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Elimination reaction of 2-hydroxyalkyloobaloximes in acidic solution

Description: Research is reported on the establishment of a rate law and mechanism for the ..beta..-OH-alkylcobaloxime decomposition reaction in acid media. The compounds used in the study are ..beta..-OH-Et(Co)py (or H/sub 2/O), ..beta..-OH-i-Pr(Co)py (or H/sub 2/O), ..beta..-OH-n-Pr(Co)py (or H/sub 2/O), and ..beta..-OH-n-PrCo(DBF/sub 2/)/sub 2/py. These cobaloximes were used as model compounds for the cobalamins, the vitamin B group.
Date: January 1, 1979
Creator: Wang, D.M.L.
Partner: UNT Libraries Government Documents Department

Decontamination and decommissioning of the EBR-I Complex. Final report

Description: This final report covers the Decontamination and Decommissioning (D and D) of the Experimental Breeder Reactor No. 1 (EBR-I) Complex funded under Contract No. AT(10-1)-1375. The major effort consisted of removal and processing of 5500 gallons of sodium/potassium (NaK) coolant from the EBR-I reactor system. Tests were performed to assess the explosive hazards of NaK and KO$sub 2$ in various environments and in contact with various contaminants likely to be encountered in the removal and processing operations. A NaK process plant was designed and constructed and the operation was successfully completed. Lesser effort was required for D and D of the Zero Power Reactor (ZPR-III) Facility, the Argonne Fast Source Reactor (AFSR) Shielding, and removal of contaminated NaK from the storage pit. The D and D effort was completed by 13 June 1975, ahead of schedule. (auth)
Date: July 1, 1975
Creator: Kendall, E.W. & Wang, D.K.
Partner: UNT Libraries Government Documents Department

SURFING: A Program for Precise Determination of Sample Position in Stress Measurements Via Neutron Diffraction

Description: Precise determination of the specimen position relative to the sampling volume for texture and stress measurements by neutron diffraction is difficult or sometimes impossible using only optical devices due to large or irregular sample dimensions and/or complicated shape of the sampling volume. The knowledge of the shape and size of the sampling volume allows development of a general mathematical model for the intensity variation with a parallelogram-shape sampling volume moving from outside to inside the specimen for both transmission and reflection geometric set-ups. Both fixed slits and radial collimators are options in defining the geometrical setup. The attenuation by the sample also has been taken into account in this model. Experimental results agree well with the model calculations. The program SURFING is based on the model calculation and was written in Labwindows/CVI{copyright}.
Date: August 8, 2000
Creator: Wang, D.-Q.
Partner: UNT Libraries Government Documents Department

Dielectric relaxation from a network of charged defects in dilute CeO/sub 2/:Y/sub 2/O/sub 3/ solid solutions

Description: Solid solutions of Y/sub 2/O/sub 3/ in CeO/sub 2/ are examined by the thermal depolarization (or ITC) method of dielectric relaxation. For concentrations less than or equal to 1 m/o Y/sub 2/O/sub 3/, two peaks are observed. The lower temperature peak, Peak 1, is interpreted as due to the relaxation of nn YV/sub 0/ pairs (where V/sub 0/ = oxygen vacancy, and is analogous to the well-known CaV/sub 0/ pair obtained with Ca/sup 2 +/ doping. The upper peak, Peak 2, on the other hand, is a broad peak whose position is a function of concentration. It is not due to simple dipoles, but originates in the network of alternately charged (YV/sub 0/)/sup ./ pairs and isolated Y' defects by redistribution of vacancies.
Date: January 1, 1981
Creator: Wang, D.Y. & Nowick, A.S.
Partner: UNT Libraries Government Documents Department

