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2000

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Articles 31 - 60 of 2952

Full-Text Articles in Physical Sciences and Mathematics

Electrical Feedthrough And Its Preparation, Leonard E. Peck, Timothy S. Romano, Tom K. Evans, Gary B. Hughes, Karl H. Neumann Dec 2000

Electrical Feedthrough And Its Preparation, Leonard E. Peck, Timothy S. Romano, Tom K. Evans, Gary B. Hughes, Karl H. Neumann

Statistics

An electrical feedthrough (34) is prepared by furnishing an aluminum oxide feedthrough plate (70) and at least one feedthrough pin (80) having a length greater than the thickness of the feedthrough plate (70). A pin bore (78) is formed through the feedthrough plate (70) for each feedthrough pin (80). Each pin bore (78) has a pin bore (78) size greater than the feedthrough pin (80) size, preferably by an amount no greater than that required to permit the penetration of a brazing metal (88) between the pin bore (78) and the feedthrough pin (80). Each feedthrough pin (80) is inserted …


Measurement Of The W Boson Mass Using Large Rapidity Electrons, B. Abbott, Gregory R. Snow, D0 Collaboration Dec 2000

Measurement Of The W Boson Mass Using Large Rapidity Electrons, B. Abbott, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We present a measurement of the W boson mass using data collected by the DØ. experiment at the Fermilab Tevatron during 1994–1995. We identify W bosons by their decays to en final states where the electron is detected in a forward calorimeter. We extract the W boson mass MW by fitting the transverse mass and transverse electron and neutrino momentum spectra from a sample of 11 089 Weν decay candidates. We use a sample of 1687 dielectron events, mostly due toZee decays, to constrain our model of the detector response. Using the forward …


Low-Frequency Crossover Of The Fractional Power-Law Conductivity In Srruo3, J. S. Dodge, Christopher P. Weber, J. Corson, J. Orenstein, Z. Schlesinger, J. W. Reiner, M. R. Beasley Dec 2000

Low-Frequency Crossover Of The Fractional Power-Law Conductivity In Srruo3, J. S. Dodge, Christopher P. Weber, J. Corson, J. Orenstein, Z. Schlesinger, J. W. Reiner, M. R. Beasley

Physics

We combine the results of terahertz time-domain spectroscopy with far-infrared transmission and reflectivity to obtain the conductivity of SrRuO 3 over an unprecedented continuous range in frequency, allowing us to characterize the approach to zero frequency as a function of temperature. We show that the conductivity follows a simple phenomenological form, with an analytic structure fundamentally different from that predicted by the standard theory of metals.


Sag Testing Of Dairy Farm Milking Equipment, V. J. Gosbell, V. Smith, D. A. Robinson, B. S. Perera Dec 2000

Sag Testing Of Dairy Farm Milking Equipment, V. J. Gosbell, V. Smith, D. A. Robinson, B. S. Perera

Faculty of Informatics - Papers (Archive)

Sags are widely reported as being one of the worst power quality problems and are particularly common in rural areas. Automated milking equipment on dairy farms are thus very susceptible to malfunction by sags. In assessing the relative cost/benefits of sag mitigation in the dairy or the supply network it is important to know the dairy equipment immunity level. It is shown how a harmonic generator can be used to determine this information. Testing revealed that the motor contactor was a critical component as it was unable to ride through a 40% sag longer than about 0.5 seconds. The milking …


On Amicable Sequences And Orthogonal Designs, S. Georgiou, C. Koukouvinos, Jennifer Seberry Dec 2000

On Amicable Sequences And Orthogonal Designs, S. Georgiou, C. Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper we give a general theorem which can be used to multiply the length of amicable sequences keeping the amicability property and the type of the sequences. As a consequence we have that if there exist two, four or eight amicable sequences of length m and type (al, a2), (al, a2, a3, a4) or (al, a2, ... , a8) then there exist amicable sequences of length ℓ ≡ 0 (mod m) and of the same type. We also present a theorem that produces a set of 2v amicable sequences from a set of v (not necessary amicable) sequences …


Stochastic Dynamics Of Systems With Memory (Stochastic Analysis Seminar, University Of Oxford), Salah-Eldin A. Mohammed Dec 2000

Stochastic Dynamics Of Systems With Memory (Stochastic Analysis Seminar, University Of Oxford), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

No abstract provided.


Ga-Doped Zno Films Grown On Gan Templates By Plasma-Assisted Molecular-Beam Epitaxy, H. J. Ko, Yanfang Chen, S. K. Hong, H. Wenisch, T. Yao, David C. Look Dec 2000

Ga-Doped Zno Films Grown On Gan Templates By Plasma-Assisted Molecular-Beam Epitaxy, H. J. Ko, Yanfang Chen, S. K. Hong, H. Wenisch, T. Yao, David C. Look

Physics Faculty Publications

We have investigated the structural and optical properties of Ga-doped ZnO films grown on GaN templates by plasma-assisted molecular-beam epitaxy. The carrier concentration in Ga-doped ZnO films can be controlled from 1.33×1018/cm3 to 1.13×1020/cm3. Despite high Ga incorporation, the linewidth of (0002) ω-rocking curves of Ga-doped ZnO films still lies in the range from 5 to 15 arc min. Photoluminescence (PL) spectra of Ga-doped ZnO films show dominant near-bandedge emission with negligibly weak deep-level emission, independent of carrier concentration. The PL spectrum exhibits a new emission line at 3.358 eV, which corresponds to …


5. Burton Carl Anderson, Otto Vogl Dec 2000

5. Burton Carl Anderson, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


Faint Radio Sources And Star Formation History, Deborah B. Haarsma, R. B. Partridge, R. A. Windhorst, E. A. Richards Dec 2000

Faint Radio Sources And Star Formation History, Deborah B. Haarsma, R. B. Partridge, R. A. Windhorst, E. A. Richards

University Faculty Publications and Creative Works

The centimeter-wave luminosity of local radio galaxies correlates well with their star formation rate. We extend this correlation to surveys of high-redshift radio sources to estimate the global star formation history. The star formation rate found from radio observations needs no correction for dust obscuration, unlike the values calculated from optical and ultraviolet data. Three deep radio surveys have provided catalogs of sources with nearly complete optical identifications and nearly 60% complete spectroscopic redshifts: the Hubble Deep Field and Flanking Fields at 12h + 62°, the SSA13 field at 13h + 42°, and the V15 field at 14h + 52°. …


The Use Of Benthic Macroinvertebrates By Rainbow Trout (Oncorhynchus Mykiss) In Lake Ogallala, Nebraska, Tyler J. Pearson Dec 2000

The Use Of Benthic Macroinvertebrates By Rainbow Trout (Oncorhynchus Mykiss) In Lake Ogallala, Nebraska, Tyler J. Pearson

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Ecological And Physiological Factors Affecting Nesting Success Of Burrowing Owls In Buffalo Gap National Grassland, Randall L. Griebel Dec 2000

Ecological And Physiological Factors Affecting Nesting Success Of Burrowing Owls In Buffalo Gap National Grassland, Randall L. Griebel

School of Natural Resources: Dissertations, Theses, and Student Research

The western burrowing owl (Athene cunicularia hypugea) has been declining throughout much of its range, and in some areas, quite dramatically. In the Great Plains region, these declines appear to be closely associated with declines in prairie dog numbers. Most research to date has taken place on relatively small, fragmented prairie dog colonies. The objectives of this study were to analyze burrowing owl reproductive performance (i.e., clutch size, brood size, and number fledged), and nestling body condition in relation to nest level and colony level factors in Buffalo Gap National Grassland, South Dakota. Buffalo Gap contains large prairie …


The Prairie Naturalist Volume 32, No.4 December 2000 Dec 2000

The Prairie Naturalist Volume 32, No.4 December 2000

The Prairie Naturalist

LOCATING NESTS OF BIRDS IN GRASSLANDS FROM A MOBILE TOWER BLIND ▪ . T. F. Fondell, S. T. Hoekman, and L J. Ball

OBSERVATIONS ON SMALL MAMMALS RECOVERED FROM OWL PELLETS FROM NEBRASKA ▪ J J Huebschman, P. W Freeman, H. H. Genoways, and J A. Gubanyi

DlSTRIBUTION, HABITAT USE, AND NESTING SUCCESS OF HENSLOW'S SPARROW IN OKLAHOMA ▪ D. L. Reinking, D. A. Wiedenfeld, D. H. Wolfe, and R. W. Rohrbaugh, Jr.

