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[News Clip: JFK Files]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
January 24, 1992, 6:00 p.m.
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
The Rambler (Fort Worth, Tex.), Vol. 69, No. 4, Ed. 1 Thursday, September 24, 1992
Weekly student newspaper from Texas Wesleyan University in Fort Worth, Texas that includes campus and local news along with advertising.
Date:
September 24, 1992
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Control of pyrite surface chemistry in physical coal cleaning. Second quarterly progress report, December 1, 1989--February 28, 1990
To better understand the surface chemical properties of coal and mineral pyrite, studies on the effect of flotation surfactants (frother and kerosene) on the degree of hydrophobicity have been conducted. The presence of either frother or kerosene enhanced the flotability of coal and mineral pyrite with a corresponding decrease in induction time over the pH range examined. Scanning electron microscopy (SEM) results indicate a correlation exists between the sample surface morphology and crystal structure and the observed hydrophobicity. As a result of the data obtained from the surface characterization studies, controlled surface oxidation was investigated as a possible pyrite rejection scheme in microbubble column flotation.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H.; Zachwieja, J. & Lagno, M.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning. Seventh quarterly progress report, March 1, 1991--May 31, 1991
The removal of pyrite from coal by flotation or any other surface chemistry based separation process is often hampered by the apparent hydrophobicity of the mineral. Results obtained in this project suggest that corrosion processes are responsible for the apparent hydrophobicity of pyrite in aqueous environments. Characterization of the corrosion products of pyrite in acidic and alkaline solution has been performed using electrochemical (cyclic voltammetry and single-potential-step chronoamperometry) and spectroscopic techniques (X-ray photoelectron spectroscopy -- XPS). The nature of the surface products have been correlated with hydrophobicity determined from in-situ contact angle measurements. The results show that pyrite hydrophobicity is influenced by either the oxidation or reduction conditions of the system.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H. & Zachwieja, J. B.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning
The removal of pyrite from coal by flotation or any other surface chemistry based separation process is often hampered by the apparent hydrophobicity of the mineral. Results obtained in this project suggest that corrosion processes are responsible for the apparent hydrophobicity of pyrite in aqueous environments. Characterization of the corrosion products of pyrite in acidic and alkaline solution has been performed using electrochemical (cyclic voltammetry and single-potential-step chronoamperometry) and spectroscopic techniques (X-ray photoelectron spectroscopy -- XPS). The nature of the surface products have been correlated with hydrophobicity determined from in-situ contact angle measurements. The results show that pyrite hydrophobicity is influenced by either the oxidation or reduction conditions of the system.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H. & Zachwieja, J. B.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning
The successful separation of pyrite from coal by flotation is dependent to a large extent upon the selectivity of the process, and the use of a pyrite depressant is one of the most important and cost-effective techniques for achieving this. This report evaluates the effects of three factors on the floatability of pyrite. These are (1) the superficial oxidation of pyrite, (2) the contamination of pyrite surfaces by carbonaceous matter, and (3) pulp redox potentials. XPS (x-ray photoelectron spectroscopy) and IR spectrometry have been used to identify surface reaction products. Microflotation, laboratory-scale conventional flotation and microbubble column flotation were used to quantify the effects of these factors. It was found that low (reducing) pulp potentials are effective depressants of pyrite (more so for fresh, unoxidized samples than for oxidized samples), whilst at the same time do not materially affect coal flotation.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H. & Ou, Z. S.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning
To better understand the surface chemical properties of coal and mineral pyrite, studies on the effect of flotation surfactants (frother and kerosene) on the degree of hydrophobicity have been conducted. The presence of either frother or kerosene enhanced the flotability of coal and mineral pyrite with a corresponding decrease in induction time over the pH range examined. Scanning electron microscopy (SEM) results indicate a correlation exists between the sample surface morphology and crystal structure and the observed hydrophobicity. As a result of the data obtained from the surface characterization studies, controlled surface oxidation was investigated as a possible pyrite rejection scheme in microbubble column flotation.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H.; Zachwieja, J. & Lagno, M.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning
One of the most difficult separations in minerals processing involves the differential flotation of pyrite and coal. Under practical flotation conditions, they are both hydrophobic and no cost-effective method has been developed to efficiently reject the pyrite. The problem arises from inherent floatability of coal and pyrite. Coal is naturally hydrophobic and remains so under practical flotation. Although pyrite is believed to be naturally hydrophilic under practical flotation conditions it undergoes a relatively rapid incipient oxidation reaction that causes self-induced'' flotation. The oxidation product responsible for self-induced'' flotation is believed to be a metal polysulfide, excess sulfur in the lattice, or in some cases elemental sulfur. It is believed that if incipient oxidation of pyrite could be prevented, good pyrite rejection could be obtained. In order to gain a better understanding of how pyrite oxidizes, a new method of preparing fresh, unoxidized pyrite surfaces and a new method of studying pyrite oxidation have been developed this reporting period.
