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Organic-Based ("Excitonic") Solar Cells

Description: The existing types of organic-based solar cells, including dye-sensitized solar cells (DSSCs), can be categorized by their photoconversion mechanism as excitonic solar cells, XSCs. Their distinguishing characteristic is that charge generation and separation are simultaneous and this occurs via exciton dissociation at a heterointerface. Electrons are photogenerated on one side of the interface and holes on the other. This results in fundamental differences between XSCs and conventional PV cells. For example, the open circuit photovoltage, Voc, in conventional cells is limited to less than the magnitude of the band bending, bi; however, Voc in XSCs is commonly greater than bi. A general theoretical description is employed to quantify the differences between conventional and excitonic cells. The key difference is the dominant importance, in XSCs, of the photoinduced chemical potential energy gradient, ..delta..hn, whereas ..delta..hn is unimportant, and therefore neglected, in theoretical descriptions of conventional PV cells. Several examples are provided.
Date: May 1, 2003
Creator: A., Gregg. B.
Partner: UNT Libraries Government Documents Department
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ENGINEERING OF THE AGS SNAKE COIL ASSEMBLY.

Description: A 30% Snake superconducting magnet is proposed to maintain polarization in the AGS proton beam, the magnetic design of which is described elsewhere. The required helical coils for this magnet push the limits of the technology developed for the RHIC Snake coils. First, fields must be provided with differing pitch along the length of the magnet. To accomplish this, a new 3-D CAD system (''Pro/Engineer'' from PTC), which uses parametric techniques to enable fast iterations, has been employed. Revised magnetic field calculations are then based on the output of the mechanical model. Changes are made in turn to the model on the basis of those field calculations. To ensure that accuracy is maintained, the final solid model is imported directly into the CNC machine programming software, rather than by the use of graphics translating software. Next, due to the large coil size and magnetic field, there was concern whether the structure could contain the coil forces. A finite element analysis was performed, using the 3-D model, to ensure that the stresses and deflections were acceptable. Finally, a method was developed using ultrasonic energy to improve conductor placement during coil winding, in an effort to minimize electrical shorts due to conductor misplacement, a problem that occurred in the RHIC helical coil program. Each of these activities represents a significant improvement in technology over that which was used previously for the RHIC snake coils.
Date: May 12, 2003
Creator: ANERELLA,M. GUPTA,R. KOVACH,P. MARONE,A. PLATE,S. POWER,K. SCHMALZLE,J. WILLEN,E.
Partner: UNT Libraries Government Documents Department
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Blade Manufacturing Improvement: Remote Blade Manufacturing Demonstration

Description: The objective of this program was to investigate manufacturing improvements for wind turbine blades. The program included a series of test activities to evaluate the strength, deflection, performance, and loading characteristics of the prototype blades. The original contract was extended in order to continue development of several key blade technologies identified in the project. The objective of the remote build task was to demonstrate the concept of manufacturing wind turbine blades at a temporary manufacturing facility in a rural environment. TPI Composites successfully completed a remote manufacturing demonstration in which four blades were fabricated. The remote demonstration used a manufacturing approach which relied upon material ''kits'' that were organized in the factory and shipped to the site. Manufacturing blades at the wind plant site presents serious logistics difficulties and does not appear to be the best approach. A better method appears to be regional manufacturing facilities, which will eliminate most of the transportation cost, without incurring the logistical problems associated with fabrication directly onsite. With this approach the remote facilities would use commonly available industrial infrastructure such as enclosed workbays, overhead cranes, and paved staging areas. Additional fatigue testing of the M20 root stud design was completed with good results. This design provides adhesive bond strength under fatigue loading that exceeds that of the fastener. A new thru-stud bonding concept was developed for the M30 stud design. This approach offers several manufacturing advantages; however, the test results were inconclusive.
Date: May 1, 2003
Creator: ASHWILL, THOMAS D.
Partner: UNT Libraries Government Documents Department
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Cost Study for Large Wind Turbine Blades

