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1998

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Articles 1891 - 1920 of 2574

Full-Text Articles in Physical Sciences and Mathematics

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer Jan 1998

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer

Journal of the Arkansas Academy of Science

Sections and subsections of the Interior Highlands of Arkansas and Oklahoma are redefined, mapped and briefly summarized. The map was produced to support the Ozark- Ouachita Highlands Assessment (OOHA), being conducted by the USDA Forest Service. It revises the USDA Forest Service map "Ecological units of the eastern United States, first approximation" by Keys et al. (1995) and the earlier maps of the natural divisions of Arkansas (Foti, 1974; Foti, 1976; Pell, 1983) to reflect new knowledge and to achieve consistency with units recognized in Missouri. Four sections (natural divisions) are defined as opposed to the three of the previous …


Parallel Probabilistic Computations On A Cluster Of Workstations, Atanas Radenski, Andrew Vann, Boyana Norris Jan 1998

Parallel Probabilistic Computations On A Cluster Of Workstations, Atanas Radenski, Andrew Vann, Boyana Norris

Mathematics, Physics, and Computer Science Faculty Books and Book Chapters

Probabilistic algorithms are computationally intensive approximate methods for solving intractable problems. Probabilistic algorithms are excellent candidates for cluster computations because they require little communication and synchronization. It is possible to specify a common parallel control structure as a generic algorithm for probabilistic cluster computations. Such a generic parallel algorithm can be glued together with domain-specific sequential algorithms in order to derive approximate parallel solutions for different intractable problems.

In this paper we propose a generic algorithm for probabilistic computations on a cluster of workstations. We use this generic algorithm to derive specific parallel algorithms for two discrete optimization problems: the …


The Eigenfunctions Of A Certain Composition Operator, Valentin Matache Jan 1998

The Eigenfunctions Of A Certain Composition Operator, Valentin Matache

Mathematics Faculty Publications

The composition operator on the classical Hardy space H2, induced by a hyperbolic disk automorphism is considered. It is investigated when a H2-function induces under the given operator a minimal invariant cyclic subspace. Theorems where we use the behaviour of this function in the neighbourhood of the fixed points of the hyperbolic automorphism in order to decide if the cyclic subspace mentioned above is minimal invariant or not, are obtained. The inner eigenfunctions of the operator under consideration are characterized.


Use Of The Magnetic Field Generated By The Internal Distribution Of Injected Currents For Electrical Impedance Tomography (Mr-Eit), Y. Zi̇ya İder, Özlem Bi̇rgül Jan 1998

Use Of The Magnetic Field Generated By The Internal Distribution Of Injected Currents For Electrical Impedance Tomography (Mr-Eit), Y. Zi̇ya İder, Özlem Bi̇rgül

Turkish Journal of Electrical Engineering and Computer Sciences

In two dimensional conventional Electrical Impedance Tomography (EIT), volume conductor is probed by means of injected currents, and peripheral voltage measurements are used as input to the reconstruction algorithm. The current that flows in the 2D object creates magnetic fields that are perpendicular to the plane of imaging. Such magnetic fields can be measured using magnetic resonance tomography. In this study, use of this magnetic field generated by the injected currents, for the purpose of reconstructing the conductivity distribution, is studied. Sensitivity matrix relating the magnetic field to the element conductivities is calculated using the Finite Element Method and Biot-Savart …


The Relation Between Dislocation Density And Crystal Crosscut In \Beta-Sn Grown By Modified Bridgman Method, Bahattin Düzgün, İbrahim Karaman, Nazım Uçar Jan 1998

The Relation Between Dislocation Density And Crystal Crosscut In \Beta-Sn Grown By Modified Bridgman Method, Bahattin Düzgün, İbrahim Karaman, Nazım Uçar

Turkish Journal of Physics

Crystals $\beta$-Sn are grown from ingots of 99.99\% purity by modified Bridgman method under $10^{-3}$ torr pressure and oriented by Laue back reflection method. The relation between crystal crosscut and dislocation density calculated using etch hillock technique is investigated. It is found that the dislocation density increases with increasing crystal crosscut.


