26 Matching Results

Search Results

Advanced search parameters have been applied.

Diffusion of energy-efficient technologies in industry. Final report

Description: United States energy policies aim at cutting down dependence on foreign oil in two ways: by energy conservation and by finding new domestic supplies. The study investigates how the first goal can be achieved in the industrial sector (manufacturing) of the economy, which accounts for about 40% (about 7.3 million barrels per day) of the total energy consumption in the US. It is noted that industry is able to conserve as much as 25 to 30% of its energy consumption by adopting simple conservation measures and energy-efficient technologies. These technologies can be implemented without major alterations of the original equipment. The schools of thought on innovative processes are discussed; these will serve as the conceptual and methodological base of the project. (MCW)
Date: January 1, 1979
Creator: Hsu, S.Y.
Partner: UNT Libraries Government Documents Department

[Project Summary: Effects of Offshore Emissions on Ambient Levels of Atmospheric SO2 at Breton Sound, LA]

Description: Summary describing the work completed at the Coastal Studies Institute for the Effects of Offshore Emissions on Ambient Levels of Atmospheric SO2 at Breton Sound, Louisiana. It includes background information on the project funding and sponsorship, goals, methodology, and findings.
Date: March 1995
Creator: Coastal Studies Institute
Partner: UNT Libraries Government Documents Department

[Project Summary: Air Quality and Dispersion Meteorology over the Northeastern Gulf of Mexico: Measurements, Analyses, and Syntheses]

Description: Summary describing the work completed at Coastal Studies Institute for "Air Quality and Dispersion Meteorology over the Northeastern Gulf of Mexico: Measurements, Analyses, and Syntheses." It includes background information on the project funding and sponsorship, goals, methodology, and findings.
Date: March 2000
Creator: Coastal Studies Institute
Partner: UNT Libraries Government Documents Department

Experimental study of ion heating and acceleration during magnetic reconnection

Description: This dissertation reports an experimental study of ion heating and acceleration during magnetic reconnection, which is the annihilation and topological rearrangement of magnetic flux in a conductive plasma. Reconnection is invoked often to explain particle heating and acceleration in both laboratory and naturally occurring plasmas. However, a simultaneous account of reconnection and its associated energy conversion has been elusive due to the extreme inaccessibility of reconnection events, e.g. in the solar corona, the Earth's magnetosphere, or in fusion research plasmas. Experiments for this work were conducted on MRX (Magnetic Reconnection Experiment), which creates a plasma environment allowing the reconnection process to be isolated, reproduced, and diagnosed in detail. Key findings of this work are the identification of local ion heating during magnetic reconnection and the determination that non-classical effects must provide the heating mechanism. Measured ion flows are sub-Alfvenic and can provide only slight viscous heating, and classical ion-electron interactions can be neglected due to the very long energy equipartition time. The plasma resistivity in the reconnection layer is seen to be enhanced over the classical value, and the ion heating is observed to scale with the enhancement factor, suggesting a relationship between the magnetic energy dissipation mechanism and the ion heating mechanism. The observation of non-classical ion heating during reconnection has significant implications for understanding the role played by non-classical dissipation mechanisms in generating fast reconnection. The findings are relevant for many areas of space and laboratory plasma research, a prime example being the currently unsolved problem of solar coronal heating. In the process of performing this work, local measurements of ion temperature and flows in a well-characterized reconnection layer were obtained for the first time in either laboratory or observational reconnection research. Furthermore, much progress was made in understanding the reconnection process itself.
Date: January 28, 2000
Creator: Hsu, S.C.
Partner: UNT Libraries Government Documents Department

Analysis of Ambient Pollutant Concentrations and Meteorological Conditions Affecting EPA Class I and II Areas in Southeastern Louisiana, Volume 2: Appendices

Description: Appendices containing data that was collected as apart of a study on pollutants in Southeastern Louisiana. The four appendices include: [A] Gosier Island Hourly Data, [B] Breton Island (Chandeleur Islander) Hourly Data, [C] Pass-A-Loutre Hourly Data, and [D] Radiosonde Data.
Date: December 1996
Creator: Hsu, S. A.
Partner: UNT Libraries Government Documents Department

