States

Molecular mapping of chromosomes 17 and X (open access)

Molecular mapping of chromosomes 17 and X

Progress toward the construction of high density genetic maps of chromosomes 17 and X has been made by isolating and characterizing a relatively large set of polymorphic probes for each chromosome and using these probes to construct genetic maps. We have mapped the same polymorphic probes against a series of chromosome breakpoints on X and 17. The probes could be assigned to over 30 physical intervals on the X chromosome and 7 intervals on 17. In many cases, this process resulted in improved characterization of the relative locations of the breakpoints with respect to each other and the definition of new physical intervals. The strategy for isolation of the polymorphic clones utilized chromosome specific libraries of 1--15 kb segments from each of the two chromosomes. From these libraries, clones were screened for those detecting restriction fragment length polymorphisms. The markers were further characterized, the chromosomal assignments confirmed and in most cases segments of the original probes were subcloned into plasmids to produce probes with improved signal to noise ratios for use in the genetic marker studies. The linkage studies utilize the CEPH reference families and other well-characterized families in our collection which have been used for genetic disease linkage work. …
Date: January 15, 1991
Creator: Barker, D. F.
Object Type: Report
System: The UNT Digital Library
Molecular mapping of chromosomes 17 and X. Progress report (open access)

Molecular mapping of chromosomes 17 and X. Progress report

Progress toward the construction of high density genetic maps of chromosomes 17 and X has been made by isolating and characterizing a relatively large set of polymorphic probes for each chromosome and using these probes to construct genetic maps. We have mapped the same polymorphic probes against a series of chromosome breakpoints on X and 17. The probes could be assigned to over 30 physical intervals on the X chromosome and 7 intervals on 17. In many cases, this process resulted in improved characterization of the relative locations of the breakpoints with respect to each other and the definition of new physical intervals. The strategy for isolation of the polymorphic clones utilized chromosome specific libraries of 1--15 kb segments from each of the two chromosomes. From these libraries, clones were screened for those detecting restriction fragment length polymorphisms. The markers were further characterized, the chromosomal assignments confirmed and in most cases segments of the original probes were subcloned into plasmids to produce probes with improved signal to noise ratios for use in the genetic marker studies. The linkage studies utilize the CEPH reference families and other well-characterized families in our collection which have been used for genetic disease linkage work. …
Date: January 15, 1991
Creator: Barker, D. F.
Object Type: Report
System: The UNT Digital Library
Physics issues in the design of a recirculating induction accelerator for heavy ion fusion (open access)

Physics issues in the design of a recirculating induction accelerator for heavy ion fusion

A substantial savings in size and cost over a linear machine may be achieved in an induction accelerator in which a heavy ion beam makes many (< {approximately} 50) passes through one or more circular induction accelerators. We examine how the requirement of high beam quality and the requirement of pulse simultaneity at the target constrain the design of such an accelerator. Some of the issues that we have considered include beam interactions with residual gas, beam-beam charge exchange, emittance growth around bends, and beam instabilities. We show some of the interplay between maximization of beam quality and recirculator efficiency, and the minimization of recirculator cost, in arriving at a recirculator design. 9 refs., 1 fig.
Date: April 15, 1991
Creator: Barnard, J. J.; Newton, M. A.; Reginato, L. L.; Sharp, W. M. & Yu, S. S.
Object Type: Article
System: The UNT Digital Library
Cavity design and beam simulations for the APS rf gun (open access)

Cavity design and beam simulations for the APS rf gun

An earlier note discussed the preliminary design of the 1-1/2 cell RF cavity for the APS RF gun. This note describes the final design, including cavity properties and simulation results from the program rf gun. The basic idea for the new design was that the successful SSRL design could be improved upon by reducing fields that had nonlinear dependence on radius. As discussed previously, this would reduce the emittance and produce tighter momentum and time distributions. In addition, it was desirable to increase the fields in the first half-cell relative to the fields in the second half-cell, in order to allow more rapid initial acceleration, which would reduce the effects of space charge. Both of these goals were accomplished in the new design.
Date: November 15, 1991
Creator: Borland, M.
Object Type: Report
System: The UNT Digital Library
The limnology of L Lake: Results of the L-Lake monitoring program, 1986--1989 (open access)

