Degree Department

Degree Level

2,655 Matching Results

Results open in a new window/tab.

A Survey of the U.S. ESCO Industry: Market Growth and Developmentfrom 2000 to 2006 (open access)

A Survey of the U.S. ESCO Industry: Market Growth and Developmentfrom 2000 to 2006

None
Date: May 1, 2007
Creator: Hopper, Nicole; Goldman, Charles; Gilligan, Donald; Singer, TerryE. & Birr, Dave
Object Type: Report
System: The UNT Digital Library
Final Report on Control Algorithm to Improve the Partial-Load Efficiency of Surface PM Machines with Fractional-Slot Concentrated Windings (open access)

Final Report on Control Algorithm to Improve the Partial-Load Efficiency of Surface PM Machines with Fractional-Slot Concentrated Windings

Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque amplitudes as well as significantly increasing the machine power density [3-5] compared to SPM machines using conventional distributed windings. High efficiency can be achieved in this class of SPM machine by making special efforts to suppress the eddy-current losses in the magnets [6-8], accompanied by efforts to minimize the iron losses in the rotor and stator cores. Considerable attention has traditionally been devoted to maximizing the full-load efficiency of traction machines at their rated operating points and along their maximum-power vs. speed envelopes for higher speeds [9,10]. For example, on-line control approaches have been presented for maximizing the full-load efficiency of PM synchronous machines, including the use of negative d-axis stator current to reduce the core losses [11,12]. However, another important performance specification for electric traction applications is the machine's efficiency at partial loads. Partial-load efficiency is particularly important if …
Date: May 1, 2007
Creator: McKeever, John W; Reddy, Patel & Jahns, Thomas M
Object Type: Report
System: The UNT Digital Library
High Penetration, Grid Connected Photovoltaic Technology Codes and Standards: Preprint (open access)

High Penetration, Grid Connected Photovoltaic Technology Codes and Standards: Preprint

This paper reports the interim status in identifying and reviewing photovoltaic (PV) codes and standards (C&S) and related electrical activities for grid-connected, high-penetration PV systems with a focus on U.S. electric utility distribution grid interconnection.
Date: May 1, 2008
Creator: Basso, T. S.
Object Type: Article
System: The UNT Digital Library
Use of microphysical relationships to discern growth/decay mechanisms of cloud droplets with focus on Z-LWC relationships. (open access)

Use of microphysical relationships to discern growth/decay mechanisms of cloud droplets with focus on Z-LWC relationships.

Cloud droplet size distributions hence the key microphysical quantities (e.g., radar reflectivity, droplet concentration, liquid water content, relative dispersion, and mean-volume radius) are determined by different physical mechanisms, including pre-cloud aerosols as CCNs, cloud updraft, and various turbulent entrainment-mixing processes. Therefore, different relationships among these microphysical properties are expected in response to these various mechanisms. The effect of turbulent entrainment-mixing processes is particularly vexing, with different entrainment-mixing processes likely leading to different microphysical relationships. Cloud radar has been widely used to infer the cloud liquid water content (L) from the measurement of radar reflectivity (Z) using a Z-L relationship. Existing Z-L expressions have been often obtained empirically, and differ substantially (Khain et al. 2008). The discrepancy among Z-L relations, which has been hindering the application of cloud radar in measuring cloud properties, likely stems from the different relationships between the relevant microphysical properties caused by different physical processes. This study first analyzes the Z-L relationship theoretically, and identify the key microphysical properties that affect this relationship, and then address the effects of various processes on the Z-L relationship by discerning the characteristics of the relationships between the relative dispersion, droplet concentration, liquid water content, and mean-volume radius calculated from in-situ …
Date: May 1, 2008
Creator: Liu, Y.; Daum, P. H.; Yum, S. S. & Wang, J.
Object Type: Article
System: The UNT Digital Library

Accelerated UV Test Methods for Encapsulants of Photovoltaic Modules

None
Date: May 1, 2008
Creator: Kempe, M. D.
Object Type: Presentation
System: The UNT Digital Library
Presto user's guide 2.7 (version 1). (open access)

Presto user's guide 2.7 (version 1).