Advanced lubrication systems and materials. Final report

Description: This report described the work conducted at the National Institute of Standards and Technology under an interagency agreement signed in September 1992 between DOE and NIST for 5 years. The interagency agreement envisions continual funding from DOE to support the development of fuel efficient, low emission engine technologies in terms of lubrication, friction, and wear control encountered in the development of advanced transportation technologies. However, in 1994, the DOE office of transportation technologies was reorganized and the tribology program was dissolved. The work at NIST therefore continued at a low level without further funding from DOE. The work continued to support transportation technologies in the development of fuel efficient, low emission engine development. Under this program, significant progress has been made in advancing the state of the art of lubrication technology for advanced engine research and development. Some of the highlights are: (1) developed an advanced high temperature liquid lubricant capable of sustaining high temperatures in a prototype heat engine; (2) developed a novel liquid lubricant which potentially could lower the emission of heavy duty diesel engines; (3) developed lubricant chemistries for ceramics used in the heat engines; (4) developed application maps for ceramic lubricant chemistry combinations for design purpose; and (5) developed novel test methods to screen lubricant chemistries for automotive air-conditioning compressors lubricated by R-134a (Freon substitute). Most of these findings have been reported to the DOE program office through Argonne National Laboratory who manages the overall program. A list of those reports and a copy of the report submitted to the Argonne National Laboratory is attached in Appendix A. Additional reports have also been submitted separately to DOE program managers. These are attached in Appendix B.
Date: May 7, 1998
Creator: Hsu, S.
Partner: UNT Libraries Government Documents Department

Formation of Lubricating Films at Elevated Temperatures from the Gas Phase

Description: Abstract: Conventional liquid lubricants, when subjected to temperatures of 250*C and above for extended time in an air atmosphere, degrade rapidly to make large amounts of solid sludge and deposits. Based on boundary lubrication of bearings, these same lubricants, when subjected to 250*C to the melting point of the bearing metal, produce in the micro- to milli-second residence time in the bearing contact enough "friction polymer" to result in good lubrication. This report describes the use of these conventional liquid lubricants delivered in a homogeneous vapor phase where the carrier gas is nitrogen, air or mixtures of these two gases. The lubricants studied include alkyl and aryl phosphate esters, organic acid esters, polyphenyl ethers, and mineral oil.
Date: September 1988
Creator: Klaus, E. Erwin; Duda, J. L.; Naidu, S. K.; Munro, R. G. & Hsu, S. M.
Partner: UNT Libraries Government Documents Department

Magnetic Reconnection with Sweet-Parker Characteristics in Two-dimensional Laboratory Plasmas

Description: Magnetic reconnection has been experimentally studied in a well-controlled, two-dimensional laboratory magnetohydrodynamic plasma. The observations are found to be both qualitatively and quantitatively consistent with a generalized Sweet-Parker model which incorporates compressibility, downstream pressure, and the effective resistivity. The latter is significantly enhanced over its classical values in the collisionless limit. This generalized Sweet-Parker model also applies to the case in which an unidirectional, sizable third magnetic component is present.
Date: January 1, 1999
Creator: Carter, T.; Hsu, S.; Ji, H.; Kulsrud, R.; Yamada, M. & al, et
Partner: UNT Libraries Government Documents Department

Experimental Investigation of the Neutral sheet Profile During Magnetic Reconnection

Description: During magnetic reconnection, a ''neutral sheet'' current is induced, heating the plasma. The resultant plasma thermal pressure forms a stationary equilibrium with the opposing magnetic fields. The reconnection layer profile holds significant clues about the physical mechanisms which control reconnection. On the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)], a quasi steady-state and axisymmetric neutral sheet profile has been measured precisely using a magnetic probe array with spatial resolution equal to one quarter of the ion gyro-radius. It was found that the reconnecting field profile fits well with a Harris-type profile [E. G. Harris, Il Nuovo Cimento 23, 115 (1962)], B(x) approximately tanh(x/delta). This agreement is remarkable since the Harris theory does not take into account reconnection and associated electric fields and dissipation. An explanation for this agreement is presented. The sheet thickness delta is found to be approximately 0.4 times the ion skin depth, which agrees with a generalized Harris theory incorporating non-isothermal electron and ion temperatures and finite electric field. The detailed study of additional local features of the reconnection region is also presented.
Date: November 1, 1999
Creator: Trintchouk, F.; Ji, H.; Yamada, M.; Kulsrud, R.; Hsu, S. & Carter, T.
Partner: UNT Libraries Government Documents Department