The limnology of L Lake: Results of the L-Lake monitoring program, 1986--1989

L Lake was constructed in 1985 on the upper regions of Steel Creek, SRS to mitigate the heated effluents from L Reactor. In addition to the NPDES permit specifications (Outfall L-007) for the L-Reactor outfall, DOE-SR executed an agreement with the South Carolina Department of Health and Environmental Control (SCDHEC), that thermal effluents from L-Reactor will not substantially alter ecosystem components in the approximate lower half of L Lake. This region should be inhabited by Balanced (Indigenous) Biological Communities (BBCs) in accordance with Section 316(a) of the Pollution Control (Clean Water) Act (Public Law 92-500). In response to this requirement the Environmental Sciences Section/Ecology Group initiated a comprehensive biomonitoring program which documented the development of BBCs in L Lake from January 1986 through December 1989. This report summarizes the principal results of the program with regards to BBC compliance issues and community succession in L Lake. The results are divided into six sections: water quality, macronutrients, and phytoplankton, aquatic macrophytes, zooplankton, benthic macroinvertebrates, fish, and community succession. One of the prime goals of the program was to detect potential reactor impacts on L Lake.
Date: December 15, 1991
Creator: Bowers, J. A.
Object Type: Report
System: The UNT Digital Library
The limnology of L Lake: Results of the L-Lake monitoring program, 1986--1989 (open access)

The limnology of L Lake: Results of the L-Lake monitoring program, 1986--1989

L Lake was constructed in 1985 on the upper regions of Steel Creek, SRS to mitigate the heated effluents from L Reactor. In addition to the NPDES permit specifications (Outfall L-007) for the L-Reactor outfall, DOE-SR executed an agreement with the South Carolina Department of Health and Environmental Control (SCDHEC), that thermal effluents from L-Reactor will not substantially alter ecosystem components in the approximate lower half of L Lake. This region should be inhabited by Balanced (Indigenous) Biological Communities (BBCs) in accordance with Section 316(a) of the Pollution Control (Clean Water) Act (Public Law 92-500). In response to this requirement the Environmental Sciences Section/Ecology Group initiated a comprehensive biomonitoring program which documented the development of BBCs in L Lake from January 1986 through December 1989. This report summarizes the principal results of the program with regards to BBC compliance issues and community succession in L Lake. The results are divided into six sections: water quality, macronutrients, and phytoplankton, aquatic macrophytes, zooplankton, benthic macroinvertebrates, fish, and community succession. One of the prime goals of the program was to detect potential reactor impacts on L Lake.
Date: December 15, 1991
Creator: Bowers, J.A.
Object Type: Report
System: The UNT Digital Library
Emittance measurement in a magnetic field (open access)

Emittance measurement in a magnetic field

Emittance can be measured by intercepting an electron beam on a range thick plate and then observing the expansion of beamlets transmitted through small holes. The hole size is selected to minimize space charge effects. In the presence of a magnetic field the beamlets have a spiral trajectory and the usual field free formulation must be modified. To interpret emittance in the presence of a magnetic field an envelope equation is derived in the appropriate rotating frame. 1 ref.
Date: April 15, 1991
Creator: Boyd, J.K.
Object Type: Article
System: The UNT Digital Library
Photoexcited charge pair escape and recombination. Progress report, November 15, 1990--November 14, 1991 (open access)

Photoexcited charge pair escape and recombination. Progress report, November 15, 1990--November 14, 1991