None
Date: May 1, 2007
Creator: Gullerud, Arne S.; Hales, Jason Dean; Koteras, James Richard; Reinert, Rhonda K. & Crane, Nathan Karl
Object Type: Report
System: The UNT Digital Library
ACRF Instrumentation Status: New, Current, and Future - May 2008 (open access)

ACRF Instrumentation Status: New, Current, and Future - May 2008

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: May 1, 2008
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Where do fossil fuel carbon dioxide emissions from California go? An analysis based on radiocarbon observations and an atmospheric transport model (open access)

Where do fossil fuel carbon dioxide emissions from California go? An analysis based on radiocarbon observations and an atmospheric transport model

Characterizing flow patterns and mixing of fossil fuel-derived CO{sub 2} is important for effectively using atmospheric measurements to constrain emissions inventories. Here we used measurements and a model of atmospheric radiocarbon ({sup 14}C) to investigate the distribution and fluxes of atmospheric fossil fuel CO{sub 2} across the state of California. We sampled {sup 14}C in annual C{sub 3} grasses at 128 sites and used these measurements to test a regional model that simulated anthropogenic and ecosystem CO{sub 2} fluxes, transport in the atmosphere, and the resulting {sup 14}C of annual grasses ({Delta}{sub g}). Average measured {Delta}{sub g} in Los Angeles, San Francisco, the Central Valley, and the North Coast were 27.7 {+-} 20.0, 44.0 {+-} 10.9, 48.7 {+-} 1.9, and 59.9 {+-} 2.5{per_thousand}, respectively, during the 2004-2005 growing season. Model predictions reproduced regional patterns reasonably well, with estimates of 27.6 {+-} 2.4, 39.4 {+-} 3.9, 46.8 {+-} 3.0, and 59.3 {+-} 0.2{per_thousand} for these same regions and corresponding to fossil fuel CO{sub 2} mixing ratios (Cf) of 13.7, 6.1, 4.8, and 0.3 ppm. {Delta}{sub g} spatial heterogeneity in Los Angeles and San Francisco was higher in the measurements than in the predictions, probably from insufficient spatial resolution in the fossil …
Date: May 1, 2008
Creator: Riley, W. J.; Hsueh, D. Y.; Randerson, J. T.; Fischer, M. L.; Hatch, J. G.; Pataki, D. E. et al.
Object Type: Article
System: The UNT Digital Library
Completion Report for Well ER-12-4, Corrective Action Unit 99: Rainier Mesa - Shoshone Mountain (includes Errata Sheet) (open access)

Completion Report for Well ER-12-4, Corrective Action Unit 99: Rainier Mesa - Shoshone Mountain (includes Errata Sheet)

Well ER-12-4 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This well was drilled in May 2005, as part of a hydrogeologic investigation program for the Rainier Mesa-Shoshone Mountain Corrective Action Unit in the north-central portion of the Nevada Test Site. The well is located on Rainier/Aqueduct Mesa, northwest of Yucca Flat, within Area 12 of the Nevada Test Site. The well provided information regarding the radiological and physical environment near underground nuclear tests conducted in U12t Tunnel, information on the pre-Tertiary rocks in the area, and depth to the regional water table.
Date: May 1, 2006
Creator: United States. National Nuclear Security Administration. Nevada Site Office.
Object Type: Report
System: The UNT Digital Library
Habitat Evaluation Procedures (HEP) Report : Ladd Marsh Wildlife Area, 2004-2006 Technical Report. (open access)

Habitat Evaluation Procedures (HEP) Report : Ladd Marsh Wildlife Area, 2004-2006 Technical Report.

The Regional HEP Team (RHT) and Oregon Department of Fish and Wildlife (ODFW) staff conducted a follow-up habitat evaluation procedures (HEP) analysis on the Ladd Marsh Wildlife Management Area (LMWA) in May 2005. The 2005 HEP assessment resulted in a total of 647.44 HUs, or 0.76 HUs/acre. This is an increase of 420.34 HUs (0.49 HUs/acre) over 2001 HEP survey results. The most significant increase in HUs occurred on the Wallender and Simonis parcels which increased by 214.30 HUs and 177.49 HUs respectively. Transects were established at or near 2001 HEP analysis transect locations whenever possible. ODFW staff biologists assisted the RHT re-establish transect locations and/or suggested areas for new surveys. Since 2001, significant changes in cover type acreage and/or structural conditions have occurred due to conversion of agriculture cover types to emergent wetland and grassland cover types. Agricultural lands were seeded to reestablish grasslands and wetlands were restored through active management and manipulation of extant water sources including natural stream hydrology/flood regimes and available irrigation. Grasslands increased on the Wallender parcel by 21% (65 acres), 23% (71 acres) at the Simonis site, and 39% (62 acres) at Conley Lake. The emergent wetland cover type also changed significantly increasing 60% …
Date: May 1, 2006
Creator: Ashley, Paul & Wagoner, Sara
Object Type: Report
System: The UNT Digital Library

