas Swan close-coupled showerhead cold-wall MOCVD system. The buffer epilayers of GaAs were grown on 2 in for these interfaces. In addition, when designing an in situ MOCVD process, the typical TMA/H2O is incompatible

  11. Metal-insulator-semiconductor structure on low-temperature grown GaAs M. Young, W. Li, and T. P. Ma

    E-Print Network [OSTI]

    Woodall, Jerry M.

    Metal-insulator-semiconductor structure on low-temperature grown GaAs A. Chen,a M. Young, W. Li Received 28 July 2006; accepted 30 October 2006; published online 7 December 2006 The metal-insulator dielectrics and metal-insulator-semiconductor MIS structures; for ex- ample, in situ deposited Ga2O3 Gd2O3

  12. Control of the dephasing process due to many-body interactions among excitons by using non-Markovian effect in GaAs single quantum well

    SciTech Connect (OSTI)

    Ogawa, Y.; Minami, F. [Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan)

    2013-12-04T23:59:59.000Z

    We show the coherent control of dephasing process of exciton polarization due to heavy hole-heavy hole and heavy hole-light hole scatterings in a GaAs single quantum well. The memory time of the exction scattering is estimated as 0.47 ps.

  13. Vacancy migration, adatom motion, a.nd atomic bistability on the GaAs(110) surface studied by scanning tunneling microscopy

    E-Print Network [OSTI]

    Vacancy migration, adatom motion, a.nd atomic bistability on the GaAs(110) surface studied temperature are reported. The slow dynamic behavior of vacancies and As adatoms can be resolved within a time scale of about one minute, The vacancies and As adatoms are observed to move preferably along the [110

  14. Molecular Beam Epitaxial Growth of Bi2Te3 and Sb2Te3 Topological Insulators on GaAs (111) Substrates: A Potential Route to Fabricate Topological Insulator p-n Junction

    E-Print Network [OSTI]

    Zhaoquan Zeng; Timothy A. Morgan; Dongsheng Fan; Chen Li; Yusuke Hirono; Xian Hu; Yanfei Zhao; Joon Sue Lee; Zhiming M. Wang; Jian Wang; Shuiqing Yu; Michael E. Hawkridge; Mourad Benamara; Gregory J. Salamo

    2013-03-11T23:59:59.000Z

    High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111) substrate is better than a vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3 topological insulator films can be directly grown on a GaAs (111) substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.

  15. Kinetics of band bending and electron affinity at GaAs(001) surface with nonequilibrium cesium overlayers

    SciTech Connect (OSTI)

    Zhuravlev, A. G.; Savchenko, M. L.; Paulish, A. G.; Alperovich, V. L. [Rzhanov Institute of Semiconductor Physics, Lavrentieva, 13, 630090 Novosibirsk, Russia and Novosibirsk State University, Pirogova, 2, 630090 Novosibirsk (Russian Federation); Scheibler, H. E.; Jaroshevich, A. S. [Rzhanov Institute of Semiconductor Physics, Lavrentieva, 13, 630090 Novosibirsk (Russian Federation)

    2013-12-04T23:59:59.000Z

    The dosage dependences of surface band bending and effective electron affinity under cesium deposition on the Ga-rich GaAs(001) surface, along with the relaxation of these electronic properties after switching off the Cs source are experimentally studied by means of modified photoreflectance spectroscopy and photoemission quantum yield spectroscopy. At small Cs coverages, below half of a monolayer, additional features in the dosage dependence and subsequent downward relaxation of the photoemission current are determined by the variations of band bending. At coverages above half of a monolayer the upward relaxation of the photocurrent is caused supposedly by the decrease of the electron affinity due to restructuring in the nonequilibrium cesium overlayer.

  16. Strong enhancement of terahertz emission from GaAs in InAs/GaAs quantum dot structures

    SciTech Connect (OSTI)

    Estacio, Elmer; Pham, Minh Hong; Takatori, Satoru; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Sarukura, Nobuhiko [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Somintac, Armando; Defensor, Michael; Awitan, Fritz Christian B.; Jaculbia, Rafael B.; Salvador, Arnel [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Garcia, Alipio [Department of Physical Sciences, University of the Philippines, Baguio City 2600 (Philippines)

    2009-06-08T23:59:59.000Z

    We report on the intense terahertz emission from InAs/GaAs quantum dot (QD) structures grown by molecular beam epitaxy. Results reveal that the QD sample emission was as high as 70% of that of a p-type InAs wafer, the most intense semiconductor emitter to date. Excitation wavelength studies showed that the emission was due to absorption in strained undoped GaAs, and corresponds to a two order-of-magnitude enhancement. Moreover, it was found that multilayer QDs emit more strongly compared with a single layer QD sample. At present, we ascribe the intense radiation to huge strain fields at the InAs/GaAs interface.

  17. Perpendicular-to-Parallel Spin Reorientation in a Mn-Doped GaAs Quantum Canting or Phase Separation

    SciTech Connect (OSTI)

    Fishman, Randy Scott [ORNL; Reboredo, Fernando A [ORNL; Brandt, Alex B [ORNL; Moreno, Juana [University of North Dakota, Grand Forks

    2007-01-01T23:59:59.000Z

    It is well known that the magnetic anisotropy in a compressively-strained Mn-doped GaAs film changes from perpendicular to parallel with increasing hole concentration p. We study this reorientation transition at T = 0 for a quantum well with Mn impurities confined to the z = 0 plane. With increasing p, the angle 0 that minimizes the energy E increases continuously from 0 (perpendicular anisotropy) to /2 (parallel anisotropy) within some range of p. The shape of Emin(p) suggests that the quantum well becomes phase separated with regions containing low hole concentrations and perpendicular moments interspersed with other regions containing high hole concentrations and parallel moments. However, consideration of the Coulomb energy costs associated with phase separation suggests that the true magnetic state in the transition region is canted with 0 < < /2.

  18. Calculations of bound and resonant electronic states for the GaAs (111) (2x2) reconstructed surface

    E-Print Network [OSTI]

    Blount, Samuel Stephen

    2012-06-07T23:59:59.000Z

    the degree ol' MASTER OF SCIEVCE December 19ftg Major Subject: Phys)cs CALCULATIONS OF BOUND AiND RESONAiNT ELECTRONIC STATES FOR THE GaAs [111) (2x2) RECONSTRUCTED SURFACE A Thesis by SAMUEL STEPHEiN BLOUNT Approved as to style and content by...), ? 3eV. & E & 2eV 8] (0. 2859, 0. 2268), ? 13eV. & E & ? 8eV. . 82 (0. 2859, 0. 2268). ? 8el'. & E & ? 3eV. . . 83 (0. 2859, 0. 2268), ? 3eV. & E & 2eV. 84 (0. 3569, 0, 2268), ? 13eV ( E & ? 8eV. . 76 (0. 3569, 0. 2268), ? 8eV. & E & ? 3eV. . . 77...

  19. Carrier-induced change in refractive index of InP, GaAs, and InGaAsP

    SciTech Connect (OSTI)

    Bennett, B.R. (Dept. of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA (US)); Soref, R.A. (Solid State Sciences Directorate, Rome Air Development Center, Hanscom Air Force Base, Bedford, MA (US)); Del Alamo, J.A. (Dept. of Electrical Engineering and Computer Science, Massachussets Institute of Technology, Cambridge, MA (US))

    1990-01-01T23:59:59.000Z

    The authors have theoretically estimated the change in refractive index {Delta}{ital n} produced by injection of free carriers in InP, GaAs, and InGaAsP. Bandfilling (Burstein-Moss effect), band-gap shrinkage, and free-carrier absorption (plasma effect) were included. Carrier concentrations of 10{sup 16}/cm{sup 3} to 10{sup 19}/cm{sup 3} and photon energies of 0.8 to 2.0 eV were considered. Predictions of {Delta}{ital n} are in reasonably good agreement with the limited experimental data available. Refractive index changes as large as 10{sup {minus} 2} are predicted for carrier concentrations of 10{sup 18}/cm{sup 3}, suggesting that low-loss optical phase modulators and switches using carrier injection are feasible in these materials.

  20. Electron Transport Behavior on Gate Length Scaling in Sub-50 nm GaAs Metal Semiconductor Field Effect Transistors

    SciTech Connect (OSTI)

    Han, Jaeheon [Department of Electronic Engineering, Kangnam University, 111 Gugal-dong, Giheung-gu, Yongin-city, Gyeonggi-do, Korea 446-702 (Korea, Republic of)

    2011-12-23T23:59:59.000Z

    Short channel GaAs Metal Semiconductor Field Effect Transistors (MESFETs) have been fabricated with gate length to 20 nm, in order to examine the characteristics of sub-50 nm MESFET scaling. Here the rise in the measured transconductance is mainly attributed to electron velocity overshoot. For gate lengths below 40 nm, however, the transconductance drops suddenly. The behavior of velocity overshoot and its degradation is investigated and simulated by using a transport model based on the retarded Langevin equation (RLE). This indicates the existence of a minimum acceleration length needed for the carriers to reach the overshoot velocity. The argument shows that the source resistance must be included as an internal element, or appropriate boundary condition, of relative importance in any model where the gate length is comparable to the inelastic mean free path of the carriers.

  1. Magnetic anisotropies in epitaxial Fe{sub 3}O{sub 4}/GaAs(100) patterned structures

    SciTech Connect (OSTI)

    Zhang, W., E-mail: xiaotur@gmail.com; Zhang, D.; Yuan, S. J.; Huang, Z. C.; Zhai, Y. [Department of Physics, Southeast University, Nanjing 211189 (China); Wong, P. K. J. [NanoElectronics Group, MESA Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede (Netherlands); Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 (Singapore); Wu, J. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Xu, Y. B. [Spintronics and Nanodevice Laboratory, Department of Electronics, University of York, York, YO10 5DD (United Kingdom)

    2014-10-15T23:59:59.000Z

    Previous studies on epitaxial Fe{sub 3}O{sub 4} rings in the context of spin-transfer torque effect have revealed complicated and undesirable domain structures, attributed to the intrinsic fourfold magnetocrystalline anisotropy in the ferrite. In this Letter, we report a viable solution to this problem, utilizing a 6-nm-thick epitaxial Fe{sub 3}O{sub 4} thin film on GaAs(100), where the fourfold magnetocrystalline anisotropy is negligible. We demonstrate that in the Fe{sub 3}O{sub 4} planar wires patterned from our thin film, such a unique magnetic anisotropy system has been preserved, and relatively simple magnetic domain configurations compared to those previous reports can be obtained.

  2. Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

    SciTech Connect (OSTI)

    Dinetta, L.C.; Hannon, M.H.

    1995-10-01T23:59:59.000Z

    Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products.

  3. Investigation of ultrafast photothermal surface expansion and diffusivity in GaAs via laser-induced dynamic gratings

    SciTech Connect (OSTI)

    Pennington, D.M.

    1992-04-01T23:59:59.000Z

    This thesis details the first direct ultrafast measurements of the dynamic thermal expansion of a surface and the temperature dependent surface thermal diffusivity using a two-color reflection transient grating technique. Studies were performed on p-type, n-type, and undoped GaAs(100) samples over a wide range of temperatures. By utilizing a 90 fs ultraviolet probe with visible excitation beams, the effects of interband saturation and carrier dynamics become negligible; thus lattice expansion due to heating and subsequent contraction caused by cooling provided the dominant influence on the probe. At room temperature a rise due to thermal expansion was observed, corresponding to a maximum net displacement of {approximately} 1 {Angstrom} at 32 ps. The diffracted signal was composed of two components, thermal expansion of the surface and heat flow away from the surface, thus allowing a determination of the rate of expansion as well as the surface thermal diffusivity, D{sub S}. By varying the fringe spacing of the grating, this technique has the potential to separate the signal contributions to the expansion of the lattice in the perpendicular and parallel directions. In the data presented here a large fringe spacing was used, thus the dominant contribution to the rising edge of the signal was expansion perpendicular to the surface. Comparison of he results with a straightforward thermal model yields good agreement over a range of temperatures (20--300{degrees}K). Values for D{sub S} in GaAs were measured and found to be in reasonable agreement with bulk values above 50{degrees}K. Below 50{degrees}K, D{sub S} were determined to be up to an order of magnitude slower than the bulk diffusivity due to increased phonon boundary scattering. The applicability and advantages of the TG technique for studying photothermal and photoacoustic phenomena are discussed.

  4. Impact of artificial lateral quantum confinement on exciton-spin relaxation in a two-dimensional GaAs electronic system

    SciTech Connect (OSTI)

    Kiba, Takayuki, E-mail: tkiba@ist.hokudai.ac.jp; Murayama, Akihiro [Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo (Japan); CREST Japan Science and Technology Agency, 5 Sanbancho, Chiyoda-ku, Tokyo (Japan); Tanaka, Toru [Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo (Japan); Tamura, Yosuke [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); Higo, Akio [WPI-AIMR, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); Thomas, Cedric [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); CREST Japan Science and Technology Agency, 5 Sanbancho, Chiyoda-ku, Tokyo (Japan); Samukawa, Seiji [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); WPI-AIMR, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); CREST Japan Science and Technology Agency, 5 Sanbancho, Chiyoda-ku, Tokyo (Japan)

    2014-10-15T23:59:59.000Z

    We demonstrate the effect of artificial lateral quantum confinement on exciton-spin relaxation in a GaAs electronic system. GaAs nanodisks (NDs) were fabricated from a quantum well (QW) by top-down nanotechnology using neutral-beam etching aided by protein-engineered bio-nano-templates. The exciton-spin relaxation time was 1.4 ns due to ND formation, significantly extended compared to 0.44 ns for the original QW, which is attributed to weakening of the hole-state mixing in addition to freezing of the carrier momentum. The temperature dependence of the spin-relaxation time depends on the ND thickness, reflecting the degree of quantum confinement.

  5. A 77 GHz Transceiver for Automotive Radar System Using a120nm In AlAs/In GaAs Metamorphic HEMTs

    E-Print Network [OSTI]

    Kwon, Youngwoo

    A 77 GHz Transceiver for Automotive Radar System Using a120nm 0.4 0.35 In AlAs/In GaAs Metamorphic-mail:ykwon@snu.ac.kr) Abstract -- In this work, we demonstrate a compact 77GHz single-chip transceiver for an automotive radar at the transmitter and a 5dB conversion gain at the receiver. Index Terms -- Automotive radar, 77GHz, MHEMT, MMIC

  6. Discrimination between energy transfer and back transfer processes for GaAs host and Er luminescent dopants using electric response analysis

    SciTech Connect (OSTI)

    Ishii, Masashi, E-mail: ISHII.Masashi@nims.go.jp [National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan); Koizumi, Atsushi; Fujiwara, Yasufumi [Division of Materials and Manufacturing Science, Graduate School of Engineering Osaka University, Suita, Osaka 565-0871 (Japan); Takeda, Yoshikazu [Nagoya Industrial Science Research Institute, Nagoya, Aichi 464-0819 (Japan)

    2014-04-07T23:59:59.000Z

    The energy transfer and back transfer processes of GaAs co-doped with Er and O (GaAs:Er,O) were experimentally distinguished by using a frequency response analysis of the AC photocurrent. The results were achieved by using the difference in the frequency dispersion between (1) the dispersion of the energy transfer, which is triggered by the trapping of free charges in the GaAs host and is represented with the Debye relaxation response and (2) the dispersion of the energy back transfer, which is induced by non-radiative transition of 4f bound electrons in the Er dopants and is described with a Lorentzian. The Debye relaxation response found in GaAs:Er,O provided a charge trapping time that was dependent on temperature, which was well correlated with the thermal quenching property of intense intra-4f-shell luminescence. The spectral shape of the Lorentzian dependence on the temperature was explained with the thermal excitation of Er 4f electrons and release of trapped charges in GaAs. The thermal excitation and release of charges consistently explained the characteristics of weak 4f luminescence in low- and high-temperature regions, respectively.

  7. Deep Levels in p-Type InGaAsN Lattice Matched to GaAs

    SciTech Connect (OSTI)

    Allerman, A.A.; Jones, E.D.; Kaplar, R.J.; Kurtz, S.R.; Kwon, D.; Ringel, S.A.

    1999-03-02T23:59:59.000Z

    Deep level transient spectroscopy (DLTS) measurements were utilized to investigate deep level defects in metal-organic chemical deposition (MOCVD)-grown unintentionally doped p-type InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the bandgap, with a dominant hole trap at E{sub v} + 0.10 eV. Post-growth annealing simplified the deep level spectra, enabling the identification of three distinct hole traps at 0.10 eV, 0.23 eV, and 0.48 eV above the valence band edge, with concentrations of 3.5 x 10{sup 14} cm{sup {minus}3}, 3.8 x 10{sup 14} cm{sup {minus}3}, and 8.2 x 10{sup 14} cm{sup {minus}3}, respectively. A direct comparison between the as-grown and annealed spectra revealed the presence of an additional midgap hole trap, with a concentration of 4 x 10{sup 14} cm{sup {minus}3} in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material quality and minority carrier properties after annealing. Of the four hole traps detected, only the 0.48 eV level is not influenced by annealing, suggesting this level may be important for processed InGaAsN devices in the future.

  8. Selfsimilar and fractal analysis of n-type delta-doped quasiregular GaAs quantum wells

    SciTech Connect (OSTI)

    Garca-Cervantes, H.; Rodrguez-Vargas, I. [Unidad Acadmica de Fsica, Universidad Autnoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac. (Mexico)

    2014-05-15T23:59:59.000Z

    We study the electronic structure of n-type delta-doped quantum wells in GaAs in which the multiple well system is built according to the Fibonacci sequence. The building blocks A and B correspond to delta-doped wells with impurities densities n{sub 2DA} and n{sub 2DB}, and the same well width. The Thomas-Fermi approximation, the semi-empirical sp{sub 3}s* tight-binding model including spin, the Surface Green Function Matching method and the Transfer Matrix approach were implemented to obtain the confining potential, the electronic structure and the selfsimilarity of the spectrum. The fragmentation of the electronic spectra is observed whenever the building blocks A and B interact and it increases as the difference of impurities density between A and B increases as well. The wave function of the first sate of the fragmented bands presents critical characteristics, this is, it is not a localized state nor a extended one as well as it has selfsimilar features. So, the quasiregular characteristics are preserved irrespective of the complexity of the system and can affect the performance of devices based on these structures.

  9. Seismic load-resisting capacity of plastered straw bale walls

    E-Print Network [OSTI]

    Hsiaw, Jennifer S. (Jennifer Sing-Yee)

    2010-01-01T23:59:59.000Z

    Straw bales have been incorporated into buildings for centuries, but only recently have they been explored in academic settings for their structural potential. Straw bale building is encountering a growing audience due to ...

  10. NMR relaxometry study of plaster mortar with polymer additives

    SciTech Connect (OSTI)

    Jumate, E.; Manea, D. [Technical University of Cluj-Napoca, Faculty of Civil Engineering. 15 C Daicoviciu Str., 400020, Cluj-Napoca (Romania)] [Technical University of Cluj-Napoca, Faculty of Civil Engineering. 15 C Daicoviciu Str., 400020, Cluj-Napoca (Romania); Moldovan, D.; Fechete, R. [Technical University of Cluj-Napoca, Department of Physics and Chemistry, 25 G. Baritiu Str., 400027, Cluj-Napoca (Romania)] [Technical University of Cluj-Napoca, Department of Physics and Chemistry, 25 G. Baritiu Str., 400027, Cluj-Napoca (Romania)

    2013-11-13T23:59:59.000Z

    The cement mixed with water forms a plastic paste or slurry which stiffness in time and finally hardens into a resistant stone. The addition of sand aggregates, polymers (Walocel) and/or calcium carbonate will modify dramatically the final mortar mechanic and thermal properties. The hydration processes can be observed using the 1D NMR measurements of transverse T{sub 2} relaxation times distributions analysed by a Laplace inversion algorithm. These distributions were obtained for mortar pasta measured at 2 hours after preparation then at 3, 7 and 28 days after preparation. Multiple components are identified in the T{sub 2} distributions. These can be associated with the proton bounded chemical or physical to the mortar minerals characterized by a short T{sub 2} relaxation time and to water protons in pores with three different pore sizes as observed from SEM images. The evaporation process is faster in the first hours after preparation, while the mortar hydration (bonding of water molecules to mortar minerals) can be still observed after days or months from preparation. Finally, the mechanic resistance was correlated with the transverse T{sub 2} relaxation rates corresponding to the bound water.

  11. Gypsum, Colorado: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation,Ohio:Greer County is a county inAl.,20454°,

  12. Optical and digital GaAs technologies for signal-processing applications; Proceedings of the Meeting, Orlando, FL, Apr. 16-18, 1990

    SciTech Connect (OSTI)

    Bendett, M.P.; Butler, D.H., Jr.; Prabhakar, A.; Yang, A.; (Honeywell, Inc., Minneapolis, MN; Booz, Allen and Hamilton, Inc., Bethesda, MD; DARPA, Arlington, VA)

    1990-01-01T23:59:59.000Z

    Practical problems that need to be solved for the introduction of optical modules into processing systems are reviewed. Some papers deal with the state of the art in such key devices as Bragg cells, spatial light modulators, and fast CCDs. Issues unique to optical packaging are also highlightened. New architectures to enable real-time operations are demonstrated, and optical interconnects for parallel processors are discussed. Particular attention is given to the status and operational advantages of government-sponsored efforts to upgrade existing military systems with digital GaAs signal processors and the state of the art in computer-aided design and advanced system architectures.

  13. Final Technical Progress Report: High-Efficiency Low-Cost Thin-Film GaAs Photovoltaic Module Development Program; July 14, 2010 - January 13, 2012

    SciTech Connect (OSTI)

    Mattos, L.

    2012-03-01T23:59:59.000Z

    This is the final technical progress report of the High-Efficiency Low-Cost Thin-Film GaAs Photovoltaic Module Development Program. Alta Devices has successfully completed all milestones and deliverables established as part of the NREL PV incubator program. During the 18 months of this program, Alta has proven all key processes required to commercialize its solar module product. The incubator focus was on back end process steps directed at conversion of Alta's high quality solar film into high efficiency 1-sun PV modules. This report describes all program deliverables and the work behind each accomplishment.

  14. Infrared spectroscopy of lattice vibrations in ZnTe/CdTe superlattices with quantum dots on the GaAs substrate with the ZnTe buffer layer

    SciTech Connect (OSTI)

    Kozyrev, S. P. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: skozyrev@sci.lebedev.ru

    2009-03-15T23:59:59.000Z

    The results of the analysis of the infrared lattice reflectance spectra of multiperiod ZnTe/CdTe superlattices with CdTe quantum dots are reported. The samples are grown by molecular beam epitaxy on the GaAs substrate with the ZnTe buffer layer. Due to the large number of periods of the superlattices, it is possible to observe CdTe-like vibration modes in the quantum dots, i.e., the dislocation-free stressed islands formed during the growth due to relaxation of elastic stresses between the ZnTe and CdTe layers are markedly different in their lattice parameters. From the frequency shifts of the CdTe- and ZnTe-like vibration modes with respect to the corresponding modes in the unstressed materials, it is possible to estimate the level of elastic stresses.

  15. Critical size for the generation of misfit dislocations and their effects on electronic properties in GaAs nanosheets on Si substrate

    SciTech Connect (OSTI)

    Yuan, Zaoshi [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States) [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025 (United States); Shimamura, Kohei [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States) [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Shimojo, Fuyuki [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States) [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Nakano, Aiichiro [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States)] [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States)

    2013-08-21T23:59:59.000Z

    While nanowires and nanosheets (NSs) grown on lattice-mismatched substrates have a number of promising technological applications such as solar cells, generation of misfit dislocations (MFDs) at their interfaces is a major concern for the efficiency of these devices. Here, combined molecular-dynamics and quantum-mechanical simulations are used to study MFDs at the interface between a GaAs NS and a Si substrate. Simulation results show the existence of a critical NS thickness, below which NSs are grown free of MFDs. The calculated critical thickness value is consistent with available experimental observations. Charge transfer at the MFD core is found to modify the electronic band profile at the GaAs/Si interface significantly. These effects should have profound impacts on the efficiency of lattice-mismatched NS devices.

