Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction. Final technical report, Volume 1 - effects of solvents, catalysts and temperature conditions on conversion and structural changes of low-rank coals (open access)

Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction. Final technical report, Volume 1 - effects of solvents, catalysts and temperature conditions on conversion and structural changes of low-rank coals

The main objectives of this project were to study the effects of low-temperature pretreatments on coal structure and their impacts on subsequent liquefaction. The effects of pretreatment temperatures, catalyst type, coal rank, and influence of solvent were examined. Specific objectives were to identify the basic changes in coal structure induced by catalytic and thermal pretreatments, and to determine the reactivity of the catalytically and thermally treated coals for liquefaction. In the original project management plan it was indicated that six coals would be used for the study. These were to include two each of bituminous, subbituminous, and lignite rank. For convenience in executing the experimental work, two parallel efforts were conducted. The first involved the two lignites and one subbituminous coal; and the second, the two bituminous coals and the remaining subbituminous coal. This Volume presents the results of the first portion of the work, studies on two lignites and one subbituminous coal. The remaining work accomplished under this project will be described and discussed in Volume 2 of this report. The objective of this portion of the project was to determine and compare the effects of solvents, catalysts and reaction conditions on coal liquefaction. Specifically, the improvements of reaction …
Date: January 1, 1998
Creator: Huang, Lili; Schobert, H.H. & Song, Chunshan
System: The UNT Digital Library
Measurement of time dependent B{sub d}{sup 0} {bar B}{sub d}{sup 0} mixing parameter using opposite side lepton and D* meson in p{bar p} collisions at {radical}s = 1.8 TeV (open access)

Measurement of time dependent B{sub d}{sup 0} {bar B}{sub d}{sup 0} mixing parameter using opposite side lepton and D* meson in p{bar p} collisions at {radical}s = 1.8 TeV

This thesis presents the results from the investigation of time dependent B{sub d}{sup 0} {bar B}{sub d}{sup 0} mixing in B {yields} lepton X, B{sub d}{sup 0} {yields} D*{sup -} {yields} {bar D}{sup 0} {pi}{sup -}, {bar D}{sup 0} {yields} K{sup +} {pi}{sup -} channel in p{bar p} collisions at {radical}s = 1.8 TeV using 110 pb{sup -1} data collected with the CDF detector at the Fermilab Tevatron Collider. The {bar D}{sup 0} vertex is reconstructed. The B{sub d}{sup 0} decay length is estimated using the distance from the primary vertex to the measured position of the D{sup 0} vertex. The B{sup 0} momentum is estimated using the D{sup 0} momentum and a kinematic correction factor from Monte Carlo. With the dilution floating, {Delta}M{sub d} = 0.55 {+-}{sub 0.16}{sup 0.15} (stat) {+-} 0.06 (syst)ps{sup -1} is measured.
Date: January 13, 1998
Creator: Vandenbrink, S.C.
System: The UNT Digital Library
Mechanical and tribological properties of ion beam-processed surfaces (open access)

Mechanical and tribological properties of ion beam-processed surfaces

The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low …
Date: January 1, 1998
Creator: Kodali, P.
System: The UNT Digital Library
On the geometry of inhomogeneous quantum groups (open access)

On the geometry of inhomogeneous quantum groups

The author gives a pedagogical introduction to the differential calculus on quantum groups by stressing at all stages the connection with the classical case. He further analyzes the relation between differential calculus and quantum Lie algebra of left (right) invariant vectorfields. Equivalent definitions of bicovariant differential calculus are studied and their geometrical interpretation is explained. From these data he constructs and analyzes the space of vectorfields, and naturally introduces a contraction operator and a Lie derivative. Their properties are discussed.
Date: January 1, 1998
Creator: Aschieri, P.
System: The UNT Digital Library
Radiant cooling in US office buildings: Towards eliminating the perception of climate-imposed barriers (open access)

Radiant cooling in US office buildings: Towards eliminating the perception of climate-imposed barriers

Much attention is being given to improving the efficiency of air-conditioning systems through the promotion of more efficient cooling technologies. One such alternative, radiant cooling, is the subject of this thesis. Performance information from Western European buildings equipped with radiant cooling systems indicates that these systems not only reduce the building energy consumption but also provide additional economic and comfort-related benefits. Their potential in other markets such as the US has been largely overlooked due to lack of practical demonstration, and to the absence of simulation tools capable of predicting system performance in different climates. This thesis describes the development of RADCOOL, a simulation tool that models thermal and moisture-related effects in spaces equipped with radiant cooling systems. The thesis then conducts the first in-depth investigation of the climate-related aspects of the performance of radiant cooling systems in office buildings. The results of the investigation show that a building equipped with a radiant cooling system can be operated in any US climate with small risk of condensation. For the office space examined in the thesis, employing a radiant cooling system instead of a traditional all-air system can save on average 30% of the energy consumption and 27% of the peak …
Date: January 1998
Creator: Stetiu, C.
System: The UNT Digital Library