REPRODUCTIVE SUCCESS OF PIPING PLOVERS ON ALKALI LAKES IN NORTH DAKOTA AND MONTANA ▪ R. K. Murphy, M. J. Rabenberg, M. L. Sondreal, B. R. Casler, and …


Water Current, Volume 32, No. 6, December 2000 Dec 2000

Water Current, Volume 32, No. 6, December 2000

Water Current Newsletter

Lake Classification Project Could Establish National Water Quality Ranking Procedure
From the Director: Profiling the Individuals and Efforts That Comprise the Water Center; Faculty Members Named to Administrative Posts
Meet the Faculty: David M. Admiraal; John C. Holz
Quality-Assessed Groundwater Pesticide Data Available Online
Groundwater Guardians
Pesticides Discovered in Ogallala Aquifer According to Recent USGS Study
Spring Semester Water Resources Seminar: Social Sciences Affect on Allocation of Water and Natural Resources
Nominations Solicited for 2001 Nebraska Water Conference
Water News Briefs
Congratulations to Our Winners
Avoid Fall Irrigation
TGF National Award Recipients
Our New Look
Watch Us on the Web …


Instrument Performance Enhancement And Modification Through An Extended Instrument Paradigm, Stephen L. Mahan Dec 2000

Instrument Performance Enhancement And Modification Through An Extended Instrument Paradigm, Stephen L. Mahan

Doctoral Dissertations

An extended instrument paradigm is proposed, developed and shown in various applications. The CBM (Chin, Blass, Mahan) method is an extension to the linear systems model of observing systems. In the most obvious and practical application of image enhancement of an instrument characterized by a time-invariant instrumental response function, CBM can be used to enhance images or spectra through a simple convolution application of the CBM filter for a resolution improvement of as much as a factor of two. The CBM method can be used in many applications. We discuss several within this work including imaging through turbulent atmospheres, or …


Questing For The Grail: Core Collapse Supernova Simulations With Boltzmann Neutrino Transport, Otis Earl Messer Dec 2000

Questing For The Grail: Core Collapse Supernova Simulations With Boltzmann Neutrino Transport, Otis Earl Messer

Doctoral Dissertations

The importance of exact neutrino transport in spherically symmetric core collapse supernova simulations is explored in this dissertation. The primary tool for these studies is the neutrino radiation hydrodynamics code AGILE-BOLTZTRAN (Mezzacappa & Bruenn 1993a,b,c; Mezzacappa & Messer 1998; Liebendörfer 2000). AGILE-BOLTZTRAN couples the solution of the Boltzmann equation for all three flavors of neutrinos and antineutrinos to a one-dimensional, implicit, adaptive grid hydrodynamics code. Emission, absorption, and scattering of neutrinos from nucleons and nuclei, neutrino-electron scattering, and pair production and annihilation are included as neutrino-matter couplings. Details of the code are described, including the equations solved and their finite …


Electronic Excitations In Metals And Semiconductors: Ab Initio Studies Of Realistic Many-Particle Systems, Wei Ku Dec 2000

Electronic Excitations In Metals And Semiconductors: Ab Initio Studies Of Realistic Many-Particle Systems, Wei Ku

Doctoral Dissertations

Electronic excitations in metals and semiconductors, measured through inelastic x-ray scattering, electronic energy-loss spectroscopy, and angle-resolved photoemission, provide valuable information about the intrinsic many-body interactions between electrons in the crystal environment. These dynamical interactions are usually analyzed with intuitive simple models. With the problems studied, which correspond to linear response and quasi-particle excitation, it will be shown that ab initio approaches not only can provide more realistic understanding of microscopic processes and mechanisms, but also result in new theoretical interpretations that resolve a number of remarkable "anomalies." Specifically, these problems include the dispersion of the plasmon lifetime in potassium, the …


Seaway: A Multi-Agent Decision-Support System For Naval Expeditionary Logistic Operations, Anthony Wood, Kym Jason Pohl, Justin Crawford, Mark Lai, John Fanshier, Ken Cudworth, Tom Tate, Hisham Assal, Shawn Pan, Jens G. Pohl Dec 2000

Seaway: A Multi-Agent Decision-Support System For Naval Expeditionary Logistic Operations, Anthony Wood, Kym Jason Pohl, Justin Crawford, Mark Lai, John Fanshier, Ken Cudworth, Tom Tate, Hisham Assal, Shawn Pan, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This report describes work performed by CDM Technologies Inc. in conjunction with the Collaborative Agent Design (CAD) Research Center of California Polytechnic State University (Cal Poly), San Luis Obispo, for the Office of Naval Research (ONR), on the SEAWAY experimental system for planning, gaming and executing maritime logistic operations from a sea base. SEAWAY incorporates three fundamental concepts that distinguish it from existing (i.e., legacy) command and control applications. First, it is a collaborative system in which computer-based agents assist human operators by monitoring, analyzing and reasoning about events in near real-time. Second, SEAWAY includes an ontological model of the …


Osl Dating Supports "High" Sedimentation Rates In Central Arctic Ocean, Martin Jakobsson, Andrew Murray, Jan Backman, Reidar Lovlie Dec 2000

Osl Dating Supports "High" Sedimentation Rates In Central Arctic Ocean, Martin Jakobsson, Andrew Murray, Jan Backman, Reidar Lovlie

Center for Coastal and Ocean Mapping

No abstract provided.


