Degree Level

States

Design and performance of liquid hydrogen target systems for the Fermilab Fixed Target Program (open access)

Design and performance of liquid hydrogen target systems for the Fermilab Fixed Target Program

The Fermilab 1990--1991 Fixed Target Program featured six experiments utilizing liquid hydrogen or liquid deuterium targets as part of their apparatus. Each design was optimized to the criteria of the experiment, resulting in variations of material selection, methods of refrigeration and secondary containment. Collectively, the targets were run for a total of 14,184 hours with an average operational efficiency of 97.6%. The safe and reliable operation of these targets was complemented by an increased degree of documentation and component testing. This operation was also aided by several key upgrades. All the systems were designed and fabricated under a set of written guidelines that blend analytical calculations and empirical guidance drawn from over twenty years of target fabrication experience. 3 refs., 4 tabs.
Date: July 1, 1991
Creator: Allspah, D.; Danes, J.; Peifer, J. & Stanek, R.
Object Type: Article
System: The UNT Digital Library
Inexpensive cross-flow hydropower turbine at Arbuckle Mountain Hydroelectric Project (open access)

Inexpensive cross-flow hydropower turbine at Arbuckle Mountain Hydroelectric Project

This report documents the first three and half years of operation and maintenance on the Arbuckle Mountain Hydroelectric Project. Located on a flashy mountain stream in northern California, the project was designed, built and tested through a Cooperative Agreement between the US DOE and OTT Engineering, Inc. (OTT). The purpose of the Agreement is to build and intensively test an inexpensive American-made cross-flow turbine and to provide information to the DOE on the cost, efficiency, operation, and maintenance of the unit. It requires that OTT document for DOE a summary of the complete operating statistics, operation and maintenance cost, and revenues from power sales for a two-year operating period. Several unique events occurred between the initial start-up (December 1986) and the beginning of the 1989 generation season (October 1988) that delayed the first year's full operation and provided unique information for a demonstration project of this type. Accordingly, this report will discuss certain major problems experienced with the design, operation and maintenance, and energy production, as well as the operation and maintenance costs and value of the power produced for the first three and half years of operation. 9 figs., 2 tabs.
Date: July 1, 1991
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Theory of ordering transformations in metals and minerals (open access)

Theory of ordering transformations in metals and minerals

This dissertation presents an investigation of ordering in FCC based systems using the pair potential approximation in the ground state and mean field limits. The theoretical approach is used to explain the occurrence of observed equilibrium phases and characteristics of thermodynamic instabilities, in particular, spinodal ordering and decomposition. It is shown that the stability of non-integer domain sizes in long period superstructures such as Al{sub 3}Ti and Ag{sub 3}Mg may result from the tendency of a system to reduce the number of non-dominant ordering waves, thus producing domain sizes that have rational fraction form n/m. This conclusion is used to explain the domain size stability with respect to variations in temperature and electron concentration. The cation ordering in the precipitate phases in calcite and dolomite is analyzed by analogy with ordering in FCC based metals. The ordered phases in calcite and dolomite are shown to be consistent with pair potential minima at {l brace}100{r brace} and {l brace}1/2, 1/2, 1/2{r brace} positions in reciprocal space respectively. 32 refs., 6 figs.
Date: July 1, 1991
Creator: Lindsey, Timothy Francis
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device (open access)

Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device

Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system ({rho},{xi}) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number {alpha} as well as the complete EM fields. The computational study involves a multiple …
Date: July 1, 1991
Creator: Peng, S.Y.
Object Type: Report
System: The UNT Digital Library
Ceramic technology for Advanced Heat Engines Project (open access)

Ceramic technology for Advanced Heat Engines Project

Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. This project is managed by ORNL for the Office …
Date: July 1, 1991
Creator: Johnson, D. R.
Object Type: Report
System: The UNT Digital Library
Surface, interface and thin-film magnetism (open access)

Surface, interface and thin-film magnetism

In the last quarter of the 20th century, with the information revolution and the ever growing need to acquire, store, and retrieve information, the science and technologies attached to magnetic recording have experienced an explosive growth. Central to those pursuits has been the materials science of magnetism as it applies to surfaces, interfaces, and thin films. This report discusses topics on thin-film magnetism such as: theory, physical effects, prospects, opportunities and future developments. (JL)
Date: July 1, 1991
Creator: Falicov, L.M. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Physics)
Object Type: Article
System: The UNT Digital Library
A search for the production of the final states. tau. sup +. tau. sup minus e sup + e sup minus ,. tau. sup +. tau. sup minus. mu. sup +. mu. sup minus , and. tau. sup +. tau. sup minus. pi. sup +. pi. sup minus in e sup + e sup minus collisions at radical s = 29 GeV (open access)