  16. Repetition of the shape of the ultrafast self-modulation of the optical absorption spectrum upon varying the energy of pulse of GaAs pumping

    SciTech Connect (OSTI)

    Ageeva, N. N.; Bronevoi, I. L., E-mail: bil@cplire.ru; Zabegaev, D. N.; Krivonosov, A. N. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)

    2010-10-15T23:59:59.000Z

    Ultrafast self-modulation of the fundamental optical absorption emerges during intense picosecond optical pumping of GaAs and, according to the main assumption, reflects self-oscillations of depletion of electron populations in the conduction band. In this study, the quantitatively confirmed explanation of previously experimentally found cyclic repetition of the form of ultrafast self-modulation of the absorption spectrum upon varying the energy of the pumping pulse and fixed delay between pumping and probing (the measurement of absorption) is given. Repetition of the shape is explained by varying the phase of self-oscillations of the optical absorption. The explanation is based on the previously found experimentally dependence of the frequency of self-oscillations of absorption on the pumping energy. Therefore, this is also a new confirmation of the mentioned dependence (which satisfactorily coincides with a similar calculated dependence of the frequency of self-oscillations of depletion of populations).

  17. Polarity driven simultaneous growth of free-standing and lateral GaAsP epitaxial nanowires on GaAs (001) substrate

    SciTech Connect (OSTI)

    Sun, Wen; Xu, Hongyi [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia)] [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia); Guo, Yanan [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia) [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Gao, Qiang; Hoe Tan, Hark; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)] [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Zou, Jin, E-mail: j.zou@uq.edu.au [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia) [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia); Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia QLD 4072 (Australia)

    2013-11-25T23:59:59.000Z

    Simultaneous growth of ?111?{sub B} free-standing and [110] lateral GaAsP epitaxial nanowires on GaAs (001) substrates were observed and investigated by electron microscopy and crystallographic analysis. It was found that the growth of both free-standing and lateral ternary nanowires via Au catalysts was driven by the fact that Au catalysts prefer to maintain low-energy (111){sub B} interfaces with surrounding GaAs(P) materials: in the case of free-standing nanowires, Au catalysts maintain (111){sub B} interfaces with their underlying GaAsP nanowires; while in the case of lateral nanowires, each Au catalyst remain their side (111){sub B} interfaces with the surrounding GaAs(P) material during the lateral nanowire growth.

  18. Co doping enhanced giant magnetocaloric effect in Mn{sub 1-x}Co{sub x}As films epitaxied on GaAs (001)

    SciTech Connect (OSTI)

    Xu, P. F.; Nie, S. H.; Meng, K. K.; Wang, S. L.; Chen, L.; Zhao, J. H. [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2010-07-26T23:59:59.000Z

    A giant magnetocaloric effect was found in series of Mn{sub 1-x}Co{sub x}As films epitaxied on GaAs (001). The maximum magnetic entropy change caused by a magnetic field of 4 T is as large as 25 J/kg K around room temperature, which is about twice the value of pure MnAs film. The observed small thermal hysteresis is more suitable for practical application. Growing of layered Mn{sub 1-x}Co{sub x}As films with Co concentration changing gradually may draw layered active magnetic regenerator refrigerators closer to practical application. Our experimental result may provide the possibility for the combination of magnetocaloric effect and microelectronic circuitry.

  19. Structural properties of Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} topological insulators grown by molecular beam epitaxy on GaAs(001) substrates

    SciTech Connect (OSTI)

    Liu, X.; Leiner, J.; Dobrowolska, M.; Furdyna, J. K. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Smith, D. J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Fan, J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287 (United States); Zhang, Y.-H. [Center for Photonics Innovation, Arizona State University, Tempe, Arizona 85287 (United States); School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Cao, H.; Chen, Y. P. [Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States); Kirby, B. J. [Center for Neutron Research, NIST, Gaithersburg, Maryland 20899 (United States)

    2011-10-24T23:59:59.000Z

    Thin films of Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} have been grown on deoxidized GaAs(001) substrates using molecular beam epitaxy. Cross-sectional transmission electron microscopy established the highly parallel nature of the Te(Se)-Bi-Te(Se)-Bi-Te(Se) quintuple layers deposited on the slightly wavy GaAs substrate surface and the different crystal symmetries of the two materials. Raman mapping confirmed the presence of the strong characteristic peaks reported previously for these materials in bulk form. The overall quality of these films reveals the potential of combining topological insulators with ferromagnetic semiconductors for future applications.

  20. Didcot B, launch platform for V94.3A

    SciTech Connect (OSTI)

    NONE

    1996-11-01T23:59:59.000Z

    National Power`s fourth combined cycle station at Didcot is now commissioning the first 660 MW block. But at the end of the year, the first examples of Siemens` advanced 240 MW gas turbine, Model V94.3A, will start simple cycle operation pending completion of the steam cycle. National Power`s clean-up strategy has seen emissions of SO{sub 2} and NO{sub x} halved, and CO{sub 2} emissions reduced by 30%. At Drax, a long-term contract with British Gypsum has ensured a market for the gypsum produced in the FGD unit to make plaster board. 3 figs., 1 tab.

  1. Wafer Bonding and Epitaxial Transfer of GaSb-based Epitaxy to GaAs for Monolithic Interconnection of Thermophotovoltaic Devices

    SciTech Connect (OSTI)

    C.A. Wang; D.A. Shiau; P.G. Murphy; P.W. O'brien; R.K. Huang; M.K. Connors; A.C. Anderson; D. Donetsky; S. Anikeev; G. Belenky; D.M. Depoy; G. Nichols

    2003-06-16T23:59:59.000Z

    GaInAsSb/AlGaAsSb/InAsSb/GaSb epitaxial layers were bonded to semi-insulating GaAs handle wafers with SiO{sub x}/Ti/Au as the adhesion layer for monolithic interconnection of thermophotovoltaic (TPV) devices. Epitaxial transfer was completed by removal of the GaSb substrate, GaSb buffer, and InAsSb etch-stop layer by selective chemical etching. The SiO{sub x}/TiAu provides not only electrical isolation, but also high reflectivity and is used as an internal back-surface reflector. Characterization of wafer-bonded epitaxy by high-resolution x-ray diffraction and time-decay photoluminescence indicates minimal residual stress and enhancement in optical quality. 0.54-eV GaInAsSb cells were fabricated and monolithically interconnected in series. A 10-junction device exhibited linear voltage building with an open-circuit voltage of 1.8 V.

  2. Spin decoherence in n-type GaAs: The effectiveness of the third-body rejection method for electron-electron scattering

    SciTech Connect (OSTI)

    Marchetti, Gionni, E-mail: gionnimarchetti@gmail.com; Hodgson, Matthew, E-mail: matthew.hodgson@york.ac.uk; D'Amico, Irene, E-mail: irene.damico@york.ac.uk [Department of Physics, University of York, York, Heslington YO10 5DD (United Kingdom)

    2014-10-28T23:59:59.000Z

    We study the spin decoherence in n-type bulk GaAs for moderate electronic densities at room temperature using the Ensemble Monte Carlo method. We demonstrate that a technique called third-body rejection method devised by B. K. Ridley, J. Phys. C: Solid State Phys. 10, 1589 (1977) can be successfully adapted to Ensemble Monte Carlo method and used to tackle the problem of the electron-electron contribution to spin decoherence in the parameter region under study, where the electron-electron interaction can be reasonably described by a Yukawa potential. This scattering technique is employed in a doping region where one can expect that multiple collisions may play a role in carrier dynamics. By this technique, we are able to calculate spin relaxation times which are in very good agreement with the experimental results found by Oertel et al., Appl. Phys. Lett. 93, 13 (2008). Through this method, we show that the electron-electron scattering is overestimated in Born approximation, in agreement with previous results obtained by C. A. Kukkonen and H. Smith, Phys. Rev. B 8, 4601 (1973).

  3. IR spectroscopy of lattice vibrations and comparative analysis of the ZnTe/CdTe quantum-dot superlattices on the GaAs substrate and with the ZnTe and CdTe buffer layers

    SciTech Connect (OSTI)

    Kozyrev, S. P. [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation)], E-mail: skozyrev@sci.lebedev.ru

    2009-07-15T23:59:59.000Z

    A comparative analysis of multiperiod ZnTe/CdTe superlattices with the CdTe quantum dots grown by molecular beam epitaxy on the GaAs substrate with the ZnTe and CdTe buffer layers is carried out. The elastic-stress-induced shifts of eigenfrequencies of the modes of the CdTe- and ZnTe-like vibrations of materials forming similar superlattices but grown on different buffer ZnTe and CdTe layers are compared. The conditions of formation of quantum dots in the ZnTe/CdTe superlattices on the ZnTe and CdTe buffer layers differ radically.

  4. Green (In,Ga,Al)P-GaP light-emitting diodes grown on high-index GaAs surfaces

    SciTech Connect (OSTI)

    Ledentsov, N. N., E-mail: nikolay.ledentsov@v-i-systems.com; Shchukin, V. A. [VI Systems GmbH, Hardenbergstr. 7, Berlin D-10623 (Germany); Lyytikinen, J.; Okhotnikov, O. [Optoelectronics Research Centre, Tampere University of Technology, Tampere FI-33720 (Finland); Shernyakov, Yu. M.; Payusov, A. S.; Gordeev, N. Yu.; Maximov, M. V. [A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Schlichting, S.; Nippert, F.; Hoffmann, A. [Institut fr Festkrperphysik, Technische Universitt Berlin, Hardenbergstrasse 36, Berlin D-10623 (Germany)

    2014-11-03T23:59:59.000Z

    We report on green (550560?nm) electroluminescence (EL) from (Al{sub 0.5}Ga{sub 0.5}){sub 0.5}In{sub 0.5}P-(Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P double p-i-n heterostructures with monolayer-scale GaP insertions in the cladding layers and light-emitting diodes based thereupon. The structures are grown side-by-side on high-index and (100) GaAs substrates by molecular beam epitaxy. At moderate current densities (?500?A/cm{sup 2}), the EL intensity of the structures is comparable for all substrate orientations. Opposite to the (100)-grown strictures, the EL spectra of (211) and (311)-grown devices are shifted towards shorter wavelengths (?550?nm at room temperature). At high current densities (>1?kA/cm{sup 2}), a much higher EL intensity is achieved for the devices grown on high-index substrates. The integrated intensity of (311)-grown structures gradually saturates at current densities above 4?kA/cm{sup 2}, whereas no saturation is revealed for (211)-grown structures up to the current densities above 14?kA/cm{sup 2}. We attribute the effect to the surface orientation-dependent engineering of the GaP band structure, which prevents the escape of the nonequilibrium electrons into the indirect conduction band minima of the p-doped (Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P cladding layers.

  5. Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers

    SciTech Connect (OSTI)

    Bae, K. W.; Mohamed, Mohd Ambri; Jung, D. W.; Otsuka, N. [School of Materials Science Japan Advanced Institute of Science and Technology Asahidai 1-1, Nomishi, Ishikawa 923-1292 (Japan)

    2011-04-01T23:59:59.000Z

    Beryllium-doped GaAs layers grown at low temperatures by molecular-beam epitaxy contain localized spins associated with unpaired sp electrons of As{sub Ga}{sup +} ions. Interactions of these localized spins are investigated by measuring the magnetization with a superconducting quantum interference device and the peak-to-peak width of electron paramagnetic resonance (EPR) spectra for samples with different spin concentrations ranging from 3 x 10{sup 18} to 2.0 x 10{sup 19} cm{sup -3}. The results show that localized spins in this material antiferromagnetically interact on each other via direct exchange. From the analysis of the temperature dependence and field dependence of the magnetization on the basis of the Curie-Weiss law and the molecular-field approximation, exchange energy of each sample was derived. The dependence of the exchange energy on the concentration of localized spins is reasonably explained by a model of direct exchange, which results from the overlapping of wave functions of unpaired electrons at As{sub Ga}{sup +} ions. The peak-to-peak width of EPR spectra increases with an increase in the spin concentration at low temperatures, whereas it decreases with an increase in the temperature for samples with high spin concentrations. These EPR results also show that significant exchange interactions indeed occur between localized spins in this material. These effects of direct exchange interactions between localized spins can clearly be observed at their average distances of around 4 nm, which implies a considerably large spatial extension of the wave function of an unpaired sp electron around an As{sub Ga}{sup +} ion.

  6. RELATIVE ATTENUATION CHARACTERISTICS OF SOME SHIELDING MATERIALS FOR PuB NEUTRONS

    E-Print Network [OSTI]

    Bringham, P.S.

    2010-01-01T23:59:59.000Z

    1: Polyethylene Water Spodumene-gypsum Gypsum, wet and dryconstituents of the spodumene-gypsum, and gypsum shields.SPODUMENK,GYPSUM SHIELD 30% Spodumene by weight 40% Gypsum

  7. Leaning, Merging, Overlapping, Translucently

    E-Print Network [OSTI]

    Bank, Rachel

    2013-01-01T23:59:59.000Z

    Installation view of poured plaster sculptures with coloredof light spills. 35 F. 14: Poured plaster36 F. 15: Plaster crumple

  8. Molecular beam epitaxial growth of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} topological insulators on GaAs (111) substrates: a potential route to fabricate topological insulator p-n junction

    SciTech Connect (OSTI)

    Zeng, Zhaoquan; Morgan, Timothy A.; Li, Chen; Hirono, Yusuke; Hu, Xian; Hawkridge, Michael E.; Benamara, Mourad; Salamo, Gregory J. [Arkansas Institute for Nanoscale Material Sciences and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States)] [Arkansas Institute for Nanoscale Material Sciences and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); Fan, Dongsheng; Yu, Shuiqing [Arkansas Institute for Nanoscale Material Sciences and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States) [Arkansas Institute for Nanoscale Material Sciences and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); Department of Electrical Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); Zhao, Yanfei [International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871 (China)] [International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871 (China); Lee, Joon Sue [The Center for Nanoscale Science and Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States)] [The Center for Nanoscale Science and Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States); Wang, Jian [International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871 (China) [International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871 (China); The Center for Nanoscale Science and Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States); Wang, Zhiming M. [Arkansas Institute for Nanoscale Material Sciences and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States) [Arkansas Institute for Nanoscale Material Sciences and Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China)

    2013-07-15T23:59:59.000Z

    High quality Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, X-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111) substrate is better than a vicinal substrate to provide high quality Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} films. Hall and magnetoresistance measurements indicate that p type Sb{sub 2}Te{sub 3} and n type Bi{sub 2}Te{sub 3} topological insulator films can be directly grown on a GaAs (111) substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.

  9. Origins of Eponymous Orthopaedic Equipment

    E-Print Network [OSTI]

    Meals, Clifton; Wang, Jeffrey

    2010-01-01T23:59:59.000Z

    Fig. 6). He found that plasters manufactured by Johnson andoxide to neutralize the plasters noxious effect. Unnasseveral advantages over plaster casting, namely, freedom in

  10. Is Gypsum Application Beneficial to Soil? Francisco J. Arriaga

    E-Print Network [OSTI]

    Balser, Teri C.

    ). · Response to calcium application unlikely even in soils testing low or very low, except when growing S demand (alfalfa, canola and brassicas), in sandy soils and soils low in organic matter. · Soils with low or medium potential for sulfate retention (sands and loamy sands), and with no recent manure applications

  11. Gypsum and Polyacrylamide Soil Amendments Used With High Sodium Wastewater

    E-Print Network [OSTI]

    Gardiner, Duane

    Using wastewater for irrigation of crops represents an attractive alternative to disposal. Typically, municipal wastewaters are high in sodium, and the resulting high sodium absorption ratio (SAR) alters the soil structure making it more impermeable...

  12. Utilization of by-product gypsum in construction

    E-Print Network [OSTI]

    Stephenson, Angela Lorraine

    1987-01-01T23:59:59.000Z

    . Neutralization processes with NaOH and Ca(OH) & were studied and stabilization with commercial grade types of portland cement and fly ash was investigated (after different curing periods) to compare relative strengths as applied to road construction.... For phosphogypsum stabilized by portland cement, initial and intermediate stages of strength development obtained for the material, cured for 3 and 7 days at approximate pH levels of 4, 6, and 8 and cement contents of 34 and 64, yielded strengths which increase...

  13. Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum

    SciTech Connect (OSTI)

    Hensman, Carl, E., P.h.D; Baker, Trevor

    2008-06-16T23:59:59.000Z

    Frontier Geosciences (Frontier; FGS) proposed for DOE Grant No. DE-FG02-07ER84669 that mercury control could be achieved in a wet scrubber by the addition of an amendment to the wet-FGD scrubber. To demonstrate this, a bench-scale scrubber and synthetic flue-gas supply was designed to simulate the limestone fed, wet-desulfurization units utilized by coal-fired power plants. Frontier maintains that the mercury released from these utilities can be controlled and reduced by modifying the existing equipment at installations where wet flue-gas desulfurization (FGD) systems are employed. A key element of the proposal was FGS-PWN, a liquid-based mercury chelating agent, which can be employed as the amendment for removal of all mercury species which enter the wet-FGD scrubber. However, the equipment design presented in the proposal was inadequate to demonstrate these functions and no significant progress was made to substantiate these claims. As a result, funding for a Phase II continuation of this work will not be pursued. The key to implementing the technology as described in the proposal and report appears to be a high liquid-to-gas ratio (L/G) between the flue-gas and the scrubber liquor, a requirement not currently implemented in existing wet-FGD designs. It may be that this constraint can be reduced through parametric studies, but that was not apparent in this work. Unfortunately, the bench-scale system constructed for this project did not function as intended and the funds and time requested were exhausted before the separation studies could occur.

  14. Evidence of a bacterial carbonate coating on plaster samples subjected to the Calcite Bioconcept biomineralization technique

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    made of concrete as well as historic buildings made of stone or brick. These porous materials on concrete and on limestone samples in an aqueous environment. However, the carbonate production was measured and biological) [1, 2]. In all cases, water transfer within the whole volume of the porous media is the common

  15. This form is interactive --complete electronically and print! Environmental Health & Safety Service Building SER 202 304 E. 24th St. Austin, Texas 78712-0297

    E-Print Network [OSTI]

    -containing materials Drywall and joint compound Insulation, wall Insulation, ceiling Plaster, wall Plaster, ceiling

  16. Impact of stress relaxation in GaAsSb cladding layers on quantum dot creation in InAs/GaAsSb structures grown on GaAs (001)

    SciTech Connect (OSTI)

    Bremner, S. P. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052 (Australia)] [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052 (Australia); Ban, K.-Y.; Faleev, N. N.; Honsberg, C. B. [School of Electrical, Computer and Energy Engineering, Ira A. Fulton Schools of Engineering, Solar Power Lab, Arizona State University, Tempe, Arizona 85287 (United States)] [School of Electrical, Computer and Energy Engineering, Ira A. Fulton Schools of Engineering, Solar Power Lab, Arizona State University, Tempe, Arizona 85287 (United States); Smith, D. J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)] [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

    2013-09-14T23:59:59.000Z

    We describe InAs quantum dot creation in InAs/GaAsSb barrier structures grown on GaAs (001) wafers by molecular beam epitaxy. The structures consist of 20-nm-thick GaAsSb barrier layers with Sb content of 8%, 13%, 15%, 16%, and 37% enclosing 2 monolayers of self-assembled InAs quantum dots. Transmission electron microscopy and X-ray diffraction results indicate the onset of relaxation of the GaAsSb layers at around 15% Sb content with intersected 60 dislocation semi-loops, and edge segments created within the volume of the epitaxial structures. 38% relaxation of initial elastic stress is seen for 37% Sb content, accompanied by the creation of a dense net of dislocations. The degradation of In surface migration by these dislocation trenches is so severe that quantum dot formation is completely suppressed. The results highlight the importance of understanding defect formation during stress relaxation for quantum dot structures particularly those with larger numbers of InAs quantum-dot layers, such as those proposed for realizing an intermediate band material.

  17. Don't Say Goodnight

    E-Print Network [OSTI]

    Perez, Ryan Mark

    2012-01-01T23:59:59.000Z

    2012 3 reliefs cast in plaster and cement tint. 422012 3 reliefs cast in plaster and cement tint. 422012 3 reliefs cast in plaster and cement tint. 42

  18. Between Victory and Defeat: Framing the Fallen Warrior in Fifth-Century Athenian Art

    E-Print Network [OSTI]

    Arrington, Nathan Todd

    2010-01-01T23:59:59.000Z

    relief. Villa Albani 985 (plaster cast in Bonn, Akademischescoated with hydraulic plaster. Alexandri, O. 1971 ArchDeltof unworked stones and plaster. Alexandri, O. 1976 ArchDelt

  19. G-protein mediated trafficking of inwardly rectifying potassium channels

    E-Print Network [OSTI]

    Boyer, Stephanie B.

    2008-01-01T23:59:59.000Z

    Nature 436:78-86. Plaster Nm TRT- FMCSBSTADMRISTBEBRCJ (and cardiac arrhythmias (Plaster et al, 2001). Over 20Neurosci 21:1189-1202. Plaster Nm TRT-FMCSBSTADMRISTBEBRCJ (

  20. Treatment of Hidradenitis Supprurativa Associated Pain with Nonsteroidal Anti-Inflammatory Drugs, Acetaminophen, Celecoxib, Gabapentin, Pegabalin, Duloxetine, and Venlafaxine

    E-Print Network [OSTI]

    Scheinfeld, Noah

    2013-01-01T23:59:59.000Z

    Z.Pregabalin, the lidocaine plaster and duloxetine inlidocaine-medicated plaster vs other relevant interventionslignocaine) medicated plaster in comparison with pregabalin

  1. Between Dada and Architecture: Marcel Janco in Zurich and Bucharest, 1916-1939

    E-Print Network [OSTI]

    Avivi, Adele

    2012-01-01T23:59:59.000Z

    Janco, White on White, 1917, Plaster relief. Figure 1.8.Flower Geometry, 1917, plaster relief painted in gouache.3( Lock), 1917, painted plaster relief. Photograph: Dada no.

  2. Mud-Brick Architecture

    E-Print Network [OSTI]

    Emery, Virginia L.

    2011-01-01T23:59:59.000Z

    this layer with mud plaster (fig. 2; Arnold 2003: 47;with reeds coated in mud plaster, were the source of many ofprehistoric period, mud plaster increasingly was employed

  3. La muralla de Chichn : excavations of a Maya site perimeter wall

    E-Print Network [OSTI]

    Hahn, Lauren D.

    2010-01-01T23:59:59.000Z

    or permanence (i.e. no plaster facing or other stabilizingfine masonry, covered with plaster, and painted, in contrastthrough adornment, including plaster facing and the use of

  4. The Paradoxical Persistence of James Earle Fraser's End of the Trail: Nostalgia, Souvenirs, and the Politics of Pictorial Representation

    E-Print Network [OSTI]

    Borrman, Kristina

    2012-01-01T23:59:59.000Z

    End of the Trail, 1915, plaster sculpture. National CowboyProctor. Cowboy, 1893, plaster sculpture. ColumbianThe American Pioneer, 1915, plaster sculpture. Mooney Grove

  5. Experiencing Maya Palaces: Royal Power, Space, and Architecture at Holmul, Guatemala

    E-Print Network [OSTI]

    Mongelluzzo, Ryan

    2011-01-01T23:59:59.000Z

    headquarters. The stucco and plaster facades of ancient Mayafrom the formerly white plaster (Schele 1985:37). The colorwere found, all beneath plaster floors, and all children.