We report photocurrent transients arising from the pulsed laser excitation of the dipolar first excited singlet sate S{sub 1} of trans 4-dimethyl-amino-4{prime}-nitrostilbene (DMANS) in toluene solution. The currents arise from rotational reorientation of DMANS dipoles with respect to the axis of an applied electric field. The method appears to offer a simple and general approach to the measurement of the change in dipole moment upon electronic excitation of a molecule. In another experiment, durene (1,2,4,5-tetramethylbenzene) dissolved in n-hexane was photoionized by 35 psec pulses at 266 nm. Transient absorption at 1064 nm arising chiefly from geminate electrons was detected and used to monitor the recombination of the electron-cation pairs produced by two-photon ionization. An excellent fit to the recombination kinetics was obtained by assuming that the distribution of initial electron-cation separations was of the form r{sup 2}EXP = r{sup 2}/(2L{sup 3})exp({minus}r/L) with a mean radius 3L = 5.7 nm.
Date: November 15, 1991
Creator: Braun, C. L.
Object Type: Report
System: The UNT Digital Library
Photoexcited Charge Pair Escape and Recombination (open access)

Photoexcited Charge Pair Escape and Recombination

We report photocurrent transients arising from the pulsed laser excitation of the dipolar first excited singlet sate S{sub 1} of trans 4-dimethyl-amino-4{prime}-nitrostilbene (DMANS) in toluene solution. The currents arise from rotational reorientation of DMANS dipoles with respect to the axis of an applied electric field. The method appears to offer a simple and general approach to the measurement of the change in dipole moment upon electronic excitation of a molecule. In another experiment, durene (1,2,4,5-tetramethylbenzene) dissolved in n-hexane was photoionized by 35 psec pulses at 266 nm. Transient absorption at 1064 nm arising chiefly from geminate electrons was detected and used to monitor the recombination of the electron-cation pairs produced by two-photon ionization. An excellent fit to the recombination kinetics was obtained by assuming that the distribution of initial electron-cation separations was of the form r{sup 2}EXP = r{sup 2}/(2L{sup 3})exp({minus}r/L) with a mean radius 3L = 5.7 nm.
Date: November 15, 1991
Creator: Braun, Charles L.
Object Type: Report
System: The UNT Digital Library
Determining desorption pre-exponential factors from temperature-programmed desorption spectra when the surface is nonuniform (open access)

Determining desorption pre-exponential factors from temperature-programmed desorption spectra when the surface is nonuniform

To find desorption pre-exponential factors from temperature-programmed desorption (TPD) spectra, we develop procedures using both the TPD spectra and their derivatives. First, an approximate method is derived using peak temperatures. This method is formally identical with one used for determining pre-exponential factors and desorption activation energies when desorptions are energetically uniform. The method can be used when the pre-exponential factor is constant. We next develop an iterative process that also uses peak temperatures, and again is usable when the pre-exponential factor is constant. This iterative approach should give more exact values of pre-exponential factors than the approximate approach. Using the first derivatives of TPD spectra over the entire range of temperatures leads to a second iterative process. This last procedure allows determination of energy-dependent pre-exponential factors. 8 refs., 13 figs.
Date: March 15, 1991
Creator: Brown, Lee F. & Chemburkar, Rajeey M.
Object Type: Article
System: The UNT Digital Library
Safety questions relevant to nuclear thermal propulsion (open access)

Safety questions relevant to nuclear thermal propulsion

Nuclear propulsion is necessary for successful Mars exploration to enhance crew safety and reduce mission costs. Safety concerns are considered by some to be an implements to the use of nuclear thermal rockets for these missions. Therefore, an assessment was made of the various types of possible accident conditions that might occur and whether design or operational solutions exist. With the previous work on the NERVA nuclear rocket, most of the issues have been addressed in some detail. Thus, a large data base exist to use in an agreement. The assessment includes evaluating both ground, launch, space operations and disposal conditions. The conclusion is that design and operational solutions do exist for the safe use of nuclear thermal rockets and that both the environment and crews be protected against harmful radiation. Further, it is concluded that the use of nuclear thermal propulsion will reduce the radiation and mission risks to the Mars crews.
Date: October 15, 1991
Creator: Buden, D.
Object Type: Article
System: The UNT Digital Library
Safety questions relevant to nuclear thermal propulsion (open access)

