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1

BIOLOGY PROGRAMME ADVISORS Edna Staples LSC 6089 494.2464 Edna.Staples@dal.ca  

E-Print Network [OSTI]

BIOLOGY PROGRAMME ADVISORS Edna Staples LSC 6089 494.2464 Edna.Staples@dal.ca Jennifer Van Dommelen LSC 813 494.1584 Jvandomm@dal.ca Todd Bishop LSC 2089 494.1696 Todd.Bishop@dal.ca BIOLOGY MAJOR (20 credit or 15 credit concentration) Christine Beauchamp LSC 4015 494.2045 Christine.Beauchamp@dal.ca

Gunawardena, Arunika

2

LSC MASTER PLAN THE NEXT 50 YEARS UPDATED SPRING 2010  

E-Print Network [OSTI]

· Sustainable design & energy efficiency to decrease building operating costs #12;RECENT/CURRENT STUDENT CENTER spaces · Clarify circulation in the LSC · Upgrade building infrastructure to be sustainable & supportive Include: · ADA accessibility · LEED certification (sustainable design & construction principles

3

United States Geological Survey, LSC | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of InspectorConcentrating SolarElectric Coop,Save Energy Now Jump(EC-LEDS)Agriculture Name: UnitedSurvey, LSC

4

Cornell's (LSC) project began providing 16,000 tons of cooling (1 ton of cooling = 12,000 Btu/hr, or approximately one large residential window air conditioner) to Cornell University's Ithaca  

E-Print Network [OSTI]

window air conditioner) to Cornell University's Ithaca campus in July of 2000. This project has almost completely replaced mechanical refrigeration for the Cornell district cooling system with the following benefits: · Greater LSC has replaced

Keinan, Alon

5

HOW GOOD ARE SLICING FLOORPLANS? F. Y. Young and D.F. Wong  

E-Print Network [OSTI]

with flexibility in shape, we show that there exists a slicing floorplan F such that area(F) 5 min{(l + & ), 2, (1 + cr)}Atotoz where Atotal is the total area of all the modules, A,,, is the maximum module area, (Y= J floorplans. As a re- sult, slicing floorplans are used in many existing floorplan- ning systems [4, 3, 6, 51

Young, Evangeline Fun Yu

6

Net Balanced Floorplanning Based on Elastic Energy Model  

E-Print Network [OSTI]

Net Balanced Floorplanning Based on Elastic Energy Model Wei Liu and Alberto Nannarelli Dept variations can introduce extra signal skew, it is desirable to have floorplans with balanced net delays based on the elastic energy model. The B*-tree, which is based on an ordered binary tree, is used

Nannarelli, Alberto

7

Temperature Aware Microprocessor Floorplanning Considering Application Dependent Power Load  

E-Print Network [OSTI]

heat diffusion model taking into account the ap- plication dependent power load for thermal analysis is calculated to evaluate each new floorplan, which is time-consuming. [7] proposed a simple deterministic heatTemperature Aware Microprocessor Floorplanning Considering Application Dependent Power Load Chun

He, Lei

8

A Theoretical Upper Bound for IP-Based Floorplanning Guowu Yang1, Xiaoyu Song1, Hannah H. Yang2, and Fei Xie3  

E-Print Network [OSTI]

Amax, and shape flexibility r 2.25, there exists a slic- ing floorplan F of these modules such that Area(F) min{1.131,(1+)}Atotal, where = Amax 2rAtotal . Our results ameliorate the existing best

Xie, Fei

9

Chromium (III), Titanium (III), and Vanadium (IV) sensitization of rare earth complexes for luminescent solar concentrator applications  

E-Print Network [OSTI]

High optical concentrations without excess heating in a stationary system can be achieved with a luminescent solar concentrator (LSC). Neodymium (Nd) and ytterbium (Yb) are excellent infrared LSC materials: inexpensive, ...

Thompson, Nicholas John

2011-01-01T23:59:59.000Z

10

Efficiency enhancement of luminescent solar concentrations for photovoltaic technologies  

E-Print Network [OSTI]

and V.U. Ho?mann. Photovoltaic Solar Energy Gen- eration.stacked LSC plates for photovoltaics with the green LSC onsolar concentra- tors for photovoltaics. Science, 321(5886):

Wang, Chunhua

2011-01-01T23:59:59.000Z

11

Chemical Heterogeneities on La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3??] Thin Films--Correlations to Cathode Surface Activity and Stability  

E-Print Network [OSTI]

La[subscript 0.6]Sr[subscript 0.4]CoO[subscript 3??](LSC) thin film cathodes synthesized by pulsed laser deposition at 450C (LSC_450C) and 650C (LSC_650C) exhibit different electrochemical performance. The origin of ...

Cai, Zhuhua

12

B174 Floorplan  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformationCenterResearch HighlightsTools PrintableCARIBUAuthorCausalityAwardResponsiveB

13

Accelerated Analyte Uptake on Single Beads in Microliter-scale...  

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

the plutonium remaining in solution after specific elapsed time intervals, using liquid scintillation counting (LSC) for nanomolar concentrations and thermal ionization mass...

14

ELECTRICAL & COMPUTER ENGINEERING  

E-Print Network [OSTI]

ELECTRICAL & COMPUTER ENGINEERING SEMINAR "Considerations for Curriculum Planning and Computer Engineering Colorado State University Monday, Feb. 20, 2012, 11:00 a.m. Location: LSC 210 Abstract

15

Session Title What Can an Education Abroad Teach Our Future Leaders About Sustainability?  

E-Print Network [OSTI]

2:30 - 4 p.m. LSC Grey Rock Organizer and Moderator Laura Thornes Methods in Belize Rodolfo Valdes-Vasquez Assistant Professor

Barnes, Elizabeth A.

16

Mechanism for enhanced oxygen reduction kinetics at the (La,Sr)CoO3??/(La,Sr)2CoO4+? hetero-interface  

E-Print Network [OSTI]

The recently reported fast oxygen reduction kinetics at the interface of (La,Sr)CoO3?? (LSC113) and (La,Sr)2CoO4+? (LSC214) phases opened up new questions for the potential role of dissimilar interfaces in advanced cathodes ...

Han, Jeong Woo

17

Collective behavior of semiconductor nanoparticles for use in solar energy harvesting  

E-Print Network [OSTI]

the power conversion efficiency (PCE) of the device. In thismetric, we calculate the PCE for our samples as the ratio ofLSC. The PbS sample has a PCE of 3.2%, comparable to that of

Shcherbatyuk, Georgiy

2012-01-01T23:59:59.000Z

18

Dye-doped polymer nanoparticles for flexible, bulk luminescent solar concentrators  

E-Print Network [OSTI]

Bulk luminescent solar concentrators (LSC) cannot make use of Forster resonance energy transfer (FRET) due to necessarily low dye concentrations. In this thesis, we attempt to present a poly-vinylalcohol (PVA) waveguide ...

Rosenberg, Ron, S.B. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

19

ADAPTIVE REGULARIZED SELF-CONSISTENT FIELD ITERATION ...  

E-Print Network [OSTI]

Department of Mathematics, MOE-LSC and Institute of Natural Sciences, Shanghai Jiaotong University, China. (zw2109@sjtu.edu.cn). Research ...... [9] P. Hohenberg and W. Kohn, Inhomogeneous electron gas, Phys. Rev., 136 (1964), pp.

2012-10-08T23:59:59.000Z

20

Efficiency enhancement of luminescent solar concentrations for photovoltaic technologies  

E-Print Network [OSTI]

parts of the solar spectrum, the power output of the LSC PVson our lab. The power output of the solar simulator is aboutinput solar radiation, the higher the power output. Solar

Wang, Chunhua

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lsc floorplan lsc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Engineering Exploration Day Schedule 8:00 a.m. -9:00 a.m. -Registration/Check-In Lory Student Center 228 (All Tracks)  

E-Print Network [OSTI]

Interactive Medical Exercise Robot) ENGR B106 Engineering Science Overview Dr. Thomas Siller, Associate-Ozbek, Assistant Professor LSC 224-6 Environmental Engineering Lab Water Quality Teaching Lab 268 SCOTT

22

E-Print Network 3.0 - alpha-spectrometry vliyanie toriya Sample...  

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

by activity determination using combinations of LSC, alpha spectrometry or ICP-MS. Uranium... Extraction with TBP from 8 M HNO3, rinse with 1.2 M HCl and elution with water...

23

Linearized semiclassical initial value time correlation functions with maximum entropy analytic continuation  

SciTech Connect (OSTI)

The maximum entropy analytic continuation (MEAC) method is used to extend the range of accuracy of the linearized semiclassical initial value representation (LSC-IVR)/classical Wigner approximation for real time correlation functions. The LSC-IVR provides a very effective 'prior' for the MEAC procedure since it is very good for short times, exact for all time and temperature for harmonic potentials (even for correlation functions of nonlinear operators), and becomes exact in the classical high temperature limit. This combined MEAC+LSC/IVR approach is applied here to two highly nonlinear dynamical systems, a pure quartic potential in one dimensional and liquid para-hydrogen at two thermal state points (25K and 14K under nearly zero external pressure). The former example shows the MEAC procedure to be a very significant enhancement of the LSC-IVR, for correlation functions of both linear and nonlinear operators, and especially at low temperature where semiclassical approximations are least accurate. For liquid para-hydrogen, the LSC-IVR is seen already to be excellent at T = 25K, but the MEAC procedure produces a significant correction at the lower temperature (T = 14K). Comparisons are also made to how the MEAC procedure is able to provide corrections for other trajectory-based dynamical approximations when used as priors.