Computational Geometry Column 40, Joseph O'Rourke Dec 2000

Computational Geometry Column 40, Joseph O'Rourke

Computer Science: Faculty Publications

It has recently been established by Below, De Loera, and Richter-Gebert that finding a minimum size (or even just a small) triangulation of a convex polyhedron is NP-complete. Their 3SAT-reduction proof is discussed.


Combinatorial Approach To Planar Non-Colliding Robot Arm Motion Planning, Ileana Streinu Dec 2000

Combinatorial Approach To Planar Non-Colliding Robot Arm Motion Planning, Ileana Streinu

Computer Science: Faculty Publications

We propose a combinatorial approach to plan non-colliding motions for a polygonal bar-and-joint framework. Our approach yields very efficient deterministic algorithms for a category of robot arm motion planning problems with many degrees of freedom, where the known general roadmap techniques would give exponential complexity. It is based on a novel class of one-degree-of-freedom mechanisms induced by pseudo triangulations of planar point sets, for which we provide several equivalent characterization and exhibit rich combinatorial and rigidity theoretic properties. The main application is an efficient algorithm for the Carpenter's Rule Problem: convexify a simple bar-and-joint planar polygonal linkage using only non …


Modeling High-Frequency Seafloor Backscattering Of Gassy Sediments: The Eel River Margin Case, Luciano E. Fonseca, Larry A. Mayer Dec 2000

Modeling High-Frequency Seafloor Backscattering Of Gassy Sediments: The Eel River Margin Case, Luciano E. Fonseca, Larry A. Mayer

Center for Coastal and Ocean Mapping

Models of acoustic backscatter typically take into account two different processes: interface scattering and volume scattering. What happens to these two contributions when the sediment is charged with gas bubbles? For the interface backscatter contribution we adopted the model developed by Jackson et al. (1986), but added modifications to accommodate gas bubbles, which when present, even in very small quantities, can dominate the acoustic characteristics of the sediment. The model parameters that are affected by gas content are the density ratio, the sound speed ratio and the loss parameter. To a first approximation, the model roughness parameters are not influenced …


New Kinematic Models For Pacific‐North America Motion From 3 Ma To Present, Ii: Evidence For A “Baja California Shear Zone”, Timothy Dixon, Fred Farina, Charles Demets, Francisco Suarez-Vidal, John Fletcher, Bertha Marquez-Azua, M. Meghan Miller, Osvaldo Sanchez, Paul Umhoefer Dec 2000

New Kinematic Models For Pacific‐North America Motion From 3 Ma To Present, Ii: Evidence For A “Baja California Shear Zone”, Timothy Dixon, Fred Farina, Charles Demets, Francisco Suarez-Vidal, John Fletcher, Bertha Marquez-Azua, M. Meghan Miller, Osvaldo Sanchez, Paul Umhoefer

All Faculty Scholarship for the College of the Sciences

We use new models for present‐day Pacific‐North America motion to evaluate the tectonics of offshore regions west of the Californias. Vandenburg in coastal Alta California moves at the Pacific plate velocity within uncertainties (∼1 mm/yr) after correcting for strain accumulation on the San Andreas and San Gregorio‐Hosgri faults with a model that includes a viscoelastic lower crust. Modeled and measured velocities at coastal sites in Baja California south of the Agua Blanca fault, a region that most previous models consider Pacific plate, differ by 3–8 mm/yr, with coastal sites moving slower that the Pacific plate. We interpret these discrepancies in …


The John Muir Newsletter, Winter 2000/2001, The John Muir Center For Regional Studies Dec 2000

The John Muir Newsletter, Winter 2000/2001, The John Muir Center For Regional Studies

Muir Center Newsletters, 1981-2015

NEWS TER Was John Muir A Woodsman? by Jason Meijia, California (Editor's Note: The former director of the John Muir ■Center, R. H. Limbaugh, has submitted the following paper as an example of outstanding undergraduate "■research on John Muir.) hat is a woodsman? Several definitions are available. First, Webster's College Dictionary defines the term as "a person accustomed to life in the woods and skilled in the arts of the woods, as hunting or trapping." Secondly, a special operations organization, spECOps, with the United States Special Forces Veterans, provides global survival training and according to it, a modern "woodsman" should …