Description: The cost study for large wind turbine blades reviewed three blades of 30 meters, 50 meters, and 70 meters in length. Blade extreme wind design loads were estimated in accordance with IEC Class I recommendations. Structural analyses of three blade sizes were performed at representative spanwise stations assuming a stressed shell design approach and E-glass/vinylester laminate. A bill of materials was prepared for each of the three blade sizes using the laminate requirements prepared during the structural analysis effort. The labor requirements were prepared for twelve major manufacturing tasks. TPI Composites developed a conceptual design of the manufacturing facility for each of the three blade sizes, which was used for determining the cost of labor and overhead (capital equipment and facilities). Each of the three potential manufacturing facilities was sized to provide a constant annual rated power production (MW per year) of the blades it produced. The cost of the production tooling and overland transportation was also estimated. The results indicate that as blades get larger, materials become a greater proportion of total cost, while the percentage of labor cost is decreased. Transportation costs decreased as a percentage of total cost. The study also suggests that blade cost reduction efforts should focus on reducing material cost and lowering manufacturing labor, because cost reductions in those areas will have the strongest impact on overall blade cost.
Date: May 1, 2003
Creator: ASHWILL, THOMAS D.
Partner: UNT Libraries Government Documents Department
open access

DETERMINING THE RATIO OF THE H+ YIELDS TV TO H+ YIELDS TB DECAY RATES FOR LARGE TAN BETA AT THE LARGE HADRON COLLIDER.

Description: We present results on the determination of the observable ratio R = BR(H{sup +} {yields} {tau}{sup +}{nu}{sup -})/BR(H{sup +} {yields} t{bar b}) of charged Higgs boson decay rates as a discriminant quantity between Supersymmetric and non-Supersymmetric models. Simulation of measurements of this quantity through the analysis of the charged Higgs production process gb {yields} tbH{sup +} and relative backgrounds in the two above decay channels has been performed in the context of ATLAS. A {approx} 12-14% accuracy on R can be achieved for tan {beta} = 50, m{sub H{sup {+-}}} = 300-500 GeV and after an integrated luminosity of 300 fb{sup -1}. With this precision measurement, the Large Hadron Collider (LHC) can easily discriminate between models for the two above scenarios, so long as tan {beta} > 20.
Date: May 27, 2003
Creator: ASSAMAGAN,K. A. GUASCH,J. MORETTI,S. PENARANDA,S.
Partner: UNT Libraries Government Documents Department
open access

Charged Higgs bosons in the transition region M{sub H{sup {+-}}} {approx} m{sub t} at the LHC

Description: We illustrate preliminary results obtained through Monte Carlo (HERWIG) and detector (ATLFAST) simulations of the H{sup {+-}} {yields} {tau}{sup {+-}}{nu}{sub {tau}} signature of charged Higgs bosons with masses comparable to that of the top quark.
Date: May 25, 2003
Creator: ASSAMAGAN,K. A. GUCHAIT,M. MORETTI,S.
Partner: UNT Libraries Government Documents Department
open access

Laser Safety Audit and Inventory System Database

Description: A laser safety auditing and inventory system has been in use at Sandia National Laboratories--Albuquerque for the past five years and has recently been considered for adoption by Sandia National Laboratories--Livermore. The system utilizes the ''Microsoft Access'' database application, part of the Office 2000 software package. Audit and inventory data is available on-line for ready access by laser users. Data is updated weekly to provide users with current information relating to laser facility audits and laser inventories.
Date: May 1, 2003
Creator: AUGUSTONI, ARNOLD L.
Partner: UNT Libraries Government Documents Department
open access

Electricity: The Road Toward Restructuring

Description: The Public Utility Holding Company Act of 1935 (PUHCA) and the Federal Power Act (FPA) were enacted to eliminate unfair practices and other abuses by electricity and gas holding companies by requiring federal control and regulation of interstate public utility holding companies. Comprehensive energy legislation has passed the House and Senate. The House passed H.R. 6 on April 11, 2003. On July 31, 2003, the Senate suspended debate on S. 14, inserted the text of H.R. 4 (107th Congress) as a substitute, and passed H.R. 6. A conference agreement was reached November 17, 2003, and passed by the House the next day. H.R. 6 includes an electricity title that would, in part, repeal PUHCA, would prospectively repeal the mandatory purchase requirement under PURPA, and would create an electric reliability organization. On June 15, 2004, H.R. 4503, a comprehensive energy policy bill, passed the House.
Date: May 2, 2003
Creator: Abel, Amy & Parker, Larry
Partner: UNT Libraries Government Documents Department
open access