Liu, Jian; Miller, William H.

2008-08-01T23:59:59.000Z

24

Standardization of 18F by Digital beta(LS)-gamma Coincidence Counting  

E-Print Network [OSTI]

The nuclide 18F disintegrates to 18O by beta+ emission (96.86%) and electron capture (3.14%) with a half-life of 1.8288 h. It is widely used in nuclear medicine for positron emission tomography (PET). Because of its short half-life this nuclide requires the development of fast measuring methods to be standardized. The combination of LSC methods with digital techniques proves to be a good alternative to get low uncertainties for this, and other, short lived nuclides. A radioactive solution of 18F has been standardized by coincidence counting with a LSC, using the logical sum of double coincidences in a TDCR array and a NaI scintillation detector. The results show good consistency with other techniques like 4Pi gamma and LSC.

Rodrigues D.; Balpardo C.; Cassette P.; Arenillas P.; Capoulat M. E.; Ceruti G.; Garca-Torao E

2010-12-17T23:59:59.000Z

25

Lighting system combining daylight concentrators and an artificial source  

DOE Patents [OSTI]

A combined lighting system for a building interior includes a stack of luminescent solar concentrators (LSC), an optical conduit made of preferably optical fibers for transmitting daylight from the LSC stack, a collimating lens set at an angle, a fixture for receiving the daylight at one end and for distributing the daylight as illumination inside the building, an artificial light source at the other end of the fixture for directing artifical light into the fixture for distribution as illumination inside the building, an automatic dimmer/brightener for the artificial light source, and a daylight sensor positioned near to the LSC stack for controlling the automatic dimmer/brightener in response to the daylight sensed. The system also has a reflector positioned behind the artificial light source and a fan for exhausting heated air out of the fixture during summer and for forcing heated air into the fixture for passage into the building interior during winter.

Bornstein, Jonathan G. (Miami, FL); Friedman, Peter S. (Toledo, OH)

1985-01-01T23:59:59.000Z

26

Full Spectrum Diffused and Beamed Solar Energy Application Using Optical Fibre  

E-Print Network [OSTI]

Existing solar energy application systems use small fraction of full spectrum of solar energy. So attempts are made to show how full spectrum solar energy can be used for diffused and beamed form of incident solar energy. Luminescent Solar Concentrator (LSC) principle with optical fibre in diffused sun light and dielectric mirror separation technique with optical fibre in beamed form are discussed. Comparison of both the cases are done. Keywords: full spectrum, solar photonics, diffused solar energy, beamed solar energy, LSC, dielectric mirror, optical fibre, Photo-Voltaic

Dutta Majumdar, M R

2007-01-01T23:59:59.000Z

27

QUANTITATIVE STABILITY ANALYSIS OF STOCHASTIC ...  

E-Print Network [OSTI]

? is said to be lower semi-continuous (lsc for short) at x ? X if and only if ..... It is also known as a distance of probability measures having ?-structure, see [45] ...... In order to compare the previous novel stability result for two-stage models ...... Quantitative stability in stochastic programming: The method of probability metrics...

2013-07-14T23:59:59.000Z

28

Isotope-labeled immunoassays without radiation waste  

E-Print Network [OSTI]

of California, Davis, CA 95616; and Center for Accelerator Mass Spectrometry, Lawrence Livermore National, such as liquid scintillation counting (LSC) and autoradiography, use the radiation generated in the isotope in areas such as environmental monitoring and food analysis. Accelerator mass spectrometry (AMS) developed

Hammock, Bruce D.

29

Report on the Climate Change Plan Feedback Survey November 2010 Dalhousie Office of Sustainability  

E-Print Network [OSTI]

% of them questioned the effectiveness of carbon offsets. Some of the other themes included suggestions for carpooling strategies, solar energy technology for the LSC, charging a carbon offset charge to students Environment Carbon Offsets & Sinks #12;Which of these groups do you currently belong to? Figure 2. Number

Brownstone, Rob

30

Cycling and Transit Green Buildings  

E-Print Network [OSTI]

solar thermal panels at the LSC. 2. Solar wall on the Mona Campbell Bld. 3. 80 solar Photovoltaic (PV) panels installed in front of a solar wall system on the roof of the Computer Science Bld. Water Green Buildings Renewable Energy 1. Solar Thermal and PV Panels are mounted on C Building for research

Lotze, Heike K.

31

Trade-off Analysis of Regenerative Power Source for Long Duration Loitering Airship  

E-Print Network [OSTI]

: photovoltaic flat panels, thin film photovoltaic panels, trough solar concentrators, Stirling dish solar by their excessive drag. Flat solar technologies (i.e. thin film, LSC, and flat panel PV) are ranked the highest, the airship needs a reliable, low-weight, renewable power generation system. This analysis is focused on solar

32

M E M O R A N D U M TO: Faculty, Staff and Students in the College of Pharmacy and Nutrition  

E-Print Network [OSTI]

of policies, procedures and processes to assist members of the University community to managing HSE issues.usask.ca/ohc/LSC/WRS%20Nov%202004.pdf. · University's Health, Safety and Environment Management System (HSEMS) ­ is a set of College facilities, appropriate HSE training courses taken). We are also working to develop a culture

Saskatchewan, University of

33

Nov. 21, 1999 Neutron Irradiation Tests of an S-LINK-over-G-link System  

E-Print Network [OSTI]

Nov. 21, 1999 Neutron Irradiation Tests of an S-LINK-over-G-link System K. Anderson, J. Pilcher, H, MD 1. Objective This note describes neutron irradiation tests of an S-LINK [1] source card (LSC/1024 transmitter/receiver chips operated in 20-bit, single frame mode with a 40 MHz clock. The optical transmitter

34

Test of the consistency of various linearized semiclassical initial value time correlation functions in application to inelastic neutron scattering  

E-Print Network [OSTI]

functions in application to inelastic neutron scattering from liquid para-hydrogen Jian Liua and William H for inelastic neutron scattering from liquid para-hydrogen at 14 K. Various time correlations functions were neutron scattering experimental data all suggest that the LSC-IVR is indeed a good short

Miller, William H.

35

Cathode side hardware for carbonate fuel cells  

DOE Patents [OSTI]

Carbonate fuel cathode side hardware having a thin coating of a conductive ceramic formed from one of LSC (La.sub.0.8Sr.sub.0.2CoO.sub.3) and lithiated NiO (Li.sub.xNiO, where x is 0.1 to 1).

Xu, Gengfu (Danbury, CT); Yuh, Chao-Yi (New Milford, CT)

2011-03-29T23:59:59.000Z

36

Optical design and efficiency improvement for organic luminescent solar concentrators  

E-Print Network [OSTI]

and hybrid photovoltaic/thermal solar conversation systems1 . Generally, an organic LSC is a piece of highly solar energy. We designed, fabricated organic LSCs at different sizes and characterized their optical and electrical properties. The output efficiency enhancement methods for LSCs photovoltaics (PVs) are explored

Hirst, Linda

37

LASER SAFETY COMMITTEE CHARTER November, 2005  

E-Print Network [OSTI]

LASER SAFETY COMMITTEE CHARTER November, 2005 Function The Safety Review Committee (SRC) performs-committees to address specific health and safety matters. The Laser Safety Committee (LSC) is one of the SRC expert sub-committees. The Laser SafetyCommittee recommends policies and practices regarding the conduct and regulatory compliance

Knowles, David William

38

J. Fluid Mech. (2009), vol. 638, pp. 383400. c Cambridge University Press 2009 doi:10.1017/S0022112009991224  

E-Print Network [OSTI]

, amplitude and probability distributions of the displacements. 1. Introduction Rayleigh­B´enard convection of the LSC orientation (Sun, Xi & Xia 2005a; Brown & Ahlers 2006a,b; Xi, Zhou & Xia 2006) and reorientations fluctuations. It has long been observed that there are temperature and velocity oscillations with frequencies

Haller, Gary L.

39

2012 New York State Fair 4-H Energy Robotics Challenge  

E-Print Network [OSTI]

a solar panel (renewable energy source) on a local 4-H facility. § Wind turbine construction-- Your robot down a giant smoke stack and pull coal away from a power plant. § Solar energy ­ Your robot will place the construction" of the lake source cooling heat exchanger. The renewable resource tapped by LSC has reduced

Keinan, Alon

40

CrowdInside: Automatic Construction of Indoor Floorplans Moustafa Alzantot  

E-Print Network [OSTI]

Egypt-Japan Univ. of Sc. and Tech. (E-JUST) Alexandria, Egypt moustafa.alzantot@ejust.edu.eg Moustafa Youssef Wireless Research Center Egypt-Japan Univ. of Sc. and Tech. (E-JUST) Alexandria, Egypt moustafa

Huang, Yan

Note: This page contains sample records for the topic "lsc floorplan lsc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Progress towards Gravitational Wave Astronomy  

E-Print Network [OSTI]

I will review the most recent and interesting results from gravitational wave detection experiments, concentrating on recent results from the LIGO Scientific Collaboration (LSC). I will outline the methodologies utilized in the searches, explain what can be said in the case of a null result, what quantities may be constrained. I will compare these results with prior expectations and discuss their significance. As I go along I will outline the prospects for future improvements.