A search for the production of the final states. tau. sup +. tau. sup minus e sup + e sup minus ,. tau. sup +. tau. sup minus. mu. sup +. mu. sup minus , and. tau. sup +. tau. sup minus. pi. sup +. pi. sup minus in e sup + e sup minus collisions at radical s = 29 GeV

We have searched for the reaction e{sup +}e{sup {minus}} {yields} {tau}{sup +}{tau}{sup {minus}}{bar f}f, where f is either an electron, muon, or charged pion, at {radical}s = 29 GeV using the Mark 2 detector at the PEP storage ring. One candidate event is found while 2.3 events are expected from known processes. We would expect to see 11 events if the cross-section for e{sup +}e{sup {minus}} {yields} {tau}{sup +}{tau}{sup {minus}}{bar f}f at {radical}s = 29 GeV were enhanced by the factor of 4.7 which the ALEPH collaboration reports for {radical}s = 91 GeV. we also look for e{sup +}e{sup {minus}} {yields} e{sup +}e{sup {minus}}{bar f}f and e{sup +}e{sup {minus}} {yields} {mu}{sup +}{mu}{sup {minus}} {bar f}f, and for e{sup +}e{sup {minus}} {yields} {tau}{sup +}{tau}{sup {minus}} {gamma} using a similar analysis procedure and see the number of events predicted by the standard model. 10 refs., 5 figs., 3 tabs.
Date: July 1, 1991
Creator: unknown
Object Type: Article
System: The UNT Digital Library
Geophysics: Building E5032 decommissioning, Aberdeen Proving Ground (open access)

Geophysics: Building E5032 decommissioning, Aberdeen Proving Ground

integration of data from surveys using three geophysical technologies has provided information used to define the locations of buried utilities, tanks, vaults, and debris near building E5032 at the Aberdeen Proving Ground. Ground penetrating radar (GPR) profiles indicate the presence of buried pipes, tanks, reinforcement rods (rebar), and remnants of railroad tracks. A magnetic map constructed from a detailed magnetic survey on the north side of the building outlines buried iron-rich objects that are interpreted to be iron pipes, tank, and other debris of uncertain origin at relatively shallow depths. Horizontal electrical resistivity surveys and vertical electrical resistivity soundings essentially corroborated the findings obtained with the magnetometer and GPR. In addition, a highly resistance layer was observed on the east side of the building where a former railroad bed with a thick grave fill is believed to immediately underlie the lawn. The resistivity data show no evidence of a conductive leachate plume. Geophysical measurements from three techniques over a buried concrete slab approximately 130 ft north of Building E5032 give geophysical signatures interpreted to be due to the presence of a large iron tank or vault. An attempt was made to gather meaningful magnetic data on the east, west, and …
Date: July 1, 1991
Creator: McGinnis, L.D. & Miller, S.F.
Object Type: Report
System: The UNT Digital Library
Influences of clouds and rain on the large-scale transport and deposition of sulfur (open access)

Influences of clouds and rain on the large-scale transport and deposition of sulfur

This paper describes the application of a three-dimensional, global-scale Eulerian model with an explicit description of cloud and chemical processes. Simulation results describing the transport of sulfur from North America and Europe across the north Atlantic Ocean during a climatological July are presented. Wet deposition was found to contribute slightly more to total sulfur deposition than dry deposition, a feature explained by the large amounts of precipitation during this month. The wet deposition patterns did not always correspond to the emissions patterns. The precipitation rate and spatial distribution had a large effect on the calculated concentrations of soluble sulfur species. 10 refs., 7 figs., 1 tab.
Date: July 1, 1991
Creator: Luecken, D.J.; Berkowitz, C.M. & Easter, R.C.
Object Type: Article
System: The UNT Digital Library
Two-dimensional nuclear magnetic resonance studies of molecular structure in liquids and liquid crystals (open access)

