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581,512 Matching Results

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Best Match Title Creator Date Created (Newest) Date Created (Oldest) Date Added (Newest) Date Added (Oldest)
Zavalla Quadrangle

Zavalla Quadrangle

Topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:24000
Date: 2004
Creator: United States. Forest Service.
Object Type: Map
System: The Portal to Texas History
Zavalla Quadrangle

Zavalla Quadrangle

Topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:62500
Date: 1931
Creator: Geological Survey (U.S.)
Object Type: Map
System: The Portal to Texas History
ZB/WZ Band Offsets and Carrier Localization in CdTe Solar Cells (open access)

ZB/WZ Band Offsets and Carrier Localization in CdTe Solar Cells

Using the first principles band-structure method, we studied systematically the stability and electronic structure of CdX (X=S, Se, and Te) semiconductors with the zinc-blende (ZB) and wurtzite (WZ) crystal structures.
Date: January 1, 2000
Creator: Wei, S.-H. & Zhang, S. B.
Object Type: Article
System: The UNT Digital Library
The ZCAL Conceptual Design Review (open access)

The ZCAL Conceptual Design Review

None
Date: October 2, 1998
Creator: MacKay, W.; Drees, A. & White, S.
Object Type: Report
System: The UNT Digital Library
ZDC Effective Cross Section for Uranium-Uranium Collisions in Run 12 (open access)

ZDC Effective Cross Section for Uranium-Uranium Collisions in Run 12

N/A
Date: December 9, 2013
Creator: A., Drees
Object Type: Report
System: The UNT Digital Library
Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna (open access)

Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna

Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5percent of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N)<--> LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions.
Date: January 31, 2008
Creator: Avenson, Thomas H.; Ahn, Tae Kyu; Zigmantas, Donatas; Niyogi, Krishna K.; Li, Zhirong; Ballottari, Matteo et al.
Object Type: Article
System: The UNT Digital Library
Zebra mussels attack lakes. (open access)

Zebra mussels attack lakes.

This pamphlet is about how to restrict the spread of the mussels spread and steps to curb it.
Date: September 2015
Creator: Texas. Parks and Wildlife Department.
Object Type: Pamphlet
System: The Portal to Texas History
ZeCalc Algorithm Details (open access)

ZeCalc Algorithm Details

None
Date: August 22, 2012
Creator: Bond, K. C.; Smith, J. A.; Treuer, J. N.; Azevedo, S. G.; Kallman, J. S. & Martz, H. E.
Object Type: Report
System: The UNT Digital Library
Zeeman atomic absorption spectrometry (open access)

Zeeman atomic absorption spectrometry

The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)
Date: August 1, 1978
Creator: Hadeishi, T. & McLaughlin, R.
Object Type: Report
System: The UNT Digital Library
Zeeman interferometry (open access)

Zeeman interferometry

The use of a two-frequency, Zeeman effect laser permits simple, stable, rapid, and highly accurate interferometry. There are a number of interesting applications. Three if them are discussed here.
Date: January 1, 1989
Creator: Johnston, Roger G.
Object Type: Article
System: The UNT Digital Library
Zeeman laser interferometry for detection and chemical analysis (open access)

Zeeman laser interferometry for detection and chemical analysis

Zeeman interferometry has a number of applications for ultrasensitive detection and chemical analysis, including refractive index detection, micro-thermometry, thermooptic spectroscopy, and light scattering.
Date: December 1, 1993
Creator: Johnston, R. G.
Object Type: Article
System: The UNT Digital Library
Zeeman Laser Scattering (ZLS): a new light scattering technique (open access)

