States

A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines (open access)

A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.
Date: November 14, 2005
Creator: Westbrook, C K; Pitz, W J & Curran, H J
Object Type: Article
System: The UNT Digital Library
CH-TRU Waste Content Codes (CH-TRUCON) (open access)

CH-TRU Waste Content Codes (CH-TRUCON)

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …
Date: November 20, 2005
Creator: Westinghouse TRU Solutions LLC
Object Type: Report
System: The UNT Digital Library
Is Climate Change Predictable? Really? (open access)

Is Climate Change Predictable? Really?

This project is the first application of a completely different approach to climate modeling, in which new prognostic equations are used to directly compute the evolution of two-point correlations. This project addresses three questions that are critical for the credibility of the science base for climate prediction: (1) What is the variability spectrum at equilibrium? (2) What is the rate of relaxation when subjected to external perturbations? (3) Can variations due to natural processes be distinguished from those due to transient external forces? The technical approach starts with the evolution equation for the probability distribution function and arrives at a prognostic equation for ensemble-mean two-point correlations, bypassing the detailed weather calculation. This work will expand our basic understanding of the theoretical limits of climate prediction and stimulate new experiments to perform with conventional climate models. It will furnish statistical estimates that are inaccessible with conventional climate simulations and likely will raise important new questions about the very nature of climate change and about how (and whether) climate change can be predicted. Solid progress on such issues is vital to the credibility of the science base for climate change research and will provide policymakers evaluating tradeoffs among energy technology options and …
Date: November 14, 2005
Creator: Dannevik, W P & Rotman, D A
Object Type: Report
System: The UNT Digital Library
CFEST Coupled Flow, Energy & Solute Transport Version CFEST005 Theory Guide (open access)

CFEST Coupled Flow, Energy & Solute Transport Version CFEST005 Theory Guide

This document presents the mathematical theory implemented in the CFEST (Coupled Flow, Energy, and Solute Transport) simulator. The simulator is a three-dimensional finite element model that can be used for evaluating flow and solute mass transport. Although the theory for thermal transport is presented in this guide, it has not yet been fully implemented in the simulator. The flow module is capable of simulating both confined and unconfined aquifer systems, as well as constant and variable density fluid flows. For unconfined aquifers, the model uses a moving boundary for the water table, deforming the numerical mesh so that the uppermost nodes are always at the water table. For solute transport, changes in concentration of a single dissolved chemical constituent are computed for advective and hydrodynamic transport, linear sorption represented by a retardation factor, and radioactive decay. Once fully implemented, transport of thermal energy in the groundwater and solid matrix of the aquifer can also be used to model aquifer thermal regimes. Mesh construction employs “collapsible”, hexahedral finite elements in a three-dimensional coordinate system. CFEST uses the Galerkin finite element method to convert the partial differential equations to algebraic form. To solve the coupled equations for momentum, solute and heat transport, …
Date: November 1, 2005
Creator: Freedman, Vicky L.; Chen, Yousu & Gupta, Sumant K.
Object Type: Report
System: The UNT Digital Library
Strangelet Search at the BNL Relativistic Heavy Ion Collider (open access)

Strangelet Search at the BNL Relativistic Heavy Ion Collider

We have searched for strangelets in a triggered sample of 61 million central (top 4percent) Au+Au collisions at sqrt sNN = 200 GeV near beam rapidities at the STAR solenoidal tracker detector at the BNL Relativistic Heavy Ion Collider. We have sensitivity to metastable strangelets with lifetimes of order>_0.1 ns, in contrast to limits over ten times longer in BNL Alternating Gradient Synchrotron (AGS) studies and longer still at the CERN Super Proton Synchrotron (SPS). Upper limits of a few 10-6 to 10-7 per central Au+Au collision are set for strangelets with mass>~;;30 GeV/c2.
Date: November 27, 2005
Creator: Ritter, Ha
Object Type: Article
System: The UNT Digital Library
Comparing FRACHEM and TOUGHREACT for reactive transport modelingof brine-rock interactions in enhanced geothermal systems (EGS) (open access)

Comparing FRACHEM and TOUGHREACT for reactive transport modelingof brine-rock interactions in enhanced geothermal systems (EGS)