Study Of Magnetic Non-Uniformities In Yttrium-Iron Garnet By The Measuring Method Of Magneto-Optical Susceptibility, Komil Mukimov, Odil Ochilov, Makhset Khalmuratov, Asror Ramazanov, Ulpash Mirzakulova Jan 1998

Study Of Magnetic Non-Uniformities In Yttrium-Iron Garnet By The Measuring Method Of Magneto-Optical Susceptibility, Komil Mukimov, Odil Ochilov, Makhset Khalmuratov, Asror Ramazanov, Ulpash Mirzakulova

Turkish Journal of Physics

Study of magnetic non-uniformities in yttrium-iron garnet by the measuring in method of magneto-optical susceptibility in laser beam with the wave length of \lambda = 1.15 \mu m.


Infrared Absorption Study Of Potassium-Boro-Vanadate-Iron Glasses, Dinesh K. Kanchan, Harshvadan R. Panchal Jan 1998

Infrared Absorption Study Of Potassium-Boro-Vanadate-Iron Glasses, Dinesh K. Kanchan, Harshvadan R. Panchal

Turkish Journal of Physics

The IR studies have been made in the K_2O-B_2O_3-V_2O_5-Fe_2O_3 glass system. The increase in intensity and shifting of vibrational bands towards lower wave number at 1400-1350 cm^{-1}, 1200 cm^{-1} and 100-940 cm^{-1} in IR spectra have been ascribed to the formation of BO_3 to BO_4 and VO_5 to VO_4 tetrahedra along with the formation of non-bridging oxygens attached to boron and vanadium. In heat-treated glass samples, many new vibrational bands have been observed which were however, absent in the untreated samples. The preservation of the 1020 cm^{-1} band assigned to V=O bond suggests that K_2O shows the preference for borate …


Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş Jan 1998

Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş

Turkish Journal of Physics

In this work, the bulk modulus values for liquid alkali metal alloys near melting point are studied in the framework of the Gibbs-Bogoliubov method. We use the local Heine-Abarenkov pseudopotential and Ichimaru-Utsumi screening function in these alloys. The results are compared with experimental and theoretical results.


High-Power Diffusion Cooling Planar Waveguide Co_{2} Laser, E. Taal, M. S. Kiliçkaya Jan 1998

High-Power Diffusion Cooling Planar Waveguide Co_{2} Laser, E. Taal, M. S. Kiliçkaya

Turkish Journal of Physics

A diffusion-cooled CO_{2} laser using a coaxial waveguide is investigated theoretically. The resonator extracting the laser beam consits of two annular plane mirrors enclosing the two ends of the waveguide. A theoretical resonator model based on the vector modes of propagation in a dielectric coaxial waveguide is described.


A Phase Diagram Of The Nematic, Smectic A And Smectic C Phases In Liquid Crystals, S. Sali̇hoğlu, H. Yurtseven Jan 1998

A Phase Diagram Of The Nematic, Smectic A And Smectic C Phases In Liquid Crystals, S. Sali̇hoğlu, H. Yurtseven

Turkish Journal of Physics

In this study we have obtained a phase diagram for the nematic, smectic A and smectic C phases in liquid crystals. For this phase diagram we have studied two different mean field models for a mixture of liquid crystalline system. In our first model we consider the NC and AC transitions as first order, and the NA transition as a second order. In our second model we consider the NC and NA transitions as first order, and the AC transition as a second order.


Doping Effects Of Ga And Te On The Kinetic Coefficients Of Rhombohedral And Cubic Phases Of Ge_{1-X} Ga_X Te Solid Solution Alloys, T. Atalay, M.H. Akperov Jan 1998

Doping Effects Of Ga And Te On The Kinetic Coefficients Of Rhombohedral And Cubic Phases Of Ge_{1-X} Ga_X Te Solid Solution Alloys, T. Atalay, M.H. Akperov

Turkish Journal of Physics

In this study Ga and Te doping effects on the kinetic parameters (thermo e.m.f., electrical conductivity, heat conductivity, Hall and Nernst-Ettingshausen coefficients) of the rhombohedral and cubic phases of Ge_{1-x} Ga_x Te (0 < x \leq 0,06) solid solutions has been investigated between 77-900 K temperature intervals. Increase in the amount of Te increases hole concentration and reduces lattice constant, whereas rhombohedral propeties of GeTe rises with increase of Ga concentration. The observed anomalies on the kinetic parameters may be explained qualitatively by the complexity of the Fermi surface shape and the zone model of GeTe which involves the seperation of the L extremums that is same for ``\alpha'', ``\beta'' and ``\gamma'' phases of the compound.