Zeeman Laser Scattering (ZLS): a new light scattering technique

A new light scattering technique, called Zeeman Laser Scattering (ZLS), which uses a two-frequency Zeeman effect laser, is described. The Zeeman effect laser produces two coherent, colinear laser beams having orthogonal polarizations. The laser output is passed unfocused through a scattering cell containing the sample of interest, and the light scattered at each scattering angle is detected with a photomultiplier tube mounted on an arm that rotates under computer control about the scattering cell. The phase and amplitude of the beats produced by the interference of the two colinear laser beams are measured. Three different scattering mechanisms to which ZLS is sensitive are described, and the quantitative theory of ZLS is derived from the scattering amplitude matrix formalism. Samples of ZLS data are given. (LEW)
Date: January 1, 1986
Creator: Johnston, Roger G.; Singham, Shermila B. & Salzman, Gary C.
Object Type: Article
System: The UNT Digital Library
Zeeman spectrum of scandium (open access)

Zeeman spectrum of scandium

The spectra of Sc I, Sc II, Sc III, and Sc IV are analyzed through the use of the Zeeman effect. A sliding spark of the author's design is used in conjunction with a 27 kilogauss electromagnet. The spectra have (reciprocal) dispersions of 0.2 to 0.5 A/mm. 10 Sc I levels, 16 Sc II levels and 5 Sc III levels show Zeeman splitting. No Sc IV Zeeman patterns were observed. 2 Sc I, 4 Sc II, and all of the Sc III level data are new.
Date: September 1, 1980
Creator: Lulu, Bruce Alan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
ZEHENDER TECHNIQUE FOR SURFACE-ROUGHNESS MEASUREMENT. (open access)

ZEHENDER TECHNIQUE FOR SURFACE-ROUGHNESS MEASUREMENT.

None
Date: January 1, 1968
Creator: Utley, L. W.
Object Type: Report
System: The UNT Digital Library
Zein synthesis and processing on zein protein body membranes. [Maize proteins] (open access)

Zein synthesis and processing on zein protein body membranes. [Maize proteins]

The storage protein of maize, zein, is translated from messenger RNA on ribosomes bound to the outer membrane of the zein protein bodies. No other proteins appear to be made on this membrane. Before zein is transported through the protein body membrane it undergoes at least two post-translational modifications, which are discussed.
Date: January 1, 1978
Creator: Burr, F A
Object Type: Article
System: The UNT Digital Library
Zella Quadrangle

Zella Quadrangle

Topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:24,000
Date: 1968
Creator: Geological Survey (U.S.)
Object Type: Map
System: The Portal to Texas History
Zella Quadrangle

Zella Quadrangle

Satellite image topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:24,000
Date: 2010
Creator: Geological Survey (U.S.)
Object Type: Map
System: The Portal to Texas History
Zella Quadrangle

Zella Quadrangle

Topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:24000
Date: 1972
Creator: Geological Survey (U.S.)
Object Type: Map
System: The Portal to Texas History
Zella Quadrangle

Zella Quadrangle

Topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:24000
Date: 1985
Creator: Geological Survey (U.S.)
Object Type: Map
System: The Portal to Texas History
Zella Quadrangle

Zella Quadrangle

Topographic map of a portion of Texas from the United States Geological Survey (USGS) project. The map includes towns, historic or notable sites, bodies of water, and other geologic features. Scale 1:24000
Date: 2013
Creator: Geological Survey (U.S.)
Object Type: Map
System: The Portal to Texas History
[Zeolite catalysis in conversion of cellulosics] (open access)

[Zeolite catalysis in conversion of cellulosics]