M. Alessandra Papa

2008-02-07T23:59:59.000Z

42

How Good Are Slicing Floorplans? F.Y. Young and D.F. Wong  

E-Print Network [OSTI]

module area, = q2Amax rAtotal and r 2 is the shape exibility of each module. Our result shows oorplan F of these rectangles such that area(F) minf(1+ 1 bprc) 5 4 (1+ )gAtotal where = q2Amax r the areas are small comparing with the total area, e.g. when r = 2 and Amax = Atotal 100 , the percentage

Young, Evangeline Fun Yu

43

Bus-Aware Microarchitectural Floorplanning Dae Hyun Kim Sung Kyu Lim  

E-Print Network [OSTI]

architects to efficiently tackle issues such as interconnect delay, thermal coupling, etc. On the other hand] by allowing bends in the buses, but this is not suitable for microarchitecture design as it forces, performance and power under thermal constraint. Our thermal analyzer models the heat dissipated by the buses

Lim, Sung Kyu

44

Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes  

SciTech Connect (OSTI)

The goal of this project was to develop an improved understanding of factors governing performance and degradation of mixed-conducting SOFC cathodes. Two new diagnostic tools were developed to help achieve this goal: (1) microelectrode half-cells for improved isolation of cathode impedance on thin electrolytes, and (2) nonlinear electrochemical impedance spectroscopy (NLEIS), a variant of traditional impedance that allows workers to probe nonlinear rates as a function of frequency. After reporting on the development and efficacy of these tools, this document reports on the use of these and other tools to better understand performance and degradation of cathodes based on the mixed conductor La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (LSC) on gadolinia or samaria-doped ceria (GDC or SDC). We describe the use of NLEIS to measure O{sub 2} exchange on thin-film LSC electrodes, and show that O{sub 2} exchange is most likely governed by dissociative adsorption. We also describe parametric studies of porous LSC electrodes using impedance and NLEIS. Our results suggest that O{sub 2} exchange and ion transport co-limit performance under most relevant conditions, but it is O{sub 2} exchange that is most sensitive to processing, and subject to the greatest degradation and sample-to-sample variation. We recommend further work that focuses on electrodes of well-defined or characterized geometry, and probes the details of surface structure, composition, and impurities. Parallel work on primarily electronic conductors (LSM) would also be of benefit to developers, and to improved understanding of surface vs. bulk diffusion.

Stuart Adler; L. Dunyushkina; S. Huff; Y. Lu; J. Wilson

2006-12-31T23:59:59.000Z

45

Background studies for NaI(Tl) detectors in the ANAIS dark matter project  

SciTech Connect (OSTI)

Several large NaI(Tl) detectors, produced by different companies, have been operated in the Canfranc Underground Laboratory (LSC) in the frame of the ANAIS (Annual modulation with NaI Scintillators) project devoted to the direct detection of dark matter. A complete background model has been developed for a 9.6 kg detector (referred as ANAIS-0 prototype) after a long data taking at LSC. Activities from the natural chains of {sup 238}U and {sup 232}Th, and {sup 40}K in the NaI(Tl) crystal were evaluated applying different methods: discrimination of alpha particles vs beta/gamma background by Pulse Shape Analysis for quantifying the content of the natural chains and coincidence techniques for {sup 40}K. Radioactive contaminations in the detector and shielding components were also determined by HPGe spectrometry. Monte Carlo simulations using Geant4 package were carried out to evaluate their contribution. At high energies, most of the measured background is nicely reproduced; at low energy some non-explained components are still present, although some plausible background sources have been analyzed. The {sup 40}K content of the NaI(Tl) crystal has been confirmed to be the dominant contributor to the measured background with this detector. In addition, preliminary results of the background characterization, presently underway at the LSC, of two recently produced NaI(Tl) detectors, with 12.5 kg mass each, will be presented: cosmogenic induced activity has been clearly observed and is being quantified, and {sup 40}K activity at a level ten times lower than in ANAIS-0 has been determined.

Amar, J.; Borjabad, S.; Cebrin, S.; Cuesta, C.; Fortuo, D.; Garca, E.; Ginestra, C.; Gmez, H.; Martnez, M.; Olivn, M. A.; Ortigoza, Y.; Solrzano, A. Ortiz de; Pobes, C.; Puimedn, J.; Sarsa, M. L.; Villar, J. A.; Villar, P. [Laboratorio de Fsica Nuclear y Astropartculas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza, Spain and Laboratorio Subterrneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estacin, Huesca (Spain)] [Laboratorio de Fsica Nuclear y Astropartculas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza, Spain and Laboratorio Subterrneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estacin, Huesca (Spain)

2013-08-08T23:59:59.000Z

46

ACID EVAPORATION OF ULTIMA GOLD TM AB LIQUID SCINTILLATION COCKTAIL RESIDUE  

SciTech Connect (OSTI)

Prior analyses of samples from the F/H Lab solutions showed the presence of diisopropylnapthalene (DIN), a major component of Ultima Gold{trademark} AB liquid scintillation cocktail (LSC). These solutions are processed through H-Canyon Tank 10.5 and ultimately through the 17.8E evaporator. Similar solutions originated in SRNL streams sent to the same H Canyon tanks. This study examined whether the presence of these organics poses a process-significant hazard for the evaporator. Evaporation and calorimetry testing of surrogate samples containing 2000 ppm of Ultima Gold{trademark} AB LSC in 8 M nitric acid have been completed. These experiments showed that although reactions between nitric acid and the organic components do occur, they do not appear to pose a significant hazard for runaway reactions or generation of energetic compounds in canyon evaporators. The amount of off-gas generated was relatively modest and appeared to be well within the venting capacity of the H-Canyon evaporators. A significant fraction of the organic components likely survives the evaporation process primarily as non-volatile components that are not expected to represent any new process concerns during downstream operations such as neutralization. Laboratory Waste solutions containing minor amounts of DIN can be safely received, stored, transferred, and processed through the canyon waste evaporator.

Kyser, E.; Fondeur, F.; Crump, S.

2011-12-21T23:59:59.000Z

47

ANAIS: Status and prospects  

E-Print Network [OSTI]

ANAIS experiment will look for dark matter annual modulation with large mass of ultra-pure NaI(Tl) scintillators at the Canfranc Underground Laboratory (LSC), aiming to confirm the DAMA/LIBRA positive signal in a model-independent way. Two 12.5 kg each NaI(Tl) crystals provided by Alpha Spectra are currently taking data at the LSC. Present status of ANAIS detectors background and general performance is summarized; in particular, thanks to the high light collection efficiency prospects of lowering the threshold down to 1 keVee are reachable. Crystal radiopurity goals are fulfilled for $^{232}$Th and $^{238}$U chains and $^{40}$K activity, although higher than original goal, could be accepted; however, high $^{210}$Pb contamination out-of-equilibrium has been identified. More radiopure detectors are being built by Alpha Spectra. The ongoing high quantum efficiency PMT tests and muon veto characterization are also presented. Finally, the sensitivity of the experiment for the annual modulation in the WIMP signal,...

Amar, Julio; Cuesta, Clara; Garca, Eduardo; Ginestra, Carlos; Martnez, Mara; Olivn, Miguel A; Ortigoza, Ysrael; de Solrzano, Alfonso Ortz; Pobes, Carlos; Puimedn, Jorge; Sarsa, Mara Luisa; Villar, Jos ngel; Villar, Patricia

2015-01-01T23:59:59.000Z

48

Semiclassical (SC) Description of Electronically Non-AdiabaticDynamics via the Initial Value Representation (IVR)  

SciTech Connect (OSTI)

The initial value representation (IVR) of semiclassical (SC) theory is used in conjunction with the Meyer-Miller/Stock-Thoss description of electronic degrees of freedom in order to treat electronically non-adiabatic processes. It is emphasized that the classical equations of motion for the nuclear and electronic degrees of freedom that emerge in this description are precisely the Ehrenfest equations of motion (the force on the nuclei is the force averaged over the electronic wavefunction), but that the trajectories given by these equations of motion do not have the usual shortcomings of the traditional Ehrenfest model when they are used within the SC-IVR framework. For example, in the traditional Ehrenfest model (a mixed quantum-classical approach) the nuclear motion emerges from a non-adiabatic encounter on an average potential energy surface (a weighted average according to the population in the various electronic states), while the SC-IVR describes the correct correlation between electronic and nuclear dynamics, i.e., the nuclear motion is on one potential energy surface or the other depending on the electronic state. Calculations using forward-backward versions of SC-IVR theory (FB-IVR) are presented to illustrate this behavior. An even more approximate version of the SC-IVR, the linearized approximation (LSC-IVR), is slightly better than the traditional Ehrenfest model, but since it cannot describe quantum coherence effects, the LSC-IVR is also not able to describe the correct correlation between nuclear and electronic dynamics.

Ananth, V.; Venkataraman, C.; Miller, W.H.

2007-06-22T23:59:59.000Z

49

Lowering the background level and the energy threshold of Micromegas x-ray detectors for axion searches  

E-Print Network [OSTI]

Axion helioscopes search for solar axions by their conversion in x-rays in the presence of high magnetic fields. The use of low background x-ray detectors is an essential component contributing to the sensitivity of these searches. In this work, we review the recent advances on Micromegas detectors used in the CERN Axion Solar Telescope (CAST) and proposed for the future International Axion Observatory (IAXO). The actual setup in CAST has achieved background levels below 10$^{-6}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$, a factor 100 lower than the first generation of Micromegas detectors. This reduction is based on active and passive shielding techniques, the selection of radiopure materials, offline discrimination techniques and the high granularity of the readout. We describe in detail the background model of the detector, based on its operation at CAST site and at the Canfranc Underground Laboratory (LSC), as well as on Geant4 simulations. The best levels currently achieved at LSC are low than 10$^{-7}$ keV$^{-1}$ ...