Alkaline Rocks And Geodynamics, Bernard Bonin Jan 1998

Alkaline Rocks And Geodynamics, Bernard Bonin

Turkish Journal of Earth Sciences

Origin of A-type alkali feldspar granites is currently the subject of a world-wide debate. Contrasting hypotheses have been proposed, which range from an entirely crustal origin to an almost complete mantle derivation. A-type alkali feldspar granites belong to either unimodal granite (rhyolite)-dominated association, or bimodal gabbro (basalt)-granite (rhyolite) suite. It is argued that (i) the ultimate mantle origin of basic to intermediate rocks is beyond doubt, (ii) highly evolved felsic rocks may be produced by other processes besides crustal involvement through anatexis and (iii) large volumes of felsic rocks are a normal and direct consequence of extensive crystal fractionation processes. …


Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 5 White/Beattys' Catchment (Dinninup), A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr Jan 1998

Results Of Investigations Into The Groundwater Response And Productivity Of High Water Use Agricultural Systems 1990-1997 5 White/Beattys' Catchment (Dinninup), A D. Smith, Richard J. George Dr, P R. Scott, D L. Bennett, R J. Rippon, G J. Orr

Resource management technical reports

High water use vegetation systems for salinity control were trialed on a 250 ha catchment located three km north-west of Dinninup, Western Australia. The catchment receives about 620 mm annual rainfall and 1500 mm annual evaporation. The catchment is characterised by slopes with gradients in excess of 5%, deep weathering (15-25 m to bedrock), active seepage in the valley (piezometric heads 204 m above ground surface) and high recharge (water table fluctuations of 1-4 m).


Approaches And Methodologies For The Synthesis Of Aromatic Natural Products, Christina A. Goudreau Jan 1998

Approaches And Methodologies For The Synthesis Of Aromatic Natural Products, Christina A. Goudreau

Honors Theses

Chemists have been captivated by the ability of most natural products to exhibit biological activity which in effect has made them very attractive to pharmaceutical companies. Many over-the-counter drugs such as aspirin were first extracted from natural products and are now an integral part of most of our lives. More importantly, certain drugs such as taxol, which is used to treat breast cancer, initially came from the bark of a yew tree. Extracting these substances from their natural source and using them medicinally at the demand of the consumers would result in the destruction of the natural habitat. Oftentimes, the …


Alternatives To Nitroprusside, William T. Hiscock Jan 1998

Alternatives To Nitroprusside, William T. Hiscock

Honors Theses

Any transition metal nitrosyl complex may release nitric oxide and thus has potential as a vasodilator. Nitroprusside, Na2[Fe(CN)5(NO)], is currently used, but dosages are limited because of the potential release of cyanide. Research in our group has been directed towards the synthesis of iron and ruthenium complexes containing the nitrosyl ligand and polypyridyl coligands such as 2,2-dipyridyl (bpy) and 2,2': 6',2"-terpyridine (tpy). These coligands are much less toxic than cyanide. Both [(bpy)(tpy)Fe(NO)]3+ and [(bpy)(tpy)Ru(NO)]3+ have been synthesized and characterized using infrared and ultraviolet spectroscopy, conductivity, and magnetic susceptibility. Along with the search for other possible polydentate coligands, is the search …


Soil Moisture Gradients And Controls On A Southern Appalachian Hillslope From Drought Through Recharge, J. Alan Yeakley, W. T. Swank, L. W. Swift, G. M. Hornberger, H. H. Shugart Jan 1998

Soil Moisture Gradients And Controls On A Southern Appalachian Hillslope From Drought Through Recharge, J. Alan Yeakley, W. T. Swank, L. W. Swift, G. M. Hornberger, H. H. Shugart

Environmental Science and Management Faculty Publications and Presentations

Soil moisture gradients along hillslopes in humid watersheds, although indicated by vegetation gradients and by studies using models, have been difficult to confirm empirically. While soil properties and topographic features are the two general physio-graphic factors controlling soil moisture on hillslopes, studies have shown conflicting results regarding which factor is more important. The relative importance of topographic and soil property controls was examined in an upland forested watershed at the Coweeta Hydrologic Laboratory in the southern Appalachian mountains. Soil moisture was measured along a hillslope transect with a mesic-to-xeric forest vegetation gradient over a period spanning precipitation extremes. The hillslope …


