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1997

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Articles 1 - 30 of 2179

Full-Text Articles in Physical Sciences and Mathematics

Module Embedding, Atanas Radenski Dec 1997

Module Embedding, Atanas Radenski

Mathematics, Physics, and Computer Science Faculty Articles and Research

This paper proposes a code reuse mechanism called module embedding that enables the building of new modules from existing ones through inheritance, overriding of procedures, and overriding of types; the paper also describes an implementation scheme for this mechanism. Module embedding is beneficial when modules and classes are used in combination and need to be extended together, or when modules are more appropriate medium than classes.


The Potential Impact Of Marpol Annex Vi On The Design And Operation Of Oil Tankers, Pratomo Setyohadi Dec 1997

The Potential Impact Of Marpol Annex Vi On The Design And Operation Of Oil Tankers, Pratomo Setyohadi

World Maritime University Dissertations

No abstract provided.


Protection Of Bangladesh Waters Against Accidental Oil Pollution From Ships, Khondaker Md. Asaduzzaman Dec 1997

Protection Of Bangladesh Waters Against Accidental Oil Pollution From Ships, Khondaker Md. Asaduzzaman

World Maritime University Dissertations

Bangladesh, as being a flag, coastal and port state, has a genuine concern about the threat of oil pollution from marine transportation in its waters. However, her concern for accidental oil pollution from ships is not adequately matched by appropriate preventive and remedial measures. As a result, the country continues to be in an absolutely vulnerable position with respect to the dangers of oil pollution. This dissertation is a study of the need for and the ways of protecting the marine environment of Bangladesh from oil pollution incidents. The threats of accidental spills in Bangladesh waters are discussed and the …


New Topologies And Parallel Algorithms For Static Interconnection Networks., Srabani Sen Gupta Dr. Dec 1997

New Topologies And Parallel Algorithms For Static Interconnection Networks., Srabani Sen Gupta Dr.

Doctoral Theses

Many real-life applications in the areas of signal processing, image processing, etc., require a large amount of fast computations to be performed. Although high speed powerful processors are currently available due to the phenomenal advances in VLSI technology, the increasing demand for massive real-time computations can not be met just by a uniprocessor system. One way of achieving the goal of fast computation is through parallel processing. In parallel processing, a problem is broken into several subproblems, which are distributed among different processors so that each of the processors can perform its task simultaneously. Main areas of recent research in …


Observation Of The Plasma Channel Dynamics And Coulomb Explosion In The Interaction Of A High-Intensity Laser Pulse With A He Gas Jet, G.S. Sarkisov, V. Yu. Bychenkov, V.T. Tikhonchuk, Anatoly Maksimchuk, Shouyuan Chen, R. Wagner, G. Mourou, Donald P. Umstadter Dec 1997

Observation Of The Plasma Channel Dynamics And Coulomb Explosion In The Interaction Of A High-Intensity Laser Pulse With A He Gas Jet, G.S. Sarkisov, V. Yu. Bychenkov, V.T. Tikhonchuk, Anatoly Maksimchuk, Shouyuan Chen, R. Wagner, G. Mourou, Donald P. Umstadter

Donald Umstadter Publications

We report the first interferometric observations of the dynamics of electron–ion cavitation of relativistically self-focused intense 4 TW, 400 fs laser pulse in a He gas jet. The electron density in a channel 1 mm long and 30 mm in diameter drops by a factor of approximately 10 from the maximum value of ~8x1019 cm23. A high radial velocity of the plasma expansion, ~3.8x108 cm/s, corresponding to an ion energy of about 300 keV, is observed. The total energy of fast ions is estimated to be 6% of the laser pulse energy. The high-velocity radial plasma …


On The Strain-Rate Sensitivity Of Columnar Ice, M. E. Manley, E. M. Schulson Dec 1997

On The Strain-Rate Sensitivity Of Columnar Ice, M. E. Manley, E. M. Schulson

Dartmouth Scholarship

A power law relation between stress and strain rate of the form σ ∝ ε̇1/n was used to describe the response to strain rate of S1 ice loaded across the columns at -10°C. The rate exponent, n, decreased with increasing strain from about 4.6 at an observed peak on the load displacement curve to approximately 2.6 at a shortening of 2%. Analysis of these results and of the results of other authors on different forms of ice deformed at the same temperature suggests that the power law exponent, n, is proportional to Fc/Fg. The parameter Fc/Fg is the far-field basal …


Some Problems In Estimating Finite Population Total And Variance In Survey Sampling., Saswati Bhattacharya Dr. Dec 1997

Some Problems In Estimating Finite Population Total And Variance In Survey Sampling., Saswati Bhattacharya Dr.