Iguaz, F J; Aznar, F; Castel, J F; Dafni, T; Davenport, M; Ferrer-Ribas, E; Galan, J; Garcia, J A; Garza, J G; Giomataris, I; Irastorza, I G; Papaevangelou, T; Rodriguez, A; Tomas, A; Vafeiadis, T; Yildiz, S C

2015-01-01T23:59:59.000Z

50

Lowering the background level and the energy threshold of Micromegas x-ray detectors for axion searches  

E-Print Network [OSTI]

Axion helioscopes search for solar axions by their conversion in x-rays in the presence of high magnetic fields. The use of low background x-ray detectors is an essential component contributing to the sensitivity of these searches. In this work, we review the recent advances on Micromegas detectors used in the CERN Axion Solar Telescope (CAST) and proposed for the future International Axion Observatory (IAXO). The actual setup in CAST has achieved background levels below 10$^{-6}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$, a factor 100 lower than the first generation of Micromegas detectors. This reduction is based on active and passive shielding techniques, the selection of radiopure materials, offline discrimination techniques and the high granularity of the readout. We describe in detail the background model of the detector, based on its operation at CAST site and at the Canfranc Underground Laboratory (LSC), as well as on Geant4 simulations. The best levels currently achieved at LSC are low than 10$^{-7}$ keV$^{-1}$ cm$^{-2}$ s$^{-1}$ and show good prospects for the application of this technology in IAXO. Finally, we present some ideas and results for reducing the energy threshold of these detectors below 1 keV, using high-transparent windows, autotrigger electronics and studying the cluster shape at different energies. As a high flux of axion-like-particles is expected in this energy range, a sub-keV threshold detector could enlarge the physics case of axion helioscopes.

F. J. Iguaz; S. Aune; F. Aznar; J. F. Castel; T. Dafni; M. Davenport; E. Ferrer-Ribas; J. Galan; J. A. Garcia; J. G. Garza; I. Giomataris; I. G. Irastorza; T. Papaevangelou; A. Rodriguez; A. Tomas; T. Vafeiadis; S. C. Yildiz

2015-01-07T23:59:59.000Z

51

Simulation Study of Current Drive Efficiency for KSTAR 5 GHz LHCD  

SciTech Connect (OSTI)

Theoretical 5 GHz lower hybrid current drive (LHCD) efficiency using power spectrum given by 0-D Brambilla code and Lower Hybrid Simulation Code (LSC) have been studied for KSTAR. In LSC simulation, RF-driven current and current drive efficiency has been found to be deeply dependent on the profiles of the plasma density and temperature as well as on current profile in order to obtain hollow current profile favorable for advance tokamak operation mode and steady state operation. The peaked density and broad temperature profile control has been found to be efficient in current drive with maximum RF-driven current larger than 400 kA/MW with very high efficiency when the peak plasma density is ranged from 0.2 to 2.0x1020 m-3, and the peak electron temperature range of 2-20 keV together with toroidal field 2-3.5 T and Ip = 0.5-2 MA. The on-/off-axis current profile controllability is also investigated through parametric scan, and small negative magnetic shear is seen at the narrow region of the off-axis for very high temperature regime and for high BT and I{sub p}. In order to achieve the same for lower temperature regime Ip has to be lower and also for higher LH-power compromising with CD efficiency in this case.

Aria, A. K.; Bae, Y. S.; Yang, H. L.; Kwon, M. [National Fusion Research Institute, Gwahangno 113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Do, H. J.; Namkung, W.; Cho, M. H.; Park, H. [Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang 790-784 (Korea, Republic of)

2011-12-23T23:59:59.000Z

52

90Sr liquid scintillation urine analysis utilizing different approaches for tracer recovery.  

SciTech Connect (OSTI)

90Sr is one of the isotopes most commonly produced by nuclear fission. This medium lived isotope presents serious challenges to radiation workers, the environment, and following a nuclear event, the general public. Methods of identifying this nuclide have been in existence for a number of years (e.g. Horwitz, E.P. [1], Maxwell, S.L.[2], EPA 905.0 [3]) which are time consuming, requiring a month or more for full analysis. This time frame is unacceptable in the present security environment. It is therefore important to have a dependable and rapid method for the determination of Sr. The purposes of this study are to reduce analysis time to less than half a day by utilizing a single method of radiation measurement while continuing to yield precise results. This paper presents findings on three methods that can meet this criteria; (1) stable Sr carrier, (2) 85Sr by gamma spectroscopy, and (3) 85Sr by LSC. Two methods of analyzing and calculating the 85Sr tracer recovery were investigated (gamma spectroscopy and a low energy window-Sr85LEBAB by LSC) as well as the use of two different types of Sr tracer (85Sr and stable Sr carrier). Three separate stock blank urine samples were spiked with various activity levels of 239Pu, 137Cs, 90Sr /90Y to determine the effectiveness of the Eichrome Sr-spec%C2%AE resin 2mL extractive columns. The objective was to compare the recoveries of 85Sr versus a stable strontium carrier, attempt to compare the rate at which samples can be processed by evaluating evaporation, neutralization, and removing the use of another instrument (gamma spectrometer) by using the LSC spectrometer to obtain 85Sr recovery. It was found that when using a calibration curve comprised of a different cocktail and a non-optimum discriminator setting reasonable results (bias of %C2%B1 25%) were achieved. The results from spiked samples containing 85Sr demonstrated that a higher recovery is obtained when using gamma spectroscopy (89-95%) than when using the LEB window from LSC (120-470%). The high recovery for 85Sr by LSC analysis may be due to the interference/cross talk from the alpha region since alpha counts were observed in all sample sets. After further investigation it was determined that the alpha counts were due to 239Pu breakthrough on the Sr-spec%C2%AE column. This requires further development to purify the Sr before an accurate tracer recovery determination can be made. Sample preparation times varied and ranged from 4-6 hours depending on the specific sample preparation process. The results from the spiked samples containing stable strontium nitrate Sr(NO3)2 carrier demonstrate that gravimetric analysis yields the most consistent high recoveries (97-101%) when evaporation is carefully performed. Since this method did not have a variation on the tracer recovery method, the samples were counted in 1) LEB/Alpha/Beta mode optimized for Sr-90, 2) DPM for Sr-90, and 3) general LEB/Alpha/Beta mode. The results (from the known) ranged from 79-104%, 107-177%, and 85-89% for 1, 2, and 3 respectively. Counting the prepared samples in a generic low energy beta/alpha/beta protocol yielded more accurate and consistent results and also yielded the shortest sample preparation turn-around-time of 3.5 hours.

Piraner, Olga [Centers for Disease Control and Prevention, Atlanta, GA; Preston, Rose T. [Sandia Staffing Alliance, LLC, Albuquerque, NM; Shanks, Sonoya Toyoko; Jones, Robert [Centers for Disease Control and Prevention, Atlanta, GA

2010-08-01T23:59:59.000Z

53

SoC Test Scheduling Using the B*-Tree Based Floorplanning Technique * Jen-Yi Wuu1  

E-Print Network [OSTI]

University, Taipei, Taiwan jywuu@eda.ee.ntu.edu.tw, tungchieh@ntu.edu.tw, ywchang@cc.ee.ntu.edu.tw Abstract effective and efficient---our method obtains the best results ever reported for SoC test scheduling

Chang, Yao-Wen

54

E-Print Network 3.0 - analogue fuzzy hardware Sample Search Results  

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

emission inventory neurofuzzy areacontrol class diagnosis identify tumor cubic energy micro... school flicker floorplan friction fusion graphics hardware harmonic highspeed...

55

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Processing of perovskites of LSC, LSF and LSCF composition for evaluation of mechanical properties as a function of environment are begun. The studies are to be in parallel with LSFCO composition to characterize the segregation of cations and slow crack growth in environmental conditions. La{sub 1-x}Sr{sub x}FeO{sub 3-d} has also been characterized for paramagnetic ordering at room temperature and the evolution of magnetic moments as a function of temperature are investigated. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

56

Characterization of Atomic and Electronic Structures of Electrochemically Active SOFC Cathode Surfaces  

SciTech Connect (OSTI)

The objective of this project is to gain a fundamental understanding of the oxygen-reduction mechanism on mixed conducting cathode materials by means of quantum-chemical calculations coupled with direct experimental measurements, such as vibrational spectroscopy. We have made progress in the elucidation of the mechanisms of oxygen reduction of perovkite-type cathode materials for SOFCs using these quantum chemical calculations. We established computational framework for predicting properties such as oxygen diffusivity and reaction rate constants for adsorption, incorporation, and TPB reactions, and formulated predictions for LSM- and LSC-based cathode materials. We have also further developed Raman spectroscopy as well as SERS as a characterization tool for SOFC cathode materials. Raman spectroscopy was used to detect chemical changes in the cathode from operation conditions, and SERS was used to probe for pertinent adsorbed species in oxygen reduction. However, much work on the subject of unraveling oxygen reduction for SOFC cathodes remains to be done.

