Sample records for 3-dimensional converted shear

  1. Conducting a 3D Converted Shear Wave Project to Reduce Exploration...

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

    The primary objective of this project is to conduct a 3C 3D (converted shear wave) seismic survey to reduce exploration risk by characterizing fault and fracture geometrics at...

  2. Conducting a 3D Converted Shear Wave Project to Reduce Exploration Risk at Wister, CA

    Broader source: Energy.gov [DOE]

    DOE Geothermal Technologies Peer Review 2010 - Presentation. The primary objective of this project is to conduct a 3C 3D (converted shear wave) seismic survey to reduce exploration risk by characterizing fault and fracture geometrics at Wister, CA.The intent of the proposed program is to use a 3D seismic survey with converted shear waves combined with other available data to site and drill production wells at Wister, a blind geothermal resource.

  3. Beam converter

    DOE Patents [OSTI]

    Poulsen, Peter

    2003-05-06T23:59:59.000Z

    A converter and method for converting electron energy to irradiative energy comprising foam and/or foil. Foam and foil optionally comprise a high-Z material, such as, but not limited to, tantalum.

  4. Performance Analysis of 3-Dimensional Turbo Codes

    E-Print Network [OSTI]

    Rosnes, Eirik

    2011-01-01T23:59:59.000Z

    In this work, we consider the minimum distance properties and convergence thresholds of 3-dimensional turbo codes (3D-TCs), recently introduced by Berrou et al.. Here, we consider binary 3D-TCs while the original work of Berrou et al. considered double-binary codes. In the first part of the paper, the minimum distance properties are analyzed from an ensemble perspective, both in the finite-length regime and in the asymptotic case of large block lengths. In particular, we analyze the asymptotic weight distribution of 3D-TCs and show numerically that their typical minimum distance dmin may, depending on the specific parameters, asymptotically grow linearly with the block length, i.e., the 3D-TC ensemble is asymptotically good for some parameters. In the second part of the paper, we derive some useful upper bounds on the dmin when using quadratic permutation polynomial (QPP) interleavers with a quadratic inverse. Furthermore, we give examples of interleaver lengths where an upper bound appears to be tight. The b...

  5. Thermionic converter

    DOE Patents [OSTI]

    Fitzpatrick, G.O.

    1987-05-19T23:59:59.000Z

    A thermionic converter is set forth which includes an envelope having an electron collector structure attached adjacent to a wall. An electron emitter structure is positioned adjacent the collector structure and spaced apart from opposite wall. The emitter and collector structures are in a common chamber. The emitter structure is heated substantially only by thermal radiation. Very small interelectrode gaps can be maintained utilizing the thermionic converter whereby increased efficiency results. 10 figs.

  6. Light field applications to 3-dimensional surface imaging

    E-Print Network [OSTI]

    Hong, Wenxian

    2009-01-01T23:59:59.000Z

    The structure of light around a scene may be contained in a 4-dimensional array known as a light field. This thesis describes methods for acquiring and manipulating light fields for applications in 3-dimensional imaging. ...

  7. Thermionic converter

    DOE Patents [OSTI]

    Fitzpatrick, Gary O. (Livermore, CA)

    1987-05-19T23:59:59.000Z

    A thermionic converter (10) is set forth which includes an envelope (12) having an electron collector structure (22) attached adjacent to a wall (16). An electron emitter structure (24) is positioned adjacent the collector structure (22) and spaced apart from opposite wall (14). The emitter (24) and collector (22) structures are in a common chamber (20). The emitter structure (24) is heated substantially only by thermal radiation. Very small interelectrode gaps (28) can be maintained utilizing the thermionic converter (10) whereby increased efficiency results.

  8. Thermionic converter

    SciTech Connect (OSTI)

    Fitzpatrick, G.O.

    1987-05-19T23:59:59.000Z

    A thermionic converter is described comprising: an envelope having first and second walls spaced apart from one another. The envelope defines an enclosed chamber; an electron collector structure attached adjacent to the second wall; an electron emitter structure, located adjacent the collector structure and between the collector structure and the first wall. At least a respective one of the collector structure and the emitter structure comprise elements, each of the elements along with a respective other of the collector structure and the emitter structure defining interelectrode gaps at least when the emitter structure is above a selected temperature. The emitter structure is spaced a distance away from the first wall and is positioned to receive substantially only thermal radiation.

  9. Combustion converter design evolution

    SciTech Connect (OSTI)

    Goodale, D.B.; Miskolczy, G.

    1984-08-01T23:59:59.000Z

    The early thermionic converters used hemispherical one-inch-diameter hot shells. They were extensively tested in a natural gas, high-temperature furnace. A converter was life tested for 12,500 hours at emitter temperatures above 1700 K. Two-inch diameter converters with both hemispherical and torispherical shapes were developed next. These converters have been tested in both natural gas-, oil-, and coal-oil slurry-fired environments. A prototype converter for cogeneration applications was also developed using this emitter configuration. A six converter module of cogeneration converters has been constructed.

  10. Full bridge converter Transformers and isolated converters

    E-Print Network [OSTI]

    Knobloch,Jürgen

    Full bridge converter Transformers and isolated converters Most DC power supplies have the following requirements: 1. Regulated output voltage Solved by a large capacitor at the output, and feedback control. 2. High power factor PFC - discussed previously. 3. Isolation 4. Multiple outputs Isolated

  11. Heat pulse propagation in chaotic 3-dimensional magnetic fields

    E-Print Network [OSTI]

    D. del-Castillo-Negrete; D. Blazevski

    2014-09-10T23:59:59.000Z

    Heat pulse propagation in $3$-D chaotic magnetic fields is studied by solving the parallel heat transport equation using a Lagrangian-Green's function (LG) method. The LG method provides an efficient and accurate technique that circumvents limitations of finite elements and finite difference methods. The main two problems addressed are: (i) The dependence of the radial transport on the magnetic field stochasticity (controlled by the amplitude of the perturbation, $\\epsilon$); and (ii) The role of reversed shear configurations on pulse propagation. In all the cases considered there are no magnetic flux surfaces. However, radial transport is observed to depend strongly on $\\epsilon$ due to the presence of high-order magnetic islands and Cantori that act as quasi-transport barriers that preclude the radial penetration of heat pulses within physically relevant time scale. The dependence of the magnetic field connection length, $\\ell_B$, on $\\epsilon$ is studied in detail. The decay rate of the temperature maximum, $\\langle T \\rangle_{max}(t)$, the time delay of the temperature response as function of the radius, $\\tau$, and the radial heat flux $\\langle {{\\bf q}\\cdot {\\hat e}_\\psi} \\rangle$, are also studied as functions of the magnetic field stochasticity and $\\ell_B$. In all cases, the scaling of $\\langle T \\rangle_{max}$ with $t$ transitions from sub-diffusive, $\\langle T \\rangle_{max} \\sim t^{-1/4}$, at short times ($\\chi_\\parallel t 10^5$). A strong dependence on $\\epsilon$ is also observed on $\\tau$ and $\\langle {{\\bf q}\\cdot {\\hat e}_\\psi} \\rangle$. The radial propagation of pulses in fully chaotic fields considerably slows down in the shear reversal region and, as a result, $\\tau$, in reversed shear configurations is an order of magnitude longer than the one in monotonic $q$-profiles.

  12. Pseudocodewords of Linear Programming Decoding of 3-Dimensional Turbo Codes

    E-Print Network [OSTI]

    Rosnes, Eirik; Amat, Alexandre Graell i

    2011-01-01T23:59:59.000Z

    In this work, we consider pseudocodewords of (relaxed) linear programming (LP) decoding of 3-dimensional turbo codes (3D-TCs), recently introduced by Berrou et al.. Here, we consider binary 3D-TCs while the original work of Berrou et al. considered double-binary codes. We present a relaxed LP decoder for 3D-TCs, which is an adaptation of the relaxed LP decoder for conventional turbo codes proposed by Feldman in his thesis. The vertices of this relaxed polytope are the pseudocodewords. We show that the support set of any pseudocodeword is a stopping set of iterative decoding of 3D-TCs using maximum a posteriori constituent decoders on the binary erasure channel. Furthermore, we present a numerical study of small block length 3D-TCs, which shows that typically the minimum pseudoweight (on the additive white Gaussian noise (AWGN) channel) is smaller than both the minimum distance and the stopping distance. In particular, we performed an exhaustive search over all interleaver pairs in the 3D-TC based on quadratic...

  13. 3-dimensional imaging system using crystal diffraction lenses

    DOE Patents [OSTI]

    Smither, R.K.

    1999-02-09T23:59:59.000Z

    A device for imaging a plurality of sources of x-ray and gamma-ray radiation is provided. Diffracting crystals are used for focusing the radiation and directing the radiation to a detector which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for a method for imaging x-ray and gamma radiation by supplying a plurality of sources of radiation; focusing the radiation onto a detector; analyzing the focused radiation to collect data as to the type and location of the radiation; and producing an image using the data. 18 figs.

  14. 3-dimensional imaging system using crystal diffraction lenses

    DOE Patents [OSTI]

    Smither, Robert K. (Hinsdale, IL)

    1999-01-01T23:59:59.000Z

    A device for imaging a plurality of sources of x-ray and gamma-ray radiation is provided. Diffracting crystals are used for focussing the radiation and directing the radiation to a detector which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for a method for imaging x-ray and gamma radiation by supplying a plurality of sources of radiation; focussing the radiation onto a detector; analyzing the focused radiation to collect data as to the type and location of the radiation; and producing an image using the data.

  15. Interleaved power converter

    DOE Patents [OSTI]

    Zhu, Lizhi (Canton, MI)

    2007-11-13T23:59:59.000Z

    A power converter architecture interleaves full bridge converters to alleviate thermal management problems in high current applications, and may, for example, double the output power capability while reducing parts count and costs. For example, one phase of a three phase inverter is shared between two transformers, which provide power to a rectifier such as a current doubler rectifier to provide two full bridge DC/DC converters with three rather than four high voltage inverter legs.

  16. ITER convertible blanket evaluation

    SciTech Connect (OSTI)

    Wong, C.P.C.; Cheng, E.

    1995-09-01T23:59:59.000Z

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.

  17. 3-DIMENSIONAL GEOMECHANICAL MODELING OF A TIGHT GAS RESERVOIR, RULISON FIELD, PICEANCE BASIN, COLORADO

    E-Print Network [OSTI]

    3-DIMENSIONAL GEOMECHANICAL MODELING OF A TIGHT GAS RESERVOIR, RULISON FIELD, PICEANCE BASIN, COLORADO by Kurtis R. Wikel #12;ii #12;iii ABSTRACT An integrated 3-dimensional geomechanical model have used the predictive geomechanical model to compare production and effective stress change

  18. Universal thermochemical energy converter

    DOE Patents [OSTI]

    Labinov, Solomon Davidovich (Oak Ridge, TN); Sand, James R. (Oak Ridge, TN); Conklin, James C. (Knoxville, TN); VanCoevering, James (Oak Ridge, TN); Courville, George E. (Oak Ridge, TN)

    2001-01-01T23:59:59.000Z

    Disclosed are methods and apparatus for a thermochemical closed cycle employing a polyatomic, chemically active working fluid for converting heat energy into useful work.

  19. Microminiature thermionic converters

    DOE Patents [OSTI]

    King, Donald B. (Albuquerque, NM); Sadwick, Laurence P. (Salt Lake City, UT); Wernsman, Bernard R. (Clairton, PA)

    2001-09-25T23:59:59.000Z

    Microminiature thermionic converts (MTCs) having high energy-conversion efficiencies and variable operating temperatures. Methods of manufacturing those converters using semiconductor integrated circuit fabrication and micromachine manufacturing techniques are also disclosed. The MTCs of the invention incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. Existing prior art thermionic converter technology has energy conversion efficiencies ranging from 5-15%. The MTCs of the present invention have maximum efficiencies of just under 30%, and thousands of the devices can be fabricated at modest costs.

  20. A 3-dimensional analysis of sight distance on interchange ramps and connectors

    E-Print Network [OSTI]

    Sanchez, Eddie

    1992-01-01T23:59:59.000Z

    A 3-DIMENSIONAL ANALYSIS OF SIGHT DISTANCE ON INTERCHANGE RAMPS AND CONNECTORS A Thesis by EDDIE SANCHEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfdlment of the requiretnents for the degree of MASTER... OF SCIENCE August 1992 Major Subject: Civil Engineering A 3-DIMENSIONAL ANALYSIS OF SIGHT DISTANCE ON INTERCHANGE RAMPS AND CONNECTORS A Thesis by EDDIE SANCHEZ Approved as to style and content by: Raymond A. Krammes (Chair of Committee) N ' n J...

  1. New Technique for Developing a Proton Range Compensator With Use of a 3-Dimensional Printer

    SciTech Connect (OSTI)

    Ju, Sang Gyu, E-mail: sg.ju@samsung.com [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Min Kyu; Hong, Chae-Seon; Kim, Jin Sung; Han, Youngyih; Choi, Doo Ho [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Shin, Dongho; Lee, Se Byeong [Proton Therapy Center, National Cancer Center, Gyeonggi-do (Korea, Republic of)

    2014-02-01T23:59:59.000Z

    Purpose: A new system for manufacturing a proton range compensator (RC) was developed by using a 3-dimensional printer (3DP). The physical accuracy and dosimetric characteristics of the new RC manufactured by 3DP (RC{sub 3}DP) were compared with those of a conventional RC (RC{sub C}MM) manufactured by a computerized milling machine (CMM). Methods and Materials: An RC for brain tumor treatment with a scattered proton beam was calculated with a treatment planning system, and the resulting data were converted into a new format for 3DP using in-house software. The RC{sub 3}DP was printed with ultraviolet curable acrylic plastic, and an RC{sub C}MM was milled into polymethylmethacrylate using a CMM. The inner shape of both RCs was scanned by using a 3D scanner and compared with TPS data by applying composite analysis (CA; with 1-mm depth difference and 1 mm distance-to-agreement criteria) to verify their geometric accuracy. The position and distal penumbra of distal dose falloff at the central axis and field width of the dose profile at the midline depth of spread-out Bragg peak were measured for the 2 RCs to evaluate their dosimetric characteristics. Both RCs were imaged on a computed tomography scanner to evaluate uniformity of internal density. The manufacturing times for both RCs were compared to evaluate the production efficiency. Results: The pass rates for the CA test were 99.5% and 92.5% for RC{sub 3}DP and RC{sub C}MM, respectively. There was no significant difference in dosimetric characteristics and uniformity of internal density between the 2 RCs. The net fabrication times of RC{sub 3}DP and RC{sub C}MM were about 18 and 3 hours, respectively. Conclusions: The physical accuracy and dosimetric characteristics of RC{sub 3}DP were comparable with those of the conventional RC{sub C}MM, and significant system minimization was provided.

  2. Vector generator scan converter

    DOE Patents [OSTI]

    Moore, James M. (Livermore, CA); Leighton, James F. (Livermore, CA)

    1990-01-01T23:59:59.000Z

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

  3. Vector generator scan converter

    DOE Patents [OSTI]

    Moore, J.M.; Leighton, J.F.

    1988-02-05T23:59:59.000Z

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

  4. ULTRA-HIGH SURFACE AREA SINGLE AND MULTI-WALLED CARBON NANOTUBE 3-DIMENSIONAL HYBRID STRUCTURE

    E-Print Network [OSTI]

    Mellor-Crummey, John

    flexible electronic devices, membranes, sensors, and energy storage devices, the primary reason being surface area 3-dimensional hybrid nanostructure by combining carbon nanotube growth on two templates. This novel hybrid carbon nanostructure demonstrates an enhanced conductive surface area that paves the way

  5. 3-Dimensional, Solder-Free Interconnect Technology for High-Performance Power Modules

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , published in "Conference on Integrated Power Systems (CIPS), Nuremberg : Germany (2012)" #12;dimensional (3D) packaging of power modules in a compact stacked layer structure [3], [4], [5]. The proposed technologies can3-Dimensional, Solder-Free Interconnect Technology for High- Performance Power Modules Bassem

  6. Reprint from the Bulletin of the Belgian Mathematical Society Simon Stevin Lagrangian submanifolds in 3-dimensional

    E-Print Network [OSTI]

    Li, Haizhong

    of Project Euclid (Cornell University Library), an aggregation of electronic journals. It is available online classification of the Lagrangian submanifolds in 3-dimensional complex space forms with isotropic cubic tensor. 1 Mathematics Subject Classification : Primary 53C20; Secondary 53C42. Key words and phrases : Lagrangian

  7. DC systems with transformerless converters

    SciTech Connect (OSTI)

    Vithayathil, J.J.; Mittlestadt, W. [Bonneville Power Administration, Portland, OR (United States)] [Bonneville Power Administration, Portland, OR (United States); Bjoerklund, P.E. [ABB Power Systems AB, Ludvika (Sweden)] [ABB Power Systems AB, Ludvika (Sweden)

    1995-07-01T23:59:59.000Z

    A technical and economic feasibility study of HVDC systems without converter transformers is presented. The presentation includes proposed solutions to the drawback related to the absence of galvanic separation between the ac and dc systems, if the converter transformers are eliminated. The results show that HVDC systems without converter transformers are both technically and economically feasible. The cost savings can be substantial.

  8. Shear Unzipping of DNA

    E-Print Network [OSTI]

    Buddhapriya Chakrabarti; David R. Nelson

    2009-04-09T23:59:59.000Z

    We study theoretically the mechanical failure of a simple model of double stranded DNA under an applied shear. Starting from a more microscopic Hamiltonian that describes a sheared DNA, we arrive at a nonlinear generalization of a ladder model of shear unzipping proposed earlier by deGennes [deGennes P. G. C. R. Acad. Sci., Ser. IV; Phys., Astrophys. 2001, 1505]. Using this model and a combination of analytical and numerical methods, we study the DNA "unzipping" transition when the shearing force exceeds a critical threshold at zero temperature. We also explore the effects of sequence heterogeneity and finite temperature and discuss possible applications to determine the strength of colloidal nanoparticle assemblies functionalized by DNA.

  9. Bacteria in shear flow

    E-Print Network [OSTI]

    Marcos, Ph.D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    Bacteria are ubiquitous and play a critical role in many contexts. Their environment is nearly always dynamic due to the prevalence of fluid flow: creeping flow in soil, highly sheared flow in bodily conduits, and turbulent ...

  10. Solar thermionic energy converter experiment

    SciTech Connect (OSTI)

    Goodale, D.; Lieb, D.; Neale, D.

    1982-08-01T23:59:59.000Z

    A one-inch CVD converter was solar tested in a central receiver heliostat array at the Advanced Components Test Facility at the Georgia Institute of Technology. The test examined heat flux cycling control of the operating point and mounting arrangements. The converter was mounted directly in the solar image with no cavity. The input heat flux was 40-60 W/cm/sup 2/. The converter performance was comparable to combustion measurements made on the same diode. Thermal cycling caused no problems with converter operation. The converter showed no degradation after the test.

  11. Thermionic electric converter

    SciTech Connect (OSTI)

    Davis, E.D.

    1981-12-01T23:59:59.000Z

    A thermionic electric converter is disclosed wherein an externally located heat source causes electrons to be boiled off an electron emissive surface interiorly positioned on one end wall of an evacuated cylindrical chamber. The electrons are electrically focused and accelerated through the interior of an air core induction coil located within a transverse magnetic field, and subsequently are collected on the other end wall of the chamber functioning as a collecting plate. The emf generated in the induction coil by action of the transiting electron stream interacting with the transverse magnetic field is applied to an external circuit to perform work, thereby implementing a direct heat energy to electrical energy conversion.

  12. Cycloidal Wave Energy Converter

    SciTech Connect (OSTI)

    Stefan G. Siegel, Ph.D.

    2012-11-30T23:59:59.000Z

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

  13. Magnetohydrodynamic Shearing Waves

    E-Print Network [OSTI]

    Bryan M. Johnson

    2007-02-12T23:59:59.000Z

    I consider the nonaxisymmetric linear theory of a rotating, isothermal magnetohydrodynamic (MHD) shear flow. The analysis is performed in the shearing box, a local model of a thin disk, using a decomposition in terms of shearing waves, i.e., plane waves in a frame comoving with the shear. These waves do not have a definite frequency as in a normal mode decomposition, and numerical integration of a coupled set of amplitude equations is required to characterize their time dependence. Their generic time dependence, however, is oscillatory with slowly-varying frequency and amplitude, and one can construct accurate analytical solutions by applying the Wentzel-Kramers-Brillouin method to the full set of amplitude equations. The solutions have the following properties: 1) Their accuracy increases with wavenumber, so that most perturbations that fit within the disk are well-approximated as modes with time-dependent frequencies and amplitudes. 2) They can be broadly classed as incompressive and compressive perturbations, the former including the nonaxisymmetric extension of magnetorotationally unstable modes, and the latter being the extension of fast and slow modes to a differentially-rotating medium. 3) Wave action is conserved, implying that their energy varies with frequency. 4) Their shear stress is proportional to the slope of their frequency, so that they transport angular momentum outward (inward) when their frequency increases (decreases). The complete set of solutions constitutes a comprehensive linear test suite for numerical MHD algorithms that incorporate a background shear flow. I conclude with a brief discussion of possible astrophysical applications.

  14. Bidirectional buck boost converter

    DOE Patents [OSTI]

    Esser, A.A.M.

    1998-03-31T23:59:59.000Z

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero. 20 figs.

  15. Bidirectional buck boost converter

    DOE Patents [OSTI]

    Esser, Albert Andreas Maria (Niskayuna, NY)

    1998-03-31T23:59:59.000Z

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

  16. The 3-dimensional Einstein-Klein-Gordon system in characteristic numerical relativity

    E-Print Network [OSTI]

    W. Barreto; A. Da Silva; R. Gomez; L. Lehner; L. Rosales; J. Winicour

    2004-12-14T23:59:59.000Z

    We incorporate a massless scalar field into a 3-dimensional code for the characteristic evolution of the gravitational field. The extended 3-dimensional code for the Einstein--Klein--Gordon system is calibrated to be second order convergent. It provides an accurate calculation of the gravitational and scalar radiation at infinity. As an application, we simulate the fully nonlinear evolution of an asymmetric scalar pulse of ingoing radiation propagating toward an interior Schwarzschild black hole and compute the backscattered scalar and gravitational outgoing radiation patterns. The amplitudes of the scalar and gravitational outgoing radiation modes exhibit the predicted power law scaling with respect to the amplitude of the initial data. For the scattering of an axisymmetric scalar field, the final ring down matches the complex frequency calculated perturbatively for the $\\ell=2$ quasinormal mode.

  17. Converting Biomass to Products

    SciTech Connect (OSTI)

    Graybeal, Judith W.

    2006-06-01T23:59:59.000Z

    For nearly 30 years, PNNL has been developing and applying novel thermal, chemical and biological processes to convert biomass to industrial and consumer products, fuels and energy. Honors for technologies resulting from this research include the Presidential Green Chemistry Award and several Federal Laboratory Consortium and R&D 100 Awards. PNNL’s research and development activities address the complete processing scheme, from feedstock pretreatment to purified product recovery. The laboratory applies fundamental science and advanced engineering capabilities to biomass conversion and processing to ensure effective recovery of optimal value from biomass; carbohydrate polymer systems to maximize energy efficiencies; and micro-technology systems for separation and conversion processes. For example, bioproducts researchers in the laboratory’s Institute for Interfacial Catalysis develop and demonstrate the utility of new catalyst formulations for production of bio-based chemicals. This article describes a sampling of current and recent catalysis projects for biomass conversion.

  18. Self-powered microthermionic converter

    DOE Patents [OSTI]

    Marshall, Albert C.; King, Donald B.; Zavadil, Kevin R.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

    2004-08-10T23:59:59.000Z

    A self-powered microthermionic converter having an internal thermal power source integrated into the microthermionic converter. These converters can have high energy-conversion efficiencies over a range of operating temperatures. Microengineering techniques are used to manufacture the converter. The utilization of an internal thermal power source increases potential for mobility and incorporation into small devices. High energy efficiency is obtained by utilization of micron-scale interelectrode gap spacing. Alpha-particle emitting radioisotopes can be used for the internal thermal power source, such as curium and polonium isotopes.

  19. Thyristor converter simulation and analysis

    SciTech Connect (OSTI)

    Zhang, S.Y.

    1991-01-01T23:59:59.000Z

    In this paper we present a simulation on thyristor converters. The simulation features nonlinearity, non-uniform firing, and the commutations. Several applications such as a current regulation, a converter frequency characteristics analysis, and a power line disturbance analysis will be presented. 4 refs., 4 figs.

  20. MT3D: a 3 dimensional magnetotelluric modeling program (user's guide and documentation for Rev. 1)

    SciTech Connect (OSTI)

    Nutter, C.; Wannamaker, P.E.

    1980-11-01T23:59:59.000Z

    MT3D.REV1 is a non-interactive computer program written in FORTRAN to do 3-dimensional magnetotelluric modeling. A 3-D volume integral equation has been adapted to simulate the MT response of a 3D body in the earth. An integro-difference scheme has been incorporated to increase the accuracy. This is a user's guide for MT3D.REV1 on the University of Utah Research Institute's (UURI) PRIME 400 computer operating under PRIMOS IV, Rev. 17.

  1. PILOT and cosmic shear

    E-Print Network [OSTI]

    W. Saunders

    2008-01-29T23:59:59.000Z

    Cosmic shear offers a remarkbly clean way to measure the equation of state of the Universe and its evolution. Resolution over a wide field is paramount, and Antarctica offers unique possibilities in this respect. There is an order of magnitude gain in speed over temperate sites, or a factor three in surface density. This means that PILOT outperforms much larger telescopes elsewhere, and can compete with the proposed DUNE space mission. Keywords: Antarctic astronomy, Surveys, Adaptive optics, Weak lensing

  2. Thermionic-photovoltaic energy converter

    SciTech Connect (OSTI)

    Chubb, D. L.

    1985-07-09T23:59:59.000Z

    A thermionic-photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or galium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  3. Structural changes in block copolymer solution under shear flow as determined by nonequilibrium molecular dynamics

    E-Print Network [OSTI]

    Igor Rychkov; Kenichi Yoshikawa

    2003-10-06T23:59:59.000Z

    A nonequilibrium molecular dynamics computer simulation on microsegregated solutions of symmetrical diblock copolymers is reported. As the polymer concentration increases, the system undergoes phase transitions in the following order: body centered cubic (BCC) micelles, hexagonal (HEX) cylinders, gyroid (GYR) bicontinuous networks, and lamellae (L), which are the same morphologies that have been reported for block copolymer melts. Structural classification is based on the patterns of the anisotropic static structure factor and characteristic 3-dimensional images. The systems in the BCC micellar ($\\rho\\sigma^{3}=0.3$) and HEX cylindrical ($\\rho\\sigma^{3}=0.4$) phases were then subjected to a steady planar shear flow. In weak shear flow, the segregated domains in both systems tend to rearrange into sliding parallel close-packed layers with their normal in the direction of the shear gradient. At higher shear rates both systems adopt a perpendicular lamellar structure with the normal along the neutral direction. A further increase in the shear rate results in a decrease in lamellar spacing without any further structural transitions. Two critical shear rate values that correspond to the demarcation of different structural behaviors were found.

  4. Converting Biomass to High-Value Feedstocks

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

    Converting Biomass to High-Value Feedstocks Advanced feedstocks play an important role in economically and efficiently converting biomass into bioenergy products. Advanced...

  5. Sandia National Laboratories: wave energy converters

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

    marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between...

  6. Sandia National Laboratories: river current energy converters

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

    marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between...

  7. Sandia National Laboratories: tidal energy converters

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

    marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between...

  8. Shear viscosity of nuclear matter

    E-Print Network [OSTI]

    Jun Xu

    2013-02-01T23:59:59.000Z

    In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.

  9. A thermionic converter success story

    SciTech Connect (OSTI)

    Donovan, B.D.; Lamp, T.R. (Aerospace Power Division, Wright Laboratory Wright-Patterson AFB, OH 45433-6563 (United States)); Ramaligam, M.L. (UES, Inc. 4401 Dayton-Xenia Road, Dayton, OH 45432-1894 (United States))

    1993-01-20T23:59:59.000Z

    This paper summarizes the advanced out-of-core thermionic technology program being managed at Wright Laboratory: The Thermionic Critical Technology (TCT) Investigation. This program has been supported primarily by the United State Air Force for design and fabrication, and supported by Strategic Defense Initiative Organization (SDIO) for performance and life testing efforts. Converter design parameters, specifications, and performance testing data is summarized. Converters fabricated by Loral Electro Optical Systems (Loral EOS) under this program have exceeding performance requirements, and have demonstrated efficiencies as high as 14%.

  10. Power converters for parabolic dishes

    SciTech Connect (OSTI)

    Truscello, V.C.; Williams, A.N.

    1981-01-01T23:59:59.000Z

    The development status of receivers and power conversion units to be used with parabolic dish concentrators is presented. Applications are identified, and the key role played by the power converter element of the collector module is emphasized. The electrical output of the 11-meter-diameter dish modules which are being developed varies up to a maximum of about 25 kilowatts, depending on the thermodynamic cycle of the power converter. Three power conversion units are being developed: an organic Rankine, an air Brayton, and a Stirling. The development program for the receivers and the power conversion units is described in detail.

  11. The limited growth of vegetated shear layers

    E-Print Network [OSTI]

    Ghisalberti, M.

    In contrast to free shear layers, which grow continuously downstream, shear layers generated by submerged vegetation grow only to a finite thickness. Because these shear layers are characterized by coherent vortex structures ...

  12. Charge-pump voltage converter

    DOE Patents [OSTI]

    Brainard, John P. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

    2009-11-03T23:59:59.000Z

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  13. Development of a 3-Dimensional Dosimetry System for Leksell Gamma Knife-Perfexion

    E-Print Network [OSTI]

    Yoon, KyoungJun; Lee, DoHeui; Cho, ByungChul; Lee, SangWook; Ahn, SeungDo

    2015-01-01T23:59:59.000Z

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife-Perfexion TM (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S;Tb phosphor sheets for dosimetric measurements. Also, to compensate the lack of backscatter, we located a 1 cm thick PMMA plate downstream of the active layer. The PMMA plate was transparent for scintillation lights to reach the CCD with 1200x1200 pixels by a 5.2 um pitch. Using this system, three hundred images by a 0.2 mm slice gap were acquired under each of three collimator setups, i.e. 4 mm, 8 mm, and 16 mm, respectively. The 2D projected images taken by CCD camera were compared with the dose distributions measured by EBT3 films in the same conditions. All ...

  14. Data Management Plan GOALI: Novel 3-dimensional microphotonics for high-efficiency color-mixing to enable solid-state

    E-Print Network [OSTI]

    Tipple, Brett

    Data Management Plan GOALI: Novel 3-dimensional microphotonics for high-efficiency color-mixing to enable solid-state lighting. The objective of this GOALI proposal is to enable high-efficiency white and backed up on stand-alone computers in the (locked) lab of the PI. Research data will be stored in USpace

  15. The purpose of this study was to describe 3-dimensional scapular motion patterns during dynamic shoulder move-

    E-Print Network [OSTI]

    Karduna, Andrew

    was accomplished by inser- tion of 2 1.6-mm bone pins into the spine of the scapula in 8 healthy volunteers (5 men, 3 women). A small, 3- dimensional motion sensor was rigidly fixed to the scapular pins. Sensors were electromagnetic-based system and attached a motion sensor directly to the scapula with bone pins drilled

  16. Portable convertible blast effects shield

    DOE Patents [OSTI]

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A. (Livermore, CA)

    2011-03-15T23:59:59.000Z

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more frusto-conically-tapered telescoping rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration by the friction fit of adjacent pairs of frusto-conically-tapered rings to each other.

  17. Portable convertible blast effects shield

    DOE Patents [OSTI]

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

    2007-05-22T23:59:59.000Z

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

  18. Portable convertible blast effects shield

    DOE Patents [OSTI]

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler,; Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

    2010-10-26T23:59:59.000Z

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

  19. Collector for thermionic energy converter

    SciTech Connect (OSTI)

    Bell, R.L.

    1981-07-21T23:59:59.000Z

    An improved collector is provided for a thermionic energy converter. The collector comprises a p-type layer of a semiconductor material formed on an n-type layer of a semiconductor material. The p-n junction is maintained in a forward biased condition. The electron affinity of the exposed surface of the p-type layer is effectively lowered to a low level near zero by the presence of a work function lowering activator. The dissipation of energy during collection is reduced by the passage of electrons through the p-type layer in the metastable conduction band state. A significant portion of the electron current remains at the potential of the fermi level of the n-type layer rather than dropping to the fermi level of the p-type layer. Less energy is therefore dissipated as heat and a higher net power output is delivered from a thermionic energy converter incorporating the collector.

  20. Cell modulated DC/DC converter

    E-Print Network [OSTI]

    Warren, James Raymond, III

    2005-01-01T23:59:59.000Z

    A very high frequency converter roughly based on a class E topology is investigated for replacing a conventional boost converter circuit. The loss mechanisms in class E inverters are characterized, and metrics are developed ...

  1. Mapping the 3-D Dark Matter potential with weak shear

    E-Print Network [OSTI]

    D. J. Bacon; A. N. Taylor

    2002-12-11T23:59:59.000Z

    We investigate the practical implementation of Taylor's (2002) 3-dimensional gravitational potential reconstruction method using weak gravitational lensing, together with the requisite reconstruction of the lensing potential. This methodology calculates the 3-D gravitational potential given a knowledge of shear estimates and redshifts for a set of galaxies. We analytically estimate the noise expected in the reconstructed gravitational field, taking into account the uncertainties associated with a finite survey, photometric redshift uncertainty, redshift-space distortions, and multiple scattering events. In order to implement this approach for future data analysis, we simulate the lensing distortion fields due to various mass distributions. We create catalogues of galaxies sampling this distortion in three dimensions, with realistic spatial distribution and intrinsic ellipticity for both ground-based and space-based surveys. Using the resulting catalogues of galaxy position and shear, we demonstrate that it is possible to reconstruct the lensing and gravitational potentials with our method. For example, we demonstrate that a typical ground-based shear survey with redshift limit z=1 and photometric redshifts with error Delta z=0.05 is directly able to measure the 3-D gravitational potential for mass concentrations >10^14 M_\\odot between 0.1

  2. COMMUNITY ALERT INCIDENT: Catalytic Converter Thefts

    E-Print Network [OSTI]

    Rose, Michael R.

    converter is a part used to reduce the toxicity of emissions from an internal combustion engine. What can

  3. Shear shocks in fragile networks

    E-Print Network [OSTI]

    Stephan Ulrich; Nitin Upadhyaya; Bas van Opheusden; Vincenzo Vitelli

    2013-07-29T23:59:59.000Z

    A minimal model for studying the mechanical properties of amorphous solids is a disordered network of point masses connected by unbreakable springs. At a critical value of its mean connectivity, such a network becomes fragile: it undergoes a rigidity transition signaled by a vanishing shear modulus and transverse sound speed. We investigate analytically and numerically the linear and non-linear visco-elastic response of these fragile solids by probing how shear fronts propagate through them. Our approach, that we tentatively label shear front rheology, provides an alternative route to standard oscillatory rheology. In the linear regime, we observe at late times a diffusive broadening of the fronts controlled by an effective shear viscosity that diverges at the critical point. No matter how small the microscopic coefficient of dissipation, strongly disordered networks behave as if they were over-damped because energy is irreversibly leaked into diverging non-affine fluctuations. Close to the transition, the regime of linear response becomes vanishingly small: the tiniest shear strains generate strongly non-linear shear shock waves qualitatively different from their compressional counterparts in granular media. The inherent non-linearities trigger an energy cascade from low to high frequency components that keep the network away from attaining the quasi-static limit. This mechanism, reminiscent of acoustic turbulence, causes a super-diffusive broadening of the shock width.

  4. CONVERTIBLE BONDS IN A DEFAULTABLE DIFFUSION MODEL

    E-Print Network [OSTI]

    Jeanblanc, Monique

    CONVERTIBLE BONDS IN A DEFAULTABLE DIFFUSION MODEL Tomasz R. Bielecki Department of Applied Research Grant PS12918. #12;2 Convertible Bonds in a Defaultable Diffusion Model 1 Introduction In [4), such as Convertible Bonds (CB), and we provided a rigorous decomposition of a CB into a bond component and a (game

  5. Auxiliary resonant DC tank converter

    DOE Patents [OSTI]

    Peng, Fang Z. (Knoxville, TN)

    2000-01-01T23:59:59.000Z

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  6. Digital control of HVDC converters

    SciTech Connect (OSTI)

    Pilotto, L.A.S.; Roitman, M.; Alves, J.E.R.

    1989-05-01T23:59:59.000Z

    This paper presents the project of a completely digital HVDC converter controller based on a 16-bit microcomputer. It was decided to achieve as much as possible by software in order to minimize functions performed by external hardware. The presented design comprises software programmed functions such as a PID current control amplifier, voltage dependent current order limiters and an alpha-minimum symmetrization unit, among others. HVDC control principles are briefly reviewed and a detailed description of both the hardware and software structure of the controller is presented. The digital controller was implemented in an HVDC simulator and several dynamic performance tests demonstrated the efficiency of the proposed methodology.

  7. Converting Energy to Medical Progress

    Office of Scientific and Technical Information (OSTI)

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy, science, and technology-- Energy, science, and technologyConverting to

  8. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, Daniel T. (La Jolla, CA)

    1990-01-01T23:59:59.000Z

    A support is provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  9. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, D.T.

    1990-10-16T23:59:59.000Z

    A support is presented for use in a thermionic converted to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a large metal main support at the rear end that is attached to the housing, and metal main support. The spring structure can include a loose wafer captured between the Belleville springs.

  10. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, Daniel T. (La Jolla, CA)

    1990-01-01T23:59:59.000Z

    A support is provided for use in a thermionic converter to support an end an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housng, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  11. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, D.T.

    1989-07-06T23:59:59.000Z

    This document discusses a support provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs. 7 figs.

  12. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, D.T.

    1990-05-22T23:59:59.000Z

    This patent describes a support provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs.

  13. Conducting a 3D Converted Shear Wave Project to Reduce Exploration...

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

    * Funding for FY10 8,400,000 - Barriers * Permit: In case necessary, acquiring BLM drilling permits might effect the proposed timetable - Partners * ExplorTech LLC Wister...

  14. Estimation of shear-wave interval attenuation from mode-converted data Bharath Shekar1

    E-Print Network [OSTI]

    Tsvankin, Ilya

    Tsvankin1 ABSTRACT Interval attenuation measurements provide valuable infor- mation for reservoir characterization and lithology discrimi- nation. We extend the attenuation layer-stripping method of Behura of the material (Prasad and Nur, 2003), the pre- sence of aligned fluid-filled fractures (Chapman, 2003; Batzle et

  15. Sandia National Laboratories: wave energy converter

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

    release. This model has ... Sandia Funded to Model Power Pods for Utility-Scale Wave-Energy Converter On September 16, 2014, in Computational Modeling & Simulation, Energy,...

  16. New Catalyst Converts CO2 to Fuel

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

    a catalyst that improves their system for converting waste carbon dioxide (CO) into syngas, a precursor of gasoline and other energy-rich products, bringing the process closer...

  17. Bi-directional dc-dc Converter

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

    Purpose of Work for FY08 1. Vehicle modeling, simulation, and operation voltages optimization. 2. DC-DC Power converter and control modeling. 3. Silicon Carbide device...

  18. Sandia National Laboratories: current energy converter array...

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

    array optimization framework Current Energy Converter Array Optimization Framework On March 13, 2014, in Computational Modeling & Simulation, Energy, News, News & Events,...

  19. Sandia National Laboratories: ocean energy converters

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

    ocean energy converters DOE-Sponsored Reference Model Project Results Released On January 28, 2014, in Computational Modeling & Simulation, Energy, News, News & Events,...

