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Heat transfer coefficient in serpentine coolant passage for CCDTL

Description: A series of heat transfer experiments were conducted to refine the cooling passage design in the drift tubes of a coupled cavity drift tube linac (CCDTL). The experimental data were then compared to numerical models to derive relationships between heat transfer rates, Reynold`s number, and Prandtl number, over a range of flow rates. Data reduction consisted of axisymmetric finite element modeling where the heat transfer coefficients were modified to match the experimental data. Unfortunately, the derived relationship is valid only for this specific geometry of the test drift tube. Fortunately, the heat transfer rates were much better (approximately 2.5 times) than expected.
Date: December 31, 1998
Creator: Leslie, P.; Wood, R.; Sigler, F.; Shapiro, A. & Rendon, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Trace identification of organic moleculses in ultrapure water using Ion Mobility Spectroscopy

Description: Preliminary laboratory investigations have indicated that Ion Mobility Spectroscopy is capable of detecting many of the contaminants found in UPW systems. The sensitivity and response time meets the requirements for UPW monitoring. Minor hardware and software modifications must be made for on-line use, and the instrument must be tested for robustness, stability, reproducibility, and similar parameters. Resolution issues between the reactant ions and some target species must still be addressed.
Date: February 1, 1996
Creator: Rodacy, P.; Leslie, P.; Klassen, S. & Silva, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department

Destruction of explosives in groundwater and process water using photocatalytic and biological methods

Description: The environmentally safe destruction of pinkwater is a significant problem that requires a multidisciplinary approach to solve. We have investigated the application of advanced oxidation processes, including the use of both UV light source and laser technologies. The reactions were run under both oxidizing and reducing atmospheres. Aerobic and anaerobic biotreatments were examined as both pre- and post-treatments to the oxidation processes. The toxicity of the wastewater at various stages of treatment was determined. Membrane preconcentration schemes were examined to determine their effectiveness as part of the total pinkwater treatment scheme.
Date: April 1, 1996
Creator: Rodacy, P.J.; Leslie, P.K. & Prairie, M.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

The Effects of Video-Computerized Feedback on Competitive State Anxiety, Self-Efficacy, Effort, and Baseball Hitting-Task Performance

Description: This study examined the effects of frame-by-frame video-computerized feedback on competitive state anxiety, self-efficacy, effort, and baseball performance of high school players. Players were randomly assigned to one of three feedback conditions: (a) Hitting score, (b) Hitting score and frame-by-frame analysis of a mechanically correct swing, (c) Hitting score and frame-by-frame analysis of participant's swing and a mechanically correct swing. Once per week for six weeks, the players completed three questionnaires: (a) Hitting Self-Efficacy Scale, (b) Competitive State Anxiety Inventory-2C, and (c) Performance Effort Scale, and performed a hitting task. Results of the 3 (Group) x 6 (Trials) ANOVAs revealed no significant effects. This study does not support previous confidence-baseball hitting research.
Date: December 1998
Creator: Leslie, P. Jason
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Advances in preparing and characterizing low density pan-carbon microcellular foam

Description: This report documents an improved preparation of low density microcellular carbon as well as characterization of spatial homogeneity. The report also documents the process for preparing the nficrocellular carbon from poly(acrylonitrile) raw material. A microcellular polymer precursor (0.025 g/cc) is first prepared via a solution-based process and then pyrolyzed to produce the microcellular carbon in a monolithic form (0.05 g/cc). The process improvement developed in this study permits the pore structure of the n-ficrocellular polymer precursor and the microcellular carbon to be reproduced consistently in different laboratories. Pore structure is affected by the completeness of dissolution of the polymer raw material, which variable can be adjusted via dissolution temperature or particle size of the raw material. The second topic in this report involves determining the spatial fluctuation in mass density caused by periodic, millimeter-scale bands, known as `tree rings` visible on machined surfaces of the carbon monoliths. To measure the fluctuations, we developed a high precision, spatially resolved X-ray transmission technique. The periodic bands caused less than {plus_minus}2% variation of mass density in a microcellular carbon having average density 0.041 g/cc.
Date: September 1, 1993
Creator: Lagasse, R. R.; Leslie, P. K.; Thompson, K. R. & Weagley, R. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Principals' Perceptions of Organizational Practices and Decision Making Roles in Middle Level Schools