Date:
June 24, 1992
Creator:
Yoon, R. H. & Richardson, P. R.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning. Tenth quarterly progress report, December 1, 1991--February 29, 1992
One of the most difficult separations in minerals processing involves the differential flotation of pyrite and coal. Under practical flotation conditions, they are both hydrophobic and no cost-effective method has been developed to efficiently reject the pyrite. The problem arises from inherent floatability of coal and pyrite. Coal is naturally hydrophobic and remains so under practical flotation. Although pyrite is believed to be naturally hydrophilic under practical flotation conditions it undergoes a relatively rapid incipient oxidation reaction that causes ``self-induced`` flotation. The oxidation product responsible for ``self-induced`` flotation is believed to be a metal polysulfide, excess sulfur in the lattice, or in some cases elemental sulfur. It is believed that if incipient oxidation of pyrite could be prevented, good pyrite rejection could be obtained. In order to gain a better understanding of how pyrite oxidizes, a new method of preparing fresh, unoxidized pyrite surfaces and a new method of studying pyrite oxidation have been developed this reporting period.
Date:
June 24, 1992
Creator:
Yoon, R. H. & Richardson, P. R.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning. Fifth quarterly progress report, September 1, 1990--November 30, 1990
The successful separation of pyrite from coal by flotation is dependent to a large extent upon the selectivity of the process, and the use of a pyrite depressant is one of the most important and cost-effective techniques for achieving this. This report evaluates the effects of three factors on the floatability of pyrite. These are (1) the superficial oxidation of pyrite, (2) the contamination of pyrite surfaces by carbonaceous matter, and (3) pulp redox potentials. XPS (x-ray photoelectron spectroscopy) and IR spectrometry have been used to identify surface reaction products. Microflotation, laboratory-scale conventional flotation and microbubble column flotation were used to quantify the effects of these factors. It was found that low (reducing) pulp potentials are effective depressants of pyrite (more so for fresh, unoxidized samples than for oxidized samples), whilst at the same time do not materially affect coal flotation.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H. & Ou, Z. S.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning. Third quarterly progress report, March 1, 1990--May 31, 1990
Correlation of the hydrophobicity measurements of coal and mineral pyrite with changes in the surface composition of the samples as determined by x-ray photoelectron spectroscopy (XPS) reveals that similar surface oxidation products are found on both mineral and coal pyrite samples. The surface oxidation layer of these samples is comprised of different amounts of hydrophilic species (iron hydroxy-oxides and/or iron oxides) and hydrophobic species (polysulfide or elemental sulfur). The resulting hydrophobicity of these samples may be attributed to the ratio of hydrophilic (surface oxides) to hydrophobic (sulfur-containing) species in the surface oxidation layer. Also, coal pyrite samples were found to exhibit a greater degree of superficial oxidation and a less hydrophobic character as compared to the mineral pyrite samples.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H.; Zachwieja, J. B. & Lagno, M. L.