  20. Measuring the cosmic shear in Fourier space

    E-Print Network [OSTI]

    Zhang, Jun

    2008-01-01T23:59:59.000Z

    Measuring the Cosmic Shear in Fourier Space Bernardeau F. ,the Cosmic Shear in Fourier Space Jun Zhang ? Department ofshould be carried out in Fourier space, in which the point

  1. Refraction of shear zones in granular materials

    E-Print Network [OSTI]

    Tamas Unger

    2007-01-08T23:59:59.000Z

    We study strain localization in slow shear flow focusing on layered granular materials. A heretofore unknown effect is presented here. We show that shear zones are refracted at material interfaces in analogy with refraction of light beams in optics. This phenomenon can be obtained as a consequence of a recent variational model of shear zones. The predictions of the model are tested and confirmed by 3D discrete element simulations. We found that shear zones follow Snell's law of light refraction.

  2. Shear viscosity of the quark matter

    E-Print Network [OSTI]

    Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

    2007-05-14T23:59:59.000Z

    We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.

  3. Shear viscosity and shear thinning in two-dimensional Yukawa , J. Goree2

    E-Print Network [OSTI]

    Goree, John

    Shear viscosity and shear thinning in two-dimensional Yukawa liquids Z. Donk´o1 , J. Goree2 , P using two different nonequi- librium molecular dynamics simulation methods. Shear viscosity values.e., the viscosity diminishes with increasing shear rate. It is expected that two-dimensional dusty plasmas

  4. Vacuum-insulated catalytic converter

    DOE Patents [OSTI]

    Benson, David K. (Golden, CO)

    2001-01-01T23:59:59.000Z

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  5. High performance, close-spaced thermionic converters

    SciTech Connect (OSTI)

    Dick, R.S.; Britt, E.J.; Fitzpatrick, G.O.; McVey, J.B.

    1983-08-01T23:59:59.000Z

    Near ideal performance in a Thermionic Energy Converter (TEC) can be obtained using extremely small (< 10 microns) interelectrode spacings. Previous efforts to build such converters have encountered engineering problems. A new type of converter, called SAVTEC (for Self-Adjusting, Versatile Thermionic Energy Converter) has been developed at Rasor Associates, Inc., as a practical way to achieve small spacings. It has been demonstrated to deliver improved performance over conventional, ignited-mode converters. A series of individual SAVTEC's have been built and tested. Two general configurations were built: in the first a single emitter support lead (0.25 mm wire) passes through a hole in the center of the collector, with the emitter being welded to it. In the second three smaller wires replace the center wire and are welded to the emitter perimeter. These converters have shown reliable, temperature controlled spacings of the emitter and collector. Reproducible spacing of 10 microns (0.4 mils) were achieved on several converters. This paper presents details of SAVTEC converter construction and performance, including volt-ampere curves.

  6. Apparatus for shearing spent nuclear fuel assemblies

    DOE Patents [OSTI]

    Weil, Bradley S. (Knoxville, TN); Metz, III, Curtis F. (Knoxville, TN)

    1980-01-01T23:59:59.000Z

    A method and apparatus are described for shearing spent nuclear fuel assemblies of the type comprising an array of fuel pins disposed within an outer metal shell or shroud. A spent fuel assembly is first compacted in a known manner and then incrementally sheared using fixed and movable shear blades having matched laterally projecting teeth which slidably intermesh to provide the desired shearing action. Incremental advancement of the fuel assembly after each shear cycle is limited to a distance corresponding to the lateral projection of the teeth to ensure fuel assembly breakup into small uniform segments which are amenable to remote chemical processing.

  7. Catalytic converter with thermoelectric generator

    SciTech Connect (OSTI)

    Parise, R.J.

    1998-07-01T23:59:59.000Z

    The unique design of an electrically heated catalyst (EHC) and the inclusion of an ECO valve in the exhaust of an internal combustion engine will meet the strict new emission requirements, especially at vehicle cold start, adopted by several states in this country as well as in Europe and Japan. The catalytic converter (CC) has been a most useful tool in pollution abatement for the automobile. But the emission requirements are becoming more stringent and, along with other improvements, the CC must be improved to meet these new standards. Coupled with the ECO valve, the EHC can meet these new emission limits. In an internal combustion engine vehicle (ICEV), approximately 80% of the energy consumed leaves the vehicle as waste heat: out the tail pipe, through the radiator, or convected/radiated off the engine. Included with the waste heat out the tail pipe are the products of combustion which must meet strict emission requirements. The design of a new CC is presented here. This is an automobile CC that has the capability of producing electrical power and reducing the quantity of emissions at vehicle cold start, the Thermoelectric Catalytic Power Generator. The CC utilizes the energy of the exothermic reactions that take place in the catalysis substrate to produce electrical energy with a thermoelectric generator. On vehicle cold start, the thermoelectric generator is used as a heat pump to heat the catalyst substrate to reduce the time to catalyst light-off. Thus an electrically heated catalyst (EHC) will be used to augment the abatement of tail pipe emissions. Included with the EHC in the exhaust stream of the automobile is the ECO valve. This valve restricts the flow of pollutants out the tail pipe of the vehicle for a specified amount of time until the EHC comes up to operating temperature. Then the ECO valve opens and allows the full exhaust, now treated by the EHC, to leave the vehicle.

  8. Controlled shear/tension fixture

    DOE Patents [OSTI]

    Hsueh, Chun-Hway (Knoxville, TN); Liu, Chain-tsuan (Knoxville, TN); George, Easo P. (Knoxville, TN)

    2012-07-24T23:59:59.000Z

    A test fixture for simultaneously testing two material test samples is provided. The fixture provides substantially equal shear and tensile stresses in each test specimens. By gradually applying a load force to the fixture only one of the two specimens fractures. Upon fracture of the one specimen, the fixture and the load train lose contact and the second specimen is preserved in a state of upset just prior to fracture. Particular advantages of the fixture are (1) to control the tensile to shear load on the specimen for understanding the effect of these stresses on the deformation behavior of advanced materials, (2) to control the location of fracture for accessing localized material properties including the variation of the mechanical properties and residual stresses across the thickness of advanced materials, (3) to yield a fractured specimen for strength measurement and an unfractured specimen for examining the microstructure just prior to fracture.

  9. A variable parameter thermionic energy converter

    E-Print Network [OSTI]

    Bragg, Bobby Joe

    1967-01-01T23:59:59.000Z

    Point Spacing Figure~ Power Jersus Spacing Wit?&out 'inmmum Power Point CHAPTER III THEORY OF OPERATION Brief History Vacuum diodes. The earliest known analysis and testing of therm- ionic energy converters was made on vacuum converters (i. e.... , a converter in which the interelectrode space is highly evacuated) by W. Schlicter in 1915 (2). He built a vacuum diode with a platinum emitter at 1000 0 yielding 1. 5 x 10 watt with an efficiency of about 10 $. These results, plus his analysis...

  10. New Perspectives on Wave Energy Converter Control 

    E-Print Network [OSTI]

    Price, Alexandra A E

    2009-01-01T23:59:59.000Z

    This work examines some of the fundamental problems behind the control of wave energy converters (WECs). Several new perspectives are presented to aid the understanding of the problem and the interpretation of the ...

  11. Sheared

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary Moniz9 SeptemberSetting the StageCanon! Sharedand

  12. Shear Viscosity of Quark Matter

    E-Print Network [OSTI]

    W. M. Alberico; S. Chiacchiera; H. Hansen; A. Molinari; M. Nardi

    2007-07-30T23:59:59.000Z

    We consider the shear viscosity of a system of quarks and its ratio to the entropy density above the critical temperature for deconfinement. Both quantities are derived and computed for different modeling of the quark self-energy, also allowing for a temperature dependence of the effective mass and width. The behaviour of the viscosity and the entropy density is argued in terms of the strength of the coupling and of the main characteristics of the quark self-energy. A comparison with existing results is also discussed.

  13. Improved Low-Temperature Performance of Catalytic Converters...

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

    Catalytic converters, installed on vehicles with internal combustion and diesel engines, convert the toxic byproducts of combustion to less toxic compounds. In two-way (lean...

  14. acid residues converted: Topics by E-print Network

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

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  15. ars projekt converted: Topics by E-print Network

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

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  16. angiotensin converting enzyme-3: Topics by E-print Network

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

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  17. angiotensin converting enzyme: Topics by E-print Network

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

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  18. SEP Success Story: State Energy Program Helping Arkansans Convert...

    Energy Savers [EERE]

    State Energy Program Helping Arkansans Convert to Compressed Natural Gas SEP Success Story: State Energy Program Helping Arkansans Convert to Compressed Natural Gas January 25,...

  19. Enterprise converting buses to biodiesel | Department of Energy

    Energy Savers [EERE]

    Enterprise converting buses to biodiesel Enterprise converting buses to biodiesel April 1, 2010 - 6:48pm Addthis Paul Lester Communications Specialist, Office of Energy Efficiency...

  20. Confined Cubic Blue Phases under Shear

    E-Print Network [OSTI]

    O. Henrich; K. Stratford; D. Marenduzzo; P. V. Coveney; M. E. Cates

    2012-03-14T23:59:59.000Z

    We study the behaviour of confined cubic blue phases under shear flow via lattice Boltzmann simulations. We focus on the two experimentally observed phases, blue phase I and blue phase II. The disinclination network of blue phase II continuously breaks and reforms under shear, leading to an oscillatory stress response in time. The oscillations are only regular for very thin samples. For thicker samples, the shear leads to a "stick-slip" motion of part of the network along the vorticity direction. Blue phase I responds very differently: its defect network undergoes seemingly chaotic rearrangements under shear, irrespective of system size.

  1. Vane shear determination of the visco-elastic shear modulus of submarine sediments

    E-Print Network [OSTI]

    Stevenson, Herbert Scott

    1973-01-01T23:59:59.000Z

    the process of deformation under shear can be considered and some of the factors affecting the viscoelastic nature of submarine clays can be identified. When the flocculent clay structure is subjected to shear the bonds between the particles ai e first... of MASTER OF SCIENCE December 1973 Major Subject: Civil Engineering VANE SHEAR DETERMINATION OF THE VISCOELASTIC SHEAR MODULUS OF SUBMARINE SEDIMENTS A Thesis by Herbert Scott Stevenson Approved as to style and content by: Chairman of Committ e M...

  2. Isolated and soft-switched power converter

    DOE Patents [OSTI]

    Peng, Fang Zheng (Knoxville, TN); Adams, Donald Joe (Knoxville, TN)

    2002-01-01T23:59:59.000Z

    An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors connected in series as a tank leg, and a pair of switching devices with anti-parallel clamping diodes coupled in series as resonant switches and clamping devices for the resonant leg. The power converter is well suited for DC/DC and DC/DC/AC power conversion applications in which high-voltage isolation, DC to DC voltage boost, bidirectional power flow, and a minimal number of conventional switching components are important design objectives. For example, the power converter is especially well suited to electric vehicle applications and load-side electric generation and storage systems, and other applications in which these objectives are important. The power converter may be used for many different applications, including electric vehicles, hybrid combustion/electric vehicles, fuel-cell powered vehicles with low-voltage starting, remote power sources utilizing low-voltage DC power sources, such as photovoltaics and others, electric power backup systems, and load-side electric storage and generation systems.

  3. Internal and Interface Shear Strength of

    E-Print Network [OSTI]

    Zornberg, Jorge G.

    1 Internal and Interface Shear Strength of Geosynthetic Clay Liners (GCLs): Additional Data by John Liners (GCLs): Additional Data Geosynthetic Clay Liners (GCLs) are prefabricated geocomposite materials., Zornberg, Jorge G., and Swan, Jr., Robert H. Internal and Interface Shear Strength of Geosynthetic Clay

  4. External ionization mechanisms for advanced thermionic converters

    SciTech Connect (OSTI)

    Hatziprokopiou, M.E.

    1981-01-01T23:59:59.000Z

    This work investigates ion generation and recombination mechanisms in the cesium plasma as they pertain to the advanced mode thermionic energy converter. The changes in plasma density and temperature within the converter have been studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation have been investigated in some detail, namely vibrationally excited N/sub 2/ as are energy source of ionization of Cs ions in a dc discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N/sub 2/-Cs mixture. The experimental data obtained and discussed in this work show that all three techniques - i.e. the non-LTE high-voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power - have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

  5. Particle acceleration efficiencies in astrophysical shear flows

    E-Print Network [OSTI]

    F. M. Rieger; P. Duffy

    2005-02-04T23:59:59.000Z

    The acceleration of energetic particles in astrophysical shear flows is analyzed. We show that in the presence of a non-relativistic gradual velocity shear, power law particle momentum distributions $f(p) \\propto p^{-(3+\\alpha)}$ may be generated, assuming a momentum-dependent scattering time $\\tau \\propto p^{\\alpha}$, with $\\alpha > 0$. We consider possible acceleration sites in astrophysical jets and study the conditions for efficient acceleration. It is shown, for example, that in the presence of a gradual shear flow and a gyro-dependent particle mean free path, synchrotron radiation losses no longer stop the acceleration once it has started to work efficiently. This suggests that shear acceleration may naturally account for a second, non-thermal population of energetic particles in addition to a shock-accelerated one. The possible relevance of shear acceleration is briefly discussed with reference to the relativistic jet in the quasar 3C 273.

  6. Shear viscosity of pion gas

    E-Print Network [OSTI]

    Eiji Nakano

    2007-03-21T23:59:59.000Z

    Using chiral perturbation theory we investigate the QCD shear viscosity ($\\eta $) to entropy density ($s$) ratio below the deconfinement temperature ($\\sim 170$ MeV) with zero baryon number density. It is found that $\\eta /s$ of QCD is monotonically decreasing in temperature ($T$) and reaches 0.6 with estimated $\\sim 50%$ uncertainty at T=120 MeV. A naive extrapolation of the leading order result shows that $\\eta /s$ reaches the $1/4\\pi $ minimum bound proposed by Kovtun, Son, and Starinets using string theory methods at $T\\sim 210$ MeV. This suggests a phase transition or cross over might occur at $T\\lesssim 210$ MeV in order for the bound to remain valid. Also, it is natural for $\\eta /s$ to stay close to the minimum bound around the phase transition temperature as was recently found in heavy ion collisions.

  7. Sustainability of Shear-Induced Permeability for EGS Reservoirs...

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

    Sustainability of Shear-Induced Permeability for EGS Reservoirs A Laboratory Study Sustainability of Shear-Induced Permeability for EGS Reservoirs A Laboratory Study...

  8. Characteristics of two thermionic converters with oxide collectors

    SciTech Connect (OSTI)

    Smith, E.A.; Huffman, F.N.

    1984-08-01T23:59:59.000Z

    Thermionic converters built with selected metal oxide coatings on their collectors have given enhanced performance at interelectrode spacings greater than 0.25 mm. The capability of such converters to operate efficiently at large interelectrode spacings is of interest for in-core thermionic power systems. Performance data are reported from one converter built with a collector having a coating of molybdenum sublimed in oxygen and a second converter containing an oxidized zirconium collector. The molybdenum oxide collector converter demonstrated enhanced performance.

  9. Switched-Mode Power Converter Programmable

    E-Print Network [OSTI]

    -line identification of converter dynamic responses [2, 5, 6], tuning of controller parameters based on identification dynamics followed by an automated algorithm to derive a controller design to meet a desired closed performance controller, an accurate parametric model is necessary. Particularly, a Z-domain transfer function

  10. Hybrid switch for resonant power converters

    DOE Patents [OSTI]

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09T23:59:59.000Z

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  11. Converting Centrifugal Chillers to HCFC-123 

    E-Print Network [OSTI]

    Siebert, B.

    1994-01-01T23:59:59.000Z

    of large water chillers in addressing the CFC issue. These owners, for a variety of reasons, chose to address the issue through the conversion of the existing equipment to an HCFC refrigerant. For each of the three owners, the option of converting...

  12. Chondroregulatory action of prolactin on proliferation and differentiation of mouse chondrogenic ATDC5 cells in 3-dimensional micromass cultures

    SciTech Connect (OSTI)

    Seriwatanachai, Dutmanee [Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok (Thailand)] [Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok (Thailand); Krishnamra, Nateetip [Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok (Thailand) [Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok (Thailand); Department of Physiology, Faculty of Science, Mahidol University, Bangkok (Thailand); Charoenphandhu, Narattaphol, E-mail: naratt@narattsys.com [Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok (Thailand) [Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok (Thailand); Department of Physiology, Faculty of Science, Mahidol University, Bangkok (Thailand)

    2012-03-30T23:59:59.000Z

    Highlights: Black-Right-Pointing-Pointer Mouse chondrogenic ATDC5 cells expressed PRL receptor mRNAs and proteins. Black-Right-Pointing-Pointer Low PRL concentration (10 ng/mL) increased chondrocyte viability and differentiation. Black-Right-Pointing-Pointer Higher PRL concentrations ( Greater-Than-Or-Slanted-Equal-To 100 ng/mL) decreased viability and increased apoptosis. -- Abstract: A recent investigation in lactating rats has provided evidence that the lactogenic hormone prolactin (PRL) increases endochondral bone growth and bone elongation, presumably by accelerating apoptosis of hypertrophic chondrocytes in the growth plate and/or subsequent chondrogenic matrix mineralization. Herein, we demonstrated the direct chondroregulatory action of PRL on proliferation, differentiation and apoptosis of chondrocytes in 3-dimensional micromass culture of mouse chondrogenic ATDC5 cell line. The results showed that ATDC5 cells expressed PRL receptor (PRLR) transcripts, and responded typically to PRL by downregulating PRLR expression. Exposure to a low PRL concentration of 10 ng/mL, comparable to the normal levels in male and non-pregnant female rats, increased chondrocyte viability, differentiation, proteoglycan accumulation, and mRNA expression of several chondrogenic differentiation markers, such as Sox9, ALP and Hspg2. In contrast, high PRL concentrations of Greater-Than-Or-Slanted-Equal-To 100 ng/mL, comparable to the levels in pregnancy or lactation, decreased chondrocyte viability by inducing apoptosis, with no effect on chondrogenic marker expression. It could be concluded that chondrocytes directly but differentially responded to non-pregnant and pregnant/lactating levels of PRL, thus suggesting the stimulatory effect of PRL on chondrogenesis in young growing individuals, and supporting the hypothesis of hypertrophic chondrocyte apoptosis in the growth plate of lactating rats.

  13. Joint environmental assessment for western NPR-1 3-dimensional seismic project at Naval Petroleum Reserve No. 1, Kern County, California

    SciTech Connect (OSTI)

    NONE

    1996-05-01T23:59:59.000Z

    The Department of Energy (DOE), in conjunction with the Bureau of Land Management (BLM), has prepared an Environmental Assessment (DOE/EA-1124) to identify and evaluate the potential environmental impacts of the proposed geophysical seismic survey on and adjacent to the Naval Petroleum Reserve No.1 (NPR-1), located approximately 35 miles west of Bakersfield, California. NPR-1 is jointly owned and operated by the federal government and Chevron U.S.A. Production Company. The federal government owns about 78 percent of NPR-1, while Chevron owns the remaining 22 percent. The government`s interest is under the jurisdiction of DOE, which has contracted with Bechtel Petroleum Operations, Inc. (BPOI) for the operation and management of the reserve. The 3-dimensional seismic survey would take place on NPR-1 lands and on public and private lands adjacent to NPR-1. This project would involve lands owned by BLM, California Department of Fish and Game (CDFG), California Energy Commission (CEC), The Nature Conservancy, the Center for Natural Lands Management, oil companies (Chevron, Texaco, and Mobil), and several private individuals. The proposed action is designed to provide seismic data for the analysis of the subsurface geology extant in western NPR-1 with the goal of better defining the commercial limits of a currently producing reservoir (Northwest Stevens) and three prospective hydrocarbon bearing zones: the {open_quotes}A Fan{close_quotes} in Section 7R, the 19R Structure in Section 19R, and the 13Z Structure in Section 13Z. Interpreting the data is expected to provide NPR-1 owners with more accurate locations of structural highs, faults, and pinchouts to maximize the recovery of the available hydrocarbon resources in western NPR-1. Completion of this project is expected to increase NPR-1 recoverable reserves, and reduce the risks and costs associated with further exploration and development in the area.

  14. Shear Viscosity from Effective Couplings of Gravitons

    E-Print Network [OSTI]

    Rong-Gen Cai; Zhang-Yu Nie; Ya-Wen Sun

    2008-12-12T23:59:59.000Z

    We calculate the shear viscosity of field theories with gravity duals using Kubo-formula by calculating the Green function of dual transverse gravitons and confirm that the value of the shear viscosity is fully determined by the effective coupling of transverse gravitons on the horizon. We calculate the effective coupling of transverse gravitons for Einstein and Gauss-Bonnet gravities coupled with matter fields, respectively. Then we apply the resulting formula to the case of AdS Gauss-Bonnet gravity with $F^4$ term corrections of Maxwell field and discuss the effect of $F^4$ terms on the ratio of the shear viscosity to entropy density.

  15. Combustion converter development for topping and cogeneration applications

    SciTech Connect (OSTI)

    Goodale, D.; Lieb, D.; Miskolczy, G.; Moffat, A.

    1983-08-01T23:59:59.000Z

    This paper discusses the development of combustion-heated thermionic converters. Combustion applications pose a materials problem that does not exist for thermionic converters used in the vacuum of outer space. The high-temperature components of a thermionic converter must be protected from the oxidizing terrestrial environment. A layer of silicon carbide provides the most satisfactory protective coating, or ''hot shell,'' for the emitter and lead of a combustion-heated thermionic converter. Four areas of work aimed at developing combustion heated thermionic converters will be discussed: improving the performance of the two-inch torispherical converter, modifications to the converter so that it may be used in multi-converter modules, the construction of a thermionic cogeneration test furnace, and a converter life test in an oil-fired furnace.

  16. A square root analog to digital converter to optimally convert photonic signals for computed tomography

    E-Print Network [OSTI]

    Bieniosek, Matthew (Matthew F.)

    2010-01-01T23:59:59.000Z

    The arrival of photons at a given location is a Poisson process with an associated shot noise which rises with the square root of the number of photons received. An analog-to-digital converter (ADC) with a square root ...

  17. Particle acceleration in astrophysical shear flows

    E-Print Network [OSTI]

    Frank M. Rieger; Peter Duffy

    2005-01-10T23:59:59.000Z

    We consider the acceleration of particles due to a velocity shear in relativistic astrophysical flows. The basic physical picture and the formation of power law momentum spectra is discussed for a non-relativistic velocity field using a microscopic approach. We identify possible sites for shear acceleration in relativistic astrophysical jets and analyze their associated acceleration timescales. It is shown in particular that for a mean scattering time $\\tau$ scaling with the gyro-radius, the acceleration timescale for gradual shear scales in the same manner as the synchrotron cooling timescale, so that losses may no longer be able to stop the acceleration once it has started to work efficiently. Finally, the possible role of shear acceleration is discussed with reference to the relativistic jet in the quasar 3C~273.

  18. Shear viscosity of degenerate electron matter

    E-Print Network [OSTI]

    P. S. Shternin

    2008-03-27T23:59:59.000Z

    We calculate the partial electron shear viscosity $\\eta_{ee}$ limited by electron-electron collisions in a strongly degenerate electron gas taking into account the Landau damping of transverse plasmons. The Landau damping strongly suppresses $\\eta_{ee}$ in the domain of ultrarelativistic degenerate electrons and modifies its %asymptotic temperature behavior. The efficiency of the electron shear viscosity in the cores of white dwarfs and envelopes of neutron stars is analyzed.

  19. Shear banding in soft glassy materials

    E-Print Network [OSTI]

    Suzanne M. Fielding

    2014-08-20T23:59:59.000Z

    Many soft materials, including foams, dense emulsions, micro gel bead suspensions, star polymers, dense packing of surfactant onion micelles, and textured morphologies of liquid crystals, share the basic "glassy" features of structural disorder and metastability. These in turn give rise to several notable features in the low frequency shear rheology (deformation and flow properties) of these materials: in particular, the existence of a yield stress below which the material behaves like a solid, and above which it flows like a liquid. In the last decade, intense experimental activity has also revealed that these materials often display a phenomenon known as shear banding, in which the flow profile across the shear cell exhibits macroscopic bands of different viscosity. Two distinct classes of yield stress fluid have been identified: those in which the shear bands apparently persist permanently (for as long as the flow remains applied), and those in which banding arises only transiently during a process in which a steady flowing state is established out of an initial rest state (for example, in a shear startup or step stress experiment). After surveying the motivating experimental data, we describe recent progress in addressing it theoretically, using the soft glassy rheology model and a simple fluidity model. We also briefly place these theoretical approaches in the context of others in the literature, including elasto-plastic models, shear transformation zone theories, and molecular dynamics simulations. We discuss finally some challenges that remain open to theory and experiment alike.

  20. Evolution of shear zones in granular materials

    E-Print Network [OSTI]

    Balazs Szabo; Janos Torok; Ellak Somfai; Sandra Wegner; Ralf Stannarius; Axel Bose; Georg Rose; Frank Angenstein; Tamas Borzsonyi

    2014-08-07T23:59:59.000Z

    The evolution of wide shear zones (or shear bands) was investigated experimentally and numerically for quasistatic dry granular flows in split bottom shear cells. We compare the behavior of materials consisting of beads, irregular grains (e.g. sand) and elongated particles. Shearing an initially random sample, the zone width was found to significantly decrease in the first stage of the process. The characteristic shear strain associated with this decrease is about unity and it is systematically increasing with shape anisotropy, i.e. when the grain shape changes from spherical to irregular (e.g. sand) and becomes elongated (pegs). The strongly decreasing tendency of the zone width is followed by a slight increase which is more pronounced for rod like particles than for grains with smaller shape anisotropy (beads or irregular particles). The evolution of the zone width is connected to shear induced density change and for nonspherical particles it also involves grain reorientation effects. The final zone width is significantly smaller for irregular grains than for spherical beads.

  1. An economical single to three phase converter for induction motors

    E-Print Network [OSTI]

    Di Zerega, Philp Van Uytandaele

    1994-01-01T23:59:59.000Z

    There are several different types of single to three phase converters for induction motors available today. However, many of the presently available phase converters suffer from disadvantages such as high cost or low performance. An economical...

  2. DOE Announces Webinars on the Wave Energy Converter Prize, the...

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

    DOE Announces Webinars on the Wave Energy Converter Prize, the Best of the Clean Cities Tools and Resources, and More DOE Announces Webinars on the Wave Energy Converter Prize, the...

  3. Automated Synthesis Tool for Design Optimization of Power Electronic Converters 

    E-Print Network [OSTI]

    Mirjafari, Mehran

    2013-01-09T23:59:59.000Z

    module-integrated photovoltaic inverter is also optimized for efficiency, volume and reliability. An actual converter is constructed using commercial off-the-shelf components. The converter design is chosen as close as possible to a point obtained...

  4. An economical single to three phase converter for induction motors 

    E-Print Network [OSTI]

    Di Zerega, Philp Van Uytandaele

    1994-01-01T23:59:59.000Z

    There are several different types of single to three phase converters for induction motors available today. However, many of the presently available phase converters suffer from disadvantages such as high cost or low performance. An economical...

  5. Digital radix converters for high accuracy data conversion 

    E-Print Network [OSTI]

    Ghanta, Venkataratnam Chowdary

    1993-01-01T23:59:59.000Z

    A sub-binary radix Digital to Analog converter(DAC) which achieves high effective resolution is demonstrated. The converter does not have any built-in-self calibration mechanisms, but achieves high resolution and accuracy through the sub...

  6. Heat Pump Water Heater using Solid-State Energy Converters |...

    Energy Savers [EERE]

    Heat Pump Water Heater using Solid-State Energy Converters Heat Pump Water Heater using Solid-State Energy Converters Sheetak will work on developing a full scale prototype of its...

  7. A low-power reconfigurable analog-to-digital converter

    E-Print Network [OSTI]

    Gulati, Kush

    2001-01-01T23:59:59.000Z

    This thesis presents the concept, theory and design of a low power CMOS analog-to-digital converter that can digitize signals over a wide range of bandwidth and resolution with adaptive power consumption. The converter ...

  8. A transient model for a cesium vapor thermionic converter. [Cs

    SciTech Connect (OSTI)

    El-Genk, M.S.; Murray, C.S.; Chaudhuri, S. (Institute for Space Nuclear Power Studies, Department of Chemical and Nuclear Engineering, The University of New Mexico, Albuquerque, New Mexico (USA))

    1991-01-10T23:59:59.000Z

    This paper presents an analytical model for simulating the transient and steady-state operation of cesium vapor thermionic converters. A parametric analysis is performed to assess the transient response of the converter to changes in fission power and width of interelectrode gap. The model optimizes the converter performance for maximum electric power to the load.(AIP)

  9. Modelling and geometry optimisation of wave energy converters

    E-Print Network [OSTI]

    Nørvåg, Kjetil

    Modelling and geometry optimisation of wave energy converters Adi Kurniawan Supervisors: Prof;Research questions Modelling How to develop more realistic wave energy converter (WEC) models while wave energy converter (WEC) models while at the same time reduce their simulation time? Optimisation

  10. Multiport Converter Topologies for Distributed Energy System Applications 

    E-Print Network [OSTI]

    Hawke, Joshua

    2014-07-28T23:59:59.000Z

    technologies into singular systems, there is a growing appetite for multiport converter (MPC) design. In response, three unique DER MPC topologies are presented: the power sharing converter (PSC), the multi-level nine switch converter (ML9SC), and the modular...

  11. A Dual Supply Buck Converter with Improved Light Load Efficiency

    E-Print Network [OSTI]

    Chen, Hui

    2013-05-02T23:59:59.000Z

    ................................................................................................ 1 1.2 Thesis Organization.................................................................................................. 3 2. BACKGROUND OF BUCK CONVERTER ................................................................ 4 2.1 DC-DC Converter... ...................................................... 2 Fig. 2. 1. A basic DC-DC converter ................................................................................... 5 Fig. 2. 2. Basic topology of a close loop linear regulator................................................... 6 Fig. 2. 3...

  12. Pressure-shear experiments on granular materials.

    SciTech Connect (OSTI)

    Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Thornhill, Tom Finley, III (, Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John; Alexander, C. Scott (Sandia National Laboratories, Albuquerque, NM)

    2011-10-01T23:59:59.000Z

    Pressure-shear experiments were performed on granular tungsten carbide and sand using a newly-refurbished slotted barrel gun. The sample is a thin layer of the granular material sandwiched between driver and anvil plates that remain elastic. Because of the obliquity, impact generates both a longitudinal wave, which compresses the sample, and a shear wave that probes the strength of the sample. Laser velocity interferometry is employed to measure the velocity history of the free surface of the anvil. Since the driver and anvil remain elastic, analysis of the results is, in principal, straightforward. Experiments were performed at pressures up to nearly 2 GPa using titanium plates and at higher pressure using zirconium plates. Those done with the titanium plates produced values of shear stress of 0.1-0.2 GPa, with the value increasing with pressure. On the other hand, those experiments conducted with zirconia anvils display results that may be related to slipping at an interface and shear stresses mostly at 0.1 GPa or less. Recovered samples display much greater particle fracture than is observed in planar loading, suggesting that shearing is a very effective mechanism for comminution of the grains.

  13. Shear induced rigidity in athermal materials: a unified statistical framework

    E-Print Network [OSTI]

    Sumantra Sarkar; Bulbul Chakraborty

    2015-02-18T23:59:59.000Z

    Recent studies of athermal systems such as dry grains and dense, non-Brownian suspensions have shown that shear can lead to solidification through the process of shear jamming in grains and discontinuous shear thickening in suspensions. The similarities observed between these two distinct phenomena suggest that the physical processes leading to shear-induced rigidity in athermal materials are universal. We present a non-equilibrium statistical mechanics model, which exhibits the phenomenology of these shear-driven transitions: shear jamming and discontinuous shear thickening in different regions of the predicted phase diagram. Our analysis identifies the crucial physical processes underlying shear-driven rigidity transitions, and clarifies the distinct roles played by shearing forces and the density of grains.

  14. Voltage balanced multilevel voltage source converter system

    DOE Patents [OSTI]

    Peng, F.Z.; Lai, J.S.

    1997-07-01T23:59:59.000Z

    Disclosed is a voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means. 15 figs.

  15. Solid state transport-based thermoelectric converter

    DOE Patents [OSTI]

    Hu, Zhiyu

    2010-04-13T23:59:59.000Z

    A solid state thermoelectric converter includes a thermally insulating separator layer, a semiconducting collector and an electron emitter. The electron emitter comprises a metal nanoparticle layer or plurality of metal nanocatalyst particles disposed on one side of said separator layer. A first electrically conductive lead is electrically coupled to the electron emitter. The collector layer is disposed on the other side of the separator layer, wherein the thickness of the separator layer is less than 1 .mu.m. A second conductive lead is electrically coupled to the collector layer.

  16. convert program | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA Approved: 5-13-14Russian NuclearNational5/%2A en Office ofcontracting |convert

  17. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    Power Maximization in Wave-Energy Converters Using Sampled-design optimization of wave energy converters con- sistingN. Sahinkaya. A review of wave energy converter technology.

  18. Shear Viscosity of a Hot Pion Gas

    E-Print Network [OSTI]

    Robert Lang; Norbert Kaiser; Wolfram Weise

    2012-09-04T23:59:59.000Z

    The shear viscosity of an interacting pion gas is studied using the Kubo formalism as a microscopic description of thermal systems close to global equilibrium. We implement the skeleton expansion in order to approximate the retarded correlator of the viscous part of the energy-momentum tensor. After exploring this in $g\\phi^4$ theory we show how the skeleton expansion can be consistently applied to pions in chiral perturbation theory. The shear viscosity $\\eta$ is determined by the spectral width, or equivalently, the mean free path of pions in the heat bath. We derive a new analytical result for the mean free path which is well-conditioned for numerical evaluation and discuss the temperature and pion-mass dependence of the mean free path and the shear viscosity. The ratio $\\eta/s$ of the interacting pion gas exceeds the lower bound $1/4\\pi$ from AdS/CFT correspondence.

  19. Integrated Solar Upper Stage (ISUS) thermionic converter string evaluation

    SciTech Connect (OSTI)

    Talbot, G.J.; Ramsey, W.D.; Chao, C.J.

    1998-07-01T23:59:59.000Z

    A serial string of eighth (8) thermionic converters were performance tested at New Mexico Engineering Research Institute (NMERI) by Frank Wyant et al1. The tests results from the second String Thermionic Assembly Research Testbed (START II) produced less than one half the expected power based on individual converter performance tests. Seven of the eight converters were returned to Lockheed Martin Information Systems-EOS for performance evaluation. Six of the seven produced nominal performance while the seventh converter showed a drastic reduction in performance due to a cesium leak to atmosphere. Several models were proposed to explain why the individual converter performance differed so markedly from the START II serial array. This paper discusses the models, evaluates model validity and compares the models with results from a tow converter serial test using of the returned START II converters.

  20. Converting online algorithms to local computation algorithms

    E-Print Network [OSTI]

    Mansour, Yishay; Vardi, Shai; Xie, Ning

    2012-01-01T23:59:59.000Z

    We propose a general method for converting online algorithms to local computation algorithms by selecting a random permutation of the input, and simulating running the online algorithm. We bound the number of steps of the algorithm using a query tree, which models the dependencies between queries. We improve previous analyses of query trees on graphs of bounded degree, and extend the analysis to the cases where the degrees are distributed binomially, and to a special case of bipartite graphs. Using this method, we give a local computation algorithm for maximal matching in graphs of bounded degree, which runs in time and space O(log^3 n). We also show how to convert a large family of load balancing algorithms (related to balls and bins problems) to local computation algorithms. This gives several local load balancing algorithms which achieve the same approximation ratios as the online algorithms, but run in O(log n) time and space. Finally, we modify existing local computation algorithms for hypergraph 2-color...

  1. Shear Viscosity of a Unitary Fermi Gas

    E-Print Network [OSTI]

    Gabriel Wlaz?owski; Piotr Magierski; Joaquín E. Drut

    2012-07-12T23:59:59.000Z

    We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s. The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.2 hbar/kB, which almost saturates the Kovtun-Son-Starinets universal value hbar/(4 pi kB).

  2. Energetic particle acceleration in shear layers

    E-Print Network [OSTI]

    M. Ostrowski

    1999-11-05T23:59:59.000Z

    A plasma velocity shear layer and/or a tangential flow discontinuity provide conditions allowing for energetic particle acceleration. We review such acceleration processes acting both in non-relativistic and in relativistic flows. In heliospheric conditions shear layers can provide particles with energies compatible with the observed values (from several keV up to MeV), while in relativistic extragalactic jets proton energies even in excess of 10^{19} eV can be obtained. Application of the discussed theory to particular astrophysical objects is severely limited by inadequate knowledge of local physical conditions.

  3. Shear strain localization in elastodynamic rupture simulations

    E-Print Network [OSTI]

    Daub, Eric G; Carlson, Jean M

    2008-01-01T23:59:59.000Z

    We study strain localization as an enhanced velocity weakening mechanism on earthquake faults. Fault friction is modeled using Shear Transformation Zone (STZ) Theory, a microscopic physical model for non-affine rearrangements in granular fault gouge. STZ Theory is implemented in spring slider and dynamic rupture models of faults. We compare dynamic shear localization to deformation that is uniform throughout the gouge layer, and find that localized slip enhances the velocity weakening of the gouge. Localized elastodynamic ruptures have larger stress drops and higher peak slip rates than ruptures with homogeneous strain.

  4. Dynamic Modes of Red Blood Cells in Oscillatory Shear Flow

    E-Print Network [OSTI]

    Hiroshi Noguchi

    2010-06-12T23:59:59.000Z

    The dynamics of red blood cells (RBCs) in oscillatory shear flow was studied using differential equations of three variables: a shape parameter, the inclination angle $\\theta$, and phase angle $\\phi$ of the membrane rotation. In steady shear flow, three types of dynamics occur depending on the shear rate and viscosity ratio. i) tank-treading (TT): $\\phi$ rotates while the shape and $\\theta$ oscillate. ii) tumbling (TB): $\\theta$ rotates while the shape and $\\phi$ oscillate. iii) intermediate motion: both $\\phi$ and $\\theta$ rotate synchronously or intermittently. In oscillatory shear flow, RBCs show various dynamics based on these three motions. For a low shear frequency with zero mean shear rate, a limit-cycle oscillation occurs, based on the TT or TB rotation at a high or low shear amplitude, respectively. This TT-based oscillation well explains recent experiments. In the middle shear amplitude, RBCs show an intermittent or synchronized oscillation. As shear frequency increases, the vesicle oscillation becomes delayed with respect to the shear oscillation. At a high frequency, multiple limit-cycle oscillations coexist. For a high mean shear rate with small shear oscillation, the shape and $\\theta$ oscillate in the TT motion but only one attractor exists even at high shear frequencies. The measurement of these oscillatory modes is a promising tool for quantifying the viscoelasticity of RBCs and synthetic capsules.

  5. Shear and Extensional Rheology of Cellulose/Ionic Liquid Solutions

    E-Print Network [OSTI]

    Haward, Simon J.

    In this study, we characterize the shear and extensional rheology of dilute to semidilute solutions of cellulose in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIAc). In steady shear flow, the semidilute solutions ...

  6. Title of dissertation: TURBULENT SHEAR FLOW IN A RAPIDLY ROTATING

    E-Print Network [OSTI]

    Lathrop, Daniel P.

    ABSTRACT Title of dissertation: TURBULENT SHEAR FLOW IN A RAPIDLY ROTATING SPHERICAL ANNULUS Daniel S. Zimmerman, Doctor of Philosophy, 2010 Dissertation directed by: Professor Daniel P. Lathrop Department of Physics This dissertation presents experimental measurements of torque, wall shear stress

  7. Turbulent Transport in Tokamak Plasmas with Rotational Shear

    SciTech Connect (OSTI)

    Barnes, M.; Highcock, E. G. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP (United Kingdom); Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Parra, F. I.; Schekochihin, A. A. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP (United Kingdom); Cowley, S. C.; Roach, C. M. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2011-04-29T23:59:59.000Z

    Nonlinear gyrokinetic simulations are conducted to investigate turbulent transport in tokamak plasmas with rotational shear. At sufficiently large flow shears, linear instabilities are suppressed, but transiently growing modes drive subcritical turbulence whose amplitude increases with flow shear. This leads to a local minimum in the heat flux, indicating an optimal ExB shear value for plasma confinement. Local maxima in the momentum fluxes are observed, implying the possibility of bifurcations in the ExB shear. The critical temperature gradient for the onset of turbulence increases with flow shear at low flow shears; at higher flow shears, the dependence of heat flux on temperature gradient becomes less stiff. The turbulent Prandtl number is found to be largely independent of temperature and flow gradients, with a value close to unity.