Description: The problem addressed in this study was whether middle level schools have adopted currently held research findings with respect to organizational structure and decision making processes promoted by the work of the Carnegie Foundation and various state agencies. Purposes included determining the perceptions of principals in schools utilizing interdisciplinary teams of teachers regarding the roles of principals and teachers in decision making processes, differences in campus performance on the Texas Assessment of Academic Skills and specific demographic variables in comparison to perceptions of principals in schools not utilizing interdisciplinary teams on these same questions.
Date: August 1994
Creator: Evans, Leslie P. (Leslie Paul), 1954-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Photocatalysis for the destruction of aqueous TNT, RDX, and HMX

Description: The photo-destruction of the high explosives HMX, RDX and TNT was investigated using two systems (ozone versus titanium dioxide), two reactors (pot vs annular reactor), and two types of lamps (1000 Watt Hg-Xe vs 25 Watt LP Hg). A mass balance was performed on reactions executed under pseudo-solar conditions, and relative reaction rates and products were compared for ozone and titanium dioxide based processes. The ratios of relative product formation is also discussed. Results show that there was little difference in the reactions performed in the annular reactor when either ozone or titanium oxide were used. The chemistry of RDX and HMX are very similar, as expected. Future work involving the mechanism is also discussed.
Date: December 31, 1994
Creator: Showalter, S. K.; Prairie, M. R.; Stange, B. M.; Rodacy, P. J. & Leslie, P. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department

Status of engineering development of CCDTL for accelerator production of tritium

Description: The Coupled-Cavity Drift Tube Linac (CCDTL) is a relatively new RF accelerator structure which plays a major role in the APT Low-Energy Linac (LEL) design. Engineering development is pushing ahead on several fronts, including thermal management, fabrication procedures, cavity and coupling slot tuning, high-power prototype fabrication and testing, supports and alignment, vacuum, and provisions for beam diagnostics. Fabrication of the CCDTL Low-Beta Hot Model is nearly complete, and high-power RF tests will commence soon. In 1999, the authors will begin the fabrication of 11 meters of CCDTL to be added to the Low-Energy Demonstration Accelerator. In 2001, it will take the 100 mA beam from 6.7 MeV to 10.05 MeV, producing the world`s most powerful proton beam. The authors are also starting the design of a CCDTL 96 MeV Hot Model to demonstrate cooling of an intermediate-Beta version of the structure. The 14cm-long, 9cm diameter drift tube has roughly 5kW dissipated on it. This all leads to the final mechanical design of the 113m long CCDTL for the APT plant linac.
Date: December 31, 1998
Creator: Wood, R.L.; Billen, J.H.; Hunter, W.T.; Leslie, P.O.; Roybal, R.J. & Sigler, F.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department

Phenomena affecting morphology of microporous poly(acrylonitrile) prepared via phase separation from solution

Description: This paper is concerned with controlling the morphology of microporous polymers prepared via thermal demixing of solutions. 2 wt % solutions of poly(acrylonitrile) in maleic anhydride, a poor solvent, are first cooled to produce separated polymer-rich and solvent-rich phases. Removing the solvent by freeze drying then produces a microporous material having a density of 33 mg/cm{sup 3}, a void fraction of 97%, and a pore size of about 10 {mu}m. We find that the morphology cannot be explained by existing models, which focus on phase diagrams and kinetics of phase transformations during cooling of the solution. In conflict with those models, we find that two radically different morphologies can be produced even when the polymer concentration and cooling path are held strictly constant. A hypothesis that polymer degradation causes the different morphologies is not supported by GPC, {sup 13}C NMR, and FTIR experiments. Instead, we offer evidence that the different microporous morphologies are caused by different polymer conformations in solutions having the same concentration and temperature. 11 refs., 3 figs.
Date: January 1, 1990
Creator: Legasse, R.R.; Weagley, R.J.; Leslie, P.K. & Schneider, D.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department

TUNING SECTION 2 OF THE LEDA CCDTL

Description: As part of the Low-Energy Demonstration Accelerator (LEDA) portion of the Advanced Accelerator Applications (AAA) project we have fabricated and will perform high-power RF tests on Section 2 of the 700-MHz Coupled-Cavity Drift-Tube Linac (CCDTL). This CCDTL section contains six, two-gap accelerating cells. This portion of the CCDTL was designed to accelerate the 100-mA, LEDA RFQ proton beam to 7.3 MeV. This paper reports on the process and results of tuning Section 2 leading up to high-power RF testing.
Date: January 1, 2001
Creator: Rybarcyk, L. J. (Lawrence J.); L.), Wood R. L. (Richard; Leslie, P. O. (Paul O.); Valdiviez, R. (Robert); Cole, M. D. (Michael D.) & Potter, J. M. (James M.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department