To transform biomass into fermentable substrate for yeast, we are using zeolites instead of enzymes to catalyze the two bottleneck reactions in biomass conversion, xylose isomerization and ceuobiose hydrolysis. The experimental results on these reactions carried out over various zeolites and other catalysts are presented herein. The advantages and disadvantages of using these catalysts over enzymes are also discussed. Heterogeneous solid catalysts other than zeolites has been employed for cellobiose-to-glucose hydrolysis. The size and shape selectivity that makes zeoutes unique for some reactions can add diffusional hindrance. We have spent some time screening various known solid acidic catalysts. We report that a class of cationic ion exchange resins in the acidified form (e.g. Amberlite) has worked well as an acidic catalyst in hydrolyzing cellobiose to glucose. Our experimental results, together with those obtained from a homogeneous acid catalyst (e.g. sulfuric acid) for comparison are provided. Having succeeded in finding an alternative solid acid catalyst for hydrolysis, we explored other solid resin or other homogeneous but non-enzyme catalyst to carry out the xylose-to-xylulose isomerization. A fairly extensive search has been made. We explored the use of sodium aluminates in the homogeneous phase isomerization of glucose to fructose and obtained a very …
Date: January 1, 1992
Creator: Tsao, G.T.
Object Type: Report
System: The UNT Digital Library
[Zeolite catalysis in conversion of cellulosics] (open access)

[Zeolite catalysis in conversion of cellulosics]

To transform biomass into fermentable substrate for yeast, we are using zeolites instead of enzymes to catalyze the two bottleneck reactions in biomass conversion, xylose isomerization and ceuobiose hydrolysis. The experimental results on these reactions carried out over various zeolites and other catalysts are presented herein. The advantages and disadvantages of using these catalysts over enzymes are also discussed. Heterogeneous solid catalysts other than zeolites has been employed for cellobiose-to-glucose hydrolysis. The size and shape selectivity that makes zeoutes unique for some reactions can add diffusional hindrance. We have spent some time screening various known solid acidic catalysts. We report that a class of cationic ion exchange resins in the acidified form (e.g. Amberlite) has worked well as an acidic catalyst in hydrolyzing cellobiose to glucose. Our experimental results, together with those obtained from a homogeneous acid catalyst (e.g. sulfuric acid) for comparison are provided. Having succeeded in finding an alternative solid acid catalyst for hydrolysis, we explored other solid resin or other homogeneous but non-enzyme catalyst to carry out the xylose-to-xylulose isomerization. A fairly extensive search has been made. We explored the use of sodium aluminates in the homogeneous phase isomerization of glucose to fructose and obtained a very …
Date: December 31, 1992
Creator: Tsao, G. T.
Object Type: Report
System: The UNT Digital Library
Zeolite catalysis in conversion of cellulosics. Annual report (open access)

Zeolite catalysis in conversion of cellulosics. Annual report

The authors have studied the kinetics of oxylose/xylulose isomerization in significant detail over a variety of zeolites and obtained the pseudo-first order reaction rate constants. The authors have found that HY zeolite is still the best material and zeolites are more selective than homogeneous acid catalysts where decomposition of the sugar compounds is much faster. They have completed, as described in the Year 2 Work Plan, the study of cellobiose hydrolysis with an ion exchange resin. The kinetics of the solid-catalyzed reaction is qualitatively similar to that for catalysis by homogeneous acids. The planned program of NMR studies has revealed the dynamics of sugar molecules within the zeolite cavities. Two chemisorbed and a physisorbed state have been identified in HY zeolite. A new state, accounting for as much as a half of the sugar, has been found in ZSM-5 zeolite.
Date: February 1, 1994
Creator: Tsao, G. T.
Object Type: Report
System: The UNT Digital Library
Zeolite catalysis: technology (open access)

Zeolite catalysis: technology

Zeolites have been used as catalysts in industry since the early nineteen sixties. The great majority of commercial applications employ one of three zeolite types: zeolite Y; Mordenite; ZSM-5. By far the largest use of zeolites is in catalytic cracking, and to a lesser extent in hydrocracking. This paper reviews the rapid development of zeolite catalysis and its application in industries such as: the production of gasoline by catalytic cracking of petroleum; isomerization of C/sub 5/ and C/sub 6/ paraffin hydrocarbons; alkylation of aromatics with olefins; xylene isomerization; and conversion of methanol to gasoline.
Date: July 1, 1980
Creator: Heinemann, H.
Object Type: Article
System: The UNT Digital Library