Band Gap Energy of Chalcopyrite Thin Film Solar Cell Absorbers Determined by Soft X-Ray Emission and Absorption Spectroscopy (open access)

Band Gap Energy of Chalcopyrite Thin Film Solar Cell Absorbers Determined by Soft X-Ray Emission and Absorption Spectroscopy

The chemical and electronic structure of high efficiency chalcopyrite thin film solar cell absorbers significantly differs between the surface and the bulk. While it is widely accepted that the absorber surface exhibits a Cu-poor surface phase with increased band gap (Eg), a direct access to the crucial information of the depth-dependency of Eg is still missing. In this paper, we demonstrate that a combination of x-ray emission and absorption spectroscopy allows a determination of Eg in the surface-near bulk and thus complements the established surface- and bulk-sensitive techniques of Eg determination. As an example, we discuss the determination of Eg for a Cu(In,Ga)Se2 absorber [(1.52 +- 0.20) eV].
Date: May 11, 2008
Creator: Bar, M.; Weinhardt, L.; Pookpanratana, S.; Heske, C.; Nishiwaki, S.; Shafarman, W. et al.
Object Type: Article
System: The UNT Digital Library
Opportunities for Energy Efficiency and Automated Demand Response in Industrial Refrigerated Warehouses in California (open access)

Opportunities for Energy Efficiency and Automated Demand Response in Industrial Refrigerated Warehouses in California

This report summarizes the Lawrence Berkeley National Laboratory's research to date in characterizing energy efficiency and open automated demand response opportunities for industrial refrigerated warehouses in California. The report describes refrigerated warehouses characteristics, energy use and demand, and control systems. It also discusses energy efficiency and open automated demand response opportunities and provides analysis results from three demand response studies. In addition, several energy efficiency, load management, and demand response case studies are provided for refrigerated warehouses. This study shows that refrigerated warehouses can be excellent candidates for open automated demand response and that facilities which have implemented energy efficiency measures and have centralized control systems are well-suited to shift or shed electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. Control technologies installed for energy efficiency and load management purposes can often be adapted for open automated demand response (OpenADR) at little additional cost. These improved controls may prepare facilities to be more receptive to OpenADR due to both increased confidence in the opportunities for controlling energy cost/use and access to the real-time data.
Date: May 11, 2009
Creator: Lekov, Alex; Thompson, Lisa; McKane, Aimee; Rockoff, Alexandra & Piette, Mary Ann
Object Type: Report
System: The UNT Digital Library
Use of Quantitative Uncertainty Analysis to Support M&VDecisions in ESPCs (open access)

Use of Quantitative Uncertainty Analysis to Support M&VDecisions in ESPCs

Measurement and Verification (M&V) is a critical elementof an Energy Savings Performance Contract (ESPC) - without M&V, thereisno way to confirm that the projected savings in an ESPC are in factbeing realized. For any given energy conservation measure in an ESPC,there are usually several M&V choices, which will vary in terms ofmeasurement uncertainty, cost, and technical feasibility. Typically,M&V decisions are made almost solely based on engineering judgmentand experience, with little, if any, quantitative uncertainty analysis(QUA). This paper describes the results of a pilot project initiated bythe Department of Energy s Federal Energy Management Program to explorethe use of Monte-Carlo simulation to assess savings uncertainty andthereby augment the M&V decision-making process in ESPCs. The intentwas to use QUA selectively in combination with heuristic knowledge, inorder to obtain quantitative estimates of the savings uncertainty withoutthe burden of a comprehensive "bottoms-up" QUA. This approach was used toanalyze the savings uncertainty in an ESPC for a large federal agency.The QUA was seamlessly integrated into the ESPC development process andthe incremental effort was relatively small with user-friendly tools thatare commercially available. As the case study illustrates, in some casesthe QUA simply confirms intuitive or qualitative information, while inother cases, it provides insight that suggests revisiting …
Date: May 11, 2005
Creator: Mathew, Paul A.; Koehling, Erick & Kumar, Satish
Object Type: Article
System: The UNT Digital Library
Measurement of CP-Violating Asymmetries in B0 to D(*)+D- (open access)

Measurement of CP-Violating Asymmetries in B0 to D(*)+D-

None
Date: May 11, 2007
Creator: Chen, C
Object Type: Article
System: The UNT Digital Library
Carrier-Density-Dependent Lattice Stability in InSb (open access)

Carrier-Density-Dependent Lattice Stability in InSb

None
Date: May 11, 2007
Creator: Hillyard, P. B.; Gaffney, K. J.; Lindenberg, A. M.; Engemann, S.; Akre, R. A.; Arthur, J. et al.
Object Type: Report
System: The UNT Digital Library
Theoretical Studies of Complex Systems: Water, Pores and the hydrogen fuel systems. (open access)

Theoretical Studies of Complex Systems: Water, Pores and the hydrogen fuel systems.