The Synthesis And Characterization Of Monometallic And Bimetallic Pd-Pnp Complexes, Lorinda Asmus Jan 1998

The Synthesis And Characterization Of Monometallic And Bimetallic Pd-Pnp Complexes, Lorinda Asmus

Honors Theses, 1963-2015

The bridging ligand, 2-[bis(diphenylphosphino)methyl]pyridine (PNP), is ideal for synthesizing mono- and bi-metallic catalysts due to its potential to be bidentate (P-P or P-N) or tridentate and its ability to bind to one or more metals. Three Pd-PNP complexes, [Pd(PNP)2]+2 (1) and two complexes resulting from the removal of one or two methine pronouns (2 and 3), have been synthesized. The removal of one methine proton changes the PNP bidentate binding mode. In complex 1 and 3, the two PNP ligands are P-P bound. However, upon the removal of one methine proton, one …


Counting Cards: Combinatorics, Group Theory, And Probability In War, Angela J. Chappell Jan 1998

Counting Cards: Combinatorics, Group Theory, And Probability In War, Angela J. Chappell

Honors Theses, 1963-2015

My project involved taking a look at the card game War, searching for patterns which develop in the game, and then looking for Mathematical explanations for those patterns. The project began when my advisor, Professor Marc Brodie, was playing War with his children and began to notice patterns and ask questions about them. The questions I set out to answer were: What is the probability of playing a game of war in which a loop develops? If we know the size of the deck we are using, can we determine what loop lengths are possible? How are cards cycling between …


Multicolor Fringe Projection System With Enhanced 3-D Reconstruction Of Surfaces, Bernard S. Gilbert, Joel H. Blatt Jan 1998

Multicolor Fringe Projection System With Enhanced 3-D Reconstruction Of Surfaces, Bernard S. Gilbert, Joel H. Blatt

Aerospace, Physics, and Space Science Faculty Publications

Most optical topology systems use a single wavelength laser for projection, using a swept spot, a moving line, or a projected grating. In a typical projected grating system, the gratings are shifted and a series of images are used to recover the 3-D shape of the target. When the series of images is analyzed in the normal phase shift manner, the resulting 2-D phase map typically has phase unwrapping problems due to noise and Nyquist limits. Surfaces with large vertical discontinuities present the biggest problem in 3-D shape recovery. This paper looks at simultaneously projecting multiple wavelengths onto a surface …


Test 1702s - S190: New Holland 3930 8x8 Diesel, Nebraska Tractor Test Lab Jan 1998

Test 1702s - S190: New Holland 3930 8x8 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …


Test 1744: John Deere 8100t Diesel 16-Speed, Nebraska Tractor Test Lab Jan 1998

Test 1744: John Deere 8100t Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …


Nebraska Summary: S326 Case-Ih C70, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S326 Case-Ih C70, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …


Nebraska Summary 321: Massey Ferguson 8280 Diesel 18-Speed, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary 321: Massey Ferguson 8280 Diesel 18-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Nebraska Summary 277: Massey-Ferguson 4235 Diesel 18-Speed, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary 277: Massey-Ferguson 4235 Diesel 18-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Test 1896: Case Ih Cx 80/C 80 Diesel, Nebraska Tractor Test Lab Jan 1998

Test 1896: Case Ih Cx 80/C 80 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1779: Challenger Mt 425 Diesel, Nebraska Tractor Test Lab Jan 1998

Test 1779: Challenger Mt 425 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1803: Kubota M6800dt Diesel, Nebraska Tractor Test Lab Jan 1998

Test 1803: Kubota M6800dt Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1774: Zetor 10641/Zetor 10741 Diesel, Nebraska Tractor Test Lab Jan 1998

Test 1774: Zetor 10641/Zetor 10741 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Nebraska Summary: S283 New Holland 9682, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S283 New Holland 9682, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …


Nebraska Summary: S282 New Holland 9482, Nebraska Tractor Test Lab Jan 1998

Nebraska Summary: S282 New Holland 9482, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …