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Parametric Study for Large Wind Turbine Blades: WindPACT Blade System Design Studies (open access)

Parametric Study for Large Wind Turbine Blades: WindPACT Blade System Design Studies

This report presents the results of a study of various wind turbine blade design parameters as a function of blade length in the range from 30 meters to 70 meters. The results have been summarized in dimensional and non-dimensional formats to aid in interpretation. The parametric review estimated peak power and annual energy capture for megawatt scale wind turbines with rotors of 62, 83, 104, 125, and 146 meters in diameter. The baseline ''thin'' distribution represents conventional airfoils used in large wind turbine blades. The ''thicker'' and ''thickest'' distributions utilize airfoils that have significantly increased thickness to improve structural performance and reduce weight. An aerodynamic scaling effort was undertaken in parallel with the structural analysis work to evaluate the effect of extreme thickness on aerodynamic characteristics. Increased airfoil section thickness appears to be a key tool in limiting blade weight and cost growth with scale. Thickened and truncated trailing edges in the inboard region provide strong, positive effects on blade structural performance. Larger blades may require higher tip speeds combined with reduced blade solidity to limit growth of design loads. A slender blade can be used to reduce extreme design loads when the rotor is parked, but requires a higher …
Date: August 1, 2002
Creator: ASHWILL, THOMAS D.
Object Type: Report
System: The UNT Digital Library
Nucleon Compton Scattering with Two Space-Like Photons (open access)

Nucleon Compton Scattering with Two Space-Like Photons

We calculate two-photon exchange effects for elastic electron-proton scattering at high momentum transfers. The corresponding nucleon Compton amplitude is defined by two space-like virtual photons that appear to have significant virtualities. We make predictions for (a) a single-spin beam asymmetry, and (b) a single-spin target asymmetry or recoil proton polarization caused by an unpolarized electron beam.
Date: August 1, 2002
Creator: Afanasev, Andrei; Akushevich, I. & Merenkov, N.P.
Object Type: Article
System: The UNT Digital Library
Contactless Technique for Measuring Minority-Carrier Parameters in Silicon (open access)

Contactless Technique for Measuring Minority-Carrier Parameters in Silicon

Characterization of minority-carrier parameters is a primary interest for a range of devices, including solar cells. For 'on-line' testing needs, contactless techniques are mandatory, as any diagnostic requiring contact formation is impractical. Here, we will describe the resonance-coupled photoconductive decay (RCPCD) technique that has proven to be a valuable diagnostic for a number of semiconductor technologies. This technique avoids some of the inherent limitations of microwave reflection. Our system is a pump-probe technique, using an optical pump and a microwave probe (400 to 900 MHz). These low frequency microwaves penetrate most silicon wafers with common doping levels. By varying the optical excitation wavelength, one can probe wafers of standard (300 to 400 {micro}m) wafer thickness. Also, the method is very linear in sample photoconductivity, and we have observed a linear response over more than three orders of magnitude of excess carrier concentration. This attribute allows us to measure the carrier recombination lifetime over many decades of injection level, allowing the use of a procedure that is called injection-level spectroscopy (ILS). The RCPCD technique was developed [1,2,3,4,5,6] at the National Renewable Energy Laboratory (NREL) and has been applied to more than 5000 samples, ranging from small-area thin films to 350-{micro}m-thick, 250-mm-diameter …
Date: August 1, 2002
Creator: Ahrenkiel, R. K. & Johnston, S. W.
Object Type: Article
System: The UNT Digital Library
Membership of the 107th Congress: A Profile (open access)

Membership of the 107th Congress: A Profile

None
Date: August 1, 2002
Creator: Amer, Mildred L.
Object Type: Report
System: The UNT Digital Library
Final report (September, 1999--February, 2002) [Public outreach and information dissemination - cellulosic and corn-based ethanol outreach project] (open access)

Final report (September, 1999--February, 2002) [Public outreach and information dissemination - cellulosic and corn-based ethanol outreach project]