Measurement of short bunches

Description: In recent years, there has been increasing interest in short electron bunches for different applications such as short wavelength FELs, linear colliders, and advanced accelerators such as laser or plasma wakefield accelerators. One would like to meet various requirements such as high peak current, low momentum spread, high luminosity, small ratio of bunch length to plasma wavelength, and accurate timing. Meanwhile, recent development and advances in RF photoinjectors and various bunching schemes make it possible to generate very short electron bunches. Measuring the longitudinal profile and monitoring bunch length are critical to understand the bunching process and longitudinal beam dynamics, and to commission and operate such short bunch machines. In this paper, several commonly used measurement techniques for subpicosecond bunches and their relative advantages and disadvantages are discussed. As examples, bunch length related measurements at Jefferson lab are presented. At Jefferson Lab, bunch lengths s short as 84 fs have been systematically measured using a zero-phasing technique. A highly sensitive Coherent Synchrotron Radiation (CSR) detector has been developed to noninvasively monitor bunch length for low charge bunches. Phase transfer function measurements provide a means of correcting RF phase drifts and reproducing RF phases to within a couple of tenths of a degree. The measurement results are in excellent agreement with simulations. A comprehensive bunch length control scheme is presented.
Date: October 1, 1996
Creator: Wang, D.X.
Partner: UNT Libraries Government Documents Department

Experimental studies of longitudinal dynamics of space-charge dominated electron beams

Description: A comprehensive experimental program was carried out at Univ. of Maryland Beam Transport facility to study the longitudinal beam physics of space-charge dominated bunches. This investigation included the behavior of (a) bunches with parabolic line charge profile, (b) bunches with rectangular line charge profile, and (c) local perturbations (slow and fast waves) in rectangular bunches. The major experimental results are presented in this paper.
Date: December 31, 1995
Creator: Wang, D. X.
Partner: UNT Libraries Government Documents Department

Electron beam instrumentation techniques using coherent radiation

Description: Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed.
Date: June 1, 1997
Creator: Wang, D.X.
Partner: UNT Libraries Government Documents Department


Description: The H permeation of internally oxidized Pd alloy membranes such as Pd-Al and Pd-Fe, but not Pd-Y alloys, is shown to be more resistant to inhibition by CO(g) as compared to Pd or un-oxidized Pd alloy membranes. The increased resistance to CO is found to be greater at 423 K than at 473 K or 523 K. In these experiments CO was pre-adsorbed onto the membranes and then CO-free H{sub 2} was introduced to initiate the H permeation.
Date: October 20, 2010
Creator: Shanahan, K.; Flanagan, T. & Wang, D.
Partner: UNT Libraries Government Documents Department

Current meter data report, September 1980 - December 1980: mooring OTEC-HB

Description: Data tapes contained current meter records from instrumented mooring OTEC-HB near the OTEC-1 site approximately 14 nautical miles northwest of Keahole Point, Island of Hawaii. Deployed in 1345 m of water, the mooring had five Aanderaa RCM-5 current meters, one at each of the following depths: 47 m, 70m, 99m, 154m, and 829 m. Raw data consisted of east-west (U) velocity, north-south (V) velocity, temperature (T), and pressure (P) time series from September 23, 1980, through December 20, 1980, with a recording interval of 15 min. The series (U, V, T) were filtered into various frequency domains, thereby removing very high frequencies and separating tidal oscillations from very low frequencies. Spectral analyses were performed on the nontidal U and V time series.
Date: March 1, 1981
Creator: Roman, T M & Wang, D P
Partner: UNT Libraries Government Documents Department

Development of high temperature scanning electron microscopy and applications to sintering studies

Description: The densification and microstructural changes of a metallic and/or ceramic powder compact during sintering is a critically important but incompletely understood process. Whether solely in the solid state or in the presence of a liquid phase, mass transport occurs at elevated temperatures to eliminate porosity and reduce the surface energy of the system. Changes in specimen dimensions, particle shape and pore morphology, formation of liquid phases and other direct evidence of the sintering process have been observed and recorded at temperature using video tape and 16mm time lapse movies of the TV scanning image. Materials that have been examined at elevated temperature are Ni, glass, Al/sub 2/O/sub 3/, UO/sub 2/, W, Cu, WC-Co, and CaF/sub 2/.
Date: January 1, 1978
Creator: Wang, D.N.K.; Miller, D.J. & Fulrath, R.M.
Partner: UNT Libraries Government Documents Department