Doctoral Theses

The problem of drawing inference concerning the parameters of a finite population of identifiable units has been increasingly engaging the attention of statisticians. The central problem here is to devise a suitable method of selecting a sample from the population and to employ an appropriate estimator to estimate the finite population total or mean. A consider- able progress in this field of study has been made and many authors have contributed towards the development of the theory in this aspect of the problem of statistical inferenceNumerous papers have been written covering the first aspect of the problem, namely, method of …


Distributions Of Beryllium 7 And Lead 2109, And Soluble Aerosol-Associated Ionic Species Over The Western Pacific: Pem West B, February-March 1994, Jack E. Dibb, R. Talbot, Barry Lefer, Eric Scheuer, G L. Gregory, E V. Browell, J D. Bradshaw, S T. Sandholm, H B. Singh Dec 1997

Distributions Of Beryllium 7 And Lead 2109, And Soluble Aerosol-Associated Ionic Species Over The Western Pacific: Pem West B, February-March 1994, Jack E. Dibb, R. Talbot, Barry Lefer, Eric Scheuer, G L. Gregory, E V. Browell, J D. Bradshaw, S T. Sandholm, H B. Singh

Earth Sciences

Aerosol sampling for the determination of the concentrations of soluble ionic species and the natural radionuclides 7Be and 210Pb was conducted from the NASA DC-8 over the western Pacific as part of GTE/PEM-West B during February-March 1994. Concentrations of most soluble ionic species in the free troposphere were higher in samples collected on flights originating from Hong Kong and Japan than those collected further east over the open ocean. In both regions the measured concentrations were higher than those found during PEM-West A (fall 1991). Activities of 210Pb, a tracer of air masses influenced by sources on …


Comparisons Of Trace Constituents From Ground Stations And The Dc-8 Aircraft During Pem-West B, Richard Arimoto, R A. Duce, J M. Prospero, D L. Savoie, R. Talbot, Jack E. Dibb, B J. Heikes, B J. Ray, N F. Lewis, U Tomza Dec 1997

Comparisons Of Trace Constituents From Ground Stations And The Dc-8 Aircraft During Pem-West B, Richard Arimoto, R A. Duce, J M. Prospero, D L. Savoie, R. Talbot, Jack E. Dibb, B J. Heikes, B J. Ray, N F. Lewis, U Tomza

Earth Sciences

Chemical data from ground stations in Asia and the North Pacific are compared with data from the DC-8 aircraft collected during the Pacific Exploratory Measurements in the Western Pacific Ocean (PEM-West B) mission. Ground station sampling took place on Hong Kong, Taiwan, Okinawa, and Cheju; and at three Pacific islands, Shemya, Midway, and Oahu. Aircraft samples were collected during 19 flights, most over the western North Pacific. Aluminum was used as an indicator of mineral aerosol, and even though the aircraft did sample Asian dust, strong dust storms were not encountered. The frequency distribution for non-sea-salt sulfate (nss SO4 …


Transport Of Sulfur Dioxide From The Asian Pacific Rim To The North Pacific Troposphere, D C. Thornton, A R. Bandy, Byrin W. Blomquist, R. Talbot, Jack E. Dibb Dec 1997

Transport Of Sulfur Dioxide From The Asian Pacific Rim To The North Pacific Troposphere, D C. Thornton, A R. Bandy, Byrin W. Blomquist, R. Talbot, Jack E. Dibb

Earth Sciences

The NASA Pacific Exploratory Mission over the Western Pacific Ocean (PEM-West B) field experiment provided an opportunity to study sulfur dioxide (SO2) in the troposphere over the western Pacific Ocean from the tropics to 60°N during February–March 1993. The large suite of chemical and physical measurements yielded a complex matrix in which to understand the distribution of sulfur dioxide over the western Pacific region. In contrast to the late summer period of Pacific Exploratory Mission-West A (PEM-West A) (1991) over this same area, SO2showed little increase with altitude, and concentrations were much lower in the free …


Chemical Characteristics Of Continental Outflow From Asia To The Troposphere Over The Western Pacific Ocean During February-March 1994: Results From Pem-West B, R. Talbot, Jack E. Dibb, Barry Lefer, J D. Bradshaw, S T. Sandholm, D R. Blake, N J. Blake, G W. Sachse, J E. Collins Jr, B J. Heikes, J T. Merrill, G L. Gregory, B E. Anderson, H B. Singh, D C. Thornton, A R. Bandy, R F. Pueschel Dec 1997