Intrinsic DX Centers in Ternary Chalcopyrite Semiconductors

The conclusions of this report are: (1) intrinsic donor-type defects In{sub Cu}, Ga{sub Cu}, and V{sub Se}, and their complexes with V{sub Cu} cause metastability, but also act to limit V{sub OC}; (2) growth conditions which minimize these defects (Cu-rich/Se-rich) are very different from those currently used; and (3) overcoming V{sub OC} limitation requires to address other issues and trade-offs.
Date: May 1, 2008
Creator: Lany, S. & Zunger, A.
Object Type: Presentation
System: The UNT Digital Library
Loads Providing Ancillary Services: Review of InternationalExperience-- Technical Appendix: Market Descriptions (open access)

Loads Providing Ancillary Services: Review of InternationalExperience-- Technical Appendix: Market Descriptions

In this study, we examine the arrangements for andexperiences of end-use loads providing ancillary services (AS) in fiveelectricity markets: Australia, the United Kingdom (UK), the Nordicmarket, and the ERCOT and PJM markets in the United States. Our objectivein undertaking this review of international experience was to identifyspecific approaches or market designs that have enabled customer loads toeffectively deliver various ancillary services (AS) products. We hopethat this report will contribute to the ongoing discussion in the U.S.and elsewhere regarding what institutional and technical developments areneeded to ensure that customer loads can meaningfully participate in allwholesale electricity markets.
Date: May 1, 2007
Creator: Grayson Heffner, Charles Goldman, Kintner-Meyer, M & Kirby, Brendan
Object Type: Report
System: The UNT Digital Library
Help for the Developers of Control System Cyber Security Standards (open access)

Help for the Developers of Control System Cyber Security Standards

A Catalog of Control Systems Security: Recommendations for Standards Developers (Catalog), aimed at assisting organizations to facilitate the development and implementation of control system cyber security standards, has been developed. This catalog contains requirements that can help protect control systems from cyber attacks and can be applied to the Critical Infrastructures and Key Resources of the United States and other nations. The requirements contained in the catalog are a compilation of practices or various industry bodies used to increase the security of control systems from both physical and cyber attacks. They should be viewed as a collection of recommendations to be considered and judiciously employed, as appropriate, when reviewing and developing cyber security standards for control systems. The recommendations in the Catalog are intended to be broad enough to provide any industry using control systems the flexibility needed to develop sound cyber security standards specific to their individual security requirements.
Date: May 1, 2008
Creator: Evans, Robert P.
Object Type: Article
System: The UNT Digital Library
Silicon Solar Cells with Front Hetero-contact and Aluminum Alloy Back Junction (Poster) (open access)

Silicon Solar Cells with Front Hetero-contact and Aluminum Alloy Back Junction (Poster)

The objectives of this report are: (1) to apply industrial back Al process in efficient n-wafer cells with a-Si:H front surface passivation; and (2) to evaluate the surface recombination velocity (SRV) of the a-Si:H passivated front surface with different surface preparation procedures.
Date: May 1, 2008
Creator: Yuan, H.-C.; Page, M. R.; Iwaniczko, E.; Xu, Y.; Roybal, L.; Wang, Q. et al.
Object Type: Article
System: The UNT Digital Library
RHIC RF Harmonic Numbers for Low Energy Operations (open access)

RHIC RF Harmonic Numbers for Low Energy Operations

There have been several test runs of RHIC operations to explore the feasibility of luminosity production at low energies. There is considerable international interest in the possible existence of a QCD phase diagram critical point in the RHIC gold-gold collision energy range of {radical}s{sub NN} = 5-50 GeV[l, 2, 3]. This paper reviews the RF harmonic number constraints for RHIC gold-gold collisions in this energy range, and concludes that optimal simultaneous collisions at both experiments are only feasible when the harmonic number is divisible by 9.
Date: May 1, 2008
Creator: Satogata, T.
Object Type: Report
System: The UNT Digital Library
U.S. Department of Energy Wind and Hydropower Technologies: Top 10 Program Accomplishments (open access)

U.S. Department of Energy Wind and Hydropower Technologies: Top 10 Program Accomplishments

This brochure describes the top ten accompishments of the DOE Wind Energy Program during the past 30 years.
Date: May 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
WIPP Gas-Generation Experiments (open access)