  6. The Journal of John Waldie Theatre Commentaries, 1799-1830: no. 26 [Journal 37] December 9, 1816-February 16, 1817. Part 3

    E-Print Network [OSTI]

    Burwick, Frederick

    2008-01-01T23:59:59.000Z

    design. in models of plaster. Some dancing Nymphs. Numbersstatue, but only in plaster, of Napoleon: the original iswere some good models in plaster, St. John the Baptist, and

  7. Interaction between alpha-calcium sulfate hemihydrate and superplasticizer from the point of adsorption characteristics, hydration and hardening process

    SciTech Connect (OSTI)

    Guan Baohong; Ye Qingqing; Zhang Jiali; Lou Wenbin [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China); Wu Zhongbiao, E-mail: zbwu@zju.edu.c [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China)

    2010-02-15T23:59:59.000Z

    Superplasticizers (SPs), namely sulfonated melamine formaldehyde (SMF) and polycarboxylate (PC), were independently admixed with alpha-calcium sulfate hemihydrate based plaster to improve the material's performance. SMF and PC gave, respectively, 38% and 25% increases in the 2 h bending strength at the optimum dosages of 0.5 wt.% and 0.3 wt.%, which are determined essentially by the maximum water-reducing efficiency. The peak shift of binding energy of Ca2p{sub 3/2} detected by X-ray photoelectron spectroscopy (XPS) suggests that SPs are chemically adsorbed on gypsum surface. A careful examination of the strength development of set plaster allowed the hydration and hardening process to be divided roughly into five stages. SMF accelerates early hydration, while PC decelerates it. Both SPs allowed similar maximum water reductions, giving a more compact structure and a decrease in total pore volume and average pore diameter, and thus leading to higher strengths in the hardened plasters with SPs.

  8. Perception and Value of the Fresco in the Bronze Age Aegean

    E-Print Network [OSTI]

    Giffin, Sarah J

    2011-01-01T23:59:59.000Z

    directly onto wet lime plaster, was distinctly Aegean andof pigment onto dry plaster for only a portion ofthe fresco due to the plasters drying too quickly. 8 Thus,

  9. Holographic interferometry study of the dissolution and diffusion of gypsum in Jean Colombani

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and Wilde, 1971) with a Nernst-Hartley equation from the tracer diffusivity of the ions (Jeschke et al

  10. Remediation of brine-contaminated soil using calcium nitrate, gypsum, and straw.

    E-Print Network [OSTI]

    Nielsen, Jennifer I.

    2013-01-01T23:59:59.000Z

    ??Salt-affected soils from point source brine contamination are common in the active oil field in SE Saskatchewan. A remediation process that included dewatering by sub-surface (more)

  11. The detrimental effects of salinity on rooting of coleus cuttings and their alleviation with gypsum

    E-Print Network [OSTI]

    Janssen, Antonius Hendrick

    1981-01-01T23:59:59.000Z

    . The effect of NaC1 on root number and color intensity of the foliage were not altered by the addition of CaSO . The beneficial effects of CaS04 cou1d not be demonstrated in a peat-styrafoam medium. Acknowledgements I would like to express my sincere... Ca/Na ratios for the NaC1:Ca504 solutions 5 Electrical conductivities (E. C. ) of 2 KNO solutions with i ncreasing CaS04 concent/ations 6 The effects of pH and peat extract on rooting of 'Big Red' cuttings . Page 13 15 44 45 56 LIST...

  12. Magnetic resonance studies of cement based materials in inhomogeneous magnetic fields

    SciTech Connect (OSTI)

    Boguszynska, Joanna [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, Poznan (Poland); Brown, Marc C.A. [School of Physical Sciences, University of Kent, Canterbury, Kent, CT2 7NR (United Kingdom); McDonald, Peter J. [School of Electronics and Physical Sciences, University of Surrey, Surrey, GU2 7XH (United Kingdom)]. E-mail: p.mcdonald@surrey.ac.uk; Mitchell, Jonathan [School of Electronics and Physical Sciences, University of Surrey, Surrey, GU2 7XH (United Kingdom); Mulheron, Mike [School of Engineering, University of Surrey, Surrey, GU2 7XH (United Kingdom); Tritt-Goc, Jadwiga [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, Poznan (Poland); Verganelakis, Dimitris A. [Department of Chemical Engineering, University of Cambridge, Cambridge, CB2 3RA (United Kingdom)

    2005-10-01T23:59:59.000Z

    Single-sided magnets give hope that Nuclear Magnetic Resonance (NMR) might in future be used for in situ characterisation of hydration and water transport in the surface layers of concrete slabs. Towards that end, a portable NMR-MOUSE (MObile Universal Surface Explorer) has been used to follow the hydration of gypsum based plaster, a Portland cement paste and concrete mortar. The results compare favourably to those obtained using a standard laboratory bench-top spectrometer. Further, stray field imaging (STRAFI) based methods have been used with embedded NMR detector coils to study water transport across a mortar/topping interface. The measured signal amplitudes are found to correlate with varying sample conditions.

  13. Separation of flue-gas scrubber sludge into marketable products. Second quarterly technical progress report, December 1, 1993--February 28, 1994 (Quarter No. 2)

    SciTech Connect (OSTI)

    Kawatra, S.K.; Eisele, T.C.

    1994-03-01T23:59:59.000Z

    To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of This sludge is a result of reacting limestone with sulfur dioxide to precipitate calcium sulfite and calcium sulfate. It consists of calcium sulfite (CaSO{sub 3}{lg_bullet}0.5H{sub 2}0), gypsum (CaSO{sub 4}{lg_bullet}2H{sub 2}0), and unreacted limestone (CaCO{sub 3}) or lime (Ca(OH){sub 2}), with miscellaneous objectionable impurities such as iron oxides; silica; and magnesium, sodium, and potassium oxides or salts. Currently, the only market for scrubber sludge is for manufacture of gypsum products, such as wallboard and plaster, and for cement. However, the quality of the raw sludge is often not high enough or consistent enough to satisfy manufacturers, and so the material is difficult to sell. This project is developing a process that can produce a high-quality calcium sulfite or gypsum product while keeping process costs low enough that the material produced will be competitive with that from other, more conventional sources. This purification will consist of minimal-reagent froth flotation, using the surface properties of the particles of unreacted limestone to remove them and their associated impurities from the material, leaving a purified gypsum or calcium sulfite product. The separated limestone will be a useful by-product, as it can be recycled to the scrubber, thus boosting the limestone utilization and improving process efficiency. Calcium sulfite will then be oxidized to gypsum, or separated as a salable product in its own right from sludges where it is present in sufficient quantity. The main product of the process will be either gypsum or calcium sulfite, depending on the characteristics of the sludge being processed. These products will be sufficiently pure to be easily marketed, rather that being landfilled.

  14. A Study of the Filling of Wall Cavities With Retrofit Wall Insulation.

    SciTech Connect (OSTI)

    Flores, Joseph A.; Grill, Alan R.

    1988-08-01T23:59:59.000Z

    The Pacific Northwest Power Marketing Agency, the Bonneville Power Administration (BPA), conducted a retrofit wall insulation study to determine the effects of various obstructions within a wall cavity, where voids are likely to occur, and preferred filling methods and material types. The insulation test structure was composed of four 8-foot /times/ 12-foot walls, and was built using standard construction practices. The inside walls were clear plastic glazing, instead of gypsum board, to enable viewing of the filling process. A total of eight tests were performed: four cellulose, two rockwool, and two fiberglass. One- and two-hole filling methods were observed. All insulations were found to perform in the same basic manner with all experiencing the same problem areas. Common installer problems were empty spaces at the tops of cavities and missed cavities, especially above headers. Wiring and lath and plaster consistently caused reduced insulation densities in cavities. The problems with wiring, lath and plaster, and other features in the wall cavities were avoided with the use of a filler tube. The filler tube also provided a more consistent fill along the length of the entire cavity. 2 figs., 3 tabs.

  15. materials analysis of inorganic, organic, and bioma-terials. See ELECTRON MICROSCOPE.

    E-Print Network [OSTI]

    Anderson, Peter M.

    28 Plaster materials analysis of inorganic, organic, and bioma- terials. See ELECTRON MICROSCOPE: The next chip-scale technology, Mater. Today, 9:20­27, 2006. Plaster A plastic mixture of solids and water plaster is also used in the industry to designate plaster of paris. Plaster is usually applied in one

  16. Separation of the components of flue-gas scrubber sludge by froth flotation

    SciTech Connect (OSTI)

    Kawatra, S.K.; Eisele, T.C. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering

    1995-12-31T23:59:59.000Z

    To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of. Currently, the major markets for scrubber sludge are for manufacture of gypsum products, such as wallboard and plaster, and for cement. However, the quality of the raw sludge is often not high enough or consistent enough to satisfy manufacturers, and so the material is difficult to sell. Other markets, such as paper manufacture and plastics fillers, have even more stringent quality requirements and will not accept raw sludge at all. In the work described in this paper, several reagents have been examined to determine their ability to selectively improve the flotation of the unreacted limestone contaminant away from the desirable products (calcium sulfite and gypsum). The most success has been achieved using a cationic collector, which shows a higher selectivity between calcium sulfite and calcium carbonate than do the anionic collectors that were studied.

  17. Archaism

    E-Print Network [OSTI]

    Kahl, Jochem

    2010-01-01T23:59:59.000Z

    UEE 2010 Figure 7. Late plaster casts of Old Kingdom reliefsevidence, in the form of late plaster casts of Old KingdomModels Figure 7. Late plaster casts of Old Kingdom reliefs

  18. THE INFLUENCE OF CURRENT ON THE ADHESIVE POTENTIAL, DENSITY AND ABUNDANCE OF THE MAGNIFICENT SEA ANEMONE (HETERACTIS MAGNIFICA) IN MOOREA, FRENCH POLYNESIA

    E-Print Network [OSTI]

    Lewis, Caroline A Ms.

    2012-01-01T23:59:59.000Z

    water current at each site, the plaster of Paris clod cardmade from the same batch of plaster and were allowed to dryOnce set in the field, each plaster was tied to a rock using

  19. The civic forum in ancient Israel : the form, function, and symbolism of city gates

    E-Print Network [OSTI]

    Frese, Daniel Allan

    2012-01-01T23:59:59.000Z

    of a small strip of lime plaster flooring found inside the 4the other half had a lime plaster finish (Ussishkin, Areaa few patches of lime plaster were found on top of the

  20. Humboldt-Universitt zu Berlin Explore it!

    E-Print Network [OSTI]

    Freytag, Johann-Christoph

    and go upstairs to the first floor. 7. PLASTER CASTINGS OF THE WINCKELMANN INSTITUTE Some plaster plaster casting collection of original ancient Greek and Roman sculptures. After the extensions had been

  1. Underfloor vs. overhead: a comparative analysis of air distribution systems using the EnergyPlus simulation software

    E-Print Network [OSTI]

    Daly, A.

    2006-01-01T23:59:59.000Z

    REGULAR, E8 - 5 / 8 IN PLASTER OR GYP BOARD, ! - NameSouthWall, E8 - 5 / 8 IN PLASTER OR GYP BOARD; CONSTRUCTION,NorthWall, E8 - 5 / 8 IN PLASTER OR GYP BOARD; ! Name !

  2. The devolution of mudbrick: ethnoarchaeology of abandoned earthen dwellings in the Bolivian Andes

    E-Print Network [OSTI]

    Kohler, Tim A.

    , mud plaster, and flooring. Adobes and mud plaster were locally derived from topsoil containing signature for decayed earthen houses. Rising damp exfoliated mud plaster despite un-mortared cobble wall

  3. Introducing a Clinical Practice Guideline Using Early CT in the Diagnosis of Scaphoid and Other Fractures

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    immobilization (mean time in plaster 2.7 days) and had no orwere immobilized in a plaster of Paris cast and referred todiagnosis, and duration of plaster and further treatment

  4. The social implications of ritual behavior in the Maya Lowlands : a perspective from Minanha, Belize

    E-Print Network [OSTI]

    Schwake, Sonja Andrea

    2008-01-01T23:59:59.000Z

    plaza floor (AP-1 st ). The plaster cap was completelybuilding. The poorly preserved plaster cap was approximatelyThe level consisted of a plaster cap and ballast layer for

  5. Multiplying the Variations

    E-Print Network [OSTI]

    Hill, Robin

    2011-01-01T23:59:59.000Z

    floor, 4,000 small blue plaster forms cast from paper cups.s description suggests, the plaster forms were arranged toon wax paper, cast plaster, pigment dimensions variable Page

  6. Energetic excess : the visual structure of movement in early Italian futurism, 1910-1915

    E-Print Network [OSTI]

    Mather, David S.

    2011-01-01T23:59:59.000Z

    C.R. no. 864 Dynamism, 1913, plaster (destroyed). Fig. 93.Forms of a Bottle, 1913, plaster (destroyed). Fig. 168.man in the crowd. Fig. 83. Plaster casts from archaeological

  7. Case Discussions

    E-Print Network [OSTI]

    Hill, Robin

    2011-01-01T23:59:59.000Z

    form of thousands of blue plaster cup shapes on the floorranged from cotton to wood, plaster and wax, string, scotchnew series, and include blue plaster castings of Dixie cups,

  8. Production of ritual material culture in the Pre-Pottery Neolithic period in Jordan : some methods for analytical investigation

    E-Print Network [OSTI]

    Bennallack, Kathleen Celia

    2012-01-01T23:59:59.000Z

    Near East: Experimental lime-plaster production at the Pre-just like bone, charcoal, plaster, and anything else thatsuch as studies of lime plaster (Goren and Goring-Morris

  9. Wooden Statuary

    E-Print Network [OSTI]

    Harvey, Julia

    2009-01-01T23:59:59.000Z

    a layer of paint or painted plaster on which the details ofdue to the fact that the plaster layer with the subtleduplicated not only on the plaster coating but also in the

  10. Amarna Art

    E-Print Network [OSTI]

    Laboury, Dimitri

    2011-01-01T23:59:59.000Z

    bust and 3D-rendering of plaster model head of Akhenaten (bust and 3D- rendering of plaster model head of Akhenaten (in the context of the plaster finds in Thutmoses workshop

  11. A survey of mushroom corals and the effects of water flow on sediment removal in Fungia species

    E-Print Network [OSTI]

    Ginsberg, Benjamin

    2008-01-01T23:59:59.000Z

    ingramsperhour,ofplasterofpariscubesplacednearmoving past fungiids, plaster of paris cubes wereon data from the plaster of paris cubes. All

  12. Intensities for the Four Largest Shocks of the New Madrid Earthquake Sequence

    E-Print Network [OSTI]

    Agnew, Duncan C

    2011-01-01T23:59:59.000Z

    or are heard to rustle. Weak plaster and masonry D cracked.at roof line. Fall of plaster, loose bricks, stones, tiles,limbs or fruit; cracking of plaster/stucco; some damage to

  13. Towards Multi-movement Hand Prostheses: Combining Adaptive

    E-Print Network [OSTI]

    Hellebrand, Sybille

    Create a plaster copy of the stump Make a 3D model of the plaster copy Create carrier foil from 2D muscular activity areas on foil Create another, slimmer plaster model Modulate muscular activity areas

  14. Reuse and Restoration

    E-Print Network [OSTI]

    Brand, Peter

    2010-01-01T23:59:59.000Z

    by Akhenaten. Some of the plaster used to mask the hack-Amarna hack-marks, and plaster. Photograph by the author.decoration in places where plaster used to mask the old

  15. Karnak: the Temple of Amun-Ra-Who-Hears-Prayers

    E-Print Network [OSTI]

    Gallet, Laetitia

    2013-01-01T23:59:59.000Z

    have been necessary to plaster them to a larger thickness ifin a generous layer of plaster, and the ribs and cupulesthe adhesion of the plaster (fig. 6). Figure 6. Peristyle

  16. INFLUENCE OF CURRENT SPEED, SUBSTRATE, AND PLANKTON ON THE DISTRIBUTION OF SUSPENSION FEEDERS IN MOOREA, FRENCH POLYNESIA

    E-Print Network [OSTI]

    Hann, Courtney Helen

    2012-01-01T23:59:59.000Z

    andondifferentdays. PlasterofParis(clodcards)werevelocity, measuredwithplasterofParisclodcards,didchangeinweightoftheplasterofParis clodcardswas

  17. Usurpation of Monuments

    E-Print Network [OSTI]

    Brand, Peter

    2010-01-01T23:59:59.000Z

    to decipher the initial text. Plaster used anciently to maskhave been suppressed with plaster before the final one wasRamesses VI re-inscribed it. Plaster used to mask one of the

  18. JOURNAL DE PHYSIQUE Colloque C1, supplkment au n02, Tome 47, f6vrier 1986 page cl-73

    E-Print Network [OSTI]

    Boyer, Edmond

    ,but a lack of knowledge exists on the contrclling microstructure parameters during casting on plaster mould of removal of water from the slip by the mould.The ,pparatus consists in a plaster mould (plaster/water ratio

  19. The Provincial Cemeteries of Naga ed-Deir: A Comprehensive Study of Tomb Models Dating from the Late Old Kingdom to the Late Middle Kingdom

    E-Print Network [OSTI]

    Kroenke, Karin Roberta

    2010-01-01T23:59:59.000Z

    three fragments of painted mud plaster near the entrance offound remnants of white plaster applied over mud and paintedof a figure painted on plaster survived on the back wall of

  20. The Dhiban Excavation and Development Project's 2005 Season

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    ed by a bn and a plaster and cobble surface, immediatelyoverlays a thick, well made plaster floor (Locus 12). Thissub-floor from an earlier plaster floor (Locus 18), which in

  1. Long-Term Stability of Personality: Implications for Behavior

    E-Print Network [OSTI]

    Nave, Christopher Scott

    2011-01-01T23:59:59.000Z

    R.R. (1994). Set like plaster: Evidence for the stability ofand middle adulthood: Set like plaster or persistent change?personality was ?set like plaster? by age 30 (Costa &McCrae,

  2. TECHNICAL SPECIFICATIONS LEON M. GOLDSTEIN PERFORMING ARTS CENTER

    E-Print Network [OSTI]

    Rosen, Jay

    Opening: 50' x 30' Grid Height: 90' Plaster Line to upstage wall: 50' Plaster Line to edge of apron: Pit teaser) Length of battens: 60' House Curtain color: Blue, guillotine CYC: W hite CYC from plaster line 36

  3. War, Peace, and Everything: Thoughts on Tolstoy

    E-Print Network [OSTI]

    Gaddis, John L

    2011-01-01T23:59:59.000Z

    behavior, he writes at one point, are like plasters assignedto plaster one side of a church wall, who, taking advantagea fit of zeal smear their plaster all over the windows, the

  4. The skull of Postosuchus kirkpatricki (Archosauria: Paracrocodyliformes) from the Upper Triassic of the United States

    E-Print Network [OSTI]

    Weinbaum, Jonathan C.

    2011-01-01T23:59:59.000Z

    9000) were obscured by plaster, wire mesh, and paint duringskull were covered by the plaster and paint used in theHoltz 1994). When plaster was removed from the upper

  5. Terra Terror: An Interdisciplinary Study of Earthquakes in Ancient Near Eastern Texts and the Hebrew Bible

    E-Print Network [OSTI]

    Roberts, Ryan Nathaniel

    2012-01-01T23:59:59.000Z

    brushwood roof, coated in plaster began to collapse into the14 tons of mortar and plaster, 14 tons for the ceiling andimpermeable rock needed no plaster while those with cracked

  6. NUDIBRANCH NEIGHBORHOOD: THE DISTRIBUTION OF TWO NUDIBRANCH SPECIES (CHROMODORIS LOCHI AND CHROMODORIS SP.) IN COOKS BAY, MOOREA, FRENCH POLYNESIA

    E-Print Network [OSTI]

    Hubner, Gwen

    2011-01-01T23:59:59.000Z

    LT and Glenn EP. 1994. Plaster standards to measure watermeasure current, I used plaster of Paris (calcium sulfate).standard ice cube tray, plaster of Paris cubes measure water

  7. SmartCast - Novel Textile Sensors for Embedded Pressure Sensing of Orthopedic Casts

    E-Print Network [OSTI]

    Danilovic, Andrew

    2013-01-01T23:59:59.000Z

    J. Kaiser, Chair An orthopedic plaster or fiberglass cast is1 - Introduction 1.1 Background A plaster or fiberglass castunderstand how well a plaster or fiberglass cast fits over

  8. Emancipatory Digital Archaeology

    E-Print Network [OSTI]

    Morgan, Colleen

    2012-01-01T23:59:59.000Z

    and you can see a crumbled plaster wall rising around her.make-up context to a white plaster 10 floor and must beexcavated and to dig the white plaster floor would be out of

  9. Portrait versus Ideal Image

    E-Print Network [OSTI]

    Laboury, Dimitri

    2010-01-01T23:59:59.000Z

    649. ) Figure 13. Table with plaster studies and busts (at2010 Figure 13. Table with plaster studies and busts (at thewas unearthed there among plaster studies of heads and faces

  10. Molecular gating dynamics of the cytoplasmic domains of inwardly rectifying potassium (Kir) channels

    E-Print Network [OSTI]

    Pegan, Scott Dusan

    2006-01-01T23:59:59.000Z

    Neurosci 20, 156-162. Plaster, N. M. , Tawil, R. , Tristani-channels. Neuron 37, 953-962. Plaster, N. M. , Tawil, R. ,H. , Fidzianska, A. , Plaster, N. , et al. (2002).

  11. Nomads in transition : mortuary archaeology in the lowlands of Edom (Jordan)

    E-Print Network [OSTI]

    Beherec, Marc A.

    2011-01-01T23:59:59.000Z

    4.13: Thick layer of mud plaster over the capstones of Gravesmaller cobbles and some mud plaster, but not all the gapswith a layer of hard mud plaster. Because of this seal, the

  12. NOTICE TO BUILDING OCCUPANTS ASBESTOS-CONTAINING MATERIALS

    E-Print Network [OSTI]

    Holland, Jeffrey

    system insulation, cement board, floor tile, ceiling tile, and acoustic plaster. Asbestos can be a health, drill, or pulverize asbestos-containing floor tile, linoleum, acoustic plaster, spray

  13. Energy saving and improved comfort by increased air movement

    E-Print Network [OSTI]

    Schiavon, Stefano; Melikov, Arsen

    2008-01-01T23:59:59.000Z

    constructed with 20 mm of plaster, 100 mm of glasswool, 240and 10 mm of internal plaster. The window has an external

  14. INSTRUCTIONS FOR OPERATING LBL PASSIVE ENVIRONMENTAL RADON NOMITOR (PERM)

    E-Print Network [OSTI]

    Boegel, M.L.

    2010-01-01T23:59:59.000Z

    M A T E R I A L S V'.lls: plasterboard, wood, plaster, .carpet, plaster, brick, other (specify) other (specify)

  15. E-Print Network 3.0 - assisted rapid palatal Sample Search Results

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

    Databases and Resources ; Biology and Medicine 86 Automatic 3D modeling of palatal plaster casts Marco Andreetto Summary: Automatic 3D modeling of palatal plaster casts Marco...

  16. R! U.S. DEPARTMENT OF ENERGY EERE PROJECT MANAGEMENT CENTER

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

    building though trace elements of asbestos are contained in the plaster. The asbestos abatement was performed according to the recipient's waste management plan . The plaster...

  17. Gypsum scale formation on a heated copper plate under natural convection conditions and produced water remediation technologies review .

    E-Print Network [OSTI]

    Mirhi, Mohamad H. (Mohamad Hussein)

    2013-01-01T23:59:59.000Z

    ??Scaling or crystallization fouling of unwanted salts is one of the most challenging and expensive problems encountered in different applications such as heat exchangers and (more)

  18. Endolithic cyanobacteria in soil gypsum: Occurrences in Atacama (Chile), Mojave (United States), and Al-Jafr Basin (Jordan) Deserts

    E-Print Network [OSTI]

    Ahmad, Sajjad

    ), and Al-Jafr Basin (Jordan) Deserts Hailiang Dong,1 Jason A. Rech,1 Hongchen Jiang,1 Henry Sun,2, United States, and Al-Jafr Basin, Jordan, revealed endolithic cyanobacteria communities just below (United States), and Al-Jafr Basin (Jordan) Deserts, J. Geophys. Res., 112, G02030, doi:10.1029/2006JG

  19. 3D geological modelling at urban scale and mapping of ground movement susceptibility from gypsum dissolution: the Paris example (France)

    E-Print Network [OSTI]

    Boyer, Edmond

    , the Inspection Générale des Carrières (IGC; General Inspectorate of Quarries) has the task of managing the risks

  20. Gypsum scale formation on a heated copper plate under natural convection conditions and produced water remediation technologies review

    E-Print Network [OSTI]

    Mirhi, Mohamad H. (Mohamad Hussein)

    2013-01-01T23:59:59.000Z

    Scaling or crystallization fouling of unwanted salts is one of the most challenging and expensive problems encountered in different applications such as heat exchangers and thermal water treatment technologies. Formation ...

