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2000

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Articles 2071 - 2100 of 2647

Full-Text Articles in Physical Sciences and Mathematics

Synthetic Metal Alloys: Preparation Of Polyaniline/Polypyrrole Alloys In Protic Medium, Fati̇h Köleli̇, Meltem Düdükcü, Yasemi̇n Arslan Jan 2000

Synthetic Metal Alloys: Preparation Of Polyaniline/Polypyrrole Alloys In Protic Medium, Fati̇h Köleli̇, Meltem Düdükcü, Yasemi̇n Arslan

Turkish Journal of Chemistry

Pyrrole and aniline solutions were mixed in different ratios and oxidized under anodic conditions on Pt surface in protic medium. The electrocopolymerization and electrochemical properties of these alloys were investigated. Current-potential diagrams of polyaniline (PA), polypyrrole (PP) and the resulting alloys were recorded and their electrochemical characterizations were identified. In-situ resistance measurements of synthesized alloys were carried out with a home-made apparatus. Conductivity of alloys showed changes depending on applied potential as intrinsic polymers. The electrochemical behaviour of homopolymers and alloys was studied at different temperatures.


A Convenient Synthesis Of Some 4-(Alkylamino)-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones, Bahi̇tti̇n Kahveci̇, Aykut İki̇zler Jan 2000

A Convenient Synthesis Of Some 4-(Alkylamino)-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones, Bahi̇tti̇n Kahveci̇, Aykut İki̇zler

Turkish Journal of Chemistry

A series of 3-alkyl-4-(arylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones, {\bfseries 6-10,} was obtained from the reaction of the corresponding 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones, {\bfseries 1,} with the appropriate aldehydes. 3-alkyl-4-(alkylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones of type {\bfseries 11-16} were synthesized from the selective reduction of compounds {\bfseries 5-10} with NaBH$_{4}$ in diglyme or DMSO medium as a general and convenient method.


Ion-Selective Membrane Electrode For The Determination Of A Novel Phenylpiperazine Antidepressant, Nefazodone, Arzum Erdem, Di̇lşat Özkan, Kağan Kerman, Burcu Meri̇ç, Tayfun Dalbasti, Mehmet Özsöz Jan 2000

Ion-Selective Membrane Electrode For The Determination Of A Novel Phenylpiperazine Antidepressant, Nefazodone, Arzum Erdem, Di̇lşat Özkan, Kağan Kerman, Burcu Meri̇ç, Tayfun Dalbasti, Mehmet Özsöz

Turkish Journal of Chemistry

The construction and performance characteristics of ion-selective membrane electrodes for a newly found phenylpiperazine antidepressant, Nefazodone (NFN), based on its ion-pair complexes with phosphotungstate (PT), tetraphenylborate (TPB), tungstosilicate (TS) and reineckate (RN) in a poly(vinyl chloride) (PVC) matrix are described. The best ion-selective electrode for determination of NFN contains NFN-PT as the active material. This electrode exhibits a Nernstian response (62.6 ± 0.4 mV per decade) in the range 1.5 x 10$^{-5}$ to 1.0 x 10^{-2} M NFN.HCl in solutions. The selectivity of this electrode to NFN in the presence of a number of sugar molecules, cations and drugs is …


Investigation Of The Synthesis Of Some Dehydroalanine Derivatives, Si̇bel Süzen, John Michael Williams Jan 2000

Investigation Of The Synthesis Of Some Dehydroalanine Derivatives, Si̇bel Süzen, John Michael Williams

Turkish Journal of Chemistry

Dehydroamino acids represent an important class of compound as they are key intermediates in unusual amino acid and in the design of peptides and are constituents of a variety of naturally occurring antibiotic and phytotoxic peptides. In view of the importance of proteins and peptides containing hydroxyamino acids and the problems associated with their synthesis and dehydration, an investigation was performed on model compounds in order to examine the difficulties of the dehydration reactions. The preparation and properties of the model dehydroalanine derivatives have been studied.


