Non-linear instability of DIII-D to error fields (open access)

Non-linear instability of DIII-D to error fields

Otherwise stable DIII-D discharges can become nonlinearly unstable to locked modes and disrupt when subjected to resonant m = 2, n = 1 error field caused by irregular poloidal field coils, i.e. intrinsic field errors. Instability is observed in DIII-D when the magnitude of the radial component of the m = 2, n = 1 error field with respect to the toroidal field is B{sub r21}/B{sub T} of about 1.7 {times} 10{sup {minus}4}. The locked modes triggered by an external error field are aligned with the static error field and the plasma fluid rotation ceases as a result of the growth of the mode. The triggered locked modes are the precursors of the subsequent plasma disruption. The use of an n = 1 coil'' to partially cancel intrinsic errors, or to increase them, results in a significantly expanded, or reduced, stable operating parameter space. Precise error field measurements have allowed the design of an improved correction coil for DIII-D, the C-coil'', which could further cancel error fields and help to avoid disruptive locked modes. 6 refs., 4 figs.
Date: October 1, 1991
Creator: La Haye, R. J. & Scoville, J. T.
System: The UNT Digital Library
The neutrinos in muon decay (open access)

The neutrinos in muon decay

We review the available information on the identity of the neutrino states emitted in muon decay, and discuss the exotic decay {mu}{sup +} {yields} e{sup +} {bar {nu}}{sub e}{nu}{sub {mu}}. 22 refs.
Date: October 21, 1991
Creator: Herczeg, P.
System: The UNT Digital Library
A comparison of spanwise aerodynamic loads estimated from measured bending moments versus direct pressure measurements on horizontal axis wind turbine blades (open access)

A comparison of spanwise aerodynamic loads estimated from measured bending moments versus direct pressure measurements on horizontal axis wind turbine blades

Two methods can be used to determine aerodynamic loads on a rotating wind turbine blade. The first is to make direct pressure measurements on the blade surface. This is a difficult process requiring costly pressure instrumentation. The second method uses measured flap bending moments in conjunction with analytical techniques to estimate airloads. This method, called ALEST, was originally developed for use on helicopter rotors and was modified for use on horizontal axis wind turbine blades. Estimating airloads using flap bending moments in much simpler and less costly because measurements can be made with conventional strain gages and equipment. This paper presents results of airload estimates obtained using both methods under a variety of operating conditions. Insights on the limitations and usefulness of the ALEST bending moment technique are also included. 10 refs., 6 figs.
Date: October 1, 1991
Creator: Simms, D A & Butterfield, C P
System: The UNT Digital Library
Tumors of the skin and soft tissues (open access)

Tumors of the skin and soft tissues

The majority of the body surface is covered by the skin. Many internal disorders are reflected in the condition of the skin. One of the major functions of the skin is protection of the other organ systems from a variety of environmental insults. In this role, the skin itself is exposed to factors that can ultimately cause chronic diseases and cancer. Since it is relatively easy to recognize skin abnormalities, most skin cancers are brought to professional attention sooner than other types of cancer. However, due to the close resemblance between many skin neoplasms and noncancerous dermatologic disorders, these neoplasms may be mistreated for months or even years. In veterinary oncology, as in human medicine, most cancers can be effectively treated or cured following an accurate diagnosis. Once diagnosed, skin neoplasms should be aggressively treated. If causal factors are known, exposure to these factors should be limited through removal of the agent (for chemical carcinogens) or limiting exposure to the agent (for other carcinogens such as sunlight). 10 tabs. (MHB)
Date: October 1, 1991
Creator: Weller, R. E.
System: The UNT Digital Library
Future aircraft and potential effects on stratospheric ozone and climate (open access)

