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2000

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Articles 2371 - 2400 of 2647

Full-Text Articles in Physical Sciences and Mathematics

Polybutadiene Cross-Linked With Various Diols – Effect On Thermal Stability, Fawn Marie Uhl, Michael A. Mckinney, Charles A. Wilkie Jan 2000

Polybutadiene Cross-Linked With Various Diols – Effect On Thermal Stability, Fawn Marie Uhl, Michael A. Mckinney, Charles A. Wilkie

Chemistry Faculty Research and Publications

The relationship between cross-linking and thermal stability as related to polybutadiene is the focus of current research. Cross-linked polybutadienes have been prepared using various diols as the cross-linking agent. Cross-linked polymers have been characterized by gel content, swelling ratios, infrared spectroscopy, and thermal analysis. These polymers are not highly cross-linked, as seen by gel content and swelling ratios, and cross-linking does not have a large effect on the onset temperature of the degradation. Nonetheless, extensive formation of a non-volatile residue occurs.

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Cross-Linking Of Polystyrene By Friedel-Crafts Chemistry: Multi-Functional Additives, Hongyang Yao, Jin Zhu, Michael A. Mckinney, Charles A. Wilkie Jan 2000

Cross-Linking Of Polystyrene By Friedel-Crafts Chemistry: Multi-Functional Additives, Hongyang Yao, Jin Zhu, Michael A. Mckinney, Charles A. Wilkie

Chemistry Faculty Research and Publications

Various multifunctional aromatic compounds were synthesized and tested to ascertain if they were able to cross-link polystyrene. Catalysis and inhibition at high temperature were studied to achieve control over the cross-linking temperature, in order to develop suitable formulations which may function as flame retardants.

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Cattle And Amblyomma Variegatum Odors Used In Host Habitat And Host Finding By The Tick Parasitoid, Ixodiphagus Hookeri, Fanuel A. Demas, Ahmed Hassanali, Esther N. Mwangi, Edna C. Kunjeku, Audrey R. Mabveni Jan 2000

Cattle And Amblyomma Variegatum Odors Used In Host Habitat And Host Finding By The Tick Parasitoid, Ixodiphagus Hookeri, Fanuel A. Demas, Ahmed Hassanali, Esther N. Mwangi, Edna C. Kunjeku, Audrey R. Mabveni

All Peer-Reviewed Publications

The response of mated naive Ixodiphagus hookeri females to cattle and Amblyomma variegatum nymphal odors was tested in a Y-tube olfactometer. I. hookeri females were attracted to cattle urine, dung, and odors from tick- free feeding sites of A. variegatum nymphs on cattle, e.g., dewlaps, front heels, and hind heels. Tick-free scrotal odors did not attract the parasitoids. Furthermore, odors from off-host unfed and fed A. variegatum nymphs did not attract the parasitoids, despite an increase in the number of the nymphs to amplify any odor signal. A blend of odors from feeding on-host nymphs and cattle scrota attracted the …

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Book Review: The Birth Of Time: How Astronomers Measured The Age Of The Universe, T. D. Oswalt Jan 2000

Book Review: The Birth Of Time: How Astronomers Measured The Age Of The Universe, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The Birth of Time : How Astronomers Measured the Age of the Universe by John Gribbin. Yale, 2000 237p, 0-300-08346-7 $22.50.

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Fact Sheet, Yale University Office Of Institutional Research Jan 2000

Fact Sheet, Yale University Office Of Institutional Research

Fact Sheets

No abstract provided.

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Can An Optical Plankton Counter Produce Reasonable Estimates Of Zooplankton Abundance And Biovolume In Water With High Detritus?, X. Zhang, M. Roman, A. Sanford, H. Adolf, C. Lascara, R. Burgett Jan 2000

Can An Optical Plankton Counter Produce Reasonable Estimates Of Zooplankton Abundance And Biovolume In Water With High Detritus?, X. Zhang, M. Roman, A. Sanford, H. Adolf, C. Lascara, R. Burgett

CCPO Publications

The Optical Plankton Counter (OPC) has been used in oceanic and fresh waters to estimate zooplankton abundance and biovolume. However, it is not clear whether the OPC can produce accurate estimates of zooplankton abundance and biovolume in waters with high detritus. In order to test the capability of the OPC to estimate zooplankton abundance and biovolume in Chesapeake Bay, two sets of laboratory experiments were conducted using water with high detritus concentrations collected from the upper Choptank estuary of Chesapeake Bay and laboratory cultured Artemia. Our results suggest that the OPC is able to produce accurate estimates of zooplankton biovolume …