Kevin Blinn; Yongman Choi; Meilin Liu

2009-08-11T23:59:59.000Z

57

Half-life of {sup 151}Sm remeasured  

SciTech Connect (OSTI)

The half-life of {sup 151}Sm was redetermined and compared with literature values. A {sup 151}Sm{sub 2}O{sub 3} sample was produced by exposing {sup 150}Sm{sub 2}O{sub 3} to the high neutron flux of the heavy water research reactor at the China Institute of Atomic Energy (CIAE). The number of atoms and the activity of {sup 151}Sm in the sample were measured by thermal ionization mass spectrometry (TIMS) and liquid scintillation counting (LSC), respectively. The half-life of {sup 151}Sm determined in this work is 96.6 yr, with a standard uncertainty of 2.4 yr based on a quadratic summation of the uncertainty components from the measurements of the number of atoms and the activity of {sup 151}Sm.

He Ming; Shen Hongtao; Shi Guozhu; Yin Xinyi; Tian Weizhi; Jiang Shan [Department of Nuclear Physics, China Institute of Atomic Energy, Post Office Box 275-50, Beijing 102413 (China)

2009-12-15T23:59:59.000Z

58

The NEXT experiment: A high pressure xenon gas TPC for neutrinoless double beta decay searches  

E-Print Network [OSTI]

Neutrinoless double beta decay is a hypothetical, very slow nuclear transition in which two neutrons undergo beta decay simultaneously and without the emission of neutrinos. The importance of this process goes beyond its intrinsic interest: an unambiguous observation would establish a Majorana nature for the neutrino and prove the violation of lepton number. NEXT is a new experiment to search for neutrinoless double beta decay using a radiopure high-pressure xenon gas TPC, filled with 100 kg of Xe enriched in Xe-136. NEXT will be the first large high-pressure gas TPC to use electroluminescence readout with SOFT (Separated, Optimized FuncTions) technology. The design consists in asymmetric TPC, with photomultipliers behind a transparent cathode and position-sensitive light pixels behind the anode. The experiment is approved to start data taking at the Laboratorio Subterr\\'aneo de Canfranc (LSC), Spain, in 2014.

D. Lorca; J. Martn-Albo; F. Monrabal; for the NEXT Collaboration

2012-10-15T23:59:59.000Z

59

Refined coconut oil as a source of dietary fat in a milk replacer for dairy calves  

E-Print Network [OSTI]

eesesae. ga gessac yesco che 4ieoeyery et escQdoasss, chs 41ssesssy sa4 sse ?4 ecohiliss4 viceala espplsssocb ~ Chs Leeseesso ess ot 4rls4 aLLb pss4sscs is oilb rsplassrr trsreoiee hae ssoccibscs4 cs chs ~Lep- osec ot Lapsoosa ss4 sttisissc er...LLh seplasee tssaslas (to) Chs sss4 terr lsc ss ~ elsCrsSMC lo ICLLb ssplssete tos osLToo ses cesecsiss4 as socle es cbs i4sa st teoaslociaw ~ spscbscia Fecfes Norr gssag saL~. os4-Liver eiL ~ Leraheblp cbs- ticac siL sss4 cs replace Che 4SC St Shale allb...

Barsales, Petronilo Bringuel

2012-06-07T23:59:59.000Z

60

STAG UK Newsletter Issue 3  

E-Print Network [OSTI]

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61

Synchrotron Investigations of SOFC Cathode Degradation  

SciTech Connect (OSTI)

The atomic variations occurring in cathode/electrolyte interface regions of La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3-?} (LSCF) cathodes and other SOFC related materials have been investigated and characterized using soft X-ray Absorption Spectroscopy (XAS) and diffuse soft X-ray Resonant Scattering (XRS). X-ray Absorption Spectroscopy in the soft X-ray region (soft XAS) is shown to be a sensitive technique to quantify the disruption that occurs and can be used to suggest a concrete mechanism for the degradation. For LSC, LSF, and LSCF films, a significant degradation mechanism is shown to be Sr out-diffusion. By using the XAS spectra of hexavalent Cr in SrCrO4 and trivalent Cr in Cr2O3, the driving factor for Sr segregation was identified to be the oxygen vacancy concentration at the anode and cathode side of of symmetric LSCF/GDC/LSCF heterostructures. This is direct evidence of vacancy induced cation diffusion and is shown to be a significant indicator of cathode/electrolyte interfacial degradation. X-ray absorption spectroscopy is used to identify the occupation of the A-sites and B-sites for LSC, LSF, and LSCF cathodes doped with other transition metals, including doping induced migration of Sr to the anti-site for Sr, a significant cathode degradation indicator. By using spatially resolved valence mapping of Co, a complete picture of the surface electrochemistry can be determined. This is especially important in identifying degradation phenomena where the degradation is spatially localized to the extremities of the electrochemistry and not the average. For samples that have electrochemical parameters that are measured to be spatially uniform, the Co valence modifications were correlated to the effects of current density, overpotential, and humidity.

Idzerda, Yves

2013-09-30T23:59:59.000Z

62

The use of low-level liquid scintillation spectrometry for rapid measurement and decision making  

SciTech Connect (OSTI)

Liquid scintillation spectrometry (LSC) has proved over the last fifteen years to be an excellent tool for low-level counting of beta- and alpha-particle emitters. Using low-level instruments the determination of, for instance {sup 90}Sr, could be considerably simplified in the laboratory, saving time and also money for chemicals and manpower. Furthermore, low-level instruments have been successfully used for measurements when fast analysis was required. The four instruments (Quantulus, Wallac Oy), that the author uses, have not only very low background, which cuts measurement time considerably; but from the pulse- height spectra much information about the nature of the radionuclides present and the absence of specific radionuclides can be extracted. From the absence of high-energy beta-particle activity in the pulse-height spectra of precipitation in the first days after the Chernobyl accident the author could draw the conclusion, that practically no {sup 90}Y was present and therefore only small amounts of {sup 90}Sr, if any, could be expected in precipitation and later in food. This enabled them to make the decision not to waste time with a large number of {sup 90}Sr analyses. Large numbers of drinking water samples could be screened for contamination much more sensitively and faster than by gamma-ray spectrometry. More examples will be presented of cases where rapid information was needed; how contamination and nuclear installations can be easily checked and how LSC helped to cut down the time required, the manpower and the costs for radon measurements and environmental surveillance.

Schoenhofer, F. [Federal Inst. for Food Control and Research (Austria)

1998-12-31T23:59:59.000Z

63

Selective Extraction of Uranium from Liquid or Supercritical Carbon Dioxide  

SciTech Connect (OSTI)

Current liquid-liquid extraction processes used in recycling irradiated nuclear fuel rely on (1) strong nitric acid to dissolve uranium oxide fuel, and (2) the use of aliphatic hydrocarbons as a diluent in formulating the solvent used to extract uranium. The nitric acid dissolution process is not selective. It dissolves virtually the entire fuel meat which complicates the uranium extraction process. In addition, a solvent washing process is used to remove TBP degradation products, which adds complexity to the recycling plant and increases the overall plant footprint and cost. A liquid or supercritical carbon dioxide (l/sc -CO2) system was designed to mitigate these problems. Indeed, TBP nitric acid complexes are highly soluble in l/sc -CO2 and are capable of extracting uranium directly from UO2, UO3 and U3O8 powders. This eliminates the need for total acid dissolution of the irradiated fuel. Furthermore, since CO2 is easily recycled by evaporation at room temperature and pressure, it eliminates the complex solvent washing process. In this report, we demonstrate: (1) A reprocessing scheme starting with the selective extraction of uranium from solid uranium oxides into a TBP-HNO3 loaded Sc-CO2 phase, (2) Back extraction of uranium into an aqueous phase, and (3) Conversion of recovered purified uranium into uranium oxide. The purified uranium product from step 3 can be disposed of as low level waste, or mixed with enriched uranium for use in a reactor for another fuel cycle. After an introduction on the concept and properties of supercritical fluids, we first report the characterization of the different oxides used for this project. Our extraction system and our online monitoring capability using UV-Vis absorbance spectroscopy directly in sc-CO2 is then presented. Next, the uranium extraction efficiencies and kinetics is demonstrated for different oxides and under different physical and chemical conditions: l/sc -CO2 pressure and temperature, TBP/HNO3 complex used, reductant or complexant used for selectivity, and ionic liquids used as supportive media. To complete the extraction and recovery cycle, we then demonstrate uranium back extraction from the TBP loaded sc-CO2 phase into an aqueous phase and the characterization of the uranium complex formed at the end of this process. Another aspect of this project was to limit proliferation risks by either co-extracting uranium and plutonium, or by leaving plutonium behind by selectively extracting uranium. We report that the former is easily achieved, since plutonium is in the tetravalent or hexavalent oxidation state in the oxidizing environment created by the TBP-nitric acid complex, and is therefore co-extracted. The latter is more challenging, as a reductant or complexant to plutonium has to be used to selectively extract uranium. After undertaking experiments on different reducing or complexing systems (e.g., AcetoHydroxamic Acid (AHA), Fe(II), ascorbic acid), oxalic acid was chosen as it can complex tetravalent actinides (Pu, Np, Th) in the aqueous phase while allowing the extraction of hexavalent uranium in the sc-CO2 phase. Finally, we show results using an alternative media to commonly used aqueous phases: ionic liquids. We show the dissolution of uranium in ionic liquids and its extraction using sc-CO2 with and without the presence of AHA. The possible separation of trivalent actinides from uranium is also demonstrated in ionic liquids using neodymium as a surrogate and diglycolamides as the extractant.