  1. CaveSculpture: Creating sculpture from CavePaintings

    E-Print Network [OSTI]

    Laidlaw, David

    of plaster in an additive process. Consecutive layers of plaster are "printed" with colored binder. As the layers accumulate, the model is built. Once the model is created, excess plaster is removed to withstand handling. Due to the fragility of plaster, mode

  2. Kursplan fr Form, frg och produktuttryck

    E-Print Network [OSTI]

    and presenting design ideas.q Little Brown. 1985. Shimizu Yoshiharu. Models & Prototypes, Clay, Plaster

  3. Institut fr Massivbau und Baustofftechnologie Abteilung Massivbau Shaking Table test of a pre-damaged

    E-Print Network [OSTI]

    .-Ing Moritz Urban #12;Reinforcement Systems System 1: eq-top textile application on plaster no removal of plaster special ductile adhesive clean solution IMB Karlsruhe ­ Massivbau3 09.02.2012 Dipl.-Ing Moritz Urban textile application on plaster no removal of plaster special ductile adhesive clean solution #12

  4. Kursplan fr lsret 2010/2011 (Genererad 2010-06-28.)

    E-Print Network [OSTI]

    design ideas. Little Brown. 1985 Shimizu Yoshiharu. Models & Prototypes, Clay, Plaster, Styrofoam, Paper

  5. Fall Semester 2013 Courses, Independent Studio

    E-Print Network [OSTI]

    soft and hard slabs, use of slump molds, coil building and plaster mold making. Porcelain Instructor

  6. Richard P. Vlosky1 , Todd Shupe, Qinglin Wu

    E-Print Network [OSTI]

    (cartons) in living trees and wooden buildings, and even penetrate plaster, plastic, asphalt, mortar

  7. Kursplan fr lsret 2011/2012 (Genererad 2011-08-31.)

    E-Print Network [OSTI]

    design ideas. Little Brown. 1985 Shimizu Yoshiharu. Models & Prototypes, Clay, Plaster, Styrofoam, Paper

  8. Product development of FGD recovered magnesium hydroxide

    SciTech Connect (OSTI)

    Beeghly, J.H.; Babu, M.; Smith, K.J.

    1999-07-01T23:59:59.000Z

    The ThioClear FGD processes developed by the Dravo Lime Company (DLC) produce a high brightness gypsum and magnesium hydroxide (Mg(OH){sub 2}) by-product. Both originate as white precipitates from a solution of magnesium sulfate. The use of magnesium-enhanced lime avoids the mineral impurities from direct neutralization when using pulverized limestone rock. White, pure FGD synthetic gypsum can be used to produce higher value products such as mineral fillers and industrial plasters. This paper focuses on the product development of the Mg(OH){sub 2} by-product. Commercial Mg(OH){sub 2} sells at over $200/Ton for a variety of uses, most of which is wastewater treatment and a feedstock to make magnesium chemicals and refractories. Beneficial uses in the power plant are pH control of acidic coal pile stormwater runoff and bottom ash quench water. A future use being explored is injection into coal fired boilers to neutralize sulfur trioxide (SO{sub 3}) to prevent stack gas opacity related emission problems and minimize air preheater corrosion and fouling. The objective of this project is to improve the purity and solids content of the by-product after it is separated from the gypsum. Several options were investigated to convert it into a more marketable or usable form. Test results and economic evaluations are reported during the different process steps needed to improve the product quality: (1) dissolving or washing out the gypsum impurity; (2) thickening the washed solids and using the overflow for makeup water within the FGD water balance; (3) finding the best means to dewater the washed, thickened slurry; and (4) repulp the dewatered cake into a stabilized slurry or dry it to powder. Flash drying the dewatered cake is compared to spray drying the thickened slurry. FGD Mg(OH){sub 2} is shown to have equal reactivity as an acid neutralization reagent on a Mg(OH){sub 2} molar basis to commercial Mg(OH){sub 2} products and other alkaline reagents. Its use for pH control in wastewater treatment is shown to produce a much smaller sludge volume than lime or sodium hydroxide.

  9. Thermal performance of phase change wallboard for residential cooling application

    SciTech Connect (OSTI)

    Feustel, H.E.; Stetiu, C.

    1997-04-01T23:59:59.000Z

    Cooling of residential California buildings contributes significantly to electrical consumption and peak power demand mainly due to very poor load factors in milder climates. Thermal mass can be utilized to reduce the peak-power demand, downsize the cooling systems, and/or switch to low-energy cooling sources. Large thermal storage devices have been used in the past to overcome the shortcomings of alternative cooling sources, or to avoid high demand charges. The manufacturing of phase change material (PCM) implemented in gypsum board, plaster or other wall-covering material, would permit the thermal storage to become part of the building structure. PCMs have two important advantages as storage media: they can offer an order-of-magnitude increase in thermal storage capacity, and their discharge is almost isothermal. This allows the storage of high amounts of energy without significantly changing the temperature of the room envelope. As heat storage takes place inside the building, where the loads occur, rather than externally, additional transport energy is not required. RADCOOL, a thermal building simulation program based on the finite difference approach, was used to numerically evaluate the latent storage performance of treated wallboard. Extended storage capacity obtained by using double PCM-wallboard is able to keep the room temperatures close to the upper comfort limits without using mechanical cooling. Simulation results for a living room with high internal loads and weather data for Sunnyvale, California, show significant reduction of room air temperature when heat can be stored in PCM-treated wallboards.

  10. Visualizing Mathematics -Online -Konrad Polthier

    E-Print Network [OSTI]

    Polthier, Konrad

    , and therefore the large size of the collection of more than 500 plaster models is even more impressing photos of many models is given in Fischer's book [3]. Fig. 2. Left image: Plaster model by Martin

  11. Time-Varying BRDFs Bo Sun, Student Member, IEEE Computer Society, Kalyan Sunkavalli,

    E-Print Network [OSTI]

    Yang, Junfeng

    , spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of paints (watercolor, spray, and oil), drying of wet rough surfaces (fabrics, plaster, and cement

  12. Mesh Resolution Augmentation using 3D Skin Bank Won-Sook Lee*

    E-Print Network [OSTI]

    Lee, WonSook

    on a 100-micron resolution scan of plaster cast molds of the actors' faces. Human skin was modeled using, as shown in Figure 1. Each individual is presented with closed eyes and mouth due to the use of plaster

  13. An Ultra-Wideband Radar System for Through-the-Wall Imaging using a Mobile Robot

    E-Print Network [OSTI]

    through denser sheetrock, plaster, and brick requires operation below 10 GHz; this band however yields, plaster, brick, and concrete blocks requires operation below 10 GHz [2], [3]; this band however yields

  14. Jeff Martin (U. Winnipeg) Collaborators: J.D. Bowman, J. Birchall, L. Buchmann, L. Clarke, C. Davis, B.W. Filippone,

    E-Print Network [OSTI]

    Martin, Jeff

    , B. Plaster, I. Tanihata, W.T.H. van Oers, Y. Watanabe, S. Yamashita, T. Yoshioka (Winnipeg, Manitoba.D. Bowman, B. Filippone, T. Ito, B. Plaster #12;UCN Quantum States in Gravity Quantized energy leve

  15. 2000. The Journal of Arachnology 28:243244 RESEARCH NOTE

    E-Print Network [OSTI]

    Carrel, James E.

    of a transparent bottle, embedding the rods in a 2 cm thick layer of patching plaster poured into the bot- tom section, and taping the capped top section back on the bottom section after the plaster was dry. Once

  16. 3D Statistical Models for Tooth Surface Reconstruction

    E-Print Network [OSTI]

    Boyer, Edmond

    , orthodontists regularly employ plaster casts of the patient's dentition, also known as study models. These plaster models are used to prepare treatment plans and for making accurate measurements. However

  17. THE CIRCULATORY SYSTEM AND BLOOD General charectertllUCIL______ _ _______ 23ll

    E-Print Network [OSTI]

    by the following method. A solution of plastic or a thin mixture of plaster of paris is poured into the pericardium from which the heart has been re- moved; after the material has l!8t, the plaster molds

  18. SD001-15 SD001-DeChadarevian SD001-DeChadarevian-v4.cls February 16, 2004 20:41 Commentaries

    E-Print Network [OSTI]

    The essays in this book on three-dimensional models in wax, wood, wire, plaster, and plastic challenge, yet switching formal tools was only one step; wood, wire, plaster, and wax remain to be accommodated

  19. Texture analysis and perception Michael S. Landy

    E-Print Network [OSTI]

    Landy, Michael S.

    reflectance (wood grain), resulting from the interplay of illumination and a variegated 3-d surface (plaster small bumps in a plaster wall, single growth lines in wood) that repeat, possibly with variation, across

  20. ARTHRITIS & RHEUMATISM Vol. 62, No. 10, October 2010, pp 30593063

    E-Print Network [OSTI]

    Bradman,4 and Christopher A. Plaster4 Objective. To assess whether there is a statisti- cally significant, Christopher A. Plaster, MSc: University College London, London, UK. Dr. Bradman is a trustee of the Melford

  1. SOUTHEASTERN NATURALIST2004 3(4):653658 Recent Record of a Cougar (Puma concolor) in Louisiana,

    E-Print Network [OSTI]

    , carcass, live capture, scat, or plaster cast of a track, appears to exist only for some portions and a plaster cast made of a track found in north- eastern Louisiana in 1975 (Yenke 1982). We are unaware

  2. 3D head anthropometric analysis Reyes Enciso*ab

    E-Print Network [OSTI]

    Shahabi, Cyrus

    a current three-dimensional image-based face modeling technique using a plaster head model. We will also. In this paper we acquired and validated 3-dimensional images of a plaster head using structured-light image

  3. Computers in Biology and Medicine 37 (2007) 14611471 www.intl.elsevierhealth.com/journals/cobm

    E-Print Network [OSTI]

    Payan, Yohan

    working with CT data, orthodontists regularly employ plaster casts of the patient's den- tition, also known as study models. These plaster models are used to prepare treatment plans and for making accurate

  4. N, &is.ngse aReleased upon receipt but intended f o r w e

    E-Print Network [OSTI]

    embedded just above the aurfaco of the There is a central boiler plant, Plaster coilings. heating season

  5. Kursplan fr lsret 2008/2009 (Genererad 2008-07-17.)

    E-Print Network [OSTI]

    Teckna. Strömbergs bokförlag. 1994 Shimizu Yoshiharu. Models & Prototypes, Clay, Plaster, Styrofoam

  6. E-Print Network 3.0 - anterior segmental osteotomy Sample Search...

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

    skeletal analysis for morphological diagnostic and osteotomy simulation (called... plaster casts Type of osteotomy (maxillar andor mandibular) Quantitative displacement...

  7. A Science Service _F?-ature----e.--. Bel.erzsed upon receipt

    E-Print Network [OSTI]

    appeared i n brick walls, foundations, plaster, cement walks, etc. As oarly as last July h i s office row

  8. Kursplan fr lsret 2009/2010 (Genererad 2009-08-11.)

    E-Print Network [OSTI]

    Teckna. Strömbergs bokförlag. 1994 Shimizu Yoshiharu. Models & Prototypes, Clay, Plaster, Styrofoam

  9. Kursplan fr lsret 2007/2008 FORM OCH FRG MMK080

    E-Print Network [OSTI]

    Teckna. Strömbergs bokförlag. 1994 Shimizu Yoshiharu. Models & Prototypes, Clay, Plaster, Styrofoam

  10. Bravo Araby Navy Base Holtville

    E-Print Network [OSTI]

    Plaster City No Man's Land Imperial Valley East Mesa No. 3 East Mesa No. 2 East Mesa No. 1 Dixieland

  11. Conceptual Design Report Neutron Electric Dipole Moment Project

    E-Print Network [OSTI]

    at Berkeley, Berkeley, CA 94720, USA R. Carr, B. Filippone, R. McKeown, B. Plaster, R. Schmid California

  12. Purpose: The purpose of this lab is to describe fossils and to demonstrate how they are made. Paper bowls or cups

    E-Print Network [OSTI]

    Benitez-Nelson, Claudia

    they are made. Materials Paper bowls or cups Modeling clay Plaster of paris Water Bowl or bucket they have their "molds" made, mix the plaster of paris according to package directions and fill the molds with the mixture. The plaster will have to at least dry overnight. Then, they can remove the paper container

  13. Pull-Push Level Sets: A new term to encode prior knowledge for the segmentation of teeth images

    E-Print Network [OSTI]

    segmentation from 2D images of dental plaster cast models is a difficult problem because it is necessary is a desirable goal.2 In principle, this could be done by studing a 2-D image of a dental plaster cast model of a plaster cast of a dental arch. dealing with merging of different contours into a single one (which

  14. 17 me Congrs Franais de Mcanique Troyes, septembre 2005 Modle thermomcanique et rupture pour les plaques multicouches

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of cardboard-plaster-cardboard (CPC). The develo- ped model is adapted to a range of temperature for which the cardboard and the plaster can be destroyed. This model is also developed for a level of stress corresponding to the rupture of the cardboard and the plaster. The mathematical-mechanical model and numerical simulations

  15. Damage law identification from full field displacement measurement: Application to four-point bending test for

    E-Print Network [OSTI]

    the behavior of plaster- board through a homogenized continuum description where the progressive degradation. Introduction The use of plaster as a building material has a very long and rich his- tory. In their quest- lationship between microstructure and mechanical properties of raw plaster or core of the board (Murat et al

  16. Meissner's Mysterious Bodies Bernd Kawohl & Christof Weber

    E-Print Network [OSTI]

    Kawohl, Bernd

    by plaster. Figure 1 appears to be the earliest drawing showing a nontrivial three-dimensional body of "the" Meissner body. The earliest printed photograph of a plaster Meissner body, the one de- scribed") in the Palais de la D´ecouverte in Paris (see #12;3 Figure 2: Plaster Model of Meissner body MV Figure 8

  17. 3D Reconstruction of the Human Jaw from A Sequence of Images

    E-Print Network [OSTI]

    Farag, Aly A.

    repeated acquisition of radiographs may result in undesired side effects. Obtaining a plaster model the analysis of X-rays and plaster models. In [l], a computer-vision technique was de- veloped for the acquisition and processing of 3D pro- files of dental imprints which still requires a plaster mode1

  18. About the Work of Art A chain of children dance and play around the

    E-Print Network [OSTI]

    Mayfield, John

    the fountain was not cast in bronze at the time of its creation. The plaster fountain remained located the plaster fountain from Petersen's daughter, Mary. In 1999, the decision was made to cast the original plaster fountain in bronze for the new Palmer Human Development and Family Studies (HDFS) Building

  19. Optimization of 3D Shape Sharpening Filter Based on Geometric Statistical Values

    E-Print Network [OSTI]

    Tokyo, University of

    City University Hiroshima, JAPAN http://ime.info.hiroshima-cu.ac.jp/ Abstract A plaster statue is an object created from a mold made from a stone statue, for example, and into which plaster is poured in that the plaster statue has a smoother shape than does the original statue. Consequently in this re- search

  20. Digital volume correlation applied to X-ray tomography images from spherical indentation tests on lightweight

    E-Print Network [OSTI]

    . Keywords: Digital volume correlation; global approach; reduced basis; strain eld; plaster 1 Introduction in the board slurry is to create voids 1 #12;to further reduce the nal weight of the board at xed plaster/water ratio. To improve the adhesion between paper and plaster, starch is added in most cases

  1. EG-Models -A New Journal for Digital Geometry Models

    E-Print Network [OSTI]

    Polthier, Konrad

    to build up large col- lections of plaster models in the 19th century for educational purposes and the plaster collections with mod- ern computer tools. But the possibilities of the digital models go well beyond those of the libraries with classical plaster shapes and dynamic steel models in earlier days

  2. Remembrance of an absence Report by Cati Vaucelle

    E-Print Network [OSTI]

    Ishii, Hiroshi

    & the plaster sculpted with chisel, and the angelic face of the doll made of white wax. This sculpture is a tool an outside of the dysmorphic body. I used video to revisit a plaster mold carved for this mixed media of a souvenir and its effect over time. Ideally I planned on printing on plaster molds a series of clothing

  3. JOURNALDE PHYSIQUE IV Colloque C7,supplbment au Journal de Physique 111, Volume 3, novembre 1993

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    O has been introduced in the form of either plaster of Paris (to reproduce a possible contamination employed for preparing layered materials by slip casting in plaster of Paris molds. Details the effect of CaO introduced during the slip casting process in the alumina compacts from the plaster moulds

  4. Probabilistic uncertainty modeling for thermo-mechanical analysis of plasterboard submitted to re load

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    with a probabilistic modeling of the thermo-mechanical behavior of cardboard-plaster-cardboard (CPC) multilayer plates resistance, cardboard-plaster-cardboard multilayer, un- certainties, probabilistic model, experiments presented in the last section. A plasterboard (cardboard-plaster-cardboard (CPC) multiplayer) gives

  5. Journal of StructuraIGeology, Vol. 18, No. 5, pp. 673 to 681.1996 Copyright 0 1996 Elsevier Science Ltd

    E-Print Network [OSTI]

    Fossen, Haakon

    -8141(95)00105-0 Experimental modeling of extensional fault systems by use of plaster HAAKON FOSSEN Statoil, N-5020 Bergen experiments with plaster as the deforming medium produce faults and related structures that closely resemble soft plaster as the modeling material. Because of its very fine grain size, its fast transition from

  6. Correlation Model for 3D Texture Kristin J. Dana and Shree K. Nayar

    E-Print Network [OSTI]

    Nayar, Shree K.

    angle v is 33.75 , 56.25 and 78.75 . These images were obtained from a rough plaster sample. These views were generated by warping the frontal view of the same plaster surface. This contrived 2D texture has the same appearance in the frontal view as the rough plaster sample. fects that depend

  7. The Science of Sentiment

    E-Print Network [OSTI]

    Bates, Jamie M.

    2012-05-31T23:59:59.000Z

    the models were completed I then took plaster molds of the heads and prepared the molds to be filled with glaze. I filled the molds with a glaze and silica sand... the kiln with the plaster mold included. When the pieces were removed from the kiln the chemical water was no longer present in the plaster and the mold crumbled...

  8. Color Rapid Prototyping for Diffusion-Tensor MRI Visualization

    E-Print Network [OSTI]

    Laidlaw, David

    . Laidlaw, Christopher W. Bull Brown University, Providence, RI 02912, USA a) b) c) Fig. 1. (a,b) A plaster color rapid prototyping (RP) plaster mod- els as visualization tools to support scientific research by the printer software. These layers are then manufactured by putting down a thin layer of plaster powder

  9. PALEONTOLOGICAL REPORT RAPPORT DE PALONTOLOGIE

    E-Print Network [OSTI]

    Hagadorn, Whitey

    PALEONTOLOGICAL REPORT RAPPORT DE PAL?ONTOLOGIE REPORT 001-RBM-2006 REPORT ON PLASTER CASTS;Report 001-RBM-2006/1 Report on plaster casts of arthropod-produced trace fossils (Protichnites) figured, two plaster casts of each specimen have been produced and all material has been catalogued in the GSC

  10. Inside this issue Thomas Barlow's books at Queen's

    E-Print Network [OSTI]

    Capdeboscq, Yves

    presentation copy in Queen's College Library? Mark Rankin The plaster ceiling and its Masters at The Queen the specialist conservators working on the stonework, plaster and timber, to contribute to what I expect's issue an article by my former colleague Veronika Vernier on the plaster ceiling in the Upper Library

  11. A METHOD OF PREPARING FISHES FOR MUSEUM AND EXHIBITION PURPOSES

    E-Print Network [OSTI]

    , by alcoholics, mounted skins, and plaster casts. The following are some of the commonly accepted objections of the fish, not a part of it. (3) Plaster casts may reproduce the . form perfectly, but all t ranslucency with clay. Now pour plaster over the fish and allow it to harden thoroughly, after which the fish may

  12. Simulated energy savings of cool roofs applied to industrial premises in the Mediterranean Area

    E-Print Network [OSTI]

    De Carli, Michele; Scarpa, Massimiliano; Schiavon, Stefano; Zecchin, Roberto

    2007-01-01T23:59:59.000Z

    are constructed with 20 mm of plaster, 70 mm of glasswooland 10 mm of internal plaster. The windows have a U-values r = 0.83 High Internal (Plaster) t = 0.06 m t = 0.20 m Low

  13. Shape Recovery of the Jaw Impression from A Sequence of Images M. Ahmed, S. Yamany, E. Hwnayed. and .% Farag

    E-Print Network [OSTI]

    Louisville, University of

    effects. Obtaining a plaster model of the jaws is a complex operation for the orthodontist, and is wry to the expert system are still acquired manually from the analysis of X-rays and plaster models. In [1 imprints which still requires a. plaster model as an input to their system. The system: shown in figure 1

  14. file:///S|/ASBESTOS/NISTIRs/FRJan1994ClarificationMultilayers.txt[1/20/2011 11:19:53 AM] [Federal Register: January 5, 1994

    E-Print Network [OSTI]

    and the results reported by layer (discrete stratum). Specific examples are given below. Plaster/Stucco Systems If plaster and stucco wall or ceiling systems are layered, and the layers can be distinguished, then the layers must be analyzed separately. Where a plaster or stucco wall system is constructed in layers

  15. Precision of Surface Measurements for Below-Knee Residua Paul K. Commean, BEE, Kirk E. Smith, AAS, James M. Cheverud, PhD, Michael W. Vannier, MD

    E-Print Network [OSTI]

    Cheverud, James M.

    ) residua and their BK plaster positive casts using calipers, electromag- netic digitizer, optical surface digitizer; residuum was scanned using three- dimensional(3D) OSS; a negative plaster cast of subject's resid measurement session. Plaster positive casts were constructed and subsequently mea- sured using the same

  16. UNIVERSITY OF HAWNI LIBRARY MASS TRANSFER LIMITS TO NUTRIENT UPTAKE BY SHALLOW CORAL

    E-Print Network [OSTI]

    Luther, Douglas S.

    compared the dissolution of artificial plaster forms (surface area = 0.1-1.0 m2 ) of varying roughness) than under steady flows. Using appropriate surface areas from the plaster dissolution experiments enhancement obtained from the plaster dissolution experiments, S could be as high as 9.3±1.3 m day·1 and 15

  17. Corrosion-induced degradation of GaAs PHEMTs under operation in high humidity conditions

    E-Print Network [OSTI]

    Hisaka, Takayuki

    We have comprehensively investigated the degradation mechanism of AlGaAs/InGaAs pseudomorphic high-electron-mobility transistors (PHEMTs) under operation in high humidity conditions. PHEMTs degradation under high humidity ...

  18. Modifications du travail de sortie des surfaces clives de GaAs, lies au refroidissement

    E-Print Network [OSTI]

    Boyer, Edmond

    les positions energetiques des etats de surface. Cette idee a ete reprise et developpee par L. K experimentaux ne posent pas de probleme majeur [6], 1'exp6rimentation, delicate, conduit a se poser la question

  19. Fourier spectroscopy of individual nitrogen impurity centers in GaAs

    SciTech Connect (OSTI)

    Ikezawa, Michio [PRESTO-JST, JST, Kawaguchi, Japan and Institute of Physics, University of Tsukuba, Tsukuba (Japan); Zhang, Liao; Mori, Tatsuya; Masumoto, Yasuaki [Institute of Physics, University of Tsukuba, Tsukuba (Japan); Sakuma, Yoshiki; Sakoda, Kazuaki [National Institute for Materials Science, Tsukuba (Japan)

    2013-12-04T23:59:59.000Z

    We report on the measurement of the exciton homogeneous linewidth in nitrogen impurity centers in GaAs:N. Fourier spectroscopy on a single center revealed a long coherence time over 300 ps at low temperature. The narrowest linewidth obtained at liquid helium temperature is 3.5 ?eV, which is comparable with that of semiconductor quantum dots. The linewidth increases with increasing temperature, showing a thermally activated behavior with activation energies of 2?5 meV.