A theory for the electroreduction/oxidation was formulated A new density formalism is discused with possible applications to pores in membranes
Date: May 11, 2007
Creator: Blum, Lesser
Object Type: Report
System: The UNT Digital Library
Development of a Compact Radiography Accelerator Using Dielectric Wall Accelerator Technology (open access)

Development of a Compact Radiography Accelerator Using Dielectric Wall Accelerator Technology

None
Date: May 11, 2005
Creator: Sampayan, S.; Caporaso, G.; Chen, Y.; Hawkins, S.; Holmes, C.; McCarrick, J. et al.
Object Type: Article
System: The UNT Digital Library
Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes (open access)

Search for D^0-\overline{D}^0 Mixing Using Doubly Flavor TaggedSemileptonic Decay Modes

None
Date: May 11, 2007
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Investigation of Leveling Equipment for High Precision Measurements (open access)

Investigation of Leveling Equipment for High Precision Measurements

None
Date: May 11, 2007
Creator: Gassner, G. L. & Ruland, R. E.
Object Type: Article
System: The UNT Digital Library
Supersymmetry in Particle Physics - An Elementary Introduction (open access)

Supersymmetry in Particle Physics - An Elementary Introduction

None
Date: May 11, 2007
Creator: Aitchison, I.J.R. & /Oxford U., Theor. Phys. /SLAC
Object Type: Report
System: The UNT Digital Library
An improved strategy to detect CO2 leakage for verification ofgeologic carbon sequestration (open access)

An improved strategy to detect CO2 leakage for verification ofgeologic carbon sequestration

To detect and quantify subtle surface CO2 leakage signals, we present a strategy that combines measurements of CO2 fluxes or concentrations in the near-surface environment with an algorithm that enhances temporally- and spatially-correlated leakage signals while suppressing random background noise. The algorithm consists of a filter that highlights spatial coherence in the leakage signal, and temporal stacking (averaging) that reduces noise from temporally uncorrelated background fluxes/concentrations. We assess the performance of our strategy using synthetic data sets in which the surface leakage signal is either specified directly or calculated using flow and transport simulations of leakage source geometries one might expect to be present at sequestration sites. We estimate the number of measurements required to detect a potential CO2 leakage signal of given magnitude and area. Results show that given a rigorous field-sampling program, subtle CO2 leakage may be detected using the algorithm; however, leakage of very limited spatial extent or exceedingly small magnitude may be difficult to detect with a reasonable set of monitoring resources.
Date: May 11, 2006
Creator: Lewicki, Jennifer L.; Hilley, George E. & Oldenburg, Curtis M.
Object Type: Article
System: The UNT Digital Library
Search for B0 to phi(K+pi-) Decays with Large K+pi- Invariant Mass (open access)

Search for B0 to phi(K+pi-) Decays with Large K+pi- Invariant Mass

None
Date: May 11, 2007
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
FINAL SCIENTIFIC REPORT - PROTON RADIOGRAPHY: CROSS SECTION MEASUREMENTS AND DETECTOR DEVELOPMENT (open access)

FINAL SCIENTIFIC REPORT - PROTON RADIOGRAPHY: CROSS SECTION MEASUREMENTS AND DETECTOR DEVELOPMENT

Proton radiography offers significant advantages over conventional X-ray radiography, including the capability of looking into thick, dense materials, better contrast for a wide range of materials, sensitivity to different materials of similar density, and better resolution because of the ability to focus beams. In order to achieve this capability it is crucial to understand the background due to neutrons and photons and to develop techniques to reduce it to tolerable levels. The physics goal of this project is to measure forward production of neutrons and photons produced by high-energy proton beams striking a variety of targets. This work is being carried out in conjunction with the Fermilab Experiment 907 (MIPP) collaboration including physicists from Lawrence Livermore Laboratory. Our group is responsible for the E907 forward neu-tron/photon calorimeters. These are the only detectors in the experiment that provide informa-tion on neutrons and photons. We are taking a leading role in obtaining and analyzing the for-ward production data and in developing an optimal detector for proton radiography. With the support of our Stewardship Science Academic Alliances grant, we were able to design, build, and commission the calorimeters on budget and ahead of schedule. E-907 officially started physics running at Fermilab in January …
Date: May 11, 2007
Creator: Longo, Michael J.; Gustafson, H. Richard.; Rajaram, Durga & Nigmanov, Turgun
Object Type: Report
System: The UNT Digital Library
Search for the Radiative Leptonic Decay B^{+} to gamma \ell^{+}\nu_{\ell} (open access)