Farawila, Anne F.; O'Hara, Matthew J.; Wai, Chien M.; Taylor, Harry Z.; Liao, Yu-Jung

2012-07-31T23:59:59.000Z

64

Testing of a coal-fired diesel power plant  

SciTech Connect (OSTI)

The POC coal-fired power plant consists of a Cooper-Bessemer LSC-6 engine (15.5 inch bore, 22 inch stroke) rated at 400 rev/min and 208 psi bmep producing approximately 1.8 MW of power. The power plant is fueled with 'engine grade' coal slurry which has been physically cleaned to an ash level of approximately 1.5 to 2% (dry basis) and has a mean particle size of approximately 12 micron. CWS is injected directly into the combustion chamber through a fuel injector (one per cylinder) which was designed and developed to be compatible with the fuel. Each injector is fitted with a 19 orifice nozzle tip made with sapphire inserts in each orifice. The combustion chambers are fitted with twin diesel pilot injectors which provide a positive ignition source and substantially shorten the ignition delay period of the CWS fuel. Durable coatings (typically tungsten carbide) are used for the piston rings and cylinder liners to reduce wear rates. The emission control system consists of SCR for NO[sub x] control, sodium sorbent injection for SO[sub x] control, and a cyclone plus baghouse for particulate capture. The cyclone is installed upstream of the engine turbocharger which helps protect the turbine blades.

Wilson, R.P.; Balles, E.N.; Benedek, K.R.; Benson, C.E. (Little (Arthur D.), Inc., Cambridge, MA (United States)); Rao, K.; Schaub, F. (Cooper-Bessemer, Mount Vernon, OH (United States)); Kimberley, J. (AMBAC, West Springfield, MA (United States)); Itse, D. (PSI Technology Co., Andover, MA (United States))

1993-01-01T23:59:59.000Z

65

Testing of a coal-fired diesel power plant  

SciTech Connect (OSTI)

The POC coal-fired power plant consists of a Cooper-Bessemer LSC-6 engine (15.5 inch bore, 22 inch stroke) rated at 400 rev/min and 208 psi bmep producing approximately 1.8 MW of power. The power plant is fueled with `engine grade` coal slurry which has been physically cleaned to an ash level of approximately 1.5 to 2% (dry basis) and has a mean particle size of approximately 12 micron. CWS is injected directly into the combustion chamber through a fuel injector (one per cylinder) which was designed and developed to be compatible with the fuel. Each injector is fitted with a 19 orifice nozzle tip made with sapphire inserts in each orifice. The combustion chambers are fitted with twin diesel pilot injectors which provide a positive ignition source and substantially shorten the ignition delay period of the CWS fuel. Durable coatings (typically tungsten carbide) are used for the piston rings and cylinder liners to reduce wear rates. The emission control system consists of SCR for NO{sub x} control, sodium sorbent injection for SO{sub x} control, and a cyclone plus baghouse for particulate capture. The cyclone is installed upstream of the engine turbocharger which helps protect the turbine blades.

Wilson, R.P.; Balles, E.N.; Benedek, K.R.; Benson, C.E. [Little (Arthur D.), Inc., Cambridge, MA (United States); Rao, K.; Schaub, F. [Cooper-Bessemer, Mount Vernon, OH (United States); Kimberley, J. [AMBAC, West Springfield, MA (United States); Itse, D. [PSI Technology Co., Andover, MA (United States)

1993-01-01T23:59:59.000Z

66

Neutron flux estimations based on niobium impurities in reactor pressure vessel steel  

SciTech Connect (OSTI)

The use of (ppm level) niobium impurities in reactor pressure vessel (RPV) steel for neutron flux estimations based on the reaction {sup 93}Nb (n,n{prime}) {sup 93m}Nb has been reported previously. The method has now been further investigated and refined. Small niobium fractions in RPV steel ({approx} ppm) and plating ({approx} 1%) materials have been separated by ion exchange chromatography in one to three steps. The measured Nb fractions in samples from some four pressure vessel (RPV) base materials were 1 to 3 ppm. The purification of tens of milligrams of RPV material provides sufficient amounts of niobium for mass determination with a highly sensitive (10{sup {minus}5} ppm) Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The {sup 93m}Nb and small remaining {sup 54}Mn activities were measured with a Calibrated Liquid Scintillation Counter (LSC) based on dual label technique and almost 100% efficiency to {sup 93m}Nb. One purification is needed for plating materials ({approx}1% Nb) and two purifications of about one gram of steel with Nb impurities in order to resolve the needed activities ({approx}10 Bq {sup 93m}Nb/{mu}g Nb). The achieved accuracy of the measured specific {sup 93m}Nb activities was about {+-} 3% (1{sigma}) in irradiated RPV plating materials and about {+-} 4% for Nb ppm impurities.

Baers, L.B.; Hasanen, E.K. [Technical Research Centre of Finland, Espoo (Finland). Reactor Lab.

1994-12-31T23:59:59.000Z

67

Accelerated Analyte Uptake on Single Beads in Microliter-scale Batch Separations using Acoustic Streaming: Plutonium Uptake by Anion Exchange for Analysis by Mass Spectrometry  

SciTech Connect (OSTI)

The use of acoustic streaming as a non-contact mixing platform to accelerate mass transport-limited diffusion processes in small volume heterogeneous reactions has been investigated. Single bead anion exchange of plutonium at nanomolar and sub-picomolar concentrations in 20 microliter liquid volumes was used to demonstrate the effect of acoustic mixing. Pu uptake rates on individual ~760 micrometer diameter AG 1x4 anion exchange resin beads were determined using acoustic mixing and compared with Pu uptake rates achieved by static diffusion alone. An 82 MHz surface acoustic wave (SAW) device was placed in contact with the underside of a 384-well microplate containing flat-bottomed semiconical wells. Acoustic energy was coupled into the solution in the well, inducing acoustic streaming. Pu uptake rates were determined by the plutonium remaining in solution after specific elapsed time intervals, using liquid scintillation counting (LSC) for nanomolar concentrations and thermal ionization mass spectrometry (TIMS) analysis for the sub-picomolar concentration experiments. It was found that this small batch uptake reaction could be accelerated by a factor of about five-fold or more, depending on the acoustic power applied.

Paxton, Walter F.; O'Hara, Matthew J.; Peper, Shane M.; Petersen, Steven L.; Grate, Jay W.

2008-06-01T23:59:59.000Z

68

Accelerator waste - A new challenge for radio-analytics  

SciTech Connect (OSTI)

The Paul Scherrer Institute (PSI) at Villigen (Switzerland) operates the most powerful accelerator facility in Europe. Due to the increasing quantities of accelerator waste with almost unknown radionuclide inventory, the development of new radio-analytical methods is an urgent task. Besides the characterization by {gamma}-measurements and dose rate determinations, also the investigation of long-lived radionuclides, being probably essential for a final disposal, is required from Swiss authorities. Chemical separation is necessary for the determination of the majority of these isotopes. As a representative example for such studies, the analytics of a beam dump assembly is introduced. Samples were taken from the target E beam dump station from the 590 MeV proton accelerator facility. The content of several radionuclides with half-lives between 2 and 10{sup 7} years was determined by {gamma}-spectrometry and, after chemical separation, by Liquid Scintillation Counting (LSC) as well as Accelerator Mass Spectrometry (AMS). The results are compared with theoretical predictions. Long-term object of these studies is the elaboration of nuclide vectors, which allow the estimation of nuclide inventories by simple calculations. (authors)

Schumann, Dorothea; Neuhausen, Joer; Wohlmuther, Michaelg [Paul Scherrer Institute 5232, Villigen PSI (Switzerland)

2007-07-01T23:59:59.000Z

69

Mitigation Plans for the Microbunching-Instability-Related COTR at ASTA/FNAL  

SciTech Connect (OSTI)

At the Advanced Superconducting Test Accelerator (ASTA) now under construction at Fermilab, we anticipate the appearance of the microbunching instability related to the longitudinal space charge (LSC) impedances. With a photoinjector source and up to two chicane compressors planned, the conditions should result in the shift of some microbunched features into the visible light regime. The presence of longitudinal microstructures (microbunching) in the electron beam or the leading edge spikes can result in strong, spatially localized coherent enhancements of optical transition radiation (COTR) that mask the actual beam profile. Several efforts on mitigation of the effects in the diagnostics task have been identified. At ASTA we have designed the beam profiling stations to have mitigation features based on spectral filtering, scintillator choice, and the timing of the trigger to the digital camera's CCD chip. Since the COTR is more intense in the NIR than UV we have selectable bandpass filters centered at 420 nm which also overlap the spectral emissions of the LYSO:Ce scintillators. By delaying the CCD trigger timing of the integration window by 40-50 ns, we can reject the prompt OTR signal and integrate on the delayed scintillator light predominately. This combination of options should allow mitigation of COTR enhancements of order 100-1000 in the distribution.

Lumpkin, A. H.; Johnson, A. M.

