Extending Performance and Evaluating Risks of PV Systems Failure Using a Fault Tree and Event Tree Approach: Analysis of the Possible Application (open access)

Extending Performance and Evaluating Risks of PV Systems Failure Using a Fault Tree and Event Tree Approach: Analysis of the Possible Application

Performance and reliability of photovoltaic (PV) systems are important issues in the overall evaluation of a PV plant and its components. While performance is connected to the amount of energy produced by the PV installation in the working environmental conditions, reliability impacts the availability of the system to produce the expected amount of energy. In both cases, the evaluation should be done considering information and data coming from indoor as well as outdoor tests. In this paper a way of re-thinking performance, giving it a probabilistic connotation, and connecting the two concepts of performance and reliability is proposed. The paper follows a theoretical approach and discusses the way to obtaining such information, facing benefits and problems. The proposed probabilistic performance accounts for the probability of the system to function correctly, thus passing through the complementary evaluation of the probability of system malfunctions and consequences. Scenarios have to be identified where the system is not functioning properly or at all. They are expected to be combined in a probabilistic safety analysis (PSA) based approach, providing not only the required probability, but also being capable of giving a prioritization of the risks and the most dominant scenario associated to a specific situation. …
Date: June 3, 2012
Creator: A., Colli
Object Type: Article
System: The UNT Digital Library
DEMONSTRATION OF MIXING AND TRANSFERRING SETTLING COHESIVE SLURRY SIMULANTS IN THE AY-102 TANK (open access)

DEMONSTRATION OF MIXING AND TRANSFERRING SETTLING COHESIVE SLURRY SIMULANTS IN THE AY-102 TANK

In support of Hanford's feed delivery of high level waste (HLW) to the Waste Treatment and Immobilization Plant (WTP), pilot-scale testing and demonstrations with simulants containing cohesive particles were performed as a joint collaboration between Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL) staff. The objective of the demonstrations was to determine the impact that cohesive particle interactions in the simulants, and the resulting non-Newtonian rheology, have on tank mixing and batch transfer of large and dense seed particles. The work addressed the impacts cohesive simulants have on mixing and batch transfer performance in a pilot-scale system. Kaolin slurries with a range of wt% concentrations to vary the Bingham yield stress were used in all the non-Newtonian simulants. To study the effects of just increasing the liquid viscosity (no yield stress) on mixing and batch transfers, a glycerol/water mixture was used. Stainless steel 100 micron particles were used as seed particles due to their density and their contrasting color to the kaolin and glycerol. In support of Hanford's waste certification and delivery of tank waste to the Waste Treatment and Immobilization Plant (WTP), Savannah River National Laboratory (SRNL) was tasked by Washington River Protection Solutions (WRPS) …
Date: January 3, 2012
Creator: Adamson, D. & Gauglitz, P.
Object Type: Article
System: The UNT Digital Library
ILC RF System R and D (open access)

ILC RF System R and D

The Linac Group at SLAC is actively pursuing a broad range of R&D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system proposed for the ILC linacs. Current activities include the long-term evaluation of a 120 kV Marx Modulator driving a 10 MW Multi-Beam Klystron, design of a second-generation Marx Modulator, testing of a sheet-beam gun and beam transport system for a klystron, construction of an rf distribution system with remotely-adjustable power tapoffs, and development of a system to combine the power from many klystrons in low-loss circular waveguide where it would be tapped-off periodically to power groups of cavities. This paper surveys progress during the past few years.
Date: July 3, 2012
Creator: Adolphsen, Chris
Object Type: Article
System: The UNT Digital Library
Prototyping Energy Efficient Thermo-Magnetic & Induction Hardening for Heat Treat & Net Shape Forming Applications (open access)

Prototyping Energy Efficient Thermo-Magnetic & Induction Hardening for Heat Treat & Net Shape Forming Applications