Hplc/Hydride Generation Aas Coupling For The Speciation Of Sb(Iii) And Sb(V) In Wastewaters, Nuray Şatiroğlu, Sema Bektaş, Ömer Genç, Haydar Hazel Jan 2000

Hplc/Hydride Generation Aas Coupling For The Speciation Of Sb(Iii) And Sb(V) In Wastewaters, Nuray Şatiroğlu, Sema Bektaş, Ömer Genç, Haydar Hazel

Turkish Journal of Chemistry

A comparative study was made with two HPLC columns of different lengths (PRP-X 100, 250 mm \( \times \) 4.1 mm id and PRP-X 100, 100 mm \( \times \) 4.1 mm id) coupled to HGAAS for the speciation of inorganic Sb(III) and Sb(V) species. The effects of eluent concentration and pH on the retention times of Sb species in both columns were investigated. The separation of Sb species was realized by using 50 mmol/L citrate solution at pH 4.0 as the eluent. The retention times were 2.0 min and 10.0 min in the 250 mm column, and 1.4 min …


Zinc Determination In Pleural Fluid, Nazan Demi̇r, Yaşar Demi̇r, Ebubeki̇r Bakan, İrfan Küfrevi̇oğlu Jan 2000

Zinc Determination In Pleural Fluid, Nazan Demi̇r, Yaşar Demi̇r, Ebubeki̇r Bakan, İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

In this study, an enzymatic zinc determination method was applied to pleural fluid, the basis of which was the regaining of the activity of apo carbonic anhydrase by the zinc present in the sample. The method was used for pleural fluid zinc determination in order to show the application to body fluids other than serum. For this purpose, pleural fluids were obtained from 20 patients and zinc concentrations were determined. Carbonic anhydrase was purified by affinity chromatography from bovine erythrocytes. The zinc present in its structure was removed by dialysis against dipicolinic acid, resulting in apoenzyme obtained at a ratio …


X-Ray Powder Diffraction And Ir Study Of Calcium Borophosphate Cabpo_5, A. Baykal, G. Gözel, Meral Kizilyalli, M. Toprak, R. Kniep Jan 2000

X-Ray Powder Diffraction And Ir Study Of Calcium Borophosphate Cabpo_5, A. Baykal, G. Gözel, Meral Kizilyalli, M. Toprak, R. Kniep

Turkish Journal of Chemistry

In this study, CaBPO_5 was synthesized by different solid state reactions than reported before and its X-ray powder diffraction and IR data were reported. In one of these solid state reactions BPO_4 was used as a phosphating agent. The examination of the X-ray powder diffraction data showed that this compound crystallized in a hexagonal system and the refined unit cell parameters were a = 6.684, c = 6.616(2) \AA, with Z=3 as reported before. From the observed reflections, the space group was determined as P3_121, and its density was found to be 3.15 g/cc. The X-ray powder diffraction and IR …


All Solid-State Contact Lead(Ii) Ion-Selective Pvc Membrane Electrode Using Dimethylene Bis(4-Methylpiperidinedithiocarbamate) Neutral Ionophore, İbrahi̇m Işildak Jan 2000

All Solid-State Contact Lead(Ii) Ion-Selective Pvc Membrane Electrode Using Dimethylene Bis(4-Methylpiperidinedithiocarbamate) Neutral Ionophore, İbrahi̇m Işildak

Turkish Journal of Chemistry

All solid-state contact PVC membrane electrodes for lead(II) ion were developed by using dimethylene bis(4-methylpiperidinedithiocarbamate) as neutral carrier and nitrophenyloctyl ether or dioctylsebacate as plasticizers. Response properties of the all solid-state contact PVC membrane electrode prepared with nitrophenyloctyl ether were better than those of the membrane electrode prepared with dioctylsebacate. The nitrophenyloctyl ether plasticized the all solid-state contact PVC membrane electrode and exhibited a good linear response of 30 mV/decade for lead(II) ion within the concentration ranges \( 0.1-5\times10^{-6} \) mol dm\( ^{-3} \) lead(II) nitrate, good selectivity over alkali, alkali-earth and transition metal ions including copper(II) ion by a …