2013-05-01T23:59:59.000Z

70

Next Generation Print-based Manufacturing for Photovoltaics and Solid State Lighting  

SciTech Connect (OSTI)

For the grand challenge of reducing our energy and carbon footprint, the development of renewable energy and energy efficient technologies offer a potential solution. Energy technologies can reduce our dependence on foreign oil as well as the energy consumed by the petroleum industry, the leading consumer of energy by a U.S. industry sector. Nonetheless, the manufacturing processes utilized to manufacture equipment for alternative energy technologies often involve energy-intensive processes. This undermines some of the advantages to moving to 'green' technologies in the first place. Our answer to the Industrial Technology Program's (ITP) Grand Challenge FOA was to develop a transformational low cost manufacturing process for plastic-based photovoltaics that will lower by over 50% both energy consumption and greenhouse emissions and offer a return-of-investment of over 20%. We demonstrated a Luminescent Solar Concentrator fabricated on a plastic acrylic substrate (i.e. no glass) that increases the power output of the PV cell by 2.2x with a 2% power efficiency as well as an LSC with a 7% power efficiency that increased the power output from the PV cells by 35%. S large area 20-inch x 60-inch building-integrated photovoltaic window was fabricated using contract manufacturing with a 4% power efficiency which improved the power output of the PV cell by over 50%. In addition, accelerated lifetimes of the luminescent material demonstrate lifetimes of 20-years.

Sue A. Carter

2012-09-07T23:59:59.000Z

71

Laser Electron Gamma Source: Biennial progress report, June 1996  

SciTech Connect (OSTI)

The LEGS facility provides intense, polarized, monochromatic {gamma}-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the National Synchrotron Light Source at Brookhaven national Laboratory. Since 1990, experiments have concentrated on single polarization observables (polarized beams on unpolarized targets) in nuclear reactions involving the {Delta} resonance. Highlights of the last two years are given. An updated status of LEGS, and recent publications, is available on the WWW via http://WWW.LEGS.BNL.GOV/{approximately}LEGS/. In 1997 a new phase of operations will begin, focusing on double-polarization measurements with circularly polarized photon beams and longitudinally polarized nucleon targets. This work requires the development of (i) a new frozen-spin hydrogen-deuteride target that provides high polarizations for both nuclear species, and (ii) a new large acceptance detector array for measuring total reaction cross sections in both neutral and charged-particle channels. Progress on these instrumentation developments is an ongoing effort of the LEGS Spin Collaboration (LSC) and is discussed in the last section of this report.

Sandorfi, A.M. [ed.

1996-09-01T23:59:59.000Z

72

Leak before break evaluation for main steam piping system made of SA106 Gr.C  

SciTech Connect (OSTI)

The basis of the leak before break (LBB) concept is to demonstrate that piping will leak significantly before a double ended guillotine break (DEGB) occurs. This is demonstrated by quantifying and evaluating the leak process and prescribing safe shutdown of the plant on the basis of the monitored leak rate. The application of LBB for power plant design has reduced plant cost while improving plant integrity. Several evaluations employing LBB analysis on system piping based on DEGB design have been completed. However, the application of LBB on main steam (MS) piping, which is LBB applicable piping, has not been performed due to several uncertainties associated with occurrence of steam hammer and dynamic strain aging (DSA). The objective of this paper is to demonstrate the applicability of the LBB design concept to main steam lines manufactured with SA106 Gr.C carbon steel. Based on the material properties, including fracture toughness and tensile properties obtained from the comprehensive material tests for base and weld metals, a parametric study was performed as described in this paper. The PICEP code was used to determine leak size crack (LSC) and the FLET code was used to perform the stability assessment of MS piping. The effects of material properties obtained from tests were evaluated to determine the LBB applicability for the MS piping. It can be shown from this parametric study that the MS piping has a high possibility of design using LBB analysis.

Yang, Kyoung Mo; Jee, Kye Kwang; Pyo, Chang Ryul; Ra, In Sik [Korea Power Engineering Company, Seoul (Korea, Republic of)

1997-04-01T23:59:59.000Z

73

Design and characterization of the SiPM tracking system of the NEXT-100 demonstrator  

E-Print Network [OSTI]

NEXT-100 is a new experiment to search for neutrinoless double-beta decay of the Xe-136 isotope using a TPC filled with a 100 kg of high-pressure gaseous xenon with 90% isotopic enrichment. The experiment will take place at the Laboratorio Subterr\\'aneo de Canfranc (LSC), Spain. NEXT-100 uses electroluminescence (EL) technology for high energy resolution measurements. The gaseous xenon in the TPC allows additionally to record the tracks of the two beta particles, expected to have up to 30 cm length at 10 bar pressure. A full 3D sampling of the space points along the event tracks, using an optical readout system of the EL light, enables the identification of the double-beta events by means of a pattern recognition algorithm. In this paper, the SiPM-based tracking concept of NEXT-100 and its implementation in the demonstrator prototype NEXT-DEMO are presented. The characterization of the SiPM system and its readout electronics are described and shown to meet the experiment's requirements for the optimal recordi...

lvarez, V; Borges, F I G M; Crcel, S; Carmona, J M; Castel, J; Catal, J M; Cebrin, S; Cervera, A; Chan, D; Conde, C A N; Dafni, T; Dias, T H V T; Daz, J; Egorov, M; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Ferrer-Ribas, E; Freitas, E D C; Garcia, A N C; Gehman, V M; Gil, A; Giomataris, I; Goldschmidt, A; Gmez, H; Gmez-Cadenas, J J; Gonzlez, K; Gonzlez-Daz, D; Gutirrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Herrero, V; Iguaz, F J; Irastorza, I G; Kalinnikov, V; Kiang, D; Labarga, L; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzn, G; Mar, A; Martn-Albo, J; Martnez, A; Miller, T; Moiseenko, A; Monrabal, F; Monteiro, C M B; Monz, J M; Mora, F J; Moutinho, L M; Vidal, J Muoz; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; Palma, R; Prez, J; Aparicio, J L Prez; Renner, J; Ripoll, L; Rodrguez, A; Rodrguez, J; Santos, F P; Santos, J M F dos; Segui, L; Serra, L; Shuman, D; Sofka, C; Sorel, M; Toledo, J F; Toms, A; Torrent, J; Tsamalaidze, Z; Vzquez, D; Velicheva, E; Veloso, J F C A; Villar, J A; Webb, R C; Weber, T; White, J; Yahlali, N

2012-01-01T23:59:59.000Z

74

Chancellor Water Colloids: Characterization and Radionuclide Association  

SciTech Connect (OSTI)

Concluding remarks about this paper are: (1) Gravitational settling, zeta potential, and ultrafiltration data indicate the existence of a colloidal phase of both the alpha and beta emitters in the Chancellor water; (2) The low activity combined with high dispersion homogeneity of the Chancellor water indicate that both alpha and beta emitters are not intrinsic colloids; (3) Radionuclides in the Chancellor water, particularly Pu, coexist as dissolved aqueous and sorbed phases - in other words the radionuclides are partitioned between the aqueous phase and the colloidal phase; (4) The presence of Pu as a dissolved species in the aqueous phase, suggests the possibility of Pu in the (V) oxidation state - this conclusion is supported by the similarity of the k{sub d} value of Pu determined in the current study to that determined for Pu(V) sorbed onto smectite colloids, and the similar electrokinetic behavior of the Chancellor water colloids to smectite colloids; (5) About 50% of the Pu(V) is in the aqueous phase and 50% is sorbed on colloids (mass concentration of colloids in the Chancellor water is 0.12 g/L); (6) The k{sub d} of the Pu and the beta emitters (fission products) between aqueous and colloidal phases in the Chancellor water is {approx}8.0 x 10{sup 3} mL/g using two different activity measurement techniques (LSC and alpha spectroscopy); (7) The gravitational settling and size distributions of the association colloids indicate that the properties (at least the physical ones) of the colloids to which the alpha emitters are associated with seem to be different that the properties of the colloids to which the beta emitters are associated with - the beta emitters are associated with very small particles ({approx}50 - 120 nm), while the alpha emitters are associated with relatively larger particles; and (8) The Chancellor water colloids are extremely stable under the natural pH and ionic strength conditions, indicating high potential for transport in the subsurface.

Abdel-Fattah, Amr I. [Los Alamos National Laboratory

2012-06-18T23:59:59.000Z

75

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over the pressure range studied. From the stoichiometry a lower limit of 2.6 corresponding to the reduction of all Fe{sup 4+} to Fe{sup 3+} and no reduction of Cr{sup 3+} is expected.

S. Bandopadhyay; N. Nagabhushana

2003-08-07T23:59:59.000Z

76

Upper and lower limits on the Crab pulsar's astrophysical parameters set from gravitational wave observations by LIGO: braking index and energy considerations  

E-Print Network [OSTI]

The Laser Interferometer Gravitational Observatory (LIGO) has recently reached the end of its fifth science run (S5), having collected more than a year worth of data. Analysis of the data is still ongoing but a positive detection of gravitational waves, while possible, is not realistically expected for most likely sources. This is particularly true for what concerns gravitational waves from known pulsars. In fact, even under the most optimistic (and not very realistic) assumption that all the pulsar's observed spin-down is due to gravitational waves, the gravitational wave strain at earth from all the known isolated pulsars (with the only notable exception of the Crab pulsar) would not be strong enough to be detectable by existing detectors. By August 2006, LIGO had produced enough data for a coherent integration capable to extract signal from noise that was weaker than the one expected from the Crab pulsar's spin-down limit. No signal was detected, but beating the spin-down limit is a considerable achievement for the LIGO Scientific Collaboration (LSC). It is customary to translate the upper limit on strain from a pulsar into a more astrophysically significant upper limit on ellipticity. Once the spin-down limit has been beaten, it is possible to release the constraint that all the spin-down is due to gravitational wave emission. A more complete model with diverse braking mechanisms can be used to set limits on several astrophysical parameters of the pulsar. This paper shows possible values of such parameters for the Crab pulsar given the current limit on gravitational waves from this neutron star.