Two-dimensional nuclear magnetic resonance studies of molecular structure in liquids and liquid crystals

Magnetic couplings between protons, such as through-space dipole couplings, and scalar J-couplings depend sensitively on the structure of the molecule. Two dimensional nuclear magnetic resonance experiments provide a powerful tool for measuring these couplings, correlating them to specific pairs of protons within the molecule, and calculating the structure. This work discusses the development of NMR methods for examining two such classes of problems -- determination of the secondary structure of flexible molecules in anisotropic solutions, and primary structure of large biomolecules in aqueous solutions. 201 refs., 84 figs., 19 tabs.
Date: July 1, 1991
Creator: Rucker, S.P.
Object Type: Report
System: The UNT Digital Library
Nonlinear spectroscopic studies of interfacial molecular ordering (open access)

Nonlinear spectroscopic studies of interfacial molecular ordering

The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful new probes of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the nonlinear susceptibility. In particular, infrared-visible sum frequency generation (SFG) can obtain the vibrational spectrum of sub-monolayer coverages of molecules. In this thesis, we explore the unique information that can be obtained from SFG. We take advantage of the sensitivity of SFG to the conformation of alkane chains to study the interaction between adsorbed liquid crystal molecules and surfactant treated surfaces. The sign of the SFG susceptibility depends on the sign of the molecular polarizability and the orientation, up or down, of the molecule. We experimentally determine the sign of the susceptibility and use it to determine the absolute orientation to obtain the sign of the molecular polarizability and show that this quantity contains important information about the dynamics of molecular charge distributions. Finally, we study the vibrational spectra and the molecular orientation at the pure liquid/vapor interface of methanol and water and present the most detailed evidence yet obtained for the structure of the pure water surface. 32 refs., 4 figs., 2 tabs.
Date: July 1, 1991
Creator: Superfine, R.
Object Type: Report
System: The UNT Digital Library
Situational simulations in interactive video (open access)

Situational simulations in interactive video

The Westinghouse Hanford Company Advanced Training Technologies section is using situational simulations in several Interactive Video training courses. Two applications of situational simulations will be discussed. In the first, used in the Hanford General Employee Training course, the student evaluates employee's actions in simulations of possible workplace situations. In the second, used in the Criticality Safety course, students must follow well-defined procedures to complete tasks. Design and incorporation of situational simulations will be discussed. 3 refs.
Date: July 1, 1991
Creator: Smith, L.J.
Object Type: Article
System: The UNT Digital Library
Advanced Coal Conversion Process Demonstration (Project) (open access)

Advanced Coal Conversion Process Demonstration (Project)

This report contains a description of technical progress made on the Advanced Coal Conversion Process Demonstration Project (ACCP). The project is a US Department of Energy Innovative Clean Coal Technology Project. The cooperative agreement defining the project is between DOE and the Rosebud SynCoal Partnership RSCP. The RSCP is a partnership between Western Energy Company (WECo), a subsidiary of Entech, Montana Power's non-utility group, and NRG, a subsidiary of Northern States Power. The ACCP is a method of upgrading low ranked coals by reducing the moisture and sulfur content and increasing the heating value. The facility is being constructed at WECo's Rosebud No. 6 coal mine, west of Colstrip, Montana. This report contains both a history of the process development and a report of technical progress made since the beginning of the Clean Coal 1 cooperative agreement.
Date: July 1, 1991
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Novel nanodispersed coal liquefaction catalysts: Molecular design via microemulsion-based synthesis (open access)

Novel nanodispersed coal liquefaction catalysts: Molecular design via microemulsion-based synthesis

The objective of this project is to pursue the development of highly dispersed and inexpensive catalysts for improved coal solubilization and upgrading of coal liquids. A novel study of the synthesis of liquefaction catalysts of nanometer size will be carried out. It is based on the molecular design of reverse micelles (microemulsions). These surfactant-stabilized, metal-bearing microdrops offer unique opportunities for synthesizing very small particles by providing a cage-like effect that limits particle nucleation, growth and agglomeration. The emphasis will be on iron- and molybdenum-based catalysts, but the techniques to be developed should also be generally applicable. (VC)
Date: July 1, 1991
Creator: Osseo-Asare, K. & Radovic, L.R.
Object Type: Report
System: The UNT Digital Library
On a quasi-isochronous B Factory in the PEP tunnel (open access)