  8. Shear-wave splitting and reservoir crack characterization: the...

    Open Energy Info (EERE)

    Shear-wave splitting and reservoir crack characterization: the Coso geothermal field Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Shear-wave...

  9. Variational bounds for the shear viscosity of gelling melts

    E-Print Network [OSTI]

    Claas H. Köhler; Henning Löwe; Peter Müller; Annette Zippelius

    2007-05-03T23:59:59.000Z

    We study shear stress relaxation for a gelling melt of randomly crosslinked, interacting monomers. We derive a lower bound for the static shear viscosity $\\eta$, which implies that it diverges algebraically with a critical exponent $k\\ge 2\

  10. Shear viscosity of CFT plasma at finite coupling

    E-Print Network [OSTI]

    Alex Buchel

    2008-05-29T23:59:59.000Z

    We present evidence for the universality of the shear viscosity of conformal gauge theory plasmas beyond infinite coupling. We comment of subtleties of computing the shear viscosity in effective models of gauge/gravity correspondence rather than in string theory.

  11. Shear Viscosity from the Effective Coupling of Gravitons

    E-Print Network [OSTI]

    Rong-Gen Cai; Zhang-Yu Nie; Ya-Wen Sun

    2010-07-14T23:59:59.000Z

    We review the progress in the holographic calculation of shear viscosity for strongly coupled field theories. We focus on the calculation of shear viscosity from the effective coupling of transverse gravitons and present some explicit examples.

  12. Modeling of strain rate effects on clay in simple shear 

    E-Print Network [OSTI]

    Jung, Byoung Chan

    2006-08-16T23:59:59.000Z

    in monotonic and cyclic simple shear tests. Nevertheless, the few available experimental results cover a very limited range of loading conditions and rates. The existing literature established that the soil response display a unique relationship between shear...

  13. ERRATUM DARCY SHEAR STRESS MICHEL LOUGE

    E-Print Network [OSTI]

    Lipson, Michal

    ERRATUM ­ DARCY SHEAR STRESS MICHEL LOUGE This document arises from a conversation with Renaud paper on sand ripples [1], we state "A consequence of equation (9) is that µ(1 - )[( v) + ( v)T ] 0. The viscous macroscopic Ergun's equation is (1) u = -(K/µ) p, where u (1 - )v is the superficial gas velocity

  14. Hydrodynamic Modeling and the QGP Shear Viscosity

    E-Print Network [OSTI]

    Huichao Song

    2012-07-10T23:59:59.000Z

    In this article, we will briefly review the recent progress on hydrodynamic modeling and the extraction of the quark-gluon plasma (QGP) specific shear viscosity with an emphasis on results obtained from the hybrid model VISHNU that couples viscous hydrodynamics for the macroscopic expansion of the QGP to the hadron cascade model for the microscopic evolution of the late hadronic stage.

  15. Shear viscosity of a nonperturbative gluon plasma

    E-Print Network [OSTI]

    Dmitri Antonov

    2012-02-10T23:59:59.000Z

    Shear viscosity is evaluated within a model of the gluon plasma, which is based entirely on the stochastic nonperturbative fields. We consider two types of excitations of such fields, which are characterized by the thermal correlation lengths ~ 1/(g^2 T) and ~ 1/(g^4 T), where "g" is the finite-temperature Yang-Mills coupling. Excitations of the first type correspond to the genuine nonperturbative stochastic Yang-Mills fields, while excitations of the second type mimic the known result for the shear viscosity of the perturbative Yang-Mills plasma. We show that the excitations of the first type produce only an O(g^{10})-correction to this result. Furthermore, a possible interference between excitations of these two types yields a somewhat larger, O(g^7), correction to the leading perturbative Yang-Mills result. Our analysis is based on the Fourier transformed Euclidean Kubo formula, which represents an integral equation for the shear spectral density. This equation is solved by seeking the spectral density in the form of the Lorentzian Ans\\"atze, whose widths are defined by the two thermal correlation lengths and by their mean value, which corresponds to the said interference between the two types of excitations. Thus, within one and the same formalism, we reproduce the known result for the shear viscosity of the perturbative Yang-Mills plasma, and account for possible nonperturbative corrections to it.

  16. Internal and Interface Shear Strength of

    E-Print Network [OSTI]

    Zornberg, Jorge G.

    i Internal and Interface Shear Strength of Geosynthetic Clay Liners (GCLs) by John Scott Mc Strength of Geosynthetic Clay Liners (GCLs) Geosynthetic Clay Liners (GCLs) are prefabricated geocomposite materials used as an alternative to compacted clay liners in hydraulic barriers. They often offer hydraulic

  17. Modular Power Converters for PV Applications

    SciTech Connect (OSTI)

    Ozpineci, Burak [ORNL; Tolbert, Leon M [ORNL

    2012-05-01T23:59:59.000Z

    This report describes technical opportunities to serve as parts of a technological roadmap for Shoals Technologies Group in power electronics for PV applications. There are many different power converter circuits that can be used for solar inverter applications. The present applications do not take advantage of the potential for using common modules. We envision that the development of a power electronics module could enable higher reliability by being durable and flexible. Modules would have fault current limiting features and detection circuits such that they can limit the current through the module from external faults and can identify and isolate internal faults such that the remaining modules can continue to operate with only minimal disturbance to the utility or customer. Development of a reliable, efficient, low-cost, power electronics module will be a key enabling technology for harnessing more power from solar panels and enable plug and play operation. Power electronics for computer power supplies, communication equipment, and transportation have all targeted reliability and modularity as key requirements and have begun concerted efforts to replace monolithic components with collections of common smart modules. This is happening on several levels including (1) device level with intelligent control, (2) functional module level, and (3) system module. This same effort is needed in power electronics for solar applications. Development of modular units will result in standard power electronic converters that will have a lower installed and operating cost for the overall system. These units will lead to increased adaptability and flexibility of solar inverters. Incorporating autonomous fault current limiting and reconfiguration capabilities into the modules and having redundant modules will lead to a durable converter that can withstand the rigors of solar power generation for more than 30 years. Our vision for the technology roadmap is that there is no need for detailed design of new power converters for each new application or installation. One set of modules and controllers can be pre-developed and the only design question would be how many modules need to be in series or parallel for the specific power requirement. Then, a designer can put the modules together and add the intelligent reconfigurable controller. The controller determines how many modules are connected, but it might also ask for user input for the specific application during setup. The modules include protection against faults and can reset it, if necessary. In case of a power device failure, the controller reconfigures itself to continue limited operation until repair which might be as simple as taking the faulty module out and inserting a new module. The result is cost savings in design, maintenance, repair, and a grid that is more reliable and available. This concept would be a perfect fit for the recently announced funding opportunity announcement (DE-FOA-0000653) on Plug and Play Photovoltaics.

  18. Rheo-PIV of a shear-banding wormlike micellar solution under large amplitude oscillatory shear

    E-Print Network [OSTI]

    Dimitriou, Christopher J.

    We explore the behavior of a wormlike micellar solution under both steady and large amplitude oscillatory shear (LAOS) in a cone–plate geometry through simultaneous bulk rheometry and localized velocimetric measurements. ...

  19. Turbulent transport across shear layers in magnetically confined plasmas

    SciTech Connect (OSTI)

    Nold, B.; Ramisch, M. [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart, D-70569 Stuttgart (Germany); Manz, P.; Birkenmeier, G. [Physik-Department E28, Technische Universität München, James-Franck-Str.1, D-85748 Garching (Germany); Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Ribeiro, T. T.; Müller, H. W.; Scott, B. D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Fuchert, G. [IJL, Université de Lorraine, CNRS (UMR 7198), BP 40239 Vandoeuvre-lès-Nancy (France); Stroth, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Physik-Department E28, Technische Universität München, James-Franck-Str.1, D-85748 Garching (Germany)

    2014-10-15T23:59:59.000Z

    Shear layers modify the turbulence in diverse ways and do not only suppress it. A spatial-temporal investigation of gyrofluid simulations in comparison with experiments allows to identify further details of the transport process across shear layers. Blobs in and outside a shear layer merge, thereby exchange particles and heat and subsequently break up. Via this mechanism particles and heat are transported radially across shear layers. Turbulence spreading is the immanent mechanism behind this process.

  20. Spurious Shear in Weak Lensing with LSST

    SciTech Connect (OSTI)

    Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.

    2012-09-19T23:59:59.000Z

    The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

  1. STEEL PLATE SHEAR WALL BUILDINGS: DESIGN REQUIREMENTS AND RESEARCH

    E-Print Network [OSTI]

    Bruneau, Michel

    , University at Buffalo, Buffalo, NY 14260. #12;plate shear wall design and use of light-gage cold form platesSTEEL PLATE SHEAR WALL BUILDINGS: DESIGN REQUIREMENTS AND RESEARCH Michel Bruneau, P.E. 1 Dr areas. This paper provides an overview of the current state-of-the-art in steel plate shear wall design

  2. Reflective cracking of shear keys in multi-beam bridges

    E-Print Network [OSTI]

    Sharpe, Graeme Peter

    2009-06-02T23:59:59.000Z

    ..............................................2 Figure 2: PCI 33? Box Girder with Shear Keys................................................................5 Figure 3: TxDOT 34? Box Girder with Shear Keys .........................................................5 Figure 4: Test Specimen... Under Tension.........................................................................12 Figure 5: Test Specimen in Bending ...............................................................................12 Figure 6: Test Specimen in Shear...

  3. Elastic capsules in shear flow: Analytical solutions for constant and time-dependent shear rates

    E-Print Network [OSTI]

    Steffen Kessler; Reimar Finken; Udo Seifert

    2009-02-26T23:59:59.000Z

    We investigate the dynamics of microcapsules in linear shear flow within a reduced model with two degrees of freedom. In previous work for steady shear flow, the dynamic phases of this model, i.e. swinging, tumbling and intermittent behaviour, have been identified using numerical methods. In this paper, we integrate the equations of motion in the quasi-spherical limit analytically for time-constant and time-dependent shear flow using matched asymptotic expansions. Using this method, we find analytical expressions for the mean tumbling rate in general time-dependent shear flow. The capsule dynamics is studied in more detail when the inverse shear rate is harmonically modulated around a constant mean value for which a dynamic phase diagram is constructed. By a judicious choice of both modulation frequency and phase, tumbling motion can be induced even if the mean shear rate corresponds to the swinging regime. We derive expressions for the amplitude and width of the resonance peaks as a function of the modulation frequency.

  4. Reduction in transport by the parallel velocity shear instability due to reversed magnetic shear

    SciTech Connect (OSTI)

    McCarthy, D. R.; Fuselier, E. J.; Sen, S.

    2001-08-01T23:59:59.000Z

    A nonlocal theory of the electrostatic parallel velocity shear instability in a three-dimensional slab with a uniformly sheared magnetic field has been developed. It is shown that in the limit of a weak parallel velocity gradient, the linear growth rate can be increased depending upon the direction of the magnetic shear (s) with respect to the radial curvature of the parallel velocity profile (d{sup 2}v{sub {parallel}}/dx{sup 2}). When these parameters have the same sign, the growth rate can actually be stronger than in the limit of no magnetic shear. In this limit of increased instability, the eigenmode is broadened, thus producing enhanced transport. This effect should be observable when the scale length of the curvature is of order {approx}L{sub s}{rho}{sub s}. For strong parallel velocity gradients that are more typical of flows in tokamaks, the effect of the varying Doppler shift becomes more prominent on the stability of the mode, the net result being that the sensitivity of the growth rates on the sign of the magnetic shear becomes insignificant. This effect, however, is effectively offset when a finite density gradient is included. When the density scale length is of order the scale length of v{sub {parallel}}, the growth rate is moderately reduced, but becomes dependent again upon the sign of the magnetic shear.

  5. Design of series-parallel connected thermionic converter arrays

    SciTech Connect (OSTI)

    Mcvey, J.B.; Britt, E.J.; Fitzpatrick, G.O.; Dick, R.S.

    1981-01-01T23:59:59.000Z

    Applications of thermionic converters require that a large number of converters be connected together in a series-parallel array in order to provide a useful output voltage. Such an array also serves to insure a very high overall system reliability, despite possible failures of individual converters. This paper predicts the effects of a nonuniform distribution of input power on the performance of such an array. 9 refs.

  6. acid change converts: Topics by E-print Network

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

    Transmission, Distribution and Plants Websites Summary: converters can optimize the number of levels by using H bridges scaled in power of three. The shortcoming, the faulty...

  7. Sandia Energy - Sandia, NREL Release Wave Energy Converter Modeling...

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

    Sandia, NREL Release Wave Energy Converter Modeling and Simulation Code: WEC-Sim Home Renewable Energy Energy Water Power Partnership News News & Events Computational Modeling &...

  8. DOE Announces Webinars on the Wave Energy Converter Prize, the...

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

    24: Live Webinar on the Administration of the Wave Energy Converter Prize Funding Opportunity Announcement Webinar Sponsor: EERE Water Power Program The Energy Department will...

  9. Researchers hope better catalysts lead to better ways of converting...

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

    Researchers hope better catalysts lead to better ways of converting biomass to fuel By Jared Sagoff * August 7, 2013 Tweet EmailPrint ARGONNE, Ill. - Scientists and entrepreneurs...

  10. ac to dc converters: Topics by E-print Network

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

    to use solid state Inverters(DC to AC converters) to have a variable voltage, fixed or variable frequency power source available for industrial applications. With advancements...

  11. active npc converter: Topics by E-print Network

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

    Solid State Transformer Engineering Websites Summary: converters as distribution transformers 1. A power electronics-based solid state transformer (SST) providesAc-Ac Dual...

  12. alcohol angiotensin-converting-enzyme inhibitors: Topics by E...

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

    complications. There is no specific treatment for membranous nephropathy. Supportive care with the use of diuretics and angiotensin-converting enzyme inhibitors in combination...

  13. Integrated Solar Power Converters: Wafer-Level Sub-Module Integrated DC/DC Converter

    SciTech Connect (OSTI)

    None

    2012-02-09T23:59:59.000Z

    Solar ADEPT Project: CU-Boulder is developing advanced power conversion components that can be integrated into individual solar panels to improve energy yields. The solar energy that is absorbed and collected by a solar panel is converted into useable energy for the grid through an electronic component called an inverter. Many large, conventional solar energy systems use one, central inverter to convert energy. CU-Boulder is integrating smaller, microinverters into individual solar panels to improve the efficiency of energy collection. The University’s microinverters rely on electrical components that direct energy at high speeds and ensure that minimal energy is lost during the conversion process—improving the overall efficiency of the power conversion process. CU-Boulder is designing its power conversion devices for use on any type of solar panel.

  14. Effect of Shear Displacement Rate on the Internal Shear Strength of GCLs J. S. McCartney1

    E-Print Network [OSTI]

    Zornberg, Jorge G.

    shear strength of geosynthetic clay liners (GCLs) is to replicate behavior noted in the field. However a wider range of shear displacement rates. Introduction The internal shear strength of geosynthetic clay are prefabricated geocomposite materials used in hydraulic barriers as an alternative to compacted clay liners

  15. Direct measurement of shear properties of microfibers

    SciTech Connect (OSTI)

    Behlow, H.; Saini, D.; Durham, L.; Simpson, J.; Skove, M. J.; Rao, A. M. [Department of Physics and Astronomy, and Clemson Nanomaterials Center, Clemson University, Clemson, South Carolina 29634 (United States); Oliveira, L. [School of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634 (United States); Serkiz, S. M. [Department of Physics and Astronomy, and Clemson Nanomaterials Center, Clemson University, Clemson, South Carolina 29634 (United States); Savannah River National Laboratory, Aiken, South Carolina 29808 (United States)

    2014-09-15T23:59:59.000Z

    As novel fibers with enhanced mechanical properties continue to be synthesized and developed, the ability to easily and accurately characterize these materials becomes increasingly important. Here we present a design for an inexpensive tabletop instrument to measure shear modulus (G) and other longitudinal shear properties of a micrometer-sized monofilament fiber sample, such as nonlinearities and hysteresis. This automated system applies twist to the sample and measures the resulting torque using a sensitive optical detector that tracks a torsion reference. The accuracy of the instrument was verified by measuring G for high purity copper and tungsten fibers, for which G is well known. Two industrially important fibers, IM7 carbon fiber and Kevlar{sup ®} 119, were also characterized with this system and were found to have G = 16.5 ± 2.1 and 2.42 ± 0.32 GPa, respectively.

  16. Free energy of sheared colloidal glasses

    E-Print Network [OSTI]

    M. T. Dang; V. Chikkadi; R. Zargar; D. M. Miedema; D. Bonn; A. Zaccone; P. Schall

    2015-05-25T23:59:59.000Z

    We develop a free energy framework to describe the response of glasses to applied stress. Unlike crystals, for which the free energy increases quadratically with strain due to affine displacements, for glasses, the nonequilibrium free energy decreases due to complex interplay of non-affine displacements and dissipation. We measure this free energy directly in strained colloidal glasses, and use mean-field theory to relate it to affine and nonaffine displacements. Nonaffine displacements grow with applied shear due to shear-induced loss of structural connectivity. Our mean-field model allows for the first time to disentangle the complex contributions of affine and nonaffine displacements and dissipation in the transient deformation of glasses.

  17. Shear viscosity, cavitation and hydrodynamics at LHC

    E-Print Network [OSTI]

    Jitesh R. Bhatt; Hiranmaya Mishra; V. Sreekanth

    2011-09-28T23:59:59.000Z

    We study evolution of quark-gluon matter in the ultrarelativistic heavy-ion collisions within the frame work of relativistic second-order viscous hydrodynamics. In particular, by using the various prescriptions of a temperature-dependent shear viscosity to the entropy ratio, we show that the hydrodynamic description of the relativistic fluid become invalid due to the phenomenon of cavitation. For most of the initial conditions relevant for LHC, the cavitation sets in very early during the evolution of the hydrodynamics in time $\\lesssim 2 $fm/c. The cavitation in this case is entirely driven by the large values of shear viscosity. Moreover we also demonstrate that the conformal term used in equations of the relativistic dissipative hydrodynamic can influence the cavitation time.

  18. The effect of shear on neurodegeneration

    E-Print Network [OSTI]

    Triyoso, Dina Handayani

    1998-01-01T23:59:59.000Z

    and content by: I Theresa A. Good (Chair of Committee) Rayford G. Anthony (Member) Rita B. Moyes (Member) Michael V. Pishko (Member) Rayford G. Anthony (Head of Department) August 1998 Major Subject: Chemical Engineering ABSTRACT The Effect... of Shear on Neurodegeneration. (August 1998) Dina Handayani Triyoso, B. S. , Texas A&M University Chair of Advisory Committee: Dr. Theresa Good Glaucoma, hydrocephalus and head injury were characterized by elevated intraocular or intracranial pressure...

  19. Shear flow pumping in open microfluidic systems

    E-Print Network [OSTI]

    Markus Rauscher; S. Dietrich; Joel Koplik

    2006-10-26T23:59:59.000Z

    We propose to drive open microfluidic systems by shear in a covering fluid layer, e.g., oil covering water-filled chemical channels. The advantages as compared to other means of pumping are simpler forcing and prevention of evaporation of volatile components. We calculate the expected throughput for straight channels and show that devices can be built with off-the-shelf technology. Molecular dynamics simulations suggest that this concept is scalable down to the nanoscale.

  20. Shear viscosity of hadronic gas mixtures

    E-Print Network [OSTI]

    K. Itakura; O. Morimatsu; H. Otomo

    2008-05-12T23:59:59.000Z

    We investigate the effects of baryon chemical potential \\mu on the shear viscosity coefficient \\eta and the viscosity to entropy density ratio \\eta/s of a pion-nucleon gas mixture. We find that \\eta is an increasing function of T and \\mu, while the ratio \\eta/s turns to a decreasing function in a wide region of T-\\mu plane. In the kinematical region we studied, the smallest value of \\eta/s is about 0.3.

  1. Shear viscosity and out of equilibrium dynamics

    E-Print Network [OSTI]

    Andrej El; Zhe Xu; Carsten Greiner; Azwinndini Muronga

    2009-06-18T23:59:59.000Z

    Using Grad's method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio $\\eta/s$ are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with $\\eta/s$ obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling $\\alpha_s \\sim 0.3$(with $\\eta/s\\approx 0.18$) and is a factor of 2-3 larger at a small coupling $\\alpha_s \\sim 0.01$. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on $\\eta/s$, except when employing a small $\\alpha_s$. On the other hand, we demonstrate that for such small $\\alpha_s$, the gluon system is far from kinetic and chemical equilibrium, which indicates the break down of second-order hydrodynamics because of the strong noneqilibrium evolution. In addition, for large $\\alpha_s$ ($0.3-0.6$), the Israel-Stewart hydrodynamics formally breaks down at large momentum $p_T\\gtrsim 3$ GeV but is still a reasonably good approximation.

  2. Way to reduce arc voltage losses in hybrid thermionic converters

    SciTech Connect (OSTI)

    Tskhakaya, V.K.; Yarygin, V.I.

    1982-03-01T23:59:59.000Z

    Experimental results are reported concerning the output and emission characteristics of the arc and hybrid regimes in a plane-parallel thermionic converter with Pt--Zr--O electrode pair. It is shown that arc voltage losses can be reduced to values below those obtainable in ordinary arc thermionic converters.

  3. Optimizing Ballast Design of Wave Energy Converters Using Evolutionary Algorithms

    E-Print Network [OSTI]

    Tumer, Kagan

    Optimizing Ballast Design of Wave Energy Converters Using Evolutionary Algorithms Mitch Colby, 97331 kagan.tumer@oregonstate.edu ABSTRACT Wave energy converters promise to be a viable alternative the ballast geometry of a wave energy genera- tor using a two step process. First, we generate a function

  4. Drive System for Traction Applications Using 81-Level Converter

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Católica de Chile)

    of frequency converter. Keywords: vehicle power electronics, vehicle motor drives. I. INTRODUCTION Power Electronics technologies contribute with important part in the development of electric vehicles. On the otherDrive System for Traction Applications Using 81-Level Converter Juan W. Dixon, Micah E. Ortúzar

  5. Ability of Catalytic Converters to Reduce Air Pollution

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    NOx - 1 Ability of Catalytic Converters to Reduce Air Pollution MEASUREMENT OF SELECTED AIR POLLUTANTS IN CAR EXHAUST Last updated: June 17, 2014 #12;NOx - 2 Ability of Catalytic Converters to Reduce Air Pollution MEASUREMENT OF SELECTED AIR POLLUTANTS IN CAR EXHAUST INTRODUCTION Automobile engines

  6. ORIGINAL PAPER Antioxidant and angiotensin-converting enzyme inhibitory

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    functions of these peptides derived from milk proteins are antioxidant and angiotensin-converting enzyme antioxidant activities of the peptides have been observed as chelation of transition metals and scavengingORIGINAL PAPER Antioxidant and angiotensin-converting enzyme inhibitory activity of yoghurt

  7. The frequency dependent impedance of an HVdc converter

    SciTech Connect (OSTI)

    Wood, A.R.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand)

    1995-07-01T23:59:59.000Z

    A linear and direct method of determining the frequency dependent impedance of a 12 pulse HVdc converter is presented. Terms are developed for both the dc and ac side impedances of the converter, including the effect of the firing angle control system, the commutation period, and the variability of the commutation period. The impedance predictions are verified by dynamic simulation.

  8. A study of Schwarz converters for nuclear powered spacecraft

    SciTech Connect (OSTI)

    Stuart, T.A. [Univ. of Toledo, OH (United States); Schwarze, G.E. [Lewis Research Center, Cleveland, OH (United States)

    1994-09-01T23:59:59.000Z

    High power space systems which use low dc voltage, high current sources such as thermoelectric generators, will most likely require high voltage conversion for transmission purposes. This study considers the use of the Schwarz resonant converter for use as the basic building block to accomplish this low-to-high voltage conversion for either a dc or an ac spacecraft bus. The Schwarz converter has the important assets of both inherent fault tolerance and resonant operation and parallel operation in modular form is possible. A regulated dc spacecraft bus requires only a single stage converter while a constant frequency ac bus requires a cascaded Schwarz converter configuration. If the power system requires constant output power from the dc generator, then a second converter is required to route unneeded power to a ballast load.

  9. A computer program for HVDC converter station RF noise calculations

    SciTech Connect (OSTI)

    Kasten, D.G.; Caldecott, R.; Sebo, S.A. (Ohio State Univ., Columbus, OH (United States). Dept. of Electrical Engineering); Liu, Y. (Virginia Polytechnic Inst. State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering)

    1994-04-01T23:59:59.000Z

    HVDC converter station operations generate radio frequency (RF) electromagnetic (EM) noise which could interfere with adjacent communication and computer equipment, and carrier system operations. A generic Radio Frequency Computer Analysis Program (RAFCAP) for calculating the EM noise generated by valve ignition of a converter station has been developed as part of a larger project. The program calculates RF voltages, currents, complex power, ground level electric field strength and magnetic flux density in and around an HVDC converter station. The program requires the converter station network to be represented by frequency dependent impedance functions. Comparisons of calculated and measured values are given for an actual HVDC station to illustrate the validity of the program. RAFCAP is designed to be used by engineers for the purpose of calculating the RF noise produced by the igniting of HVDC converter valves.

  10. Wind turbines convert the kinetic energy in moving air into rotational energy, which in turn is converted

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    Wind turbines convert the kinetic energy in moving air into rotational energy, which in turn is converted to electricity. Since wind speeds vary from month to month and second to second, the amount of electricity wind can make varies constantly. Sometimes a wind turbine will make no power at all

  11. Magnet Technology for Power Converters: Nanocomposite Magnet Technology for High Frequency MW-Scale Power Converters

    SciTech Connect (OSTI)

    None

    2012-02-27T23:59:59.000Z

    Solar ADEPT Project: CMU is developing a new nanoscale magnetic material that will reduce the size, weight, and cost of utility-scale PV solar power conversion systems that connect directly to the grid. Power converters are required to turn the energy that solar power systems create into useable energy for the grid. The power conversion systems made with CMU’s nanoscale magnetic material have the potential to be 150 times lighter and significantly smaller than conventional power conversion systems that produce similar amounts of power.

  12. Hysteresis and Lubrication in Shear Thickening of Cornstarch Suspensions

    E-Print Network [OSTI]

    Clarence E. Chu; Joel A. Groman; Hannah L. Sieber; James G. Miller; Ruth J. Okamoto; Jonathan I. Katz

    2014-05-28T23:59:59.000Z

    Aqueous and brine suspensions of corn starch show striking discontinuous shear thickening. We have found that a suspension shear-thickened throughout may remain in the jammed thickened state as the strain rate is reduced, but an unjamming front may propagate from any unjammed regions. Transient shear thickening is observed at strain rates below the thickening threshold, and above it the stress fluctuates. The jammed shear-thickened state may persist to low strain rates, with stresses resembling sliding friction and effective viscosity inversely proportional to the strain rate. At the thickening threshold fluid pressure depins the suspension's contact lines on solid boundaries so that it slides, shears, dilates and jams. In oil suspensions lubrication and complete wetting of confining surfaces eliminate contact line forces and prevent jamming and shear thickening, as does addition of immiscible liquid surfactant to brine suspensions. Starch suspensions in glycerin-water solutions, viscous but incompletely wetting, have intermediate properties.

  13. Ion trapping in the emitter sheath in thermionic converters

    SciTech Connect (OSTI)

    Lundgren, L.

    1985-12-01T23:59:59.000Z

    The effect of ion trapping in the emitter sheath in ignited thermionic converters is studied. The ion trapping prevents the emitter-sheath barrier from being higher than approximately 0.1 eV, when the current decreases in the converter. This gives a condition for the constriction of the arc. I-V curves are calculated for an ignited thermionic converter with a hydrodynamic plasma theory that takes into account the effect of Coulomb scattering and volume recombination, but assumes that the electron temperature is constant in the plasma.

  14. Design and operation of a thermionic converter in air

    SciTech Connect (OSTI)

    Horner, M.H.; Begg, L.L.; Smith, J.N. Jr. [General Atomics, San Diego, CA (United States); Geller, C.B.; Kallnowski, J.E. [Westinghouse Electric Corp., West Mifflin, PA (United States). Bettis Atomic Power Lab.

    1995-01-01T23:59:59.000Z

    An electrically heated thermionic converter has been designed, built and successfully tested in air. Several unique features were incorporated in this converter: an integral cesium reservoir, innovative ceramic-to-metal seals, a heat rejection system coupling the collector to a low temperature heat sink and an innovative cylindrical heater filament. The converter was operated for extended periods of time with the emitter at about 1900 K. the collector at about 700 K, and a power density of over 2 w(e)/sq. cm. Input power transients were run between 50% and 100% thermal power, at up to 1% per second, without instabilities in performance.

  15. Prediction of core saturation instability at an HVDC converter

    SciTech Connect (OSTI)

    Burton, R.S. [Teshmont Consultants, Inc., Winnipeg, Manitoba (Canada)] [Teshmont Consultants, Inc., Winnipeg, Manitoba (Canada); Fuchshuber, C.F. [Alberta Power Ltd., Edmonton, Alberta (Canada)] [Alberta Power Ltd., Edmonton, Alberta (Canada); Woodford, D.A. [Manitoba HVDC Research Centre, Winnipeg, Manitoba (Canada)] [Manitoba HVDC Research Centre, Winnipeg, Manitoba (Canada); Gole, A.M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada)] [Univ. of Manitoba, Winnipeg, Manitoba (Canada)

    1996-10-01T23:59:59.000Z

    Core saturation instability has occurred on several HVDC schemes resulting from interactions between second harmonic and dc quantities (voltages and currents) on the ac side of the converter and fundamental frequency quantities on the dc side of the converter. The instability can be reinforced by unbalanced saturation of the converter transformers. The paper presents an analytical method which can be used to quickly screen ac and dc system operating conditions to predict where core saturation instability is likely to occur. Analytical results have been confirmed using the digital transients simulation program PSCAD/EMTDC.

  16. Shear viscosity and spectral function of the quark matter

    E-Print Network [OSTI]

    Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome

    2006-06-19T23:59:59.000Z

    We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density.

  17. Criticality and Scaling Relations in a Sheared Granular Material

    E-Print Network [OSTI]

    Takahiro Hatano; Michio Otsuki; Shin-ichi Sasa

    2006-09-09T23:59:59.000Z

    We investigate a rheological property of a dense granular material under shear. By a numerical experiment of the system with constant volume, we find a critical volume fraction at which the shear stress and the pressure behave as power-law functions of the shear strain rate. We also present a simple scaling argument that determines the power-law exponents. Using these results, we interpret a power-law behavior observed in the system under constant pressure.

  18. Shear viscosity of $?$-stable nuclear matter

    E-Print Network [OSTI]

    Omar Benhar; Arianna Carbone

    2009-12-01T23:59:59.000Z

    Viscosity plays a critical role in determining the stability of rotating neutron stars. We report the results of a calculation of the shear viscosity of $\\beta$~-~stable matter, carried out using an effective interaction based on a state-of-the-art nucleon-nucleon potential and the formalism of correlated basis functions. Within our approach the equation of state, determining the proton fraction, and the nucleon-nucleon scattering probability are consistently obtained from the same dynamical model. The results show that, while the neutron contribution to the viscosity is always dominant, above nuclear saturation density the electron contribution becomes appreciable.

  19. Critical shear stresses in cohesive soils 

    E-Print Network [OSTI]

    Rektorik, Robert James

    1964-01-01T23:59:59.000Z

    provided by Dr. E. T. Smerdon l during the course of this study and also to express my appreciation to Mr. J. W. Sorenson, Mr. R. E. Schiller, Jr. , and Dr. 7. D. Williams for the assistance provided in the preparation of this report. I also wish... . where 11 w = angular velocity 2 M = 2n (R ) ht = torque on the inner cylinder 1 h = height of the inner cylinder dynamic viscosity R = radius of inner cylinder 1 R = radius of inner face of the outer cylinder 2 t = boundary shear FL FTL FL...

  20. Dynamics of flexible fibers in shear flow

    E-Print Network [OSTI]

    Agnieszka M. Slowicka; Eligiusz Wajnryb; Maria L. Ekiel-Jezewska

    2015-04-03T23:59:59.000Z

    Dynamics of flexible non-Brownian fibers in shear flow at low-Reynolds-number are analyzed numerically for a wide range of the ratios A of the fiber bending force to the viscous drag force. Initially, the fibers are aligned with the flow, and later they move in the plane perpendicular to the flow vorticity. A surprisingly rich spectrum of different modes is observed when the value of A is systematically changed, with sharp transitions between coiled and straightening out modes, period-doubling bifurcations from periodic to migrating solutions, irregular dynamics and chaos.

  1. Shear Jamming in Granular Experiments without Basal Friction

    E-Print Network [OSTI]

    Hu Zheng; Joshua A. Dijksman; Robert P. Behringer

    2014-08-08T23:59:59.000Z

    Jammed states of frictional granular systems can be induced by shear strain at densities below the isostatic jamming density ($\\phi_c$). It remains unclear, however, how much friction affects this so-called shear-jamming. Friction appears in two ways in this type of experiment: friction between particles, and friction between particles and the base on which they rest. Here, we study how particle-bottom friction, or basal friction, affects shear jamming in quasi-two dimensional experiments. In order to study this issue experimentally, we apply simple shear to a disordered packing of photoelastic disks. We can tune the basal friction of the particles by immersing the particles in a density matched liquid, thus removing the normal force, hence the friction, between the particles and base. We record the overall shear stress, and particle motion, and the photoelastic response of the particles. We compare the shear response of dry and immersed samples, which enables us to determine how basal friction affects shear jamming. Our findings indicate that changing the basal friction shifts the point of shear jamming, but it does not change the basic phenomenon of shear jamming.

  2. Anomalous shear wave attenuation in the shallow crust beneath...

    Open Energy Info (EERE)

    Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal...

  3. azeite transtensional shear: Topics by E-print Network

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

    in a landfill cap or base liner systemi Internal and Interface Shear Strength of Geosynthetic Clay Liners (GCLs) by John Scott Mc Strength of Geosynthetic Clay Liners (GCLs)...

  4. Idaho Application for Permit to Convert a Geothermal Injection...

    Open Energy Info (EERE)

    navigation, search OpenEI Reference LibraryAdd to library Form: Idaho Application for Permit to Convert a Geothermal Injection Well - Form 4003-3 Form Type ApplicationNotice Form...

  5. Multilevel Converter Topologies for Utility Scale Solar Photovoltaic Power Systems

    E-Print Network [OSTI]

    Essakiappan, Somasundaram

    2014-04-30T23:59:59.000Z

    sources like photovoltaics (PV) to the utility grid, some of which are multilevel topologies. Multilevel topologies allow for use of lower voltage semiconductor devices than two-level converters. They also produce lower distortion output voltage waveforms...

  6. Oversampled pipline A/D converters with mismatch shaping

    E-Print Network [OSTI]

    Shabra, Ayman U. (Ayman Umar)

    2001-01-01T23:59:59.000Z

    This thesis introduces a technique to improve the linearity of pipeline analog to digital converters (ADC). Through a combination of oversampling and mismatch shaping, the distortion introduced by component mismatch is ...

  7. Protocols for the Equitable Assessment of Marine Energy Converters 

    E-Print Network [OSTI]

    Ingram, David; Smith, George; Bittencourt-Ferreira, Claudio; Smith, Helen

    This book contains the suite of protocols for the equitable evaluation of marine energy converters (based on either tidal or wave energy) produced by the EquiMar consortium led by the University of Edinburgh. These protocols ...

  8. Monolithic series-connected gallium arsenide converter development

    SciTech Connect (OSTI)

    Spitzer, M.B.; McClelland, R.W.; Dingle, B.D.; Dingle, J.E.; Hill, D.S. (Kopin Corp., Taunton, MA (United States)); Rose, B.H. (Sandia National Labs., Albuquerque, NM (United States))

    1991-01-01T23:59:59.000Z

    We report the development of monolithic GaAs photovoltaic devices intended to convert light generated by a laser or other bright source to electricity. The converters described here can provide higher operating voltage than is possible using a single-junction converter, owing to use of a monolithic circuit that forms a planar series-connected string of single-junction sub-cells. This planar monolithic circuit is arranged to deliver the desired voltage and current during operation at the maximum power point. The paper describes two-, six-, and twelve-junction converters intended for illumination by a laser diode with a wavelength of 0.8 {mu}m. Design and characterization data are presented for optical power in the range of 100 mW to 1 W. The best conversion efficiency exceeds 50%. 9 refs., 4 figs., 2 tabs.

  9. Automated Synthesis Tool for Design Optimization of Power Electronic Converters

    E-Print Network [OSTI]

    Mirjafari, Mehran

    2013-01-09T23:59:59.000Z

    Designers of power electronic converters usually face the challenge of having multiple performance indices that must be simultaneously optimized, such as maximizing efficiency while minimizing mass or maximizing reliability while minimizing cost...

  10. Sandia National Laboratories: resonant wave-energy converter...

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

    resonant wave-energy converter devices Inter-Agency Agreement Signed between DOE's Wind and Water Power Program and Carderock On December 3, 2014, in Energy, News, News & Events,...

  11. Photo of the Week: Converting Solar Energy into Fuel | Department...

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

    toured the facilities that produce wind power generators and converters, in addition to PV solar inverters. In this photo he looks at a Stator 2MW Wind Turbine Generator. | Photo...

  12. Multiport Converter Topologies for Distributed Energy System Applications

    E-Print Network [OSTI]

    Hawke, Joshua

    2014-07-28T23:59:59.000Z

    fuel cell hybrid energy storage (MFC+HES) converter. First, low-voltage and medium-voltage PSC architectures are shown to decouple series-connected source currents and enable independent control. Multidimensional modeling and analysis is then discussed...

  13. A global maximum power point tracking DC-DC converter

    E-Print Network [OSTI]

    Duncan, Joseph, 1981-

    2005-01-01T23:59:59.000Z

    This thesis describes the design, and validation of a maximum power point tracking DC-DC converter capable of following the true global maximum power point in the presence of other local maximum. It does this without the ...

  14. MATHEMATICAL ANALYSIS OF A WAVE ENERGY CONVERTER ARNAUD ROUGIREL

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    for buoy-type ocean wave energy converter. The simplest model for this scheme is a non autonomous piecewise): see [OOS10]. Basically, a WEC is a floating body with a power takeoff system. It uses the vertical

  15. Method for converting uranium oxides to uranium metal

    DOE Patents [OSTI]

    Duerksen, Walter K. (Norris, TN)

    1988-01-01T23:59:59.000Z

    A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

  16. A Dual Supply Buck Converter with Improved Light Load Efficiency 

    E-Print Network [OSTI]

    Chen, Hui

    2013-05-02T23:59:59.000Z

    Power consumption is the primary concern in battery-operated portable applications. Buck converters have gained popularity in powering portable devices due to their compact size, good current delivery capability and high efficiency. However...

  17. Development, evaluation, and design applications of an AMTEC converter model 

    E-Print Network [OSTI]

    Spence, Cliff Alan

    2002-01-01T23:59:59.000Z

    An AMTEC converter model was developed and its effectiveness as a design tool was evaluated. To develop the model, requirements of the model were defined, modeling equations were selected, and a methodology for model development was established...

  18. Vehicle Technologies Office Merit Review 2014: WBG Converters and Chargers

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about WBG converters...

  19. Non-synchronous control of self-oscillating resonant converters

    DOE Patents [OSTI]

    Glaser, John Stanley (Niskayuna, NY); Zane, Regan Andrew (Scotia, NY)

    2002-01-01T23:59:59.000Z

    A self-oscillating switching power converter has a controllable reactance including an active device connected to a reactive element, wherein the effective reactance of the reactance and the active device is controlled such that the control waveform for the active device is binary digital and is not synchronized with the switching converter output frequency. The active device is turned completely on and off at a frequency that is substantially greater than the maximum frequency imposed on the output terminals of the active device. The effect is to vary the average resistance across the active device output terminals, and thus the effective output reactance, thereby providing converter output control, while maintaining the response speed of the converter.

  20. Randomized modulation of power converters via Markov chains

    E-Print Network [OSTI]

    Stankovic, Aleksandar M.

    Randomized modulation of switching in power converters holds promise for reducing filtering requirements and reducing acoustic noise in motor drive applications. This paper is devoted to issues in analysis and synthesis ...

  1. A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical Parameters

    E-Print Network [OSTI]

    Victoria, University of

    A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical of Mechanical Engineering) ABSTRACT Within a wave energy converter's operational bandwidth, device operation

  2. An evaluation of a parallel-resonant current-source converter for an electrothermal thruster

    E-Print Network [OSTI]

    Tchamdjou, Aristide-Marie

    1996-01-01T23:59:59.000Z

    The Parallel-Resonant Current-Source Converter promises highly efficient DCDC power conversion. It uses zero-voltage switching to reduce the losses and improve the converter efficiency. The Parallel-Resonant Current-Source Converter has been...

  3. An evaluation of a parallel-resonant current-source converter for an electrothermal thruster 

    E-Print Network [OSTI]

    Tchamdjou, Aristide-Marie

    1996-01-01T23:59:59.000Z

    The Parallel-Resonant Current-Source Converter promises highly efficient DCDC power conversion. It uses zero-voltage switching to reduce the losses and improve the converter efficiency. The Parallel-Resonant Current-Source Converter has been...

  4. Bi-directional Current-fed Medium Frequency Transformer Isolated AC-DC Converter 

    E-Print Network [OSTI]

    Essakiappan, Somasundaram

    2011-08-08T23:59:59.000Z

    The use of high power converters has increased tremendously. Increased demand for transportation, housing and industrial needs means that more number of power converters interact with the utility power grid. These converters are non...

  5. Analysis and design of matrix converters for adjustable speed drives and distributed power sources 

    E-Print Network [OSTI]

    Cha, Han Ju

    2004-11-15T23:59:59.000Z

    Recently, matrix converter has received considerable interest as a viable alternative to the conventional back-to-back PWM (Pulse Width Modulation) converter in the ac/ac conversion. This direct ac/ac converter provides some attractive...

  6. Shear Viscosity in a CFL Quark Star

    E-Print Network [OSTI]

    Cristina Manuel; Antonio Dobado; Felipe J. Llanes-Estrada

    2005-09-30T23:59:59.000Z

    We compute the mean free path and shear viscosity in the color-flavor locked (CFL) phase of dense quark matter at low temperature T, when the contributions of mesons, quarks and gluons to the transport coefficients are Boltzmann suppressed. CFL quark matter displays superfluid properties, and transport phenomena in such cold regime are dominated by phonon-phonon scattering. We study superfluid phonons within thermal field theory and compute the mean free path associated to their most relevant collision processes. Small-angle processes turn out to be more efficient in slowing transport phenomena in the CFL matter, while the mean free path relevant for the shear viscosity is less sensitive to collinear scattering due to the presence of zero modes in the Boltzmann equation. In analogy with superfluid He4, we find the same T power law for the superfluid phonon damping rate and mean free path. Our results are relevant for the study of rotational properties of compact stars, and correct wrong estimates existing in the literature.

  7. Shear viscosity in neutron star cores

    E-Print Network [OSTI]

    P. S. Shternin; D. G. Yakovlev

    2008-08-21T23:59:59.000Z

    We calculate the shear viscosity $\\eta = \\eta_{e\\mu}+\\eta_{n}$ in a neutron star core composed of nucleons, electrons and muons ($\\eta_{e\\mu}$ being the electron-muon viscosity, mediated by collisions of electrons and muons with charged particles, and $\\eta_{n}$ the neutron viscosity, mediated by neutron-neutron and neutron-proton collisions). Deriving $\\eta_{e\\mu}$, we take into account the Landau damping in collisions of electrons and muons with charged particles via the exchange of transverse plasmons. It lowers $\\eta_{e\\mu}$ and leads to the non-standard temperature behavior $\\eta_{e\\mu}\\propto T^{-5/3}$. The viscosity $\\eta_{n}$ is calculated taking into account that in-medium effects modify nucleon effective masses in dense matter. Both viscosities, $\\eta_{e\\mu}$ and $\\eta_{n}$, can be important, and both are calculated including the effects of proton superfluidity. They are presented in the form valid for any equation of state of nucleon dense matter. We analyze the density and temperature dependence of $\\eta$ for different equations of state in neutron star cores, and compare $\\eta$ with the bulk viscosity in the core and with the shear viscosity in the crust.

  8. Dual-domain lateral shearing interferometer

    DOE Patents [OSTI]

    Naulleau, Patrick P.; Goldberg, Kenneth Alan

    2004-03-16T23:59:59.000Z

    The phase-shifting point diffraction interferometer (PS/PDI) was developed to address the problem of at-wavelength metrology of extreme ultraviolet (EUV) optical systems. Although extremely accurate, the fact that the PS/PDI is limited to use with coherent EUV sources, such as undulator radiation, is a drawback for its widespread use. An alternative to the PS/PDI, with relaxed coherence requirements, is lateral shearing interferometry (LSI). The use of a cross-grating, carrier-frequency configuration to characterize a large-field 4.times.-reduction EUV lithography optic is demonstrated. The results obtained are directly compared with PS/PDI measurements. A defocused implementation of the lateral shearing interferometer in which an image-plane filter allows both phase-shifting and Fourier wavefront recovery. The two wavefront recovery methods can be combined in a dual-domain technique providing suppression of noise added by self-interference of high-frequency components in the test-optic wavefront.

  9. Shear strength of reinforced geosynthetic clay liner

    SciTech Connect (OSTI)

    Gilbert, R.B. [Univ. of Texas, Austin, TX (United States)] [Univ. of Texas, Austin, TX (United States); Fernandez, F. [Golder Associates, Inc., Naperville, IL (United States)] [Golder Associates, Inc., Naperville, IL (United States); Horsfield, D.W. [Golder Associates, Ltd., Calgary, Alberta (Canada)] [Golder Associates, Ltd., Calgary, Alberta (Canada)

    1996-04-01T23:59:59.000Z

    Direct shear tests are conducted to evaluate the internal strength of a reinforced geosynthetic clay liner (GCL) at normal stresses between 3.45 and 69.0 kPa. The polypropylene reinforcement increases the peak internal strength compared to that reported in the literature for unreinforced GCLs; however, the reinforced GCL exhibits a postpeak reduction in strength with displacement due to failure of the reinforcement. Direct shear tests are also conducted to evaluate the interface strength between the reinforced GCL and other geosynthetic materials. Extrusion of bentonite from the GCL into the interfaces is noticed and may reduce the interface strengths. Peak interface strengths between the GCL and a smooth geomembrane or a drainage geocomposite are less than the internal strength at all normal stresses tested. However, the peak interface strength between the GCL and a textured geomembrane is limited by the peak internal strength for normal stresses exceeding 13.8 kPa. Postpeak reductions in strength with displacement occur for this interface at these higher normal stresses due to reinforcement failure.

  10. Formation of double-valued sheaths in thermionic converters

    SciTech Connect (OSTI)

    Lundgren, L.

    1983-08-01T23:59:59.000Z

    A theory for the sheath in an ignited thermionic converter is presented. The theory includes the effect of the velocity spread of the particles but the charge-particle collisions are neglected. Conditions for the appearance of a virtual emitter are given. The theory is compared with a beam approximation theory and a hydrodynamic theory. All three theories give almost the same condition for the appearance of a virtual emitter in an ignited thermionic converter.

  11. Bi-directional power control system for voltage converter

    DOE Patents [OSTI]

    Garrigan, N.R.; King, R.D.; Schwartz, J.E.

    1999-05-11T23:59:59.000Z

    A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals. 10 figs.

  12. Bi-directional power control system for voltage converter

    DOE Patents [OSTI]

    Garrigan, Neil Richard (Niskayuna, NY); King, Robert Dean (Schenectady, NY); Schwartz, James Edward (Slingerlands, NY)

    1999-01-01T23:59:59.000Z

    A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals.

  13. angiotensin-i converting enzyme: Topics by E-print Network

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

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  14. ac-dc-ac z-source converter: Topics by E-print Network

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

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  15. DOE-TSPP-8-2013, Converting DOE Technical Standards to Voluntary...

    Energy Savers [EERE]

    8-2013, Converting DOE Technical Standards to Voluntary Consensus Standards DOE-TSPP-8-2013, Converting DOE Technical Standards to Voluntary Consensus Standards Technical Standards...

  16. Shear-Induced Degradation of Linear Polyacrylamide Solutions during

    E-Print Network [OSTI]

    Shear-Induced Degradation of Linear Polyacrylamide Solutions during Pre-Electrophoretic Loading to minimize shear-induced degradation of the polymer molecules. Currently, the community lacks quan- titative data with which to gauge the range of flow rates that prevent polymer degradation. In this study

  17. Modeling of strain rate effects on clay in simple shear

    E-Print Network [OSTI]

    Jung, Byoung Chan

    2006-08-16T23:59:59.000Z

    of strain rate on clays in simple shear conditions. The response of clay soils is highly dependent on the rate of strain for both effective stress path and stress-strain behavior. The undrained shear strength is strongly influenced by strain rate both...

  18. Large amplitude oscillatory shear of pseudoplastic and elastoviscoplastic materials

    E-Print Network [OSTI]

    , Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 2 Halliburton amplitude oscillatory shear. A new parameter, the perfect plastic dissipation ratio, is introduced, a pseudoplastic shear-thinning xanthan gum solution and an elastoviscoplastic invert-emulsion drilling fluid

  19. Adjuvant Radiotherapy for Gastric Cancer: A Dosimetric Comparison of 3-Dimensional Conformal Radiotherapy, Tomotherapy (registered) and Conventional Intensity Modulated Radiotherapy Treatment Plans

    SciTech Connect (OSTI)

    Dahele, Max [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Skinner, Matthew; Schultz, Brenda; Cardoso, Marlene; Bell, Chris [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Ung, Yee C. [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)], E-mail: yee.ung@sunnybrook.ca

    2010-07-01T23:59:59.000Z

    Some patients with gastric cancer benefit from post-operative chemo-radiotherapy, but adequately irradiating the planning target volume (PTV) whilst avoiding organs at risk (OAR) can be difficult. We evaluate 3-dimensional conformal radiotherapy (CRT), conventional intensity-modulated radiotherapy (IMRT) and helical tomotherapy (TT). TT, 2 and 5-field (F) CRT and IMRT treatment plans with the same PTV coverage were generated for 5 patients and compared. Median values are reported. The volume of left/right kidney receiving at least 20Gy (V20) was 57/51% and 51/60% for 2 and 5F-CRT, and 28/14% for TT and 27/19% for IMRT. The volume of liver receiving at least 30Gy (V30) was 45% and 62% for 2 and 5F-CRT, and 37% for TT and 35% for IMRT. With TT, 98% of the PTV received 95-105% of the prescribed dose, compared with 45%, 34% and 28% for 2F-CRT, 5F-CRT and IMRT respectively. Using conventional metrics, conventional IMRT can achieve comparable PTV coverage and OAR sparing to TT, but at the expense of PTV dose heterogeneity. Both irradiate large volumes of normal tissue to low doses. Additional studies are needed to demonstrate the clinical impact of these technologies.

  20. Density waves in the shearing sheet I. Swing amplification

    E-Print Network [OSTI]

    B. Fuchs

    2001-03-02T23:59:59.000Z

    The shearing sheet model of a galactic disk is studied anew. The theoretical description of its dynamics is based on three building blocks: Stellar orbits, which are described here in epicyclic approximation, the collisionless Boltzmann equation determining the distribution function of stars in phase space, and the Poisson equation in order to take account of the self-gravity of the disk. Using these tools I develop a new formalism to describe perturbations of the shearing sheet. Applying this to the unbounded shearing sheet model I demonstrate again how the disturbances of the disk evolve always into `swing amplified' density waves, i.e. spiral-arm like, shearing density enhancements, which grow and decay while the wave crests swing by from leading to trailing orientation. Several examples are given how such `swing amplification' events are incited in the shearing sheet.

  1. Spatially localized solutions of shear flows

    E-Print Network [OSTI]

    Gibson, J F

    2013-01-01T23:59:59.000Z

    We present several new spatially localized equilibrium and traveling-wave solutions of plane Couette and channel flows. The solutions exhibit strikingly concentrated regions of vorticity that are flanked on either side by high-speed streaks. For several traveling-wave solutions of channel flow, the concentrated vortex structures are confined to the near-wall region and form particularly isolated and elemental coherent structures in the near-wall region of shear flows. The solutions are constructed by a variety of methods: application of windowing functions to previously known spatially periodic solutions, continuation from plane Couette to channel flow conditions, and from initial guesses obtained from turbulent simulation data. We show how the symmetries of localized solutions derive from the symmetries of their periodic counterparts, analyze the exponential decay of their tails, examine the scale separation and scaling of their streamwise Fourier modes, and show that they develop critical layers for large R...

  2. The SDSS Coadd: Cosmic Shear Measurement

    SciTech Connect (OSTI)

    Lin, Huan; /Fermilab; Dodelson, Scott; /Fermilab /Chicago U., EFI /Chicago U., KICP; Seo, Hee-Jong; /UC, Berkeley; Soares-Santos, Marcelle; /Fermilab; Annis, James; /Fermilab; Hao, Jiangang; /Fermilab; Johnston, David; /Fermilab; Kubo, Jeffrey M.; /Fermilab; Reis, Ribamar R.R.; /Fermilab /Rio de Janeiro Federal U.; Simet, Melanie; /Chicago U., EFI /Chicago U., KICP

    2011-11-01T23:59:59.000Z

    Stripe 82 in the Sloan Digital Sky Survey was observed multiple times, allowing deeper images to be constructed by coadding the data. Here we analyze the ellipticities of background galaxies in this 275 square degree region, searching for evidence of distortions due to cosmic shear. The E-mode is detected in both real and Fourier space with > 5-{sigma} significance on degree scales, while the B-mode is consistent with zero as expected. The amplitude of the signal constrains the combination of the matter density {Omega}{sub m} and fluctuation amplitude {sigma}{sub 8} to be {Omega}{sub m}{sup 0.7} {sigma}{sub 8} = 0.276{sub -0.050}{sup +0.036}.

  3. Jet momentum balance independent of shear viscosity

    E-Print Network [OSTI]

    R. B. Neufeld

    2012-02-24T23:59:59.000Z

    Jet momentum balance measurements, such as those recently performed by the CMS collaboration, provide an opportunity to quantify the energy transferred from a parton shower to the underlying medium in heavy-ion collisions. Specifically, I argue that the Cooper-Frye freezeout distribution associated with the energy and momentum deposited by the parton shower is controlled to a significant extent by the distribution of the underlying bulk matter and independent of the details of how deposited energy is redistributed in the medium, which is largely determined by transport coefficients such as shear viscosity. Thus by matching the distribution of momentum associated with the secondary jet in such measurements to the thermal distribution of the underlying medium, one can obtain a model independent estimate on the amount of parton shower energy deposited.

  4. Adjustable shear stress erosion and transport flume

    DOE Patents [OSTI]

    Roberts, Jesse D. (Carlsbad, NM); Jepsen, Richard A. (Carlsbad, NM)

    2002-01-01T23:59:59.000Z

    A method and apparatus for measuring the total erosion rate and downstream transport of suspended and bedload sediments using an adjustable shear stress erosion and transport (ASSET) flume with a variable-depth sediment core sample. Water is forced past a variable-depth sediment core sample in a closed channel, eroding sediments, and introducing suspended and bedload sediments into the flow stream. The core sample is continuously pushed into the flow stream, while keeping the surface level with the bottom of the channel. Eroded bedload sediments are transported downstream and then gravitationally separated from the flow stream into one or more quiescent traps. The captured bedload sediments (particles and aggregates) are weighed and compared to the total mass of sediment eroded, and also to the concentration of sediments suspended in the flow stream.

  5. Saturation of elliptic flow and shear viscosity

    E-Print Network [OSTI]

    A. K. Chaudhuri

    2007-10-08T23:59:59.000Z

    Effect of shear viscosity on elliptic flow is studied in causal dissipative hydrodynamics in 2+1 dimensions. Elliptic flow is reduced in viscous dynamics. Causal evolution of minimally viscous fluid ($\\eta/s$=0.08), can explain the PHENIX data on elliptic flow in 16-23% Au+Au collisions up to $p_T\\approx$3.6 GeV. In contrast, ideal hydrodynamics, can explain the same data only up to $p_T\\approx$1.5 GeV. $p_T$ spectra of identified particles are also better explained in minimally viscous fluid than in ideal dynamics. However, saturation of elliptic flow at large $p_T$ is not reproduced.

  6. Statement of Interest in a New Project, in response to PPARC call of April 26th FHIRN: A next-generation radio network for exploring the 3-dimensional solar wind

    E-Print Network [OSTI]

    -generation radio network for exploring the 3-dimensional solar wind Future Heliospheric Imaging Radio Network The solar wind is a supersonically-expanding extension of the solar atmosphere into interplanetary space and is the means by which solar disturbances and variability are carried out to the Earth and beyond. The outflow

  7. A Solid Core Heatpipe Reactor with Cylindrical Thermoelectric Converter Modules

    SciTech Connect (OSTI)

    Sayre, Edwin D. [218 Brooke Acres Drive, Los Gatos, CA 95032 (United States); Vaidyanathan, Sam [6663 Pomander Place, San Jose, CA 95120 (United States)

    2006-01-20T23:59:59.000Z

    A nuclear space power system that consists of a solid metal nuclear reactor core with heat pipes carrying energy to a cylindrical thermoelectric converter surrounding each of the heat pipes with a heat pipe radiator surrounding the thermoelectric converter is the most simple and reliable space power system. This means no single point of failure since each heat pipe and cylindrical converter is a separate power system and if one fails it will not affect the others. The heat pipe array in the solid core is designed so that if an isolated heat pipe or even two adjacent heat pipes fail, the remaining heat pipes will still transport the core heat without undue overheating of the uranium nitride fuel. The primary emphasis in this paper is on simplicity, reliability and fabricability of such a space nuclear power source. The core and heat pipes are made of Niobium 1% Zirconium alloy (Nb1Zr), with rhenium lined fuel tubes, bonded together by hot isostatic pressure (HIPing) and with sodium as the heat pipe working fluid, can be operated up to 1250K. The cylindrical thermoelectric converter is made by depositing the constituents of the converter around a Nb1%Zr tube and encasing it in a Nb 1% Zr alloy tube and HIPing the structure to get final bonding and to produce residual compressive stresses in all brittle materials in the converter. A radiator heat pipe filled with potassium that operates at 850K is bonded to the outside of the cylindrical converter for cooling. The solid core heat pipe and cylindrical converter are mated by welding during the final assembly. A solid core reactor with 150 heat pipes with a 0.650-inch (1.65 cm) ID and a 30-inch (76.2 cm) length with an output of 8 Watts per square inch as demonstrated by the SP100 PD2 cell tests will produce about 80 KW of electrical power. An advanced solid core reactor made with molybdenum 47% rhenium alloy, with lithium heat pipes and the PD2 theoretical output of 11 watts per square inch or advanced higher temperature converter to operate at 1350K could produce a greater output of approximately 100KW.

  8. Influence of inherent structure shear stress of supercooled liquids on their shear moduli

    E-Print Network [OSTI]

    Ingo Fuereder; Patrick Ilg

    2015-04-13T23:59:59.000Z

    Configurations of supercooled liquids residing in their local potential minimum (i.e. in their inherent structure, IS) were found to support a non-zero shear stress. This IS stress was attributed to the constraint to the energy minimization imposed by boundary conditions, which keep size and shape of the simulation cell fixed. In this paper we further investigate the influence of these boundary conditions on the IS stress. We investigate its importance for the computation of the low frequency shear modulus of a glass obtaining a consistent picture for the low- and high frequency shear moduli over the full temperature range. Hence, we find that the IS stress corresponds to a non-thermal contribution to the fluctuation term in the Born-Green expression. This leads to an unphysical divergence of the moduli in the low temperature limit if no proper correction for this term is applied. Furthermore, we clarify the IS stress dependence on the system size and put its origin on a more formal basis.

  9. Effect of normal stress during hydration and shear on the shear strength of GCL/textured geomembrane interfaces

    SciTech Connect (OSTI)

    Hewitt, R.D.; Soydemir, C. [Haley and Aldrich, Inc., Cambridge, MA (United States); Stulgis, R.P. [Haley and Aldrich, Inc., Manchester, NH (United States); Coombs, M.T. [Tufts Univ., Medford, MA (United States)

    1997-11-01T23:59:59.000Z

    A laboratory testing program was performed to evaluate the interface shear strength of a geosynthetic clay liner (GCL)/textured geomembrane interface utilizing two pre-shear inundation methods designed to simulate field conditions. Two commercially-available products were tested, a needlepunched and a stitch-bonded GCL. Oedometer swell tests provided swell data for the two products which were used to design the interface shear testing program. Interface shear tests were performed for (1) GCL samples inundated under a low normal stress for a short time and sheared under a higher normal stress, and (2) GCL samples inundated for a longer period under the design normal stress. The results for the two different GCL materials and the two preshear inundation conditions are compared.

  10. Shear bands in a bulk metallic glass after large plastic deformation

    SciTech Connect (OSTI)

    Qu, D.D.; Wang, Y.B.; Liao, X.Z.; Shen, J. (Harbin); (Sydney)

    2012-10-23T23:59:59.000Z

    A transmission electron microscopy investigation is conducted to trace shear bands in a Zr{sub 53}Cu{sub 18.7}Ni{sub 12}Al{sub 16.3} bulk metallic glass after experiencing 4% plastic deformation. Shear band initiation, secondary shear band interactions, mature shear band broadening and the interactions of shear bands with shear-induced nanocrystals are captured. Results suggest that the plasticity of the bulk metallic glass is enhanced by complex shear bands and their interactions which accommodate large plastic strain and prevent catastrophic shear band propagation.

  11. The Viability of Sustainable, Self-Propping Shear Zones in Ehanced...

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

    Self-Propping Shear Zones in Ehanced Geothermal Systems: Measurement of Reaction Rates at Elevated Temperatures The Viability of Sustainable, Self-Propping Shear Zones in...

  12. Methods for degrading or converting plant cell wall polysaccharides

    DOE Patents [OSTI]

    Berka, Randy (Davis, CA); Cherry, Joel (Davis, CA)

    2008-08-19T23:59:59.000Z

    The present invention relates to methods for converting plant cell wall polysaccharides into one or more products, comprising: treating the plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into the one or more products. The present invention also relates to methods for producing an organic substance, comprising: (a) saccharifying plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into saccharified material; (b) fermenting the saccharified material of step (a) with one or more fermenting microoganisms; and (c) recovering the organic substance from the fermentation.

  13. DeepWind WP3 D3.32 Technical Report Submersible Converter ........................................................................................................................................................................... 1

    E-Print Network [OSTI]

    Berning, Torsten

    ............................................................................................................................................... 3 2. Test Bench Converter for the 1 kW Floating VAWT Demonstrator

  14. Northwest Energy Innovations (TRL 5 6 System)- WETNZ MtiMode Wave Energy Converter Advancement Project

    Broader source: Energy.gov [DOE]

    Northwest Energy Innovations (TRL 5 6 System) - WETNZ MtiMode Wave Energy Converter Advancement Project

  15. High speed bypass Fig. 1. Sub-module of MMC converter

    E-Print Network [OSTI]

    Chaudhary, Sanjay

    Modular Converter for VSC-HVDC Transmission Applications: Control and Operational Aspects Udana N, the multilevel modular converter (MMC), recently introduced for HVDC transmission are discussed. The paper. Keywords-Voltage Source Convert (VSC), Multilevel Modular Converter (MMC), HVDC Transmission, Weak ac

  16. An improved viscosity equation to characterize shear-thinning fluids

    SciTech Connect (OSTI)

    Allen, E.

    1995-11-01T23:59:59.000Z

    An improved viscosity equation is proposed for shear-thinning polymer solutions, using a kinetic approach to model the rate of formation and loss of interactive bonding during shear flow. The bonds are caused by temporary polymer entanglements in polymer solutions, and by coordination bonding in metal ion cross-linked gels. The equation characterizes the viscosity of shear-thinning fluids over a wide range of shear rates, from the zero shear region through to infinite shear viscosity. The equation has been used to characterize fluid data from a wide range of fluids. Recent work indicates that a range of polymer solutions, polymer-based drilling fluids and frac-gels do not have a measurable yield stress, and that the equations which use extrapolated values of yield stress can be significantly in error. The new equation is compared with the Carreau and Cross equations, using the correlation procedure of Churchill and Usagi. It gives a significantly better fit to the data (by up to 50%) over a wide range of shear rates. The improved equation can be used for evaluating the fluid viscosity during the flow of polymeric fluids, in a range of oilfield applications including drilling, completion, stimulation and improved recovery (IOR) processes.

  17. Rayleigh-Taylor instabilities with sheared magnetic fields

    SciTech Connect (OSTI)

    Ruderman, M. S. [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Terradas, J.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

    2014-04-20T23:59:59.000Z

    Magnetic Rayleigh-Taylor (MRT) instabilities may play a relevant role in many astrophysical problems. In this work the effect of magnetic shear on the growth rate of the MRT instability is investigated. The eigenmodes of an interface and a slab model under the presence of gravity are analytically calculated assuming that the orientation of the magnetic field changes in the equilibrium, i.e., there is magnetic shear. We solve the linearized magnetohydrodynamic equations in the incompressible regime. We find that the growth rate is bounded under the presence of magnetic shear. We have derived simple analytical expressions for the maximum growth rate, corresponding to the most unstable mode of the system. These expressions provide the explicit dependence of the growth rate on the various equilibrium parameters. For small angles the growth time is linearly proportional to the shear angle, and in this regime the single interface problem and the slab problem tend to the same result. On the contrary, in the limit of large angles and for the interface problem the growth time is essentially independent of the shear angle. In this regime we have also been able to calculate an approximate expression for the growth time for the slab configuration. Magnetic shear can have a strong effect on the growth rates of the instability. As an application of the results found in this paper we have indirectly determined the shear angle in solar prominence threads using their lifetimes and the estimation of the Alfvén speed of the structure.

  18. A Shear Thickening transition in concentrated suspensions under Impact

    E-Print Network [OSTI]

    Shomeek Mukhopadhyay; Benjamin Allen; Eric Brown

    2014-07-07T23:59:59.000Z

    Discontinous Shear Thickening (DST) fluids show a remarkable effect where the suspension behaves like a liquid at low shear rates, but when sheared very hard, resistance to flow increases discontinously with shear rate. This effect has been observed in a large variety of concentrated suspensions of hard, frictional and non attractive particles. DST fluids also show strong impact response such as the ability of a person to run on the surface of a pool filled with a suspension of cornstarch and water. Current models of shear thickening based on lubrication hydrodynamics, dilatancy, and inertial displacement fail to explain the ability of a person to run on the surface and impact response in general. In our experiments we discover a transition at a critical impact velocity in DST fluids above which fronts of solid like regions are generated in the fluid and the collision of these fronts with a solid boundary leads to a shear thickening transition which has not been previously predicted or reported. The large stresses generated above the shear thickening transition are enough to hold up the weight of a person and have potential applications for protective materials.

  19. Shear band dynamics from a mesoscopic modeling of plasticity

    E-Print Network [OSTI]

    E. A. Jagla

    2010-06-07T23:59:59.000Z

    The ubiquitous appearance of regions of localized deformation (shear bands) in different kinds of disordered materials under shear is studied in the context of a mesoscopic model of plasticity. The model may or may not include relaxational (aging) effects. In the absence of relaxational effects the model displays a monotonously increasing dependence of stress on strain-rate, and stationary shear bands do not occur. However, in start up experiments transient (although long lived) shear bands occur, that widen without bound in time. I investigate this transient effect in detail, reproducing and explaining a t^1/2 law for the thickness increase of the shear band that has been obtained in atomistic numerical simulations. Relaxation produces a negative sloped region in the stress vs. strain-rate curve that stabilizes the formation of shear bands of a well defined width, which is a function of strain-rate. Simulations at very low strain-rates reveal a non-trivial stick-slip dynamics of very thin shear bands that has relevance in the study of seismic phenomena. In addition, other non-stationary processes, such as stop-and-go, or strain-rate inversion situations display a phenomenology that matches very well the results of recent experimental studies.

  20. Automated Patient Identification and Localization Error Detection Using 2-Dimensional to 3-Dimensional Registration of Kilovoltage X-Ray Setup Images

    SciTech Connect (OSTI)

    Lamb, James M., E-mail: jlamb@mednet.ucla.edu; Agazaryan, Nzhde; Low, Daniel A.

    2013-10-01T23:59:59.000Z

    Purpose: To determine whether kilovoltage x-ray projection radiation therapy setup images could be used to perform patient identification and detect gross errors in patient setup using a computer algorithm. Methods and Materials: Three patient cohorts treated using a commercially available image guided radiation therapy (IGRT) system that uses 2-dimensional to 3-dimensional (2D-3D) image registration were retrospectively analyzed: a group of 100 cranial radiation therapy patients, a group of 100 prostate cancer patients, and a group of 83 patients treated for spinal lesions. The setup images were acquired using fixed in-room kilovoltage imaging systems. In the prostate and cranial patient groups, localizations using image registration were performed between computed tomography (CT) simulation images from radiation therapy planning and setup x-ray images corresponding both to the same patient and to different patients. For the spinal patients, localizations were performed to the correct vertebral body, and to an adjacent vertebral body, using planning CTs and setup x-ray images from the same patient. An image similarity measure used by the IGRT system image registration algorithm was extracted from the IGRT system log files and evaluated as a discriminant for error detection. Results: A threshold value of the similarity measure could be chosen to separate correct and incorrect patient matches and correct and incorrect vertebral body localizations with excellent accuracy for these patient cohorts. A 10-fold cross-validation using linear discriminant analysis yielded misclassification probabilities of 0.000, 0.0045, and 0.014 for the cranial, prostate, and spinal cases, respectively. Conclusions: An automated measure of the image similarity between x-ray setup images and corresponding planning CT images could be used to perform automated patient identification and detection of localization errors in radiation therapy treatments.

  1. The important effect of electron reflection on thermionic converter performance

    SciTech Connect (OSTI)

    Rasor, N.S.

    1998-07-01T23:59:59.000Z

    Although only a few percent of high energy electrons are reflected from bare metal surfaces, 20--60% of low energy incident electrons are reflected from thermionic converter electrodes with adsorbed cesium and oxygen. The TECMDL computer model indicates that electron reflection in cesium vapor thermionic converters increases the arc potential drop, offsetting the gain in performance obtainable by lowering the collector work function via the coadsorbed Cs/O layer. The possible suppression of electron reflection by using electrodes with sub-micron surface structure is hypothesized and supported by experimental data obtained by employing a new method for testing in cesium-oxygen vapor.

  2. Process for converting cellulosic materials into fuels and chemicals

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN); Faison, Brendlyn D. (Knoxville, TN); Davison, Brian H. (Knoxville, TN); Woodward, Jonathan (Oak Ridge, TN)

    1994-01-01T23:59:59.000Z

    A process for converting cellulosic materials, such as waste paper, into fuels and chemicals utilizing enzymatic hydrolysis of the major constituent of paper, cellulose. A waste paper slurry is contacted by cellulase in an agitated hydrolyzer. The cellulase is produced from a continuous, columnar, fluidized-bed bioreactor utilizing immobilized microorganisms. An attritor and a cellobiase reactor are coupled to the agitated hydrolyzer to improve reaction efficiency. The cellulase is recycled by an adsorption process. The resulting crude sugars are converted to dilute product in a fluidized-bed bioreactor utilizing microorganisms. The dilute product is concentrated and purified by utilizing distillation and/or a biparticle fluidized-bed bioreactor system.

  3. Method for converting sucrose to .beta.-D-glucose

    DOE Patents [OSTI]

    Simmons, Blake A. (San Francisco, CA); Volponi, Joanne V. (Livermore, CA); Ingersoll, David (Albuquerque, NM); Walker, Andrew (Woodinville, WA)

    2009-07-07T23:59:59.000Z

    Disclosed is an apparatus and method for continuously converting sucrose to .beta.-D-glucose. The method comprises a three-stage enzymatic reactor in which an aqueous solution of sucrose is first converted into a solution of fructose and .alpha.-D-glucose by passing it through a porous, packed column containing an inert media on which invertase is immobilized. This solution is then sent through a second packed column containing glucose isomerase and finally a third packed column containing mutarotase. Solution temperature and pH are adjusted to maximize glucose output.

  4. Direct recovery of fluctuation spectra from tomographic shear spectra

    SciTech Connect (OSTI)

    Mezzetti, Marino; Bonometto, Silvio A.; Murante, Giuseppe [Department of Physics, Astronomy Unit, Trieste University, Via Tiepolo 11, I 34143 Trieste (Italy); Casarini, Luciano, E-mail: mezzetti@oats.inaf.it, E-mail: bonometto@oats.inaf.it, E-mail: casarini@mib.infn.it, E-mail: murante@oats.inaf.it [Departamento de Fisica, UFES, Avenida Fernando Ferrari 514, Vitória, Espírito Santo (Brazil)

    2012-06-01T23:59:59.000Z

    Forthcoming experiments will enable us to determine high precision tomographic shear spectra. Matter density fluctuation spectra, at various z, should then be recovered from them, in order to constrain the model and determine the DE state equation. Available analytical expressions, however, do the opposite, enabling us to derive shear spectra from fluctuation spectra. Here we find the inverse expression, yielding density fluctuation spectra from observational tomographic shear spectra. The procedure involves SVD techniques for matrix inversion. We show in detail how the approach works and provide a few examples.

  5. Piezoelectric shear wave resonator and method of making same

    DOE Patents [OSTI]

    Wang, J.S.; Lakin, K.M.; Landin, A.R.

    1985-05-20T23:59:59.000Z

    An acoustic shear wave resonator comprising a piezoelectric film having its C-axis substantially inclined from the film normal such that the shear wave coupling coefficient significantly exceeds the longitudinal wave coupling coefficient, whereby the film is capable of shear wave resonance, and means for exciting said film to resonate. The film is prepared by deposition in a dc planar magnetron sputtering system to which a supplemental electric field is applied. The resonator structure may also include a semiconductor material having a positive temperature coefficient of resonance such that the resonator has a temperature coefficient of resonance approaching 0 ppM//sup 0/C.

  6. Coherent structures in compressible free-shear-layer flows

    SciTech Connect (OSTI)

    Aeschliman, D.P.; Baty, R.S. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center; Kennedy, C.A.; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion and Physical Sciences Center

    1997-08-01T23:59:59.000Z

    Large scale coherent structures are intrinsic fluid mechanical characteristics of all free-shear flows, from incompressible to compressible, and laminar to fully turbulent. These quasi-periodic fluid structures, eddies of size comparable to the thickness of the shear layer, dominate the mixing process at the free-shear interface. As a result, large scale coherent structures greatly influence the operation and efficiency of many important commercial and defense technologies. Large scale coherent structures have been studied here in a research program that combines a synergistic blend of experiment, direct numerical simulation, and analysis. This report summarizes the work completed for this Sandia Laboratory-Directed Research and Development (LDRD) project.

  7. The effect of dynamic simple shear on marine sediment 

    E-Print Network [OSTI]

    Carpenter, Samuel Harley

    1972-01-01T23:59:59.000Z

    radian where the difference is only ten percent. rt Then 6 =? h and: d9 r dt h This value is a constant for any one test. It gives a reasonable value to use for any one deformation rate, and will be called the shear deformation rate in this study... . The average strain to failure for the shear-viscometer tests is 0. 51 radians. This corresponds to 0. 14 inches defor- mation or 6. 6 percent strain. The values for shear strain varied between 4. 2 and 8. 9 percent strain to failure. This value...

  8. Comparison of architectures for two-step flash analog-to-digital converters 

    E-Print Network [OSTI]

    Reese, Robert Bryan

    1982-01-01T23:59:59.000Z

    A/D converters have been designed and fabricated in the last three to five ?om a survey of the literature it was discovered that the majority of these converters were of the successive approximation (SAP) type (Table I, page 4). This is because... the SAP converter offers a fast conversion time, a low complexity level and a small area requirement. Only one comparator, the design critical subcircuit of most converters, is needed in a SAP converter. Area requirements increase only moderately...

  9. Symmetry related dynamics in parallel shear flows

    E-Print Network [OSTI]

    Tobias Kreilos; Stefan Zammert; Bruno Eckhardt

    2014-04-23T23:59:59.000Z

    Parallel shear flows come with continuous symmetries of translation in the downstream and spanwise direction. As a consequence, flow states that differ in their spanwise or downstream location but are otherwise identical are dynamically equivalent. In the case of travelling waves, this trivial degree of freedom can be removed by going to a frame of reference that moves with the state, thereby turning the travelling wave in the laboratory frame to a fixed point in the comoving frame of reference. We here discuss a general method by which the translational displacements can be removed also for more complicated and dynamically active states and demonstrate its application for several examples. For flows states in the asymptotic suction boundary layer we show that in the case of the long-period oscillatory edge state we can find local phase speeds which remove the fast oscillations and reveal the slow vortex dynamics underlying the burst phenomenon. For spanwise translating states we show that the method removes the drift but not the dynamical events that cause the big spanwise displacement. For a turbulent case we apply the method to the spanwise shifts and find slow components that are correlated over very long times. Calculations for plane Poiseuille flow show that the long correlations in the transverse motions are not special to the asymptotic suction boundary layer.

  10. Introduction to workshop on spectral control and converters

    SciTech Connect (OSTI)

    Wanlass, M.W.; Schwartz, R.J.

    1995-01-05T23:59:59.000Z

    This workshop focused on the portion of the TPV system that involves the photovoltaic energy converter and the spectral control element that affects subband-gap photon energy recovery. The discussion was divided into three major topic areas: status of the technology, status of the infrastructure, and champions of the technology. (AIP) {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. Pre-converted nitric oxide gas in catalytic reduction system

    DOE Patents [OSTI]

    Hsiao, M.C.; Merritt, B.T.; Penetrante, B.M.; Vogtlin, G.E.

    1999-04-06T23:59:59.000Z

    A two-stage catalyst comprises an oxidative first stage and a reductive second stage. The first stage is intended to convert NO to NO{sub 2} in the presence of O{sub 2}. The second stage serves to convert NO{sub 2} to environmentally benign gases that include N{sub 2}, CO{sub 2}, and H{sub 2}O. By preconverting NO to NO{sub 2} in the first stage, the efficiency of the second stage for NO{sub x} reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber. An oxidizing first catalyst converts NO to NO{sub 2} in the presence of O{sub 2} and includes platinum/alumina, e.g., Pt/Al{sub 2}O{sub 3} catalyst. A flow of hydrocarbons (C{sub x}H{sub y}) is input from a pipe into a second chamber. For example, propene can be used as a source of hydrocarbons. The NO{sub 2} from the first catalyst mixes with the hydrocarbons in the second chamber. The mixture proceeds to a second reduction catalyst that converts NO{sub 2} to N{sub 2}, CO{sub 2}, and H{sub 2}O, and includes a {gamma}-Al{sub 2}O{sub 3}. The hydrocarbons and NO{sub x} are simultaneously reduced while passing through the second catalyst. 9 figs.