Coupled modelling of fluid flow and reactive transport ingeothermal systems is challenging because of reservoir conditions such ashigh temperatures, elevated pressures and sometimes high salinities ofthe formation fluids. Thermal hydrological-chemical (THC) codes, such asFRACHEM and TOUGHREACT, have been developed to evaluate the long-termhydrothermal and chemical evolution of exploited reservoirs. In thisstudy, the two codes were applied to model the same geothermal reservoir,to forecast reservoir evolution using respective thermodynamic andkinetic input data. A recent (unreleased) TOUGHREACT version allows theuse of either an extended Debye-Hu?ckel or Pitzer activity model forcalculating activity coefficients, while FRACHEM was designed to use thePitzer formalism. Comparison of models results indicate that differencesin thermodynamic equilibrium constants, activity coefficients andkinetics models can result in significant differences in predictedmineral precipitation behaviour and reservoir-porosity evolution.Differences in the calculation schemes typically produce less differencein model outputs than differences in input thermodynamic and kineticdata, with model results being particularly sensitive to differences inion-interaction parameters for highsalinity systems.
Date: November 15, 2005
Creator: Andre, L.; Spycher, N.; Xu, T.; Pruess, K. & Vuataz, F.-D.
Object Type: Article
System: The UNT Digital Library
Photofragment Coincidence Imaging of Small I- (H2O)n Clusters Excited to the Charge-transfer-to-solvent State (open access)

Photofragment Coincidence Imaging of Small I- (H2O)n Clusters Excited to the Charge-transfer-to-solvent State

The photodissociation dynamics of small I{sup -}(H{sub 2}O){sub n} (n = 2-5) clusters excited to their charge-transfer-to-solvent (CTTS) states have been studied using photofragment coincidence imaging. Upon excitation to the CTTS state, two photodissociation channels were observed. The major channel ({approx}90%) is a 2-body process forming neutral I + (H{sub 2}O){sub n} photofragments, and the minor channel is a 3-body process forming I + (H{sub 2}O){sub n-1} + H{sub 2}O fragments. Both process display translational energy (P(E{sub T})) distributions peaking at E{sub T} = 0 with little available energy partitioned into translation. Clusters excited to the detachment continuum rather than to the CTTS state display the same two channels with similar P(E{sub T}) distributions. The observation of similar P(E{sub T}) distributions from the two sets of experiments suggests that in the CTTS experiments, I atom loss occurs after autodetachment of the excited (I(H{sub 2}O){sub n}{sup -})* cluster, or, less probably, that the presence of the excess electron has little effect on the departing I atom.
Date: November 9, 2005
Creator: Neumark, D. E. Szpunar, K. E. Kautzman, A. E. Faulhaber, and D. M.; Kautzman, K.E.; Faulhaber, A.E. & Faulhaber, A.E.
Object Type: Article
System: The UNT Digital Library
Atmospheric Radiation Measurement Climate Research Facility Annual Report 2006 (open access)

Atmospheric Radiation Measurement Climate Research Facility Annual Report 2006

This annual report describes the purpose and structure of the ARM Climate Research Facility and ARM Science programs and presents key accomplishments in 2006. Noteworthy scientific and infrastructure accomplishments in 2006 include: • Collaborating with the Australian Bureau of Meteorology to lead the Tropical Warm Pool-International Cloud Experiment, a major international field campaign held in Darwin, Australia • Successfully deploying the ARM Mobile Facility in Niger, Africa • Developing the new ARM Aerial Vehicles Program (AVP) to provide airborne measurements • Publishing a new finding on the impacts of aerosols on surface energy budget in polar latitudes • Mitigating a long-standing double-Intertropical Convergence Zone problem in climate models using ARM data and a new cumulus parameterization scheme.
Date: November 30, 2005
Creator: Roeder, LR
Object Type: Report
System: The UNT Digital Library
Compliant membranes for the development of MEMS dual-backplate capacitive microphone using the SUMMiT V fabrication process. (open access)

Compliant membranes for the development of MEMS dual-backplate capacitive microphone using the SUMMiT V fabrication process.