Electricity: The Road Toward Restructuring

Description: The Public Utility Holding Company Act of 1935 (PUHCA) and the Federal Power Act (FPA) were enacted to eliminate unfair practices and other abuses by electricity and gas holding companies by requiring federal control and regulation of interstate public utility holding companies. Comprehensive energy legislation has passed the House and Senate. The House passed H.R. 6 on April 11, 2003. On July 31, 2003, the Senate suspended debate on S. 14, inserted the text of H.R. 4 (107th Congress) as a substitute, and passed H.R. 6. A conference agreement was reached November 17, 2003, and passed by the House the next day. H.R. 6 includes an electricity title that would, in part, repeal PUHCA, would prospectively repeal the mandatory purchase requirement under PURPA, and would create an electric reliability organization. On June 15, 2004, H.R. 4503, a comprehensive energy policy bill, passed the House.
Date: May 13, 2003
Creator: Abel, Amy & Parker, Larry
Partner: UNT Libraries Government Documents Department
open access

Education Vouchers: Constitutional Issues and Cases

Description: This report details the constitutional standards that currently apply to indirect school aid programs and summarizes all of the pertinent Supreme Court decisions, with particular attention to Zelman. It also summarizes the pending case of Davey v. Locke and other recent and ongoing state and lower federal court cases concerning vouchers.
Date: May 20, 2003
Creator: Ackerman, David M.
Partner: UNT Libraries Government Documents Department
open access

Deployment of a Continuously Operated {mu}ChemLab

Description: A continuously operating prototype chemical weapons sensor system based on the {mu}ChemLab{trademark} technology was installed in the San Francisco International Airport in late June 2002. This prototype was assembled in a National Electric Manufacturers Association (NEMA) enclosure and controlled by a personal computer collocated with it. Data from the prototype was downloaded regularly and periodic calibration tests were performed through modem-operated control. The instrument was installed just downstream of the return air fans in the return air plenum of a high-use area of a boarding area. A CW Sentry, manufactured by Microsensor Systems, was installed alongside the {mu}ChemLab unit and results from its operation are reported elsewhere. Tests began on June 26, 2002 and concluded on October 16, 2002. This report will discuss the performance of the prototype during the continuous testing period. Over 70,000 test cycles were performed during this period. Data from this first field emplacement have indicated several areas where engineering improvements can be made for future field emplacement.
Date: May 1, 2003
Creator: Adkins, Douglas R.; Kottenstette, Richard; Lewis, Patrick R.; Dulleck, George R., Jr.; Oborny, Michael C.; Gordon, Susanna P. et al.
Partner: UNT Libraries Government Documents Department
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Evaluating the Effects of Tri-Butyl Phosphate and Normal Paraffin Hydrocarbon in Simulated Low-Activity Waste Solution on Ion Exchange

Description: Ultrafiltration and ion exchange are among the pretreatment processes selected for the WTP at the Hanford Site. This study is the second part of a two-part study on Evaluating the Effects of Tri-Butyl Phosphate and Normal Paraffin Hydrocarbon in Simulated Low-Activity Waste Solution on Ultrafiltration and Ion Exchange.
Date: May 13, 2003
Creator: Adu-Wusu, K.
Partner: UNT Libraries Government Documents Department
open access

Linear and Nonlinear Wave Propagation in Negative Refraction Meta-materials

Description: We discuss linear and nonlinear optical wave propagation in a left-handed medium (LHM) or medium of negative refraction (NRM). We use the approach of characterizing the medium response totally by a generalized electric polarization (with a dielectric permittivity {tilde {var_epsilon}}(w, {rvec k})) that can be decomposed into a curl and a non-curl part. The description has a one-to-one correspondence with the usual approach characterizing the LHM response with a dielectric permittivity {var_epsilon}<0 and a magnetic permeability {mu}<0. The latter approach is less physically transparent in the optical frequency region because the usual definition of magnetization loses its physical meaning. Linear wave propagation in LHM or NRM is characterized by negative refraction and negative group velocity that could be clearly manifested by ultra-short pulse propagation in such a medium. Nonlinear optical effects in LHM can be predicted from the same calculations adopted for ordinary media using our general approach.
Date: May 29, 2003
Creator: Agranovich, V.M.; Shen, Y.R.; Baughman, R.H. & Zakhidov, A.A.
Partner: UNT Libraries Government Documents Department
open access