On a quasi-isochronous B Factory in the PEP tunnel

Isochronous, or quasi-isochronous storage rings with very small momentum compaction factor {alpha} for various applications are discussed. This approach looks very promising for the B-Factory design. A small momentum compaction factor reduces the bunch length at the given RF voltage. A small bunch length allows, in principle, reduction of the beta function at the interaction point (IP) with a corresponding increase of the luminosity. However, achieving this is not easy due to difficulties with local chromatic effects at the IP, more severe background problems in the detector, and enhanced adverse effects of the beam-beam interaction. Although these problems can be addressed, they require substantial changes in the present design. It is worth noting that shorter bunches would also have larger energy losses and larger energy spread, due to wake field excitation and the smaller disruption parameter reducing the enhancement factor. But energy losses scale with the bunch length {sigma}{sub z} as {sigma}{sub z}{sup {minus}{1/2}}, remaining small compared with the losses due to synchrotron radiation. The disruption parameter is small in the present design anyway; hence, these effects do not cause additional problems.
Date: July 1, 1991
Creator: Heifets, S.
Object Type: Report
System: The UNT Digital Library
Installation restoration program: Hydrologic measurements with an estimated hydrologic budget for the Joliet Army Ammunition Plant, Joliet, Illinois. [Contains maps of monitoring well locations, topography and hydrologic basins] (open access)

Installation restoration program: Hydrologic measurements with an estimated hydrologic budget for the Joliet Army Ammunition Plant, Joliet, Illinois. [Contains maps of monitoring well locations, topography and hydrologic basins]

Hydrologic data were gathered from the 36.8-mi{sup 2} Joliet Army Ammunition Plant (JAAP) located in Joliet, Illinois. Surface water levels were measured continuously, and groundwater levels were measured monthly. The resulting information was entered into a database that could be used as part of numerical flow model validation for the site. Deep sandstone aquifers supply much of the water in the JAAP region. These aquifers are successively overlain by confining shales and a dolomite aquifer of Silurian age. This last unit is unconformably overlain by Pleistocene glacial tills and outwash sand and gravel. Groundwater levels in the shallow glacial system fluctuate widely, with one well completed in an upland fluctuating more than 17 ft during the study period. The response to groundwater recharge in the underlying Silurian dolomite is slower. In the upland recharge areas, increased groundwater levels were observed; in the lowland discharge areas, groundwater levels decreased during the study period. The decreases are postulated to be a lag effect related to a 1988 drought. These observations show that fluid at the JAAP is not steady-state, either on a monthly or an annual basis. Hydrologic budgets were estimated for the two principal surface water basins at the JAAP site. …
Date: July 1, 1991
Creator: Diodato, D. M.; Cho, H. E. & Sundell, R. C.
Object Type: Report
System: The UNT Digital Library
HEATING 7. 1 user's manual (open access)

HEATING 7. 1 user's manual

HEATING is a FORTRAN program designed to solve steady-state and/or transient heat conduction problems in one-, two-, or three- dimensional Cartesian, cylindrical, or spherical coordinates. A model may include multiple materials, and the thermal conductivity, density, and specific heat of each material may be both time- and temperature-dependent. The thermal conductivity may be anisotropic. Materials may undergo change of phase. Thermal properties of materials may be input or may be extracted from a material properties library. Heating generation rates may be dependent on time, temperature, and position, and boundary temperatures may be time- and position-dependent. The boundary conditions, which may be surface-to-boundary or surface-to-surface, may be specified temperatures or any combination of prescribed heat flux, forced convection, natural convection, and radiation. The boundary condition parameters may be time- and/or temperature-dependent. General graybody radiation problems may be modeled with user-defined factors for radiant exchange. The mesh spacing may be variable along each axis. HEATING is variably dimensioned and utilizes free-form input. Three steady-state solution techniques are available: point-successive-overrelaxation iterative method with extrapolation, direct-solution (for one-dimensional or two-dimensional problems), and conjugate gradient. Transient problems may be solved using one of several finite-difference schemes: Crank-Nicolson implicit, Classical Implicit Procedure (CIP), Classical Explicit Procedure …
Date: July 1, 1991
Creator: Childs, K.W.
Object Type: Report
System: The UNT Digital Library
The Soviet applied information sciences in a time of change (open access)