Considerations on Beam Quality Control in MIT X-Ray FEL

Description: The x-ray FEL at MIT is one example of a design for a new generation linac-based light source. Such a new machine requires very high quality electron beams. Besides the usual requirements on beam parameters such as emittance, energy spread, peak current, there are new challenges emerging in the design studies, e.g., the arrival timing of electron beam must reach precision below tens of femtoseconds level to ensure the laser seed overlaps the desired sections of electron bunch in the multiple-stage HGHG process. In this paper we report the progress on design optimization towards high quality and low sensitivity beams.
Date: March 15, 2006
Creator: Wang, D.; Graves, W.; Wang, D.; Zwart, T.; /MIT, Bates Linear Accelerator; Emma, P. et al.
Partner: UNT Libraries Government Documents Department


Description: Under the commonly employed experimental conditions of a significant upstream concentration of H and c{sub H} {approx} 0 downstream, expressions are given for obtaining the concentration-independent D*{sub H} from the concentration dependent D{sub H} employing the known non-ideality. A procedure is given for determining the concentration profile for a given upstream concentration for an alloy where the non-ideality is known as a function of H concentration. For the Pd{sub 0.81}Ag{sub 0.19} alloy (423 K) the nonideality, f(r)<1 decreases the flux but for alloys where the non-ideality is in the opposite direction, f(r)>1, the flux will be greater which would be an advantage for the experimental purification of H{sub 2}.
Date: July 13, 2006
Creator: Shanahan, K; Ted B. Flanagan, T & D. Wang, D
Partner: UNT Libraries Government Documents Department

Community Gardening: a Novel Intervention for Bhutanese Refugees Living in the USA

Description: Since 2008, the United States (USA) has resettled thousands of Bhutanese refugees, providing brief financial support and pathways to citizenship. Despite the efforts of governing bodies and voluntary agencies which facilitate resettlement, many refugees struggle with adapting to the vastly different lifestyle, economy, language and social structures. In particular, effectively addressing psychological needs of this population is a challenge for service providers operating within an expensive health care system based on Western constructs of mental health. In response to this challenge, refugee resettlement agencies throughout the country use community gardens to promote psychological healing, self-sufficiency, community engagement, and a return of human dignity. Though success of these programs is being shared in the media, there has yet to be empirical data examining their impact. The current study tested whether Bhutanese refugee engagement in a community garden impacts symptoms of depression, anxiety, PTSD and somatic complaints. The study also investigated whether community gardening is associated with perceptions of social support and adjustment to life in the United States. Quantitative and qualitative data was collected from 50 adult Bhutanese refugees in Fort Worth, Texas. Gardening was significantly related to increased social support overall, a key factor in overall functionality within communal cultures; and specifically perceived tangible support was increased. A significant effect of gardening was also found for adjustment. Although a significant effect was not found for psychological and somatic symptoms, there is still evidence of effects on somatic complaints. Varying results from quantitative and qualitative data warrant further investigation into the nuanced work of clinical research and advocacy with refugee populations.
Date: August 2015
Creator: Gerber, Monica M.
Partner: UNT Libraries

Do the Defects Make it Work? Defect Engineering in ..pi.. - Conjugated Polymer Films and Their Solar Cells (Presentation)

Description: The summaries of this report are: (1) charged defects produce 10{sup 15}-10{sup 17} cm{sup -3} free carriers; (2) treatment with nucleophiles decreases p{sub f} and {sigma} while treatment with electrophiles does not change p{sub f} but increases {sigma}; (3) both treatments increase {mu}{sub p}, L{sub ex} and stability against photo-degradation; (4) charged defects can improve OPV by increasing conductivity and creating interfacial electric fields but they hurt {mu}{sub p}, L{sub ex} and chemical stability; and (5) a better way--synthesize materials without covalent defects and dope with purposely added, bound dopants.
Date: May 1, 2008
Creator: Gregg, B. A.; Wang, D.; Reese, M. O. & Kopidakis, N.
Partner: UNT Libraries Government Documents Department