Future aircraft and potential effects on stratospheric ozone and climate

The purpose of this study is to extend the recent research examining the global environmental effects from potential fleets of subsonic and supersonic commercial aircraft. Initial studies with LLNL models of global atmospheric chemical, radiative, and transport processes have indicated that substantial decreases in stratospheric ozone concentrations could result from emissions of NO{sub x} from aircraft flying in the stratosphere, depending on fleet size and magnitude of the engine emissions. These studies used homogeneous chemical reaction rates (e.g. gas-phase chemistry). Recent evidence indicates that reactions on particles in the stratosphere may be important. Heterogeneous chemical reactions, for instance, N{sub 2}O{sub 5}and ClONO{sub 2} on background sulfuric acid aerosols, convert NO{sub x}(NO and NO{sub 2}) molecules to HNO{sub 3}. This decreases the odd oxygen loss from the NO{sub x} catalytic cycle and increases the odd oxygen loss from the Cl{sub x} catalytic cycle. By including these heterogeneous reactions in the LLNL model, the relative partitioning of odd oxygen loss between these two families changes, with the result that emissions of NO{sub x} from proposed aircraft fleets flying in the stratosphere now increase zone. Having these heterogeneous processes present also increases ozone concentration in the troposphere relative to gas-phase only chemistry calculations …
Date: October 1, 1991
Creator: Kinnison, D.E. & Wuebbles, D.J.
System: The UNT Digital Library
PNL In Vivo Phantom Library Calibration Program (open access)

PNL In Vivo Phantom Library Calibration Program

None
Date: October 1, 1991
Creator: Olsen, P. C.; Nichols, L. L.; Sisk, D. R. (Pacific Northwest Lab., Richland, WA (United States)) & Loesch, R. M. (USDOE, Washington, DC (United States))
System: The UNT Digital Library
The Advanced Light Source U8 beam line, 20--300 eV (open access)

The Advanced Light Source U8 beam line, 20--300 eV

The U8 is a beam line under construction at the Advanced Light Source (ALS). The beam line will be described along with calculations of its performance and its current status. An 8 cm period undulator is followed by two spherical collecting mirrors, an entrance slit, spherical gratings having a 15{degree} deviation angle, a moveable exit slit, and refocusing and branching mirrors. Internal water cooling is provided to the metal M1 and M2 mirrors as well as to the gratings. Calculations have been made of both the flux output and the resolution over its photon energy range of 20--300 eV. The design goal was to achieve high intensity, 10{sup 12} photons/sec, at a high resolving power of 10,000. The U8 Participating Research Team (PRT) is planning experiments involving the photoelectron spectroscopy of gaseous atoms and molecules, the spectroscopy of ions and actinide spectroscopy.
Date: October 1, 1991
Creator: Heimann, P.; Warwick, T.; Howells, M.; McKinney, W.; Digennaro, D.; Gee, B. et al.
System: The UNT Digital Library
Growth rate of dislocation loop in Fe-Ni-Cr alloy under Kr sup + ion and electron irradiation (open access)

Growth rate of dislocation loop in Fe-Ni-Cr alloy under Kr sup + ion and electron irradiation

In order to examine the effect of irradiating particle species on the growth rate of radiation-induced dislocation loops, a solution-annealed Fe-25Ni-15Cr-0.02C alloy was irradiated at 723 K first by 1.5 MeV Kr{sup +} ions for 2520 sec, then by 1.5 MeV Kr{sup +} ions and 1.0 MeV electrons simultaneously for 780 sec, and finally by 1.0 MeV electrons for 780 sec with the HVEM-Tandem Facility in Argonne National Laboratory. The calculated damage rate by 1.5 MeV Kr{sup +} ions was 5.8 {times} 10{sup {minus}4} dpa/s, and that by 1.0 MeV electrons was 1 {times} 10{sup {minus}4} dpa/s. The growth rate of a dislocation loop located at the center of the specimen was 7 {times} 10{sup {minus}3} nm/s for the Kr{sup +} ion irradiation, 4 {times} 10{sup {minus}2} nm/s for the simultaneous Kr{sup +} and electron irradiation, and (2--3) {times} 10{sup {minus}2} nm/s for the electron irradiation. This implies that the electron irradiation is about 19 times more effective in the growth of radiation-induced dislocation loops than the Kr{sup +} ion irradiation. The dislocation loop growth rate under the simultaneous Kr{sup +} and electron irradiation is higher than the sum of the growth rates under the individual Kr{sup +} and electron …
Date: October 1, 1991
Creator: Kimoto, T. (National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)); Allen, C.W. & Rehn, L.E. (Argonne National Lab., IL (United States))
System: The UNT Digital Library
Hanford Waste Vitrification Plant (open access)