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Fortnightly Variability In The Transverse Dynamics Of A Coastal Plain Estuary, Arnoldo Valle-Levinson, Kuo-Chuin Wong, Kamazima M. M. Lwiza Jan 2000

Fortnightly Variability In The Transverse Dynamics Of A Coastal Plain Estuary, Arnoldo Valle-Levinson, Kuo-Chuin Wong, Kamazima M. M. Lwiza

CCPO Publications

Current velocity and water density profiles were obtained along two crossestuary transects with the purpose of determining the fortnightly variability of the transverse dynamics in a partially stratified coastal plain estuary. The profiles were measured with a towed acoustic Doppler current profiler and a conductivity-temperaturedepth recorder in the James River estuary, Virginia. The cross-estuary transects were sampled during the spring tides of October 26-27, 1996, and the ensuing neap tides of November 2-3, 1996. The transects were-4 km long, featured a bathymetry that consisted of a channel flanked by shoals, and were sampled repeatedly during two semidiurnal tidal cycles (25 …

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On The Sources Of Weddell Gyre Antarctic Bottom Water, Michael P. Meredith, Ricardo A. Locarnini, Kim A. Van Scoy, Andrew J. Watson, Karen J. Heywood, Brian A. King Jan 2000

On The Sources Of Weddell Gyre Antarctic Bottom Water, Michael P. Meredith, Ricardo A. Locarnini, Kim A. Van Scoy, Andrew J. Watson, Karen J. Heywood, Brian A. King

CCPO Publications

In March-April 1995, as part of the World Ocean Circulation Experiment section A23, we completed 49 hydrographic stations across the Weddell Gyre and southern Antarctic Circumpolar Current, from the Antarctic continental shelf (72.5°S, 16.5°W) to South Georgia (55°S, 34.5°W). Chlorofiuorocarbon (CFC11, CFC-12, and CFC-113) data collected at these stations reveal that distinct sources renew the Antarctic Bottom Water (defined as waters with potential temperatures less than 0°C) of the Weddell Gyre. Weddell Sea Bottom Water (defined as waters with potential temperatures less than- 0.7°C) formed in the western Weddell Sea has CFC concentrations about 5 to 6 times higher in …

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Soapbox: The Academic Research Fleet: An Exciting Time For Renewal, Larry Atkinson Jan 2000

Soapbox: The Academic Research Fleet: An Exciting Time For Renewal, Larry Atkinson

CCPO Publications

(First Paragraph) Academic research ships in the United States are the envy of many scientists around the world. A great strength of our system is the diversity of ships and operators: users have a choice, the system can change. A weakness of the system is that very diversity: sometimes it is hard for us to act together. Nevertheless, we now must act together. The vitality of the academic fleet in the coming decades is at stake. The reason is simply because many of our ships, especially in the intermediate size range, will soon reach the end of their useful life.

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Convergence Of Lateral Flow Along A Coastal Plain Estuary, Arnoldo Valle-Levinson, Chunyan Li, Kuo-Chuin Wong, Kamazima M. M. Lwiza Jan 2000

Convergence Of Lateral Flow Along A Coastal Plain Estuary, Arnoldo Valle-Levinson, Chunyan Li, Kuo-Chuin Wong, Kamazima M. M. Lwiza

CCPO Publications

A set of velocity profiles obtained in the James River estuary with an acoustic Doppler current profiler was used in combination with the results of an analytic tidal model to depict the appearance of surface lateral flow convergences (δv/δy) during both flood and ebb stages of the tidal cycle. The bathymetry of the estuary was characterized by a main channel and a secondary channel separated by relatively narrow shoals. Lateral surface flow convergences appeared over the edges of the channels and were produced by the phase lag of the flow in the channel relative to the …

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Measurements Of Salinity In The Coastal Ocean: A Review Of Requirements And Technologies, Catherine Woody, Eddie Shih, Jerry Miller, Thomas Royer, Larry P. Atkinson, Richard S. Moody Jan 2000

Measurements Of Salinity In The Coastal Ocean: A Review Of Requirements And Technologies, Catherine Woody, Eddie Shih, Jerry Miller, Thomas Royer, Larry P. Atkinson, Richard S. Moody

CCPO Publications

Salinity, a measure of the dissolved salts in seawater, is a fundamental property of seawater and basic to understanding biological and physical processes in coastal waters. In the open ocean long term salinity measurements are identified as necessary to understand global climate studies, hydrological cycle, and circulation. In the coastal oceans, information on salinity is critical to understanding biological effects on ecosystem function such as disease, nursery grounds, or harmful algal blooms and on physical processes such as freshwater runoff estuarine mixing, and coastal currents. While the importance of salinity is recognized, little attention has been given to making routine …