Within this project, Eaton undertook the task of bringing about significant impact with respect to sustainability. One of the major goals for the Department of Energy is to achieve energy savings with a corresponding reduction in carbon foot print. The use of a coupled induction heat treatment with high magnetic field heat treatment makes possible not only improved performance alloys, but with faster processing times and lower processing energy, as well. With this technology, substitution of lower cost alloys for more exotic alloys became a possibility; microstructure could be tailored for improved magnetic properties or wear resistance or mechanical performance, as needed. A prototype commercial unit has been developed to conduct processing of materials. Testing of this equipment has been conducted and results demonstrate the feasibility for industrial commercialization.
Date: August 3, 2012
Creator: Ahmad, Aquil
Object Type: Report
System: The UNT Digital Library
Collaboratory for Multiscale Chemical Science (CMCS) (open access)

Collaboratory for Multiscale Chemical Science (CMCS)

This document provides details of the contributions made by NIST to the Collaboratory for Multiscale Chemical Science (CMCS) project. In particular, efforts related to the provision of data (and software in support of that data) relevant to the combustion pilot project are described.
Date: July 3, 2012
Creator: Allison, Thomas C.
Object Type: Report
System: The UNT Digital Library
Building an Efficient Model for Afterburn Energy Release (open access)

Building an Efficient Model for Afterburn Energy Release

Many explosives will release additional energy after detonation as the detonation products mix with the ambient environment. This additional energy release, referred to as afterburn, is due to combustion of undetonated fuel with ambient oxygen. While the detonation energy release occurs on a time scale of microseconds, the afterburn energy release occurs on a time scale of milliseconds with a potentially varying energy release rate depending upon the local temperature and pressure. This afterburn energy release is not accounted for in typical equations of state, such as the Jones-Wilkins-Lee (JWL) model, used for modeling the detonation of explosives. Here we construct a straightforward and efficient approach, based on experiments and theory, to account for this additional energy release in a way that is tractable for large finite element fluid-structure problems. Barometric calorimeter experiments have been executed in both nitrogen and air environments to investigate the characteristics of afterburn for C-4 and other materials. These tests, which provide pressure time histories, along with theoretical and analytical solutions provide an engineering basis for modeling afterburn with numerical hydrocodes. It is toward this end that we have constructed a modified JWL equation of state to account for afterburn effects on the response of …
Date: February 3, 2012
Creator: Alves, S; Kuhl, A; Najjar, F; Tringe, J; McMichael, L & Glascoe, L
Object Type: Article
System: The UNT Digital Library
Renewable Energy and Environmental Sustainability Using Biomass From Dairy and Beef Animal Production: Final Report, Volume 1 (open access)

Renewable Energy and Environmental Sustainability Using Biomass From Dairy and Beef Animal Production: Final Report, Volume 1

The Texas Panhandle is regarded as the 'Cattle Feeding Capital of the World', producing 42% of the fed beef cattle in the United States within a 200-mile radius of Amarillo generating more than 5 million tons of feedlot manure/year. Apart from feedlots, the Bosque River Region in Erath County, just north of Waco, Texas with about 110,000 dairy cattle in over 250 dairies, produces 1.8 million tons of manure biomass (excreted plus bedding) per year. While the feedlot manure has been used extensively for irrigated and dry land crop production, most dairies, as well as other concentrated animal feeding operations (CAFO's), the dairy farms utilize large lagoon areas to store wet animal biomass. Water runoff from these lagoons has been held responsible for the increased concentration of phosphorus and other contaminates in the Bosque River which drains into Lake Waco - the primary source of potable water for Waco's 108,500 people. The concentrated animal feeding operations may lead to land, water, and air pollution if waste handling systems and storage and treatment structures are not properly managed. Manure-based biomass (MBB) has the potential to be a source of green energy at large coal-fired power plants and on smaller-scale combustion systems …
Date: May 3, 2012
Creator: Annamalai, Kalyan; Sweeten, John M.; Auvermann, Brent W.; Muhtar, Saqib; Caperada, Sergio; Engler, Cady R. et al.
Object Type: Report
System: The UNT Digital Library
NUCLEAR ENERGY AND ASTROPHYSICS APPLICATIONS OF ENDF/B-VII.1 EVALUATED NUCLEAR LIBRARY (open access)

