Degree Department

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AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION (open access)

AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION

A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of tailings ash content. Then, based on an on-line estimate of incremental ash, the pulp level is adjusted using a model-based control algorithm to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the eleventh quarter of this project, Task 7 (Operation and Testing) was nearly completed through the efforts of J.A. Herbst and Associates, Virginia Tech, and Pittston Coal Company. As a result of this work, a model-based control system has now been installed which can predict incremental ash based on tailings ash content and general plant data, and adjust pulp level accordingly to maintain a target incremental ash. The system has gone through a shake-down period, training has been carried out for plant operators, and the bulk of the control logic testing has been completed with the results of these tests awaiting analysis under Task 8 (System Evaluation). The flotation model has been shown to predict incremental ash quite successfully, implying that this approach …
Date: January 11, 1999
Creator: Luttrell, G. H. & Adel, G. T.
Object Type: Report
System: The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 99, No. 258, Ed. 1 Monday, January 11, 1999 (open access)

Altus Times (Altus, Okla.), Vol. 99, No. 258, Ed. 1 Monday, January 11, 1999

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: January 11, 1999
Creator: Cole, Carol
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Alvin Sun (Alvin, Tex.), Vol. 108, No. 46, Ed. 1 Monday, January 11, 1999 (open access)

The Alvin Sun (Alvin, Tex.), Vol. 108, No. 46, Ed. 1 Monday, January 11, 1999

Weekly newspaper from Alvin, Texas that includes local, state, and national news along with advertising.
Date: January 11, 1999
Creator: Schwind, Jim & Looby, Edward
Object Type: Newspaper
System: The Portal to Texas History
Application of the Solubility Parameter Concept to the Design of Chemiresistor Arrays (open access)

Application of the Solubility Parameter Concept to the Design of Chemiresistor Arrays

Arrays of unheated chemically sensitive resistors (chemiresistors) can serve as extremely small, low-power-consumption sensors with simple read-out electronics. We report here results on carbon-loaded polymer composites, as well as polymeric ionic conductors, as chemiresistor sensors. We use the volubility parameter concept to understand and categorize the chemiresistor responses and, in particular, we compare chemiresistors fabricated from polyisobutylene (PIB) to results from PIB-coated acoustic wave sensors. One goal is to examine the possibility that a small number of diverse chemiresistors can sense all possible solvents-the "Universal Solvent Sensor Array". keywords: chemiresistor, volubility parameter, chemical sensor
Date: January 11, 1999
Creator: Eastman, M. P.; Hughes, R. C.; Jenkins, M. W.; Patel, S. V.; Ricco, A. J. & Yelton, G.
Object Type: Article
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 77, No. 62, Ed. 1 Monday, January 11, 1999 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 77, No. 62, Ed. 1 Monday, January 11, 1999

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: January 11, 1999
Creator: Dobbs, Gary
Object Type: Newspaper
System: The Portal to Texas History
A Coupled Modeling System to Simulate Water Resources in the Rio Grande Basin (open access)

A Coupled Modeling System to Simulate Water Resources in the Rio Grande Basin

Limited availability of fresh water in arid and semi-arid regions of the world requires prudent management strategies from accurate, science-based assessments. These assessments demand a thorough understanding of the hydrologic cycle over long time periods within the individual water-sheds that comprise large river basins. Measurement and simulation of the hydrologic cycle is a tremendous challenge, involving a coupling between global to regional-scale atmospheric precipitation processes with regional to local-scale land surface and subsurface water transport. Los Alamos National Laboratory is developing a detailed modeling system of the hydrologic cycle and applying this tool at high resolution to assess the water balance within the upper Rio Grande river basin. The Rio Grande is a prime example of a river system in a semiarid environment, with a high demand from agricultural, industrial, recreational, and municipal interests for its water supply. Within this river basin, groundwater supplies often augment surface water. With increasing growth projected throughout the river basin, however, these multiple water users have the potential to significantly deplete groundwater resources, thereby increasing the dependence on surface water resources.
Date: January 11, 1999
Creator: Bossert, J. E.; Breshears, D. D.; Campbell, K.; Costigan, K. R.; Greene, R. K.; Keating, E. H. et al.
Object Type: Article
System: The UNT Digital Library
Cycling Endurance of SONOS Non-Volatile Memory Stacks Prepared with Nitrided SiO(2)/Si(100) Intefaces (open access)

Cycling Endurance of SONOS Non-Volatile Memory Stacks Prepared with Nitrided SiO(2)/Si(100) Intefaces