The Soviet applied information sciences in a time of change

The Foreign Applied Sciences Assessment Center (FASAC) conducts reviews of selected areas of foreign basic and applied science by US scientists who are technically expert and active in the fields reviewed. Several of the FASAC assessments of Soviet science have involved various aspects of the information sciences, including enabling technologies and applications, as well as the core information sciences. This report draws upon those FASAC assessment reports, the expert judgment of some of the authors of those reports, and other public sources to characterize the current state of the information sciences in the Soviet Union and the effects of information science capabilities upon other areas of Soviet science and technology. This report also provides estimates of the likely effect of the political and social reforms underway in the Soviet Union on future Soviet progress in the information sciences and, at a more general level, in science and technology. 41 refs., 7 tabs.
Date: July 1, 1991
Creator: Bengston, J.; Cronin, R. R. & Davidson, R. B.
Object Type: Report
System: The UNT Digital Library
Guidelines for strategic planning (open access)

Guidelines for strategic planning

Strategic planning needs to be done as one of the integral steps in fulfilling our overall Departmental mission. The role of strategic planning is to assure that the longer term destinations, goals, and objectives which the programs and activities of the Department are striving towards are the best we can envision today so that our courses can then be set to move in those directions. Strategic planning will assist the Secretary, Deputy Secretary, and Under Secretary in setting the long-term directions and policies for the Department and in making final decisions on near-term priorities and resource allocations. It will assist program developers and implementors by providing the necessary guidance for multi-year program plans and budgets. It is one of the essential steps in the secretary's Strategic Planning Initiative. The operational planning most of us are so familiar with deals with how to get things done and with the resources needed (people, money, facilities, time) to carry out tasks. Operating plans like budgets, capital line item projects, R D budgets, project proposals, etc., are vital to the mission of the Department. They deal, however, with how to carry out programs to achieve some objective or budget assumption. Strategic planning deals with …
Date: July 1, 1991
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Soft and hard pomerons: Is there a distinction (open access)

Soft and hard pomerons: Is there a distinction

One of the big unsolved problems of QCD remains the problem of the Pomeron: what is the relation of high energy elastic and diffractive phenomena to the underlying theory This is not a subject in which I have actively worked. But my interest in it has in this year increased greatly. The reason has to do with ideas for experimentation at SSC/LHC which either directly address the problem or which require the understanding of strong-interaction diffractive phenomena as backgrounds for discovery-physics processes involving electroweak boson exchanges. I will in this talk omit these motivations, which can be found elsewhere, and instead concentrate on some personal veiwpoints regarding the Pomeron which may or may not be conventional. The main question has to do with the distinction between the original, old-fashioned soft'' Pomeron of the 1960s, built out of multiperipheral hadron-exchanges, and the more modern perturbative-QCD hard'' Pomeron, built out of multiperipheral gluon exchanges. The perspective I offer comes mainly from two sources: one is heavy-flavor physics, and the other is the Manohar-Georgi view of constituent quark physics. 27 refs., 5 figs.
Date: July 1, 1991
Creator: Bjorken, J. D.
Object Type: Article
System: The UNT Digital Library
Fast-neutron total and scattering cross sections of sup 58 Ni and nuclear models (open access)

Fast-neutron total and scattering cross sections of sup 58 Ni and nuclear models

The neutron total cross sections of {sup 58}Ni were measured from {approx} 1 to > 10 MeV using white-source techniques. Differential neutron elastic-scattering cross sections were measured from {approx} 4.5 to 10 MeV at {approx} 0.5 MeV intervals with {ge} 75 differential values per distribution. Differential neutron inelastic-scattering cross sections were measured, corresponding to fourteen levels with excitations up to 4.8 MeV. The measured results, combined with relevant values available in the literature, were interpreted in terms of optical-statistical and coupled-channels model using both vibrational and rotational coupling schemes. The physical implications of the experimental results nd their interpretation are discussed in the contexts of optical-statistical, dispersive-optical, and coupled-channels models. 61 refs.
Date: July 1, 1991
Creator: Smith, A. B.; Guenther, P. T.; Whalen, J. F. (Argonne National Lab., IL (United States)) & Chiba, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment)
Object Type: Report
System: The UNT Digital Library
Historical overview of domestic spent fuel shipments: Update (open access)