  20. E-Print Network 3.0 - activated si-gaas high-voltage Sample Search...

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

    Polytechnique, Centre de mathmatiques Collection: Mathematics 48 1 of 5 Copyright 2007 Tesla Motors Updated: December 19, 2007 The Tesla Roadster Battery System Summary: to...

  1. The design of GaAs HEMT and HBT Bessel-type transimpedance amplifiers

    E-Print Network [OSTI]

    Adeyemi, Oluwafemi Ibukunoluwa

    2007-04-25T23:59:59.000Z

    for Noise Analysis of Open-Loop Common-Gate TIA... 25 Fig. 3.6. Feedback TIA.. 26 Fig. 3.7. Feedback TIA Characteristics. 28 Fig. 3.8. HEMT and HBT Feedback TIAs 30 Fig. 3.9. Photodiode.../ driver Repeaters Optical Fiber Several miles Optical Fiber Laser Diode Photodiode Preamplifier/ Transimpedance Amplifier Automatic Gain Control Digital Information Digital Information Receiver Fig. 1.1. Illustration of a Digital Fiber...

  2. Weak localization of dilute 2D electrons in undoped GaAs heterostructures.

    SciTech Connect (OSTI)

    Seamons, John Andrew; Lilly, Michael Patrick; Reno, John Louis; Bielejec, Edward Salvador

    2004-07-01T23:59:59.000Z

    The temperature dependence of the resistivity and magnetoresistance of dilute 2D electrons are reported. The temperature dependence of the resistivity can be qualitatively described through phonon and ionized impurity scattering. While the temperature dependence indicates no ln(T) increase in the resistance, a sharp negative magnetoresistance feature is observed at small magnetic fields. This is shown to arise from weak localization. At very low density, we believe weak localization is still present, but cannot separate it from other effects that cause magnetoresistance in the semi-classical regime.

  3. E-Print Network 3.0 - adsorbate covered gaas1 Sample Search Results

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

    ; Physics ; Materials Science 82 Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky* Summary: that the...

  4. Excitation-Dependent Recombination and Diffusion Near an Isolated Dislocation in GaAs

    SciTech Connect (OSTI)

    Gfroerer, T. H.; Crowley, C. M.; Read, C. M.; Wanlass, M. W.

    2012-06-01T23:59:59.000Z

    In low-magnification, plan-view photoluminescence images of a nominally lattice-matched, undoped GaAs/GaInP heterostructure, we observe a random distribution of isolated dark spots. We attribute the dark spots to crystal dislocations, where nonradiative recombination is augmented by transitions utilizing defect-related energy levels between the conduction and valence bands. We note that, when the laser excitation intensity is reduced, the darkened regions expand. At lower excitation, the density of photogenerated electrons and holes is reduced, and they are more likely to reach the defective region before encountering a partner for radiative recombination. When we model the behavior with a simulation that allows for Laplacian diffusion and defect-related recombination only through mid-bandgap energy levels, we do not obtain good agreement between experimental and simulated images. But if we allow for an arbitrary distribution of defect levels, such that the occupation of the levels and bands can change independently, we have more flexibility for fitting the density-dependent recombination rates. The more sophisticated model produces results that are more consistent with experimental images.

  5. Recent improvements in materials for thin GaAs and multibandgap solar cells

    SciTech Connect (OSTI)

    Benner, J.P.

    1985-05-01T23:59:59.000Z

    The High Efficiency Concepts Program at SERI supports research on III-V compound semiconductors with the objective of achieving the maximum attainable photovoltaic conversion efficiencies for terrestrial solar electric power. The outcome of this research may also affect the future of space photovoltaic cells. While the interest in thin-film, high-efficiency solar cells for terrestrial applications is driven principally by consideration of system costs, such cells would also improve the power density of space power arrays.

  6. Copper Doped GaAs Infrared Filter for the 8-13 m Atmospheric Window

    E-Print Network [OSTI]

    Peale, Robert E.

    regions of interest, such as atmospheric transmission windows. Filters exclude solar or thermal photonsCdTe is typically melt grown in a high temperature furnace. All three elements in this alloy are toxic. Stability

  7. Double Power Output for GaAs Solar Cells Embedded in Luminescent Waveguides

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct:Directives Templates8. U.S.Donald R. Baer

  8. Surface Science Analysis of GaAs Photocathodes Following Sustained Electron

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline GalliumSuppression of conductivity inBatteriesonBeam Delivery. |

  9. GaAs on Si,,111...--crystal shape and strain relaxation in nanoscale patterned growth

    E-Print Network [OSTI]

    New Mexico, University of

    . R. Dawson, and S. R. J. Brueck Center for High Technology Materials and Department of Electrical and Computer Engineering, University of New Mexico, 1313 Goddard, SE, Albuquerque, New Mexico 87106 Y.-B. Jiang Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87103 Received

  10. Use of coconut fiber as a low-cost thermal insulator

    SciTech Connect (OSTI)

    Kochhar, G.S.; Manohar, K. [Univ. of the West Indies, St. Augustine (Trinidad and Tobago)

    1997-11-01T23:59:59.000Z

    Cost is one of the major factors to be considered when choosing a thermal insulator. Design engineers continuously strive to provide the best at the lowest possible cost. In the tropics climate conditions are essentially hot and humid and a cause for daily discomfort. To some extent, air-conditioning of buildings has solved this problem. The major deterrent to air-conditioning is the exorbitant cost of imported thermal insulation materials. This has prompted a search for local, low-cost but effective thermal insulation for buildings. Coconut fiber is available at minimal cost from the copra industry in Trinidad, as it is a waste product from the coconut. The viability of using coconut fiber as building thermal insulation was explored by conducting thermal conductivity tests on 200 mm X 400 mm X 60 mm thick slab-like specimens. The test equipment used was a locally designed constant temperature hot box apparatus. This apparatus was designed to test slab-like specimens under steady-state conditions. The reliability if this experimental set up was checked using Gypsum Plaster. The thermal conductivity test results for coconut fiber over the density range 30 kg/m{sup 3} to 115 kg/m{sup 3} showed the characteristic hooked shape graph for fibrous material. For the 60 mm thick specimens at a mean temperature of 39 C, a minimum thermal conductivity of 0.058 W/mK occurred at an optimum density of 85 kg/m{sup 3}. The thermal conductivity of commonly used industrial insulators, namely loose-fill expanded vermiculite, cellular glass and blanket fiber glass, at a mean temperature of 38 C are 0.066 W/mK, 0.061 W/mK and 0.052 W/mK respectively. When compared, these results show that air dried coconut fiber has far reaching potential for use as an effective building thermal insulation.

  11. Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor. Quarterly technical progress report, 1996

    SciTech Connect (OSTI)

    Zauderer, B.

    1996-11-01T23:59:59.000Z

    The objective of this 24 month project is to determine the degree of sulfur retention in slag in a full scale cyclone coal combustor with sulfur capture by calcium oxide sorbent injection into the combustor. This sulfur capture process consists of two steps: Capture of sulfur with calcined calcium oxide followed by impact of the reacted sulfur-calcium particles on the liquid slag lining the combustor. The sulfur bearing slag must be removed within several minutes from the combustor to prevent re-evolution of the sulfur from the slag. To accomplish this requires slag mass flow rates in the range of several 100 lb/hr. To study this two step process in the combustor, two groups of tests are being implemented. In the first group, calcium sulfate in the form of gypsum, or plaster of Paris, was injected in the combustor to determine sulfur evolution from slag. In the second group, the entire process is tested with limestone and/or calcium hydrate injected into the combustor. This entire effort consists of a series of up to 16 parametric tests in a 20 MMtu/hr slagging, air cooled, cyclone combustor. During the present quarterly reporting period ending September 30,1996, three tests in this project were implemented, bringing the total tests to 5. In addition, a total of 10 test days were completed during this quarter on the parallel project that utilizes the same 20 MMtu/hr combustor. The results of that project, especially those related to improved slagging performance, have a direct bearing on this project in assuring proper operation at the high slag flow rates that may be necessary to achieve high sulfur retention in slag.

  12. Simplified numerical description of latent storage characteristics for phase change wallboard

    SciTech Connect (OSTI)

    Feustel, H.E.

    1995-05-01T23:59:59.000Z

    Cooling of residential California buildings contributes significantly to electrical consumption and peak power demand. Thermal mass can be utilized to reduce the peak-power demand, down-size the cooling systems and/or switch to low-energy cooling sources. Large thermal storage devices have been used in the past to overcome the short-comings of alternative cooling sources or to avoid high demand charges. With the advent of phase change material (PCM) implemented in gypsum board, plaster or other wall-covering material, thermal storage can be part of the building structure even for light-weight buildings. PCMs have two important advantages as storage media: they can offer an order-of-magnitude increase in thermal storage capacity and their discharge is almost isothermal. This allows to store large amounts of energy without significantly changing the temperature of the sheathing. As heat storage takes place in the building part where the loads occur, rather than externally (e.g., ice or chilled water storage), additional transport energy is not needed. To numerically evaluate the latent storage performance of treated wallboard, RADCOOL, a thermal building simulation model based on the finite difference approach, will be used. RADCOOL has been developed in the SPARK environment in order to be compatible with the new family of simulation tools being developed at Lawrence Berkeley Laboratory. As logical statements are difficult to use in SPARK, a continuous function for the specific heat and the enthalpy had to be found. This report covers the development of a simplified description of latent storage characteristics for wallboard treated with phase change material.

  13. NONEQUILIBRIUM SULFUR CAPTURE & RETENTION IN AN AIR COOLED SLAGGING COAL COMBUSTOR

    SciTech Connect (OSTI)

    Bert Zauderer

    2003-04-21T23:59:59.000Z

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. The reacted particles impact and melt in the liquid slag layer on the combustor wall by the centrifugal force of the swirling combustion gases. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Prior analyses and laboratory scale data indicated that for Coal Tech's 20 MMBtu/hour, air-cooled, slagging coal combustor slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to validate this sulfur-in-slag model in a group of combustor tests. A total of 36 days of testing on the combustor were completed during the period of performance of this project. This was more that double the 16 test days that were required in the original work statement. The extra tests were made possible by cost saving innovations that were made in the operation of the combustor test facility and in additional investment of Coal Tech resources in the test effort. The original project plan called for two groups of tests. The first group of tests involved the injection of calcium sulfate particles in the form of gypsum or plaster of Paris with the coal into the 20 MMBtu/hour-combustor. The second group of tests consisted of the entire two-step process, in which lime or limestone is co-injected with coal and reacts with the sulfur gas released during combustion to form calcium sulfate particles that impact and dissolve in the slag layer. Since this sulfur capture process has been validated in numerous prior tests in this combustor, the primary effort in the present project was on achieving the high slag flow rates needed to retain the sulfur in the slag.

  14. The Martha Rivers Ingram Center for the Performing Arts Technical Specifications

    E-Print Network [OSTI]

    Bordenstein, Seth

    '-9" Depth of fixed stage ­ 37'-9" Height at Plaster line ­ *30'-0" Height at Back Wall - 24'-6" Shell doors'-0" Proscenium height ­ *31'-0" Floor Construction ­ Tongue & groove pine over sprung sleepers Depth from plaster line ­ 29'-5" Depth of apron to plaster line - 8"-4" Stage height from house floor- 3'-5" Stage right

  15. E-Print Network 3.0 - ant crematogaster ashmeadi Sample Search...

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

    ants Walter R. Tschinkel... Forel and A. ashmeadi (Emery), was studied from plaster, wax, or metal casts. After structural features... were quantified from digital...

  16. E-Print Network 3.0 - adult men determined Sample Search Results

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

    Mathematics 78 Development of Personality in Early and Middle Adulthood: Set Like Plaster or Persistent Change? Summary: studies of both men and women have directly compared...

  17. -A Science Servke Feacure Released upon receipt

    E-Print Network [OSTI]

    - Each drop thus makes a cast of i t s e l f , whichtaining drY flour o r plaster of Paris. is easily

  18. E-Print Network 3.0 - abscessed tooth patient Sample Search Results

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

    care during the three major School events. Celebration of Smiles More than 2... plaster molds, make tooth pillows, get their face (continued, right column) painted, and...

  19. E-Print Network 3.0 - artificial cranial deformation Sample Search...

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

    at Seattle Collection: Computer Technologies and Information Sciences 27 Validation of Plaster Endocast Morphology Through 3D CT Image Analysis Summary: and two Pan troglodytes...

  20. E-Print Network 3.0 - anal canal duplication Sample Search Results

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

    Siliconemolds are, of course, flexible duplicates of the original nodules. Dental plaster was poured into both... - sphenotic; dspo, exposed portion of sphenotic; Fr, frontal;...

  1. -A Science Service Feature Released uoon receipt

    E-Print Network [OSTI]

    s a plaster cast of the depo8it formed on a telephone mire during the New Jhgland ice s t o m of February

  2. Experiential Learning Spring Courses 2009 Note: This list emphasizes courses with few prerequisites but students should refer to the Bulletin

    E-Print Network [OSTI]

    Fraden, Seth

    to the very basics of 3D modeling with Cinema4D, rapid prototyping (3D printing with the Zcorp plaster printer

  3. E-Print Network 3.0 - acoustic insulation Sample Search Results

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

    , flues and tank insulation, decorative plaster finishes, car parts, sprayed on coatings and ... Source: Oliver, Douglas L. - Department of Neuroscience, University of...

  4. Accumulation and replacement of exchangeable sodium in soils of Southeast Texas under turfgrass and its effect on soil infiltration rate

    E-Print Network [OSTI]

    Aydemir, Salih

    2012-06-07T23:59:59.000Z

    in soils of this area. This study assessed the degree of Na accumulation on cation exchange sites as affected by gypsum treatments in soils that support turfgrass (bermudagrass) and the response of soil infiltration rate to different rates of gypsum...

  5. Effective masses for small nitrogen concentrations in InGaAsN alloys on GaAs

    SciTech Connect (OSTI)

    JONES,ERIC D.; ALLERMAN,ANDREW A.; KURTZ,STEVEN R.; FRITZ,IAN J.; MODINE,NORMAND A.; SIEG,ROBERT M.; BAJAJ,K.K.; TOZER,S.W.; WEI,X.

    2000-05-11T23:59:59.000Z

    The variation of the value of the linewidth of an excitonic transition in InGaAsN alloys (1% and 2% nitrogen) as a function of hydrostatic pressure using photoluminescence spectroscopy is studied at 4K. The excitonic linewidth increases as a function of pressure until about 100 kbar after which it tends to saturate. This pressure dependent excitonic linewidth is used to derive the pressure variation of the exciton reduced mass using a theoretical formalism based on the premise that the broadening of the excitonic transition is caused primarily by compositional fluctuations in a completely disordered alloy. The linewidth derived ambient pressure masses are compared and found to be in agreement with other mass measurements. The variation of this derived mass is compared with the results from a nearly first-principles approach in which calculations based on the local density approximation to the Kohn-Sham density functional theory are corrected using a small amount of experimental input.

  6. SIMULATIONS OF A HIGH POWER 4H-SiC VJFET AND ITS GaAs COUNTERPART

    E-Print Network [OSTI]

    Myles, Charles W.

    of the two devices. The two-dimensional simulations were carried out using the ATLAS simulator from Silvaco

  7. Perturbation of Au-assisted planar GaAs nanowire growth by p-type dopant impurities

    E-Print Network [OSTI]

    Li, Xiuling

    , Chen Zhang, Parsian K. Mohseni, Seth A. Fortuna, Jian-Guo Wen, James J. Coleman, and Xiuling Li-up assembly of large-area nanowire resonator arrays," Nat. Nanotechnol. 3(2), 88­92 (2008). 5. S. A. Fortuna Device Lett. 30(6), 593­595 (2009). 6. R. Dowdy, D. A. Walko, S. A. Fortuna, and X. Li, "Realization

  8. Projected Performance of Three- and Four-Junction Devices Using GaAs and GaInP

    E-Print Network [OSTI]

    Gainp; S. R. Kurtz; Sarah R. Kurtz; D. Myers; D. Myers; J.M. Olson; J. M. Olson

    1997-01-01T23:59:59.000Z

    This paper explores the efficiencies expected for three- and four-junction devices for both space and terrestrial applications. For space applications, the effects of temperature and low concentration are investigated. For terrestrial applications, a concentration of 500 suns is assumed and the theoretical efficiencies are calculated as a function of spectral variations including the effects of air mass, turbidity, and water-vapor content. INTRODUCTION Ga 0.5 In 0.5 P/GaAs two-terminal, two-junction solar cells, invented and developed at the National Renewable Energy Laboratory, are in production at both TECSTAR and Spectrolab. The immediate market for these devices is in space; a future (potentially larger) market is terrestrial concentrator systems. The next-generation cells will add additional junction(s) in order to increase the efficiency. Work on a three-junction cell using an active Ge junction under the Ga 0.5 In 0.5 P/GaAs dual-junction cell has already been reported [1]. Ho...

  9. Effect of quantum dot position and background doping on the performance of quantum dot enhanced GaAs solar cells

    SciTech Connect (OSTI)

    Driscoll, Kristina, E-mail: kmdsps@rit.edu; Bennett, Mitchell F.; Polly, Stephen J.; Forbes, David V.; Hubbard, Seth M., E-mail: smhsps@rit.edu [NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, New York (United States)

    2014-01-13T23:59:59.000Z

    The effect of the position of InAs quantum dots (QD) within the intrinsic region of pin-GaAs solar cells is reported. Simulations suggest placing the QDs in regions of reduced recombination enables a recovery of open-circuit voltage (V{sub OC}). Devices with the QDs placed in the center and near the doped regions of a pin-GaAs solar cell were experimentally investigated. While the V{sub OC} of the emitter-shifted device was degraded, the center and base-shifted devices exhibited V{sub OC} comparable to the baseline structure. This asymmetry is attributed to background doping which modifies the recombination profile and must be considered when optimizing QD placement.

  10. Epitaxial growth of Cu,,In,Ga...Se2 on GaAs,,110... and A. Rockett

    E-Print Network [OSTI]

    Rockett, Angus

    . INTRODUCTION The Cu(In, Ga)Se2 CIGS absorber layer in a recent record-efficiency CIGS solar cell1 has a 220.13 Commercially supplied ``epi-ready'' liquid- encapsulated Czo

  11. Growth Mechanism and Electronic Structure of Zn3P2 on the Ga-Rich GaAs(001) Surface

    E-Print Network [OSTI]

    Atwater, Harry

    as well as the potential for low-cost, thin-film fabrication make Zn3P2 a promising active material Zn3P2 films on III-V substrates unlocks a promising pathway toward high-efficiency, earth-abundant photovoltaic devices fabricated on reusable, single-crystal templates. The detailed chemical, structural

  12. Noncontact deep level photo-thermal spectroscopy: Technique and application to semi-insulating GaAs Wafers

    E-Print Network [OSTI]

    Mandelis, Andreas

    to high resistivity materials, since the Debye-Huckel length is too large several milli- meters for semi materials. In DLPTS, the thermal recovery of carriers after excita- tion is monitored by a subNoncontact deep level photo-thermal spectroscopy: Technique and application to semi-insulating Ga

  13. MOUSSES MINERALES A PERFORMANCES OPTIMISEES

    E-Print Network [OSTI]

    Boyer, Edmond

    of these gypsum foams are then assessed and compared to the ones obtained for cellular and hemp concrete. Physical

  14. Terahertz characterisation of building R. Piesiewicz, T. Kleine-Ostmann, N. Krumbholz,

    E-Print Network [OSTI]

    Mittleman, Daniel

    .e. window glass, plaster and pine wood in transmission geometry and calculate the reflection coefficients of window glass (d ¼ 2.84 mm), plaster (d ¼ 2.74 mm) and wood (d ¼ 3.68 mm). In transmission geometry we

  15. How to recycle asbestos containing materials (ACM)

    SciTech Connect (OSTI)

    Jantzen, C.M.

    2000-04-11T23:59:59.000Z

    The current disposal of asbestos containing materials (ACM) in the private sector consists of sealing asbestos wetted with water in plastic for safe transportation and burial in regulated land fills. This disposal methodology requires large disposal volumes especially for asbestos covered pipe and asbestos/fiberglass adhering to metal framework, e.g. filters. This wrap and bury technology precludes recycle of the asbestos, the pipe and/or the metal frameworks. Safe disposal of ACM at U.S. Department of Energy (DOE) sites, likewise, requires large disposal volumes in landfills for non-radioactive ACM and large disposal volumes in radioactive burial grounds for radioactive and suspect contaminated ACM. The availability of regulated disposal sites is rapidly diminishing causing recycle to be a more attractive option. Asbestos adhering to metal (e.g., pipes) can be recycled by safely removing the asbestos from the metal in a patented hot caustic bath which prevents airborne contamination /inhalation of asbestos fibers. The dissolution residue (caustic and asbestos) can be wet slurry fed to a melter and vitrified into a glass or glass-ceramic. Palex glasses, which are commercially manufactured, are shown to be preferred over conventional borosilicate glasses. The Palex glasses are alkali magnesium silicate glasses derived by substituting MgO for B{sub 2}O{sub 3} in borosilicate type glasses. Palex glasses are very tolerant of the high MgO and high CaO content of the fillers used in forming asbestos coverings for pipes and found in boiler lashing, e.g., hydromagnesite (3MgCO{sub 3} Mg(OH){sub 2} 3H{sub 2}O) and plaster of paris, gypsum (CaSO{sub 4}). The high temperate of the vitrification process destroys the asbestos fibers and renders the asbestos non-hazardous, e.g., a glass or glass-ceramic. In this manner the glass or glass-ceramic produced can be recycled, e.g., glassphalt or glasscrete, as can the clean metal pipe or metal framework.

  16. In situ metal-organic chemical vapor deposition atomic-layer deposition of aluminum oxide on GaAs using trimethyaluminum

    E-Print Network [OSTI]

    IPA is chosen as the oxygen source for the ALD in the MOCVD. Second, IPA will not react precursor pulse time. b Dependence of ALD Al2O3 growth rate on temperature. The pulse time for TMA and IPA

  17. Ralisation et caractrisation d'un transistor effet de champ JFET au GaAs en vue de son intgration avec une photodiode

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    intégration avec une photodiode M. T. Belaroussi, F. Therez et R. Alcubilla (*) Laboratoire d'Automatique et d étendus à la fabrication du circuit intégré GaAlAs-GaAs associant une photodiode à un TEC. Abstract. 2014AlAs-GaAs monolithic integration of a photodiode and FET. Revue Phys. Appl. 22 (1987) 77-82 JANVIER 1987

  18. 60 GHz Harmonic Optoelectronic Up-Conversion Using an InAlAs/InGaAs Metamorphic High-Electron-Mobility Transistor on a GaAs Substrate

    E-Print Network [OSTI]

    Choi, Woo-Young

    60 GHz Harmonic Optoelectronic Up-Conversion Using an InAlAs/InGaAs Metamorphic High optoelectronic up-conversion using an InAlAs/InGaAs metamorphic high-electron-mobility transistor (HEMT) on a Ga 1 GHz signals into a 60 GHz band. After investigating the dependences of optoelectronic mixing

  19. Growth of alternating (1OO)/(lll )-oriented II-VI regions for quasi-phase-matched nonlinear optical devices on GaAs substrates

    E-Print Network [OSTI]

    Fejer, Martin M.

    ferroelectrics such as lithium nio- bate and potassium titanyl phosphate. Efficient operation is possible) nonlinear interactions. II-VI semiconductors, with transparency from the far in- frared to the visible phasematched interactions.' A powerful alternative technique, QPM, re- quires periodic patterning of the sign

  20. Nuclear radiation detectors based on a matrix of ion-implanted p-i-n diodes on undoped GaAs epilayers

    SciTech Connect (OSTI)

    Baryshnikov, F. M.; Britvich, G. I.; Chernykh, A. V.; Chernykh, S. V.; Chubenko, A. P.; Didenko, S. I.; Koltsov, G. I. [National University of Science and Technology 'MISIS', Leninskiy prospect 4, 119049 Moscow (Russian Federation); Institute for High Energy Physics, Polshhad nauki 1, 142281 Protvino (Russian Federation); National University of Science and Technology 'MISIS', Leninskiy prospect 4, 119049 Moscow (Russian Federation); P.N. Lebedev Physical Institute of the RAS, Leninskiy prospect 53, 119991 Moscow (Russian Federation); National University of Science and Technology 'MISIS', Leninskiy prospect 4, 119049 Moscow (Russian Federation)

    2012-11-06T23:59:59.000Z

    Samples of nuclear detectors which represent matrices of p-i-n diodes were fabricated based on undoped gallium arsenide epitaxial layers by ion implantation technology. The detectors have a size of the active area of 0.4 Multiplication-Sign 0.4 and 0.9 Multiplication-Sign 0.9 cm{sup 2}. Electrical characteristics of fabricated detectors and results of measurements of fast neutrons spectra of {sup 241}Am-Be source by the recoil protons method are discussed.