U.S. - European Union Disputes in the World Trade Organization

Description: This report discusses disputes in the World Trade Organization (WTO) between the United States and the European Union (EU). The report begins with an overview of the issues to be addressed, and continues with a brief description of the WTO dispute settlement process, a summary of U.S.-EU dispute settlement history, and a review of issues arising from cases of longstanding non-compliance. The report concludes with a discussion of continuing concerns and policy considerations.
Date: May 27, 2003
Creator: Ahearn, Raymond J. & Grimmett, Jeanne J.
Partner: UNT Libraries Government Documents Department
open access

Performing Neutron Cross-Section Measurements at RIA

Description: The Rare Isotope Accelerator (RIA) is a proposed accelerator for the low energy nuclear physics community. Its goal is to understand the natural abundances of the elements heavier than iron, explore the nuclear force in systems far from stability, and study symmetry violation and fundamental physics in nuclei. To achieve these scientific goals, RIA promises to produce isotopes far from stability in sufficient quantities to allow experiments. It would also produce near stability isotopes at never before seen production rates, as much as 10{sup 12} pps. Included in these isotopes are many that are important to stockpile stewardship, such as {sup 87}Y, {sup 146-50}Eu, and {sup 231}Th. Given the expected production rates at RIA and a reasonably intense neutron source, one can expect to make {approx} 10 {micro}g targets of nuclei with a half-life of {approx}1 day. Thus, it will be possible at RIA to obtain experimental information on the neutron cross section for isotopes that have to date only been determined by theory. There are two methods to perform neutron cross-section measurements, prompt and delayed. The prompt method tries to measure each reaction as it happens. The exact technique employed will depend on the reaction of interest, (n,2n), (n,{gamma}), (n,p), etc. The biggest challenge with this method is designing a detector system that can handle the gamma ray background from the target. The delayed method, which is the traditional radiochemistry method for determining the cross-section, irradiates the targets and then counts the reaction products after the fact. While this allows one to avoid the target background, the allowed fraction of target impurities is extremely low. This is especially true for the desired reaction product with the required impurity fraction on the order of 10{sup -9}. This is particularly problematic for (n,2n) and (n,{gamma}) reactions, whose reaction production cannot be …
Date: May 20, 2003
Creator: Ahle, L. E.
Partner: UNT Libraries Government Documents Department
open access

A Neutron Source Facility for Neutron Cross-Section Measurements on Radioactive Targets at RIA

Description: The stockpile stewardship program is interested in neutron cross-section measurements on nuclei that are a few nucleons away from stability. Since neutron targets do not exist, radioactive targets are the only way to directly perform these measurements. This requires a facility that can provide high production rates for these short-lived nuclei as well as a source of neutrons. The Rare Isotope Accelerator (RIA) promises theses high production rates. Thus, adding a co-located neutron source facility to the RIA project baseline would allow these neutron cross-section measurements to be made. A conceptual design for such a neutron source has been developed, which would use two accelerators, a Dynamitron and a linac, to create the neutrons through a variety of reactions (d-d, d-t, deuteron break-up, p-Li). This range of reactions is needed in order to provide the desired energy range from 10's of keV to 20 MeV. The facility would also have hot cells to perform chemistry on the radioactive material both before and after neutron irradiation. The present status of this design and direction of future work will be discussed.
Date: May 20, 2003
Creator: Ahle, L. E.; Bernstein, L.; Rusnak, B. & Berio, R.
Partner: UNT Libraries Government Documents Department
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Development and testing of a method for efficient simulation of evaporation from a seepage face