NUCLEAR ENERGY AND ASTROPHYSICS APPLICATIONS OF ENDF/B-VII.1 EVALUATED NUCLEAR LIBRARY

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Date: September 3, 2012
Creator: B., Pritychenko
Object Type: Article
System: The UNT Digital Library
Suicide Prevention Efforts of the Veterans Health Administration (open access)

Suicide Prevention Efforts of the Veterans Health Administration

Responsibility for prevention of veteran suicide lies primarily with the Veterans Health Administration (VHA), within the Department of Veterans Affairs (VA). The VHA Strategic Plan for Suicide Prevention is based on a public health framework, which has three major components: (1) surveillance, (2) risk and protective factors, and (3) prevention interventions. This report identifies challenges the VHA faces in each component of suicide prevention and discusses potential issues for Congress.
Date: February 3, 2012
Creator: Bagalman, Erin
Object Type: Report
System: The UNT Digital Library
Cellulose and cellobiose: adventures of a wandering organic chemist in theoretical chemistry (open access)

Cellulose and cellobiose: adventures of a wandering organic chemist in theoretical chemistry

The energies arising from the rotation of free hydroxyl groups in the central glucose residue of a cellulose crystalline assembly, calculated using RHF, DFT, and FMO2/MP2 methods, will be presented. In addition, interactions of this central glucose residue with some of the surrounding residues (selected on the basis of the interaction strengths) are analyzed. The mechanism of acid-catalyzed hydrolysis of cellobiose, which is the repeating unit of cellulose. Energies corresponding to the different steps of this mechanism calculated using RHF and DFT are compared with those previously reported using molecular dynamics calculations and with experimental data.
Date: April 3, 2012
Creator: Baluyut, John
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Trade Law: An Introduction to Selected International Agreements and U.S. Laws (open access)

Trade Law: An Introduction to Selected International Agreements and U.S. Laws

This report is an introductory overview of the legal framework governing trade-related measures. The agreements and laws selected for discussion are those most commonly implicated by U.S. trade interests, but there are U.S. trade laws and obligations beyond those reviewed in this report.
Date: April 3, 2012
Creator: Barbour, Emily C.
Object Type: Report
System: The UNT Digital Library
2012 MITOCHONDRIA AND CHLOROPLASTS GORDON RESEARCH CONFERENCE & GORDON RESEARCH SEMINAR, JULY 29 - AUGUST 3, 2012 (open access)

2012 MITOCHONDRIA AND CHLOROPLASTS GORDON RESEARCH CONFERENCE & GORDON RESEARCH SEMINAR, JULY 29 - AUGUST 3, 2012

The 2012 Gordon Research Conference on Mitochondria and Chloroplasts will assemble an international group of scientists investigating fundamental properties of these organelles, and their integration into broader physiological processes. The conference will emphasize the many commonalities between mitochondria and chloroplasts: their evolution from bacterial endosymbionts, their genomes and gene expression systems, their energy transducing membranes whose proteins derive from both nuclear and organellar genes, the challenge of maintaining organelle integrity in the presence of the reactive oxygen species that are generated during energy transduction, their incorporation into organismal signaling pathways, and more. The conference will bring together investigators working in animal, plant, fungal and protozoan systems who specialize in cell biology, genetics, biochemistry, physiology, proteomics, genomics, and structural biology. As such, this conference will provide a unique forum that engenders cross-disciplinary discussions concerning the biogenesis, dynamics, and regulation of these key cellular structures. By fostering interactions among mammalian, fungal and plant organellar biologists, this conference also provides a conduit for the transmission of mechanistic insights obtained in model organisms to applications in medicine and agriculture. The 2012 conference will highlight areas that are moving rapidly and emerging themes. These include new insights into the ultrastructure and organization of the energy …
Date: August 3, 2012
Creator: Barkan, Alice
Object Type: Article
System: The UNT Digital Library
Ring Walking/Oxidative Addition Reactions for the Controlled Synthesis of Conjugated Polymers (open access)