  1. A quantitative conduction model for a low-resistance nonalloyed ohmic contact structure utilizing low-temperature-grown GaAs

    E-Print Network [OSTI]

    Woodall, Jerry M.

    A quantitative conduction model for a low-resistance nonalloyed ohmic contact structure utilizing properties of this material. The specific contact resistance is then calculated using an analytic expression for tunneling conduction through an equivalent uniformly doped Schottky barrier. The model has been used to fit

  2. Complementary GaAs Technology for High-Speed VLSI Circuits Richard B. Brown, Bruce Bernhardt*, Mike LaMacchia**, Jon Abrokwah***, Phiroze N. Parakh,

    E-Print Network [OSTI]

    Mudge, Trevor

    , Claude R. Gauthier, David Foster**, Brian Crawforth**, Timothy McQuire**, Karem Sakallah, Ronald J. Lomax

  3. Complementary GaAs Technology for HighSpeed VLSI Circuits Richard B. Brown, Bruce Bernhardt*, Mike LaMacchia**, Jon Abrokwah***, Phiroze N. Parakh,

    E-Print Network [OSTI]

    Mudge, Trevor

    , Claude R. Gauthier, David Foster**, Brian Crawforth**, Timothy McQuire**, Karem Sakallah, Ronald J. Lomax

  4. Critical size for the generation of misfit dislocations and their effects on electronic properties in GaAs nanosheets on Si substrate

    E-Print Network [OSTI]

    Southern California, University of

    -Queisser limit6 for the solar-cell efficiency. Recently, NWs of various semi- conductors such as GaAs/AlGaAs,7

  5. Growth, microstructure, and luminescent properties of direct-bandgap InAlP on relaxed InGaAs on GaAs substrates

    E-Print Network [OSTI]

    Beaton, D. A.

    Direct-bandgap InAlP alloy has the potential to be an active material in nitride-free yellow-green and amber optoelectronics with applications in solid-state lighting, display devices, and multi-junction solar cells. We ...

  6. E-Print Network 3.0 - af kronisk hepatitis Sample Search Results

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

    Mange kronisk syge bruger en stor del af deres tid p at vre koblet til... plaster. Det er opskriften p et bedre liv for kronisk syge, der hidtil har v- ret...

  7. E-Print Network 3.0 - af kronisk myeloid Sample Search Results

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

    Mange kronisk syge bruger en stor del af deres tid p at vre koblet til... plaster. Det er opskriften p et bedre liv for kronisk syge, der hidtil har v- ret...

  8. E-Print Network 3.0 - anmeldelse af kronisk Sample Search Results

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

    Mange kronisk syge bruger en stor del af deres tid p at vre koblet til... plaster. Det er opskriften p et bedre liv for kronisk syge, der hidtil har v- ret...

  9. E-Print Network 3.0 - active fault system Sample Search Results

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

    Summary: -8141(95)00105-0 Experimental modeling of extensional fault systems by use of plaster HAAKON FOSSEN Statoil, N-5020 Bergen... -scale structures in relation to larger fault...

  10. Method for the construction of x-ray shielding masks

    SciTech Connect (OSTI)

    Canup, D.; Ekstrand, K.E.

    1982-03-01T23:59:59.000Z

    A method is described for the production of a rigid model of a patient's face onto which lead shielding sheets may be contoured. The model is cast in Lipowitz's metal using a plaster mold.

  11. E-Print Network 3.0 - atypical wernicke encephalopathy Sample...

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

    the use of an auditory short- term memory task... with EEG features atypical for IGE.8 Plaster et al.10 recently reported gene localization of familial AME Source: Litt, Brian -...

  12. CP Tech Center I Iowa State University I 2711 S. Loop Dr. Suite 4700,Ames, IA 50010-8664 I 515-294-5798 FOR MORE INFORMATION

    E-Print Network [OSTI]

    CP Tech Center I Iowa State University I 2711 S. Loop Dr. Suite 4700,Ames, IA 50010-8664 I 515 calcium sulfate in the form of hemihydrate (plaster) in the cement (false set) or the uncontrolled early

  13. PAINTING CHECKLIST GETTING STARTED

    E-Print Network [OSTI]

    Peters, Richard

    Sanding block o Sandpaper in a variety of grades o Scraper for loose surfaces and paint o Putty and fillers for gaps and holes · caulk for joints · plaster filler for walls · wood putty for timber · epoxy

  14. THE CITY UNIVERSITY OF NEW YORK Classified Civil Service Position Description

    E-Print Network [OSTI]

    Rosen, Jay

    . - Applies plasters to surfaces. - Takes proper care of all materials, tools and equipment. - Keeps records as required. - May operate a motor vehicle in the performance as assigned duties. Qualification Requirements 1

  15. FEMA B-526 / March 2010 Important Numbers and Addresses

    E-Print Network [OSTI]

    Wilcock, William

    : _________________________________________________ ___________________________________________________________ Location of Disaster Supplies Kit, like toppling chimneys, falling bricks, ceiling plaster, and light fixtures. Many of these conditions. Consult your local Building Department if you are unsure of the earthquake hazard in your locale. Based on

  16. Stochastic versus Robust Optimization for a Transportation Problem

    E-Print Network [OSTI]

    Francesca Maggioni

    2015-03-05T23:59:59.000Z

    Mar 5, 2015 ... Abstract: In this paper we consider a transportation problem under uncertainty related to gypsum replenishment for a cement producer.

  17. Irrigation Water Quality Salinity Management

    E-Print Network [OSTI]

    Na2SO4 Moderate to large Calcium chloride CaCl2 Moderate Calcium sulfate (gypsum) CaSO4 2H2O Moderate

  18. The effect of inclusions in brittle material

    E-Print Network [OSTI]

    Janeiro, Raymond Pinho

    2009-01-01T23:59:59.000Z

    This thesis experimentally investigates the cracking behavior of brittle heterogeneous materials. Unconfined, uniaxial compression tests are conducted on prismatic gypsum specimens containing either one, or two, inclusions. ...

  19. Building Stones

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    Ancient Egyptian limestone quarries: A petrological survey.pp. 195 - 212. 2001 Ancient quarries near Amarna. Egyptian36 - 38. 2010 An early Roman quarry for anhydrite and gypsum

  20. Model Code for the Control of Residential HVAC Distribution System Leakage and HVAC-Induced Building Leakage

    E-Print Network [OSTI]

    Wemhoff, P.

    1990-01-01T23:59:59.000Z

    , Underwriters Laboratories, Inc., the Air Conditioning Contractors Of America, the Thermal Insulation Manufacturers Association, the National Fire Protection Association, and the Gypsum Association....

  1. GALLIUM--2002 29.1 References that include a section mark () are found in the Internet

    E-Print Network [OSTI]

    consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices application for gallium, with 46% of total consumption. Optoelectronic devices accounted for 42% of domestic

  2. doi: 10.1149/1.2108814 1986, Volume 133, Issue 6, Pages 1176-1179.J. Electrochem. Soc.

    E-Print Network [OSTI]

    Woodall, Jerry M.

    -Si/GaAs interfaces have been prepared by depositing hydrogenated amorphous Si (a-Si:H) onto GaAs in a silane plasma is the case for other lattice mismatched GaAs heterojunctions and most

  3. Photovoltaic Single-Crystalline, Thin-Film Cell Basics | Department...

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

    been developed for light-emitting diodes, lasers, and other electronic devices that use light. GaAs solar cells offer several benefits: The GaAs bandgap is 1.43 eV-nearly ideal...

  4. E-Print Network 3.0 - algainp light-emitting diodes Sample Search...

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

    by sequentially adding components of different types. Six hundred AlGaInP GaAs light- emitting diode segments... of 600 AlGaInP GaAs light-emitting diodes (LEDs) onto device...

  5. VOLUME 76, NUMBER 8 P H Y S I C A L R E V I E W L E T T E R S 19 FEBRUARY 1996 Spin Splitting of Single 0D Impurity States in Semiconductor Heterostructure Quantum Wells

    E-Print Network [OSTI]

    Reed, Mark

    cm23 Si doped GaAs contact, a 15 nm undoped GaAs spacer layer, a 8.5 nm undoped Al0.27Ga0.73As bottom GaAs spacer layer, and a 1.8 3 1018 cm23 Si doped GaAs top contact. Square mesas with lateral dimensions from 2 to 64 mm are fabricated using standard photolithography techniques. Two terminal I V

  6. Separation of flue-gas scrubber sludge into marketable products

    SciTech Connect (OSTI)

    Kawatra, S.K.; Eisele, T.C.

    1997-08-31T23:59:59.000Z

    A tremendous amount of wet flue-gas desulfurization scrubber sludge (estimated 20 million metric tons per year in the US) is currently being landfilled at a huge cost to utility companies. Scrubber sludge is the solid precipitate produced during desulfurization of flue-gas from burning high sulfur coal. The amount of this sludge is expected to increase in the near future due to ever increasing governmental regulation concerning the amount of sulfur emissions. Scrubber sludge is a fine, grey colored powder that contains calcium sulfite hemihydrate (CaSO{sub 3} {center_dot} 1/2H{sub 2}), calcium sulfate dihydrate (CaSO{sub 4} {center_dot} 2H{sub 2}O), limestone (CaCO{sub 3}), silicates, and iron oxides. This material can continue to be landfilled at a steadily increasing cost, or an alternative for utilizing this material can be developed. This study explores the characteristics of a naturally oxidized wet flue-gas desulfurization scrubber sludge and uses these characteristics to develop alternatives for recycling this material. In order for scrubber sludge to be used as a feed material for various markets, it was necessary to process it to meet the specifications of these markets. A physical separation process was therefore needed to separate the components of this sludge into useful products at a low cost. There are several physical separation techniques available to separate fine particulates. These techniques can be divided into four major groups: magnetic separation, electrostatic separation, physico-chemical separation, and density-based separation. The properties of this material indicated that two methods of separation were feasible: water-only cycloning (density-based separation), and froth flotation (physico-chemical separation). These processes could be used either separately, or in combination. The goal of this study was to reduce the limestone impurity in this scrubber sludge from 5.6% by weight to below 2.0% by weight. The resulting clean calcium sulfite/sulfate material can be oxidized into a synthetic gypsum that can be used in several markets which include: wallboard manufacturing, plaster, portland cement, and as a soil conditioner. Single stage water-only cycloning removed nearly 50% of the limestone by weight from the scrubber sludge and maintained a weight recovery of 76%. Froth flotation produced a calcium sulfite/sulfate that contained 4.30% limestone by weight with a 71% weight recovery. These methods were successful in removing some of the limestone impurity, but were not able to meet the specifications needed. However, the combination of water-only cycloning and froth flotation provided a clean, useful calcium sulfite/sulfate material with a limestone grade of 1.70% by weight and a total weight recovery of nearly 66%.

  7. Subcriticality measurements for coupled uranium metal cylinders using the /sup 252/Cf-source-driven neutron noise analysis method

    SciTech Connect (OSTI)

    Mihalezo, J.T.; King, W.T.; Blakeman, E.D.

    1987-01-01T23:59:59.000Z

    Experiments performed with two coupled uranium metal cylinders are the first application to coupled systems of the /sup 252/Cf-source-driven neutron noise analysis method for obtaining the subcritical neutron multiplication factor. These coaxial cylinders were separated axially by various thicknesses of either air or borated plaster between the flat surfaces. In all measurements, the /sup 252/Cf neutron source was located at the center of the outer flat surface of one cylinder, and the two detectors were located in three configurations. By comparing the subcriticality from the measurements performed with borated plaster separating the uranium cylinders to those separated by air, it was found that the neutron multiplication factor was always increased by the insertion of borated plaster between the cylinders, regardless of their separation.

  8. Elden Tefft: An Informal Look at a Founding Father of Twentieth Century Bronze Casting in the United States

    E-Print Network [OSTI]

    Voorhees, Craig

    2011-07-29T23:59:59.000Z

    melts and runs out down a hole left in the bottom of the mold. This leaves a hollow in the dried plaster in exactly the same shape left by the wax model. The hole in the bottom of the mold is then plugged up and melted bronze is poured into the mold... and the bronze solidifies in the hollow left behind in the plaster when the wax melted and ran out. The lost wax process gets its name because the wax disappears when the mold is heated. Using the lost wax casting technique, large and complex sculptures can...

  9. Covering Walls With Fabrics.

    E-Print Network [OSTI]

    Anonymous,

    1979-01-01T23:59:59.000Z

    the glue a dull surface to adhere to. Fill any gouges or nail holes with patching plaster and sand smooth after they have dried thoroughly. Minor ripples can be covered with spackling compound, a plaster-like substance that is spread thinly... during dry weather and in a well-ventilated room. Cut each panel 3 inches longer than the ceiling height. Match and cut sufficient fabric widths to cover completely one wall at a time. Start with Corner I nstall the first fabric panel so...

  10. Indirect excitons in GaAs coupled quantum wells : development of optoelectronic logic devices and trapping potentials, and studies of low temperature phenomena in a bosonic condensed matter system

    E-Print Network [OSTI]

    High, Alexander Arthur; High, Alexander Arthur

    2012-01-01T23:59:59.000Z

    the develop- ment of optoelectronics but also in the studiesof exciton based optoelectronics, that of scalability, willin exciton-based optoelectronics have been made. This

  11. GaAs Nanowire Array Solar Cells with Axial p-i-n Junctions Maoqing Yao, Ningfeng Huang, Sen Cong, Chun-Yung Chi, M. Ashkan Seyedi, Yen-Ting Lin, Yu Cao,

    E-Print Network [OSTI]

    Zhou, Chongwu

    for future low-cost, high-efficiency photovoltaics. KEYWORDS: Nanowires, solar cells, gallium arsenide, axial.58% efficiency. Simulations show that axial junctions are more tolerant to doping variation than radial junctions and shallow junctions are essential for a high extraction efficiency. Our approach opens up great opportunity

  12. VOLUME 78, NUMBER 2 P H Y S I C A L R E V I E W L E T T E R S 13 JANUARY 1997 Observation of Coherently Controlled Photocurrent in Unbiased, Bulk GaAs

    E-Print Network [OSTI]

    Van Driel, Henry M.

    -charge fields and enhanced second-harmonic generation in optical fibers [7]. Although the results in LT-GaAs are measured for injected carrier densities as low as 1014 cm23 and for peak irradiances.50.Ar, 42.65.­k The idea of controlling optical, physical, and chemical processes in matter using

  13. Summary Abstract: The MBE growth of GaAs free of oval defects G. D. Pettit, J. M. Woodall, S. L. Wright, P. D. Kirchner, and J. L. Freeouf

    E-Print Network [OSTI]

    Woodall, Jerry M.

    . Wright, P. D. Kirchner, and J. L. Freeouf IBM Thomas J. Watson Research Center, Yorktown Heights, New

  14. Luminescence properties of light-emitting diodes based on GaAs with the up-conversion Y{sub 2}O{sub 2}S:Er,Yb luminophor

    SciTech Connect (OSTI)

    Gruzintsev, A. N., E-mail: gran@ipmt-hpm.ac.ru [Russian Academy of Sciences, Institute of Problems of Microelectronics Technology (Russian Federation); Barthou, C.; Benalloul, P. [Institute des NanoSciences (France)

    2008-03-15T23:59:59.000Z

    Y{sub 2}O{sub 2}S luminophors doped with Er{sup 3+} and Yb{sup 3+} ions are produced by means of solid-phase synthesis and deposited onto standard AL123A infrared light-emitting diodes. When excited with 940 nm radiation from a light-emitting diode, the structures exhibit intense visible up-conversion luminescence. A maximal brightness of 2340 cd/m{sup 2} of green and red up-conversion luminescence at corresponding wavelengths around 550 and 600 nm is observed for the Y{sub 2}O{sub 2}S compound doped with 2 at % Er{sup 3+} ions and 6 at % Yb{sup 3+} ions. The ratio of the intensity of green (or red) up-conversion luminescence to the intensity of infrared Stokes luminescence increases with increasing applied voltage. The efficiency of visible emission of the light-emitting diode structures is {eta} = 1.2 lm/W at an applied voltage of 1.5 V.

  15. Incorporating on-line process data into a diagnostic knowledge-based system

    E-Print Network [OSTI]

    Lin, Kai Hsuan

    1994-01-01T23:59:59.000Z

    The objective of this research was to develop and implement an on-line gypsum wallboard manufacturing expert system incorporating on-line process monitoring information and statistical process control. In support of this objective, several sub...

  16. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research

    E-Print Network [OSTI]

    Paytan, Adina

    of Geology and Environmental Geosciences, Northern Illinois University, Davis Hall 312, DeKalb, IL 60115, USA Chetumal, Quintana Roo to Campeche, Campeche. The presence of gypsum quarries in the area is also

  17. Continuing Education and Training Needs of the Southern Forest Industry.

    E-Print Network [OSTI]

    Thomas, John K.; Albrecht, Don E.; Lee, J. Charles; Klinoff, Roger

    1985-01-01T23:59:59.000Z

    and Paper Champion International Kirby Forest Industries Louisiana -Pacific Owens Illinois Temple EasTex Bear Island Paper Chesapeake Owens Illinois Union Camp United States Gypsum V irginia Fibr~ Westvaco CSX Resources Westvaco 13 14...

  18. Effects of tunneling on groundwater flow and swelling of clay-sulfate rocks

    E-Print Network [OSTI]

    Butscher, Christoph

    [1] Swelling of clay-sulfate rocks is a major threat in tunneling. It is triggered by the transformation of the sulfate mineral anhydrite into gypsum as a result of water inflow in anhydrite-containing layers after tunnel ...

  19. Environmental chamber measurements of mercury flux from coal utilization by-products

    SciTech Connect (OSTI)

    Pekney, N.J.; Martello, D.V.; Schroeder, K.T.; Granite, E.J.

    2009-05-01T23:59:59.000Z

    An environmental chamber was constructed to measure the mercury flux from coal utilization by-product (CUB) samples. Samples of fly ash, FGD gypsum, and wallboard made from FGD gypsum were tested under both dark and illuminated conditions with or without the addition of water to the sample. Mercury releases varied widely, with 7-day experiment averages ranging from -6.8 to 73 ng/m2 h for the fly ash samples and -5.2 to 335 ng/m2 h for the FGD/wallboard samples. Initial mercury content, fly ash type, and light exposure had no observable consistent effects on the mercury flux. For the fly ash samples, the effect of a mercury control technology was to decrease the emission. For three of the four pairs of FGD gypsum and wallboard samples, the wallboard sample released less (or absorbed more) mercury than the gypsum.

  20. Building Stones

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    anhydrite and gypsum near Wadi el-Anbaut, Red Sea coast,West Bank (ED:3; small) Wadi Rayan Formation of the MokattamNK & Pt-R? ; medium) 21. in Wadi Sheikh Yasin east of Zawyet

  1. A New Concept in Dryer Control

    E-Print Network [OSTI]

    Robinson, J. W.

    , lumber, fiberboard, gypsum board, crumb rubber, etc. In addition, such dryer types as Rotary Drum, Suspension, Flash, Through, Spray, Oven, Tray, Lime Kilns, etc., should be amenable to control utilizing this model. Moreover, it should apply to most thin...

  2. Journal of California and Great Basin Anthropology | Vol. 32, No. 1 (2012) | pp. 4764 Chemical Composition, Mineralogy,

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    Composition, Mineralogy, and Physical Structure of Pigments on Arrow and Dart Fragments from Gypsum Cave), and electron microprobe (EM) to determine their chemical composition, mineralogy, and physical structure pigments. Although variation in composition and mineralogy suggests some degree of experimentation

  3. Urban Form Energy Use and Emissions in China: Preliminary Findings and Model Proof of Concept

    E-Print Network [OSTI]

    Aden, Nathaniel

    2011-01-01T23:59:59.000Z

    producing building materials, but it does not include upstream requirements of energyenergy required for producing the water, limestone, sandstone, gypsum, and clay typically used for cement production. The building

  4. E-Print Network 3.0 - acute low-level microwave Sample Search...

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

    of California at San Diego Collection: Engineering 5 2picosecond, GaAs photodiode optoelectronic circuit for optical correlation applications Summary: diode that serves as the...

  5. E-Print Network 3.0 - absorption coefficient based Sample Search...

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

    67 Optical nonlinearity in low-temperature-grown GaAs: Microscopic limitations and optimization strategies Summary: is the absorption coefficient, d the physical thickness of the...

  6. 2070 OPTICS LETTERS / Vol. 29, No. 17 / September 1, 2004 400-photon-per-pulse ultrashort pulse autocorrelation

    E-Print Network [OSTI]

    Purdue University

    -photon absorption in silicon avalanche photodiodes,3 GaAs photomultiplier tubes,4 and InGaAsP laser diodes.5

  7. E-Print Network 3.0 - advanced technology large-aperture Sample...

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

    (Advanced Photonix). These diodes were chosen for two reasons. First... pulsed terahertz emitter, a large-aperture GaAs photoconductive switch, is carried out. It is...

  8. Transcending QCD in Nanostructured Solar Cells G. Galli S. Kauzlarich

    E-Print Network [OSTI]

    achieved! - But: fracking of natural gas moved grid parity to 0.3$/W 2. Science/Technology: - GaAs: 29% lab

  9. Decoupling of uranium metal with borated plast using /sup 252/Cf noise analysis methods

    SciTech Connect (OSTI)

    Mihalczo, J.T.; King, W.T.; Blakeman, E.D.

    1985-11-01T23:59:59.000Z

    The use of borated plaster to isolate uranium (93.2 wt % /sup 235/U) metal was studied in a series of subcritical experiments with uranium metal cylinders (7.0 in. in diameter and 2.0 in. thick) and slabs (approx. 1.4 x approx. 5.4 x approx. 10.1 in. dimensions). In the cylindrical experiments, the thickness of borated plaster was varied up to 10 in. and the subcriticality measured using the /sup 252/Cf-source-driven neutron noise analysis method. In the experiments with the uranium slabs, an array of slabs three wide and eight high was assembled in steps to demonstrate the subcriticality of this array with 3.75-in.-thick borated plaster as an isolating material between all uranium slabs. In the slab experiments, both noise analysis and source neutron multiplication measurements were performed. Before assembly of the slab array, the presence of boron in the plaster was verified by neutron transmission and gamma-ray spectrometry measurements.

  10. HIPed carbon fiber reinforced silicon nitride composites

    SciTech Connect (OSTI)

    Lundberg, R.; Pompe, R.; Carlsson, R.

    1988-08-01T23:59:59.000Z

    Carbon fiber/Si3N4 composites were fabricated using slip infiltration of fiber bundles subsequently stacked in a plaster mold, dried, glass encapsulated, and HIPed to form unidirectional composite test bars. Neither chemical reactions between fiber and matrix nor thermal mismatch cracks in the matrix were observed. The bend fracture behavior of the composites was nonbrittle with extensive fiber pullout. 14 references.

  11. Method of grouting a drill hole

    SciTech Connect (OSTI)

    Kennedy-Skipton, H.K.

    1980-12-02T23:59:59.000Z

    Calcium sulphate hemihydrate plaster slurry comprising a setinhibiting agent, for example, a polymer or copolymer of an acid having the formula r1hc=cr2-cooh wherein r1 and r2 are hydrogen or methyl. The invention also includes a method of rapid setting of the inhibited slurry by mixing therewith a promoter comprising a salt of iron, copper or aluminium.