Safety questions relevant to nuclear thermal propulsion

Nuclear propulsion is necessary for successful Mars exploration to enhance crew safety and reduce mission costs. Safety concerns are considered by some to be an implements to the use of nuclear thermal rockets for these missions. Therefore, an assessment was made of the various types of possible accident conditions that might occur and whether design or operational solutions exist. With the previous work on the NERVA nuclear rocket, most of the issues have been addressed in some detail. Thus, a large data base exist to use in an agreement. The assessment includes evaluating both ground, launch, space operations and disposal conditions. The conclusion is that design and operational solutions do exist for the safe use of nuclear thermal rockets and that both the environment and crews be protected against harmful radiation. Further, it is concluded that the use of nuclear thermal propulsion will reduce the radiation and mission risks to the Mars crews.
Date: October 15, 1991
Creator: Buden, D.
Object Type: Article
System: The UNT Digital Library
Fuel savings in the heavy trucking industry through cool storage (open access)

Fuel savings in the heavy trucking industry through cool storage

Overnight idling wastes considerable amounts of fuel, contributes to noise and air pollution and adds significantly to trucker's operating costs. Costs are increased because of both the fuel wasted and the additional maintenance required on the engine as a result of extended idling. In winter, idling not only allows a resting driver to keep warm but prevents cold weather battery, fuel gelling and engine starting problems. In the summer, however, the only reason for overnight idling is to keep the sleeper compartment habitable for the resting driver and diesel engine idling to accomplish this is a massive overkill. A novel, patented, cool storage system has been developed by the Instatherm Company. This system allows comfortable summer resting conditions for the driver without having to idle the engine or having to start or run any other auxiliary engine. The operating principle is very straightforward -- store cool'' from the truck air conditioning system, while the vehicle is driven on the highway and to use this stored cool'' to air condition the sleeper compartment while the driver rests. 17 figs.
Date: September 15, 1991
Creator: Carr, P.
Object Type: Report
System: The UNT Digital Library
The Properties and Weldability of Materials for Fusion Reactor Applications (open access)

The Properties and Weldability of Materials for Fusion Reactor Applications

Low-activation austenitic stainless steels have been suggested for applications within fusion reactors. The use of these nickel-free steels will help to reduce the radioactive waste management problem after service. one requirement for such steels is the ability to obtain sound welds for fabrication purposes. Thus, two austenitic Fe-Cr-Mn alloys were studied to characterize the welded microstructure and mechanical properties. The two steels investigated were a Russian steel (Fe-11.6Cr19.3Mn-0.181C) and an US steel (Fe-12.lCr-19.4Mn-0.24C). Welding was performed using a gas tungsten arc welding (GTAW) process. Microscopic examinations of the structure of both steels were conducted. The as-received Russian steel was found to be in the annealed state. Only the fusion zone and the base metal were observed in the welded Russian steel. No visible heat affected zone was observed. Examination revealed that the as-received US steel was in the cold rolled condition. After welding, a fusion zone and a heat affected zone along with the base metal region were found.
Date: November 15, 1991
Creator: Chin, B. A.; Kee, C. K.; Wilcox, R. C. & Zinkle, S. J.
Object Type: Report
System: The UNT Digital Library
The Properties and Weldability of Materials for Fusion Reactor Applications (open access)