WIPP Gas-Generation Experiments

An experimental investigation was conducted for gas generation in contact-handled transuranic (CH TRU) wastes subjected for several years to conditions similar to those expected to occur at the Waste Isolation Pilot Plant (WIPP) should the repository eventually become inundated with brine. Various types of actual CH TRU wastes were placed into 12 corrosion-resistant vessels. The vessels were loosely filled with the wastes, which were submerged in synthetic brine having the same chemical composition as that in the WIPP vicinity. The vessels were also inoculated with microbes found in the Salado Formation at WIPP. The vessels were sealed, purged, and the approximately 750 ml headspace in each vessel was pressurized with nitrogen gas to approximately 146 atmospheres to create anoxic conditions at the lithostatic pressure estimated in the repository were it to be inundated. The temperature was maintained at the expected 30°C. The test program objective was to measure the quantities and species of gases generated by metal corrosion, radiolysis, and microbial activity. These data will assist in the specification of the rates at which gases are produced under inundated repository conditions for use in the WIPP Performance Assessment computer models. These experiments were very carefully designed, constructed, instrumented, and performed. …
Date: May 1, 2007
Creator: Felicione, Frank S.; Frank, Steven M. & Keiser, Dennis D.
Object Type: Report
System: The UNT Digital Library
Effects of Temporal Wind Patterns on the Value of Wind-Generated Electricity in California and the Northwest (open access)

Effects of Temporal Wind Patterns on the Value of Wind-Generated Electricity in California and the Northwest

Wind power production is variable, but also has diurnal and seasonal patterns. These patterns differ between sites, potentially making electric power from some wind sites more valuable for meeting customer loads or selling in wholesale power markets. This paper investigates whether the timing of wind significantly affects the value of electricity from sites in California and the Northwestern United States. We use both measured and modeled wind data and estimate the time-varying value of wind power with both financial and load-based metrics. We find that the potential difference in wholesale market value between better-correlated and poorly correlated wind sites is modest, on the order of 5-10 percent. A load-based metric, power production during the top 10 percent of peak load hours, varies more strongly between sites, suggesting that the capacity value of different wind projects could vary by as much as 50 percent based on the timing of wind alone.
Date: May 1, 2008
Creator: Wiser, Ryan H; Wiser, Ryan H & Fripp, Matthias
Object Type: Article
System: The UNT Digital Library

Design of Shallow p-type Dopants in ZnO

ZnO is a promising material for short wave-length opto-electronic devices such as UV lasers and LEDs due to its large exciton binding energy and low material cost. ZnO can be doped easily n-type, but the realization of stable p-type ZnO is rather difficult. Using first-principles band structure methods the authors address what causes the p-type doping difficulty in ZnO and how to overcome the p-type doping difficulty in ZnO.
Date: May 1, 2008
Creator: Wei, S.H.; Li, J. & Y., Yan.
Object Type: Presentation
System: The UNT Digital Library
Final Work Plan for Targeted Sampling at Webber, Kansas. (open access)

Final Work Plan for Targeted Sampling at Webber, Kansas.

This Work Plan outlines the scope of work for targeted sampling at Webber, Kansas (Figure 1.1). This activity is being conducted at the request of the Kansas Department of Health and Environment (KDHE), in accordance with Section V of the Intergovernmental Agreement between the KDHE and the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA). Data obtained in this sampling event will be used to (1) evaluate the current status of previously detected contamination at Webber and (2) determine whether the site requires further action. This work is being performed on behalf of the CCC/USDA by the Environmental Science Division of Argonne National Laboratory. Argonne is a nonprofit, multidisciplinary research center operated by the University of Chicago for the U.S. Department of Energy (DOE). The CCC/USDA has entered into an interagency agreement with DOE, under which Argonne provides technical assistance to the CCC/USDA with environmental site characterization and remediation at its former grain storage facilities. Argonne has issued a Master Work Plan (Argonne 2002) that describes the general scope of and guidance for all investigations at former CCC/USDA facilities in Kansas. The Master Work Plan, approved by the KDHE, contains the materials common to investigations at all locations …
Date: May 1, 2006
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Corrective Action Decision Document/Closure Report for Corrective Action Unit 234: Mud Pits, Cellars, and Mud Spills Nevada Test Site, Nevada, Revision 0 (open access)

Corrective Action Decision Document/Closure Report for Corrective Action Unit 234: Mud Pits, Cellars, and Mud Spills Nevada Test Site, Nevada, Revision 0