  12. Spring Semester 2013 Courses, Independent Studio

    E-Print Network [OSTI]

    Spring Semester 2013 Courses, Independent Studio and Workshops 13 week term: January 28 - April 27.fas.harvard.edu/ceramics #12;Ceramics Program Spring 2013 Course Offerings January 28 - April 27, 2013 Beginning - Advanced and hard slabs, plaster molds and coil building. Collective Perspective Instructor: Delanie Wise

  13. MIXING AND CHAOTIC MICROSTRUCTURE \\Lambda Yuefan Deng and James Glimm y

    E-Print Network [OSTI]

    New York at Stoney Brook, State University of

    will fall. However, it is not through lack of support from the air that the water falls. The pressure the ceiling of a room plastered uniformly with water to a depth of 1 meter (Figure 1). The layer of water of the atmosphere is equivalent to that of a layer of water 10 meters thick, quite suffic

  14. Community Geothermal Technology Program: Silica bronze project. Final report

    SciTech Connect (OSTI)

    Bianchini, H.

    1989-10-01T23:59:59.000Z

    Objective was to incorporate waste silica from the HGP-A geothermal well in Pohoiki with other refractory materials for investment casting of bronze sculpture. The best composition for casting is about 50% silica, 25% red cinders, and 25% brick dust; remaining ingredient is a binder, such as plaster and water.

  15. Hillside C-type Renovation Issues and Remedies

    E-Print Network [OSTI]

    California at Berkeley, University of

    concrete and masonry Overhang Outside Inside Tiles Outer Alu frame Drill drain holes here throughout length Exterior wall bricks concrete and masonry Stone slab does not cover sill width Drain channel Outer Alu with new Marbonite ­ Concealing pipes Stone up to guiderail Porous cracked plaster outside #12;To Deputy

  16. Evaluating biological control of fire ants using phorid flies: effects on competitive interactions

    E-Print Network [OSTI]

    Mottern, Jason Lewis

    2002-01-01T23:59:59.000Z

    500 P. 15 tricuspis pupae were shipped weekly until the completion of the experiments. Pupae arrived in 59. 2-ml plastic souffles cups (Solo Cup Company, Urbana, IL) filled with white plaster to retain moisture. As the shipments arrived, pupae were...

  17. Architectural Structures Beijing Olympic Stadium 2008 as Biomimicry of a Bird's Nest

    E-Print Network [OSTI]

    Barthelat, Francois

    Architectural Structures ARCH 251 Beijing Olympic Stadium 2008 as Biomimicry of a Bird's Nest Ann: Bird's Nest 5 Figure 2 Rendering of interior concourse - Beijing National Stadium 8 Figure 3 CAD model welding of steel structure of the Bird's Nest 10 Figure 7 Maasai woman of Kenya plasters dung over her

  18. GOVERNING COUNCIL Asbestos Management Policy

    E-Print Network [OSTI]

    Boonstra, Rudy

    in building materials prior to 1980 because of its heat- resistant, chemical-resistant and insulative-being of its employees, students, visitors and contractors. Asbestos, a fibrous material commonly used, insulation around piping and mechanical equipment, thermal and acoustic boards, plasters, asbestos cement

  19. Potential Health Risks The same properties that make asbestos

    E-Print Network [OSTI]

    Loudon, Catherine

    , and strong. Its high tensile strength, heat and chemical resistance, flexibility, and good frictional materials: Surfacing materials- such as fireproofing, plaster Thermal system insulation- such as pipe wrap properties have made it an ideal material to meet the demands of an increasingly industrial world. Asbestos

  20. ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton GIT 2009

    E-Print Network [OSTI]

    Colton, Jonathan S.

    Air (oxygen), vacuum, inert gas (argon) Heating External - electric, gas, oil Internal Prof. J.S. Colton GIT 2009 11 Processes Sand Shell Plaster Ceramic Investment Lost foam Metals processed by casting Sand casting 60% Investment casting 7% Die casting 9% Permanent

  1. Method of making suspended thin-film semiconductor piezoelectric devices

    DOE Patents [OSTI]

    Casalnuovo, Stephen A. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM)

    2001-01-01T23:59:59.000Z

    A process for forming a very thin suspended layer of piezoelectric material of thickness less than 10 microns. The device is made from a combination of GaAs and AlGaAs layers to form either a sensor or an electronic filter. Onto a GaAs substrate is epitaxially deposited a thin (1-5 micron) sacrificial AlGaAs layer, followed by a thin GaAs top layer. In one embodiment the substrate is selectively etched away from below until the AlGaAs layer is reached. Then a second selective etch removes the sacrificial AlGaAs layer, that has acted here as an etch stop, leaving the thin suspended layer of piezoelectric GaAs. In another embodiment, a pattern of small openings is etched through the thin layer of GaAs on top of the device to expose the sacrificial AlGaAs layer. A second selective etch is done through these openings to remove the sacrificial AlGaAs layer, leaving the top GaAs layer suspended over the GaAs substrate. A novel etchant solution containing a surface tension reducing agent is utilized to remove the AlGaAs while preventing buildup of gas bubbles that would otherwise break the thin GaAs layer.

  2. 1204 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 34, NO. 9, SEPTEMBER 1999 Breakdown in Millimeter-Wave Power InP

    E-Print Network [OSTI]

    del Alamo, Jess A.

    1204 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 34, NO. 9, SEPTEMBER 1999 Breakdown in Millimeter-Wave Power InP HEMT's: A Comparison with GaAs PHEMT's J. A. del Alamo and M. H. Somerville Abstract's) deliver lower output power than GaAs pseudomorphic HEMT's (PHEMT's) throughout most of the millimeter

  3. GALLIUM--2000 30.1 By Deborah A. Kramer

    E-Print Network [OSTI]

    the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 63% of total consumption. Optoelectronic devices accounted for 32% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

  4. GALLIUM--1998 29.1 By Deborah A. Kramer

    E-Print Network [OSTI]

    's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 45% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

  5. GALLIUM--2003 28.1 References that include a section mark () are found in the Internet

    E-Print Network [OSTI]

    in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices (LEDs, laser diodes, photodetectors, and solar cells) and ICs. ICs and optoelectronic devices each accounted for 41) and optoelectronic devices [mostly laser diodes and light- emitting diodes (LEDs)]. Estimated crude gallium

  6. GALLIUM--1999 29.1 By Deborah A. Kramer

    E-Print Network [OSTI]

    circuits (IC's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 42% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

  7. INSTITUTE OF PHYSICS PUBLISHING SEMICONDUCTOR SCIENCE AND TECHNOLOGY Semicond. Sci. Technol. 22 (2007) 2934 doi:10.1088/0268-1242/22/2/006

    E-Print Network [OSTI]

    2007-01-01T23:59:59.000Z

    INSTITUTE OF PHYSICS PUBLISHING SEMICONDUCTOR SCIENCE AND TECHNOLOGY Semicond. Sci. Technol. 22 mismatch between Si and direct bandgap IIIV compound semiconductors such as GaAs makes the direct growth of compositionally graded Si1-xGex buffer layers to bridge the gap between Si and GaAs lattice constants (i

  8. Shot noise in self-assembled InAs quantum dots A. Nauen,1,

    E-Print Network [OSTI]

    Hohls, Frank

    they pro- vide zero-dimensional states of microscopic dimensions. Furthermore, it is possible to select structure of 40 40 m2 area. A 15 nm undoped GaAs spacer layer and a GaAs buffer with graded doping on both

  9. Passively modelocked 832 nm vertical-external-cavity surface-emitting

    E-Print Network [OSTI]

    Keller, Ursula

    , focused into an optical spot with dimensions of 100 ? 200 mm. The SESAM consisted of an AlAs/Al0.2Ga0.8As DBR, a spacer layer of GaAs0.75P0.25, a 4.8 nm GaAs quantum well and a 2 nm-thick capping layer of Ga

  10. Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology. Annual subcontract report, 1 August 1991--31 July 1992

    SciTech Connect (OSTI)

    Vernon, S.M. [Spire Corp., Bedford, MA (United States)

    1993-04-01T23:59:59.000Z

    This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, {approximately} 1 {times} 10{sup 5} cm{sup {minus}5}, as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 {times}10{sup 7} cm{sup {minus}2}. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

  11. Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology

    SciTech Connect (OSTI)

    Vernon, S.M. (Spire Corp., Bedford, MA (United States))

    1993-04-01T23:59:59.000Z

    This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, [approximately] 1 [times] 10[sup 5] cm[sup [minus]5], as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 [times]10[sup 7] cm[sup [minus]2]. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

  12. Macroscopic corrosion front computations of sulfate attack in sewer pipes based on a micro-macro reaction-diffusion model

    E-Print Network [OSTI]

    Chalupeck, Vladimr; Kruschwitz, Jens; Muntean, Adrian

    2012-01-01T23:59:59.000Z

    We consider a two-scale reaction diffusion system able to capture the corrosion of concrete with sulfates. Our aim here is to define and compute two macroscopic corrosion indicators: typical pH drop and gypsum profiles. Mathematically, the system is coupled, endowed with micro-macro transmission conditions, and posed on two different spatially-separated scales: one microscopic (pore scale) and one macroscopic (sewer pipe scale). We use a logarithmic expression to compute values of pH from the volume averaged concentration of sulfuric acid which is obtained by resolving numerically the two-scale system (microscopic equations with direct feedback with the macroscopic diffusion of one of the reactants). Furthermore, we also evaluate the content of the main sulfatation reaction (corrosion) product---the gypsum---and point out numerically a persistent kink in gypsum's concentration profile. Finally, we illustrate numerically the position of the free boundary separating corroded from not-yet-corroded regions.

  13. Scanning probe microscopy: Sulfate minerals in scales and cements

    SciTech Connect (OSTI)

    Hall, C. [Schlumberger Cambridge Research (United Kingdom)

    1995-11-01T23:59:59.000Z

    The principles of scanning probe microscopy (SPM) are illustrated with examples from oilfield mineralogy, particularly emphasizing sulfate minerals involved in scale formation and cement hydration chemistry. The topography of the (010) cleavage surface of gypsum observed by atomic force microscopy shows atomically flat terraces separated by shallow steps often only one unit cell high. SPM allows direct observation of processes on mineral surfaces while they are in contact with solutions. The dissolution etching and crystal growth of gypsum and barite are discussed and rates of step migration estimated. The orientation of steps is related to the crystallographic axes. The action of phosphonate crystal growth inhibitor on gypsum and of a chelating scale solvent on barite are also shown. The multiphase microstructure of an oilwell cement clinker is described in relation to its hydration chemistry in contact with water and its reaction with sulfate ions.

  14. Advanced Flue Gas Desulfurization (AFGD) demonstration project: Volume 2, Project performance and economics. Final technical report

    SciTech Connect (OSTI)

    NONE

    1996-04-30T23:59:59.000Z

    The project objective is to demonstrate removal of 90--95% or more of the SO{sub 2} at approximately one-half the cost of conventional scrubbing technology; and to demonstrate significant reduction of space requirements. In this project, Pure Air has built a single SO{sub 2} absorber for a 528-MWe power plant. The absorber performs three functions in a single vessel: prequencher, absorber, and oxidation of sludge to gypsum. Additionally, the absorber is of a co- current design, in which the flue gas and scrubbing slurry move in the same direction and at a relatively high velocity compared to conventional scrubbers. These features all combine to yield a state- of-the-art SO{sub 2} absorber that is more compact and less expensive than conventional scrubbers. The project incorporated a number of technical features including the injection of pulverized limestone directly into the absorber, a device called an air rotary sparger located within the base of the absorber, and a novel wastewater evaporation system. The air rotary sparger combines the functions of agitation and air distribution into one piece of equipment to facilitate the oxidation of calcium sulfite to gypsum. Additionally, wastewater treatment is being demonstrated to minimize water disposal problems inherent in many high-chloride coals. Bituminous coals primarily from the Indiana, Illinois coal basin containing 2--4.5% sulfur were tested during the demonstration. The Advanced Flue Gas Desulfurization (AFGD) process has demonstrated removal of 95% or more of the SO{sub 2} while providing a commercial gypsum by-product in lieu of solid waste. A portion of the commercial gypsum is being agglomerated into a product known as PowerChip{reg_sign} gypsum which exhibits improved physical properties, easier flowability and more user friendly handling characteristics to enhance its transportation and marketability to gypsum end-users.

  15. A detailed spectroscopic study of an Italian fresco

    SciTech Connect (OSTI)

    Barilaro, Donatella; Crupi, Vincenza; Majolino, Domenico; Barone, Germana; Ponterio, Rosina [Dipartimento di Fisica and Instituto Nazionale per la Fisica della Materia (INFM), Universita di Messina, Contrada Papardo, Salita Sperone 31, P.O. Box 55, 98166 Messina (Italy); Dipartimento di Scienze dalla Terra, Universita di Messina, Contrada Papardo, Salita Sperone 31, P.O. Box 55, 98166 Messina (Italy); Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (CNR-IPCF), Sezione di Messina, Via La Farina 237, 98123 Messina (Italy)

    2005-02-15T23:59:59.000Z

    In the present work we characterized samples of plasters and pictorial layers taken from a fresco in the Acireale Cathedral. The fresco represents the Coronation of Saint Venera, patron saint of this Ionian town. By performing a detailed spectroscopic analysis of the plaster preparation layer by Fourier-transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD), and of the painting layer by FTIR and confocal Raman microspectroscopy, scanning electron microscopy+energy dispersive x-ray spectroscopy, and XRD, we were able to identify the pigments and the binders present. In particular, Raman investigation was crucial to the characterization of the pigments thanks to the high resolution of the confocal apparatus used. It is worth stressing that the simultaneous use of complementary techniques was able to provide more complete information for the conservation of the artifact we studied.

  16. Fragment Mass Distribution of Platelike Objects

    SciTech Connect (OSTI)

    Kadono, T. [Institute of Space and Astronautical Science, Kanagawa 229 (Japan)] [Institute of Space and Astronautical Science, Kanagawa 229 (Japan); [and Department of Physics, Kyoto University, Kyoto 606 (Japan)

    1997-02-01T23:59:59.000Z

    The fragment mass distributions of platelike objects are investigated by conducting two types of experiments. The first is a {open_quotes}sandwich{close_quote}{close_quote} experiment in which thin glass and plaster plates are inserted between two larger stainless steel plates and an iron projectile is dropped onto the target plate at normal incidence. The second is a {open_quotes}lateral impact{close_quote}{close_quote} experiment in which a hypervelocity nylon projectile collides at the side of the plaster plates. There is a discrepancy in the power-law exponent of fragment mass distribution between the sandwich experiment and the lateral impact experiment. A model that agrees with the experimental results is proposed. {copyright} {ital 1997} {ital The American Physical Society}

  17. Study of photon attenuation coefficients of some multielement materials. [123-1250 keV

    SciTech Connect (OSTI)

    Bhandal, G.S. (N.J.S.A. Government Coll., Punjab (India)); Singh, K. (Guru Nanak Dev Univ., Amritsar (India). Dept. of Physics)

    1994-03-01T23:59:59.000Z

    Total photon mass attenuation of six multielement shielding materials (concrete, plaster of paris, quick lime, black cement, white cement, and silica) is measured in the 123- to 1,250-keV energy range. The experimental results are analyzed in terms of cross sections, effective atomic numbers, and electron densities. Considerable sensitivity of the total mass attenuation coefficients and effective atomic numbers to variations in oxygen content are found in these multielement materials.

  18. Calculation of safe parameters of air shock waves for underwater explosions

    SciTech Connect (OSTI)

    Smolii, N.I.; Ganopol'skii, M.I.

    1985-07-01T23:59:59.000Z

    The paper proposes a functional relationship for the calculation of the pressure at an air shock-wave front in underwater explosions of plaster-blasting charges. The maximum permissible mass of the charge and safe distance for objects can be calculated for an assigned value of the critical pressure at the air shock-wave front. The authors also state that this work was conducted as there are practically no significant results of experimental or theoretical investigations of this problem.

  19. Possibilities of coke manufacture in nonpollutant conditions

    SciTech Connect (OSTI)

    Barca, F.; Panaitescu, C.; Vidrighin, C.; Peleanu, I. [Politehnica Univ. Bucharest (Romania); Albastroiu, P. [S.C. ICEM S.A., Bucharest (Romania)

    1994-12-31T23:59:59.000Z

    The paper presents some possibilities to obtain coke briquettes from anthracite, using as binders petroleum pitch, wheat flour, cement, plaster, ashes from power-plants dried from the electrofilters. Specific thermal post-treatment were proposed for each case, such as: oxidation or heating at low temperatures (under 300 C). As a result the authors obtained coke briquettes to be used in small equipment, with no pollutant pyrogenetic treatment.

  20. Imperial Reservoir KOFA NATIONAL

    E-Print Network [OSTI]

    Laughlin, Robert B.

    247 79 79 7 115 62 72 78 79 86 115 163 18 72 74 78 115 18 62 95 371 95 94 247 Solar Energy Study Areas of 7/21/2009) Solar Energy Study Area (as of 6/5/2009) BLM Lands Being Analyzed for Solar Development Imperial Plaster City Live Oak Springs Seeley Coyote Wells El Centro Holtville Boulevard Campo Tecate Heber

  1. Nano-scale characterization of GaAsP/GaAs strained superlattice structure by nano-beam electron diffraction

    SciTech Connect (OSTI)

    Jin, Xiuguang [Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Nakahara, Hirotaka [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Saitoh, Koh; Tanaka, Nobuo [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Takeda, Yoshikazu [Nagoya Industrial Science Research Institute, Nagoya 464-0819 (Japan); Aichi Synchrotron Radiation Center, Aichi Science and Technology Foundation, Seto 489-0965 (Japan)

    2014-03-17T23:59:59.000Z

    Distribution of lattice strain in a GaAsP/GaAs superlattice with a periodicity of 10?nm thickness, deposited on a 100?nm GaAs basal layer has been measured by nano-beam electron diffraction. The superlattice on the (001) plane of the basal GaAs layer shows a constant lattice strain from the bottom to the top layers, whereas the superlattice on the basal GaAs surface sloped by 16 from the (001) plane shows a variation of the lattice strain and crystal orientation. The difference of the strain distributions was discussed from the viewpoint of average strain. This tilt was explained by an atomistic model.

  2. DEDALOS NREL: Cooperative Research and Development Final Report, CRADA Number CRD-07-237

    SciTech Connect (OSTI)

    Friedman, D.

    2013-06-01T23:59:59.000Z

    Currently High Concentration Photovoltaic (HCPV) terrestrial modules are based on the combination of optic elements that concentrate the sunlight into much smaller GaAs space cells to produce electricity. GaAs cell technology has been well developed for space applications during the last two decades, but the use of GaAs cells under concentrated sunlight in terrestrial applications leaves unanswered questions about performance, durability and reliability. The work to be performed under this CRADA will set the basis for the design of high-performance, durable and reliable HCPV terrestrial modules that will bring down electricity production costs in the next five years.

  3. Innovative Composite Wall System for Sheathing Masonry Walls

    SciTech Connect (OSTI)

    Wendt, Robert L. [Oak Ridge National Lab., TN (United States); Cavallo, James [Argonne National Lab., IL (United States)

    1997-09-25T23:59:59.000Z

    Existing Housing - Much of the older multifamily housing stock in the United States includes units in structures with uninsulated masonry walls. Included in this stock are two- and three-story walk-up apartments, larger apartment complexes, and public housing (both high- rise and townhouse). This older multifamily housing has seen years of heavy use that may have left the plaster wall marred or damaged. Long- term building settlement or movement may have cracked the plaster, sometimes severely. Moisture from invented kitchens and baths may have caused condensation on uninsulated exterior walls. At best this condensation has left stains on the paint or wallpaper. At worst it has supported mold and mildew growth, fouling the air and creating unhealthy living conditions. Deteriorating plaster and flaking paint also result from wet walls. The presence of flaking, lead-based paint in older (pre-1978) housing is a major public health concern. Children can suffer permanent mental handicaps and psychological disorders if they are subjected to elevated levels of lead, while adults can suffer hypertension and other maladies. Studies have found that, in some urban communities with older housing stocks, over 35% of children tested have elevated blood lead levels (Hastings, et al.: 1997). Nationally, nearly 22% of black, non-hispanic children living in pre-1946 housing were found to have elevated levels of lead in their blood (MWWR Article: February 21,1997). The deterioration of many of these walls is to the point that lead can freely enter the living space.

  4. Silesia Dryvit

    SciTech Connect (OSTI)

    Presz, K.

    1995-12-31T23:59:59.000Z

    MT International, as a manufacturer and distributor for of US company named Dryvit Systems is focused on weatherization techniques as well as on facade and external wall finishing. The materials manufactured by Dryvit for building and construction purposes (plaster masses, building binders, insulating materials, reinforced fabric, etc.) are used at many sites. The consistent and well-selected composition of these materials guarantees highest quality of facade finishing in building structures of any type. The first implementation of Dryvit system in Warsaw was completed in 1974 and it remains the first exampled of professionally weatherized building in Poland. Different versions of Dryvit system have been elaborated for various plaster base types. Consequently the assembling procedure differs, too. The main classification includes methods used directly on-site by a specialized contractor as well as prefabrication systems in which the ready-made elements prefabricated in a central plant or in a moveable unit are mounted on the walls. Distribution of materials and systems is based upon a network of branch offices and plaster mass mixter plants located in Warsaw, Szczecin, Lublin, Gdansk and Zabrze.

  5. European PVSECE Glasgow, Scotland 2000 III-V SPACE SOLAR CELLS ON Si SUBSTRATES USING GRADED GeSi BUFFERS

    E-Print Network [OSTI]

    As directly grown on Si, rendering the GaAs useless as a photovoltaic material. Nevertheless, many groups have, this dislocation density has still limited the minority carrier lifetimes obtained to ~ 1-3 ns, even after hydrogen

  6. ambrym island vanuatu: Topics by E-print Network

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

    subpicosecond carrier dynamics C. Kadowa) Materials; accepted for publication 5 October 1999 We report the growth of self-assembled ErAs islands embedded in GaAs by molecular beam...

  7. aphae island shinan-gun: Topics by E-print Network

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

    subpicosecond carrier dynamics C. Kadowa) Materials; accepted for publication 5 October 1999 We report the growth of self-assembled ErAs islands embedded in GaAs by molecular beam...

  8. aphaedo island shinan-gun: Topics by E-print Network

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

    subpicosecond carrier dynamics C. Kadowa) Materials; accepted for publication 5 October 1999 We report the growth of self-assembled ErAs islands embedded in GaAs by molecular beam...

  9. anticosti island laurentia: Topics by E-print Network

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

    subpicosecond carrier dynamics C. Kadowa) Materials; accepted for publication 5 October 1999 We report the growth of self-assembled ErAs islands embedded in GaAs by molecular beam...

  10. aegna island tallinn: Topics by E-print Network

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

    subpicosecond carrier dynamics C. Kadowa) Materials; accepted for publication 5 October 1999 We report the growth of self-assembled ErAs islands embedded in GaAs by molecular beam...

  11. Fabrication of Molecular Devices

    E-Print Network [OSTI]

    Walton, Katherine

    2011-08-04T23:59:59.000Z

    This project focuses on the synthesis and attachment of metal nanoparticles to Au and GaAs surfaces using a combination of chemical self-assembly and scanned probe lithography. In this project self-assembled monolayers (SAMs) of alkanethiols...

  12. Monolithic heteroepitaxial integration of III-V semiconductor lasers on Si substrates

    E-Print Network [OSTI]

    Groenert, Michael

    2002-01-01T23:59:59.000Z

    Monolithic optoelectronic integration on silicon-based integrated circuits has to date been limited to date by the large material differences between silicon (Si) and the direct-bandgap GaAs compounds from which optoelectronic ...