  12. A/D Converter Jee-Hwan Ryu

    E-Print Network [OSTI]

    Ryu, Jee-Hwan

    A/D , MUX and REFS update #12;Korea University of Technology and Education ADSC=1 of Technology and Education Korea University of Technology and Education A/D converter #12;Korea University of Technology and Education () AD > -> X = 1 Korea University of Technology and Education AD #12;Korea

  13. Performance Assessment of the Wave Dragon Wave Energy Converter

    E-Print Network [OSTI]

    Hansen, René Rydhof

    Performance Assessment of the Wave Dragon Wave Energy Converter Based on the EquiMar Methodology S of the wave energy sector, device developers are called to provide reliable estimates on power performanceMar, Nissum Bredning, Hanstholm, North Sea, Ekofisk, Wave-to-wire, Wave energy. I. INTRODUCTION The wave

  14. Pre-converted nitric oxide gas in catalytic reduction system

    DOE Patents [OSTI]

    Hsiao, Mark C. (Livermore, CA); Merritt, Bernard T. (Livermore, CA); Penetrante, Bernardino M. (San Ramon, CA); Vogtlin, George E. (Fremont, CA)

    1999-01-01T23:59:59.000Z

    A two-stage catalyst comprises an oxidative first stage and a reductive second stage. The first stage is intended to convert NO to NO.sub.2 in the presence of O.sub.2. The second stage serves to convert NO.sub.2 to environmentally benign gases that include N2, CO2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber. An oxidizing first catalyst converts NO to NO.sub.2 in the presence of O.sub.2 and includes platinum/alumina, e.g., Pt/Al.sub.2 O.sub.3 catalyst. A flow of hydrocarbons (C.sub.x H.sub.y) is input from a pipe into a second chamber. For example, propene can be used as a source of hydrocarbons. The NO.sub.2 from the first catalyst mixes with the hydrocarbons in the second chamber. The mixture proceeds to a second reduction catalyst that converts NO.sub.2 to N2, CO2, and H.sub.2 O, and includes a gamma-alumina .gamma.-Al.sub.2 O.sub.3. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the second catalyst.

  15. Simulation Model for UltrasonicMotors powered by Resonant Converters

    E-Print Network [OSTI]

    Paderborn, Universität

    of the stator, producing a traveling wave. This process can be assumed as a linear phenomenon. In a second for the drive. Based on recent mechanical approaches in modelingthe stator under considerationof unsymmetriesand-modeapproximationof the stator and piezoceramic. Incorporation of a converter model into the mechanicalsubsystem a proper

  16. Coupled Dual Interleaved Flyback Converter for High Input Voltage Application

    E-Print Network [OSTI]

    Lehman, Brad

    components, including transformers and inductors, significantly influences the overall profiles magnetic core to store the energy in the power transformer. A Flyback converter is a popular choice for low. All the center and outer legs are gapped, and the transformers are integrated into one magnetic core

  17. Soft switched high frequency ac-link converter 

    E-Print Network [OSTI]

    Balakrishnan, Anand Kumar

    2009-05-15T23:59:59.000Z

    topology for medium and high power ac-ac, ac-dc and dc-ac applications. An ac-link formed by an inductor-capacitor pair replaces the conventional dc-link. Each leg of the converter is formed by two bidirectional switches. Power transfer from input to output...

  18. Energy Savings Assessment for Digital-to-Analog Converter Boxes

    SciTech Connect (OSTI)

    Cheung, Hoi Ying Iris; Meier, Alan; Brown, Richard

    2011-01-18T23:59:59.000Z

    The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.

  19. "Black Box" EMC model for Power Electronics Converter Mikael Foissac

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    "Black Box" EMC model for Power Electronics Converter Mikael Foissac Grenoble Electrical be forecasted accurately, in order to avoid disturbance of the complete system. To quantify the EMC behaviour will then illustrate the method on a complete chopper cell. II. BLACK BOX EMC MODEL Any EMC analysis must account

  20. A summary of North American HVDC converter station reliability specifications

    SciTech Connect (OSTI)

    Vancers, I. (ABB Power Systems Inc., Los Angeles, CA (United States)); Hormozi, F.J. (Los Angeles Dept. of Water and Power, CA (United States))

    1993-07-01T23:59:59.000Z

    This paper summarizes Reliability, Availability, and Maintainability (RAM) specifications that were issued for thyristor based HVDC converter stations in service in North America. A total of twenty project specifications are summarized. A detailed summary by project is shown with specific quantitative requirements categorized. Definitions of terms, representative design principles, and formulas used in calculating RAM parameters contained in existing reliability specifications are presented.

  1. INVERSION OF CONVERTED-WAVE SEISMIC DATA FOR RESERVOIR CHARACTERIZATION

    E-Print Network [OSTI]

    INVERSION OF CONVERTED-WAVE SEISMIC DATA FOR RESERVOIR CHARACTERIZATION AT RULISON FIELD, COLORADO Basin of northwest Colorado. The reservoir consists of lenticular fluvial sands, shales, and coals of magnitude lower than the seismic resolution which is 105 ft. The sandstone reservoirs are the primary target

  2. Vane shear determination of the visco-elastic shear modulus of submarine sediments 

    E-Print Network [OSTI]

    Stevenson, Herbert Scott

    1973-01-01T23:59:59.000Z

    viscoelastic theory and torque versus rotation data from vane shear tests. The modu- lus, G(t), is described by the power law: G(t) = G, t where t is time, and G, and n are constants. G, and n are deter- mined from vane tests on deep sediment core samples.... G, is rota- tion angle dependent. The validity of the procedure is supported by predict1ons of in situ vane test torque versus rotation curves wh1ch agree favorably with data obtained using an in s1tu vane device. G, correlates with maximum vane...

  3. Interfacial colloidal monolayers under steady shear: structure and flow profiles

    E-Print Network [OSTI]

    Ivo Buttinoni; Zachary A. Zell; Todd M. Squires; Lucio Isa

    2015-04-01T23:59:59.000Z

    We study the coupling between the structural dynamics and rheological response of charged colloidal monolayers at water/oil interfaces, driven into steady shear by a microdisk rotating at a controlled angular velocity. The flow causes particles to layer into rotating concentric rings linked to the local, position-dependent shear rate, which triggers two distinct dynamical regimes: particles move continuously "Flowing") close to the microdisk, or exhibit intermittent "Hopping" between local energy minima farther away. The shear-rate dependent surface viscosity of a monolayer can be extracted from an interfacial stress balance, giving "macroscopic" flow curves whose behavior corresponds to the distinct microscopic regimes of particle motion. Hopping Regions correspond to a surface yield stress $\\eta \\sim \\tau_S^Y \\dot{\\gamma}^{-1}$, whereas Flowing Regions exhibit surface viscosities with power-law shear-thinning characteristics.

  4. Wind Shear Characteristics at Central Plains Tall Towers: Preprint

    SciTech Connect (OSTI)

    Schwartz, M.; Elliott, D.

    2006-06-01T23:59:59.000Z

    Conference paper for WindPower 2006 held June 4-7, 2006, in Pittsburgh, PA, describing the wind shear characteristics at tall tower sites in the Central Plains of the United States.

  5. Shear measurements across the northern margin of Whillans Ice Stream

    E-Print Network [OSTI]

    Van Der Veen, C.J.; Jezek, K.; Stearns, Leigh

    2007-01-01T23:59:59.000Z

    Field measurements of surface deformation across the northern shear margin of Whillans Ice Stream, West Antarctica, were analyzed to better understand the processes controlling the position and migration of this margin. Four lines of poles extending...

  6. Reflection and Exclusion of Shear Zones in Inhomogeneous Granular Materials

    E-Print Network [OSTI]

    Tamas Borzsonyi; Tamas Unger; Balazs Szabo; Sandra Wegner; Frank Angenstein; Ralf Stannarius

    2011-08-17T23:59:59.000Z

    Shear localization in granular materials is studied experimentally and numerically. The system consists of two material layers with different effective frictions. The presence of the material interface leads to a special type of "total internal reflection" of the shear zone. In a wide range of configurations the reflection is characterized by a fixed angle which is analogous to the critical angle of refraction in optics. The zone leaves and reenters the high friction region at this critical angle and in between it stays near the interface in the low friction region. The formalism describing the geometry of the shear zones and that of refracted and reflected light beams is very similar. For the internal visualization of shear localization two independent experimental techniques were used (i) excavation and (ii) Magnetic Resonance Imaging.

  7. Recovery of fluctuation spectrum evolution from tomographic shear spectra

    SciTech Connect (OSTI)

    Bonometto, Silvio A.; Mezzetti, Marino, E-mail: bonometto@oats.inaf.it, E-mail: mezzetti@oats.inaf.it [Department of Physics, Astronomy Unit, Trieste University, Via Tiepolo 11, I 34143 Trieste (Italy)

    2013-05-01T23:59:59.000Z

    Forthcoming large angle surveys are planned to obtain high precision tomographic shear data. In principle, they will allow us to recover the spectra of matter density fluctuation, at various redshift, through the inversion of the expressions yielding shear spectra from fluctuation spectra. This was discussed in previous work, where SVD techniques for matrix inversion were also shown to be the optimal tool to this aim. Here we show the significant improvements obtainable by using a 7 bin tomography, as allowed by future Euclid data, and discuss error propagation from shear to fluctuation spectra. We find that the technique is a promising tool, namely for the analysis of baryon physics through high–l shear spectra and to test the consistency between expansion rate and fluctuation growth.

  8. Estimating A Shear Modulus Of A Transversely Isotropic Formation

    E-Print Network [OSTI]

    Ellefsen, K. J.

    1990-01-01T23:59:59.000Z

    A method to estimate c[subscript 66], which is a shear modulus of a transversely isotropic formation (with its symmetry axis parallel to the borehole), is developed and tested. The inversion for c[subscript 66] is based ...

  9. Polymer dynamics in random flow with mean shear K. Turitsyn

    E-Print Network [OSTI]

    Fominov, Yakov

    Polymer dynamics in random flow with mean shear K. Turitsyn Landau Institute for theoretical;Outline · Motivation: Elastic turbulence · Experimental setup · Flow and polymer models · Results: 1. Angular statistics 2. Polymer elongation distribution · Conclusion #12;Elastic Turbulence Elastic

  10. Active, polymer-based composite material implementing simple shear

    E-Print Network [OSTI]

    Lee, Sang Jin

    2009-05-15T23:59:59.000Z

    A novel active material for controllable, high work density applications was designed, fabricated, analyzed, and tested. This active material uses a lens-shaped element to implement simple shear motion with gas pressure actuation. The lens element...

  11. Glycocalyx acting as a mechanotransducer of fluid shear stress

    E-Print Network [OSTI]

    Yao, Yu, Ph. D. Massachusetts Institute of Technology

    2005-01-01T23:59:59.000Z

    It is widely recognized that fluid shearing forces acting on endothelial cells (ECs) have a profound effect on EC morphology, structure and function. Recent investigations in vivo have indicated the presence of a thick ...

  12. Numerical method for shear bands in ductile metal with inclusions

    SciTech Connect (OSTI)

    Plohr, Jee Yeon N [Los Alamos National Laboratory; Plohr, Bradley J [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    A numerical method for mesoscale simulation of high strain-rate loading of ductile metal containing inclusions is described. Because of small-scale inhomogeneities, such a composite material is prone to localized shear deformation (adiabatic shear bands). The modeling framework is the Generalized Method of Cells of Paley and Aboudi [Mech. Materials, vol. 14, pp. /27-139, 1992], which ensures that the micromechanical response of the material is reflected in the behavior of the composite at the mesoscale. To calculate the effective plastic strain rate when shear bands are present, the analytic and numerical analysis of shear bands by Glimm, Plohr, and Sharp [Mech. Materials, vol. 24, pp. 31-41, 1996] is adapted and extended.

  13. Landfill liner interface strengths from torsional-ring-shear tests

    SciTech Connect (OSTI)

    Stark, T.D. (Univ. of Illinois, Urbana, IL (United States)); Poeppel, A.R. (Langan Engineering Associates, Inc., New York, NY (United States))

    1994-03-01T23:59:59.000Z

    A torsional-ring-shear apparatus and test procedure are described for measuring soil/geosynthetic and geosynthetic/geosynthetic interface strengths. Typical interface strengths are presented for a double-composite liner system and the relevancy of ring-shear strengths is illustrated using the slope failure at the Kettleman Hills Waste Repository, Kettleman City, Calif. The results of undrained ring-shear tests show that for a clay/geomembrane interface: (1) interface strength depends on plasticity and compaction water content of the clay, and the applied normal stress; (2) interface strengths measured with the torsional-ring-shear apparatus are in excellent agreement with back-calculated field strengths; and (3) peak and residual interface failure envelopes are nonlinear, and the nonlinearity should be modeled in stability analyses instead of as a combination of cohesion and friction angle. Design recommendations for interface strengths and stability analyses are also presented.

  14. Transport bifurcation induced by sheared toroidal flow in tokamak plasmas

    SciTech Connect (OSTI)

    Highcock, E. G.; Barnes, M. [Rudolph Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Parra, F. I.; Schekochihin, A. A. [Rudolph Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Roach, C. M.; Cowley, S. C. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2011-10-15T23:59:59.000Z

    First-principles numerical simulations are used to describe a transport bifurcation in a differentially rotating tokamak plasma. Such a bifurcation is more probable in a region of zero magnetic shear than one of finite magnetic shear, because in the former case the component of the sheared toroidal flow that is perpendicular to the magnetic field has the strongest suppressing effect on the turbulence. In the zero-magnetic-shear regime, there are no growing linear eigenmodes at any finite value of flow shear. However, subcritical turbulence can be sustained, owing to the existence of modes, driven by the ion temperature gradient and the parallel velocity gradient, which grow transiently. Nonetheless, in a parameter space containing a wide range of temperature gradients and velocity shears, there is a sizeable window where all turbulence is suppressed. Combined with the relatively low transport of momentum by collisional (neoclassical) mechanisms, this produces the conditions for a bifurcation from low to high temperature and velocity gradients. A parametric model is constructed which accurately describes the combined effect of the temperature gradient and the flow gradient over a wide range of their values. Using this parametric model, it is shown that in the reduced-transport state, heat is transported almost neoclassically, while momentum transport is dominated by subcritical parallel-velocity-gradient-driven turbulence. It is further shown that for any given input of torque, there is an optimum input of heat which maximises the temperature gradient. The parametric model describes both the behaviour of the subcritical turbulence (which cannot be modelled by the quasi-linear methods used in current transport codes) and the complicated effect of the flow shear on the transport stiffness. It may prove useful for transport modelling of tokamaks with sheared flows.

  15. Simulated performance of an airborne lidar wind shear detection system

    E-Print Network [OSTI]

    Griffith, Kenneth Scott

    1987-01-01T23:59:59.000Z

    SIMULATED PERFORMANCE OF AN AIRBORNE LIDAR WIND SHEAR DETECTION SYSTEM A Thesis by KENNETH SCOTT GRIFFITH Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1987 Major Subject: Physics SIMULATED PERFORMANCE OF AN AIRBORNE LIDAR WIND SHEAR DETECTION SYSTEM A Thesis by KENNETH SCOTT GRIFFITH Approved as to style and content by: e . atta ar (Chair an of Committee) T omas . air, III (Member) ic...

  16. Parallel-Flow-Shear Driven Low-Frequency Plasma Instability

    SciTech Connect (OSTI)

    Ishiguro, Seiji [Theory and Computer Simulation Center, National Institute for Fusion Science, Toki-shi, Gifu 509-5292 (Japan); Matsumoto, Noriaki; Kaneko, Toshiro; Hatakeyama, Rikizo [Department of Electronic Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2004-12-01T23:59:59.000Z

    Full three dimensional Particle-in-Cell (PIC) simulations are performed in order to investigate effects of field-aligned (parallel) ion flow shears on low-frequency plasma instabilities. It is shown that the parallel ion flow velocity shear can induce the ion-acoustic instability, even when the ion flow velocity is so small that the instability can not take place. Simulation results are consistent with the analysis based on the local theory.

  17. Comment on "Accelerating cosmological expansion from shear and bulk viscosity"

    E-Print Network [OSTI]

    Giovannini, Massimo

    2015-01-01T23:59:59.000Z

    In a recent Letter [Phys. Rev. Lett. 114 091301 (2105)] the cause of the acceleration of the present Universe has been identified with the shear viscosity of an imperfect relativistic fluid even in the absence of any bulk viscous contribution. The gist of this comment is that the shear viscosity, if anything, can only lead to an accelerated expansion over sufficiently small scales well inside the Hubble radius.

  18. Multiplicity of low-shear toroidal Alfven eigenmodes

    SciTech Connect (OSTI)

    Candy, J. [JET Joint Undertaking, Abingdon (United Kingdom); Breizman, B.N. [Univ. of Texas, Austin (United States). Inst. for Fusion Studies]|[Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation); Van Dam, J.W. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies; Ozeki, T. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-01-01T23:59:59.000Z

    An enlarged spectrum of ideal toroidal Alfven eigenmodes is demonstrated to exist within a toroidicity-induced Alfven gap when the inverse aspect ratio is comparable to or larger than the value of the magnetic shear. This limit is appropriate for the low-shear region in most tokamaks, especially those with low aspect ratio. The new modes may be destabilized by fusion-product alpha particles more easily than the standard toroidal Alfven eigenmodes.

  19. Critical behaviors of sheared frictionless granular materials near jamming transition

    E-Print Network [OSTI]

    Michio Otsuki; Hisao Hayakawa

    2009-06-25T23:59:59.000Z

    Critical behaviors of sheared dense and frictionless granular materials in the vicinity of the jamming transition are numerically investigated. From the extensive molecular dynamics simulation, we verify the validity of the scaling theory near the jamming transition proposed by Otsuki and Hayakawa (Prog. Theor. Phys., 121, 647 (2009)). We also clarify the critical behaviors of the shear viscosity and the pair correlation function based on both a phenomenology and the simulation.

  20. GAISUS-1 thermionic converter for the integrated solar upper stage

    SciTech Connect (OSTI)

    Begg, L.L.; Heffernan, T.F.; Horner, M.H. [General Atomics, San Diego, CA (United States)

    1997-12-31T23:59:59.000Z

    The Integrated Solar Upper Stage (ISUS) system is a compact orbital transfer vehicle which generates thrust to boost payloads from LEO to higher orbits. It does this by collecting and concentrating solar flux into a sensible thermal storage, graphite receiver which is used to heat hydrogen propellant to temperatures of up to 2500 K. The ISUS receiver also radiates heat into an array of thermionic converters which produce electrical power. The GAISUS-1 thermionic converter is a first generation planar converter designed to produce electrical power when coupled with the ISUS receiver. GAISUS-1 will deliver over 31 W{sub e} at 1900 K. A wrought Re hotshoe accepts radiant heat from the receiver. The back side of the hotshoe forms the emitting surface of the converter. Special attention was paid to optimize the electrical and thermal losses experienced through the sleeve. Triple and single sleeve geometries were thermally modeled and evaluated, resulting in the selection of a single sleeve design. A high temperature metal/ceramic seal isolates the emitter sleeve from the collector. A Nb collector is used and is an integral part of a Nb/Na heat pipe. The heat pipe transports reject heat from the collector surface to a thermal radiator (condenser) portion of the heat pipe. The converter utilizes an integral graphite Cs reservoir. This type of reservoir automatically produces a rise in Cs pressure in response to a rise in emitter/collector temperatures. This Cs pressure feedback mechanism insures adequate Cs coverage of the emitter over a broad range of operating conditions (temperatures).

  1. Technical Paper by T.D. Stark and H.T. Eid SHEAR BEHAVIOR OF REINFORCED

    E-Print Network [OSTI]

    Technical Paper by T.D. Stark and H.T. Eid SHEAR BEHAVIOR OF REINFORCED GEOSYNTHETIC CLAY LINERS strength between a geomembrane and a reinforced geosynthetic clay liner (GeL), and the internal shear: Geosynthetic clay liner, Strength, Stability, Slope, Shearbox test, Shear rate, Ring shear test. AUTHORS: T

  2. Potential for Improved Intelligence Quotient Using Volumetric Modulated Arc Therapy Compared With Conventional 3-Dimensional Conformal Radiation for Whole-Ventricular Radiation in Children

    SciTech Connect (OSTI)

    Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, California (United States); Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States); Stinauer, Michelle; Rogers, Brion [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States)] [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States); Madden, Jennifer R. [Department of Neuro-Oncology, The Children's Hospital, Aurora, Colorado (United States)] [Department of Neuro-Oncology, The Children's Hospital, Aurora, Colorado (United States); Wilkening, Greta N. [Department of Pediatrics, The Children's Hospital, Aurora, Colorado (United States)] [Department of Pediatrics, The Children's Hospital, Aurora, Colorado (United States); Liu, Arthur K. [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States)] [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States)

    2012-12-01T23:59:59.000Z

    Purpose: To compare volumetric modulated arc therapy (VMAT) with 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of localized intracranial germinoma. We modeled the effect of the dosimetric differences on intelligence quotient (IQ). Method and Materials: Ten children with intracranial germinomas were used for planning. The prescription doses were 23.4 Gy to the ventricles followed by 21.6 Gy to the tumor located in the pineal region. For each child, a 3D-CRT and full arc VMAT was generated. Coverage of the target was assessed by computing a conformity index and heterogeneity index. We also generated VMAT plans with explicit temporal lobe sparing and with smaller ventricular margin expansions. Mean dose to the temporal lobe was used to estimate IQ 5 years after completion of radiation, using a patient age of 10 years. Results: Compared with the 3D-CRT plan, VMAT improved conformality (conformity index 1.10 vs 1.85), with slightly higher heterogeneity (heterogeneity index 1.09 vs 1.06). The averaged mean doses for left and right temporal lobes were 31.3 and 31.7 Gy, respectively, for VMAT plans and 37.7 and 37.6 Gy for 3D-CRT plans. This difference in mean temporal lobe dose resulted in an estimated IQ difference of 3.1 points at 5 years after radiation therapy. When the temporal lobes were explicitly included in the VMAT optimization, the mean temporal lobe dose was reduced 5.6-5.7 Gy, resulting in an estimated IQ difference of an additional 3 points. Reducing the ventricular margin from 1.5 cm to 0.5 cm decreased mean temporal lobe dose 11.4-13.1 Gy, corresponding to an estimated increase in IQ of 7 points. Conclusion: For treatment of children with intracranial pure germinomas, VMAT compared with 3D-CRT provides increased conformality and reduces doses to normal tissue. This may result in improvements in IQ in these children.

  3. The Effect of Dose-Volume Parameters and Interfraction Interval on Cosmetic Outcome and Toxicity After 3-Dimensional Conformal Accelerated Partial Breast Irradiation

    SciTech Connect (OSTI)

    Leonard, Kara Lynne, E-mail: karalynne.kerr@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Hepel, Jaroslaw T. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States) [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States)] [Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Dipetrillo, Thomas A. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States) [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Price, Lori Lyn [Department of Biostatistics Research Center, Institute of Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts (United States)] [Department of Biostatistics Research Center, Institute of Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts (United States); Wazer, David E. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States) [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States)

    2013-03-01T23:59:59.000Z

    Purpose: To evaluate dose-volume parameters and the interfraction interval (IFI) as they relate to cosmetic outcome and normal tissue effects of 3-dimensional conformal radiation therapy (3D-CRT) for accelerated partial breast irradiation (APBI). Methods and Materials: Eighty patients were treated by the use of 3D-CRT to deliver APBI at our institutions from 2003-2010 in strict accordance with the specified dose-volume constraints outlined in the National Surgical Adjuvant Breast and Bowel Project B39/Radiation Therapy Oncology Group 0413 (NSABP-B39/RTOG 0413) protocol. The prescribed dose was 38.5 Gy in 10 fractions delivered twice daily. Patients underwent follow-up with assessment for recurrence, late toxicity, and overall cosmetic outcome. Tests for association between toxicity endpoints and dosimetric parameters were performed with the chi-square test. Univariate logistic regression was used to evaluate the association of interfraction interval (IFI) with these outcomes. Results: At a median follow-up time of 32 months, grade 2-4 and grade 3-4 subcutaneous fibrosis occurred in 31% and 7.5% of patients, respectively. Subcutaneous fibrosis improved in 5 patients (6%) with extended follow-up. Fat necrosis developed in 11% of women, and cosmetic outcome was fair/poor in 19%. The relative volume of breast tissue receiving 5%, 20%, 50%, 80%, and 100% (V5-V100) of the prescribed dose was associated with risk of subcutaneous fibrosis, and the volume receiving 50%, 80%, and 100% (V50-V100) was associated with fair/poor cosmesis. The mean IFI was 6.9 hours, and the minimum IFI was 6.2 hours. The mean and minimum IFI values were not significantly associated with late toxicity. Conclusions: The incidence of moderate to severe late toxicity, particularly subcutaneous fibrosis and fat necrosis and resulting fair/poor cosmesis, remains high with continued follow-up. These toxicity endpoints are associated with several dose-volume parameters. Minimum and mean IFI values were not associated with late toxicity.

  4. Propensity Score-based Comparison of Long-term Outcomes With 3-Dimensional Conformal Radiotherapy vs Intensity-Modulated Radiotherapy for Esophageal Cancer

    SciTech Connect (OSTI)

    Lin, Steven H., E-mail: SHLin@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang Lu [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States)] [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Myles, Bevan [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Thall, Peter F. [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Hofstetter, Wayne L.; Swisher, Stephen G. [Department of Thoracic Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Thoracic Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Cox, James D.; Komaki, Ritsuko; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)] [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-12-01T23:59:59.000Z

    Purpose: Although 3-dimensional conformal radiotherapy (3D-CRT) is the worldwide standard for the treatment of esophageal cancer, intensity modulated radiotherapy (IMRT) improves dose conformality and reduces the radiation exposure to normal tissues. We hypothesized that the dosimetric advantages of IMRT should translate to substantive benefits in clinical outcomes compared with 3D-CRT. Methods and Materials: An analysis was performed of 676 nonrandomized patients (3D-CRT, n=413; IMRT, n=263) with stage Ib-IVa (American Joint Committee on Cancer 2002) esophageal cancers treated with chemoradiotherapy at a single institution from 1998-2008. An inverse probability of treatment weighting and inclusion of propensity score (treatment probability) as a covariate were used to compare overall survival time, interval to local failure, and interval to distant metastasis, while accounting for the effects of other clinically relevant covariates. The propensity scores were estimated using logistic regression analysis. Results: A fitted multivariate inverse probability weighted-adjusted Cox model showed that the overall survival time was significantly associated with several well-known prognostic factors, along with the treatment modality (IMRT vs 3D-CRT, hazard ratio 0.72, P<.001). Compared with IMRT, 3D-CRT patients had a significantly greater risk of dying (72.6% vs 52.9%, inverse probability of treatment weighting, log-rank test, P<.0001) and of locoregional recurrence (P=.0038). No difference was seen in cancer-specific mortality (Gray's test, P=.86) or distant metastasis (P=.99) between the 2 groups. An increased cumulative incidence of cardiac death was seen in the 3D-CRT group (P=.049), but most deaths were undocumented (5-year estimate, 11.7% in 3D-CRT vs 5.4% in IMRT group, Gray's test, P=.0029). Conclusions: Overall survival, locoregional control, and noncancer-related death were significantly better after IMRT than after 3D-CRT. Although these results need confirmation, IMRT should be considered for the treatment of esophageal cancer.

  5. Five-Year Outcomes, Cosmesis, and Toxicity With 3-Dimensional Conformal External Beam Radiation Therapy to Deliver Accelerated Partial Breast Irradiation

    SciTech Connect (OSTI)

    Rodríguez, Núria, E-mail: nrodriguez@parcdesalutmar.cat [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Sanz, Xavier [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Dengra, Josefa [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Foro, Palmira [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Membrive, Ismael; Reig, Anna [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Quera, Jaume [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Fernández-Velilla, Enric; Pera, Óscar; Lio, Jackson; Lozano, Joan [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Algara, Manuel [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain)

    2013-12-01T23:59:59.000Z

    Purpose: To report the interim results from a study comparing the efficacy, toxicity, and cosmesis of breast-conserving treatment with accelerated partial breast irradiation (APBI) or whole breast irradiation (WBI) using 3-dimensional conformal external beam radiation therapy (3D-CRT). Methods and Materials: 102 patients with early-stage breast cancer who underwent breast-conserving surgery were randomized to receive either WBI (n=51) or APBI (n=51). In the WBI arm, 48 Gy was delivered to the whole breast in daily fractions of 2 Gy, with or without additional 10 Gy to the tumor bed. In the APBI arm, patients received 37.5 Gy in 3.75 Gy per fraction delivered twice daily. Toxicity results were scored according to the Radiation Therapy Oncology Group Common Toxicity Criteria. Skin elasticity was measured using a dedicated device (Multi-Skin-Test-Center MC-750-B2, CKelectronic-GmbH). Cosmetic results were assessed by the physician and the patients as good/excellent, regular, or poor. Results: The median follow-up time was 5 years. No local recurrences were observed. No significant differences in survival rates were found. APBI reduced acute side effects and radiation doses to healthy tissues compared with WBI (P<.01). Late skin toxicity was no worse than grade 2 in either group, without significant differences between the 2 groups. In the ipsilateral breast, the areas that received the highest doses (ie, the boost or quadrant) showed the greatest loss of elasticity. WBI resulted in a greater loss of elasticity in the high-dose area compared with APBI (P<.05). Physician assessment showed that >75% of patients in the APBI arm had excellent or good cosmesis, and these outcomes appear to be stable over time. The percentage of patients with excellent/good cosmetic results was similar in both groups. Conclusions: APBI delivered by 3D-CRT to the tumor bed for a selected group of early-stage breast cancer patients produces 5-year results similar to those achieved with conventional WBI.

  6. Logarithmic Wind Profile: A Stability Wind Shear Term

    E-Print Network [OSTI]

    Sakagami, Yoshiaki; Haas, Reinaldo; Passos, Julio C; Taves, Frederico F

    2014-01-01T23:59:59.000Z

    A stability wind shear term of logarithmic wind profile based on the terms of turbulent kinetic energy equation is proposed. The fraction influenced by thermal stratification is considered in the shear production term. This thermally affected shear is compared with buoyant term resulting in a stability wind shear term. It is also considered Reynolds stress as a sum of two components associated with wind shear from mechanical and thermal stratification process. The stability wind shear is responsible to Reynolds stress of thermal stratification term, and also to Reynolds stress of mechanical term at no neutral condition. The wind profile and its derivative are validated with data from Pedra do Sal experiment in a flat terrain and 300m from shoreline located in northeast coast of Brazil. It is close to the Equator line, so the meteorological condition are strongly influenced by trade winds and sea breeze. The site has one 100m tower with five instrumented levels, one 3D sonic anemometer, and a medium-range wind...

  7. Multipole Formulae for Gravitational Lensing Shear and Flexion

    E-Print Network [OSTI]

    Gary M. Bernstein; Reiko Nakajima

    2008-07-11T23:59:59.000Z

    The gravitational lensing equations for convergence, potential, shear, and flexion are simple in polar coordinates and separate under a multipole expansion once the shear and flexion spinors are rotated into a ``tangential'' basis. We use this to investigate whether the useful monopole aperture-mass shear formulae generalize to all multipoles and to flexions. We re-derive the result of Schneider and Bartelmann that the shear multipole m at radius R is completely determined by the mass multipole at R, plus specific moments Q^m_in and Q^m_out of the mass multipoles internal and external, respectively, to R. The m>=0 multipoles are independent of Q_out. But in contrast to the monopole, the mmultipoles are independent of Q_in. These internal and external mass moments can be determined by shear (and/or flexion) data on the complementary portion of the plane, which has practical implications for lens modelling. We find that the ease of E/B separation in the monopole aperture moments does {\\em not} generalize to m!=0: the internal monopole moment is the {\\em only} non-local E/B discriminant available from lensing observations. We have also not found practical local E/B discriminants beyond the monopole, though they could exist. We show also that the use of weak-lensing data to constrain a constant shear term near a strong-lensing system is impractical without strong prior constraints on the neighboring mass distribution.

  8. Nonlinear physics of shear Alfvén waves

    SciTech Connect (OSTI)

    Zonca, Fulvio [Associazione EURATOM-ENEA sulla Fusione, C.P. 65-00044 Frascati, Italy and Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 31007 (China); Chen, Liu [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 31007, P.R.C. and Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

    2014-02-12T23:59:59.000Z

    Shear Alfvén waves (SAW) play fundamental roles in thermonuclear plasmas of fusion interest, since they are readily excited by energetic particles in the MeV range as well as by the thermal plasma components. Thus, understanding fluctuation induced transport in burning plasmas requires understanding nonlinear SAW physics. There exist two possible routes to nonlinear SAW physics: (i) wave-wave interactions and the resultant spectral energy transfer; (ii) nonlinear wave-particle interactions of SAW instabilities with energetic particles. Within the first route, it is advantageous to understand and describe nonlinear processes in term of proximity of the system to the Alfvénic state, where wave-wave interactions are minimized due to the cancellation of Reynolds and Maxwell stresses. Here, various wave-wave nonlinear dynamics are elucidated in terms of how they break the Alfvénic state. In particular, we discuss the qualitative and quantitative modification of the SAW parametric decay process due to finite ion compressibility and finite ion Larmor radius. We also show that toroidal geometry plays a crucial role in the nonlinear excitation of zonal structures by Alfvén eigenmodes. Within the second route, the coherent nonlinear dynamics of structures in the energetic particle phase space, by which secular resonant particle transport can occur on meso- and macro-scales, must be addressed and understood. These 'nonlinear equilibria' or 'phase-space zonal structures' dynamically evolve on characteristic (fluctuation induced) turbulent transport time scales, which are generally of the same order of the nonlinear time scale of the underlying fluctuations. In this work, we introduce the general structure of nonlinear Schrödinger equations with complex integro-differential nonlinear terms, which govern these physical processes. To elucidate all these aspects, theoretical analyses are presented together with numerical simulation results.

  9. The microstructure and rheology of a model, thixotropic nanoparticle gel under steady shear and large amplitude oscillatory shear (LAOS)

    SciTech Connect (OSTI)

    Min Kim, Jung; Kate Gurnon, A.; Wagner, Norman J., E-mail: wagnernj@udel.edu [Department of Chemical and Biomolecular Engineering and Center for Neutron Science, University of Delaware, Newark, Delaware 19716 (United States); Eberle, Aaron P. R. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Porcar, Lionel [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 and Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France)

    2014-09-01T23:59:59.000Z

    The microstructure-rheology relationship for a model, thermoreversible nanoparticle gel is investigated using a new technique of time-resolved neutron scattering under steady and time-resolved large amplitude oscillatory shear (LAOS) flows. A 21 vol. % gel is tested with varying strength of interparticle attraction. Shear-induced structural anisotropy is observed as butterfly scattering patterns and quantified through an alignment factor. Measurements in the plane of flow show significant, local anisotropy develops with alignment along the compressional axis of flow, providing new insights into how gels flow. The microstructure-rheology relationship is analyzed through a new type of structure-Lissajous plot that shows how the anisotropic microstructure is responsible for the observed LAOS response, which is beyond a response expected for a purely viscous gel with constant structure. The LAOS shear viscosities are observed to follow the “Delaware-Rutgers” rule. Rheological and microstructural data are successfully compared across a broad range of conditions by scaling the shear rate by the strength of attraction, providing a method to compare behavior between steady shear and LAOS experiments. However, important differences remain between the microstructures measured at comparatively high frequency in LAOS experiments and comparable steady shear experiments that illustrate the importance of measuring the microstructure to properly interpret the nonlinear, dynamic rheological response.

  10. Low work function material development for the microminiature thermionic converter.

    SciTech Connect (OSTI)

    Zavadil, Kevin Robert; Battaile, Corbett Chandler; Marshall, Albert Christian; King, Donald Bryan; Jennison, Dwight Richard

    2004-03-01T23:59:59.000Z

    Thermionic energy conversion in a miniature format shows potential as a viable, high efficiency, micro to macro-scale power source. A microminiature thermionic converter (MTC) with inter-electrode spacings on the order of microns has been prototyped and evaluated at Sandia. The remaining enabling technology is the development of low work function materials and processes that can be integrated into these converters to increase power production at modest temperatures (800 - 1300 K). The electrode materials are not well understood and the electrode thermionic properties are highly sensitive to manufacturing processes. Advanced theoretical, modeling, and fabrication capabilities are required to achieve optimum performance for MTC diodes. This report describes the modeling and fabrication efforts performed to develop micro dispenser cathodes for use in the MTC.

  11. Process for converting cellulosic materials into fuels and chemicals

    DOE Patents [OSTI]

    Scott, C.D.; Faison, B.D.; Davison, B.H.; Woodward, J.

    1994-09-20T23:59:59.000Z

    A process is described for converting cellulosic materials, such as waste paper, into fuels and chemicals utilizing enzymatic hydrolysis of the major constituent of paper, cellulose. A waste paper slurry is contacted by cellulase in an agitated hydrolyzer. The cellulase is produced from a continuous, columnar, fluidized-bed bioreactor utilizing immobilized microorganisms. An attrition mill and a cellobiase reactor are coupled to the agitated hydrolyzer to improve reaction efficiency. The cellulase is recycled by an adsorption process. The resulting crude sugars are converted to dilute product in a fluidized-bed bioreactor utilizing microorganisms. The dilute product is concentrated and purified by utilizing distillation and/or a biparticle fluidized-bed bioreactor system. 1 fig.

  12. Planar LTCC transformers for high voltage flyback converters: Part II.

    SciTech Connect (OSTI)

    Schofield, Daryl (NASCENTechnology, Inc., Watertown, SD); Schare, Joshua M., Ph.D.; Slama, George (NASCENTechnology, Inc., Watertown, SD); Abel, David (NASCENTechnology, Inc., Watertown, SD)

    2009-02-01T23:59:59.000Z

    This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material properties and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.

  13. Discharging a DC bus capacitor of an electrical converter system

    DOE Patents [OSTI]

    Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

    2014-10-14T23:59:59.000Z

    A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

  14. Development, evaluation, and design applications of an AMTEC converter model

    E-Print Network [OSTI]

    Spence, Cliff Alan

    2002-01-01T23:59:59.000Z

    of performance curves . . . . . . . 90 INTRODUCTION In the recent history of space exploration, space vehicles slated for missions that ventured into deep space, far from the sun, typically relied on Radioisotope Thermoelectric Generator (RTG) power sources... this need is a type of generator that uses technology known as alkali metal thermal-to-electric conversion (AMTEC). This device, like previous thermoelectric power systems, converts thermal energy directly to electricity. Developed at Ford Scientific...

  15. Capacitor-Less VAR Compensator Based on a Matrix Converter

    E-Print Network [OSTI]

    Balakrishnan, Divya Rathna

    2012-02-14T23:59:59.000Z

    greatly contributed to the completion of this work. I owe my gratitude to them for always believing in me and helping me through my academic pursuit. vii NOMENCLATURE VAR Volt-ampere reactive MC 3-phase ac-to-3-phase ac matrix converter v1... [10] ...... 12 10 Equivalent circuit of a capacitor................................................................. 13 11 Basic layout of a 3/3 MC............................................................................ 16 12 Block diagram...

  16. Low current plasmatron fuel converter having enlarged volume discharges

    DOE Patents [OSTI]

    Rabinovich, Alexander (Swampscott, MA); Alexeev, Nikolai (Moscow, RU); Bromberg, Leslie (Sharon, MA); Cohn, Daniel R. (Chestnut Hill, MA); Samokhin, Andrei (Moscow, RU)

    2009-10-06T23:59:59.000Z

    A novel apparatus and method is disclosed for a plasmatron fuel converter ("plasmatron") that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.