Hanford Waste Vitrification Plant

The Hanford Waste Vitrification Plant (HWVP) is being designed to immobilize pretreated Hanford high-level waste and transuranic waste in borosilicate glass contained in stainless steel canisters. Testing is being conducted in the HWVP Technology Development Project to ensure that adapted technologies are applicable to the candidate Hanford wastes and to generate information for waste form qualification. Empirical modeling is being conducted to define a glass composition range consistent with process and waste form qualification requirements. Laboratory studies are conducted to determine process stream properties, characterize the redox chemistry of the melter feed as a basis for controlling melt foaming and evaluate zeolite sorption materials for process waste treatment. Pilot-scale tests have been performed with simulated melter feed to access filtration for solids removal from process wastes, evaluate vitrification process performance and assess offgas equipment performance. Process equipment construction materials are being selected based on literature review, corrosion testing, and performance in pilot-scale testing. 3 figs., 6 tabs.
Date: October 1, 1991
Creator: Larson, D. E.; Allen, C. R. (Pacific Northwest Lab., Richland, WA (United States)); Kruger, O. L. & Weber, E. T. (Westinghouse Hanford Co., Richland, WA (United States))
System: The UNT Digital Library
Prototype photon position monitors for undulator beams at the Advanced Light Source (open access)

Prototype photon position monitors for undulator beams at the Advanced Light Source

Design criteria are described, and test results are presented, for prototype ALS undulator beam position monitors. The design is based on monitors presently in use at NSLS, with modifications to account for the widely varying and large K values of the undulators to be installed at the ALS. In particular, we have modified the design to simplify the thermal engineering and we have explored techniques to suppress the response of the monitors to soft photons, so that the beam position can be determined by measuring the higher energy photons which are better collimated. 4 refs., 8 figs.
Date: October 17, 1990
Creator: Warwick, T.; Shu, D. (Lawrence Berkeley Lab., CA (United States)); Rodricks, B. (Argonne National Lab., IL (United States)) & Johnson, E.D. (Brookhaven National Lab., Upton, NY (United States))
System: The UNT Digital Library
A measurement of the p p total cross section at radical s = 1800 GeV (open access)

A measurement of the p p total cross section at radical s = 1800 GeV

The {bar p}p differential elastic scattering cross section was measured at {radical}{bar s} = 1800 GeV, using an improved accelerator luminosity determination and CDF small angle data in the range of 0.05 {le} t {le} 0.2(GeV/c){sup 2}. By extrapolating the differential cross sections to t=0 and using the optical theorem we obtain a total cross section of {sigma}{sub tot}({bar p}p) = 72.0 {plus minus} 3.6 mb. This result is preliminary in the sense that we expect to further reduce the systematic error on the optical point. 9 refs., 8 figs.
Date: October 1, 1991
Creator: White, S. (Rockefeller Univ., New York, NY (United States))
System: The UNT Digital Library
Direct electron heating by 60 MHz fast waves on DIII-D (open access)