EESI's ''Ethanol, Climate Protection, Oil Reduction'' (ECO) electr[on]ic newsletter reaches out to the environmental and agricultural communities, state/local government officials and other interested parties, and provides a forum for dialogue about ''the potential benefits of ethanol--and particularly the expanded opportunities provided by cellulosic ethanol--with a special focus on climate protection.'' Each issue features expert commentary, excerpts from recent studies about ethanol, a summary of current government activity on ethanol, and ''notable quotables.'' The newsletter is distributed primarily via email and is also posted on EESI's web site. EESI also conducts outreach on the benefits of ethanol and other biofuels by attending and speaking at conferences, meetings and workshops around the country. The 16 issues of the newsletter published through December 2001 are included as attachments.
Date: August 1, 2002
Creator: Ames, Jeremy & Werner, Carol
Object Type: Report
System: The UNT Digital Library
Demonstration of the Robotic Gamma Locating and Isotopic Identification Device (open access)

Demonstration of the Robotic Gamma Locating and Isotopic Identification Device

The United States Department of Energy (DOE) continually seeks safer and more cost- effective technologies for use in decontaminating and decommissioning nuclear facilities. To this end, the Deactivation and Decommissioning Focus Area of DOE's Office of Science and Technology sponsors Large-Scale Demonstration and Deployment Projects (LSDDP) to test new technologies. As part of these projects, developers and vendors showcase new products designed to decrease health and safety risks to personnel and the environment, increase productivity, and lower costs. As part of the FY 2000 and 2001 LSDDP, the Idaho National Engineering and Environmental Laboratory (INEEL) collaborated with the Russian Research and Development Institute of Construction Technology (NIKIMT). This collaboration resulted in the development of the Robotic Gamma Locating and Isotopic Identification Device (RGL&IID) which integrated DOE Robotics Crosscutting (Rbx) technology with NIKIMT Russian gamma locating and isotopic identification technology. This paper will discuss the technologies involved in this integration and results from the demonstration including reduction of personnel exposure, increase in productivity, and reduced risk.
Date: August 1, 2002
Creator: Anderson, Matthew Oley; Conner, Craig C; Daniel, Vincent Elvernard; Mckay, Mark D & Yancey, Neal Adam
Object Type: Article
System: The UNT Digital Library
Study of the heavy flavor content of jets produced in W events at the Tevatron collider (open access)

Study of the heavy flavor content of jets produced in W events at the Tevatron collider

We present a detailed study of the heavy flavor content in the W + jet data sample collected with the CDF detector during the 1992-1995 collider run at Fermilab. Rates of heavy flavor jets, identified via the observation of secondary vertices or semileptonic decays of b and c quarks, are in good agreement with a standard model simulation including production of the top quark. An exception is the number of events in which a single jet has both a secondary vertex and a semileptonic decay tag. In the W + 2,3 jet data, we expect 4.4 {+-} 0.6 and we find 13 such events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.
Date: August 1, 2002
Creator: Apollinari, G.
Object Type: Article
System: The UNT Digital Library
ECE Radiometer Upgrade on the DIII-D Tokamak (open access)

ECE Radiometer Upgrade on the DIII-D Tokamak

OAK A271 ECE RADIOMETER UPGRADE ON THE DIII-D TOKAMAK. The electron cyclotron emission (ECE) heterodyne radiometer diagnostic on DIII-D has been upgraded with the addition of eight channels for a total of 40. The new, higher frequency channels allow measurements of electron temperature into the magnetic axis in discharges at maximum field, 2.15 T. The complete set now extends over the full usable range of second harmonic emission frequencies at 2.0 T covering radii from the outer edge inward to the location of third harmonic overlap on the high field side. Full coverage permits the measurement of heat pulses and magnetohydrodynamic (MHD) fluctuations on both sides of the magnetic axis. In addition, the symmetric measurements are used to fix the location of the magnetic axis in tokamak magnetic equilibrium reconstructions. Also, the new higher frequency channels have been used to determine central T{sub e} with good time resolution in low field, high density discharges using third harmonic ECE in the optically gray and optically thick regimes.
Date: August 1, 2002
Creator: Austin, M. E. & Lohr, J.
Object Type: Article
System: The UNT Digital Library
Light Meson Radial Regge Trajectories (open access)