The objective of this project is the investigation of compliant membranes for the development of a MicroElectrical Mechanical Systems (MEMS) microphone using the Sandia Ultraplanar, Multilevel MEMS Technology (SUMMiT V) fabrication process. The microphone is a dual-backplate capacitive microphone utilizing electrostatic force feedback. The microphone consists of a diaphragm and two porous backplates, one on either side of the diaphragm. This forms a capacitor between the diaphragm and each backplate. As the incident pressure deflects the diaphragm, the value of each capacitor will change, thus resulting in an electrical output. Feedback may be used in this device by applying a voltage between the diaphragm and the backplates to balance the incident pressure keeping the diaphragm stationary. The SUMMiT V fabrication process is unique in that it can meet the fabrication requirements of this project. All five layers of polysilicon are used in the fabrication of this device. The SUMMiT V process has been optimized to provide low-stress mechanical layers that are ideal for the construction of the microphone's diaphragm. The use of chemical mechanical polishing in the SUMMiT V process results in extremely flat structural layers and uniform spacing between the layers, both of which are critical to the successful …
Date: November 1, 2005
Creator: Martin, David (University of Florida, Gainesville, FL)
Object Type: Report
System: The UNT Digital Library
Time-resolved soft-x-ray spectroscopy of a magnetic octupole transition in nickel-like xenon, cesium, and barium ions (open access)

Time-resolved soft-x-ray spectroscopy of a magnetic octupole transition in nickel-like xenon, cesium, and barium ions

A microcalorimeter with event mode capability for time-resolved soft-x-ray spectroscopy, and a high-resolution flat-field EUV spectrometer have been employed at the Livermore EBIT-I electron beam ion trap for observations and wavelength measurements of M1, E2, and M3 decays of long-lived levels in the Ni-like ions Xe{sup 26+}, Cs{sup 27+}, and Ba{sup 28+}. Of particular interest is the lowest excited level, 3d{sup 9}4s {sup 3}D{sub 3}, which can only decay via a magnetic octupole (M3) transition. For this level in Xe an excitation energy of (590.40 {+-} 0.03eV) and a level lifetime of (11.5 {+-} 0.5 ms) have been determined.
Date: November 11, 2005
Creator: Trabert, E; Beiersdorfer, P; Brown, G V; Boyce, K; Kelley, R L; Kilbourne, C A et al.
Object Type: Article
System: The UNT Digital Library
Energy and visual comfort performance of electrochromic windowswith overhangs (open access)

Energy and visual comfort performance of electrochromic windowswith overhangs

DOE-2 building energy simulations were conducted to determine if there were practical architectural and control strategy solutions that would enable electrochromic (EC) windows to significantly improve visual comfort without eroding energy-efficiency benefits. EC windows were combined with overhangs since opaque overhangs provide protection from direct sun which EC windows are unable to do alone. The window wall was divided into an upper and lower aperture so that various combinations of overhang position and control strategies could be considered. The overhang was positioned either at the top of the upper window aperture or between the upper and lower apertures. Overhang depth was varied. EC control strategies were fully bleached at all times, modulated based on incident vertical solar radiation limits, or modulated to meet the design work plane illuminance with daylight. The EC performance was compared to a state-of-the-art spectrally selective low-e window with the same divided window wall, window size, and overhang as the EC configuration. The reference window was also combined with an interior shade which was manually deployed to control glare and direct sun. Both systems had the same daylighting control system to dim the electric lighting. Results were given for south-facing private offices in a typical commercial …
Date: November 3, 2005
Creator: Lee, E.S. & Tavil, A.
Object Type: Article
System: The UNT Digital Library
Bacillus atrophaeus Outer Spore Coat Assembly and Ultrastructure (open access)

Bacillus atrophaeus Outer Spore Coat Assembly and Ultrastructure

Our previous atomic force microscopy (AFM) studies successfully visualized native Bacillus atrophaeus spore coat ultrastructure and surface morphology. We have shown that the outer spore coat surface is formed by a crystalline array of {approx}11 nm thick rodlets, having a periodicity of {approx}8 nm. We present here further AFM ultrastructural investigations of air-dried and fully hydrated spore surface architecture. In the rodlet layer, planar and point defects, as well as domain boundaries, similar to those described for inorganic and macromolecular crystals, were identified. For several Bacillus species, rodlet structure assembly and architectural variation appear to be a consequence of species-specific nucleation and crystallization mechanisms that regulate the formation of the outer spore coat. We propose a unifying mechanism for nucleation and self-assembly of this crystalline layer on the outer spore coat surface.
Date: November 21, 2005
Creator: Plomp, M; Leighton, T J; Wheeler, K E; Pitesky, M E & Malkin, A J
Object Type: Article
System: The UNT Digital Library
Concealed Threat Detection at Multiple Frames-per-second (open access)