  17. Intensive neutrino source on the base of lithium converter

    E-Print Network [OSTI]

    V. I. Lyashuk; Yu. S Lutostansky

    2015-04-13T23:59:59.000Z

    An intensive antineutrino source with a hard spectrum (with energy up to 13 MeV, average energy 6.5 MeV) can be realized on the base of beta-decay of short living isotope 8Li (0.84 s). The 8Li isotope (generated in activation of 7Li isotope) is a prime perspective antineutrino source owing to the hard antineutrino spectrum and square dependence of cross section on the energy. Up today nuclear reactors are the most intensive neutrino sources. Antineutrino reactor spectra have large uncertainties in the summary antineutrino spectrum at energy E>6 MeV. Use of 8Li isotope allows to decrease sharply the uncertainties or to exclude it completely. An intensive neutron fluxes are requested for rapid generation of 8Li isotope. The installations on the base of nuclear reactors can be an alternative for nuclear reactors as traditional neutron sources. It is possible creation of neutrino sources another in principle: on the base of tandem of accelerators, neutron generating targets and lithium converter. An intensive neutron flux (i.e., powerful neutron source) is requested for realization of considered neutrino sources (neutrino factories). Different realizations of lithium antineutrino sources (lithium converter on the base of high purified 7Li isotope) are discussed: static regime (i.e., without transport of 8Li isotope to the neutrino detector); dynamic regime (transport of 8Li isotope to the remote detector in a closed cycle); an operation of lithium converter in tandem of accelerator with a neutron-producing target on the base of tungsten, lead or bismuth. Different chemical compounds of lithium (as the substance of the converter) are considered. Heavy water solution of LiOD is proposed as a serious alternative to high-pure 7Li in a metallic state.

  18. Low current plasmatron fuel converter having enlarged volume discharges

    DOE Patents [OSTI]

    Rabinovich, Alexander; Alexeev, Nikolai; Bromberg, Leslie; Cohn, Daniel R.; Samokhin, Andrei

    2005-04-19T23:59:59.000Z

    A novel apparatus and method is disclosed for a plasmatron fuel converter (""plasmatron"") that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.

  19. Liquid Metal Thermal Electric Converter bench test module

    SciTech Connect (OSTI)

    Lukens, L.L.; Andraka, C.E.; Moreno, J.B.

    1988-04-01T23:59:59.000Z

    This report describes the design, fabrication, and test of a Liquid Metal Thermal Electric Converter Bench Test Module. The work presented in this document was conducted as a part of Heat Engine Task of the US Department of Energy's (DOE) Solar Thermal Technology Program. The objective of this task is the development and evaluation of heat engine technologies applicable to distributed receiver systems, in particular, dish electric systems.

  20. Intensive neutrino source on the base of lithium converter

    E-Print Network [OSTI]

    V. I. Lyashuk; Yu. S Lutostansky

    2015-03-04T23:59:59.000Z

    An intensive antineutrino source with a hard spectrum (with energy up to 13 MeV, average energy 6.5 MeV) can be realized on the base of beta-decay of short living isotope 8Li (0.84 s). The 8Li isotope (generated in activation of 7Li isotope) is a prime perspective antineutrino source owing to the hard antineutrino spectrum and square dependence of cross section on the energy. Up today nuclear reactors are the most intensive neutrino sources. Antineutrino reactor spectra have large uncertainties in the summary antineutrino spectrum at energy E>6 MeV. Use of 8Li isotope allows to decrease sharply the uncertainties or to exclude it completely. An intensive neutron fluxes are requested for rapid generation of 8Li isotope. The installations on the base of nuclear reactors can be an alternative for nuclear reactors as traditional neutron sources. It is possible creation of neutrino sources another in principle: on the base of tandem of accelerators, neutron generating targets and lithium converter. An intensive neutron flux (i.e., powerful neutron source) is requested for realization of considered neutrino sources (neutrino factories). Different realizations of lithium antineutrino sources (lithium converter on the base of high purified 7Li isotope) are discussed: static regime (i.e., without transport of 8Li isotope to the neutrino detector); dynamic regime (transport of 8Li isotope to the remote detector in a closed cycle); an operation of lithium converter in tandem of accelerator with a neutron-producing target on the base of tungsten, lead or bismuth. Different chemical compounds of lithium (as the substance of the converter) are considered. Heavy water solution of LiOD is proposed as a serious alternative to high-pure 7Li in a metallic state.

  1. Catalyst for converting synthesis gas to liquid motor fuels

    DOE Patents [OSTI]

    Coughlin, Peter K. (Yorktown Heights, NY)

    1986-01-01T23:59:59.000Z

    The addition of an inert metal component, such as gold, silver or copper, to a Fischer-Tropsch catalyst comprising cobalt enables said catalyst to convert synthesis gas to liquid motor fuels at about 240.degree.-370.degree. C. with advantageously reduced selectivity of said cobalt for methane in said conversion. The catalyst composition can advantageously include a support component, such as a molecular sieve, co-catalyst/support component or a combination of such support components.

  2. Shear Waves, Sound Waves On A Shimmering Horizon

    E-Print Network [OSTI]

    Omid Saremi

    2007-03-19T23:59:59.000Z

    In the context of the so called ``membrane paradigm'' of black holes/branes, it has been known for sometime that the dynamics of small fluctuations on the stretched horizon can be viewed as corresponding to diffusion of a conserved charge in simple fluids. To study shear waves in this context properly, one must define a conserved stress tensor living on the stretched horizon. Then one is required to show that such a stress tensor satisfies the corresponding constitutive relations. These steps are missing in a previous treatment of the shear perturbations by Kovtun, Starinets and Son. In this note, we fill the gap by prescribing the stress tensor on the stretched horizon to be the Brown and York (or Balasubramanian-Kraus (BK) in the AdS/CFT context) holographic stress tensor. We are then able to show that such a conserved stress tensor satisfies the required constitutive relation on the stretched horizon using Einstein equations. We read off the shear viscosity from the constitutive relations in two different channels, shear and sound. We find an expression for the shear viscosity in both channels which are equal, as expected. Our expression is in agreement with a previous membrane paradigm formula reported by Kovtun, Starinets and Son.

  3. Shear strength of ice rubble in laboratory tests

    SciTech Connect (OSTI)

    Lehmus, E.; Kaernae, T.

    1995-12-31T23:59:59.000Z

    The values of shear strength of the ice rubble in the ridge keels and rubble fields are important in force computations. To increase the data on ridge properties, the shear strength of partially consolidated ice rubble was studied by making tests in a shear box. The only variable was the consolidation time. The tests were done in a simple shear box in which the top and bottom of the ice are not confined. The dimensions of the box were 0.96 m in length, 0.8 m in width and 0.8 m in height. The upper part of the box was pulled with the carriage. The ice field was sawn in blocks in order to get a controlled block size distribution. The size distribution for the ice blocks was selected to correspond published data on full-scale ice ridges. The measured mean values of shear strength varied from 1 kPa to 17 kPa depending on the freezing conditions.

  4. Particle acceleration in rotating and shearing jets from AGN

    E-Print Network [OSTI]

    F. M. Rieger; K. Mannheim

    2002-10-14T23:59:59.000Z

    We model the acceleration of energetic particles due to shear and centrifugal effects in rotating astrophysical jets. The appropriate equation describing the diffusive transport of energetic particles in a collisionless, rotating background flow is derived and analytical steady state solutions are discussed. In particular, by considering velocity profiles from rigid, over flat to Keplerian rotation, the effects of centrifugal and shear acceleration of particles scattered by magnetic inhomogeneities are distinguished. In the case where shear acceleration dominates, it is confirmed that power law particle momentum solutions $f(p) \\propto p^{-(3+\\alpha)}$ exist, if the mean scattering time $\\tau_c \\propto p^{\\alpha}$ is an increasing function of momentum. We show that for a more complex interplay between shear and centrifugal acceleration, the recovered power law momentum spectra might be significantly steeper but flatten with increasing azimuthal velocity due to the increasing centrifugal effects. The possible relevance of shear and centrifugal acceleration for the observed extended emission in AGN is demonstrated for the case of the jet in the quasar 3C273.

  5. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    design optimization of wave energy converters con- sistingN. Sahinkaya. A review of wave energy converter technology.2009. [6] A.F.O. Falc˜ao. Wave energy utilization: A review

  6. Blind calibration of timing skew in time-interleaved analog-to-digital converters

    E-Print Network [OSTI]

    Divi, Vijay

    The performance of time-interleaved analog-to-digital converters is often significantly degraded by timing mismatch errors. We develop methods for performing blind calibration of such converters, i.e., for estimating the ...

  7. Computer-aided optimization of DC/DC converters for automotive applications

    E-Print Network [OSTI]

    Neugebauer, Timothy C.

    This paper investigates computer-aided optimization of DC/DC converters, with a focus on converters for dual-voltage automotive electrical systems. A new CAD optimization approach based on Monte Carlo search methods is ...

  8. CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland

    E-Print Network [OSTI]

    Haller, Merrick

    CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland ABSTRACT Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms at station 139. Keywords: wave energy, survivability, breaking waves, joint distribution, OWEC INTRODUCTION

  9. Characterization of U.S. Wave Energy Converter Test Sites: A...

    Energy Savers [EERE]

    Characterization of U.S. Wave Energy Converter Test Sites: A Catalogue of Met-Ocean Data Characterization of U.S. Wave Energy Converter Test Sites: A Catalogue of Met-Ocean Data...

  10. Report of the DOD-DOE Workshop on Converting Waste to Energy...

    Office of Environmental Management (EM)

    DOD-DOE Workshop on Converting Waste to Energy Using Fuel Cells: Workshop Summary and Action Plan Report of the DOD-DOE Workshop on Converting Waste to Energy Using Fuel Cells:...

  11. Effects of cyclic loading on internal shear strength of unreinforced geosynthetic clay liner

    SciTech Connect (OSTI)

    Lai, J. [Ghaoyang Univ. of Technology, Taichung (Taiwan, Province of China); Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States). Dept. of Civil Engineering; Wright, S.G. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

    1998-01-01T23:59:59.000Z

    Stress-controlled static and cyclic shear tests were performed by using a direct simple shear device on samples of a geomembrane-supported geosynthetic clay liner (GCL). The dry material showed no degradation in shear strength during cyclic loading as long as the peak shear stress was less than the static shear strength of the GCL with no cyclic loading. Furthermore, cyclic loading slightly densified the dry bentonite and thus increased its shear resistance under subsequent static loading. On the other hand, the shear strength of the hydrated GCL was found to be reduced by cyclic loading. The number of cycles to cause failure decreased with increasing cyclic stress ratio (cyclic shear stress divided by undrained static shear strength); at a cyclic stress ratio of 0.67, failure occurred at 32 cycles of loading, but at a cyclic stress ratio of 0.53, failure did not occur until up to 200 cycles of loading.

  12. Comparison between arc drops in ignited thermionic converters with and without ion reflections at the emitter

    SciTech Connect (OSTI)

    Lundgren, L.

    1985-07-01T23:59:59.000Z

    The output performance of two thermionic energy converters is compared. One converter has a normal emitter, working with zero field at the emitter which is close to the optimum working point, and the other has a low work function emitter and ion reflection at the emitter. A simple model of the plasma and the sheaths shows that a converter working with a low work function emitter and ion reflections gives a worse performance than a similar converter with a normal emitter.

  13. Reentry aerodynamic disruption analysis of thermionic reactor-thermo-converter TOPAZ-2

    SciTech Connect (OSTI)

    Grinberg, E.I.; Nikolaev, V.S. (Scientific Production Association Krasnaya Zvezda'', Moscow 115230 (Russian Federation)); Usov, V.A. (RRC Kurchatov Institute'', Moscow 123182 (Russian Federation)); Gafarov, A.A. (Research Institute of Thermal Processes, Moscow (Russian Federation))

    1993-01-15T23:59:59.000Z

    This paper presents preliminary results of analysis for the TOPAZ-2 thermionic converter-reactor aerodynamic disruption during reentry.

  14. Combined Ideal and Kinetic Effects on Reversed Shear Alfven Eigenmodes

    SciTech Connect (OSTI)

    N.N. Gorelenkov, G.J. Kramer, and R. Nazikian

    2011-05-23T23:59:59.000Z

    A theory of Reversed Shear Alfven Eigenmodes (RSAEs) is developed for reversed magnetic field shear plasmas when the safety factor minimum, qmin, is at or above a rational value. The modes we study are known sometimes as either the bottom of the frequency sweep or the down sweeping RSAEs. We show that the ideal MHD theory is not compatible with the eigenmode solution in the reversed shear plasma with qmin above integer values. Corrected by special analytic FLR condition MHD dispersion of these modes nevertheless can be developed. Large radial scale part of the analytic RSAE solution can be obtained from ideal MHD and expressed in terms of the Legendre functions. The kinetic equation with FLR effects for the eigenmode is solved numerically and agrees with the analytic solutions. Properties of RSAEs and their potential implications for plasma diagnostics are discussed.

  15. Collective rheology in quasi static shear flow of granular media

    E-Print Network [OSTI]

    Tamás Unger

    2010-09-20T23:59:59.000Z

    This paper is devoted to the basic question of what factors determine the strain field in a quasi static granular flow. It is shown that using stress - strain rate relations is not the proper way to understand quasi static rheology. An alternative approach is discussed where the local deformation is regarded as the cause of deformation in the vicinity. We suggest a continuum model where the local shear strain is proportional to its Laplacian and the proportionality factor is determined by the local stress. The predicted behavior is tested in a three dimensional shear cell by means of computer simulations. The simplicity of our setup makes it ideal to demonstrate and examine the fundamental open questions of collective granular flows. The observed shear profile is interpreted in the framework of the suggested model.

  16. Anomalous diffusion of proteins in sheared lipid membranes

    E-Print Network [OSTI]

    Khoshnood, Atefeh

    2013-01-01T23:59:59.000Z

    We use coarse grained molecular dynamics simulations to investigate diffusion properties of sheared lipid membranes with embedded transmembrane proteins. In membranes without proteins, we find normal in-plane diffusion of lipids in all flow conditions. Protein embedded membranes behave quite differently: by imposing a simple shear flow and sliding the monolayers of the membrane over each other, the motion of protein clusters becomes strongly superdiffusive in the shear direction. In such a circumstance, subdiffusion regime is predominant perpendicular to the flow. We show that superdiffusion is a result of accelerated chaotic motions of protein--lipid complexes within the membrane voids, which are generated by hydrophobic mismatch or the transport of lipids by proteins.

  17. Transverse electron-scale instability in relativistic shear flows

    E-Print Network [OSTI]

    Alves, E P; Fonseca, R A; Silva, L O

    2015-01-01T23:59:59.000Z

    Electron-scale surface waves are shown to be unstable in the transverse plane of a shear flow in an initially unmagnetized plasma, unlike in the (magneto)hydrodynamics case. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroom-like electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. Macroscopic ($\\gg c/\\omega_{pe}$) fields are shown to be generated by these microscopic shear instabilities, which are relevant for particle acceleration, radiation emission and to seed MHD processes at long time-scales.

  18. Quasiparticle theory of shear and bulk viscosities of hadronic matter

    SciTech Connect (OSTI)

    Chakraborty, P.; Kapusta, J. I. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2011-01-15T23:59:59.000Z

    A theoretical framework for the calculation of shear and bulk viscosities of hadronic matter at finite temperature is presented. The framework is based on the quasiparticle picture. It allows for an arbitrary number of hadron species with pointlike interactions, and allows for both elastic and inelastic collisions. Detailed balance is ensured. The particles have temperature-dependent masses arising from mean-field or potential effects, which maintains self-consistency between the equation of state and the transport coefficients. As an example, we calculate the shear and bulk viscosity in the linear {sigma} model. The ratio of shear viscosity to entropy density shows a minimum in the vicinity of a rapid crossover transition, whereas the ratio of bulk viscosity to entropy density shows a maximum.

  19. Predictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Predictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters M.S. Lagoun1. There are several wave energy converters to harness this energy. Some of them, as in tidal applications, use of a DFIG-based Wave Energy Converter (WEC). In the proposed control approach, the predicted output power

  20. A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter

    E-Print Network [OSTI]

    Brest, Université de

    A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter in Irregular there are several wave energy converters to harness this energy. Some of them, as in tidal applications, use based Wave Energy Converter under irregular wave climate which is modeled as time series elevation from

  1. Modeling and Analysis of Hybrid Converters Michael Evzelman Shmuel (Sam) Ben-Yaakov

    E-Print Network [OSTI]

    the characteristics of hybrid converters. Renewable energy sources such as a single PV panel have, in general, a lowModeling and Analysis of Hybrid Converters Michael Evzelman Shmuel (Sam) Ben-Yaakov Power.ee.bgu.ac.il/~pel/ Abstract--A generic behavioral average-circuit model that analyzes hybrid converters that include

  2. Design techniques for low noise and high speed A/D converters

    E-Print Network [OSTI]

    Gupta, Amit Kumar

    2009-05-15T23:59:59.000Z

    . The resolution and sampling rate of an A/D converter vary depending on the application. Recently, there has been a growing demand for broadband (>1 MHz), high-resolution (>14bits) A/D converters. Applications that demand such converters include asymmetric digital...

  3. High Efficiency Interleaved Power Electronics Converter for wide operating power range

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    High Efficiency Interleaved Power Electronics Converter for wide operating power range K driving strategy for improving the efficiency of power converters even if they are not used is presented. Index Terms-Power converters, Interleaved, Power efficiency I. CONTEXTE, INTRODUCTION One

  4. Design techniques for low noise and high speed A/D converters 

    E-Print Network [OSTI]

    Gupta, Amit Kumar

    2009-05-15T23:59:59.000Z

    . The resolution and sampling rate of an A/D converter vary depending on the application. Recently, there has been a growing demand for broadband (>1 MHz), high-resolution (>14bits) A/D converters. Applications that demand such converters include asymmetric digital...

  5. Development of a 55 kW 3X DC-DC Converter for HEV Systems

    E-Print Network [OSTI]

    Tolbert, Leon M.

    converter and a traction motor to drive the vehicle. In most commercial HEV systems, the power converter one of the hottest parts in the system. Hence, with the trend of higher coolant temperatures, those-dc converter and the continuous control of the modulation index of the inverter, it is sufficient to operate

  6. Shear Strength Measurement Benchmarking Tests for K Basin Sludge Simulants

    SciTech Connect (OSTI)

    Burns, Carolyn A.; Daniel, Richard C.; Enderlin, Carl W.; Luna, Maria; Schmidt, Andrew J.

    2009-06-10T23:59:59.000Z

    Equipment development and demonstration testing for sludge retrieval is being conducted by the K Basin Sludge Treatment Project (STP) at the MASF (Maintenance and Storage Facility) using sludge simulants. In testing performed at the Pacific Northwest National Laboratory (under contract with the CH2M Hill Plateau Remediation Company), the performance of the Geovane instrument was successfully benchmarked against the M5 Haake rheometer using a series of simulants with shear strengths (?) ranging from about 700 to 22,000 Pa (shaft corrected). Operating steps for obtaining consistent shear strength measurements with the Geovane instrument during the benchmark testing were refined and documented.

  7. Scaling of the magnetic reconnection rate with symmetric shear flow

    SciTech Connect (OSTI)

    Cassak, P. A. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Otto, A. [Geophysical Institute, University of Alaska-Fairbanks, Fairbanks, Alaska 99775 (United States)

    2011-07-15T23:59:59.000Z

    The scaling of the reconnection rate during (fast) Hall magnetic reconnection in the presence of an oppositely directed bulk shear flow parallel to the reconnecting magnetic field is studied using two-dimensional numerical simulations of Hall reconnection with two different codes. Previous studies noted that the reconnection rate falls with increasing flow speed and shuts off entirely for super-Alfvenic flow, but no quantitative expression for the reconnection rate in sub-Alfvenic shear flows is known. An expression for the scaling of the reconnection rate is presented.

  8. Thermonuclear Fusion with the Sheared Flow Stabilized Z-Pinch

    E-Print Network [OSTI]

    Winterberg, F

    2008-01-01T23:59:59.000Z

    Two basic approaches to producing thermonuclear fusion with a sheared flow stabilized z-pinch are considered. One consists of heating the entire length of the z-pinch column to the required temperatures. The other basic approach considered here involves the concept of fast ignition. A localized "hot-spot" is produced under the proper conditions to ignite a thermonuclear burn wave in the z-pinch plasma. Here we demonstrate that sheared flow stabilization is more efficient in the fast-ignition method with isentropic compression then in a z-pinch where the entire plasma column is heated.

  9. Shear zone refraction and deflection in layered granular materials

    E-Print Network [OSTI]

    Tamas Borzsonyi; Tamas Unger; Balazs Szabo

    2009-12-09T23:59:59.000Z

    Refraction and deflection of shear zones in layered granular materials was studied experimentally and numerically. We show, that (i) according to a recent theoretical prediction [T. Unger, Phys. Rev. Lett. 98, 018301 (2007)] shear zones refract in layered systems in analogy with light refraction, (ii) zone refraction obeys Snell's law known from geometric optics and (iii) under natural pressure conditions (i.e. in the presence of gravity) the zone can also be deflected by the interface so that the deformation of the high friction material is avoided.

  10. The evolution of the shear viscosity away from unitarity

    E-Print Network [OSTI]

    Gabriel Wlaz?owski; Wei Quan; Aurel Bulgac

    2015-04-10T23:59:59.000Z

    We present an it ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength 1/ak_F from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for 1/ak_F approx 0.4.

  11. The evolution of the shear viscosity away from unitarity

    E-Print Network [OSTI]

    Wlaz?owski, Gabriel; Bulgac, Aurel

    2015-01-01T23:59:59.000Z

    We present an it ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength 1/ak_F from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for 1/ak_F approx 0.4.

  12. Nonlinear FE analysis of cracks in tension and shear

    E-Print Network [OSTI]

    Kesse, G.; Lees, Janet M.

    2007-05-01T23:59:59.000Z

    Carbon FRP Shear Reinforcement. PhD thesis, University of Cambridge, UK, 2003. 3. Bazant Z. P. and Planas J. Fracture and Size Effect in Con- crete and Other Quasibrittle Materials. CRC Press, Boca Raton, Florida, 1998. Nonlinear FE analysis of cracks... of plain concrete to cyclic tension. ACI Materials Journal, 1987, 84, No. 5, 365–373. 9. Paulay T. and Loeber P. J. Shear transfer by aggregate inter- lock. ACI Special Publication, SP-42, 1974, 1, 1–14. 10. Houde J. and Mirza M. S. A finite element...

  13. Design and analysis of modern three-phase AC/AC power converters for AC drives and utility interface 

    E-Print Network [OSTI]

    Kwak, Sangshin

    2005-08-29T23:59:59.000Z

    Significant advances in modern ac/ac power converter technologies and demands of industries have reached beyond standard ac/ac power converters with voltage-source inverters fed from diode rectifiers. Power electronics converters have been matured...

  14. The mathematical structure of theories of resource convertibility I

    E-Print Network [OSTI]

    Tobias Fritz

    2015-04-14T23:59:59.000Z

    Resources and their use and consumption form a central part of our life. Many branches of science and engineering are concerned with the question of which given resource objects can be converted into which target resource objects. For example, information theory studies the conversion of a noisy communication channel instance into an exchange of information. Inspired by work in quantum information theory, we develop a general framework for this type of question. The convertibility of resources into other ones and the possibility of combining resources is accurately captured by the mathematics of ordered commutative monoids. As an intuitive example, we consider chemistry, where chemical reaction equations such as $\\mathrm{2H_2 + O_2} \\longrightarrow \\mathrm{2H_2O}$ are concerned both with a convertibility relation $\\longrightarrow$ and a combination operation $+$. We study ordered commutative monoids from an algebraic and functional-analytic perspective and derive a wealth of results which should have applications to concrete resource theories, such as a formula for rates of conversion. As a running example showing that ordered commutative monoids are also of purely mathematical interest, we exemplify our results with the ordered commutative monoid of graphs. While closely related to both Girard's linear logic and Deutsch's constructor theory, our framework also produces results very reminiscent of the utility theorem of von Neumann and Morgenstern in decision theory and of a theorem of Lieb and Yngvason on thermodynamics. Concerning pure algebra, our observation is that some pieces of algebra can be developed in a context in which equality is not necessarily symmetric, i.e. in which the equality relation is replaced by an ordering relation. For example, notions like cancellativity or torsion-freeness are still sensible and very natural concepts in our ordered setting.

  15. Design and testing of a combustion-heated nineteen-converter SAVTEC array

    SciTech Connect (OSTI)

    Nyren, T.; Fitzpatrick, G.O.; Korringa, M.; McVey, J.; Sahines, T.

    1984-08-01T23:59:59.000Z

    The SAVTEC (Self-Adjusting Versatile Thermionic Energy Converter) is a new design approach for achieving very close (<12..mu..) interelectrode spacing in a thermionic converter. Techniques were developed for fabricating an array of nineteen SAVTEC converters. The array was incorporated in an SiC protective ''hot shell'' which also served as a radiant heat source for the emitter of each converter. The completed assembly was tested with a specially constructed combustion heat source. Electric output was generated by sixteen of the nineteen converters, despite poor thermal contact in a cooling block, which resulted in high collector temperatures. Details of the array design and test results are described.

  16. Experimental investigation of a thermionic converter with developed surface electrodes

    SciTech Connect (OSTI)

    Luke, James R.; El-Genk, Mohamed S.; Adrian, John M. [Institute for Space and Nuclear Power Studies/Chemical and Nuclear Engineering Department University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    1997-01-10T23:59:59.000Z

    A thermionic converter with developed planar electrode surfaces is designed and tested. One of the electrodes has concentric circular grooves cut into its surface, while the other electrode surface is smooth. The grooves are 0.5 mm deep and 0.5 mm wide, having lands that are 1.0 mm wide. The experimental setup is flexible so that either the smooth or developed surface electrode can be operated as the emitter, with the other operating as the collector. The I-V characteristics and power output are compared for the two electrode arrangements.

  17. Experimental investigation of a thermionic converter with developed surface electrodes

    SciTech Connect (OSTI)

    Luke, J.R.; El-Genk, M.S.; Adrian, J.M. [Institute for Space and Nuclear Power Studies/Chemical and Nuclear Engineering Department University of New Mexico, Albuquerque, New Mexico87131 (United States)

    1997-01-01T23:59:59.000Z

    A thermionic converter with developed planar electrode surfaces is designed and tested. One of the electrodes has concentric circular grooves cut into its surface, while the other electrode surface is smooth. The grooves are 0.5 mm deep and 0.5 mm wide, having lands that are 1.0 mm wide. The experimental setup is flexible so that either the smooth or developed surface electrode can be operated as the emitter, with the other operating as the collector. The I-V characteristics and power output are compared for the two electrode arrangements. {copyright} {ital 1997 American Institute of Physics.}

  18. Multichannel analog-digital converter in VEKTOR-CAMAC systemsystems

    SciTech Connect (OSTI)

    Borodyanskii, M.E.

    1986-09-01T23:59:59.000Z

    This paper describes a four-channel analog-digital converter (ADC) that is implemented by large-scale integrated circuits. Resdundancy of signal conversion in intermediate cycles ensures a more accurate conversion result from cycle to cycle. The ADC is fully compatible with the Vektor system and, with slight modifications, is CAMAC compatible. The conversion time of the ADC for one channel is 5 used, the output code is 14-bit binary, the maximum integral nonlinearity is not more than 0.05% of the dynamic range of + or -10V, and the size of the random access memeory is 1024 14-bit words.

  19. Close-spaced Knudsen`s mode thermionic converter

    SciTech Connect (OSTI)

    Kucherov, R.Ya.; Nikolaev, Y.V. [Research Inst. of SIA Lutch, Podolsk (Russian Federation)

    1995-12-31T23:59:59.000Z

    It is demonstrated that the Knudsen`s mode of the thermionic converter (TIC) operation can be realized in a TIC with the interelectrode spacing 15{divided_by}30 {mu} and the emitter work function 5{divided_by}5.5 eV at the emitter temperature above 1800 K and cesium vapor pressure 0.5{divided_by}1 tor. With the use of reflective coating applied to the collector, efficiency of such TIC can achieve the level in excess of 30%.

  20. Results from the Microminiature Thermionic Converter Demonstration Testing Program

    SciTech Connect (OSTI)

    King, D.B.; Luke, J.R.; Wyant, F.J.

    1998-10-05T23:59:59.000Z

    Research is in progress to develop microminiature thermionic converters (MTCS) with high energy conversion efficiencies and variable operating temperatures using semiconductor integrated circuit (IC) fabrication methods. The use of IC techniques allows the fabrication of MTCS with cathode to anode spacing of several microns or less and with anode and cathode materials that will have work fimctions ranging from 1 eV to 3 eV. The small cathode to anode spacing and variable electrode work functions should allow the conversion of heat energy to relatively large current densities (up to tens of Amps/cmz) at relatively high conversion efficiencies ( 15-25%).

  1. Light-weight DC to very high voltage DC converter

    DOE Patents [OSTI]

    Druce, Robert L. (Union City, CA); Kirbie, Hugh C. (Dublin, CA); Newton, Mark A. (Livermore, CA)

    1998-01-01T23:59:59.000Z

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

  2. Light-weight DC to very high voltage DC converter

    DOE Patents [OSTI]

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30T23:59:59.000Z

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  3. Use of a combined lining in copper production converters

    SciTech Connect (OSTI)

    Birkle, G.V.B.; Slovikovski, V.V.; Danilova, T.A.; P'yankova, V.A.; Verzilov, N.A.

    1987-01-01T23:59:59.000Z

    The authors look at materials and methods for increasing the liner life and thermal efficiency of converters used at three copper melting combines in the Soviet Union. The refractories tested are various commercial combinations of magnesite, periclase and chromite, and the properties for which they are tested include their compression strength, heat resistance, thermal expansion, and wear resistance to slag. The authors find the refractory combination least degradable by heat and wear and calculate the savings, both in cost and energy, achieved by the combines in question by the utilization of this liner material.

  4. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect (OSTI)

    Abas Goodarzi

    2011-01-31T23:59:59.000Z

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  5. Performance testing of the Sandy Pond HVDC converter terminal

    SciTech Connect (OSTI)

    Donahue, J.A.; Fisher, D.A.; Railing, B.D.; Tatro, P.J. (New England Power Service Co., Westborough, MA (United States))

    1993-01-01T23:59:59.000Z

    Results of several performance tests for the 1,800 MW Sandy Pond HVDC converter terminal are presented and discussed. The work progressed during 1990 and 1991 and included tests for power line carrier interference, audible sound, ac and dc line faults and dc harmonic performance. The testing was conducted as part of the commissioning program for the first stage of the Quebec-New England Phase 2 multi-terminal system. In this stage, the Radisson (Quebec) and Sandy Pond (New England) terminals are operational.

  6. Optimal design of AC filter circuits in HVDC converter stations

    SciTech Connect (OSTI)

    Saied, M.M.; Khader, S.A. [Kuwait Univ. (Kuwait). Electrical and Computer Engineering Dept.

    1995-12-31T23:59:59.000Z

    This paper investigates the reactive power as well as the harmonic conditions on both the valve and the AC-network sides of a HVDC converter station. The effect of the AC filter circuits is accurately modeled. The program is then augmented by adding an optimization routine. It can identify the optimal filter configuration, yielding the minimum current distortion factor at the AC network terminals for a prespecified fundamental reactive power to be provided by the filter. Several parameter studies were also conducted to illustrate the effect of accidental or intentional deletion of one of the filter branches.

  7. Harmonic measurements from a group connected generator HVdc converter scheme

    SciTech Connect (OSTI)

    Macdonald, S.J.; Enright, W.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand); O`Brien, M.T.

    1995-10-01T23:59:59.000Z

    A recent CIGRE document published in ELECTRA has described the potential benefits of a direct connection of generators to HVdc converters. While many theoretical contributions have been made, no practical test data has become available so far. This paper reports on harmonic tests carried out at the Benmore end of the New Zealand HVdc link operating as a group connected scheme. It was found that the measured harmonic current levels were well below specified generator ratings. Dynamic simulation accurately predicted the harmonic currents whereas the results of a steady state formulation were less reliable.

  8. Influence of adhesive shear deformation on laminate structural behavior with application to parabolic trough solar collectors. [SHEAR

    SciTech Connect (OSTI)

    Clauss, D.B.; Reuter, R.C. Jr.

    1983-02-01T23:59:59.000Z

    A simplified theory for the bending behavior of a thin flat bi-lamina panel is developed which includes the effects of shear deformation in the central adhesive layer. Static equilibrium equations for elastic thermomechanical cylindrical bending of a thin plate are used. A solution form is proposed which greatly facilitates application of this theory to structural panels with numerous discrete property changes in the variable direction. The influence of adhesive shear stiffness parameters upon overall laminate behavior is characterized through numerical examples typifying various thermal and mechanical loading conditions.

  9. Effect of Shear on Gelation of Polyacrylamide-Chromium Acetate Gelant in a Circular Tube

    E-Print Network [OSTI]

    Li, Xianping

    2010-11-26T23:59:59.000Z

    This research studies the gelation and flow properties of a partially hydrolyzed polyacrylamide (HPAM)-chromium acetate gel system under shear conditions. Gelation was observed in steady shear on a rheometer and during injection through a 1,031-ft...

  10. Analytical Modeling of Wood Frame Shear Walls Subjected to Vertical Load

    E-Print Network [OSTI]

    Nguyendinh, Hai

    2011-08-08T23:59:59.000Z

    referred to as Analytical Model of wood frame SHEar walls subjected to Vertical load (AMSHEV) is based on the kinematic behavior of wood frame shear walls and captures significant characteristics observed from experimental testing through appropriate...

  11. Silicon micromachined sensors and sensor arrays for shear-stress measurements in aerodynamic flows

    E-Print Network [OSTI]

    Padmanabhan, Aravind

    In this thesis we report on a new micromachined floating-element shear-stress sensor for turbulent boundary layer research. Applications in low shear-stress environments such as turbulent boundary layers require extremely ...

  12. Damage to HDPE geomembrane from interface shear over gravelly compacted clay liner

    E-Print Network [OSTI]

    Thielmann, Stuart

    2012-01-01T23:59:59.000Z

    R. S. (2011). “Geomembrane damage due to static and cyclic66 Figure 4.10. GM damage results after shearing for Testsshear displacement on shear strength and GM damage for test

  13. Investigation of shear banding in three-dimensional foams G. Ovarlez1

    E-Print Network [OSTI]

    stress, this leads to the viscosity bifurcation phenomenon [8,9]. This implies that, in addition) and shear-induced resuspension [11]. Some yield stress fluids seem not to exhibit shear banding, although

  14. Shear Stress in Smooth Rectangular Open-Channel Flows and Pierre Y. Julien2

    E-Print Network [OSTI]

    Julien, Pierre Y.

    of three components: (1) gravitational; (2) secondary flows; and (3) interfacial shear stress the logarithmic law to a parabolic cross-sectional open channel and proposed a method to determine the shear

  15. CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR

    E-Print Network [OSTI]

    CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR James R. Rice* ABSTRACT An exact linear elastic-perfectly plastic solution is presented for the problem of a sharp notch coordinates corresponding to given stresses, position of the elastic-plastic boundary, and accompanying

  16. Laboratory Studies on the Effects of Shear on Fish

    SciTech Connect (OSTI)

    Neitzel, Duane A.; Richmond, Marshall C.; Dauble, Dennis D.; Mueller, Robert P.; Moursund, Russell A.; Abernethy, Cary S.; Guensch, Greg R.

    2000-09-20T23:59:59.000Z

    The overall objective of our studies was to specify an index describing the hydraulic force that fish experience when subjected to a shear environment. Fluid shear is a phenomenon that is important to fish. However, elevated levels of shear may result in strain rates that injure or kill fish. At hydroelectric generating facilities, concerns have been expressed that strain rates associated with passage through turbines, spillways, and fish bypass systems may adversely affect migrating fish. Development of fish friendly hydroelectric turbines requires knowledge of the physical forces (injury mechanisms) that impact entrained fish and the fish's tolerance to these forces. It requires up-front, pre-design specifications for the environmental conditions that occur within the turbine system, in other words, determining or assuming that those conditions known to injure fish will provide the descriptions of conditions that engineers must consider in the design of a turbine system. These biological specifications must be carefully and thoroughly documented throughout the design of a fish friendly turbine. To address the development of biological specifications, we designed and built a test facility where juvenile fish could be subjected to a range of shear environments and quantified their biological response.

  17. THE SDSS CO-ADD: COSMIC SHEAR MEASUREMENT

    SciTech Connect (OSTI)

    Lin Huan; Dodelson, Scott; Soares-Santos, Marcelle; Annis, James; Hao Jiangang; Johnston, David; Kubo, Jeffrey M.; Reis, Ribamar R. R. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Seo, Hee-Jong [Berkeley Center for Cosmological Physics, LBL and Department of Physics, University of California, Berkeley, CA 94720 (United States); Simet, Melanie [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2012-12-10T23:59:59.000Z

    Stripe 82 in the Sloan Digital Sky Survey was observed multiple times, allowing deeper images to be constructed by co-adding the data. Here, we analyze the ellipticities of background galaxies in this 275 deg{sup 2} region, searching for evidence of distortions due to cosmic shear. We do so using measurements of both the shear-shear correlation function and power spectrum, with the latter determined using both ''quadratic'' and ''pseudo'' estimation techniques. We show how we verified these methods using mock catalogs. We also describe our methods for modeling and correcting for the effects of the point-spread function (PSF) in our shape measurements, and we also describe our prescription for estimating photometric redshifts (photo-z's) for our galaxy sample. In particular, we assess the impact of potential systematic effects due to the PSF and to photo-z's, and show that these are under control in our analysis. We find consistent correlation function and power spectrum results, where the E-mode cosmic shear signal is detected in both real and Fourier space with >5{sigma} significance on degree scales, while the B-mode is consistent with zero as expected. The amplitude of the signal constrains the combination of the matter density {Omega}{sub m} and fluctuation amplitude {sigma}{sub 8} to be {Omega}{sup 0.7}{sub m}{sigma}{sub 8} = 0.252{sup +0.032}{sub -{sub 0.052}}.

  18. Micromachined Nickel Floating Element Shear Stress Sensor Array , J. Gallmanb

    E-Print Network [OSTI]

    White, Robert D.

    Micromachined Nickel Floating Element Shear Stress Sensor Array Z. Zhaoa , J. Gallmanb , R. Whitea (Technic Copper FB) and patterned lithographically. A Nickel structural layer with varied thickness is deposited from a nickel sulfamate plating solution (Technic Nickel Sulfamate SemiBright) and patterned

  19. Efficiency of Mixing Forced by Unsteady Shear Flow RYUICHIRO INOUE

    E-Print Network [OSTI]

    Smyth, William David

    Efficiency of Mixing Forced by Unsteady Shear Flow RYUICHIRO INOUE Department of Physics form 18 December 2008) ABSTRACT The dependence of mixing efficiency on time-varying forcing is studied frame and allowing the tilt angle to vary in time. Mixing efficiency Gc is defined as the ratio

  20. Shear viscosity of the $\\Phi^4$ theory from classical simulation

    E-Print Network [OSTI]

    Homor, M M

    2015-01-01T23:59:59.000Z

    Shear viscosity of the classical $\\Phi^4$ theory is measured using classical microcanonical simulation. To calculate the Kubo formula, we measure the energy-momentum tensor correlation function, and apply the Green-Kubo relation. Being a classical theory, the results depend on the cutoff which should be chosen in the range of the temperature. Comparison with experimentally accessible systems is also performed.

  1. Shear viscosity of boost invariant plasma at finite coupling

    E-Print Network [OSTI]

    Alex Buchel

    2008-03-04T23:59:59.000Z

    We discuss string theory alpha' corrections in the dual description of the expanding boost invariant N=4 supersymmetric Yang-Mills plasma at strong coupling. We compute finite 't Hooft coupling corrections to the shear viscosity and find that it disagrees with the equilibrium correlation function computations. We comment on the possible source of the discrepancy.

  2. Shear Viscosity to Entropy within a Parton Cascade

    E-Print Network [OSTI]

    A. El; C. Greiner; Z. Xu

    2007-06-28T23:59:59.000Z

    The shear viscosity is calculated by means of the perturbative kinetic partonic cascade BAMPS with CGC initial conditons for various saturation momentum scale Q_s. eta/s ~ 0.15 stays approximately constant when going from RHIC to LHC.