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Microhollow Cathode Discharge Excimer Lamps, Karl H. Schoenbach, Ahmed El-Habachi, Mohamed M. Moselhy, Wenhui Shi, Robert H. Stark Jan 2000

Microhollow Cathode Discharge Excimer Lamps, Karl H. Schoenbach, Ahmed El-Habachi, Mohamed M. Moselhy, Wenhui Shi, Robert H. Stark

Bioelectrics Publications

Microhollow cathode discharges are high-pressure, nonequilibrium gas discharges between a hollow cathode and a planar or hollow anode with electrode dimensions in the 100 μm range. The large concentration of high-energy electrons, in combination with the high-gas density favors excimer formation. Excimer emission was observed in xenon and argon, at wavelengths of 128 and 172 nm, respectively, and in argon fluoride and xenon chloride, at 193 and 308 nm. The radiant emittance of the excimer radiation was found to increase monotonically with pressure. However, due to the decrease in source size with pressure, the efficiency (ratio of excimer radiant power …

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University Of Texas At Tyler Catalog, 2000-2002, University Of Texas At Tyler Jan 2000

University Of Texas At Tyler Catalog, 2000-2002, University Of Texas At Tyler

Catalogs

Archives Space instance: https://archivesspace.uttyler.edu/repositories/2/archival_objects/22362

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Disarticulation And Dissolution Of Crab Remains Across A Depth Gradient In The Bahamas: A Taphonomic Study, Rebecca A. Lincoln Jan 2000

Disarticulation And Dissolution Of Crab Remains Across A Depth Gradient In The Bahamas: A Taphonomic Study, Rebecca A. Lincoln

Honors Papers

The fields of Paleontology and Paleoecology would not be complete without taphonomy, the study of the processes affecting organisms between death and fossilization. Taphonomy is important because it allows us to make more complete conjectures about prehistoric organisms and environments, and makes us aware of possible holes and biases in the fossil record due to highly destructive processes or the loss of delicate, non-resistant organisms. Studies on the processes affecting modern organisms have contributed greatly to the understanding of ancient processes; however, most of these studies are nearshore and short-term. What is lacking is information on the effects of these …

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The Wiyn Open Cluster Study: A New Color-Magnitude Diagram For M35 - A Twin Of The Pleiades, Ted Von Hippel, Vera Kozhurina-Platais, Imants Platais, Pierre Demarque, Ata Sarajedini Jan 2000

The Wiyn Open Cluster Study: A New Color-Magnitude Diagram For M35 - A Twin Of The Pleiades, Ted Von Hippel, Vera Kozhurina-Platais, Imants Platais, Pierre Demarque, Ata Sarajedini

Publications

M35 (NGC 2168) is rich, young, and in some regards a bet­ter laboratory for stellar cluster research at 100 million years than the Pleiades. Yet, while M35 has been the subject of intriguing photometric, astrometric, and theoretical studies, to the best of our knowledge no pub­lished CCD-based photometry exists for this cluster. We have obtained relatively wide-field (23' x23') precise UBVRJ CCD photometry for M35 as part of the WIYN Open Cluster Study (WOCS) at the 0.9m telescope at Kitt Peak National Observatory. The photometry extends from the main sequence turn off to beyond V = 19. We find that …

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Verification Of The Causes Of Glaciations And Sea Level Changes Using The Records Of Calcite Speleothems, Y. Shopov, D. Stoykova, L. Tsankov, M. Sanabria, J. Lundberg, L. Georgiev, P. Forti, D. Georgieva Jan 2000

Verification Of The Causes Of Glaciations And Sea Level Changes Using The Records Of Calcite Speleothems, Y. Shopov, D. Stoykova, L. Tsankov, M. Sanabria, J. Lundberg, L. Georgiev, P. Forti, D. Georgieva

International Journal of Speleology

The luminescence of calcite speleothems displays an exponential dependence on soil temperature unless there is a dense cover of forest over the cave to dampen it. This relationship is determined primarily by the strength of solar visible and infrared radiation. It is suggested that, as a consequence, the microzonal variations of luminescence often found in speleothems can be used as a proxy index of Solar Insolation. The luminescence solar insolation proxy record of a speleothem from Jewel Cave, South Dakota, USA, was found to display millenial and centennial cycles in the record. It exhibits a rapid increase in solar insolation …

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Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard Jan 2000

Electroanalysis Using Differential Pulse Methods And Stripping Techniques., Enda Howard