Description: Evaporation from the surface of a porous medium is a complex process, governed by interplay between (1) coupled liquid and vapor flow in the porous medium, and (2) relative humidity, temperature, and aerodynamic conditions in the surrounding air. In order to avoid the computational expense of explicitly simulating liquid, gas, and heat flow in the porous medium (and the possible further expense of simulating the flow of water vapor in the atmosphere), evaporative potentials can be treated in a simplified manner within a model where liquid is the only active phase. In the case of limited air mixing, evaporation can be approximated as a diffusion process with a linear vapor-concentration gradient. We have incorporated a simplified scheme into the EOS9 module of iTOUGH2 to represent evaporation as isothermal Fickian diffusion. This is notable because the EOS9 module solves a single equation describing saturated and unsaturated flow, i.e., phase transitions and vapor flow are not explicitly simulated. The new approach was applied to three simple problems and the results were compared to those obtained with analytical solutions or the EOS4 module, which explicitly considers advective and diffusive vapor flow. Where vapor flow within the porous medium can be neglected, this new scheme represents significant improvement over the computational expense of explicitly simulating liquid, gas, and heat flow, while providing an adequate reproduction of the overall hydrologic system. The scheme is set up to allow parallel flow of liquid and vapor, so that evaporation from an actively seeping face can be simulated. In addition, dynamic relative humidity boundary conditions can be simulated using standard iTOUGH2 features.
Date: May 12, 2003
Creator: Ahlers, C. Fredrik; Ghezzehei, Teamrat & Finsterle, Stefan
Partner: UNT Libraries Government Documents Department
open access

Journey for Jazz

Description: This written thesis accompanies a 32-minute documentary video, Journey for Jazz, which explores four Korean students who major in jazz at the University of North Texas in Denton. Detailed accounts of the pre-production, production, and post-production of the video guide the reader to understand the challenging and rewarding process of making this documentary. Theoretical issues are also discussed, including Bill Nichols's typology of documentary modes as a useful tool for analysis of hybrid documentaries and conventions of the observational and interactive mode in Journey for Jazz, which is considered a hybrid of both modes. The film focuses mainly on the scholarly and artistic experiences that the four students undergo while studying jazz in the United States.
Date: May 2003
Creator: Ahn, Byungkyu
Partner: UNT Libraries
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The RHIC Injector Accelerators Configurations, and Performance for the RHIC 2003 Au-D Physics Run.

Description: The RHIC 2003 Physics Run [1] required collisions between gold ions and deuterons. The injector necessarily had to deliver adequate quality (transverse and longitudinal emittance) and quantity of both species. For gold this was a continuing evolution from past work [2]. For deuterons it was new territory. For the filling of the RHIC the injector not only had to deliver quality beams but also had to switch between these species quickly. This paper details the collider requirements and our success in meeting these. Some details of the configurations employed are given.
Date: May 12, 2003
Creator: Ahrens, L.; Benjamin, J.; Blaskiewicz, M.; Brennan, J. M.; Brown, K. A.; Carlson, K. A. et al.
Partner: UNT Libraries Government Documents Department
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Review of Test Facilities for Distributed Energy Resources

Description: Since initiating research on integration of distributed energy resources (DER) in 1999, the Consortium for Electric Reliability Technology Solutions (CERTS) has been actively assessing and reviewing existing DER test facilities for possible demonstrations of advanced DER system integration concepts. This report is a compendium of information collected by the CERTS team on DER test facilities during this period.
Date: May 1, 2003
Creator: Akhil, Abbas Ali; Marnay, Chris & Kipman, Timothy
Partner: UNT Libraries Government Documents Department
open access

The Russian trumpet sonata: a study of selected representative sonatas for trumpet and piano with an historical overview of the Russian trumpet school

Description: The impact of training on virtual team effectiveness was assessed in five areas: communication, planning tasks and setting goals, solving problems and making decisions, resolving conflict, and responding to customer requirements. A 12-page survey was developed exploring all aspects of virtual teams. 180 surveys were distributed, 52 were returned representing 43 companies. Training led to higher effectiveness in planning tasks and setting goals, solving problems and making decisions, and conflict resolution, but not in communication and responding to customer requirements. Training may not solve all the problems that virtual teams will encounter; however, training will make the challenges easier to handle.
Date: May 2003
Creator: Akhmadullin, Iskander
Partner: UNT Libraries
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