Ring Walking/Oxidative Addition Reactions for the Controlled Synthesis of Conjugated Polymers

Power conversion efficiencies of plastic solar cells depend strongly on the molecular weight characteristics of the semiconducting polymers used for their fabrication. The synthesis of these materials typically relies on transition metal mediated catalytic reactions. In many instances, the ideal structures cannot be attained because of deficiencies in these reactions, particularly when it comes to being able to achieve high number average molecular weights and narrow molecular weight distributions. Another important conjugated polymer structure of interest is one in which a single functional group is attached at the end group of the chain. Such systems would be ideal for modifying surface properties at interfaces and for labeling biomolecular probes used in fluorescent biosensors. To respond to the challenges above, our efforts have centered on the design of homogenous transition metal complexes that are easy to prepare and effective in carrying out living, or quasi-living, condensative chain polymerization reactions. The key mechanistic challenge for the success of this reaction is to force the insertion of one monomer unit at a time via a process that involves migration of the transition metal-containing fragment to one terminus of the polymer chain. Chain growth characteristics are therefore favored when the metal does not dissociate …
Date: April 3, 2012
Creator: Bazan, Guillermo C
Object Type: Report
System: The UNT Digital Library
Workshops on Science Enabled by a Coherent, CW, Synchrotron X-ray Source, June 2011 (open access)

Workshops on Science Enabled by a Coherent, CW, Synchrotron X-ray Source, June 2011

In June of 2011 we held six two-day workshops called "XDL-2011: Science at the Hard X-ray Diffraction Limit". The six workshops covered (1) Diffraction-based imaging techniques, (2) Biomolecular structure from non-crystalline materials, (3) Ultra-fast science, (4) High-pressure science, (5) Materials research with nano-beams and (6) X-ray photon correlation spectroscopy (XPCS), In each workshop, invited speaker from around the world presented examples of novel experiments that require a CW, diffraction-limited source. During the workshop, each invited speaker provided a one-page description of the experiment and an illustrative graphic. The experiments identified by the workshops demonstrate the broad and deep scientific case for a CW coherent synchrotron x-ray source. The next step is to perform detailed simulations of the best of these ideas to test them quantitatively and to guide detailed x-ray beam-line designs. These designs are the first step toward developing detailed facility designs and cost estimates.
Date: January 3, 2012
Creator: Brock, Joel
Object Type: Article
System: The UNT Digital Library
Exotic Effects at the Charm Threshold and Other Novel Physics Topics at JLab-12 GeV (open access)

Exotic Effects at the Charm Threshold and Other Novel Physics Topics at JLab-12 GeV

I briefly survey a number of novel hadron physics topics which can be investigated with the 12 GeV upgrade at J-Lab. The topics include new the formation of exotic heavy quark resonances accessible above the charm threshold, intrinsic charm and strangeness phenomena, the exclusive Sivers effect, hidden-color Fock states of nuclei, local two-photon interactions in deeply virtual Compton scattering, and non-universal antishadowing.
Date: May 3, 2012
Creator: Brodsky, Stanley J.
Object Type: Article
System: The UNT Digital Library
Religion and the Workplace: Legal Analysis of Title VII of the Civil Rights Act of 1964 as It Applies to Religion and Religious Organizations (open access)

Religion and the Workplace: Legal Analysis of Title VII of the Civil Rights Act of 1964 as It Applies to Religion and Religious Organizations

This report reviews the scope of Title VII's prohibition on religious discrimination, its exemptions for religious organizations, and its requirements for accommodations. It also analyzes the exemptions available to religious organizations for the non-discrimination requirements. Finally, it addresses protections based on Title VII's religious exemption that have been included in the proposed Employment Non-Discrimination Act.
Date: April 3, 2012
Creator: Brougher, Cynthia
Object Type: Report
System: The UNT Digital Library
FEMA's Community Disaster Loan Program: History, Analysis, and Issues for Congress (open access)