Concealed Threat Detection at Multiple Frames-per-second

In this LDRD project, our research purpose is to investigate the science and technology necessary to enable real-time array imaging as a rapid way to detect hidden threats through obscurants such as smoke, fog, walls, doors, and clothing. The goal of this research is to augment the capabilities of protective forces in concealed threat detection. In the current context, threats include people as well as weapons. In most cases, security personnel must make very fast assessments of a threat based upon limited amount of data. Among other attributes, UWB has been shown and quantified to penetrate and propagate through many materials (wood, some concretes, non-metallic building materials, some soils, etc.) while maintaining high range resolution. We have build collaborations with university partners and government agencies. We have considered the impact of psychometrics on target recognition and identification. Specifically we have formulated images in real-time that will engage the user's vision system in a more active way to enhance image interpretation capabilities. In this project, we are researching the use of real time (field programmable gate arrays) integrated with high resolution (cm scale), ultra wide band (UWB) electromagnetic signals for imaging personnel through smoke and walls. We evaluated the ability of …
Date: November 8, 2005
Creator: Chang, J T
Object Type: Report
System: The UNT Digital Library
An Optimization and Assessment on DG adoption in JapanesePrototype Buildings (open access)

An Optimization and Assessment on DG adoption in JapanesePrototype Buildings

This research investigates a method of choosing economicallyoptimal DER, expanding on prior studies at the Berkeley Lab using the DERdesign optimization program, the Distributed Energy Resources CustomerAdoption Model (DER-CAM). DER-CAM finds the optimal combination ofinstalled equipment from available DER technologies, given prevailingutility tariffs, site electrical and thermal loads, and a menu ofavailable equipment. It provides a global optimization, albeit idealized,that shows how the site energy load scan be served at minimum cost byselection and operation of on-site generation, heat recovery, andcooling. Five prototype Japanese commercial buildings are examined andDER-CAM applied to select thee conomically optimal DER system for each.The five building types are office, hospital, hotel, retail, and sportsfacility. Based on the optimization results, energy and emissionreductions are evaluated. Furthermore, a Japan-U.S. comparison study ofpolicy, technology, and utility tariffs relevant to DER installation ispresented. Significant decreases in fuel consumption, carbon emissions,and energy costs were seen in the DER-CAM results. Savings were mostnoticeable in the sports facility, followed by the hospital, hotel, andoffice building.
Date: November 30, 2005
Creator: Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun & Nishida,Masaru
Object Type: Article
System: The UNT Digital Library
Laboratory measurements on core-scale sediment/hydrate samples topredice reservoir behavior (open access)

Laboratory measurements on core-scale sediment/hydrate samples topredice reservoir behavior

Measurements on hydrate-bearing laboratory and field samplesare necessary in order to provide realistic bounds on parameters used innumerically modeling the production of natural gas from hydrate-bearingreservoirs. The needed parameters include thermal conductivity,permeability, relative permeability-saturation(s) relationships, andcapillary pressure-saturation(s) relationships. We have developed atechnique to make hydrate-bearing samples ranging in scale from coreplug-size to core-size in the laboratory to facilitate making thesemeasurements. In addition to pressure and temperature measurements, weuse x-ray computed tomography scanning to provide high-resolution dataproviding insights on processes occurring in our samples. Several methodsare available to make gas hydrates in the laboratory, and we expect thatthe method used to make the hydrate will impact the behavior of thehydrate sample, and the parameters measured.
Date: November 2, 2005
Creator: Kneafsey, Timothy J.; Seol, Yongkoo; Moridis, George J.; Tomutsa,Liviu & Freifeld, Barry M.
Object Type: Report
System: The UNT Digital Library
Avian Field Guide and Checklist for Kunsan Air Base, Korea. (open access)

Avian Field Guide and Checklist for Kunsan Air Base, Korea.