The effects of nitrided SiO{sub 2}/Si(100) interfaces upon cycling endurance in silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory transistors are investigated. Analysis of MOSFET sub-threshold characteristics indicate cycling degradation to be a manifestation of interface state (D{sub it}) generation at the tunnel oxide/silicon interface. After 10{sup 6} write/erase cycles, SONOS film stacks prepared with nitrided tunnel oxides exhibit enhanced cycling endurance with {Delta}D{sub it}=3x10{sup 12} V{sup -1}cm{sup -2}, compared to {Delta}D{sub it}=2x10{sup 13} V{sup -l}cm{sup -2} for non-nitrided tunnel oxides. Additionally, if the capping oxide is formed by steam oxidation, rather than by deposition, SONOS stacks prepared with non-nitrided tunnel oxides exhibit endurance characteristics similar to stacks with nitrided tunnel oxides. From this observation it is concluded that latent nitridation of the tunnel oxidehilicon interface occurs during steam oxide cap formation.
Date: January 11, 1999
Creator: Habermehl, S.; Nasby, R.D. & Rightley, M.J.
Object Type: Article
System: The UNT Digital Library
Davis-Bacon Act: Labor Now Verifies Wage Data, but Verification Process Needs Improvement (open access)

Davis-Bacon Act: Labor Now Verifies Wage Data, but Verification Process Needs Improvement

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the: (1) Department of Labor's response to the House Appropriations Committee's directive that it verify a random sample of employers' wage data submissions and select a sample of submissions for on-site data verification; and (2) likely effect of these efforts on the accuracy and timeliness of Davis-Bacon Act wage determinations."
Date: January 11, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Deflection of large near-earth objects (open access)

Deflection of large near-earth objects

The Earth is periodically hit by near Earth objects (NEOs) ranging in size from dust to mountains. The small ones are a useful source of information, but those larger than about 1 km can cause global damage. The requirements for the deflection of NEOs with significant material strength are known reasonably well; however, the strength of large NEOs is not known, so those requirements may not apply. Meteor impacts on the Earth`s atmosphere give some information on strength as a function of object size and composition. This information is used here to show that large, weak objects could also be deflected efficiently, if addressed properly.
Date: January 11, 1999
Creator: Canavan, G. H.
Object Type: Article
System: The UNT Digital Library
[Email Exchange on Case Study Schools] (open access)

[Email Exchange on Case Study Schools]

A detailed email conversation capturing strategic discussions on the case study schools.
Date: January 11, 1999, 7:47 a.m.
Creator: unknown
Object Type: Letter
System: The UNT Digital Library
[Email Exchange on Mitchell Case Study Testing] (open access)

[Email Exchange on Mitchell Case Study Testing]

A comprehensive email exchange documenting strategic collaboration on the case study testing at Mitchell.
Date: January 11, 1999, 1:45 p.m.
Creator: unknown
Object Type: Letter
System: The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Monday, January 11, 1999 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Monday, January 11, 1999

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: January 11, 1999
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History
[Funeral Program for James C. Lindsay, January 11, 1999] (open access)

[Funeral Program for James C. Lindsay, January 11, 1999]

Funeral program for James C. Lindsay, born January 18, 1942 and died January 5, 1999. The funeral was held Monday, January 11, 1999 at Hardy's Mortuary Chapel, officiated by Rev. Hector Grant. Funeral arrangements were made through Hardy's Mortuary and he was buried in Fort Sam Houston National Cemetery near San Antonio, Texas.
Date: January 11, 1999
Creator: unknown
Object Type: Pamphlet
System: The Portal to Texas History
House Committee Markup: Amendment Procedure (open access)

House Committee Markup: Amendment Procedure

This report briefly discusses committee markups in the House of Representatives. The essential purpose of a committee markup is to determine whether a measure pending before a committee should be altered, or amended, in any substantive way. Of course, committees do not actually amend measures; instead a committee votes on which amendments it wishes to recommend to the House.
Date: January 11, 1999
Creator: Schneider, Judy
Object Type: Report
System: The UNT Digital Library
House Committee Markup: Preparation (open access)

House Committee Markup: Preparation

Markups provide Members on a committee an opportunity to change parts of a bill prior to its consideration by the full House. A number of administrative, procedural, and substantive steps must be undertaken in preparation for a markup, and other steps could or should be undertaken. Generally, the markup should be strategically planned to minimize controversy, provide Members with political dividends, and position the committee for future action. This report is intended as a guide for various tasks that could be accomplished by committee staff in order to prepare a smooth committee markup.
Date: January 11, 1999
Creator: Schneider, Judy
Object Type: Report
System: The UNT Digital Library
House Committee Markup: Reporting (open access)

House Committee Markup: Reporting

At the end of the amendment process, the chair normally entertains a motion to report a measure favorably to the House. This report addresses the procedural options committees have regarding the form of reporting, such as what happens to amendments adopted in markup, as well as other considerations at the time of reporting.
Date: January 11, 1999
Creator: Schneider, Judy
Object Type: Report
System: The UNT Digital Library
Juvenile Courts: Reforms Aim to Better Serve Maltreated Children (open access)