Direct electron heating by 60 MHz fast waves on DIII-D

Efficient direct electron heating by fast waves has been observed on the DIII-D tokamak. A four strap antenna with (0,{pi},0,{pi}) phasing launched up to 1.6 MW of fast wave power with {vert bar}n{sub {parallel}}{vert bar} {approx} 11. This {vert bar}n{sub {parallel}}{vert bar} is suitable for strong electron interaction in ohmic target plasmas (T{sub e} {le} 2 keV). Ion cyclotron absorption was minimized by keeping the hydrogen fraction low ({lt}3%) in deuterium discharges and by operating at high ion cyclotron harmonics ({omega} = 4{Omega}{sub H} = 8{Omega}{sub D} at 1T). The fast wave electron heating was weak for central electron temperatures below 1 keV, but improved substantially with increasing T{sub e}. Although linear theory predicts a strong inverse magnetic field scaling of the first pass absorption, the measured fast-wave heating efficiency was independent of magnetic field. Multiple pass absorption of the fast waves appears to be occurring since at 2.1 T nearly 100% efficient plasma heating is observed while the calculated first pass absorption is 6% to 8%. The central electron temperature during fast wave heating also increased with magnetic field. The improved electron heating at higher magnetic fields may be due in part to a peaking of the ohmic plasma …
Date: October 1, 1991
Creator: Petty, C. C.; Pinsker, R. I.; Mayberry, M. J.; Chiu, S. C.; Luce, T. C.; Prater, R. (General Atomics, San Diego, CA (United States)) et al.
System: The UNT Digital Library
The electrical insulation of the DIII-D advanced divertor electrode (open access)

The electrical insulation of the DIII-D advanced divertor electrode

The electrode for biasing experiments on the DIII-D tokamak was installed in the summer of 1990 and biasing experiments have shown positive results. For the electrode, electrical insulation had to provide voltage standoff in the DIII-D divertor environment of neutral pressures in the range of 10{sup {minus}8} to 5 {times} 10{sup {minus}2} torr, variable magnetic fields, and in the presence of ionizing radiation. The electrical insulation system was designed and tested in air and vacuum for voltages up to 3 kV. In this paper, we provide an update on our operating experience, problems encountered, and improvements to the system. Electrical breakdown of some components has occurred during tokamak operations and transient voltages, up to 5 kV, have been observed. The original concept for insulating the water and electrical feeds for the electrode, a thin layer of woven ceramic cloth insulation between the feeds and a ground plane to keep out stray plasma, was found to be prone to failure. A new scheme of rigid ceramic insulators surrounded by a ground plane was designed and is being implemented. Another problem was arcs from vessel potential surfaces to the electrode in several locations where vessel ground existed within 1 cm of the …
Date: October 1, 1991
Creator: Smith, J. P.; Schaffer, M. J. & Hyatt, A. W.
System: The UNT Digital Library
Problems in mechanistic theoretical models for cell transformation by ionizing radiation (open access)

Problems in mechanistic theoretical models for cell transformation by ionizing radiation

A mechanistic model based on yields of double strand breaks has been developed to determine the dose response curves for cell transformation frequencies. At its present stage the model is applicable to immortal cell lines and to various qualities (X-rays, Neon and Iron) of ionizing radiation. Presently, we have considered four types of processes which can lead to activation phenomena: (1) point mutation events on a regulatory segment of selected oncogenes, (2) inactivation of suppressor genes, through point mutation, (3) deletion of a suppressor gene by a single track, and (4) deletion of a suppressor gene by two tracks.
Date: October 1, 1991
Creator: Chatterjee, A. & Holley, W. R.
System: The UNT Digital Library
Application of the generic ANSI N13. 30 minimum detectable activity equation to multichannel analysis (open access)

Application of the generic ANSI N13. 30 minimum detectable activity equation to multichannel analysis

This paper addresses the concepts of the decision level (L{sub c}) and the minimum detectable activity (MDA) as they pertain to the interpretation of direct in vivo measurements. The approach is an extension of the methods found in the bioassay performance criteria of the draft ANSI Standard N13.30 Performance Criteria for Radiobioassay.'' 3 refs., 2 tabs.
Date: October 1, 1991
Creator: MacLellan, J. A.; Lynch, T. P. & Rieksts, G. A.
System: The UNT Digital Library
Pattern recognition in gamma-gamma coincidence data sets (open access)