Masters

Application of a differential pulse waveform to a microelectrode or a rotating disk electrode results in a peaked response for amperometric redox reactions. Based on these observations models were proposed and tested for these methods. Simulations of the models were carried out by inputting the relevant equations into Microsoft Excel. The microelectrode study revealed a good correlation between one model and the numerical derivative of the current following a linear sweep potential waveform. Experimentally the derivative can be obtained numerically following a linear sweep. The alternative differential pulse waveform requires more sophisticated equipment and the response can be affected by …

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Studies On The Methylation Of 5-Nitro-Benzimidazoles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus Jan 2000

Studies On The Methylation Of 5-Nitro-Benzimidazoles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus

Turkish Journal of Chemistry

Methylation of 2H, 5-nitro- (1) and 2-ethyl, 5-nitro- (2) benzimidazoles separately with methyl iodide in acetone in the presence of potassium carbonate yielded 2H, 5/6-nitro-(3A and 3B) and 2-ethyl, 5/6-nitro- (4A and 4B) methylbenzimidazoles respectively. Methylation of 1 and 2 in dimethylformamide in place of acetone yielded not only 3A, 3B and 4A, 4B respectively, but in addition 1,3-dimethyl-5-nitro-benzimidazol-2-one (5) was also obtained in each case. The structure of the synthesized compounds was determined with the help of mass and ^1H NMR spectroscopic analysis.

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A System For Analysing Patient History (Az-Phis), Kemalatha Krishnasamy Jan 2000

A System For Analysing Patient History (Az-Phis), Kemalatha Krishnasamy

Student Works (2000-2009)

The improvement of health care service has a great effect on patient satisfaction. In order to improve the health care service, effective processing of patient history and analysis on the respondent is necessary. The results of the statistical analysis performed on patient history eases the decision making of physicians and other related medical staff. Therefore, this dissertation mainly investigates information pertaining to patient history, statistical analysis, and development of a system for analyzing patient history. The study employs the questionnaire survey method to gather data and make analyses using the Spreadsheet; Microsoft® Excel 97. The survey was done in government …

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Thickness Variation Of Self-Processing Acrylamide-Based Photopolymer And Reflection Holography, F. O'Neill, Justin Lawrence, J. Sheridan Jan 2000

Thickness Variation Of Self-Processing Acrylamide-Based Photopolymer And Reflection Holography, F. O'Neill, Justin Lawrence, J. Sheridan

Articles

There are many types of holographic recording material. The acrylamide-based recording material examined here has one significant advantage: it is self-processing. This simplifies the recording process and enables holographic interferometry to be carried out without the need for complex realignment procedures. However, the effect that the polymerization process has on the grating thickness must be examined. This question is fundamental to the material's use in holographic optical elements, as thickness variations affect the replay conditions of the produced elements. This paper presents a study of this thickness variation and reports for the first time the production of reflection holographic gratings …

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Production Of A Signal By Irradiated Cells Which Leads To A Response In Unirradiated Cells Characteristic Of Initiation Of Apoptosis, Fiona Lyng, C. Seymour, C. Mothersill Jan 2000

Production Of A Signal By Irradiated Cells Which Leads To A Response In Unirradiated Cells Characteristic Of Initiation Of Apoptosis, Fiona Lyng, C. Seymour, C. Mothersill

Articles

This study investigated the ability of medium from irradiated cells to induce early events in the apoptotic cascade, such as mobilization of intracellular calcium, loss of mitochondrial membrane potential and increase in reactive oxygen species, in cells which were never exposed to radiation. Medium from irradiated human keratinocytes was harvested and transferred to unirradiated keratinocytes. Endpoints characteristic of the initiation of apoptosis were monitored for a period of 24 h following medium transfer. Clonogenic survival was also measured. Rapid calcium fluxes (within 30 s), loss of mitochondrial membrane potential, increases in reactive oxygen species (from 6 h after medium transfer), …

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Dynamics Of Interfacial Polymers In Composites, Frank D. Blum, Wuu-Yung Lin Jan 2000

Dynamics Of Interfacial Polymers In Composites, Frank D. Blum, Wuu-Yung Lin

Chemistry Faculty Research & Creative Works

Much experimental and theoretical work has been done on the behavior of adsorbed polymers. However, not much work has focused on the dynamics, especially segmental dynamics, of the adsorbed polymers. This is especially true of filled polymer or composite systems as the interfacial layers in these systems are difficult to study with most techniques. NMR is not restricted to use in optically clear samples and its use in the characterization in the surface polymers has been reviewed. In our laboratory, we have found that deuterium NMR could be used to probe the segmental dynamics of adsorbed polymers. The position of …

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Search For Resonances Decaying To E+-Jet In E+P Interactions At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Jan 2000