  3. Shear viscosity of the $?^4$ theory from classical simulation

    E-Print Network [OSTI]

    M. M. Homor; A. Jakovac

    2015-05-05T23:59:59.000Z

    Shear viscosity of the classical $\\Phi^4$ theory is measured using classical microcanonical simulation. To calculate the Kubo formula, we measure the energy-momentum tensor correlation function, and apply the Green-Kubo relation. Being a classical theory, the results depend on the cutoff which should be chosen in the range of the temperature. Comparison with experimentally accessible systems is also performed.

  4. Strategic Control of Transverse Jet Shear Layer Instabilities J. Davitian,

    E-Print Network [OSTI]

    M'Closkey, Robert T.

    jet in crossflow or transverse jet. Jet nozzles that are flush as well as elevated with respect indicate that the jet's shear layer transitions to global instability when the jet-to-crossflow velocity THE transverse jet or jet in crossflow (JICF) is a flowfield with widespread applications in energy

  5. Multi-scale investigation of sheared flows in magnetized plasmas

    SciTech Connect (OSTI)

    Thomas, Jr., Dr. Edward

    2014-09-19T23:59:59.000Z

    Flows parallel and perpendicular to magnetic fields in a plasma are important phenomena in many areas of plasma science research. The presence of these spatially inhomogeneous flows is often associated with the stability of the plasma. In fusion plasmas, these sheared flows can be stabilizing while in space plasmas, these sheared flows can be destabilizing. Because of this, there is broad interest in understanding the coupling between plasma stability and plasma flows. This research project has engaged in a study of the plasma response to spatially inhomogeneous plasma flows using three different experimental devices: the Auburn Linear Experiment for Instability Studies (ALEXIS) and the Compact Toroidal Hybrid (CTH) stellarator devices at Auburn University, and the Space Plasma Simulation Chamber (SPSC) at the Naval Research Laboratory. This work has shown that there is a commonality of the plasma response to sheared flows across a wide range of plasma parameters and magnetic field geometries. The goal of this multi-device, multi-scale project is to understand how sheared flows established by the same underlying physical mechanisms lead to different plasma responses in fusion, laboratory, and space plasmas.

  6. Shear-induced sedimentation in yield stress fluids Guillaume Ovarlez

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    if a given material will remain ho- mogeneous during a flow. Using MRI techniques, we study the time the local shear rate in the interstitial fluid. Keywords: Sedimentation; Yield stress fluid; Suspension; MRI some lift or dispersion forces to the particles. This principle is typically used in fluidization

  7. TEC as electric generator in an automobile catalytic converter

    SciTech Connect (OSTI)

    Svensson, R. [Chalmers Univ. of Technology, Goeteborg (Sweden); Holmlid, L. [Univ. of Goeteborg (Sweden). Dept. of Physical Chemistry

    1996-12-31T23:59:59.000Z

    Modern cars use more and more electric power due to more on-board electric systems, e.g., ABS brakes, active suspension systems, electric windows, chair adjustment systems and electronic engine control systems. One possible energy source for electricity generation is to use the waste heat from the car`s engine, which generally is as much as 80% of the total energy from the combustion of the gasoline. Maybe the best location to tap the excess heat is the Catalytic Converter (Cat) in the exhaust system or perhaps at the exhaust pipes close to the engine. The Cat must be kept within a certain temperature interval. Large amounts of heat are dissipated through the wall of the Cat. A Thermionic Energy Converter (TEC) in coaxial form could conveniently be located around the ceramic cartridge of the Cat. Since the TEC is a rather good heat insulator before it reaches its working temperature the Cat will reach working temperature faster, and the final temperature of it can be controlled better when encapsulated in a concentric TEC arrangement. It is also possible to regulate the temperature of the Cat and the TEC by controlling the electrical load of the TEC. The possible working temperatures of present and future Cats appear very suitable for the new low work function collector TEC, which has been demonstrated to work down to 470 K.

  8. Analysis of emitter material transport in thermionic converter

    SciTech Connect (OSTI)

    Paramonov, D.V.; El-Genk, M.S. [Institute for Space and Nuclear Power Studies, Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    1996-03-01T23:59:59.000Z

    Output power and efficiency of a thermionic converter depend on temperatures, cesiated work functions, and emissivities of electrodes as well as the interelectrode gap size. Operation lifetime of a thermionic converter is directly related to the values as well as the stability of these parameters, which can be seriously altered by the transport of emitter material to the collector during operation. Loss rate of tungsten, a preferred emitter material, by sublimation at typical operating temperatures is small (about 3{times}10{sup 7} atom/cm{sup 2}sec at 2000 K). The loss rate, however, can be several orders of magnitude higher in the presence of gaseous contaminants. Accelerated transport of emitter material to collector surface changes the effective emissivity and work functions of the electrodes, resulting in performance degradation. A phenomenological model was developed to simulate emitter material transport to the collector in the presence of oxygen, water vapor, and carbon oxide contaminants. The model accounts for interaction of these contaminants with both emitter and collector. Model results were in agreement with experimental data and theoretical results of other investigators. An analysis was performed to determine steady-state chemical composition of deposited material onto the collector surface in the presence of H{sub 2}O, O{sub 2}, and H{sub 2} gaseous contaminants. {copyright} {ital 1996 American Institute of Physics.}

  9. Thermionic converters for an Integrated Solar Upper Stage (ISUS)

    SciTech Connect (OSTI)

    Anderson, W.G.; Horner-Richardson, K. [Thermacore, Inc., Lancaster, PA (United States)

    1996-12-31T23:59:59.000Z

    The Integrated Solar Upper Stage (ISUS) is a solar bimodal system which combines thermal propulsion and electric power generation in a single integrated system. A thermionic converter was designed and fabricated for the ISUS system. The ISUS thermionic energy converters differ from previous designs, due to the significant changes in operating temperature prior to and during an eclipse, with the emitter temperature increasing from 1,900 K to 2,200 K, and then back again. A complete thermal and electrical model was developed for a planar diode to determine optimum operating dimensions and parameters. The model includes an overall energy balance for the diode, and changes the interelectrode gap spacing due to thermal expansion of the parts as the emitter and/or collector temperatures change. Cesium pressure can be chosen from an external liquid reservoir, an integral reservoir using cesium intercalated into graphite attached to the collector heat pipe, or optimum cesium pressure. With optimum cesium pressure, the maximum efficiency increases from 14% to 16% as the emitter temperature increases from 1,900 K to 2,200 K. The improvement in efficiency is only 2% as the emitter temperature is increased. Optimum efficiency requires an external, actively controlled liquid reservoir.

  10. Triple voltage dc-to-dc converter and method

    DOE Patents [OSTI]

    Su, Gui-Jia (Knoxville, TN)

    2008-08-05T23:59:59.000Z

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  11. Converting Maturing Nuclear Sites to Integrated Power Production Islands

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

    Solbrig, Charles W.

    2011-01-01T23:59:59.000Z

    Nuclear islands, which are integrated power production sites, could effectively sequester and safeguard the US stockpile of plutonium. A nuclear island, an evolution of the integral fast reactor, utilizes all the Transuranics (Pu plus minor actinides) produced in power production, and it eliminates all spent fuel shipments to and from the site. This latter attribute requires that fuel reprocessing occur on each site and that fast reactors be built on-site to utilize the TRU. All commercial spent fuel shipments could be eliminated by converting all LWR nuclear power sites to nuclear islands. Existing LWR sites have the added advantage ofmore »already possessing a license to produce nuclear power. Each could contribute to an increase in the nuclear power production by adding one or more fast reactors. Both the TRU and the depleted uranium obtained in reprocessing would be used on-site for fast fuel manufacture. Only fission products would be shipped to a repository for storage. The nuclear island concept could be used to alleviate the strain of LWR plant sites currently approaching or exceeding their spent fuel pool storage capacity. Fast reactor breeding ratio could be designed to convert existing sites to all fast reactors, or keep the majority thermal.« less

  12. EMISSIONS REDUCTIONS USING HYDROGEN FROM PLASMATRON FUEL CONVERTERS

    SciTech Connect (OSTI)

    Bromberg, L

    2000-08-20T23:59:59.000Z

    Substantial progress in engine emission control is needed in order to meet present and proposed regulations for both spark ignition and diesel engines. Tightening regulations throughout the world reflect the ongoing concern with vehicle emissions. Recently developed compact plasmatron fuel converters have features that are suitable for onboard production of hydrogen for both fuel pretreatment and for exhaust aftertreatment applications. Systems that make use of these devices in conjunction with aftertreatment catalysts have the potential to improve significantly prospects for reduction of diesel engine emissions. Plasmatron fuel converters can provide a rapid response compact means to transform efficiently a wide range of hydrocarbon fuels into hydrogen rich gas. They have been used to reform natural gas [Bromberg1], gasoline [Green], diesel [Bromberg2] and hard-to-reform biofuels [Cohn1] into hydrogen rich gas (H2 + CO). The development of these devices has been pursued for the purpose of reducing engine exhaust pollutants by providing hydrogen rich gas for combustion in spark ignition and possibly diesel engines, as shown in Figure 1 [Cohn2]. Recent developments in compact plasmatron reformer design at MIT have resulted in substantial decreases in electrical power requirements. These new developments also increase the lifetime of the electrodes.

  13. SHEARING BOX SIMULATIONS OF THE MRI IN A COLLISIONLESS PLASMA Prateek Sharma and Gregory W. Hammett

    E-Print Network [OSTI]

    Hammett, Greg

    of the MRI in a collision- less plasma, focusing on local simulations in the shearing box limit. Quataert et

  14. Mechanical properties of jammed packings of frictionless spheres under applied shear stress

    E-Print Network [OSTI]

    Hao Liu; Hua Tong; Ning Xu

    2015-02-03T23:59:59.000Z

    By minimizing a thermodynamic-like potential, we unbiasedly sample the potential energy landscape of soft and frictionless spheres under constant shear stress. We obtain zero-temperature jammed states under desired shear stresses and investigate their mechanical properties as a function of the shear stress. As a comparison, we also obtain jammed states from the quasistatic-shear sampling in which the shear stress is not well-controlled. Although the yield stresses determined by both samplings show the same power-law scaling with the compression from point $J$, i.e.~the jamming transition point at zero temperature and shear stress, for finite size systems, the quasistatic-shear sampling leads to a lower yield stress and a higher critical volume fraction of point $J$. The shear modulus of jammed solids decreases when increasing the shear stress. However, the shear modulus does not decay to zero at yielding. This discontinuous change of the shear modulus implies the discontinuous nature of the unjamming transition under nonzero shear stress, which is further verified by the observation of a discontinuous jump of the pressure from jammed solids to shear flows. The pressure jump decreases upon decompression and approaches zero at the critical-like point $J$, in analogy with well-known phase transitions under external field. The analysis of force networks in jammed solids reveals that the force distribution is more sensitive to the increase of the shear stress near point $J$. The force network anisotropy increases with the shear stress. Weak particle contacts near the average force and under large shear stresses exhibit asymmetric angle distribution.

  15. Wind shear climatology for large wind turbine generators

    SciTech Connect (OSTI)

    Elliott, D.L.; Wendell, L.L.; Heflick, S.K.

    1982-10-01T23:59:59.000Z

    Climatological wind shear analyses relevant to the design and operation of multimegawatt wind turbines are provided. Insight is provided for relating the wind experienced by a rotating blade in a shear flow to the analysis results. A simple analysis of the wind experienced by a rotating blade for three types of wind shear profiles under steady-state conditions is presented in graphical form. Comparisons of the magnitude and frequency of the variations in 1) the wind sensed by a single blade element, 2) the sum, and 3) the difference of the winds sensed by opposite blade elements show strong sensitivity to profile shape. These three items represent forcing functions that can be related to 1) flatwise bending moment, 2) torque on the shaft, and 3) teeter angle. A computer model was constructed to simulate rotational sampling of 10-s sampled winds from a tall tower for three different types of large wind turbines. Time series produced by the model indicated that the forcing functions on a rotating blade vary according to the shear profile encountered during each revolution as opposed to a profile derived from average wind conditions, e.g., hourly average winds. An analysis scheme was developed to establish a climatology of wind shear profiles derived from 10-s sampled winds and hourly average winds measured over a one-year period at several levels on a tall tower. Because of the sensitivity of the forcing function variability to profile shape, the analyses performed and presented are in the form of joint frequency distributions of velocity differences of the the top-to-hub versus the hub-to-bottom portion of disks of rotation for the three turbine configurations.

  16. Shear flow effects on ion thermal transport in tokamaks

    SciTech Connect (OSTI)

    Tajima, T.; Horton, W.; Dong, J.Q. [Univ. of Texas, Austin, TX (United States). Institute for Fusion Studies; Kishimoto, Y. [JAERI (Japan). Naka Fusion Research

    1995-03-01T23:59:59.000Z

    From various laboratory and numerical experiments, there is clear evidence that under certain conditions the presence of sheared flows in a tokamak plasma can significantly reduce the ion thermal transport. In the presence of plasma fluctuations driven by the ion temperature gradient, the flows of energy and momentum parallel and perpendicular to the magnetic field are coupled with each other. This coupling manifests itself as significant off-diagonal coupling coefficients that give rise to new terms for anomalous transport. The authors derive from the gyrokinetic equation a set of velocity moment equations that describe the interaction among plasma turbulent fluctuations, the temperature gradient, the toroidal velocity shear, and the poloidal flow in a tokamak plasma. Four coupled equations for the amplitudes of the state variables radially extended over the transport region by toroidicity induced coupling are derived. The equations show bifurcations from the low confinement mode without sheared flows to high confinement mode with substantially reduced transport due to strong shear flows. Also discussed is the reduced version with three state variables. In the presence of sheared flows, the radially extended coupled toroidal modes driven by the ion temperature gradient disintegrate into smaller, less elongated vortices. Such a transition to smaller spatial correlation lengths changes the transport from Bohm-like to gyrobohm-like. The properties of these equations are analyzed. The conditions for the improved confined regime are obtained as a function of the momentum-energy deposition rates and profiles. The appearance of a transport barrier is a consequence of the present theory.

  17. Reflective Cracking Study: First-level Report on Laboratory Shear Testing

    E-Print Network [OSTI]

    Tsai, Bor-Wen; Jones, David; Harvey, John T; Monismith, Carl L.; Guada, I.; Signore, J,

    2008-01-01T23:59:59.000Z

    2 and ? 2 ln? 3 and ? 3 lnG lnkcy5 lnn 1 lnn 2 lnNf lnpct559 Figure 4.28: Residual plots of LnG. (Pooled ShearResilient Shear Modulus, G* (lng) The Resilient Shear

  18. Geosynthetics International, 2004, 11, No. 3 State-of-the-art report: GCL shear strength and

    E-Print Network [OSTI]

    ­ displacement behavior and shear strength interpretation are presented, including long-term performance issues (GCLs) are needed for static and seismic stability analyses in the design of waste containment of GCLs. Essential concepts of shear stress­displacement behavior and shear strength interpretation

  19. Impact of Wind Shear and Tower Shadow Effects on Power System with Large Scale Wind Power

    E-Print Network [OSTI]

    Hu, Weihao

    Impact of Wind Shear and Tower Shadow Effects on Power System with Large Scale Wind Power to wind speed variations, the wind shear and the tower shadow effects. The fluctuating power may be ableSILENT/PowerFactory. In this paper, the impacts of wind shear and tower shadow effects on the small signal stability of power systems

  20. Spring structure for a thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, Daniel T. (La Jolla, CA)

    1992-01-01T23:59:59.000Z

    A support is provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  1. Spring structure for a thermionic converter emitter support arrangement

    DOE Patents [OSTI]

    Allen, D.T.

    1992-03-17T23:59:59.000Z

    A support is provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs. 7 figs.

  2. Results from the microminiature thermionic converter demonstration testing program

    SciTech Connect (OSTI)

    King, Donald B.; Wyant, Francis J. [International Nuclear Safety Department, Sandia National Laboratories, MS-0744, Albuquerque, New Mexico 87185 (United States)] Luke, James R. [New Mexico Engineering Research Institute, 901 University Blvd. SE, Albuquerque, New Mexico 87106 (United States)

    1999-01-01T23:59:59.000Z

    Research is in progress to develop microminiature thermionic converters (MTCs) with high energy conversion efficiencies and variable operating temperatures using semiconductor integrated circuit (IC) fabrication methods. The use of IC techniques allows the fabrication of MTCs with cathode to anode spacing of several microns or less and with anode and cathode materials that will have work functions ranging from 1 eV to 3 eV. The small cathode to anode spacing and variable electrode work functions should allow the conversion of heat energy to relatively large current densities (up to tens of Amps/cm{sup 2}) at relatively high conversion efficiencies (15{endash}25{percent}). {copyright} {ital 1999 American Institute of Physics.}

  3. Utilizing zero-sequence switchings for reversible converters

    DOE Patents [OSTI]

    Hsu, John S.; Su, Gui-Jia; Adams, Donald J.; Nagashima, James M.; Stancu, Constantin; Carlson, Douglas S.; Smith, Gregory S.

    2004-12-14T23:59:59.000Z

    A method for providing additional dc inputs or outputs (49, 59) from a dc-to-ac inverter (10) for controlling motor loads (60) comprises deriving zero-sequence components (V.sub.ao, V.sub.bo, and V.sub.co) from the inverter (10) through additional circuit branches with power switching devices (23, 44, 46), transforming the voltage between a high voltage and a low voltage using a transformer or motor (42, 50), converting the low voltage between ac and dc using a rectifier (41, 51) or an H-bridge (61), and providing at least one low voltage dc input or output (49, 59). The transformation of the ac voltage may be either single phase or three phase. Where less than a 100% duty cycle is acceptable, a two-phase modulation of the switching signals controlling the inverter (10) reduces switching losses in the inverter (10). A plurality of circuits for carrying out the invention are also disclosed.

  4. The Force of a Tsunami on a Wave Energy Converter

    E-Print Network [OSTI]

    O'Brien, Laura; Renzi, Emiliano; Dutykh, Denys; Dias, Frédéric

    2012-01-01T23:59:59.000Z

    With an increasing emphasis on renewable energy resources, wave power technology is fast becoming a realistic solution. However, the recent tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed creating large destructive waves. The question posed here is whether a nearshore wave energy converter (WEC) could withstand the force of an incoming tsunami. The analytical 3D model of Renzi & Dias (2012) developed within the framework of a linear theory and applied to an array of fixed plates is used. The time derivative of the velocity potential allows the hydrodynamic force to be calculated.

  5. NREL Research on Converting Biomass to Liquid Fuels

    ScienceCinema (OSTI)

    None

    2013-05-29T23:59:59.000Z

    Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called "biofuels," to help meet transportation fuel needs. The two most common types of biofuels are ethanol and biodiesel. Today, ethanol is made from starches and sugars, but at the National Renewable Energy Laboratory (NREL) scientists are developing technology to allow it to be made from cellulose and hemicellulose, the fibrous material that makes up the bulk of most plant matter. Biodiesel is made by combining alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. It can be used as an additive (typically 20%) to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines. For a text version of this video visit http://www.nrel.gov/learning/re_biofuels.html

  6. NREL Research on Converting Biomass to Liquid Fuels

    SciTech Connect (OSTI)

    None

    2010-01-01T23:59:59.000Z

    Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called "biofuels," to help meet transportation fuel needs. The two most common types of biofuels are ethanol and biodiesel. Today, ethanol is made from starches and sugars, but at the National Renewable Energy Laboratory (NREL) scientists are developing technology to allow it to be made from cellulose and hemicellulose, the fibrous material that makes up the bulk of most plant matter. Biodiesel is made by combining alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. It can be used as an additive (typically 20%) to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines. For a text version of this video visit http://www.nrel.gov/learning/re_biofuels.html

  7. A Study of Radiative Bottomonium Transitions using Converted Photons

    SciTech Connect (OSTI)

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; /INFN, Bari /Bari U.; Milanes, D.A.; /INFN, Bari; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /UC, Berkeley; Koch, H.; Schroeder, T.; /Ruhr U., Bochum; Asgeirsson, D.J.; Hearty, C.; /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Paris U., VI-VII /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2011-08-15T23:59:59.000Z

    The authors use (111 {+-} 1) million {Upsilon}(3S) and (89 {+-} 1) million {Upsilon}(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions betwen bottomonium states using photons that have been converted to e{sup +}e{sup -} pairs by the detector material. They observe {Upsilon}(3S) {yields} {gamma}{chi}{sub b0,2}(1P) decay, make precise measurements of the branching fractions for {chi}{sub b1,2}(1P, 2P) {yields} {gamma}{Upsilon}(1S) and {chi}{sub b1,2}(2P) {yields} {gamma}{Upsilon}(2S) decays, and search for radiative decay to the {eta}{sub b}(1S) and {eta}{sub b}(2S) states.

  8. Apparatuses and method for converting electromagnetic radiation to direct current

    DOE Patents [OSTI]

    Kotter, Dale K; Novack, Steven D

    2014-09-30T23:59:59.000Z

    An energy conversion device may include a first antenna and a second antenna configured to generate an AC current responsive to incident radiation, at least one stripline, and a rectifier coupled with the at least one stripline along a length of the at least one stripline. An energy conversion device may also include an array of nanoantennas configured to generate an AC current in response to receiving incident radiation. Each nanoantenna of the array includes a pair of resonant elements, and a shared rectifier operably coupled to the pair of resonant elements, the shared rectifier configured to convert the AC current to a DC current. The energy conversion device may further include a bus structure operably coupled with the array of nanoantennas and configured to receive the DC current from the array of nanoantennas and transmit the DC current away from the array of nanoantennas.

  9. MAGNETIC FIELD GENERATION AND PARTICLE ENERGIZATION AT RELATIVISTIC SHEAR BOUNDARIES IN COLLISIONLESS ELECTRON-POSITRON PLASMAS

    SciTech Connect (OSTI)

    Liang, Edison; Smith, Ian [Rice University, MS 108, 6100 Main Street, Houston, TX 77005 (United States); Boettcher, Markus, E-mail: liang@rice.edu, E-mail: iansmith@rice.edu, E-mail: boettchm@ohio.edu [Physics and Astronomy Department, Ohio University, Athens, OH 45701 (United States)

    2013-04-01T23:59:59.000Z

    Using particle-in-cell simulations, we study the kinetic physics of relativistic shear flow in collisionless electron-positron (e+e-) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary, driven by streaming instabilities across the shear interface and sustained by the shear flow. Nonthermal, anisotropic high-energy particles are accelerated across field lines to produce a power-law tail turning over just below the shear Lorentz factor. These results have important implications for the dissipation and radiation of jets in blazars and gamma-ray bursts.

  10. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    SciTech Connect (OSTI)

    Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.

    2015-01-01T23:59:59.000Z

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  11. Reference Model 6 (RM6): Oscillating Wave Energy Converter.

    SciTech Connect (OSTI)

    Bull, Diana L; Smith, Chris; Jenne, Dale Scott; Jacob, Paul; Copping, Andrea; Willits, Steve; Fontaine, Arnold; Brefort, Dorian; Gordon, Margaret Ellen; Copeland, Robert; Jepsen, Richard A.

    2014-10-01T23:59:59.000Z

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter reference model design in a complementary manner to Reference Models 1-4 contained in the above report. In this report, a conceptual design for an Oscillating Water Column Wave Energy Converter (WEC) device appropriate for the modeled reference resource site was identified, and a detailed backward bent duct buoy (BBDB) device design was developed using a combination of numerical modeling tools and scaled physical models. Our team used the methodology in SAND2013-9040 for the economic analysis that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays, up to 100 devices. The methodology was applied to identify key cost drivers and to estimate levelized cost of energy (LCOE) for this RM6 Oscillating Water Column device in dollars per kilowatt-hour (%24/kWh). Although many costs were difficult to estimate at this time due to the lack of operational experience, the main contribution of this work was to disseminate a detailed set of methodologies and models that allow for an initial cost analysis of this emerging technology. This project is sponsored by the U.S. Department of Energy's (DOE) Wind and Water Power Technologies Program Office (WWPTO), within the Office of Energy Efficiency & Renewable Energy (EERE). Sandia National Laboratories, the lead in this effort, collaborated with partners from National Laboratories, industry, and universities to design and test this reference model.

  12. COMPARISON OF SHEAR STRENGTH OF CERAMIC JOINTS DETERMINED BY VARIOUS TEST METHODS WITH SMALL SPECIMENS

    SciTech Connect (OSTI)

    Shih, Chunghao Phillip [ORNL; Katoh, Yutai [ORNL; Kiggans Jr, James O [ORNL; Koyanagi, Takaaki [ORNL; Khalifa, Hesham [General Atomics, San Diego; Back, Christina A. [General Atomics, San Diego; Hinoki, Tatsuya [Kyoto University, Japan; Ferraris, Monica [Politecnico di Torino

    2015-01-01T23:59:59.000Z

    Four different shear test methods i.e. doubled notched shear test, asymmetrical four point bend test, Iosipescu test, and torsion test, were investigated for their ability to evaluate one standard SiC to SiC ceramic brittle joint while using small size specimens. Double notched shear test showed higher stress concentration at the notch base and a lower nominal shear strength. Both asymmetrical four point bend test and Iosipescu test utilized epoxy jointed metal extensors, which failed during test and caused misalignment and tensile type of failure. Torsion test can deliver true shear loading. However, base material failure was observed for the torsion joint samples in this study. None of the tests can successfully induce true shear failure of the joint because the joint is stronger and tougher than the SiC substrate. Torsion test appears to be promising because of the pure shear loading, less stress concentration, and easy alignment.

  13. Solar energy power generators with advanced thermionic converters for spacecraft applications

    SciTech Connect (OSTI)

    Sahin, S.

    1981-01-01T23:59:59.000Z

    This study presents (1) a 50 kW/sub e/ solar energy generator in a geostationary orbit for direct tv-broadcasting and (2) a 10 GW/sub e/ space power plant, with the basic engineering outlines using an advanced thermionic converter proposal given for each. Further, a comparison of the main technical data for the generators with corresponding energy output using (1) advanced thermionic converter and (2) ordinary thermionic converter without auxiliary emitter is shown. 25 refs.

  14. Soft-Switching High-Frequency AC-Link Universal Power Converters with Galvanic Isolation

    E-Print Network [OSTI]

    Amirabadi, Mahshid

    2013-08-07T23:59:59.000Z

    ) direct drive using wound-field synchronous generator [10]. ...................................................................................................... 6 Figure 6 Dc-dc buck-boost converter: (a) configuration, (b) energizing mode (mode 1), (c...) de-energizing mode (mode 2), (d) voltage and current waveforms ........ 12 Figure 7 An alternative representation of the dc-dc buck-boost converter ...................... 13 Figure 8 Dc-dc ac-link buck-boost converter: configuration, behavior...

  15. An Integrated Onboard Charger and Accessary Power Converter for Plug-in Electric Vehicles

    SciTech Connect (OSTI)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

    2013-01-01T23:59:59.000Z

    Abstract: In this paper, an integrated onboard battery charger and accessary dc-dc converter for plug-in electric vehicles (PEVs) is presented. The idea is to utilize the already available traction drive inverters and motors of a PEV as the frond converter of the charger circuit and the transformer of the 14 V accessary dc-dc converter to provide galvanic isolation. The topology was verified by modeling and experimental results on a 5 kW charger prototype

  16. Feedback Control of Turbulent Shear Flows by Genetic Programming

    E-Print Network [OSTI]

    Duriez, Thomas; von Krbek, Kai; Bonnet, Jean-Paul; Cordier, Laurent; Noack, Bernd R; Segond, Marc; Abel, Markus; Gautier, Nicolas; Aider, Jean-Luc; Raibaudo, Cedric; Cuvier, Christophe; Stanislas, Michel; Debien, Antoine; Mazellier, Nicolas; Kourta, Azeddine; Brunton, Steven L

    2015-01-01T23:59:59.000Z

    Turbulent shear flows have triggered fundamental research in nonlinear dynamics, like transition scenarios, pattern formation and dynamical modeling. In particular, the control of nonlinear dynamics is subject of research since decades. In this publication, actuated turbulent shear flows serve as test-bed for a nonlinear feedback control strategy which can optimize an arbitrary cost function in an automatic self-learning manner. This is facilitated by genetic programming providing an analytically treatable control law. Unlike control based on PID laws or neural networks, no structure of the control law needs to be specified in advance. The strategy is first applied to low-dimensional dynamical systems featuring aspects of turbulence and for which linear control methods fail. This includes stabilizing an unstable fixed point of a nonlinearly coupled oscillator model and maximizing mixing, i.e.\\ the Lyapunov exponent, for forced Lorenz equations. For the first time, we demonstrate the applicability of genetic p...

  17. SHEAR STRENGTH MEASURING EQUIPMENT EVALUATION AT THE COLD TEST FACILITY

    SciTech Connect (OSTI)

    MEACHAM JE

    2009-09-09T23:59:59.000Z

    Retrievals under current criteria require that approximately 2,000,000 gallons of double-shell tank (DST) waste storage space not be used to prevent creating new tanks that might be susceptible to buoyant displacement gas release events (BDGRE). New criteria are being evaluated, based on actual sludge properties, to potentially show that sludge wastes do not exhibit the same BDGRE risk. Implementation of the new criteria requires measurement of in situ waste shear strength. Cone penetrometers were judged the best equipment for measuring in situ shear strength and an A.P. van den berg Hyson 100 kN Light Weight Cone Penetrometer (CPT) was selected for evaluation. The CPT was procured and then evaluated at the Hanford Site Cold Test Facility. Evaluation demonstrated that the equipment with minor modification was suitable for use in Tank Farms.

  18. Triaxial determination of shear strength of tire chips

    SciTech Connect (OSTI)

    Wu, W.Y.; Benda, C.C.; Cauley, R.F. [Vermont Agency of Transportation, Montpelier, VT (United States)

    1997-05-01T23:59:59.000Z

    Triaxial compression tests following stress paths of constant {sigma}{sub 1} were conducted to determine the shear strength of five processed scrap tire products having different gradations and particle shapes. The interparticle frictional component was separated from the total shear strength according to the energy correction concept proposed by researchers. The experimental results show that all five tire chip products have ultimate internal friction angles of 45{degree} to over 60{degree}. The interparticle frictional component of the strength was fully mobilized and nearly reached a constant value after approximately 5% axial strain. The experimental results confirmed that the strength parameter obtained with constant {sigma}{sub 1} was more reasonable. This finding is supported by field observation in which the tire chips have an angle of repose ranging from 37{degree} to 43{degree} (loosely stock piled) and up to 85{degree} (compacted). The engineering applications of the experimental results are discussed.

  19. The effect of dynamic simple shear on marine sediment

    E-Print Network [OSTI]

    Carpenter, Samuel Harley

    1972-01-01T23:59:59.000Z

    rates available cover nearly three orders of magnitude from 0. 2 RAD/SEC to 80 RAD/SEC. While these shear rates are considered extremely high for soil me- chanics work they are extremely low in comparison with velocities achieved during... of depth. The top layer was not tested in the vane shear device. The data groups around a straight 1. 3 1. 2 g 80. 0 RAD/SEC 20. 0 RAD/SEC 2. 0 RAD/SEC 0 8 y 0. 2 RAD/SEC 0 -0. 2 RAD/SEC 43 -2. 0 RAD/SEC 64, -20. 0 RAD/SEC -80. 0 RAD/SEC 10 20 30...

  20. Toroidal momentum transport in a tokamak due to profile shearing

    SciTech Connect (OSTI)

    Buchholz, R.; Grosshauser, S. R.; Hornsby, W. A.; Migliano, P.; Peeters, A. G. [Physics Department, University of Bayreuth, Universitätsstrasse 30 Bayreuth (Germany); Camenen, Y. [Aix-Marseille Université, CNRS, PIIM UMR 7345, Marseille 13397 (France); Casson, F. J. [EURATOM Association, Max Planck Institut fuer Plasmaphysik, Boltzmannstrasse 2, Garching 85748 (Germany)

    2014-06-15T23:59:59.000Z

    The effect of profile shearing on toroidal momentum transport is studied in linear and non-linear gyro-kinetic simulations. Retaining the radial dependence of both plasma and geometry parameters leads to a momentum flux that has contributions both linear in the logarithmic gradients of density and temperature, as well as contributions linear in the derivatives of the logarithmic gradients. The effect of the turbulence intensity gradient on momentum transport is found to be small for the studied parameters. Linear simulations at fixed normalized toroidal wave number predict a weak dependence of the momentum flux on the normalized Larmor radius ?{sub *}=?/R. Non-linear simulations, however, at sufficiently small ?{sub *} show a linear scaling of the momentum flux with ?{sub *}. The obtained stationary rotation gradients are in the range of, although perhaps smaller than, current experiments. For a reactor plasma, however, a rather small rotation gradient should result from profile shearing.

  1. Absolute Measurement Of Laminar Shear Rate Using Photon Correlation Spectroscopy

    E-Print Network [OSTI]

    Elliot Jenner; Brian D'Urso

    2015-05-11T23:59:59.000Z

    An absolute measurement of the components of the shear rate tensor $\\mathcal{S}$ in a fluid can be found by measuring the photon correlation function of light scattered from particles in the fluid. Previous methods of measuring $\\mathcal{S}$ involve reading the velocity at various points and extrapolating the shear, which can be time consuming and is limited in its ability to examine small spatial scale or short time events. Previous work in Photon Correlation Spectroscopy has involved only approximate solutions, requiring free parameters to be scaled by a known case, or different cases, such as 2-D flows, but here we present a treatment that provides quantitative results directly and without calibration for full 3-D flow. We demonstrate this treatment experimentally with a cone and plate rheometer.

  2. Plasticity of a colloidal polycrystal under cyclic shear

    E-Print Network [OSTI]

    Elisa Tamborini; Luca Cipelletti; Laurence Ramos

    2014-08-27T23:59:59.000Z

    We use confocal microscopy and time-resolved light scattering to investigate plasticity in a col- loidal polycrystal, following the evolution of the network of grain boundaries as the sample is submitted to thousands of shear deformation cycles. The grain boundary motion is found to be ballistic, with a velocity distribution function exhibiting non-trivial power law tails. The shear- induced dynamics initially slow down, similarly to the aging of the spontaneous dynamics in glassy materials, but eventually reach a steady state. Surprisingly, the cross-over time between the ini- tial aging regime and the steady state decreases with increasing probed length scale, hinting at a hierarchical organization of the grain boundary dynamics.

  3. No-hair conjectures, primordial shear and protoinflationary initial conditions

    E-Print Network [OSTI]

    Massimo Giovannini

    2013-12-17T23:59:59.000Z

    Anisotropic inflationary background geometries are analyzed in the context of an extended gauge action where the electric and magnetic susceptibilities are not bound to coincide and depend on the inflaton field. After deriving various classes of solutions with electric and magnetic hairs, we discuss the problem of the initial boundary conditions of the shear parameter and consider a globally neutral plasma as a possible relic of a preinflationary stage of expansion. While electric hairs are washed out by the finite value of the protoinflationary conductivity, magnetic hairs can persist and introduce a tiny amount of shear causing a different inflationary rate of expansion along orthogonal spatial directions. The plasma interactions are a necessary criterion to discriminate between physical and unphysical initial conditions but they are not strictly sufficient to warrant the stability of a given magnetic solution.

  4. Finite element analyses for seismic shear wall international standard problem

    SciTech Connect (OSTI)

    Park, Y.J.; Hofmayer, C.H.

    1998-04-01T23:59:59.000Z

    Two identical reinforced concrete (RC) shear walls, which consist of web, flanges and massive top and bottom slabs, were tested up to ultimate failure under earthquake motions at the Nuclear Power Engineering Corporation`s (NUPEC) Tadotsu Engineering Laboratory, Japan. NUPEC provided the dynamic test results to the OECD (Organization for Economic Cooperation and Development), Nuclear Energy Agency (NEA) for use as an International Standard Problem (ISP). The shear walls were intended to be part of a typical reactor building. One of the major objectives of the Seismic Shear Wall ISP (SSWISP) was to evaluate various seismic analysis methods for concrete structures used for design and seismic margin assessment. It also offered a unique opportunity to assess the state-of-the-art in nonlinear dynamic analysis of reinforced concrete shear wall structures under severe earthquake loadings. As a participant of the SSWISP workshops, Brookhaven National Laboratory (BNL) performed finite element analyses under the sponsorship of the U.S. Nuclear Regulatory Commission (USNRC). Three types of analysis were performed, i.e., monotonic static (push-over), cyclic static and dynamic analyses. Additional monotonic static analyses were performed by two consultants, F. Vecchio of the University of Toronto (UT) and F. Filippou of the University of California at Berkeley (UCB). The analysis results by BNL and the consultants were presented during the second workshop in Yokohama, Japan in 1996. A total of 55 analyses were presented during the workshop by 30 participants from 11 different countries. The major findings on the presented analysis methods, as well as engineering insights regarding the applicability and reliability of the FEM codes are described in detail in this report. 16 refs., 60 figs., 16 tabs.

  5. Location of the solar dynamo and near-surface shear

    E-Print Network [OSTI]

    Axel Brandenburg

    2005-12-29T23:59:59.000Z

    The location of the solar dynamo is discussed in the context of new insights into the theory of nonlinear turbulent dynamos. It is argued that, from a dynamo-theoretic point of view, the bottom of the convection zone is not a likely location and that the solar dynamo may be distributed over the convection zone. The near surface shear layer produces not only east-west field alignment, but it also helps the dynamo disposing of its excess small scale magnetic helicity.

  6. Theory of semicollisional kinetic Alfven modes in sheared magnetic fields

    SciTech Connect (OSTI)

    Hahm, T.S.; Chen, L.

    1985-02-01T23:59:59.000Z

    The spectra of the semicollisional kinetic Alfven modes in a sheared slab geometry are investigated, including the effects of finite ion Larmor radius and diamagnetic drift frequencies. The eigenfrequencies of the damped modes are derived analytically via asymptotic analyses. In particular, as one reduces the resistivity, we find that, due to finite ion Larmor radius effects, the damped mode frequencies asymptotically approach finite real values corresponding to the end points of the kinetic Alfven continuum.

  7. Evolution of shear-induced melting in dusty plasma

    E-Print Network [OSTI]

    Yan Feng; J. Goree; Bin Liu

    2010-04-05T23:59:59.000Z

    The spatiotemporal development of melting is studied experimentally in a 2D dusty plasma suspension. Starting with an ordered lattice, and then suddenly applying localized shear, a pair of counter-propagating flow regions develop. A transition between two melting stages is observed before a steady state is reached. Melting spreads with a front that propagates at the transverse sound speed. Unexpectedly, coherent longitudinal waves are excited in the flow region.

  8. Repetitive and Iterative Learning Control for Power Converter and Precision Motion Control

    E-Print Network [OSTI]

    Teng, Kuo-Tai

    2014-01-01T23:59:59.000Z

    3 Repetitive Control of Power Inverter for Harmonic4 Repetitive Control of Power Rectifier for HarmonicThe typical PI controlled power converters can not guarantee

  9. New Family of Multilevel Matrix Converters for Wind Power Applications: Final Report, July 2002 - March 2006

    SciTech Connect (OSTI)

    Erickson, R.; Angkititrakul, S.; Almazeedi, K.

    2006-12-01T23:59:59.000Z

    The goal of this project was to develop a new modular multilevel matrix converter for wind power applications and to demonstrate a working scale model in the laboratory.

  10. Coal-fired furnace for testing of thermionic converters. Topical report

    SciTech Connect (OSTI)

    Not Available

    1980-10-01T23:59:59.000Z

    The development of thermionic converter technology has progressed to make near-term applications interesting. One of these applications is the thermionic topping of a pulverized coal-fired central station powerplant. Up to now, thermionic converters have been flame tested using natural gas as fuel. A new test furnace is required for evaluation of thermionic converters in a coal-fired environment. The design and costs of a facility which adapts a coal-fired furnace built by Foster Wheeler Development Corporation (FWDC) for thermionic converter testing are discussed. Such a facility would be exempt from air pollution regulations because of its low firing rate.