This Corrective Action Decision Document/Closure Report has been prepared for Corrective Action Unit (CAU) 234, Mud Pits, Cellars, and Mud Spills, located in Areas 2, 3, 4, 12, and 15 at the Nevada Test Site, Nevada, in accordance with the Federal Facility Agreement and Consent Order (FFACO, 1996; as amended February 2008). Corrective Action Unit 234 is comprised of the following 12 corrective action sites: •02-09-48, Area 2 Mud Plant #1 •02-09-49, Area 2 Mud Plant #2 •02-99-05, Mud Spill •03-09-02, Mud Dump Trenches •04-44-02, Mud Spill •04-99-02, Mud Spill •12-09-01, Mud Pit •12-09-04, Mud Pit •12-09-08, Mud Pit •12-30-14, Cellar •12-99-07, Mud Dump •15-09-01, Mud Pit The purpose of this Corrective Action Decision Document/Closure Report is to provide justification and documentation supporting the recommendation for closure of CAU 234 with no further corrective action. To achieve this, corrective action investigation (CAI) activities were performed as set forth in the Corrective Action Investigation Plan for Corrective Action Unit 234: Mud Pits, Cellars, and Mud Spills (NNSA/NSO, 2007). The purpose of the CAI was to fulfill the following data needs as defined during the data quality objective (DQO) process: •Determine whether contaminants of concern are present. •If contaminants of concern are …
Date: May 1, 2008
Creator: Evenson, Grant
Object Type: Report
System: The UNT Digital Library
Observation of Disappearance of Muon Neutrinos in the NuMI Beam (open access)

Observation of Disappearance of Muon Neutrinos in the NuMI Beam

The Main Injector Neutrino Oscillation Search (MINOS) is a two detector long-baseline neutrino experiment designed to study the disappearance of muon neutrinos. MINOS will test the {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillation hypothesis and measure precisely {Delta}m{sub 23}{sup 2} and sin{sup 2} 2{theta}{sub 23} oscillation parameters. The source of neutrinos for MINOS experiment is Fermilab's Neutrinos at the Main Injector (NuMI) beamline. The energy spectrum and the composition of the beam is measured at two locations, one close to the source and the other 735 km down-stream in the Soudan Mine Underground Laboratory in northern Minnesota. The precision measurement of the oscillation parameters requires an accurate prediction of the neutrino flux at the Far Detector. This thesis discusses the calculation of the neutrino flux at the Far Detector and its uncertainties. A technique that uses the Near Detector data to constrain the uncertainties in the calculation of the flux is described. The data corresponding to an exposure of 2.5 x 10{sup 20} protons on the NuMI target is presented and an energy dependent disappearance pattern predicted by neutrino oscillation hypotheses is observed in the Far Detector data. The fit to MINOS data, for given exposure, yields the best fit values …
Date: May 1, 2008
Creator: Pavlovic, Zarko
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Evaluation of 2004 Toyota Prius Hybrid Electric Drive System (open access)

Evaluation of 2004 Toyota Prius Hybrid Electric Drive System

The 2004 Toyota Prius is a hybrid automobile equipped with a gasoline engine and a battery- and generator-powered electric motor. Both of these motive-power sources are capable of providing mechanical-drive power for the vehicle. The engine can deliver a peak-power output of 57 kilowatts (kW) at 5000 revolutions per minute (rpm) while the motor can deliver a peak-power output of 50 kW over the speed range of 1200-1540 rpm. Together, this engine-motor combination has a specified peak-power output of 82 kW at a vehicle speed of 85 kilometers per hour (km/h). In operation, the 2004 Prius exhibits superior fuel economy compared to conventionally powered automobiles. To acquire knowledge and thereby improve understanding of the propulsion technology used in the 2004 Prius, a full range of design characterization studies were conducted to evaluate the electrical and mechanical characteristics of the 2004 Prius and its hybrid electric drive system. These characterization studies included (1) a design review, (2) a packaging and fabrication assessment, (3) bench-top electrical tests, (4) back-electromotive force (emf) and locked rotor tests, (5) loss tests, (6) thermal tests at elevated temperatures, and most recently (7) full-design-range performance testing in a controlled laboratory environment. This final test effectively mapped the …
Date: May 1, 2006
Creator: Staunton, Robert H; Ayers, Curtis William; Chiasson, J. N.; Burress, Timothy A & Marlino, Laura D
Object Type: Report
System: The UNT Digital Library
Search for Low Mass SM Higgs at the Tevatron (open access)

Search for Low Mass SM Higgs at the Tevatron

None
Date: May 1, 2008
Creator: Sanders, Michiel P.
Object Type: Article
System: The UNT Digital Library