High-Performance Liquid Chromatographic Determination Of Oxytetracycline Residue In Cured Meat Products, Hami̇de Z. Şenyuva, Tuncel Özden, Deni̇z Yurtsever Sarica Jan 2000

High-Performance Liquid Chromatographic Determination Of Oxytetracycline Residue In Cured Meat Products, Hami̇de Z. Şenyuva, Tuncel Özden, Deni̇z Yurtsever Sarica

Turkish Journal of Chemistry

The development of a sensitive automated method for residue control of oxytetracycline (OTC) in cured meat (soudjouk) is described. The principle steps involve the extraction of OTC from cured meat in the presence of citric acid with nitric acid, methanol and de-ionized water, and then the determination by HPLC. In HPLC, Hypersil BDC C18 column was used and OTC was separated at 24 ^{o}C using a mobile phase of H_2O (pH=2.10 with H_2SO_4): ACN (85:15, v/v) at a flow rate of 1.5 ml/min. A variable wavelength detector was set at 360 nm. The detection limit of the method was calculated …


Investigation Of The Influence Of Thiocarbamide In The Process Of Carbamide Deparaffinization, Sevi̇l Veli̇yeva Jan 2000

Investigation Of The Influence Of Thiocarbamide In The Process Of Carbamide Deparaffinization, Sevi̇l Veli̇yeva

Turkish Journal of Chemistry

The influence of thiocarbamide in the process of carbamide dewaxing was investigated. The dependence of separated paraffins on the quantity of thiocarbamide was examined experimentally. It was determined that the separation of paraffins becomes equal to zero when moles of carbamide and thiocarbamide in water-isopropyl alcohol solution are equal. The low-temperature qualities (the temperature of dimness and freezing) of dewaxed fuels were also examined. By using infrared spectroscopy methods, the compound of received paraffins was investigated.


Biostratigraphic Data (Mammalia And Palynology) From The Upper Miocene İncesu Formation At Düzyayla (Hafik-Sivas, Central Anatolia), Funda Akgün, Tanju Kaya, Ann Forsten, Zeki̇ Atalay Jan 2000

Biostratigraphic Data (Mammalia And Palynology) From The Upper Miocene İncesu Formation At Düzyayla (Hafik-Sivas, Central Anatolia), Funda Akgün, Tanju Kaya, Ann Forsten, Zeki̇ Atalay

Turkish Journal of Earth Sciences

The Upper Miocene İncesu formation, widely exposed in Düzyayla (Hafik-Sivas), consists of mudstones, conglomerates, lacustrine limestones and lignite. The İncesu formation overlies the gypsiferous Hafik formation of controversial Middle Miocene or Oligocene ages. The mammalian fauna of the lignite horizon includes Hipparion sp., Ceratotherium neumayri (Osborn), Deinotherium giganteum Kaup, Choerolophodon pentelici (Gaudry & Lartet), Adcrocuta cf. eximia (Roth & Wagner), Oioceros wegneri Andree, Helladotherium duvernoyi Gaudry & Lartet and Microstonyx erymanthius (Roth & Wagner), which indicate a Turolian (Late Miocene) age. The palynological assemblage of the lignite is apparently represented by 27 genera and 39 species. Four genera and four …


Front Matter Jan 2000

Front Matter

Journal of the Minnesota Academy of Science

No abstract provided.


Mining Geology Of Coals In Western Kentucky, Stephen F. Greb, David A. Williams Jan 2000

Mining Geology Of Coals In Western Kentucky, Stephen F. Greb, David A. Williams

Map and Chart--KGS

Each of the most heavily mined coal seams in the Western Kentucky Coal Field, as indicated by analyses, mine visits, and discussions with mine inspectors and engineers, has its own roof and floor characteristics. Also, because roof rocks above several of the seams are laterally continuous (especially in the Carbondale Formation), roof characteristics related to rock type are often widespread and continuous between mines. This chart discusses the mining geology of three western Kentucky coal beds, highlighted on the stratigraphic column shown in Figure 1.