FEMA's Community Disaster Loan Program: History, Analysis, and Issues for Congress

This report compares and analyzes three different categories of loans issued in different time periods in the program's history: "traditional" loans issued between 1974 and 2005, in 2007, and between 2009 and 2011 (TCDLs); "special" (SCDLs) loans issued in 2005-2006 following Hurricanes Katrina and Rita; and loans issued under unique provisions in 2008 (2008 CDLs).
Date: July 3, 2012
Creator: Brown, Jared T.
Object Type: Report
System: The UNT Digital Library
Electronic Employment Eligibility Verification (open access)

Electronic Employment Eligibility Verification

This report is categorized into Five Categories: (I) Background, (II) E-Verify, (III) Recent Proposals on Electronic Employment Verification, (IV) Policy Considerations and (V) Conclusion.
Date: May 3, 2012
Creator: Bruno, Andorra
Object Type: Report
System: The UNT Digital Library
Resilience: Theory and Application. (open access)

Resilience: Theory and Application.

There is strong agreement among policymakers, practitioners, and academic researchers that the concept of resilience must play a major role in assessing the extent to which various entities - critical infrastructure owners and operators, communities, regions, and the Nation - are prepared to respond to and recover from the full range of threats they face. Despite this agreement, consensus regarding important issues, such as how resilience should be defined, assessed, and measured, is lacking. The analysis presented here is part of a broader research effort to develop and implement assessments of resilience at the asset/facility and community/regional levels. The literature contains various definitions of resilience. Some studies have defined resilience as the ability of an entity to recover, or 'bounce back,' from the adverse effects of a natural or manmade threat. Such a definition assumes that actions taken prior to the occurrence of an adverse event - actions typically associated with resistance and anticipation - are not properly included as determinants of resilience. Other analyses, in contrast, include one or more of these actions in their definitions. To accommodate these different definitions, we recognize a subset of resistance- and anticipation-related actions that are taken based on the assumption that an …
Date: February 3, 2012
Creator: Carlson, J. L.; Haffenden, R. A.; Bassett, G. W.; Buehring, W. A.; Collins, M. J., III; Folga, S. M. et al.
Object Type: Report
System: The UNT Digital Library
Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: Wavelength, pressure and temperature dependency. (open access)

Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: Wavelength, pressure and temperature dependency.

Several absorption bands exist in the VUV region of Carbon monoxide (CO). Emission spectra indicate that these bands are all predissociative. An experimental investigation of CO photodissociation by vacuum ultraviolet photons (90 to 108 nm; ~13 to 11 eV) from the Advanced Light Source Synchrotron and direct measurement of the associated oxygen isotopic composition of the products are presented here. A wavelength dependency of the oxygen isotopic composition in the photodissociation product was observed. Slope values (δ'{sup 18}O/ δ'{sup 17}O) ranging from 0.76 to 1.32 were observed in oxygen three-isotope space (δ'{sup 18}O vs. δ'{sup 17}O) which correlated with increasing synchrotron photon energy, and indicate a dependency of the upper electronic state specific dissociation dynamics (e.g., perturbation and coupling associated with a particular state). An unprecedented magnitude in isotope separation was observed for photodissociation at the 105 and 107 nm synchrotron bands and are found to be associated with accidental predissociation of the vibrational states ({nu} = 0 and 1) of the upper electronic state E{sup 1}Π. For each synchrotron band, a large (few hundred per mil) extent of isotopic fractionation was observed and the range of fractionation is a combination of column density and exposure time. A significant temperature …
Date: January 3, 2012
Creator: Chakraborty, Subrata; Davis, Ryan; Ahmed, Musahid; Jackson, Teresa L. & Thiemens, Mark H.
Object Type: Article
System: The UNT Digital Library
Characterization of Nb3Sn Strand for ITER (open access)