  13. In-situ deposition of high-k dielectrics on III-V compound semiconductor in MOCVD system

    E-Print Network [OSTI]

    Cheng, Cheng-Wei, Ph.D. Massachusetts Institute of Technology

    2010-01-01T23:59:59.000Z

    In situ deposition of high-k materials to passivate the GaAs in metal organic chemical vapor deposition (MOCVD) system was well demonstrated. Both atomic layer deposition (ALD) and chemical vapor deposition (CVD) methods ...

  14. Investigation of the GaN-on-GaAs interface for vertical power device applications

    SciTech Connect (OSTI)

    Mreke, Janina, E-mail: janina.moereke@bristol.ac.uk; Uren, Michael J.; Kuball, Martin [H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Novikov, Sergei V.; Foxon, C. Thomas [Department of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hosseini Vajargah, Shahrzad; Wallis, David J.; Humphreys, Colin J. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Haigh, Sarah J. [Super STEM Laboratory, STFC Daresbury Campus, Keckwick Lane, Daresbury WA4 4AD (United Kingdom); School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Al-Khalidi, Abdullah; Wasige, Edward; Thayne, Iain [School of Engineering, University of Glasgow, Rankine Bldg, Oakfield Avenue, Glasgow G12 8LT (United Kingdom)

    2014-07-07T23:59:59.000Z

    GaN layers were grown onto (111) GaAs by molecular beam epitaxy. Minimal band offset between the conduction bands for GaN and GaAs materials has been suggested in the literature raising the possibility of using GaN-on-GaAs for vertical power device applications. I-V and C-V measurements of the GaN/GaAs heterostructures however yielded a rectifying junction, even when both sides of the junction were heavily doped with an n-type dopant. Transmission electron microscopy analysis further confirmed the challenge in creating a GaN/GaAs Ohmic interface by showing a large density of dislocations in the GaN layer and suggesting roughening of the GaN/GaAs interface due to etching of the GaAs by the nitrogen plasma, diffusion of nitrogen or melting of Ga into the GaAs substrate.

  15. Exchange Control of Nuclear Spin Diffusion in a Double Quantum Dot

    E-Print Network [OSTI]

    Reilly, D. J.

    The influence of gate-controlled two-electron exchange on the relaxation of nuclear polarization in small ensembles (N?10[superscript 6]) of nuclear spins is examined in a GaAs double quantum dot system. Waiting in the ...

  16. E-Print Network 3.0 - affecting ex-situ aqueous Sample Search...

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

    Heather C.- Department of Chemistry, Ohio State University Collection: Chemistry 76 HfO2 gate dielectric on ,,NH4...2S passivated ,,100... GaAs grown by atomic layer...

  17. Second-order susceptibility from a tight-binding Hamiltonian

    E-Print Network [OSTI]

    Dumitrica, T.; Graves, JS; Allen, Roland E.

    1998-01-01T23:59:59.000Z

    to calculate the energy dependence of X-(2)(omega) for GaAs. The results are in agreement with previous calculations and with available experimental data. [S0163-1829(98)01848-7]....

  18. E-Print Network 3.0 - algaas mid infrared Sample Search Results

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

    processes in the mid-infrared. Bahram Jalali WILEY 20 Macmillan... Flexible optoelectronics PHOTOVOLTAICS of AlGaAs deposited on a GaAs wafer. The clever part of the scheme...

  19. U.S. GEOLOGICAL SURVEY--MINERALS INFORMATION 1 By Deborah A. Kramer

    E-Print Network [OSTI]

    ). to produce optoelectronic devices and integrated circuits for Increased demand for GaAs resulted in several U. Consumption Optoelectronic devices continued to be the largest end use for gallium, with 59% of total

  20. GaN quantum dot superlattices grown by molecular beam epitaxy at high temperature

    E-Print Network [OSTI]

    P-based optoelectronic devices with Si microelectronic devices. This method uses a Au-Ge eutectic alloy as the bonding. The realization of integrafion of GaAs- and InP-based optoelectronic devices with Si microelectronic components

  1. RESEARCH/RESEARCHERS 4 MRS BULLETIN VOLUME 34 JANUARY 2009 www.mrs.org/bulletin

    E-Print Network [OSTI]

    Zhang, Xin

    wallpaper-Group Metamaterials Display Multiple Terahertz Resonances Metamaterials--artificial structures. A standard lift-off process was used to fabricate the metama- terials onto a semi-insulating (SI) GaAs wafer

  2. Substrate engineering for monolithic integration of III-V semiconductors with Si CMOS technology

    E-Print Network [OSTI]

    Dohrman, Carl Lawrence

    2008-01-01T23:59:59.000Z

    Ge virtual substrates, fabricated using Si1-xGex-.Ge, compositionally graded buffers, enable the epitaxial growth of device-quality GaAs on Si substrates, but monolithic integration of III-V semiconductors with Si CMOS ...

  3. Structure and electrical characterization of gallium arsenide nanowires with different V/III ratio growth parameters

    SciTech Connect (OSTI)

    Muhammad, R.; Ahamad, R. [Sustainability Research Alliance, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Ibrahim, Z.; Othaman, Z. [Physic Department, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

    2014-03-05T23:59:59.000Z

    Gallium arsenide (GaAs) nanowires were grown vertically on GaAs(111)B substrate by gold-assisted using metal-organic chemical vapour deposition. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and conductivity atomic force microscopy (CAFM) analysis were carried out to investigate the effects of V/III ratio on structural properties and current-voltage changes in the wires. Results show that GaAs NWs grow preferably in the wurtzite crystal structure than zinc blende crystal structure with increasing V/III ratio. Additionally, CAFM studies have revealed that zincblende nanowires indicate ohmic characteristic compared to oscillation current occurred for wurtzite structures. The GaAs NWs with high quality structures are needed in solar cells technology for trapping energy that directly converts of sunlight into electricity with maximum capacity.

  4. MANUSCRIPT PREPARATION TEMPLATE FOR THE 35TH IEEE PHOTOVOLTAIC...

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

    FORM FACTOR GaAs SOLAR CELL Cruz-Campa, J. L. 1 ; Nielson, G. N. 1 ; Okandan, M. 1 ; Wanlass, M. W. 2 ; Sanchez, C. A. 1 ; Resnick. P. J. 1 ; Clews, P. J. 1 ; Pluym, T. 1 ;...

  5. Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module

    SciTech Connect (OSTI)

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Cowley, S.; Kayes, B.; Kurtz, S.

    2013-06-01T23:59:59.000Z

    We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

  6. Exploring Self-Assembly and Photomechanical Switching Properties of Molecules at Surfaces

    E-Print Network [OSTI]

    Cho, Jongweon

    2010-01-01T23:59:59.000Z

    11.4 Self-Assembly Properties . . . . . . . . . . . . . 11.512.2 Self-Assembly of TTB-AB on GaAs(110) . . . . . . . 12.3at Surfaces 4 Self-Assembly Properties of Azobenzene on Au(

  7. Organometallic vapor-phase homoepitaxy of gallium arsenide assisted by a downstream hydrogen afterglow plasma in the growth region

    E-Print Network [OSTI]

    Collins, George J.

    of the trimeth- ylgallium (TMGa) for homoepitaxial GaAs. They found in direct comparison of the pure thermal-insulating) substrate is loaded into the depo- sition reactor of Fig. 1 without any chemical degreasing or polishing

  8. The Effect of Offcut Angle on Electrical Conductivity of Direct Wafer-Bonded n-GaAs/n-GaAs Structures for Wafer-Bonded Tandem Solar Cells

    E-Print Network [OSTI]

    Yeung, King Wah Sunny

    2012-01-01T23:59:59.000Z

    Efficiency of p?n Junction Solar Cells, J. Appl. Phys. 32,Inverted Triple- Junction Solar Cell with Two Independentlyof Thin-Film GaAs Solar Cells on Si Substrates, J. Appl.

  9. Low-dimensional carbon nanotube and graphene devices

    E-Print Network [OSTI]

    Scard, Philip

    2010-10-12T23:59:59.000Z

    -jet printing of nanotubes directly onto GaAs. Although only one atom thick, graphene is macroscopic in area and must be patterned to confine conduction; room temperature transistor behaviour requires graphene ribbons only a few nanometres wide. This work...

  10. E-Print Network 3.0 - ambichiral electro-optic structure Sample...

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

    freely propagating continuous-wave terahertz radiation using electro-optic detection. The terahertz... -temperature-grown GaAs. This radiation is detected using the electro-optic...

  11. Nanopillar Photovoltaics: Photon Management and Junction Engineering for Next-Generation Solar Cells

    E-Print Network [OSTI]

    Mariani, Giacomo

    2013-01-01T23:59:59.000Z

    S. Heterojunction photovoltaics using GaAs nanowires andC. M. Single nanowire photovoltaics, Chem. Soc. Rev. 38, 16-nanopillar-array photovoltaics on low-cost and flexible

  12. Technical Session II Talks | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    .pdf file (6.2MB) GaAs Detector (Durbin) .pdf file (450KB) Advanced Neutron Detectors (Smith) .pdf file (818KB) Neutron Imaging System (Bingham) .pdf file (1.1MB) SR Advanced...

  13. Theoretical analysis of strain and strain decay in InAs/GaAs,,001... multilayer quantum dot growth

    E-Print Network [OSTI]

    As or is assumed to change linearly from 50% at the bottom to 100% at the top. The exact QD dimensions GaAs spacer layers typically 20 nm . In these cases not only the effects of In migration

  14. anisotropic magnetoresistive sensor: Topics by E-print Network

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

    Israel (Received 14 March 1996) A periodic array of cylindrical voids, embedded in a thin film of n-doped GaAs, displays a pronounced anisotropy of the classical...

  15. Eighth Annual Student Research

    E-Print Network [OSTI]

    Southern California, University of

    Dongseok Kang Carbon-doped GaAs single junction solar cells grown in multilayer epitaxial assemblies (with and poster session 2:30 PM awards ceremony #12;Posters Graduate student posters Laura Bradley Encapsulation

  16. 2008 Minerals Yearbook U.S. Department of the Interior

    E-Print Network [OSTI]

    , electronic warfare, and phased array radar. The ONR program's objectives were to extend the use of the high voltage Gaas pseudomorphic high electron mobility transistor (pHmET) technology to higher frequencies

  17. VOLUME 84, NUMBER 15 P H Y S I C A L R E V I E W L E T T E R S 10 APRIL 2000 Coherent Control of Absorption and Polarization Decay in a GaAs Quantum Well

    E-Print Network [OSTI]

    Hohng, Sung Chul

    , Renthof 5, D-35032 Marburg, Germany (Received 1 July 1999) Two phase-locked pulses are used to coherently of transform-limited pulses with a pulse duration of 150 fs. We produce two phase-locked collinear pulses excite excitonic polarizations. It is shown that the second pulse can either be strongly amplified

  18. Effect of MnAs/GaAs(001) film accommodations on the phase-transition temperature

    SciTech Connect (OSTI)

    Iikawa, F.; Brasil, M.J.S.P.; Couto, O.D.D.; Adriano, C.; Giles, C.; Daeweritz, L. [Instituto de Fisica 'Gleb Wataghin', UNICAMP, Campinas-SP, C.P. 6165, 13083-970 (Brazil); Instituto de Fisica 'Gleb Wataghin', UNICAMP, Campinas-SP, C.P. 6165, 13083-970, Brazil and Laboratorio Nacional de Luz Sincrotron, CP-6192, 13084-971 Campinas-SP (Brazil); Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2004-09-20T23:59:59.000Z

    The phase-transition temperature of MnAs epitaxial films grown by molecular-beam epitaxy on GaAs(001) with different crystalline accommodations was studied by specular and grazing incidence x-ray diffraction. The transition temperature of MnAs films with tilted hexagonal c-axis orientations with respect to the GaAs substrate is higher than the most investigated nontilted films and reaches a value above room temperature, which is more suitable for device applications.

  19. Monitoring interfacial dynamics by pulsed laser techniques

    SciTech Connect (OSTI)

    Richmond, G.L.

    1991-01-01T23:59:59.000Z

    Goal is to develop new optical methods for the study of dynamic processes at the electrode/electrolyte interface. In the past year, optical second harmonic generation was used for time resolved measurements of thallium electrodeposition on Cu(111). Other studies included the study of the photochemistry involved in a GaAs surface treatment known as photowashing, and the study of picosecond time resolved luminescence decays from GaAs in electrochemical environments (power dependent effects). 4 figs. (DLC)

  20. Monitoring interfacial dynamics by pulsed laser techniques. Third yearly progress report

    SciTech Connect (OSTI)

    Richmond, G.L.

    1991-12-31T23:59:59.000Z

    Goal is to develop new optical methods for the study of dynamic processes at the electrode/electrolyte interface. In the past year, optical second harmonic generation was used for time resolved measurements of thallium electrodeposition on Cu(111). Other studies included the study of the photochemistry involved in a GaAs surface treatment known as photowashing, and the study of picosecond time resolved luminescence decays from GaAs in electrochemical environments (power dependent effects). 4 figs. (DLC)

  1. New GaInP/GaAs/GaInAs, Triple-Bandgap, Tandem Solar Cell for High-Efficiency Terrestrial Concentrator Systems

    SciTech Connect (OSTI)

    Kurtz, S.; Wanlass, M.; Kramer, C.; Young, M.; Geisz, J.; Ward, S.; Duda, A.; Moriarty, T.; Carapella, J.; Ahrenkiel, P.; Emery. K.; Jones, K.; Romero, M.; Kibbler, A.; Olson, J.; Friedman, D.; McMahon, W.; Ptak, A.

    2005-11-01T23:59:59.000Z

    GaInP/GaAs/GaInAs three-junction cells are grown in an inverted configuration on GaAs, allowing high quality growth of the lattice matched GaInP and GaAs layers before a grade is used for the 1-eV GaInAs layer. Using this approach an efficiency of 37.9% was demonstrated.

  2. Journal of Electronic Materials, Vol. 17, No. 5, 1988 Effect of Iso-Electronic

    E-Print Network [OSTI]

    Woodall, Jerry M.

    Journal of Electronic Materials, Vol. 17, No. 5, 1988 Effect of Iso-Electronic GaAs Dopants that addition of either one of these two iso-electronic dopants has a similar effect on the solid stoichiometry it is also shown that the addition of the iso-electronic dopants A1 or P to GaAs would not result in the same

  3. Fabrication and characterization of modulation-doped-field-effect-transistors with antidot-patterned passivation layers

    E-Print Network [OSTI]

    Hwang, Sung Woo

    layer with 1 1017 cm 3 Si doping, 50 nm Al0.3Ga0.7As spacer with 1 1018 cm 3 Si doping, 15 nm undoped Al0.3Ga0.7As spacer, 500 nm un- doped GaAs channel layer, 20 periods of 5/5 nm GaAs/ Al. For the demonstration of the internal gate patterning, two types of MODFET's with the same overall gate dimensions

  4. Experimental study of reactions between ozone and building products M. Nicolas, O. Ramalho, F. Maupetit*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ozone and building products and document their potential impact on indoor air quality. PreliminaryExperimental study of reactions between ozone and building products M. Nicolas, O. Ramalho, F experiments were conducted on four building products: two carpets, a gypsum board and a pine wood board

  5. Non-Traditional Soil Additives: Can They Improve Crop Production?

    E-Print Network [OSTI]

    Mukhtar, Saqib

    residues. 2) Mined mineral deposits that are unprocessed except for grinding. Again, the composi- tion residues, livestock manures and sewage sludge. Non- traditional soil conditioners include both organic potassium), and gypsum or sand. 3) Mined humates or humic acids. These are prehistoric organic deposits

  6. Icarus 196 (2008) 422432 www.elsevier.com/locate/icarus

    E-Print Network [OSTI]

    Bourke, Mary C.

    . Introduction The most extensive sand dune deposit on Mars encircles the north-polar residual water­ice deposit, decreasing in concentration downwind, suggesting deposition via an ae- olian dust plume. Alternate sources of gypsum signature de- tected in the dunefield are thought to be from the polar-layered deposits' basal

  7. Soil and Water Science Department University of Florida RECYLCING OF GUYPSUM DRYWALL IN FLORIDA

    E-Print Network [OSTI]

    Ma, Lena

    Soil and Water Science Department University of Florida RECYLCING OF GUYPSUM DRYWALL IN FLORIDA of landfills in Florida, it is more cost- effective to reuse them. However, there are some concerns the recycling of three important solid wastes in Florida, i.e. #1 cement kiln dust (CKD) and #16 gypsum drywalls

  8. Iron and Steel Phosphate Rock

    E-Print Network [OSTI]

    Torgersen, Christian

    Phosphate Rock Platinum Potash Pumice Quartz Crystal Rare Earths Rhenium Rubidium Salt Sand and Gravel Graphite Peat Sulfur Beryllium Gypsum Perlite Talc Bismuth Hafnium Phosphate Rock Tantalum Boron Helium on the USGS--the Federal source for science about the Earth, its natural and living resources, natural hazards

  9. Energy and Buildings 70 (2014) 135144 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    North Texas, University of

    s t r a c t We have added expanded vermiculite and polypropylene fibers with low thermal conductivity were improved by the addition of expanded silica gel granules introduced into the gypsum [8]. Also://www.unt.edu/LAPOM (W. Brostow). 1 Tel.: +1 940 565 4358; fax: +1 940 565 4824. fiber, polyamide fiber, polyester fiber

  10. Optical properties of the Dead Sea Emmanuel Boss,1

    E-Print Network [OSTI]

    Boss, Emmanuel S.

    has been precipitating salts, in particular NaCl [Anati, 1993; Stiller et al., 1997]. Due to selective, 1983; Anati, 1993; Gavrieli, 1997; Stiller et al., 1997]. In addition, Gavrieli [1997] (and references therein) and Stiller et al. [1997] reported observations of suspended crystals of gypsum and aragonite

  11. 2001 by the Arizona Board of Regents on behalf of the University of Arizona Near East Chronology: Archaeology and Environment. RADIOCARBON, Vol 43, Nr 3, 2001, p 11791189

    E-Print Network [OSTI]

    Yehouda, Enzel

    with respect to salt and gypsum (Neev and Emery 1967; Stiller et al. 1997). The water has a wide range of inorganic radiocarbon composition (Stiller et al. 1988; Talma et al. 1997). Runoff water often formed a less have also occurred naturally in the past (Stiller and Chung 1984) inducing changes in the bottom lake

  12. PORTSMOUTH HARBOR AND PISCATAQUA RIVER, NH & ME NAVIGATION IMPROVEMENT PROJECT

    E-Print Network [OSTI]

    US Army Corps of Engineers

    on the terminals located above Interstate 95. Cargoes include petroleum fuels, cement, gypsum, and liquid propane. The study evaluated project benefits based on reduction in transportation costs generated from a shift. The Recommended Plan will generate significant economic benefits for the nation, and is the National Economic

  13. Three-dimensional fracture and fragmentation of artificial kidney stones This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Ortiz, Michael

    Three-dimensional fracture and fragmentation of artificial kidney stones This article has been IOPscience #12;Three-dimensional fracture and fragmentation of artificial kidney stones Alejandro Mota1 Laboratory Livermore, CA 94550, USA July 25, 2006 Abstract The brittle fracture of a gypsum cylinder, which

  14. Burgeoning Biomass: Creating Efficient and Sustainable Forest Biomass Supply Chains in the Rockies

    E-Print Network [OSTI]

    Mountain forests. Most active forest management activities on public and private land, such as thinning be converted into fuel, heat and electricity. Eagle Valley Clean Energy in Gypsum, Colorado, is one such facility, and is Colorado's first dedicated biomass power plant, producing 11.5 megawatts of electricity

  15. Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass

    E-Print Network [OSTI]

    Najjar, Namir Fouad

    1995-01-01T23:59:59.000Z

    accumulation but exchangeable Na also increased as a function of years of irrigation. The multiple regression equation: SARE =-5.16 + 0.53 SARiw + 4.04 In (yr) (R2 = 0.86) best predicted SARE to a depth of 30 cm. This study also compared gypsum, a common...

  16. Harmful algal bloom species and phosphate-processing effluent: Field and laboratory studies

    E-Print Network [OSTI]

    Meyers, Steven D.

    Harbor in southern Tampa Bay (Fig. 1). The State of Florida was then left to dispose of more than 1). Instabilities in the aging phospho- gypsum stacks of the Piney Point phosphate plant, along with potential an emergency permit to the FDEP allowing transport by barge of wastewater to an area greater than 74 km

  17. Particle Size Distribution of Gypseous Samples

    E-Print Network [OSTI]

    Arnett, Morgan P.

    2010-01-16T23:59:59.000Z

    to conditions in the field. In order to understand the true characterization of the soil and the gypsum particles, the entire soil sample should be analyzed. Four different approaches to the BaCl2 method presented in the literature (Hesse, 1976, Matar...

  18. Carbon doping of III-V compound semiconductors

    SciTech Connect (OSTI)

    Moll, A.J.

    1994-09-01T23:59:59.000Z

    Focus of the study is C acceptor doping of GaAs, since C diffusion coefficient is at least one order of magnitude lower than that of other common p-type dopants in GaAs. C ion implantation results in a concentration of free holes in the valence band < 10% of that of the implanted C atoms for doses > 10{sup 14}/cm{sup 2}. Rutherford backscattering, electrical measurements, Raman spectroscopy, and Fourier transform infrared spectroscopy were amonth the techniques used. Ga co-implantation increased the C activation in two steps: first, the additional radiation damage creates vacant As sites that the implanted C can occupy, and second, it maintains the stoichiometry of the implanted layer, reducing the number of compensating native defects. In InP, the behavior of C was different from that in GaAs. C acts as n-type dopant in the In site; however, its incorporation by implantation was difficult to control; experiments using P co-implants were inconsistent. The lattice position of inactive C in GaAs in implanted and epitaxial layers is discussed; evidence for formation of C precipitates in GaAs and InP was found. Correlation of the results with literature on C doping in III-V semiconductors led to a phenomenological description of C in III-V compounds (particularly GaAs): The behavior of C is controlled by the chemical nature of C and the instrinsic Fermi level stabilization energy of the material.

  19. Thermal stability of certain hydrated phases in systems made using portland cement. Final report

    SciTech Connect (OSTI)

    Buck, A.D.; Burkes, J.P.; Poole, T.S.

    1985-08-01T23:59:59.000Z

    As part of the study of hydraulic-cement system for use in possible underground isolation of nuclear wastes, this study was made to determine the temperature stability of ettringite and chloroaluminate. Either or both of these phases may be expected in a hydraulic cement system depending on the presence of salt (NaCl). The study of ettringite was made using 15 mixtures that contained portland cement, plaster, 2 levels of water, and in some mixtures, 1 of 6 pozzolans (3 fly ashes, 1 slag, a silica fume, a natural pozzolan), plus a 16th mixture with anhydrous sodium sulfate replacing plaster (CaSO4 . 1/2H20). Specimens were made and stored at 23, 50, and 75 C or 23, 75, and 100 C (all four temperatures in one case) for periodic examination by x-ray diffraction for phase compositiion and ettringite stability, and testing for compressive strength and restrained expansion. A more limited study of the stability of chloroaluminate was made along the same lines using fewer mixtures, salt instead of plaster, and higher temperatures plus some pressure. It was found that while some ettringette was decomposed at 75 C, depending on the composition of the mixture, all ettringite was undetectable by x-ray diffraction at 100 C, usually within a few days. The evidence indicates that the ettringite became amorphous and no significant test phases formed in its place. Since there was no corresponding loss in strength or reduction in volume, this loss of ettringite crystallinity was considered to be damaging. Based on much more limited data, chloroaluminate was found to decompose between 130 C at 25 psi and 170 C at 100 psi; no significant phases replaced it.

  20. Children and lead: new findings and concerns

    SciTech Connect (OSTI)

    Lin-Fu, J.S.

    1982-09-02T23:59:59.000Z

    An editorial dealing with lead in the environment and its health risks to children is presented. Young children are particularly vulnerable to lead exposure. Through hand-to-mouth activities, such as thumb sucking, nail biting, or eating with dirty hands, lead in house dust and garden soil readily enters their bodies. Children with pica are exposed to more lead because they eat such items as paint chips, broken plaster, and dirt. Moreover, intestinal lead absorption is greater in children than in adults. The author recommends a concerted effort to reduce undue lead absorption in children. (JMT)