Search For Resonances Decaying To E+-Jet In E+P Interactions At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The e+-jet invariant mass spectrum produced in the reaction e+p → e+ X has been studied at a center-of-mass energy of 300 GeV. The data were collected using the ZEUS detector operating at the HERA collider, and correspond to an integrated luminosity of 47.7 pb-1. The observed mass spectrum is in good agreement with Standard Model expectations up to an e+-jet mass of 210 GeV. Above this mass, some excess is seen. The angular distribution of these events is typical of high-Q2 neutral current events and does not give convincing evidence for the presence of a narrow scalar or vector …

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Bismuth(Iii) Oxide Perchlorate Promoted Rearrangement Of Epoxides To Aldehydes And Ketones, Ram Mohan, Andrew Anderson, Jesse Blazek, Parie Garg, Brian Payne Jan 2000

Bismuth(Iii) Oxide Perchlorate Promoted Rearrangement Of Epoxides To Aldehydes And Ketones, Ram Mohan, Andrew Anderson, Jesse Blazek, Parie Garg, Brian Payne

Scholarship

Aryl-substituted epoxides and aliphatic epoxides with a tertiary epoxide carbon undergo smooth rearrangement in the presence of 10–50 mol% bismuth(III) oxide perchlorate, BiOClO4•xH2O, to give carbonyl compounds. The rearrangement is regioselective with aryl substituted epoxides and a single carbonyl compound arising from cleavage of benzylic C―O bond is formed. BiOClO4•xH2O is relatively non-toxic, insensitive to air and inexpensive, making this catalyst an attractive alternative to more corrosive and toxic Lewis acids such as BF3•Et2O or InCl3 currently used to effect epoxide rearrangements.

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Isolation Of Curcumin From Tumeric, Ram Mohan, Andrew Anderson, Matthew Mitchell Jan 2000

Isolation Of Curcumin From Tumeric, Ram Mohan, Andrew Anderson, Matthew Mitchell

Scholarship

No abstract provided.

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The Discovery-Oriented Approach To Organic Chemistry. 3. Boron-Trifluoride Catalyzed Rearrangement Of Cis- And Trans-Stilbene Oxides. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram Mohan, Erik Sgariglia, Regina Schopp, Kostas Gavardinas Jan 2000

The Discovery-Oriented Approach To Organic Chemistry. 3. Boron-Trifluoride Catalyzed Rearrangement Of Cis- And Trans-Stilbene Oxides. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram Mohan, Erik Sgariglia, Regina Schopp, Kostas Gavardinas

Scholarship

Epoxides, or oxiranes, are among the most versatile intermediates in organic synthesis. Yet very few examples of laboratory experiments involving reactions of epoxides are to be found in lab texts. We have developed a discovery-oriented laboratory experiment that involves the rearrangement of both cis- and trans-stilbene oxides with boron trifluoride etherate. The identity of the product can be easily determined by 1H NMR spectroscopy and, in case of the trans isomer, by preparation of the semicarbazone derivative as well. In spite of the simplicity of the experiment, the element of discovery ensures that student interest and enthusiasm are retained.

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Analysis Of Remote Sensing Data For Development Of I/M Program Evaluation Protocols, Sajal S. Pokharel, Gary A. Bishop, Donald H. Stedman Jan 2000

Analysis Of Remote Sensing Data For Development Of I/M Program Evaluation Protocols, Sajal S. Pokharel, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

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A Brief Biography Of Professor L.C. Hsu (Lizhi Xu), Tian-Xiao He Jan 2000

A Brief Biography Of Professor L.C. Hsu (Lizhi Xu), Tian-Xiao He

Scholarship

No abstract provided.

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Rsd Versus Im240 Fleet Average Correlations, Sajal S. Pokharel, Donald H. Stedman, Gary A. Bishop Jan 2000

Rsd Versus Im240 Fleet Average Correlations, Sajal S. Pokharel, Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

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Development Of A Quality Control Procedure For Force Platforms, Jacinta Browne, Neil O'Hare Jan 2000

Development Of A Quality Control Procedure For Force Platforms, Jacinta Browne, Neil O'Hare

Articles

A force platform is a technical method of quantitatively assessing balance indirectly. The use of force platforms in physiotherapy departments has become more prominent over the last few years. However, the main drawback in the use of force platforms is the lack of comprehensive calibration procedures, which casts doubt on the results obtained with these systems. Existing calibration tests are limited to testing the spatial accuracy of the force platform. This paper describes a comprehensive quality control test procedure which was developed. It is proposed that the developed quality control test procedure could be used to test all types of …

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