Topics in particle physics and cosmology

Description: The Standard Model of particle physics, together with the Big Bang model of the early universe, constitute a framework which encompasses our current understanding of fundamental laws and beginning of our universe. Despite recent speculative trends, quantum field theory remains the theoretical tool of choice for investigating new physics either at high energy colliders, or in the early universe. In this dissertation, several field theoretic phenomena relevant to cosmology or particle physics are explored. A common theme in these explorations is the structure of the vacuum state in quantum field theory. First, we discuss first-order phase transitions in the early universe, in which the effective vacuum state of the universe shifts discontinuously as the temperature drops below some critical point. We find that the dynamics of a certain type of first-order phase transition can lead to production of primordial black holes, which could constitute the dark matter of our universe. Alternatively, supercooled first-order phase transitions may be the cause of an extended inflationary epoch in the early universe, which is generally regarded as necessary to solve several cosmological puzzles. We derive limits on such scenarios based on nearly model-independent percolation properties of the transition. We also study some nonperturbative aspects of the field theory vacuum. We show that non-topological solitons of a single fermion and Higgs fields can only exist in strongly coupled theories. In particular, we find that at the lowest fermionic excitations in the Standard Model are single fermions, and not bound states of fermion plugs Higgs. Finally, we investigate the intriguing behavior of instanton-induced cross sections. We discover Higgs-Higgs cross sections which increase exponentially with center of mass energy due to the presence of instanton solutions related to vacuum instability.
Date: August 2, 1991
Creator: Hsu, S.D.H.
Partner: UNT Libraries Government Documents Department

Experimental Study of Ion Heating and Acceleration During Magnetic Reconnection

Description: Ion heating and acceleration has been studied in the well-characterized reconnection layer of the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)]. Ion temperature in the layer rises substantially during null-helicity reconnection in which reconnecting field lines are anti-parallel. The plasma out flow is sub-Alfvonic due to a downstream back pressure. An ion energy balance calculation based on the data and including classical viscous heating indicates that the ions are heated largely due to non-classical mechanisms. The Ti rise is much smaller during co-helicity reconnection in which field lines reconnect obliquely. This is consistent with a slower reconnection rate and a smaller resistivity enhancement over the Spitzer value. These observations indicate strongly that non-classical dissipation mechanisms can play an important role both in heating the ions and in facilitating the reconnection process.
Date: October 24, 2000
Creator: Hsu, S.C.; Carter, T.A.; Fiksel, G.; Ji, H.; Kulsrud, R.M. & Yamada, M.
Partner: UNT Libraries Government Documents Department

Local Measurement of Non-Classical Ion Heating During Magnetic Reconnection

Description: Local ion temperature is measured directly in the well-characterized reconnection layer of a laboratory plasma. These measurements demonstrate definitively that ions are heated due to reconnection and that more than half of the reconnected field energy is converted to ion kinetic energy. Neither classical Ohmic dissipation nor thermalization of energetic flows is sufficient to account for the energy converted, suggesting the importance of non-classical dissipation mechanisms such as wave-particle interactions.
Date: November 1, 1999
Creator: Fiskel, G.; Ji, H.; Yamada, M.; Kulsrud, R.M.; Hsu, S.C. & Carter, T.A.
Partner: UNT Libraries Government Documents Department

Stress analysis of closure bolts for shipping casks

Description: This report specifies the requirements and criteria for stress analysis of closure bolts for shipping casks containing nuclear spent fuels or high level radioactive materials. The specification is based on existing information conceming the structural behavior, analysis, and design of bolted joints. The approach taken was to extend the ASME Boiler and Pressure Vessel Code requirements and criteria for bolting analysis of nuclear piping and pressure vessels to include the appropriate design and load characteristics of the shipping cask. The characteristics considered are large, flat, closure lids with metal-to-metal contact within the bolted joint; significant temperature and impact loads; and possible prying and bending effects. Specific formulas and procedures developed apply to the bolt stress analysis of a circular, flat, bolted closure. The report also includes critical load cases and desirable design practices for the bolted closure, an in-depth review of the structural behavior of bolted joints, and a comprehensive bibliography of current information on bolted joints.
Date: January 1, 1993
Creator: Mok, G.C.; Fischer, L.E. (Lawrence Livermore National Lab., CA (United States)) & Hsu, S.T. (Kaiser Engineers, Oakland, CA (United States))
Partner: UNT Libraries Government Documents Department

COMMISSIONING OF THE DIGITAL TRANSVERSE BUNCH-BY-BUNCH FEEDBACK SYSTEM FOR THE TLS.