Do the Defects Make It Work? Defect Engineering in Pi-Conjugated Polymers and Their Solar Cells: Preprint

Description: The charged defect density in common pi-conjugated polymers such as poly(3-hexylthiophene), P3HT, is around 1018 cm-3. Despite, or perhaps because of, this huge defect density, bulk heterojunction solar cells made from these polymers and a C60 derivative such as PCBM exhibit some of the highest efficiencies (~5%) yet obtained in solid state organic photovoltaic cells. We discuss defects in molecular organic semiconductors and in pi-conjugated polymers. These defects can be grouped in two categories, covalent and noncovalent. Somewhat analogous to treating amorphous silicon with hydrogen, we introduce chemical methods to modify the density and charge of the covalent defects in P3HT by treating it with electrophiles such as dimethyl sulfate and nucleophiles such as sodium methoxide. The effects of these treatments on the electrical and photovoltaic properties and stability of organic PV cells is discussed in terms of the change in the number and chemical properties of the defects. Finally, we address the question of whether the efficiency of OPV cells requires the presence of these defects which function as adventitious p-type dopants. Their presence relieves the resistance limitations usually encountered in cleaner organic semiconductors and can create built-in electric fields at junctions.
Date: May 1, 2008
Creator: Wang, D.; Reese, M.; N., Kopidakis & Gregg, B. A.
Partner: UNT Libraries Government Documents Department

H Diffusion through Partially Internally Oxidized Pd-alloy Membranes (U)

Description: In 1998 Kirchheim et al remarked that ''to their knowledge, experimental results on the diffusion of hydrogen through multi-layers have not yet been reported'' [1]. Their research dealt with diffusion through ultra-thin multi-layers of Nb/Pd which they followed electrochemically using a time-lag method. Their results were somewhat uncertain in that no final conclusion about any effect of the internal interfaces could be reached. Very recently Yamakawa et al [2] investigated Pd/Fe and Pd/Ni multilayers at 378-625 K and found no strong influence of the interfaces, however, there was grain boundary diffusion for the Pd/Ni layers and retardation, possibly due to dislocation trapping. Takano et al [3] studied H diffusion through thin layers of Pd, Ni, or Cu deposited electrochemically on Fe and concluded that complications are introduced by thin films perhaps H trapping at vacancies as the thickness of the layer decreases to very small values. Holleck [4] measured H diffusion through mm thick Pd{sub 0.75}Ag{sub 0.25}/Ta/Pd{sub 0.75}Ag{sub 0.25} layers in the gas phase from 540-873 K and determined D{sub H,Ta} from the overall diffusion constant and the known D{sub H,alloy}; he concluded that the interface did not play a significant role at these temperatures. As in Holleck's, the present research does not concern very thin multi-layers but macroscopic ones, in this case, prepared by internal oxidation. The measurements will be carried out at a lower temperature than Holleck's and with a variety of layer thicknesses. Most previous investigations have employed electrochemical time-lag methods [1,3,5,6] at ambient temperature and have assumed that the solubilities at the interfaces are in the ideal range. To our knowledge, an investigation of diffusion through layers prepared by internal oxidation has not been carried out. Partial internal oxidation of Pd-M alloys leads to outer layers of Pd containing M oxide precipitates while the inner layer ...
Date: October 1, 2005
Creator: Wang, D.; Flanagan, Ted B. & Shanahan, K. L.
Partner: UNT Libraries Government Documents Department