Historical overview of domestic spent fuel shipments: Update

This report presents available historic data on most commercial and research reactor spent fuel shipments in the United States from 1964 through 1989. Data include sources of the spent fuel shipped, types of shipping casks used, number of fuel assemblies shipped, and number of shipments made. This report also addresses the shipment of spent research reactor fuel. These shipments have not been documented as well as commercial power reactor spent fuel shipment activity. Available data indicate that the greatest number of research reactor fuel shipments occurred in 1986. The largest campaigns in 1986 were from the Brookhaven National Laboratory, Brooklyn, New York, to the Idaho Chemical Processing Plant (ICPP) and from the Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR) in Tennessee and the Rockwell International Reactor in California to the Savannah River Plant near Aiken, South Carolina. For all years addressed in this report, DOE facilities in Idaho Falls and Savannah River were the major recipients of research reactor spent fuel. In 1989, 10 shipments were received at the Idaho facilities. These originated from universities in California, Michigan, and Missouri. 9 refs., 12 figs., 7 tabs.
Date: July 1, 1991
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Molecular biology of Lea genes of higher plants (open access)

Molecular biology of Lea genes of higher plants

This report contains our progress to date in determining the function of the D-7 Lea proteins in cotton embryos. We have completely sequenced the D-7 gene and established {ital E. coli} transformants which synthesize reasonable amounts of the D-7 protein. Two-dimensional electrophoresis was required to assay fractions for D-7 protein during purification to homogeneity, since D-7 has no known enzymatic activity, contains no Trp, and little Phe or Tyr, and {ital E. coli} has several proteins of similar molecular weight to D-7. Purified D-7 was used to generate monospecific antibodies which are being used for determination of the cellular distribution of D-7, and also for exact quantitation of D-7 in late-stage cotton embryos. Computerized modelling of D-7 has shown similarities to proteins with a coiled-coil structure, but fitting D-7 to this structure resulted in a violation of the handedness rule. If the pitch of the helix is changed from 3.6 to 3.667, however, a three dimensional structure (not a coiled coil) is generated which has overall energetics of formation nearly as favorable as the traditional {alpha} helix. The driving force for the change in pitch is proposed to result from favorable energetics of dimerization. Preliminary evidence indicates that D-7 does …
Date: July 1, 1991
Creator: unknown
Object Type: Report
System: The UNT Digital Library
High poloidal beta equilibria in TFTR limited by a natural inboard poloidal field null (open access)

High poloidal beta equilibria in TFTR limited by a natural inboard poloidal field null

Recent operation of the Tokamak Fusion Test Reactor TFTR, has produced plasma equilibria with values of {Lambda} {triple bond} {beta}{sub p eq} + l{sub i}/2 as large as 7, {epsilon}{beta}{sub p dia} {triple bond} 2{mu}{sub 0}{epsilon}<p{perpendicular}>/{much lt}B{sub p}{much gt}{sup 2} as large as 1.6, and Troyon normalized diamagnetic beta, {beta}{sub N dia} {triple bond} 10{sup 8}<{beta}{sub t}{perpendicular}>aB{sub 0}/I{sub p} as large as 4.7. When {epsilon}{beta}{sub p dia} {approx gt} 1.25, a separatrix entered the vacuum chamber, producing a naturally diverted discharge which was sustained for many energy confinement times, {tau}{sub E}. The largest values of {epsilon}{beta}{sub p} and plasma stored energy were obtained when the plasma current was ramped down prior to neutral beam injection. The measured peak ion and electron temperatures were as large as 24 keV and 8.5 keV, respectively. Plasma stored energy in excess of 2.5 MJ and {tau}{sub E} greater than 130 msec were obtained. Confinement times of greater than 3 times that expected from L-mode predictions have been achieved. The fusion power gain. Q{sub DD}, reached a values of 1.3 {times} 10{sup {minus}3} in a discharge with I{sub p} = 1 MA and {epsilon}{beta}{sub p dia} = 0.85. A large, sustained negative loop voltage during …
Date: July 1, 1991
Creator: Sabbagh, S. A.; Gross, R. A.; Mauel, M. E.; Navratil, G. A. (Columbia Univ., New York, NY (United States). Dept. of Applied Physics); Bell, M. G.; Bell, R. et al.
Object Type: Report
System: The UNT Digital Library