The Properties and Weldability of Materials for Fusion Reactor Applications

Low-activation austenitic stainless steels have been suggested for applications within fusion reactors. The use of these nickel-free steels will help to reduce the radioactive waste management problem after service. one requirement for such steels is the ability to obtain sound welds for fabrication purposes. Thus, two austenitic Fe-Cr-Mn alloys were studied to characterize the welded microstructure and mechanical properties. The two steels investigated were a Russian steel (Fe-11.6Cr19.3Mn-0.181C) and an US steel (Fe-12.lCr-19.4Mn-0.24C). Welding was performed using a gas tungsten arc welding (GTAW) process. Microscopic examinations of the structure of both steels were conducted. The as-received Russian steel was found to be in the annealed state. Only the fusion zone and the base metal were observed in the welded Russian steel. No visible heat affected zone was observed. Examination revealed that the as-received US steel was in the cold rolled condition. After welding, a fusion zone and a heat affected zone along with the base metal region were found.
Date: November 15, 1991
Creator: Chin, B. A.; Kee, C. K.; Wilcox, R. C. & Zinkle, S. J.
Object Type: Report
System: The UNT Digital Library
First-principles Studies of Phase Stability and the Structural and Dynamical Properties of Metal Hydrides. Annual Technical Progress Report, September 15, 1990--May 15, 1991 (open access)

First-principles Studies of Phase Stability and the Structural and Dynamical Properties of Metal Hydrides. Annual Technical Progress Report, September 15, 1990--May 15, 1991

We decided to investigate first the interaction of hydrogen with the 4d transition-metal series, with the first element being hcp Y. Because of the recent development of soft pseudopotentials, we chose to use the plane wave basis set to carry out the calculation. Since problems had been associated with the slow convergence in transition metals, we first tested the computational methods by studying the structural properties of Y; results were encouraging. We started the calculation of YH{sub x} with hydrogen occupying different interstitial sites.
Date: May 15, 1991
Creator: Chou, M. Y.
Object Type: Report
System: The UNT Digital Library
First-principles Studies of Phase Stability and the Structural and Dynamical Properties of Metal Hydrides (open access)

First-principles Studies of Phase Stability and the Structural and Dynamical Properties of Metal Hydrides

We decided to investigate first the interaction of hydrogen with the 4d transition-metal series, with the first element being hcp Y. Because of the recent development of soft pseudopotentials, we chose to use the plane wave basis set to carry out the calculation. Since problems had been associated with the slow convergence in transition metals, we first tested the computational methods by studying the structural properties of Y; results were encouraging. We started the calculation of YH[sub x] with hydrogen occupying different interstitial sites.
Date: May 15, 1991
Creator: Chou, M.Y.
Object Type: Report
System: The UNT Digital Library
Particle deposition in human and canine tracheobronchial casts. Annual progress report (open access)

Particle deposition in human and canine tracheobronchial casts. Annual progress report

The aim of this work is to measure deposition patterns and efficiencies of aerosol particles within realistic, single-pathway physical models of the tracheobronchial airways of humans and experimental animals over a range of particle sizes for a variety of respiratory modes and rates. This will provide data needed to assess the dose to the bronchial epithelium from inhaled radon progeny. In prior grant years an empirical expression for diffusional deposition efficiency of particles in the upper airways was obtained based on experimental data collected in central airway casts. The work also provided new quantitative data of airflow distribution in a realistic central airway cast for two species for both steady and pulsatile inspiratory flow and for expiratory flow. Theoretical studies were then extended based on a developing flow model. We concluded that although the developing flow model is a better predictor of the data than assumption of parabolic flow, the predicted deposition is significantly lower than that predicted by our best fit equation. In the current year the experimental results were evaluated in terms of the parametric solution of the convective diffusion equation.
Date: November 15, 1991
Creator: Cohen, B. S.
Object Type: Report
System: The UNT Digital Library
Particle deposition in human and canine tracheobronchial casts (open access)