Juvenile Courts: Reforms Aim to Better Serve Maltreated Children

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed states' and local agencies' efforts to improve the timeliness of judicial decisions concerning the permanent placement of foster children, focusing on: (1) the key problems in the juvenile dependency court system; and (2) state and local responses to these problems."
Date: January 11, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL (open access)

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.
Date: January 11, 1999
Creator: Augenstein, Don
Object Type: Report
System: The UNT Digital Library
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 81, Ed. 1 Monday, January 11, 1999 (open access)

The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 81, Ed. 1 Monday, January 11, 1999

Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date: January 11, 1999
Creator: Allam, Heather
Object Type: Newspaper
System: The Gateway to Oklahoma History
Optical Detection of Aqueous Phase Analytes via Host-Guest Interactions on a Lipid Membrane Surface (open access)

Optical Detection of Aqueous Phase Analytes via Host-Guest Interactions on a Lipid Membrane Surface

The organization and assembly of molecules in cellular membranes is orchestrated through the recognition and binding of specific chemical signals. A simplified version of the cellular membrane system has been developed using a synthetically prepared membrane receptor incorporated into a biologically derived lipid bilayer. Through an interplay of electrostatic and van der Wards interactions, aggregation or dispersion of molecular components could be executed on command using a specific chemical signal. A pyrene fluorophore was used as an optical probe to monitor the aggregational state of the membrane receptors in the bilayer matrix. The pyrene excimer emission to monomer emission (E/M) intensity ratio gave a relative assessment of the local concentration of receptors in the membrane. Bilayers were prepared with receptors selective for the divalent metal ions of copper, mercury, and lead. Addition of the metal ions produced a rapid dispersion of aggregated receptor components at nano- to micro-molar concentrations. The process was reversible by sequestering the metal ions with EDTA. Receptors for proteins and polyhistidine were also prepared and incorporated into phosphatidylcholine lipid bilayers. In this case, the guest molecules bound to the membrane through multiple points of interaction causing aggregation of initially dispersed receptor molecules. The rapid, selective, and …
Date: January 11, 1999
Creator: Sasaki, Darryl Y. & Waggoner, Tina A.
Object Type: Article
System: The UNT Digital Library
Perry Daily Journal (Perry, Okla.), Vol. 106, No. 6, Ed. 1 Monday, January 11, 1999 (open access)

Perry Daily Journal (Perry, Okla.), Vol. 106, No. 6, Ed. 1 Monday, January 11, 1999

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: January 11, 1999
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History

[Photograph 2012.201.B0139.0115]

Photograph used for a newspaper owned by the Oklahoma Publishing Company. Caption: "Vicki Coldiron leads Scored Again from his stall at Maui Farms."
Date: January 11, 1999
Creator: McDaniel, David
Object Type: Photograph
System: The Gateway to Oklahoma History
Physical Basis for Optical Performance of the NIF Amplifiers (open access)

Physical Basis for Optical Performance of the NIF Amplifiers

None
Date: January 11, 1999
Creator: Alger, T.; Erlandson, A.; Fulkerson, S.; Horvath, J.; Jancaitis, K.; Marshall, C. et al.
Object Type: Report
System: The UNT Digital Library
Point Defects in Binary Laves-Phase Alloys (open access)

Point Defects in Binary Laves-Phase Alloys

Point defects in the binary C15 NbCrQ and NbCoz, and C 14 NbFe2 systems on both sides of stoichiometry were studied by both bulk density and X-ray Iattiee parameter measurements. It was found that the vacancy concentrations in these systems after quenching from 1000"C are essentially zero. The constitutional defects on both sides of stoichiometry for these systems were found to be of the anti-site type in comparison with the model predictions. Thermal vacancies exhibiting a maximum at the stoichiometric composition were obtained in NbCr2 Laves phase alloys after quenching from 1400"C. However, there are essentially no thermal vacancies in NbFe2 alloys after quenching from 1300oC. Anti-site hardening was found on both sides of stoichiometry for all the tie Laves phase systems studied, while the thermal vacancies in NbCr2 alloys quenched from 1400'C were found to soften the Laves phase. The anti-site hardening of the Laves phases is similar to that of the B2 compounds and the thermal vacancy softening is unique to the Laves phase. Neither the anti-site defects nor the thermal vacancies affect the fracture toughness of the Laves phases significantly.
Date: January 11, 1999
Creator: Liaw, P. K.; Liu, C. T.; Pike, L. M. & Zhu, J. H.
Object Type: Report
System: The UNT Digital Library