This report summarizes the results of the avian surveys conducted at Kunsan Air Base (AB). This on-going survey is conducted to comply with requirements of the Environmental Governing Standards (EGS) for the Republic of Korea, the Integrated Natural Resources Management Plan (INRMP) for Kunsan AB, and the 8th Fighter Wing's Bird Aircraft Strike Hazard (BASH) Plan. One hundred sixteen bird species representing 34 families were identified and recorded. Seven species are designated as Cultural Property Monuments, and their protection is accorded by the Korean Ministry of Culture and Tourism. Six species appear on the Korean Association for Conservation of Nature's(KACN's) list of Reserved Wild Species and are protected by the Korean Ministry of Environment. Combined, only ten different species are Republic of Korea (ROK)-protected because the Eurasian Spoonbill, Peregrine Falcon, and Eurasian Oystercatcher are listed by both agencies. The primary objective of the avian survey at Kunsan AB was to determine what species of birds are present on the airfield and their respective habitat requirements during the critical seasons of the year. This requirement is specified in Annex C.4.a.(1-4) of the 8th Fighter Wing BASH Plan(8FWOPLAN 91-202). The second objective was to initiate surveys to determine what bird species are …
Date: November 15, 2005
Creator: Levenson, J. B. & Assessment, Environmental
Object Type: Report
System: The UNT Digital Library
Surface Temperature Humidity Reference System Handbook - November 2005 (open access)

Surface Temperature Humidity Reference System Handbook - November 2005

The Surface Temperature and Humidity Reference (SURTHREF) system is intended to provide accurate reference values of ambient temperature and relative humidity for comparison with radiosonde prelaunch values.
Date: November 30, 2005
Creator: Ritsche, M. T.
Object Type: Report
System: The UNT Digital Library
Incorporating anisotropic electronic structure in crystallographic determination of complex metals: iron and plutonium (open access)

Incorporating anisotropic electronic structure in crystallographic determination of complex metals: iron and plutonium

None
Date: November 2, 2005
Creator: Moore, K; Laughlin, D; Soderlind, P & Schwartz, A
Object Type: Article
System: The UNT Digital Library
Piezoelectric field in strained GaAs. (open access)

Piezoelectric field in strained GaAs.

This report describes an investigation of the piezoelectric field in strained bulk GaAs. The bound charge distribution is calculated and suitable electrode configurations are proposed for (1) uniaxial and (2) biaxial strain. The screening of the piezoelectric field is studied for different impurity concentrations and sample lengths. Electric current due to the piezoelectric field is calculated for the cases of (1) fixed strain and (2) strain varying in time at a constant rate.
Date: November 1, 2005
Creator: Chow, Weng Wah & Wieczorek, Sebastian Maciej
Object Type: Report
System: The UNT Digital Library
Optimal Model of Distributed Energy System by Using GAMS and CaseStudy (open access)

Optimal Model of Distributed Energy System by Using GAMS and CaseStudy

This paper adopts optimal model which used GAMS to developmethods and tools for conducting an integrated assessment of DER system.Three cases were studied. Energy-saving, environmental and economicefficiency were evaluated. The results of the simulation can besummarized as follows: 1) For the current system, optimal operating timeis about 4,132 hours per year, and from 8 am to 22 pm everyday. 2) It iseconomical when electricity price increases or gas price decreases. 3)According to the load function of system, energy-saving, environmentaland economic efficiency will have amaximum value at optimal operatingtime. 4) Compared with exhaust heat efficiency, power generationefficiency has more influence to the economic efficiency and CO2reduction when the total efficiency is fixed.
Date: November 30, 2005
Creator: Yang, Yongwen; Gao, Weijun; Ruan, Yingjun; Xuan, Ji; Zhou, Nan & Marnay, Chris
Object Type: Article
System: The UNT Digital Library
Motivation, description, and summary status of geomechanical andgeochemical modeling studies in Task D of the InternationalDECOVALEX-THMC Project (open access)

Motivation, description, and summary status of geomechanical andgeochemical modeling studies in Task D of the InternationalDECOVALEX-THMC Project