Particle deposition in human and canine tracheobronchial casts

The aim of this work is to measure deposition patterns and efficiencies of aerosol particles within realistic, single-pathway physical models of the tracheobronchial airways of humans and experimental animals over a range of particle sizes for a variety of respiratory modes and rates. This will provide data needed to assess the dose to the bronchial epithelium from inhaled radon progeny. In the current year theoretical studies based on a developing flow model were extended. We concluded that although the developing flow model is better predictor of the data than assumption of parabolic flow, the predicated deposition is significantly lower than that predicted by our best fit equation. The mass size dispersion of particles classified according to their electrical mobilities was also studies. For the conditions tested, doubly charged particles constituted 9--13% of the total particle number concentration and 24--48% of the total mass concentration. We demonstrated that the multiply charged particles are effectively removed, and nearly monodisperse particles produced, if an impactor is placed in the aerosol generation system. A condensation aerosol generator was constructed and tested for the production of high concentrations of radioactively tagged aerosol particles with diameters from 0.2 to 10{mu}m. 9 refs.
Date: January 15, 1991
Creator: Cohen, B.S.
Object Type: Report
System: The UNT Digital Library
Particle deposition in human and canine tracheobronchial casts (open access)

Particle deposition in human and canine tracheobronchial casts

The aim of this work is to measure deposition patterns and efficiencies of aerosol particles within realistic, single-pathway physical models of the tracheobronchial airways of humans and experimental animals over a range of particle sizes for a variety of respiratory modes and rates. This will provide data needed to assess the dose to the bronchial epithelium from inhaled radon progeny. In prior grant years an empirical expression for diffusional deposition efficiency of particles in the upper airways was obtained based on experimental data collected in central airway casts. The work also provided new quantitative data of airflow distribution in a realistic central airway cast for two species for both steady and pulsatile inspiratory flow and for expiratory flow. Theoretical studies were then extended based on a developing flow model. We concluded that although the developing flow model is a better predictor of the data than assumption of parabolic flow, the predicted deposition is significantly lower than that predicted by our best fit equation. In the current year the experimental results were evaluated in terms of the parametric solution of the convective diffusion equation.
Date: November 15, 1991
Creator: Cohen, B.S.
Object Type: Report
System: The UNT Digital Library
War Powers Resolution : Presidential Compliance (open access)

War Powers Resolution : Presidential Compliance

This report is about War Power Resolution
Date: January 15, 1991
Creator: Collier, Ellen C.
Object Type: Report
System: The UNT Digital Library
A remote telepresence robotic system for inspection and maintenance of a nuclear power plant (open access)

A remote telepresence robotic system for inspection and maintenance of a nuclear power plant

This annual report details the activities of the University of Florida research on the robotic system for inspection and maintenance of nuclear power plants. (FI)
Date: December 15, 1991
Creator: Crane, C. D., III & Tulenko, J. S.
Object Type: Report
System: The UNT Digital Library
A remote telepresence robotic system for inspection and maintenance of a nuclear power plant. DOE/NE program in robotics for advanced reactors: Annual research status report, 1991 (open access)

A remote telepresence robotic system for inspection and maintenance of a nuclear power plant. DOE/NE program in robotics for advanced reactors: Annual research status report, 1991

This annual report details the activities of the University of Florida research on the robotic system for inspection and maintenance of nuclear power plants. (FI)
Date: December 15, 1991
Creator: Crane, C. D., III & Tulenko, J. S.
Object Type: Report
System: The UNT Digital Library
Simulation studies to evaluate the effect of fracture closure on the performance of naturally fractured reservoirs (open access)

Simulation studies to evaluate the effect of fracture closure on the performance of naturally fractured reservoirs

The study has two principal objectives: (1) To evaluate the effects of fracture closure on the recovery of oil and gas reserves from naturally fractured petroleum or natural gas reservoirs. (2) To evaluate procedures for improving the recovery of these reserves using innovative fluid injection techniques to maintain reservoir pressure and mitigate the impact of fracture closure. The total scope of the study has been subdivided into three main tasks: (1) Baseline studies (non-pressure sensitive fractures); (2)studies with pressure sensitive fractures; and (3) innovative approaches for improving oil recovery.
Date: July 15, 1991
Creator: Dauben, D.L.
Object Type: Report
System: The UNT Digital Library