Search for the Radiative Leptonic Decay B^{+} to gamma \ell^{+}\nu_{\ell}

None
Date: May 11, 2007
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
Object Type: Article
System: The UNT Digital Library
Review of Livermore-Led Neutron Capture Studies Using DANCE (open access)

Review of Livermore-Led Neutron Capture Studies Using DANCE

We have made neutron capture cross-section measurements using the white neutron source at the Los Alamos Science Center, the DANCE detector array (Detector for Advanced Neutron Capture Experiments) and targets important for basic science and stockpile stewardship. In this paper, we review results from (n,{gamma}) reactions on {sup 94,95}Mo, {sup 152,154,157,160,nat}Gd, {sup 151,153}Eu and {sup 242m}Am for neutron energies from < 1eV up to {approx} 20 keV. We measured details of the {gamma}-ray cascade following neutron capture, for comparison with results of statistical model simulations. We determined the neutron energy dependent (n,{gamma}) cross section and gained information about statistical decay properties, including the nuclear level density and the photon strength function. Because of the high granularity of the detector array, it is possible to look at gamma cascades with a specified number of transitions (a specific multiplicity). We simulated {gamma}-ray cascades using a combination of the DICEBOX/GEANT computer codes. In the case of the deformed nuclei, we found evidence of a scissors-mode resonance. For the Eu, we also determined the (n,{gamma}) cross sections. For the {sup 94,95}Mo, we focused on the spin and parity assignments of the resonances and the determination of the photon strength functions for the compound nuclei …
Date: May 11, 2007
Creator: Parker, W.; Sheets, S.; Agvaanluvsan, U.; Becker, J.; Becvar, F.; Bredeweg, T. et al.
Object Type: Article
System: The UNT Digital Library
Compact Neutron Generators for Medical Home Land Security andPlanetary Exploration (open access)

Compact Neutron Generators for Medical Home Land Security andPlanetary Exploration

The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented.
Date: May 11, 2005
Creator: Reijonen, J.
Object Type: Article
System: The UNT Digital Library
Waste Package Lifting Calculation (open access)

Waste Package Lifting Calculation

The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation.
Date: May 11, 2000
Creator: Marr, H.
Object Type: Report
System: The UNT Digital Library
LFR "Lead-Cooled Fast Reactor" (open access)

LFR "Lead-Cooled Fast Reactor"

The main purpose of this paper is to present the current status of development of the Lead-cooled Fast Reactor (LFR) in Generation IV (GEN IV), including the European contribution, to identify needed R&D and to present the corresponding GEN IV International Forum (GIF) R&D plan [1] to support the future development and deployment of lead-cooled fast reactors. The approach of the GIF plan is to consider the research priorities of each member country in proposing an integrated, coordinated R&D program to achieve common objectives, while avoiding duplication of effort. The integrated plan recognizes two principal technology tracks: (1) a small, transportable system of 10-100 MWe size that features a very long refuelling interval, and (2) a larger-sized system rated at about 600 MWe, intended for central station power generation. This paper provides some details of the important European contributions to the development of the LFR. Sixteen European organizations have, in fact, taken the initiative to present to the European Commission the proposal for a Specific Targeted Research and Training Project (STREP) devoted to the development of a European Lead-cooled System, known as the ELSY project; two additional organizations from the US and Korea have joined the project. Consequently, ELSY will …
Date: May 11, 2006
Creator: Cinotti, L.; Fazio, C.; Knebel, J.; Monti, S.; Abderrahim, H. A.; Smith, C. et al.
Object Type: Article
System: The UNT Digital Library
Water-Rock Interaction-11: Saratoga Springs, NY 11th International Symposium on Water Rock Interaction (open access)

Water-Rock Interaction-11: Saratoga Springs, NY 11th International Symposium on Water Rock Interaction

None
Date: May 11, 2007
Creator: Brantley, Susan, L.
Object Type: Report
System: The UNT Digital Library
Parallel Algebraic Multigrids for Structural mechanics (open access)