Light Meson Radial Regge Trajectories

A new physical mechanism is suggested to explain the universal depletion of high meson excitations. It takes into account the appearance of holes inside the string world sheet due to q{bar q} pair creation when the length of the string exceeds the critical value R{sub 1} {approx_equal} 1.4 fm. It is argued that a delicate balance between large N{sub c} loop suppression and a favorable gain in the action, produced by holes, creates a new metastable (predecay) stage with a renormalized string tension which now depends on the separation r. This results in smaller values of the slope of the radial Regge trajectories, in good agreement with the analysis of experimental data in references.
Date: August 1, 2002
Creator: Badalian, A. M.; Bakker, B. L. G. & Simonov, Yu. A.
Object Type: Article
System: The UNT Digital Library
A reclusive kind of science (open access)

A reclusive kind of science

This article is a review of Stephen Wolfram's book ''A New Kind of Science''
Date: August 1, 2002
Creator: Bailey, David H.
Object Type: Article
System: The UNT Digital Library
Planning for Site Transition to Long-Term Stewardship: Identification of Requirements and Issues (open access)

Planning for Site Transition to Long-Term Stewardship: Identification of Requirements and Issues

A systematic methodology is presented and applied for the identification of requirements and issues pertaining to the planning for, and transition to, long term stewardship (LTS). The method has been applied to three of the twelve identified LTS functions. The results of the application of the methodology to contaminated and uncontaminated federal real property in those three functions are presented. The issues that could be seen as impediments to the implementation of LTS are also identified for the three areas under consideration. The identified requirements are significant and in some cases complex to implement. It is clear that early and careful planning is required in all circumstances.
Date: August 1, 2002
Creator: Banaee, Jila
Object Type: Article
System: The UNT Digital Library
Source Release Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area (open access)

Source Release Modeling for the Idaho National Engineering and Environmental Laboratory's Subsurface Disposal Area

A source release model was developed to determine the release of contaminants into the shallow subsurface, as part of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) evaluation at the Idaho National Engineering and Environmental Laboratory's (INEEL) Subsurface Disposal Area (SDA). The output of the source release model is used as input to the subsurface transport and biotic uptake models. The model allowed separating the waste into areas that match the actual disposal units. This allows quantitative evaluation of the relative contribution to the total risk and allows evaluation of selective remediation of the disposal units within the SDA.
Date: August 1, 2002
Creator: Becker, Bruce Harley
Object Type: Article
System: The UNT Digital Library
Research on Captive Broodstock Programs for Pacific Salmon, 2001-2002 Annual Report. (open access)

Research on Captive Broodstock Programs for Pacific Salmon, 2001-2002 Annual Report.

The efficacy of captive broodstock programs depends on high in-culture survival and the fitness of cultured salmon after release, either as adults or juveniles. Continuing captive broodstock research designed to improve technology is being conducted to cover all major life history stages of Pacific salmon. The following summarizes some of the work performed and results from the FY 2001 performance period: (1) The incidence of male maturation of age-1 chinook salmon was significantly reduced by reducing growth in the first year of rearing. (2) Experimentally manipulated growth rates of captively-reared coho salmon had significant effects on female maturation rate, egg size, and fecundity, and the effects were stage-specific (i.e., pre-smolt vs. post-smolt). (3) A combination of Renogen and MT239 vaccination of yearling chinook salmon given an acute R. salmoninarum challenge had a significantly longer survival time than the mock-vaccinated group. The survival time was marginally higher than was seen in acutely challenged fish vaccinated with either Renogen or MT239 alone and suggests that a combination vaccine of Renogen and MT239 may be useful as both a prophylactic and therapeutic agent against BKD. (4) Full-sib (inbred) groups of chinook salmon have thus far exhibited lower ocean survival than half-sib and non-related …
Date: August 1, 2002
Creator: Berejikian, Barry; Tezak, E. & Endicott, Rick
Object Type: Report
System: The UNT Digital Library
The Environmental Management Core Laboratories - A Collaborative Effort to Enhance Cleanup (open access)