Additional mining obstacles that can affect all coal beds and roof strata are (1) tectonic …


Quality Characteristics Of The Springfield Coal In Western Kentucky, Cortland F. Eble Jan 2000

Quality Characteristics Of The Springfield Coal In Western Kentucky, Cortland F. Eble

Map and Chart--KGS

Thickness and quality data from the Kentucky Coal Resources Information System (KCRIS) for the Springfield coal bed are summarized in this chart. Parameter averages and range of values are presented in the two tables, and average values are displayed graphically by county.


Regional Subsurface Geologic Cross Sections Of The Mississippian System, Appalachian Basin, Eastern Kentucky, David C. Harris, Thomas N. Sparks Jan 2000

Regional Subsurface Geologic Cross Sections Of The Mississippian System, Appalachian Basin, Eastern Kentucky, David C. Harris, Thomas N. Sparks

Map and Chart--KGS

This series of 14 regional cross sections illustrates subsurface stratigraphic correlations of Mississippian (upper Carboniferous) rocks in the Appalachian Basin of eastern Kentucky. These cross sections were constructed as part of a regional stratigraphic study of the Mississippian "Big Lime," a major oil- and gas-producing formation. The series illustrates 10 dip-oriented and 4 strike-oriented lines, extending from the Slade Formation outcrop belt on the northwest, to the state borders on the east and south. Stratigraphic and structural versions are shown for each section to better illustrate thickness and structural variations. These cross sections served as the regional framework during collection …


Quality Characteristics Of The Lower Elkhorn Coal Bed In Eastern Kentucky, Cortland F. Eble Jan 2000

Quality Characteristics Of The Lower Elkhorn Coal Bed In Eastern Kentucky, Cortland F. Eble

Map and Chart--KGS

Thickness and quality data from the Kentucky Coal Resources Information System (KCRIS) are summarized in this chart for the Lower Elkhorn coal bed (and equivalents). Parameter averages and ranges of values are presented in the two tables, and average values are displayed graphically by county.


Geologic Map Of Kentucky, Garland R. Dever Jr., M. C. Noger Jan 2000

Geologic Map Of Kentucky, Garland R. Dever Jr., M. C. Noger

Map and Chart--KGS

This map shows the geologic age of rocks and sediments at the surface in Kentucky. Sedimentary rocks, deposited from about 465 to 290 million years ago during the Ordovician, Silurian, Devonian, Mississippian, and Pennsylvanian Periods, crop out across the state. The rocks mainly consist of shale, limestone, sandstone, and siltstone. As shown in the cross sections, these surface rocks are underlain by older unexposed rocks of Precambrian, Cambrian, and Ordovician age.

Small bodies of igneous rocks were intruded into the state's bedrock about 270 million years ago during the Permian Period. They crop out in Elliott County of northeastern Kentucky, …


Generalized Geologic Bedrock Conditions As Related To Solid-Waste Landfills In Kentucky, Martin C. Noger Jan 2000

Generalized Geologic Bedrock Conditions As Related To Solid-Waste Landfills In Kentucky, Martin C. Noger

Map and Chart--KGS

This map is not intended to be used for selecting individual landfill sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions throughout the state that affect the selection of solid-waste disposal sites.


Coal Resources Of The Fire Clay Coal Zone In Eastern Kentucky, Ernest E. Thacker, Gerald A. Weisenfluh, Jeffery A. Esterle, Stephen F. Greb, John K. Hiett Jan 2000

Coal Resources Of The Fire Clay Coal Zone In Eastern Kentucky, Ernest E. Thacker, Gerald A. Weisenfluh, Jeffery A. Esterle, Stephen F. Greb, John K. Hiett

Map and Chart--KGS

This chart is one of a series that shows the regional characteristics of the Fire Clay coal zone. The maps and charts were prepared as part of the U.S. Geological Survey's National Coal Assessment Program, which compiles regional maps and databases that provide a comprehensive assessment of the most important coal beds in the nation. Within this coal zone, the Fire Clay coal is the most economically important bed and is one of the leading producers in the state of Kentucky. The Fire Clay coal contains a flint-clay parting that is believed to be of volcanic origin. The widespread occurrence …