Parallel Algebraic Multigrids for Structural mechanics

This paper presents the results of a comparison of three parallel algebraic multigrid (AMG) preconditioners for structural mechanics applications. In particular, they are interested in investigating both the scalability and robustness of the preconditioners. Numerical results are given for a range of structural mechanics problems with various degrees of difficulty.
Date: May 11, 2004
Creator: Brezina, M; Tong, C & Becker, R
Object Type: Article
System: The UNT Digital Library
Quantifying and Mapping the Digital Divide from Internet point of View (open access)

Quantifying and Mapping the Digital Divide from Internet point of View

None
Date: May 11, 2007
Creator: Cottrell, Les; Khan, Sheryar; Williams, Jerrod; Mehdi, Akbar; Kalim, Umar; Ali, Arshad et al.
Object Type: Article
System: The UNT Digital Library
Understanding How Femtosecond Laser Waveguide Fabrication in Glasses Works (open access)

Understanding How Femtosecond Laser Waveguide Fabrication in Glasses Works

In order to understand the physical processes associated with fs-laser waveguide writing in glass, the effects of the laser repetition rate, the material composition and feature size were studied. The resulting material changes were observed by collecting Raman and fluorescence spectra with a confocal microscope. The guiding behavior of the waveguides was evaluated by measuring near field laser coupling profiles in combination with white light microscopy. Waveguides and Bragg gratings were fabricated in fused silica using pulse repetition rates from 1 kHz to 1 MHz and a wide range of scan speeds and pulse energies. Two types of fluorescence were detected in fused silica, depending on the fabrication conditions. Fluorescence from self trapped exciton (E{prime}{sub {delta}}) defects, centered at 550 nm, were dominant for conditions with low total doses, such as using a 1 kHz laser with a scan speed of 20 {micro}m/s and pulse energies less than 1 {micro}J. For higher doses a broad fluorescence band, centered at 650 nm, associated with non-bridging oxygen hole center (NBOHC) defects was observed. Far fewer NBOHC defects were formed with the 1 MHz laser than with the kHz lasers possibly due to annealing of the defects during writing. We also observed an …
Date: May 11, 2006
Creator: Reichman, W J
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Evaluating the Weatherization Assistance Program in Your State: A Manager's Guide (open access)

Evaluating the Weatherization Assistance Program in Your State: A Manager's Guide

Evaluations of the Weatherization Assistance Program (the Program) serve three major purposes: (1) to document the energy savings and cost effectiveness of the Program, (2) to attract and maintain funding, and (3) to identify opportunities for improving the Program's performance. State managers need detailed and specific information about the performance of their own Program if they are to conduct and market it as effectively as possible. In this evaluation guide, we focus almost entirely on the issues related to the measurement of energy savings. Because the Program's main goal is to reduce the energy use and energy burden of low-income households, the minimum output of an evaluation study should be an estimate of energy savings. If resources are limited, the first priority is to obtain this estimate of savings. Some states may be interested in other issues such as determining Program cost effectiveness, testing the value of various audit types, or identifying the best opportunities for increasing energy savings. Because of limited resources, most will focus only on measuring energy savings.
Date: May 11, 2000
Creator: Berry, L
Object Type: Report
System: The UNT Digital Library
Assessment of Cost Savings of DOE's Return-on-Investment Program (open access)

Assessment of Cost Savings of DOE's Return-on-Investment Program

The US Department of Energy (DOE) Office of Pollution Prevention (EM-77) created a successful internally competed program to fund innovative projects based on projected returns. This is called the Return-on-Investment (ROI) program. EM-77 conducted a successful ROI pilot, developed and implemented sound management practices, and successfully transferred the program to several Operations Offices. Over the past 4 years sites have completed 262 ROI projects (costing $18.8 million) with claimed first-year savings of $88 million and claimed life cycle savings exceeding $300 million. EM-77 requested that Oak Ridge National Laboratory perform an independent evaluation of the site-led, DOE-HQ-funded pollution prevention (P2) ROI program to assist the Department in determining whether claimed savings are real. The approach for conducting this evaluation was to analyze a sample of P2 projects to identify actual project cost savings and other actual benefits--e.g., amount of waste avoided. To determine the projects for review, EM-77 provided a list of EM-funded projects at two Operations Offices: Oak Ridge and Richland. Sixteen projects (eight from each Operations Office) were selected at random from this list for review. Project documentation was requested from the sites, and this was followed by face-to-face interviews with project personnel. of the 16 projects selected …
Date: May 11, 2000
Creator: Yuracko, K. L.
Object Type: Report
System: The UNT Digital Library