Mechanics/heat-transfer relation for particulate materials

Description: The original goal of this study was to try and understand the relationship between the thermal and mechanical properties of particulate flows. Two situations were examined. The first is a study of the effects of simple shear flows, as a embryonic flow type on the apparent thermal conductivity and apparent viscosity of a dry granular flow. The second study involved fluidized beds. The original idea was to try and relate the heat transfer behavior of a fluidized bed to the particle pressure,'' the forces by only the particle phase of the two-phase mixture. (VC)
Date: November 1, 1991
Creator: Campbell, C.S.; Wang, D.G. & Rahman, K.
Partner: UNT Libraries Government Documents Department

Advanced physical coal cleaning to comply with potential air toxic regulations. Quarterly report, 1 December 1994--28 February 1995

Description: Studies have indicated that the potentially hazardous trace elements found in coal have a strong affinity for coal pyrite. Thus, by maximizing the rejection of pyrite, one can minimize the trace element content of a given coal while also reducing sulfur emissions. The pyrite in most Illinois Basin coals, however, is finely disseminated within the coal matrix. Therefore, to remove the pyrite using physical coal cleaning techniques, the pyrite must be liberated by grinding the coal to ultrafine particle sizes. Fortunately, the coals being fed to pulverized coal boilers (PCB) are already ground to a very fine size, i.e., 70% passing 200 mesh. Therefore, this research project will investigate the use of advanced fine coal cleaning technologies for cleaning PCB feed as a compliance strategy. Work in this quarter has focused on the processing of a PCB feed sample collected from Central Illinois Power`s Newton Power Station using column flotation and an enhanced gravity separator as separate units and in a circuitry arrangement. The PCB feed sample having a low ash content of about 12% was further cleaned to 6% while achieving a very high energy recovery of about 90% in a single stage column flotation operation. Enhanced gravity treatment is believed to be providing excellent total sulfur rejection values, although with inferior ash rejection for the {minus}400 mesh size fraction. The circuitry arrangement with the Falcon concentrator as the primary cleaner followed by the Microcel column resulted in an excellent ash rejection performance, which out performed the release analysis. Trace element analyses of the samples collected from these tests will be conducted during the next report period.
Date: December 31, 1995
Creator: Honaker, R.Q.; Paul, B.C. & Wang, D.
Partner: UNT Libraries Government Documents Department

Measuring longitudinal distribution and bunch length of femtosecond bunches with RF zero-phasing method

Description: Recently there has been increasing interest in applications of very short electron bunches. Accurately measuring bunch length and profiles becomes essential for characterizing, commissioning, and operating such short bunch machines. The RF zero-phasing method is the only technique that is able to measure bunch length and longitudinal density distribution in the femtosecond regime. In this paper, analytical formulas for calculating longitudinal profile and bunch length are given. using a such technique, bunch lengths as short as 84 fs rms have been measured.
Date: June 1, 1997
Creator: Wang, D.X. & Krafft, G.A.
Partner: UNT Libraries Government Documents Department

Application of 2-dimensional coordinate system conversion in stress measurements with neutron diffraction

Description: This paper will present a method and program to precisely calculate the coordinates in a positioner coordinate system from given sample position coordinates with a minimum number of neutron surface scans for three possible circumstances in stress and texture measurement using neutron diffraction.
Date: July 10, 2000
Creator: Wang, D.-Q.; Hubbard, C.R. & Spooner, S.
Partner: UNT Libraries Government Documents Department

RF control studies for moderate beamtime coupling between SRF cavities

Description: When an SRF accelerator is designed, there is motivation to move the cavities close together on the beamline. Assuming the beamline apertures are not shrunk as well, this compaction (which will increase the overall accelerating gradient and/or lower the dynamic cryogenic heat load) increases the inter-cavity coupling. Within certain limits, the control system can compensate for this coupling by retuning each of the cavities. This paper describes constraints on the RF system, tuners, couplers, and control systems that are required to provide stable operation of cavities in the presence of inter-cavity coupling that exceeds the loaded bandwidth of an individual cavity.
Date: August 1, 1998
Creator: Doolittle, L. R. & Wang, D. X.
Partner: UNT Libraries Government Documents Department