Object Type:
Report
System:
The UNT Digital Library
Control of pyrite surface chemistry in physical coal cleaning
Correlation of the hydrophobicity measurements of coal and mineral pyrite with changes in the surface composition of the samples as determined by x-ray photoelectron spectroscopy (XPS) reveals that similar surface oxidation products are found on both mineral and coal pyrite samples. The surface oxidation layer of these samples is comprised of different amounts of hydrophilic species (iron hydroxy-oxides and/or iron oxides) and hydrophobic species (polysulfide or elemental sulfur). The resulting hydrophobicity of these samples may be attributed to the ratio of hydrophilic (surface oxides) to hydrophobic (sulfur-containing) species in the surface oxidation layer. Also, coal pyrite samples were found to exhibit a greater degree of superficial oxidation and a less hydrophobic character as compared to the mineral pyrite samples.
Date:
June 24, 1992
Creator:
Luttrell, G. H.; Yoon, R. H.; Zachwieja, J. B. & Lagno, M. L.
Object Type:
Report
System:
The UNT Digital Library
[Clipping: Gay-officer issue moves back to court after vote]
Newspaper pages from the Dallas Morning News for January 24, 1992. "Gay-officer issue moves back to court after vote" provides an update on the Dallas Police Department's hiring practices of gay officers.
Date:
January 24, 1992
Creator:
Camia, Catalina
Object Type:
Clipping
System:
The UNT Digital Library
[News Clip: Alamo - treasure]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, covering a news story. This story aired at 10pm.
Date:
October 24, 1992, 10:00 p.m.
Creator:
KXAS-TV (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
Texas Register, Volume 17, Number 55, Pages 5159-5247, July 24, 1992
A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date:
July 24, 1992
Creator:
Texas. Secretary of State.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
The Hopkins County Echo (Sulphur Springs, Tex.), Vol. 117, No. 17, Ed. 1 Friday, April 24, 1992
Weekly newspaper from Sulphur Springs, Texas that includes local, state, and national news along with advertising.
Date:
April 24, 1992
Creator:
Keys, Clarke & Lamb, Bill
Object Type:
Newspaper
System:
The Portal to Texas History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 78, No. 269, Ed. 1 Friday, July 24, 1992
Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date:
July 24, 1992
Creator:
Lake, Charles S.
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Big Lake Wildcat (Big Lake, Tex.), Vol. SIXTY SEVENTH YEAR, No. 39, Ed. 1 Thursday, September 24, 1992
Weekly newspaper from Big Lake, Texas that includes local, state and national news along with advertising.
Date:
September 24, 1992
Creator:
Werst, David
Object Type:
Newspaper
System:
The Portal to Texas History
Burleson Star (Burleson, Tex.), Vol. 27, No. 37, Ed. 1 Monday, February 24, 1992
Semi-weekly newspaper from Burleson, Texas that includes local, state, and national news along with advertising.
Date:
February 24, 1992
Creator:
Ellertson, Sally
Object Type:
Newspaper
System:
The Portal to Texas History
The Canadian Record (Canadian, Tex.), Vol. 102, No. 52, Ed. 1 Thursday, December 24, 1992
Weekly newspaper from Canadian, Texas that includes local, state and national news along with extensive advertising.
Date:
December 24, 1992
Creator:
Ezzell, Ben & Ezzell, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Texas Register, Volume 17, Number 88, Pages 8199-8247, November 24, 1992
A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date:
November 24, 1992
Creator:
Texas. Secretary of State.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Dallas Voice (Dallas, Tex.), Vol. 8, No. 53, Ed. 1 Friday, April 24, 1992
Weekly newspaper from Dallas, Texas that includes local, state, and national news and advertising of interest to the Lesbian, Gay, Bisexual, and Transgender (LGBT) community.
Date:
April 24, 1992
Creator:
Vercher, Dennis
Object Type:
Newspaper
System:
The UNT Digital Library
The Rice Thresher (Houston, Tex.), Vol. 79, No. 17, Ed. 1 Friday, January 24, 1992
A weekly student newspaper from the Rice University in Houston, Texas that includes campus news and commentaries along with advertising.
Date:
January 24, 1992
Creator:
Zitterkopf, Ann & Howe, Harlan
Object Type:
Newspaper
System:
The Portal to Texas History
The Albany News (Albany, Tex.), Vol. 117, No. 16, Ed. 1 Thursday, September 24, 1992
Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date:
September 24, 1992
Creator:
Lucas, Donnie A.
Object Type:
Newspaper
System:
The Portal to Texas History