The Environmental Management Core Laboratories - A Collaborative Effort to Enhance Cleanup

Acknowledging that the magnitude and diversity of the critical issues facing the DOE-EM cannot be addressed by a single institution, the Laboratory Directors established the EM Core Laboratories. This collaborative network ensures that the best available resources are addressing environmental quality issues through the introduction of critical new science and technology. Based upon the Top-to-Bottom Review, the EM program is shifting the focus of its cleanup efforts to accelerate schedules to reduce cost and the most significant risks. To facilitate this acceleration, the Office of Science and Technology has restructured their research and development program towards two new thrusts. These thrusts, Closure Site Support and Alternative Development, are aimed at the high priority needs to support the re-baselined cleanup program. The EM Core Laboratories are well positioned to ensure the successful implementation of this new direction.
Date: August 1, 2002
Creator: Birrer, Steve Allen; Griebenow, Bret Lee; Frandsen, Greg Bryan & Kearns, Paul Kenneth
Object Type: Article
System: The UNT Digital Library
Design of Surface micromachined Compliant MEMS (open access)

Design of Surface micromachined Compliant MEMS

The consideration of compliant mechanisms as Microelectromechanical Systems (MEMS) is the focus of this research endeavor. MEMS are micron to millimeter devices that combine electrical, mechanical, and information processing capabilities on the same device. These MEMS need some mechanical motion or parts that move relative to each other. This relative motion, using multiple parts, is not desired because of the assembly requirement and the friction introduced. Compliant devices limits or eliminates friction and the need for multi-component assembly. Compliant devices improve designs by creating single piece mechanisms. The purpose of this research is to validate surface micromachining as a viable fabrication process for compliant MEMS designs. Specifically, this research has sought to fabricate a micro-compliant gripper and a micro-compliant clamp to illustrate the process. While other researchers have created compliant MEMS, most have used comb-drive actuation methods and bulk micromachining processes. This research focuses on fully-compliant devices that use device flexibility for motion and actuation. Validation of these compliant MEMS is achieved by structural optimization of device design and functional performance testing. This research contributes to the ongoing research in MEMS by evaluating the potential of using surface micromachining as a process for fabricating compliant micro-mechanisms.
Date: August 1, 2002
Creator: Bradley, Joe Anthony
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Production Technology for Passivation of Polycrystalline Silicon Solar Cells (open access)

Production Technology for Passivation of Polycrystalline Silicon Solar Cells

Techniques for cost-efficient operation of SiNx:H systems with a capability for hydrogen passivation in a manufacturing environment are analyzed. We conclude that SiNx:H performance may be optimized by a variety of techniques, and that the cost and productivity of the deposition tool may be the determining factors in the industries decision for a particular technique. PECVD constitutes the current benchmark. Dual magnetron reactive sputtering is a candidate to achieve industry acceptance.
Date: August 1, 2002
Creator: Bragagnolo, J. A.; Sopori, B. & Eser, E.
Object Type: Article
System: The UNT Digital Library
Population Structure of Columbia River Basin Chinook Salmon and Steelhead Trout, Technical Report 2001. (open access)

Population Structure of Columbia River Basin Chinook Salmon and Steelhead Trout, Technical Report 2001.