Giovanni Santostasi

2008-07-16T23:59:59.000Z

77

Determining the ecological viability of constructed wetlands for the treatment of oil sands wastewater  

SciTech Connect (OSTI)

To determine the conditions for optimal degradation of naphthenic acids (C{sub n}H{sub 2n+z}O{sub 2}), the most toxic component of oil sands wastewater, the authors have monitored the mineralization of 2 representative naphthenic acids (NA), U-{sup 14}C-palmitic acid (linear, Z = 0) and 8-{sup 14}C-decahydro-2-naphthoic acid (bicyclic, Z = {minus}4) under varying conditions of temperature, phosphate and oxygen. The radiolabeled NA was added to biometer flasks containing wastewater {+-} amendments and evolved {sup 14}C-CO{sub 2} was trapped in a side arm and counted by LSC. The results indicate that low temperature (5 C) and anaerobiasis greatly inhibited NA degradation over the four week incubation period. Addition of phosphate (as buffered KP{sub i}) significantly increased {sup 14}C-CO{sub 2} production for both Z = 0 and Z = {minus}4 compounds; however, the subsequent high microbial growth rates also decreased PO{sub 2} which limited NA mineralization. Effluent toxicity was monitored at week 0 and week 4 using Microtox and fathead minnow tests. Although there was increased survival of fathead minnows in the phosphate-amended effluent, the IC{sub 20} values of the Microtox assay showed no improvement in either the phosphate-treated or untreated effluents. These results show that naphthenic acid analogues are readily degraded by indigenous microorganisms in oil sands wastewater and that phosphate addition accelerated the mineralization of these compounds if PO{sub 2} remained high.

Lai, J.; Kiehlmann, E.; Pinto, L.; Bendell-Young, L.; Moore, M. [Simon Fraser Univ., Burnaby, British Columbia (Canada); Nix, P. [EVS Environment Consultants, North Vancouver, British Columbia (Canada)

1995-12-31T23:59:59.000Z

78

Critical Causes of Degradation in Integrated Laboratory Scale Cells during High Temperature Electrolysis  

SciTech Connect (OSTI)

An ongoing project at Idaho National Laboratory involves generating hydrogen from steam using solid oxide electrolysis cells (SOEC). This report describes background information about SOECs, the Integrated Laboratory Scale (ILS) testing of solid-oxide electrolysis stacks, ILS performance degradation, and post-test examination of SOECs by various researchers. The ILS test was a 720- cell, three-module test comprised of 12 stacks of 60 cells each. A peak H2 production rate of 5.7 Nm3/hr was achieved. Initially, the module area-specific resistance ranged from 1.25 Ocm2 to just over 2 Ocm2. Total H2 production rate decreased from 5.7 Nm3/hr to a steady state value of 0.7 Nm3/hr. The decrease was primarily due to cell degradation. Post test examination by Ceramatec showed that the hydrogen electrode appeared to be in good condition. The oxygen evolution electrode does show delamination in operation and an apparent foreign layer deposited at the electrolyte interface. Post test examination by Argonne National Laboratory showed that the O2-electrode delaminated from the electrolyte near the edge. One possible reason for this delamination is excessive pressure buildup with high O2 flow in the over-sintered region. According to post test examination at the Massachusetts Institute of Technology, the electrochemical reactions have been recognized as one of the prevalent causes of their degradation. Specifically, two important degradation mechanisms were examined: (1) transport of Crcontaining species from steel interconnects into the oxygen electrode and LSC bond layers in SOECs, and (2) cation segregation and phase separation in the bond layer. INL conducted a workshop October 27, 2008 to discuss possible causes of degradation in a SOEC stack. Generally, it was agreed that the following are major degradation issues relating to SOECs: Delamination of the O2-electrode and bond layer on the steam/O2-electrode side Contaminants (Ni, Cr, Si, etc.) on reaction sites (triple phase boundary) Loss of electrical/ionic conductivity of electrolyte.

M.S. Sohal; J.E. O'Brien; C.M. Stoots; J. J. Hartvigsen; D. Larsen; S. Elangovan; J.S. Herring; J.D. Carter; V.I. Sharma; B. Yildiz

2009-05-01T23:59:59.000Z

79

Material Sample Collection with Tritium and Gamma Analyses at the University of Illinois's Nuclear Research Laboratory TRIGA Nuclear Research Reactor  

SciTech Connect (OSTI)

The University of Illinois in Champaign-Urbana has an Advanced TRIGA reactor facility which was built in 1960 and operated until August 1998. The facility was shutdown for a variety of reasons, primarily due to a lack of usage by the host institution. In 1998 the reactor went into SAFSTOR and finally shipped its fuel in 2004. At the present time a site characterization and decommissioning plan are in process and hope to be submitted to the NRC in early 2006. The facility had to be fully characterized and part of this characterization involved the collection and analysis of samples. This included various solid media such as, concrete, graphite, metals, and sub-slab surface soils for immediate analysis of Activation and Tritium contamination well below the easily measured surfaces. This detailed facility investigation provided a case to eliminate historical unknowns, increasing the confidence for the segregation and packaging of high specific activity Low Level Radwaste (LLRW), from which a strategy of 'surgical-demolition' and segregation could be derived thus maximizing the volumes of 'clean material'. Performing quantitative volumetric concrete or metal radio-analyses safer and faster (without lab intervention) was a key objective of this dynamic characterization approach. Currently, concrete core bores are shipped to certified laboratories where the concrete residue is run through a battery of tests to determine the contaminants. The existing core boring operation volatilises or washes out some of the contaminants (like tritium) and oftentimes cross-contaminates the are a around the core bore site. The volatilization of the contaminants can lead to airborne problems in the immediate vicinity of the core bore. Cross-contamination can increase the contamination area and thereby increase the amount of waste generated that needs to be treated and stabilized before disposal. The goal was to avoid those field activities that could cause this type of release. Therefore, TRUPRO{sup R}, a sampling and profiling tool in conjunction with radiometric instrumentation was utilized to produce contamination profiles through the material being studied. All samples (except metals) on-site were analyzed within 10 minutes for tritium using a calibrated portable liquid scintillation counter (LSC) and analyzed for gamma activation products using a calibrated ISOCS. Improved sample collection with near real time analysis along with more historical hazard analysis enhanced significantly over the baseline coring approach the understanding of the depth distribution of contaminants. The water used in traditional coring can result in a radioactive liquid waste that needs to be dealt with. This would have been an issue at University of Illinois. Considerable time, risk reduction and money are saved using this profiling approach. (authors)

Charters, G.; Aggarwal, S. [New Millennium Nuclear Technologies, 575 Union Blvd, Suite 102, Lakewood, CO 80228 (United States)

2006-07-01T23:59:59.000Z

80

Quantum Dynamical Behaviour in Complex Systems - A Semiclassical Approach  

SciTech Connect (OSTI)

One of the biggest challenges in Chemical Dynamics is describing the behavior of complex systems accurately. Classical MD simulations have evolved to a point where calculations involving thousands of atoms are routinely carried out. Capturing coherence, tunneling and other such quantum effects for these systems, however, has proven considerably harder. Semiclassical methods such as the Initial Value Representation (SC-IVR) provide a practical way to include quantum effects while still utilizing only classical trajectory information. For smaller systems, this method has been proven to be most effective, encouraging the hope that it can be extended to deal with a large number of degrees of freedom. Several variations upon the original idea of the SCIVR have been developed to help make these larger calculations more tractable; these range from the simplest, classical limit form, the Linearized IVR (LSC-IVR) to the quantum limit form, the Exact Forward-Backward version (EFB-IVR). In this thesis a method to tune between these limits is described which allows us to choose exactly which degrees of freedom we wish to treat in a more quantum mechanical fashion and to what extent. This formulation is called the Tuning IVR (TIVR). We further describe methodology being developed to evaluate the prefactor term that appears in the IVR formalism. The regular prefactor is composed of the Monodromy matrices (jacobians of the transformation from initial to finial coordinates and momenta) which are time evolved using the Hessian. Standard MD simulations require the potential surfaces and their gradients, but very rarely is there any information on the second derivative. We would like to be able to carry out the SC-IVR calculation without this information too. With this in mind a finite difference scheme to obtain the Hessian on-the-fly is proposed. Wealso apply the IVR formalism to a few problems of current interest. A method to obtain energy eigenvalues accurately for complex systems is described. We proposed the use of a semiclassical correction term to a preliminary quantum calculation using, for instance, a variational approach. This allows us to increase the accuracy significantly. Modeling Nonadiabatic dynamics has always been a challenge to classical simulations because the multi-state nature of the dynamics cannot be described accurately by the time evolution on a single average surface, as is the classical approach. We show that using the Meyer-Miller-Stock-Thoss (MMST) representation of the exact vibronic Hamiltonian in combination with the IVR allows us to accurately describe dynamics where the non Born-Oppenheimer regime. One final problem that we address is that of extending this method to the long time regime. We propose the use of a time independent sampling function in the Monte Carlo integration over the phase space of initial trajectory conditions. This allows us to better choose the regions of importance at the various points in time; by using more trajectories in the important regions, we show that the integration can be converged much easier. An algorithm based loosely on the methods of Diffusion Monte Carlo is developed that allows us to carry out this time dependent sampling in a most efficient manner.

Gliebe, Cheryn E; Ananth, Nandini

2008-05-22T23:59:59.000Z