Pattern recognition in gamma-gamma coincidence data sets

Considerable amounts of tedious labor are required to manually scan high-resolution 1D slices of two dimensional {gamma}-{gamma} coincident matrices for relevant and exciting structures. This is particularly true when the interesting structures are of weak intensity. We are working on automated search methods for the detection of rotational band structures in the full 2D space using pattern recognition techniques. For nominal sized data sets (1024{times}1024), however, these techniques only become computationally feasible through the use of Fourier Transform methods. Furthermore the presentation of data matrices as images rather than series of 1D spectra has been shown to be useful. In this paper we will present the data manipulation techniques we have developed.
Date: October 1, 1990
Creator: Manatt, D. R.; Barnes, F. L.; Becker, J. A.; Candy, J. V.; Henry, E. A. (Lawrence Livermore National Lab., CA (United States)) & Brinkman, M. J. (Rutgers--the State Univ., New Brunswick, NJ (United States))
System: The UNT Digital Library
Designation of facility usage categories for Hanford Site facilities (open access)

Designation of facility usage categories for Hanford Site facilities

This report summarizes the Hanford Site methodology used to ensure facility compliance with the natural phenomena design criteria set forth in the US Department of Energy Orders and guidance. The current Hanford Site methodology for Usage Category designation is based on an engineered feature's safety function and on the feature's assigned Safety Class. At the Hanford Site, Safety Class assignments are deterministic in nature and are based on teh consequences of failure, without regard to the likelihood of occurrence. The report also proposes a risk-based approach to Usage Category designation, which is being considered for future application at the Hanford Site. To establish a proper Usage Category designation, the safety analysis and engineering design processes must be coupled. This union produces a common understanding of the safety function(s) to be accomplished by the design feature(s) and a sound basis for the assignment of Usage Categories to the appropriate systems, structures, and components. 4 refs., 9 figs., 1 tab.
Date: October 1, 1991
Creator: Woodrich, D. D.; Ellingson, D. R.; Scott, M. A. & Schade, A. R.
System: The UNT Digital Library
Irradiation testing of a niobium-molybdenum developmental thermocouple (open access)

Irradiation testing of a niobium-molybdenum developmental thermocouple

A need exists for a radiation-resistant thermocouple capable of monitoring temperatures in excess of the limits of the chromel/alumel system. Tungsten/rhenium and platinum/rhodium thermocouples have sufficient temperature capability but have proven to be unstable because of irradiation-induced decalibration. The niobium/molybdenum system is believed to hold great potential for nuclear applications at temperatures up to 2000 K. However, the fragility of pure niobium and fabrication problems with niobium/molybdenum alloys have limited development of this system. Utilizing the Fast Flux Test Facility, a developmental thermocouple with a thermoelement pair consisting of a pure molybdenum and a niobium-1%zirconium alloy wire was irradiated fro 7200 hours at a temperature of 1070 K. The thermocouple performed flawlessly for the duration of the experiment and exhibited stability comparable to a companion chromel/alumel unit. A second thermocouple, operating at 1375 K, is currently being employed to monitor a fusion materials experiment in the Fast Flux Test Facility. This experiment, also scheduled for 7200 hours, will serve to further evaluate the potential of the niobium-1%zirconium/molybdenum thermoelement system. 7 refs., 7 figs.
Date: October 1, 1991
Creator: Knight, R. C. & Greenslade, D. L.
System: The UNT Digital Library
Relating space radiation environments to risk estimates (open access)

Relating space radiation environments to risk estimates

This lecture will provide a bridge from the physical energy or LET spectra as might be calculated in an organ to the risk of carcinogenesis, a particular concern for extended missions to the moon or beyond to Mars. Topics covered will include (1) LET spectra expected from galactic cosmic rays, (2) probabilities that individual cell nuclei in the body will be hit by heavy galactic cosmic ray particles, (3) the conventional methods of calculating risks from a mixed environment of high and low LET radiation, (4) an alternate method which provides certain advantages using fluence-related risk coefficients (risk cross sections), and (5) directions for future research and development of these ideas.
Date: October 1, 1991
Creator: Curtis, S.B.
System: The UNT Digital Library
Jets in hadron colliders at order. alpha. sub s sup 3 (open access)