Characterization of Nb3Sn Strand for ITER

We have an ongoing research program for characterization of superconductor composite strands, the principal output of which is sensitive measurements of critical current Ic over a broad range of the essential parameters: longitudinal strain ε, temperature T, and magnetic field B. This features a new apparatus for integrated measurement of Ic(ε,T,B) on the same, long-conductor sample without remounting.
Date: May 3, 2012
Creator: Cheggour, Najib & Goodrich, Loren F.
Object Type: Report
System: The UNT Digital Library
500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application (open access)

500 MW X-Band RF System of a 0.25 GeV Electron LINAC for Advanced Compton Scattering Source Application

A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with the SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.5 msec pulses, will be the main high power RF sources for the system. These klystrons will be powered by state of the art solid-state high voltage modulators. A RF pulse compressor, similar to the SLED II pulse compressor, will compress the klystron output pulse with a power gain factor of five. For compactness consideration, we are looking at a folded waveguide setup. This will give us 500 MW at output of the compressor. The compressed pulse will then be distributed to the RF gun and to six traveling wave accelerator sections. Phase and amplitude control are located at the RF gun input and additional control points along the LINAC to allow for parameter control during operation. This …
Date: July 3, 2012
Creator: Chu, Tak Sum; Anderson, Scott; Barty, Christopher; Gibson, David; Hartemann, Fred; Marsh, Roark et al.
Object Type: Article
System: The UNT Digital Library
Photoluminescence of Diamondoid Crystals (open access)

Photoluminescence of Diamondoid Crystals

The photoluminescence of diamondoids in the solid state is examined. All of the diamondoids are found to photoluminesce readily with initial excitation wavelengths ranging from 233 nm to 240 nm (5.3 eV). These excitation energies are more than 1 eV lower than any previously studied saturated hydrocarbon material. The emission is found to be heavily shifted from the absorption, with emission wavelengths of roughly 295 nm (4.2 eV) in all cases. In the dissolved state, however, no uorescence is observed for excitation wavelengths as short as 200 nm. We also discuss predictions and measurements of the quantum yield. Our predictions indicate that the maximum yield may be as high as 25%. Our measurement of one species, diamantane, gives a yield of 11%, the highest ever reported for a saturated hydrocarbon, even though it was likely not at the optimal excitation wavelength.
Date: April 3, 2012
Creator: Clay, William; /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept. /Stanford U., Geballe Lab.; Sasagawa, Takao; Iwasa, Akio; /TIT, Nagatsuta; Liu, Zhi et al.
Object Type: Article
System: The UNT Digital Library
Design and Development of New Carbon-Based Sorbent Systems for an Effective Containment of Hydrogen (open access)

Design and Development of New Carbon-Based Sorbent Systems for an Effective Containment of Hydrogen

This is a summary for work performed under cooperative agreement DE FC36 04GO14006 (Design and Development of New Carbon-based Sorbent Systems for an Effective Containment of Hydrogen). The project was directed to discover new solid and liquid materials that use reversible catalytic hydrogenation as the mechanism for hydrogen capture and storage. After a short period of investigation of solid materials, the inherent advantages of storing and transporting hydrogen using liquid-phase materials focused our attention exclusively on organic liquid hydrogen carriers (liquid carriers). While liquid carriers such as decalin and methylcyclohexane were known in the literature, these carriers suffer from practical disadvantages such as the need for very high temperatures to release hydrogen from the carriers and difficult separation of the carriers from the hydrogen. In this project, we were successful in using the prediction of reaction thermodynamics to discover liquid carriers that operate at temperatures up to 150 C lower than the previously known carriers. The means for modifying the thermodynamics of liquid carriers involved the use of certain molecular structures and incorporation of elements other than carbon into the carrier structure. The temperature decrease due to the more favorable reaction thermodynamics results in less energy input to release hydrogen …
Date: May 3, 2012
Creator: Cooper, Alan C.
Object Type: Report
System: The UNT Digital Library