The population structure of chinook salmon and steelhead trout is presented as an assimilation of the life history forms that have evolved in synchrony with diverse and complex environments over their Pacific range. As poikilotherms, temperature is described as the overwhelming environmental influence that determines what life history options occur and where they are distributed. The different populations represent ecological types referred to as spring-, summer-, fall, and winter-run segments, as well as stream- and ocean-type, or stream- and ocean-maturing life history forms. However, they are more correctly described as a continuum of forms that fall along a temporal cline related to incubation and rearing temperatures that determine spawn timing and juvenile residence patterns. Once new habitats are colonized, members of the founding populations spread through adaptive evolution to assume complementary life history strategies. The related population units are collectively referred to as a metapopulation, and members most closely associated within common temporal and geographic boundaries are designated as first-order metapopulations. Population structure of chinook salmon and steelhead in the Columbia Basin, therefore, is the reflection of the genetic composition of the founding source or sources within the respective region, shaped by the environment, principally temperature, that defines life history …
Date: August 1, 2002
Creator: Brannon, E. L.
Object Type: Report
System: The UNT Digital Library
The Goldthwaite Eagle (Goldthwaite, Tex.), Vol. 107, No. 51, Ed. 1 Thursday, August 1, 2002 (open access)

The Goldthwaite Eagle (Goldthwaite, Tex.), Vol. 107, No. 51, Ed. 1 Thursday, August 1, 2002

Weekly newspaper from Goldthwaite, Texas that includes local, state, and national news along with extensive advertising.
Date: August 1, 2002
Creator: Bridges, G. Frank & Bridges, Georgie
Object Type: Newspaper
System: The Portal to Texas History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 87, No. 275, Ed. 1 Thursday, August 1, 2002 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 87, No. 275, Ed. 1 Thursday, August 1, 2002

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: August 1, 2002
Creator: Broaddus, Matthew B.
Object Type: Newspaper
System: The Gateway to Oklahoma History
Daily Journal (Perry, Okla.), Vol. 109, No. 151, Ed. 1 Thursday, August 1, 2002 (open access)

Daily Journal (Perry, Okla.), Vol. 109, No. 151, Ed. 1 Thursday, August 1, 2002

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: August 1, 2002
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History
Retrack: simulating particle passage through excited resonances (open access)

Retrack: simulating particle passage through excited resonances

N/A
Date: August 1, 2002
Creator: Brown, K. A.
Object Type: Report
System: The UNT Digital Library
Immigration Legislation and Issues in the 107th Congress (open access)

Immigration Legislation and Issues in the 107th Congress

This report briefs the Immigration legislation and issues in the 107th Congress.
Date: August 1, 2002
Creator: Bruno, Andorra; Wasem, Ruth Ellen; Seghetti, Lisa M.; Siskin, Alison & Ester, Karma
Object Type: Report
System: The UNT Digital Library
Single Quark Transition Model Analysis of Electromagnetic Nucleon Resonance Excitations (open access)

Single Quark Transition Model Analysis of Electromagnetic Nucleon Resonance Excitations

We apply the single quark transition model to resonance transition amplitudes extracted from photo- and electroproduction data. We use experimental data on the S{sub 11}(1535), and D{sub 13}(1520) nucleon resonances to extract the amplitudes for the electromagnetic transition from the nucleon ground state [56,0+] to the [70,1-] supermultiplet, and make predictions for the transition amplitudes of all other states associated with the [70,1-]. We compare the predictions with data and find surprisingly good agreement. The comparison is hampered by the poor data quality for many of the states especially in the electroproduction sector.
Date: August 1, 2002
Creator: Burkert, V.D.; Vita, R. De; Battaglieri, M.; Ripani, M. & Mokeev, V.
Object Type: Article
System: The UNT Digital Library
Spin Response of the Nucleon in the Resonance Region (open access)

Spin Response of the Nucleon in the Resonance Region

I discuss recent results from CLAS and Hall A at Jefferson Lab on the measurement of inclusive spin structure functions in the nucleon resonance region using polarized electron beams and polarized targets. Results on the first moment of the spin structure function for protons and neutrons will be discussed, as well as the Bjorken integral. I will argue that the helicity structure of individual resonances plays a vital role in understanding the nucleon's spin response in the domain of strong interaction QCD, and must be considered in any analysis of the nucleon spin structure at low and intermediate photon virtuality.
Date: August 1, 2002
Creator: Burkert, Volker D.
Object Type: Article
System: The UNT Digital Library