The DECOVALEX project is an international cooperativeproject initiated by SKI, the Swedish Nuclear Power Inspectorate, withparticipation of about 10 international organizations. The general goalof this project is to encourage multidisciplinary interactive andcooperative research on modelling coupledthermo-hydro-mechanical-chemical (THMC) processes in geologic formationsin support of the performance assessment for underground storage ofradioactive waste. One of the research tasks, initiated in 2004 by theU.S. Department of Energy (DOE), addresses the long-term impact ofgeomechanical and geochemical processes on the flow conditions near wasteemplacement tunnels. Within this task, four international research teamsconduct predictive analysis of the coupled processes in two genericrepositories, using multiple approaches and different computer codes.Below, we give an overview of the research task and report its currentstatus.
Date: November 15, 2005
Creator: Birkholzer, J.T.; Barr, D.; Rutqvist, J. & Sonnenthal, E.
Object Type: Article
System: The UNT Digital Library
Probing the Structure-Function Relationships of Microbial Systems (open access)

Probing the Structure-Function Relationships of Microbial Systems

The elucidation of microbial surface architecture and function is critical to determining mechanisms of pathogenesis, immune response, physicochemical properties, environmental resistance and development of countermeasures against bioterrorist agents. We have utilized high-resolution in vitro AFM for studies of structure, assembly, function and environmental dynamics of several microbial systems including bacteria and bacterial spores. Lateral resolutions of {approx}2.0 nm were achieved on pathogens, in vitro. We have demonstrated, using various species of Bacillus and Clostridium bacterial spores, that in vitro AFM can address spatially explicit spore coat protein interactions, structural dynamics in response to environmental changes, and the life cycle of pathogens at near-molecular resolution under physiological conditions. We found that strikingly different species-dependent crystalline structures of the spore coat appear to be a consequence of nucleation and crystallization mechanisms that regulate the assembly of the outer spore coat, and we proposed a unifying mechanism for outer spore coat self-assembly. Furthermore, we revealed molecular-scale transformations of the spore coat during the germination process, which include profound, previously unrecognized changes of the spore coat. We will present data on the direct visualization of stress-induced environmental response of metal-resistant Arthrobacter oxydans bacteria to Cr (VI) exposure, resulting in the formation of a supramolecular …
Date: November 3, 2005
Creator: Plomp, M; Leighton, T J; Holman, H & Malkin, A J
Object Type: Article
System: The UNT Digital Library
Development of Damp-Heat Resistant Self-Primed EVA and Non-EVA Encapsulant Formulations at NREL (open access)

Development of Damp-Heat Resistant Self-Primed EVA and Non-EVA Encapsulant Formulations at NREL

Self-primed ethylene-vinyl acetate (EVA) and non-EVA (PMG) encapsulant formulations were developed that have greater resistance to damp heat exposure at 85 deg C and 85% relative humidity (RH) (in terms of adhesion strength to glass substrates) than a commonly used commercial EVA product. The self-primed EVA formulations were developed on the basis of high-performing glass priming formulations that have previously proven to significantly enhance the adhesion strength of unprimed and primed EVA films on glass substrates during damp heat exposure. The PMG encapsulant formulations were based on an ethylene-methylacrylate copolymer containing glycidyl methacrylate.
Date: November 1, 2005
Creator: Pern, F. J. & Jorgensen, G. J.
Object Type: Article
System: The UNT Digital Library
III-V Growth on Silicon Toward a Multijunction Cell (open access)

III-V Growth on Silicon Toward a Multijunction Cell

A III-V on Si multijunction solar cell promises high efficiency at relatively low cost. The challenges to epitaxial growth of high-quality III-Vs on Si, though, are extensive. Lattice-matched (LM) dilute-nitride GaNPAs solar cells have been grown on Si, but their performance is limited by defects related to the nitrogen. Advances in the growth of lattice-mismatched (LMM) materials make more traditional III-Vs, such as GaInP and GaAsP, very attractive for use in multijunction solar cells on silicon.
Date: November 1, 2005
Creator: Geisz, J.; Olson, J.; McMahon, W.; Friedman, D.; Kibbler, A.; Kramer, C. et al.
Object Type: Article
System: The UNT Digital Library