Total Coal Thickness Of The Upper Elkhorn No. 3a Coal (Lower Bed) In Eastern Kentucky, Jeffery A. Esterle, Ernest E. Thacker, Gerald A. Weisenfluh Jan 2000

Total Coal Thickness Of The Upper Elkhorn No. 3a Coal (Lower Bed) In Eastern Kentucky, Jeffery A. Esterle, Ernest E. Thacker, Gerald A. Weisenfluh

Map and Chart--KGS

This map is one of a series that shows the regional characteristics of the Upper Elkhorn No. 3 coal zone. The maps were prepared as part of the U.S. Geological Survey's National Coal Assessment Program, which compiles regional maps and databases that provide a comprehensive assessment of the most important coal beds in the nation. The Upper Elkhorn No. 3 coal zone has been one of the leading producers in the state of Kentucky and, in some areas, contains very high-quality coal. The zone is composed of a number of distinct coal beds that merge in some areas to form …


Effects Of Longwall Mining On Hydrogeology, Leslie County, Kentucky Part 3: Post-Mining Conditions, Shelley Minns Hutcheson, James A. Kipp, James S. Dinger, Daniel I. Carey, Lyle V.A. Sendlein, Gregory L. Secrist Jan 2000

Effects Of Longwall Mining On Hydrogeology, Leslie County, Kentucky Part 3: Post-Mining Conditions, Shelley Minns Hutcheson, James A. Kipp, James S. Dinger, Daniel I. Carey, Lyle V.A. Sendlein, Gregory L. Secrist

Report of Investigations--KGS

The effects of longwall coal mining on hydrology in the Eastern Kentucky Coal Field have been investigated since 1991. The study area is in the Edd Fork watershed in southern Leslie County, over Shamrock Coal Company's Beech Fork Mine. Longwall panels approximately 700 ft wide are separated by three-entry gateways that are approximately 200 ft wide. The mine is operated in the Fire Clay (Hazard No. 4) coal; overburden thickness ranges from 300 to 800 ft. Mining began in panel 1 in September 1991 and concluded with panel 8 in September 1994. Long-term monitoring consisting of a network of piezometers …


The Effect Of Turfgrass Maintenance On Surface-Water Quality In A Suburban Watershed, Inner Blue Grass, Kentucky, R. Michael Williams, James S. Dinger, Andrew J. Powell, Dwayne R. Edwards Jan 2000

The Effect Of Turfgrass Maintenance On Surface-Water Quality In A Suburban Watershed, Inner Blue Grass, Kentucky, R. Michael Williams, James S. Dinger, Andrew J. Powell, Dwayne R. Edwards

Report of Investigations--KGS

Nutrients and pesticides applied during routine maintenance or establishment of turfgrass could result in nonpoint-source pollution. Nutrient and pesticide concentrations in water exiting a turfgrass management area in the Sinking Creek watershed, a suburban watershed in the Inner Blue Grass Region of central Kentucky, were monitored. This watershed was selected because it contains multiple land uses: agricultural, residential, and recreational (golf course).

A survey was conducted to determine the extent to which lawn-care products are used in the residential sector of the watershed. For the golf-course portion, the golf-course superintendent recorded chemical application daily.

Runoff from the golf course was …


Coal Resources Of The Upper Elkhorn No. 3a Coal (Lower Bed) In Eastern Kentucky, Jeffery A. Esterle, Ernest E. Thacker, Gerald A. Weisenfluh, John K. Hiett Jan 2000

Coal Resources Of The Upper Elkhorn No. 3a Coal (Lower Bed) In Eastern Kentucky, Jeffery A. Esterle, Ernest E. Thacker, Gerald A. Weisenfluh, John K. Hiett

Map and Chart--KGS

This map is one of a series that shows the regional characteristics of the Upper Elkhorn No. 3 coal zone. The maps were prepared as part of the U.S. Geological Survey's National Coal Assessment Program, which compiles regional maps and databases that provide a comprehensive assessment of the most important coal beds in the nation. The Upper Elkhorn No. 3 coal zone has been one of the leading producers in the state of Kentucky and, in some areas, is of very high quality. Bed stratigraphy within the Upper Elkhorn No. 3 zone and coal thickness of the No. 3A coal …