Predicted Land Use Changes In Agricultural Areas Of Wa And Resulting Impact On The Extent Of Dryland Salinity, C E. Mcconnell Dec 2000

Predicted Land Use Changes In Agricultural Areas Of Wa And Resulting Impact On The Extent Of Dryland Salinity, C E. Mcconnell

Resource management technical reports

An assessment of current and possible future land use in Western Australia was undertaken as part of the National Land and Water Resources Audit. This data was used to assess the impact of land use change on the future extent of salinity. It was found that in some areas there is real capacity for changing land use to impact on recharge to the watertable.


8 Miles And A Couple Of Antiparticles To Bridgewater State College, Edward Deveney Dec 2000

8 Miles And A Couple Of Antiparticles To Bridgewater State College, Edward Deveney

Bridgewater Review

No abstract provided.


Searches For Neutral Higgs Bosons In Quark-Antiquark Tau-Antitau Final States Using The Opal Detector At Lep, James Andrew Hocker '91 Dec 2000

Searches For Neutral Higgs Bosons In Quark-Antiquark Tau-Antitau Final States Using The Opal Detector At Lep, James Andrew Hocker '91

Doctoral Dissertations

Searches for neutral Higgs bosons have been performed with the OPAL detector at LEP. Approximately 170 /pb of e+e- collision data at a center-of-mass energy of 189 GeV have been used to search for the SM process e+e- to HZ as well as for the processes e+e- to hZ and e+e- to hA which occur in extended Higgs theories. The searches are sensitive to final states containing quarks and tau leptons, for which an artificial neural network for the identification of tau leptons was designed. The results have been combined with OPAL searches for other final states to obtain a …


Flow Near Submarine Canyons Driven By Constant Winds, Jun She, John M. Klinck Dec 2000

Flow Near Submarine Canyons Driven By Constant Winds, Jun She, John M. Klinck

CCPO Publications

Circulation over coastal submarine canyons driven by constant upwelling or downwelling wind stress is simulated and analyzed with a primitive equation ocean model. Astoria Canyon, on the west coast of North America, is the focus of this study, and model results are consistent with most major features of mean canyon circulation observed in Astoria Canyon. Near-surface flow crosses over the canyon, while a closed cyclone occurs within the canyon. Upwelling prevails within the canyon and is larger than wind-driven upwelling along the adjacent shelf break. Water rises from depths reaching 300 m to the canyon rim and, subsequently, onto the …


A Desktop Universe For The Introductory Astronomy Laboratory, Laurence A. Marschall, Glenn A. Snyder, Paul Richard Cooper Dec 2000

A Desktop Universe For The Introductory Astronomy Laboratory, Laurence A. Marschall, Glenn A. Snyder, Paul Richard Cooper

Physics and Astronomy Faculty Publications

What is a well-intentioned astronomy instructor to do? There is no argument that experience with the real world is desirable in any astronomy course, especially the introductory classes that fulfill the science distribution requirements at many colleges and universities. Though it is a simple matter to take students out of doors, show them the motions of the Sun, Moon, and stars, and have them squint for a few seconds at Saturn's rings through a telescope, these activities represent only a small portion of the subject matter of modern astronomy. It is simply not possible, given the constraints of time, weather, …


Improving Water Quality Through Bmps For Crop Production Systems Whole Farm Soil And Water Management, J. T. Gilmour, L. R. Frye, N. A. Slaton Dec 2000

Improving Water Quality Through Bmps For Crop Production Systems Whole Farm Soil And Water Management, J. T. Gilmour, L. R. Frye, N. A. Slaton

Technical Reports

The major objective of this demonstration project was to assess the usefulness of Global Positioning Systems/Geographic Information Systems (GPS/GIS), water testing, soil testing and yield monitoring in a whole farm water and soil management plan. An important part of this objective was to make recommendations to increase crop productivity and decrease the potential for surface water degradation through erosion and runoff at the farm. The farm was located on 2400 acres in the Bayou de View watershed in Monroe County, Arkansas. The farm lies approximately five miles southwest of the town of Brinkley straddling Highway 17 just south of its …


5. Burton Carl Anderson, Otto Vogl Dec 2000

5. Burton Carl Anderson, Otto Vogl

Otto Vogl

No abstract provided.