Description: Multi-bunch instabilities degrade beam quality through increased beam emittance, energy spread and even beam loss. Feedback systems are used to suppress multi-bunch instabilities associated with the resistive wall of the beam ducts, cavity-like structures, and trapped ions. A new digital transverse bunch-by-bunch feedback system has recently been commissioned at the Taiwan Light Source, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance and improves damping for transverse instability at high currents, such that top-up operation is achieved. After a coupled-bunch transverse instability was suppressed, more than 350 mA was successfully stored during preliminary commissioning. In this new system, a single feedback loop simultaneously suppresses both horizontal and vertical multi-bunch instabilities. Investigating the characteristics of the feedback loop and further improving the system performances are the next short-term goals. The feedback system employs the latest generation of field-programmable gate array (FPGA) processor to process bunch signals. Memory has been installed to capture up to 250 msec of bunch oscillation signal, considering system diagnostics suitable to support various beam physics studies.
Date: June 26, 2006
Creator: HU, K.H.; KUO, C.H.; CHOU, P.J.; LEE, D.; HSU, S.Y.; CHEN, J. et al.
Partner: UNT Libraries Government Documents Department

Identification of Y-shaped and O-shaped diffusion regions during magnetic reconnection in a laboratory plasma

Description: Two strikingly different shapes of diffusion regions are identified during magnetic reconnection in a magnetohydrodynamic laboratory plasma. The shapes depend on the third vector component of the reconnecting magnetic fields. Without the third component (anti-parallel or null-helicity reconnection), a thin double-Y shaped diffusion region is identified. In this case, the neutral sheet current profile is accurately measured to be as narrow as the order of the ion gyro-radius. In the presence of an appreciable third component (co-helicity reconnection), an O-shaped diffusion region appears and grows into a spheromak configuration.
Date: April 1, 1997
Creator: Yamada, Masaaki; Ji, H.; Hsu, S.; Carter, T.; Kulsrud, R.; Ono, Yasushi et al.
Partner: UNT Libraries Government Documents Department

Experimental Test of the Sweet-Parker Model of Magnetic Reconnection

Description: We report a quantitative experimental test of the Sweet-Parker model of magnetic reconnection in a controlled laboratory plasma. It is found that the observed reconnection rate cannot be explained by the Sweet-Parker model unless the model is generalized to incorporate compressibility, downstream pressure, and the effective resistivity. The latter is significantly enhanced over its classical values in the collisionless limit.
Date: October 3, 1997
Creator: Ji, Hantao; Yamada, Masaaki; Hsu, S. & Kulsrud, R.
Partner: UNT Libraries Government Documents Department

Study of driven magnetic reconnection in a laboratory plasma

Description: The Magnetic Reconnection Experiment (MRX) has been constructed to investigate the fundamental physics of magnetic reconnection in a well controlled laboratory setting. This device creates an environment satisfying the criteria for a magnetohydrodynamic (MHD) plasma (S {much_gt} 1, {rho}{sub i} {much_lt} L). The boundary conditions can be controlled externally, and experiments with fully three-dimensional reconnection are now possible. In the initial experiments, the effects of the third vector component of reconnecting fields have been studied. Two distinctively different shapes of neutral sheet current layers, depending on the third component, are identified during driven magnetic reconnection. Without the third component (anti-parallel or null-helicity reconnection), a thin double-Y shaped diffusion region is identified. A neutral sheet current profile is measured accurately to be as narrow as order ion gyro-radius. In the presence of an appreciable third component (co-helicity reconnection), an O-shaped diffusion region appears and grows into a spheromak configuration.
Date: December 31, 1998
Creator: Yamada, Masaaki; Ji, H.; Hsu, S.; Carter, T.; Kulsrud, R.; Bretz, N. et al.
Partner: UNT Libraries Government Documents Department