Overview Of Environmental Regulations That Affect Coal Combustion, Cortland F. Eble Jan 2000

Overview Of Environmental Regulations That Affect Coal Combustion, Cortland F. Eble

Information Circular--KGS

Environmental regulations have had, and continue to have, an effect on the combustion of coal. These regulations largely affect the electric utility industry, the largest consumer of domestic coal, but they ultimately affect everyone, because we all use electricity, and the cost of compliance is usually passed on to the consumer, resulting in higher electric bills.


Blending Hf Radar And Model Velocities In Monterey Bay Through Normal Mode Analysis, B. L. Lipphardt Jr., A. D. Kirwan Jr., C. E. Grosch, J. K. Lewis, J. D. Paduan Jan 2000

Blending Hf Radar And Model Velocities In Monterey Bay Through Normal Mode Analysis, B. L. Lipphardt Jr., A. D. Kirwan Jr., C. E. Grosch, J. K. Lewis, J. D. Paduan

CCPO Publications

Nowcasts of the surface velocity field in Monterey Bay are made for the period August 1-9, 1994, using HF radar observations blended with results from a primitive equation model. A spectral method called normal mode analysis was used. Objective spatial and temporal filtering were performed, and stream function, velocity potential, relative vorticity, and horizontal divergence were calculated over the domain. This type of nowcasting permits global spectral analysis of mode amplitudes, calculation of enstrophy, and additional analyses using tools like empirical orthogonal functions. The nowcasts reported here include open boundary flow information from the numerical model. Nowcasts using no open …


Multi-Phase Discrete Particle Swarm Optimization, Buthainah Sabeeh No'man Al-Kazemi, Chilukuri K. Mohan Jan 2000

Multi-Phase Discrete Particle Swarm Optimization, Buthainah Sabeeh No'man Al-Kazemi, Chilukuri K. Mohan

Electrical Engineering and Computer Science - All Scholarship

This paper describes a successful adaptation of the Particle Swarm Optimization algorithm to discrete optimization problems. In the proposed algorithm, particles cycle through multiple phases with differing goals. We also exploit hill climbing. On benchmark problems, this algorithm outperforms a genetic algorithm and a previous discrete PSO formulation.


Nonstationary Panels, Cointegration In Panels And Dynamic Panels: A Survey, Badi H. Baltagi, Chihwa Kao Jan 2000

Nonstationary Panels, Cointegration In Panels And Dynamic Panels: A Survey, Badi H. Baltagi, Chihwa Kao

Center for Policy Research

This paper provides an overview of topics in nonstationary panels: panel unit root tests, panel cointegration tests, and estimation of panel cointegration models. In addition it surveys recent developments in dynamic panel data models.


Nonparametric Bayes Estimation Of Contamination Levels Using Observations From The Residual Distribution, Paul H. Kvam, Ram C. Tiwari, Jyoti N. Zalkikar Jan 2000

Nonparametric Bayes Estimation Of Contamination Levels Using Observations From The Residual Distribution, Paul H. Kvam, Ram C. Tiwari, Jyoti N. Zalkikar

Department of Math & Statistics Faculty Publications

A nonparametric Bayes estimator of the survival function is derived for right censored data where additional observations from the residual distribution are available. The estimation is motivated by data on contamination concentrations for chromium from one of the EPA's toxic waste sites. The residual sample can be produced by hot spot sampling, where only samples above a given threshold value are collected. The Dirichlet process is used to formulate prior information about the chromium contamination, and we compare the Bayes estimator of the mean concentration level to other estimators currently considered by the EPA and other sources. The Bayes estimator …


Test 1782c: Challenger Mt 645 Diesel, Nebraska Tractor Test Lab Jan 2000

Test 1782c: Challenger Mt 645 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1781c: Challenger Mt 635 Diesel, Nebraska Tractor Test Lab Jan 2000

Test 1781c: Challenger Mt 635 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.