Jets in hadron colliders at order. alpha. sub s sup 3

Recent results from the study of hadronic jets in hadron-hadron collisions at order a{sub s}{sup 3} in perturbation theory are presented. The numerical results are in good agreement with data and this agreement is illustrated where possible.
Date: October 1, 1991
Creator: Ellis, S.D. (Washington Univ., Seattle, WA (United States). Dept. of Physics); Kunszt, Z. (Eidgenoessische Technische Hochschule, Zurich (Switzerland). Inst. fuer Theoretische Physik) & Soper, D.E. (Oregon Univ., Eugene, OR (United States). Inst. of Theoretical Science)
System: The UNT Digital Library
Resonant enhancement of flavor-changing neutrino interactions (open access)

Resonant enhancement of flavor-changing neutrino interactions

The resonant amplification of neutrino oscillations in the presence of flavor-changing neutrino interactions with matter is analyzed. It is shown that a significant {mu}-flavor conversion can take place even in the absence of neutrino mixing in vacuum. To account for the solar neutrino deficit, the strength of the new interactions should be {approximately} 10{sup {minus}2}G{sub F} and the resulting neutrino suppression and spectrum is similar to that in the ordinary MSW effect. I discuss some extensions of the standard model where these interactions can be present, taking into account the experimental constraints that arise mainly from the induced leptonic rare decays.
Date: October 1, 1991
Creator: Roulet, E.
System: The UNT Digital Library
Computer control of the high-voltage power supply for the DIII-D Electron Cyclotron Heating system (open access)

Computer control of the high-voltage power supply for the DIII-D Electron Cyclotron Heating system

The D3-D Electron Cyclotron Heating (ECH) high voltage power supply is controlled by a computer. Operational control is input via keyboard and mouse, and computer/power supply interface is accomplished with a Computer Assisted Monitoring and Control (CAMAC) system. User-friendly tools allow the design and layout of simulated control panels on the computer screen. Panel controls and indicators can be changed, added or deleted, and simple editing of user-specific processes can quickly modify control and fault logic. Databases can be defined, and control panel functions are easily referred to various data channels. User-specific processes are written and linked using Fortran, to manage control and data acquisition through CAMAC. The resulting control system has significant advantages over the hardware it emulates: changes in logic, layout, and function are quickly and easily incorporated; data storage, retrieval, and processing are flexible and simply accomplished, physical components subject to wear and degradation are minimized. In addition, the system can be expanded to multiplex control of several power supplied, each with its own database, through a single computer and console. 5 refs., 4 figs., 1 tab.
Date: October 1, 1991
Creator: Clow, D. D. & Kellman, D. H.
System: The UNT Digital Library
Recent DIII-D neutral beam calibration results (open access)

Recent DIII-D neutral beam calibration results

Injected DIII-D neutral beam power is estimated based on three principle quantities: the fraction of ion beam that is neutralized in the neutralizer gas cell, the beamline transmission efficiency, and the fraction of beam reionized in the drift duct. System changes in the past few years have included a new gradient grid voltage operating point, ion source arc regulation, routine deuterium operations and new neutralizer gas flow controllers. Additionally, beam diagnostics have been improved and better calibrated. To properly characterize the beams the principle quantities have been re-measured. Two diagnostics are primarily used to measure the quantities. The beamline waterflow calorimetry system measures the neutralization efficiency and the beamline transmission efficiency, and the target tile thermocouples measure the reionization loss. An additional diagnostic, the target tile pyrometer, confirmed the reionization loss measurement. Descriptions and results of these measurements will be presented. 4 refs., 5 figs., 2 tabs.
Date: October 1, 1991
Creator: Wight, J.; Hong, R.M. & Phillips, J.
System: The UNT Digital Library
Principles and major agents in clinical oncology chemotherapy (open access)

Principles and major agents in clinical oncology chemotherapy

This paper provides a brief classification of drugs available for veterinary chemotherapy, as well as justifications for their use. Some common neoplasia and the drugs of choice for their treatment are described. A listing by class of systemic chemotherapeutic agents, their mode of action, tumors responsive to the drugs, precautions and common adverse effects and mode of administration is provided. 2 tabs. (MHB)
Date: October 1, 1991
Creator: Weller, R. E.
System: The UNT Digital Library