  11. angiotensin-converting enzyme levels: Topics by E-print Network

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

    enzyme activity is significantly determined by a gene polymorphism. Homozygous Brown Norway rats have higher plasma angiotensin I-converting enzyme (more) Jalil Milad, Jorge...

  12. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Song Chi; Ahmed Elasser; Maja Harfman-Todorovic; Yan Jiang; Frank Mueller; Fengfeng Tao

    2012-06-01T23:59:59.000Z

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  13. ac-dc back-to-back converter: Topics by E-print Network

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

    and simulation of the interconnection of a back-to-back converter modulated transformers (MTF in the bond graph language) instead of the pairs of complementary switches...

  14. DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Maja Harfman-Todorovic; Ahmed Elasser; Juan A. Sabate; Robert L. Steigerwald; Yan Jiang; Somasundaram Essakiappan

    2011-07-01T23:59:59.000Z

    Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

  15. Application of direct pulsewidth modulation scheme to AC-DC converters: - a way to reduce ripple

    E-Print Network [OSTI]

    Zhang, Yuemin

    1993-01-01T23:59:59.000Z

    Modulation (ISPWM), 4 Direct Pulsewidth Modulation (DPWM). 15 5 Single Phase Half Controlled PWM ac-dc Converter . 6 Single Phase Full controlled PWM ac-dc Converter . 18 18 7 Simulation of SPWM ac-dc Converter. 20 8 Output Voltage Spectra of SPWM ac... 30 Balanced Three Phase Inputs 31 Output Voltage of A Three Phase Full Controlled ac-dc SPWM Converter. 42 32 Output Voltage of A Three Phase Full Controlled ac-dc EPWM Con- verter 33 Output Voltage of A Three Phase Full Controlled ac-dc ISPWM Con...

  16. Bibliography on overvoltage protection and insulation coordination of HVDC converter stations, 1979-1989

    SciTech Connect (OSTI)

    Not Available

    1991-04-01T23:59:59.000Z

    This bibliography is a listing of references on the subject of overvoltage protection and insulation coordination of HVDC converter stations, for the years 1979 through 1989.

  17. Analysis of three-dimensional frames using shear-locking free beam elements based on the third-order shear-deformation theory

    E-Print Network [OSTI]

    Shenoy, Raghavendra Konchadi

    2001-01-01T23:59:59.000Z

    In the present research, space frames are studied by incorporating shear-locking-free beam finite element based on the third-order shear deformation theory. Currently, the beam element used in the analysis of frames is based on the Euler...

  18. Evaluation of Wind Shear Patterns at Midwest Wind Energy Facilities: Preprint

    SciTech Connect (OSTI)

    Smith, K.; Randall, G.; Malcolm, D.; Kelley, N.; Smith, B.

    2002-05-01T23:59:59.000Z

    The U.S. Department of Energy-Electric Power Research Institute (DOE-EPRI) Wind Turbine Verification Program (TVP) has included several wind energy facilities in the Midwestern United States. At several of these projects, a strong diurnal shear pattern has been observed. During the day, low and sometimes negative shear has been measured. During night hours, very high positive shear is frequently observed. These high nighttime shear values are of concern due to the potential for high stresses across the rotor. The resulting loads on turbine components could result in failures. Conversely, the effects of high nighttime wind shear could benefit wind generated energy production in the Midwest by providing a source of greater hub-height wind speeds, particularly for multi-megawatt turbines that utilize tall towers. This paper presents an overview of the observed wind shear at each of the Midwest TVP projects, focusing on diurnal patterns and the frequency of very high nighttime shear at the sites. Turbine fault incidence is examined to determine the presence or absence of a correlation to periods of high shear. Implications of shear-related failures are discussed for other Midwest projects that use megawatt-scale turbines. In addition, this paper discusses the importance of accurate shear estimates for project development.

  19. Short-term and creep shear characteristics of a needlepunched thermally locked geosynthetic clay liner

    SciTech Connect (OSTI)

    Siebken, J.R. [National Seal Co., Galesburg, IL (United States). Technical Services; Swan, R.H. Jr.; Yuan, Z. [GeoSyntec Consultants, Atlanta, GA (United States). Soil-Geosynthetic Interaction Testing Lab.

    1997-11-01T23:59:59.000Z

    A series of constant-rate direct shear tests were conducted on a needlepunched thermally locked geosynthetic clay liner (GCL) in accordance with ASTM Test Method for Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and Geosynthetic Friction by the Direct Shear Method (D 5321). The test results demonstrate that the needlepunched thermally locked reinforcing fibers provide substantial short-term shear strength to a GCL. However, there is a growing concern that the long-term shear strength to a GCL. However, there is a growing concern that the long-term shear strength of this type of GCL can be affected due to the potential of creep within the reinforcing fibers under sustained constant loads which occur in the field. An attempt was made to address this concern through an incrementally-loaded creep shear test conducted in a newly developed constant-load (creep) shear testing device. The results of the creep shear test to date show that the GCL has undergone relatively small shear displacements with incremental shear rates decreasing with time within each loading phase.

  20. Fast pulsing of an open research thermionic converter

    SciTech Connect (OSTI)

    Svensson, R. [Coll. of Applied Engineering and Maritime Studies, Goeteborg (Sweden); [Chalmers Univ. of Technology, Goeteborg (Sweden); Holmlid, L. [Univ. of Goeteborg (Sweden). Dept. of Chemistry

    1997-12-31T23:59:59.000Z

    Several experiments concerning anomalous phenomena in an open Thermionic Energy Converter (TEC) have previously been reported. Under certain conditions a very high electron current (back current), flowing from the cold collector to the hot emitter, has been observed. This phenomenon has been studied with various methods. The conclusion is that an excited form of matter, with a very low work function, is located on the collector surface and in the interelectrode space. The matter consists of highly excited cesium atoms in a condensed form, and is referred to as Rydberg matter (RM). The existence of RM has been predicted theoretically by Manykin, et al. The efficiency of the RM TEC varies considerably with parameters such as emitter temperature and collector temperature. There is also a discrepancy between the apparent collector work function when the collector is run as electron emitter and when it is used as an electron collector. From other experiments the authors conclude that negative ions Cs{sup {minus}} will form on the RM surface on the collector. In order to control the effect of possible negative ions, a series of experiments including rapid pulsing of the TEC is in progress. The objective of the pulsing is to use a negative pulse (with respect to the collector) to remove possible negative ions from the RM surface and restore the low work function of the RM surface.

  1. Advanced Gate Drive for the SNS High Voltage Converter Modulator

    SciTech Connect (OSTI)

    Nguyen, M.N.; Burkhart, C.; Kemp, M.A.; /SLAC; Anderson, D.E.; /Oak Ridge

    2009-05-07T23:59:59.000Z

    SLAC National Accelerator Laboratory is developing a next generation H-bridge switch plate [1], a critical component of the SNS High Voltage Converter Modulator [2]. As part of that effort, a new IGBT gate driver has been developed. The drivers are an integral part of the switch plate, which are essential to ensuring fault-tolerant, high-performance operation of the modulator. The redesigned driver improves upon the existing gate drive in several ways. The new gate driver has improved fault detection and suppression capabilities; suppression of shoot-through and over-voltage conditions, monitoring of dI/dt and Vce(sat) for fast over-current detection and suppression, and redundant power isolation are some of the added features. In addition, triggering insertion delay is reduced by a factor of four compared to the existing driver. This paper details the design and performance of the new IGBT gate driver. A simplified schematic and description of the construction are included. The operation of the fast over-current detection circuits, active IGBT over-voltage protection circuit, shoot-through prevention circuitry, and control power isolation breakdown detection circuit are discussed.

  2. Converting acoustic energy into useful other energy forms

    DOE Patents [OSTI]

    Putterman, Seth J. (Sherman Oaks, CA); Barber, Bradley Paul (Northridge, CA); Hiller, Robert Anthony (Los Angeles, CA); Lofstedt, Ritva Maire Johanna (Los Angeles, CA)

    1997-01-01T23:59:59.000Z

    Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

  3. Intensive neutrino source on the base of lithium converter

    E-Print Network [OSTI]

    Lyashuk, V I

    2015-01-01T23:59:59.000Z

    An intensive antineutrino source with a hard spectrum (with energy up to 13 MeV, average energy 6.5 MeV) can be realized on the base of beta-decay of short living isotope 8Li (0.84 s). The 8Li isotope (generated in activation of 7Li isotope) is a prime perspective antineutrino source owing to the hard antineutrino spectrum and square dependence of cross section on the energy. Up today nuclear reactors are the most intensive neutrino sources. Antineutrino reactor spectra have large uncertainties in the summary antineutrino spectrum at energy E>6 MeV. Use of 8Li isotope allows to decrease sharply the uncertainties or to exclude it completely. An intensive neutron fluxes are requested for rapid generation of 8Li isotope. The installations on the base of nuclear reactors can be an alternative for nuclear reactors as traditional neutron sources. It is possible creation of neutrino sources another in principle: on the base of tandem of accelerators, neutron generating targets and lithium converter. An intensive neu...

  4. Digital regulation of a phase controlled power converter

    SciTech Connect (OSTI)

    Schultheiss, C.; Haque, T.

    1995-12-01T23:59:59.000Z

    The Relativistic Heavy Ion Collider, now in construction at Brookhaven National Laboratory, will use phase controlled power converters for the main dipole and quadrupole magnet strings. The rectifiers in these power supplies will be controlled by a digital regulator based on the TI 320C30 Digital Signal Processor (DSP). The DSP implements the current loop, the voltage loop, and a system to actively reduce the sub-harmonic ripple components. Digital firing circuits consisting of a phase locked lop and counters are used to fire the SCRs. Corrections for the sub-harmonic reduction are calculated by the DSP and stored in registers in the firing circuit. These corrections are added in hardware, to the over-all firing count provided by the DSP. the resultant count is compared to a reference counter to fire the SCRs. This combination of a digital control system and the digital firing circuits allows the correction of the sub-harmonics in a real-time sense. A prototype of the regulator has been constructed, and the preliminary testing indicates a sub-harmonic reduction of 60 dB.

  5. A Novel Predictive Inductor Multiplier for Integrated Circuit DC-DC Converters in Portable Applications

    E-Print Network [OSTI]

    Rincon-Mora, Gabriel A.

    that the converter appears to have an induct- ance thirty-eight times the value actually used. Compensating for small voltage. This is a major limitation in very common situations like when a Lithium ion battery in the three is a switched capacitor converter, also called a charge pump. In these topologies, one or more capacitors

  6. The method of creating a small interelectrode spacing in thermionic energy converters

    SciTech Connect (OSTI)

    Kalandarishvili, A.G. [Russian Research Center Kurchatov Inst., Moscow (Russian Federation)

    1996-12-31T23:59:59.000Z

    The method is proposed for creating a small interelectrode spacing in thermionic energy converters (TEC) using graphite-based laminated structures placed inside the converter interelectrode gap. The paper discusses conceptual design and fabrication technology of this device. The proposed method is compared with the methods currently implemented in practice.

  7. Non-Droop Methods for Context-Sensitive Sharing in Multi-Module Switching Converters

    E-Print Network [OSTI]

    Kimball, Jonathan W.

    Non-Droop Methods for Context-Sensitive Sharing in Multi-Module Switching Converters Philip T droop or voltage droop controls support context-sensitive sharing. Droop gains can be set readily is to elucidate non-droop approaches that support context-sensitive sharing in various modular converter

  8. Converter and Inductor Design for Fast-Response Microprocessor Power Delivery

    E-Print Network [OSTI]

    Converter and Inductor Design for Fast-Response Microprocessor Power Delivery G. J. Mehas K. D be obtained from the IEEE. #12;Converter and Inductor Design for Fast-Response Microprocessor Power Delivery such as microprocessor power delivery are analyzed, with an emphasis on the role of the inductor. Opti- mum values

  9. Coordination of Converter and Fuel Cell Controllers Kyung-Won Suh and Anna G. Stefanopoulou

    E-Print Network [OSTI]

    Stefanopoulou, Anna

    , such as an air delivery system which supplies oxygen using a compressor or a blower, a hydrogen delivery system with a compressor and a DC-DC converter. We then employ model-based control techniques to tune two separate controllers for the compressor and the converter. We demonstrate that the lack of communication

  10. Influence of control strategy on the global efficiency of a Direct Wave Energy Converter with

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Influence of control strategy on the global efficiency of a Direct Wave Energy Converter, France Abstract--The choice of control strategy for Direct Wave Energy Converters (DWEC) is often a simple loss model in order to design a better control strategy. Keywords--Wave energy conversion; Point

  11. Development of a Wireless Control and Monitoring System for Wave Energy Converters

    E-Print Network [OSTI]

    Wood, Stephen L.

    Development of a Wireless Control and Monitoring System for Wave Energy Converters Ismail Sultan Control and Monitoring Unit (PCMU) for the design and performance evaluation of wave energy converters (WECs). A prototype PCMU system was successfully deployed on June 8th , 2012 with wave energy convertor

  12. Control of high power IGBT modules in the active region for fast pulsed power converters

    E-Print Network [OSTI]

    Cravero, JM; Garcia Retegui, R; Maestri, S; Uicich, G

    2014-01-01T23:59:59.000Z

    At CERN, fast pulsed power converters are used to supply trapezoidal current in different magnet loads. These converters perform output current regulation by using a high power IGBT module in its ohmic region. This paper presents a new strategy for pulsed current control applications using a specifically designed IGBT driver.

  13. Multi-Stage Converters: A New Technology for Traction Drive Juan W. Dixon

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Católica de Chile)

    demonstrated the feasibility to build multi-stage converters for real electric vehicles or electric buses System". 1. Introduction Power Electronics technologies contribute with important part in the development of electric vehicles. On the other hand, the PWM techniques used today to control modern static converters

  14. FC/Battery Power Management for Electric Vehicle Based Interleaved dc-dc Boost Converter Topology

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    FC/Battery Power Management for Electric Vehicle Based Interleaved dc- dc Boost Converter Topology.fr Keywords Fuel cell System (FCS), Electric vehicle, Energy management, Interleaved Boost DC-DC Converter (FC for electric vehicle may not be feasible to satisfy the peak demand changes especially during accelerations

  15. Regenerative Braking for an Electric Vehicle Using Ultracapacitors and a Buck-Boost Converter

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Católica de Chile)

    Regenerative Braking for an Electric Vehicle Using Ultracapacitors and a Buck-Boost Converter Juan for an Electric Vehicle has been simulated. The purpose of this device is to allow higher accelerations, similar in shape and size to a Chevrolet S-10. This vehicle was already converted to an electric car

  16. Generalized Steady-state Analysis of Multiphase Interleaved Boost Converter with Coupled Inductors

    E-Print Network [OSTI]

    Lipo, Thomas

    2005-38 Generalized Steady-state Analysis of Multiphase Interleaved Boost Converter with Coupled-dong, Masan, Gyeongnam, 631-701, Republic of Korea #12;Generalised steady-state analysis of multiphase.A. Lipo Abstract: The generalised steady-state analysis of the multi-phase interleaved boost converter

  17. Digitally Controlled Distributed Multiphase DC-DC Converters Xu Zhang, Luca Corradini and Dragan Maksimovic

    E-Print Network [OSTI]

    Digitally Controlled Distributed Multiphase DC-DC Converters Xu Zhang, Luca Corradini and Dragan, corradin, maksimov}@colorado.edu Abstract -- This paper describes a distributed master-slave multiphase DC V-to-12 V input, 1.3 V, 20 A output two-phase synchronous buck converter. Index Terms-- Multiphase

  18. Comparison of Two Autonomous AC-DC Converters for Piezoelectric Energy Scavenging Systems

    E-Print Network [OSTI]

    Boyer, Edmond

    - 1 - Comparison of Two Autonomous AC-DC Converters for Piezoelectric Energy Scavenging Systems E Cornaredo, Milan, Italy Abstract - Piezoelectric Energy Scavenging Systems (PESS) are used to convert of the output voltage of these transducers is needed. Since the output power level of the energy transducer can

  19. Sliding Mode Control of Boost Converter: Application to energy storage system via supercapacitors

    E-Print Network [OSTI]

    Boyer, Edmond

    Sliding Mode Control of Boost Converter: Application to energy storage system via supercapacitors of an energy storage system based on supercapacitors technology in order to regulate the output voltage. Given, classical PID controllers are used for the control of power converters [1], [2], [3]. Simple models

  20. Boost Converter Provides Temperature-Controlled Operation of 12V Fan from +5V Supply

    E-Print Network [OSTI]

    McNeill, John A.

    enclosure, and reducing the fan supply voltage when maximum cooling is not necessary. Reducing the operatingBoost Converter Provides Temperature-Controlled Operation of 12V Fan from +5V Supply John Mc converter shown in Fig. 1 allows operation of a 12V brushless DC fan from a +5V supply. The circuit is based

  1. Solar Power To Help Convert Carbon Dioxide Into Fuel : Renewable Energy News

    E-Print Network [OSTI]

    Lovley, Derek

    Solar Power To Help Convert Carbon Dioxide Into Fuel : Renewable Energy News TUESDAY 25 MAY, 2010 | | Solar Power To Help Convert Carbon Dioxide Into Fuel by Energy Matters Microbiologist Derek Lovley dioxide into transportation fuels, with the help of special micro-organisms and solar power. The team

  2. Digital Background Calibration of an Algorithmic Analog-to-Digital Converter

    E-Print Network [OSTI]

    Hurst, Paul J.

    one sample-and-hold amplifier. At a sampling rate of 20 Msamples/s, the peak signal-to-noise-effective design of high-performance analog-to-digital converters with low-performance op amps. In this paper analog-to-digital converter (ADC). To minimize power dissipation and noise, the queue consists of only

  3. Design and development of a DC-DC converter for a fuel cell inverter system

    E-Print Network [OSTI]

    Gopinath, Rajesh

    2001-01-01T23:59:59.000Z

    This thesis outlines the design and development of a DC-DC converter for a fuel cell inverter application. The proposed DC-DC converter was designed and tested at Texas A&M to meet the specifications laid down for the '2001 Future Energy Challenge...

  4. The Valuation of Convertible Bonds With Credit Risk P. A. Forsyth K. R. Vetzal

    E-Print Network [OSTI]

    Forsyth, Peter A.

    The Valuation of Convertible Bonds With Credit Risk E. Ayache P. A. Forsyth K. R. Vetzal April 22 upon the history of its stock price. This paper explores the valuation of convertible bonds subject implicit method to decou- ple the system of linear complementarity problems at each timestep. Numerical

  5. An 8-bit current mode ripple folding analog to digital converter 

    E-Print Network [OSTI]

    Dinc, Huseyin

    2002-01-01T23:59:59.000Z

    Design of an 8-bit current mode, ripple-folding analog to digital (A/D) converter is discussed. The ripple folding technique and the possible implementations in different process technologies are summarized. To have an A/D converter compatible...

  6. Ac-Ac Dual Active Bridge Converter for Solid State Transformer

    E-Print Network [OSTI]

    Kimball, Jonathan W.

    flow. The advantages of direct ac-ac conversion include fewer power conversion stages and minimized single-stage direct ac-ac power conversion to an SST. Fewer conversion stages reduce conduction loss) converter in direct ac-ac power conversion. Like a DAB converter as dc-dc power supply in [5] and [6

  7. Design of high speed low voltage data converters for UWB communication systems

    E-Print Network [OSTI]

    Lee, Choong Hoon

    2006-08-16T23:59:59.000Z

    For A/D converters in ultra-wideband (UWB) communication systems, the flash A/D type is commonly used because of its fast speed and simple architecture. However, the number of comparators in a flash A/D converter exponentially increases...

  8. An 8-bit current mode ripple folding analog to digital converter

    E-Print Network [OSTI]

    Dinc, Huseyin

    2002-01-01T23:59:59.000Z

    Design of an 8-bit current mode, ripple-folding analog to digital (A/D) converter is discussed. The ripple folding technique and the possible implementations in different process technologies are summarized. To have an A/D converter compatible...

  9. A Passivity-Based Controller for coordination of converters in a Fuel Cell System

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and hybrid vehicles has increased since 2009. In this context, the development of a fuel cell (FC) system, , A Passivity-Based Controller for coordination of converters in a Fuel Cell System M. Hilaireta-mail: mickael.hilairet@lgep.supelec.fr Abstract The problem of converters coordination of a fuel cell system

  10. Wide input range DC-DC converter with digital control scheme

    E-Print Network [OSTI]

    Harfman Todorovic, Maja

    2006-04-12T23:59:59.000Z

    In this thesis analysis and design of a wide input range DC-DC converter is proposed along with a robust power control scheme. The proposed converter and its control is designed to be compatible to a fuel cell power source, which exhibits 2...

  11. FLATNESS BASED CONTROL OF A BUCK-CONVERTER DRIVEN DC MOTOR

    E-Print Network [OSTI]

    Knobloch,Jürgen

    FLATNESS BASED CONTROL OF A BUCK-CONVERTER DRIVEN DC MOTOR Felix Antritter ,1 Peter Maurer Johann on the circuit and control design of a buck converter driven DC motor. The steps of design, as for example objective: tracking control of the DC motor's shaft angular velocity. The dynamic system composed from

  12. MODULAR MULTI-LEVEL CONVERTER BASED HVDC SYSTEM FOR GRID CONNECTION OF OFFSHORE WIND

    E-Print Network [OSTI]

    Chaudhary, Sanjay

    MODULAR MULTI-LEVEL CONVERTER BASED HVDC SYSTEM FOR GRID CONNECTION OF OFFSHORE WIND POWER PLANT U off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter offshore wind power plants (WPP) because they offer higher energy yield due to a superior wind profile

  13. Ga{sub x}In{sub 1{minus}x}As thermophotovoltaic converters

    SciTech Connect (OSTI)

    Wanlass, M.W.; Ward, J.S.; Emery, K.A.; Coutts, T.J. [National Renewable Energy Lab., Golden, CO (United States)

    1994-12-31T23:59:59.000Z

    Preliminary research into the development of single-junction Ga{sub x}In{sub 1{minus}x}As thermophotovoltaic (TPV) power converters is reviewed. The devices structures are grown epitaxially on single-crystal InP substrates. Converter band gaps of 0.50--0.74 eV have been considered in accordance with modeling calculations. A 1-sun, AMO efficiency of 12.8% is reported for a lattice-matched, 0.74-eV converter. Converters with lower band gaps are fabricated using lattice-mismatched, compositionally graded structures. Functional TPV converters with good performance characteristics have been demonstrated for band gaps as low as 0.5 eV.

  14. Utility-Scale Power Router: Dynamic Control of Grid Assets Using Direct AC Converter Cells

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    ADEPT Project: Georgia Tech is developing a cost-effective, utility-scale power router that uses an enhanced transformer to more efficiently direct power on the grid. Existing power routing technologies are too expensive for widespread use, but the ability to route grid power to match real-time demand and power outages would significantly reduce energy costs for utilities, municipalities, and consumers. Georgia Tech is adding a power converter to an existing grid transformer to better control power flows at about 1/10th the cost of existing power routing solutions. Transformers convert the high-voltage electricity that is transmitted through the grid into the low-voltage electricity that is used by homes and businesses. The added converter uses fewer steps to convert some types of power and eliminates unnecessary power storage, among other improvements. The enhanced transformer is more efficient, and it would still work even if the converter fails, ensuring grid reliability.

  15. Compact self-contained electrical-to-optical converter/transmitter

    SciTech Connect (OSTI)

    Seligmann, D.A.; Moss, W.C.; Valk, T.C.; Conder, A.D.

    1992-12-31T23:59:59.000Z

    An electrical-to-optical converter/transmitter is disclosed. A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch means.

  16. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOE Patents [OSTI]

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09T23:59:59.000Z

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  17. Analysis of PS-converted wave seismic data in the presence of azimuthal anisotropy 

    E-Print Network [OSTI]

    Liu, Weining

    2014-11-27T23:59:59.000Z

    Shear-wave splitting and azimuthal variations of seismic attributes are two major anisotropic effects induced by vertically-aligned fractures. They both have influences on seismic data processing and interpretation, and ...

  18. Bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics at RHIC

    E-Print Network [OSTI]

    J. Noronha-Hostler; J. Noronha; F. Grassi

    2014-06-19T23:59:59.000Z

    The interplay between shear and bulk viscosities on the flow harmonics, $v_n$'s, at RHIC is investigated using the newly developed relativistic 2+1 hydrodynamical code v-USPhydro that includes bulk and shear viscosity effects both in the hydrodynamic evolution and also at freeze-out. While shear viscosity is known to attenuate the flow harmonics, we find that the inclusion of bulk viscosity decreases the shear viscosity-induced suppression of the flow harmonics bringing them closer to their values in ideal hydrodynamical calculations. Depending on the value of the bulk viscosity to entropy density ratio, $\\zeta/s$, in the quark-gluon plasma, the bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics may require a re-evaluation of the previous estimates of the shear viscosity to entropy density ratio, $\\eta/s$, of the quark-gluon plasma previously extracted by comparing hydrodynamic calculations to heavy ion data.

  19. Study of Power Converter Topologies with Energy Recovery and grid power flow control Part B: boost converter with energy storage

    E-Print Network [OSTI]

    Rogelio, Garcia Retegui; Gustavo, Uicich; Mario, Benedetti; Gilles, Le Godec; Konstantinos, Papastergiou

    2015-01-01T23:59:59.000Z

    In the framework of a Transfer line (TT2) Consolidation Programme, a number of studies on Energy cycling have been commissioned. Part of this work involves the study of dierent power electronic system topologies for magnet energy recovery. In this report, the use of a boost front-end converter supplying DC link of a 4-quadrant magnet supply is analysed. The key objective of the study is to find control strategies that result in the control of the peak power required from the power network as well as to recover the magnet energy into capacitor banks with controlled voltage fluctuation. The study comprises the modelling of the system by means of the method of state averaging and the development of regulation strategies to energy management. The proposed control strategies can be divided in two groups: in the first group, the magnet current is used to define the reference for the control system, while in the second group this current is unknown and some strategies are devised to limit the power drawn from the el...

  20. Design and analysis of a zero-voltage switching scheme for a dc- to-dc converter

    E-Print Network [OSTI]

    Arun, G.

    1992-01-01T23:59:59.000Z

    5S 59 VITA . 65 I. IST OF FICI;RES FIGURE Page Linear versus switch-mode power convers&on Components of a switch-mode dc-to-dc converter 3 A typical dc-to-dc converter system Basic buck converter Basic boost converter Basic buck...-boost converter 7 One leg of a, dc-to-dc converter. Turn-on and turn-off scenartos in switch-mode operation. 16 10 Switching loci in the ur ? ir plane. Circuit for. zero-voltage sw&tching. . Mode 1 17 90 Mode? Mode I Mode 5 oo 93 Typical voltage...

  1. Shear viscosity and chemical equilibration of the QGP

    E-Print Network [OSTI]

    Salvatore Plumari; Armando Puglisi; Maria Colonna; Francesco Scardina; Vincenzo Greco

    2012-09-04T23:59:59.000Z

    We have investigated, in the frame work of the transport approach, different aspects of the QGP created in Heavy Ion Collisions at RHIC and LHC energies. The shear viscosity $\\eta$ has been calculated by using the Green-Kubo relation at the cascade level. We have compared the numerical results for $\\eta$ obtained from the Green-Kubo correlator with the analytical formula in both the Relaxation Time Approximation (RTA) and the Chapman-Enskog approximation (CE). From this comparison we show that in the range of temperature explored in a Heavy Ion collision the RTA underestimates the viscosity by about a factor of 2, while a good agreement is found between the CE approximation and Gree-Kubo relation already at first order of approximation. The agreement with the CE approximation supplies an analytical formula that allows to develop kinetic transport theory at fixed shear viscosity to entropy density ratio, $\\eta/s$. We show some results for the build up of anisotropic flows $v_{2}$ in a transport approach at fixed shear viscosity to entropy density ratio, $\\eta/s$. We study the impact of a T-dependent $\\eta/s(T)$ on the generation of the elliptic flows at both RHIC and LHC. We show that the transport approach provides, in a unified way, a tool able to naturally describe the $v_{2}(p_{T})$ in a wide range of $p_{T}$, including also the description of the rise and fall and saturation of the $v_{2}(p_{T})$ observed at LHC. Finally, we have studied the evolution of the quark-gluon composition employing a Boltzmann-Vlasov transport approach that include: the mean fields dynamics, associated to the quasi-particle model, and the elastic and inelastic collisions for massive quarks and gluons. Following the chemical evolution from an initial gluon dominated plasma we predict a quark dominance close to $T_{C}$ paving the way to an hadronization via quark coalescence.

  2. Wind shear for large wind turbine generators at selected tall tower sites

    SciTech Connect (OSTI)

    Elliott, D.L.

    1984-04-01T23:59:59.000Z

    The objective of the study described in this report is to examine the nature of wind shear profiles and their variability over the height of large horizontal-axis wind turbines and to provide information on wind shear relevant to the design and opertion of large wind turbines. Wind turbine fatigue life and power quality are related through the forcing functions on the blade to the shapes of the wind shear profiles and their fluctuations over the disk of rotation.

  3. Standard Test Method for Shear Strength of Fusion Bonded Polycarbonate Aerospace Glazing Material

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    1995-01-01T23:59:59.000Z

    1.1 This test method determines the shear yield strength Fsy and shear ultimate strength Fsu of fusion bonds in polycarbonate by applying torsional shear loads to the fusion-bond line. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Hard discs under steady shear: comparison of Brownian dynamics simulations and mode coupling theory

    E-Print Network [OSTI]

    O. Henrich; F. Weysser; M. E. Cates; M. Fuchs

    2010-01-19T23:59:59.000Z

    Brownian dynamics simulations of bidisperse hard discs moving in two dimensions in a given steady and homogeneous shear flow are presented close to and above the glasstransition density. The stationary structure functions and stresses of shear-melted glass are compared quantitatively to parameter-free numerical calculations of monodisperse hard discs using mode coupling theory within the integration through transients framework. Theory qualitatively explains the properties of the yielding glass but quantitatively overestimatesthe shear-driven stresses and structural anisotropies.

  5. Electron Trapping in Shear Alfven Waves that Power the Aurora

    SciTech Connect (OSTI)

    Watt, Clare E. J.; Rankin, Robert [University of Alberta, Edmonton, Alberta (Canada)

    2009-01-30T23:59:59.000Z

    Results from 1D Vlasov drift-kinetic plasma simulations reveal how and where auroral electrons are accelerated along Earth's geomagnetic field. In the warm plasma sheet, electrons become trapped in shear Alfven waves, preventing immediate wave damping. As waves move to regions with larger v{sub Te}/v{sub A}, their parallel electric field decreases, and the trapped electrons escape their influence. The resulting electron distribution functions compare favorably with in situ observations, demonstrating for the first time a self-consistent link between Alfven waves and electrons that form aurora.

  6. Self-sustained oscillations in homogeneous shear flow

    E-Print Network [OSTI]

    Victor Yakhot

    2002-06-27T23:59:59.000Z

    Generation of the large-scale coherent vortical structurs in homogeneous shear flow couples dynamical processes of energy and enstrophy production. In the large rate of strain limit, the simple estimates of the contributions to the energy and enstrophy equations result in a dynamical system, describing experimentally and numerically observed self-sustained non-linear oscillations of energy and enstrophy. It is shown that the period of these oscilaltions is independent upon the box size and the energy and enstrophy fluctuations are strongly correlated.

  7. Dissipation and Rheology of Sheared Soft-Core Frictionless Disks

    E-Print Network [OSTI]

    Daniel Vågberg; Peter Olsson; S. Teitel

    2014-09-17T23:59:59.000Z

    We use numerical simulations to investigate the effect of different dissipative models on the shearing rheology of massive soft-core frictionless disks in two dimensions. We show that the presence of Newtonian (overdamped) vs Bagnoldian (inertial) rheology is related to the formation of large connected clusters of disks, and that sharp transitions may exist between the two as system parameters vary. In the limit of strongly inelastic collisions, we find that rheological curves collapse to a well-defined limit when plotted against an appropriate dimensionless strain rate.

  8. Flow of shear induced structure surfactants in porous media

    E-Print Network [OSTI]

    Ramaswamy, Harish B.

    1993-01-01T23:59:59.000Z

    be very useful in extracting oil from heterogeneous formations. In a low permeability region, the Rooding solution would have a lower viscosity snd hence lower resistance, : RODLIKE NONE T]C Fig. 4. Influence of concentration and temperature... measure of the elasticity of the fluid. There is some evidence of a change in the normal stress data at the shear rates at which the viscosity curves indicated the SIS state, though the change is minor as compared with that of the viscosity data. 26...

  9. SSI response of a typical shear wall structure. Volume 1

    SciTech Connect (OSTI)

    Johnson, J.J.; Schewe, E.C.; Maslenikov, O.R.

    1984-04-01T23:59:59.000Z

    The Simplified Methods project of the US NRC-funded Seismic Safety Margins Research Program (SSMRP) has as its goal the development of a methodology to perform routine seismic probabilistic risk assessments of commercial nuclear power plants. The study reported here develops calibration factors to relate best estimate response to design values accounting for approximations and simplifications in SSI analysis procedures. Nineteen cases were analyzed and in-structure response compared. The structure of interest was a typical shear wall structure. 6 references, 44 figures, 22 tables.

  10. Damping of Neutron Star Shear Modes by Superfluid Friction

    E-Print Network [OSTI]

    P. B. Jones

    2003-01-07T23:59:59.000Z

    The forced motion of superfluid vortices in shear oscillations of rotating solid neutron star matter produces damping of the mode. A simple model of the unpinning and repinning processes is described, with numerical calculations of the consequent energy decay times. These are of the order of 1 s or more for typical anomalous X-ray pulsars but become very short for the general population of radio pulsars. The superfluid friction processes considered here may also be significant for the damping of r-modes in rapidly rotating neutron stars.

  11. Characterization of geothermal reservoir crack patterns using shear-wave

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty EditCalifornia:PowerCER.png El CER es una instituciónBy Shear-Wave Splittingsplitting

  12. Estimating Undrained Strength of Clays from Direct Shear Testing at Fast Displacement Rates

    E-Print Network [OSTI]

    Bro, Andrew D; Stewart, Jonathan P; Pradel, Daniel E

    2013-01-01T23:59:59.000Z

    for stability of soft clays,” J. Geotech. Engrg. , ASCE,behavior of saturated clay,” J. Geotech. Engrg. , ASCE,Undrained Strength of Clays from Direct Shear Testing at

  13. Pitch Error and Shear Web Disbond Detection on Wind Turbine Blades...

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

    American Institute of Aeronautics and Astronautics 1 Pitch Error and Shear Web Disbond Detection on Wind Turbine Blades for Offshore Structural Health and Prognostics Management...

  14. XIAP is essential for shear stress-enhanced Tyr-576 phosphorylation of FAK

    SciTech Connect (OSTI)

    Ahn, Sunyoung [Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, 126, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do, 448-701 (Korea, Republic of)] [Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, 126, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do, 448-701 (Korea, Republic of); Park, Heonyong, E-mail: heonyong@dankook.ac.kr [Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, 126, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do, 448-701 (Korea, Republic of)] [Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook Univiersity, 126, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do, 448-701 (Korea, Republic of)

    2010-08-20T23:59:59.000Z

    Research highlights: {yields} Laminar shear stress phosphorylates Tyr-576 in FAK. {yields} XIAP is essential for shear stress-induced phosphorylation of Tyr-576. {yields} XIAP knockdown induces shear stress-triggered translocation of FAK into nucleus. {yields} XIAP regulates ERK activation by maintaining the Src-accessible location of FAK. -- Abstract: In endothelial cells, X-chromosome linked inhibitor of apoptosis protein (XIAP) regulates cell survival, migration and adhesion. We have recently found that XIAP recruits focal adhesion kinase (FAK) into integrin-associated focal adhesions, controlling cell migration. However, little is understood about the molecular mechanisms by which FAK modulation is controlled by XIAP. In this study, we show that XIAP modulates FAK activity through the control of FAK phosphorylation. In bovine aortic endothelial cells (BAEC), phosphorylation of Tyr-576 in FAK is elevated by laminar shear stress. This elevated phosphorylation appears to be responsible for shear stress-stimulated ERK activation. We found that XIAP knockdown reduces shear stress-enhanced phosphorylation of Tyr-576 and induces shear stress-triggered translocation of FAK into nucleus. Nuclear translocation of FAK reduces contact between FAK and Src, a kinase which phosphorylates Tyr-576. This spatial segregation of FAK from Src decreases Tyr-576 phosphorylation and thus shear-stimulated ERK activation. Taken together, our results demonstrate that XIAP plays a key role in shear stress-stimulated ERK activation by maintaining the Src-accessible location of FAK.

  15. Free magnetohydrodynamic shear layers in the presence of rotation and magnetic field

    SciTech Connect (OSTI)

    Spence, E. J.; Roach, A. H.; Edlund, E. M.; Sloboda, P.; Ji, H. [Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas and Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2012-05-15T23:59:59.000Z

    We present an experimental and numerical study of hydrodynamic and magnetohydrodynamic free shear layers and their stability. We first examine the experimental measurement of globally unstable hydrodynamic shear layers in the presence of rotation and their range of instability. These are compared to numerical simulations, which are used to explain the modification of the shear layer, and thus the critical Rossby number for stability. Magnetic fields are then applied to these scenarios and globally unstable magnetohydrodynamic shear layers generated. These too are compared to numerical simulations showing behavior consistent with the hydrodynamic case and previously reported measurements.

  16. Free MHD Shear Layers In The Presence Of Rotation And Magnetic Field

    SciTech Connect (OSTI)

    E.J. Spence, A.H. Roach, E.M. Edlund, P. Sloboda and H. Ji

    2012-03-20T23:59:59.000Z

    We present an experimental and numerical study of hydrodynamic and magnetohydrodynamic free shear layers and their stability. We first examine the experimental measurement of globally unstable hydrodynamic shear layers in the presence of rotation, and their range of instability. These are compared to numerical simulations, which are used to explain the modification of the shear layer and thus the critical Rossby number for stability. Magnetic fields are then applied to these scenarios, and globally unstable magnetohydrodynamic shear layers generated. These too are compared to numerical simulations, showing behavior consistent with the hydrodynamic case and previously reported measurements.

  17. Wind Shear and Turbulence Profiles at Elevated Heights: Great Lakes and Midwest Sites (Poster)

    SciTech Connect (OSTI)

    Elliott, D.; Schwartz, M.; Scott, G.

    2009-05-01T23:59:59.000Z

    Analyzed wind resource characteristics at elevated heights (50 m-200+m) incuding shear and turbulence profiles for some areas of the Great Lakes and M idwest sites.

  18. Shear-wave splitting as a tool for the characterization of geothermal...

    Open Energy Info (EERE)

    to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Shear-wave splitting as a tool for the characterization of geothermal fractured reservoirs:...

  19. Lift and down-gradient shear-induced diffusion in Red Blood Cell suspensions

    E-Print Network [OSTI]

    Xavier Grandchamp; Gwennou Coupier; Aparna Srivastav; Christophe Minetti; Thomas Podgorski

    2013-02-24T23:59:59.000Z

    The distribution of Red Blood Cells in a confined channel flow is inhomogeneous and shows a marked depletion near the walls due to a competition between migration away from the walls and shear-induced diffusion resulting from interactions between particles. We investigated the lift of RBCs in a shear flow near a wall and measured a significant lift velocity despite the tumbling motion of cells. We also provide values for the collective and anisotropic shear-induced diffusion of a cloud of RBCs, both in the direction of shear and in the direction of vorticity. A generic down-gradient subdiffusion characterized by an exponent 1/3 is highlighted.

  20. Damage to HDPE geomembrane from interface shear over gravelly compacted clay liner

    E-Print Network [OSTI]

    Thielmann, Stuart

    2012-01-01T23:59:59.000Z

    strength of three geosynthetic clay liners,” Journal ofperformance of geosynthetic clay liners under gravel coverShear Machine for Geosynthetic Clay Liners,” Geotechnical