Chemical Characteristics Of Continental Outflow From Asia To The Troposphere Over The Western Pacific Ocean During February-March 1994: Results From Pem-West B, R. Talbot, Jack E. Dibb, Barry Lefer, J D. Bradshaw, S T. Sandholm, D R. Blake, N J. Blake, G W. Sachse, J E. Collins Jr, B J. Heikes, J T. Merrill, G L. Gregory, B E. Anderson, H B. Singh, D C. Thornton, A R. Bandy, R F. Pueschel

Earth Sciences

We present here the chemical composition of outflow from the Asian continent to the atmosphere over the western Pacific basin during the Pacific Exploratory Mission-West (PEM-West B) in February–March 1994. Comprehensive measurements of important tropospheric trace gases and aerosol particulate matter were performed from the NASA DC-8 airborne laboratory. Backward 5 day isentropic trajectories were used to partition the outflow from two major source regions: continental north (>20°N) and continental south (<20°N). Air parcels that had not passed over continental areas for the previous 5 days were classified as originating from an aged marine source. The trajectories and the chemistry together indicated that there was extensive rapid outflow of air parcels at altitudes below 5 km, while aged marine air was rarely encountered and only at <20°N latitude. The outflow at low altitudes had enhancements in common industrial solvent vapors such as C2Cl4, CH3CCl3, and C6H6, intermixed with the combustion emission products C2H2, C …


Large-Scale Distributions Of Tropospheric Nitric, Formic, And Acetic Acids Over The Western Pacific Basin During Wintertime, R. Talbot, Jack E. Dibb, Barry Lefer, Eric Scheuer, J D. Bradshaw, S T. Sandholm, S Smyth, D R. Blake, N J. Blake, G W. Sachse, J E. Collins Jr, G L. Gregory Dec 1997

Large-Scale Distributions Of Tropospheric Nitric, Formic, And Acetic Acids Over The Western Pacific Basin During Wintertime, R. Talbot, Jack E. Dibb, Barry Lefer, Eric Scheuer, J D. Bradshaw, S T. Sandholm, S Smyth, D R. Blake, N J. Blake, G W. Sachse, J E. Collins Jr, G L. Gregory

Earth Sciences

We report here measurements of the acidic gases nitric (HNO3), formic (HCOOH), and acetic (CH3COOH) over the western Pacific basin during the February-March 1994 Pacific Exploratory Mission-West (PEM-West B). These data were obtained aboard the NASA DC-8 research aircraft as it flew missions in the altitude range of 0.3–12.5 km over equatorial regions near Guam and then further westward encompassing the entire Pacific Rim arc. Aged marine air over the equatorial Pacific generally exhibited mixing ratios of acidic gases <100 parts per trillion by volume (pptv). Near the Asian continent, discrete plumes encountered below 6 km altitude contained up to 8 parts per billion by volume (ppbv) HNO3 and 10 ppbv HCOOH and CH3COOH. Overall there was a general correlation between mixing …


A Detailed Comparison Of Hubble Space Telescopefaint Object Spectrograph Andiueultraviolet Spectra Of Selected Seyfert Nuclei, Anuradha Koratkar, Ian Evans, Sharon Pesto, Cynthia Taylor Dec 1997

A Detailed Comparison Of Hubble Space Telescopefaint Object Spectrograph Andiueultraviolet Spectra Of Selected Seyfert Nuclei, Anuradha Koratkar, Ian Evans, Sharon Pesto, Cynthia Taylor

Dartmouth Scholarship

Despite the contributions of the Hubble Space Telescope Faint Object Spectrograph (FOS) to the archive of UV observations of active galactic nuclei, the vast majority of UV reference data were obtained using the International Ultraviolet Explorer (IUE) satellite. These data remain important since they provide historical information about the intensities of the UV continua and emission lines that is needed to constrain models of the active nucleus. A detailed comparison of the FOS and IUE data is critical to understanding how the measurable quantities depend on the individual instrumental calibrations, and how any conclusions derived from modeling the …


Concept Vectors: A Synthesis Of Concept Mapping And Matrices For Knowledge Representation In Intelligent Tutoring Systems, Mark L. Dyson Dec 1997

Concept Vectors: A Synthesis Of Concept Mapping And Matrices For Knowledge Representation In Intelligent Tutoring Systems, Mark L. Dyson

Theses and Dissertations

A review of the literature relating to intelligent tutoring systems (ITS) reveals that the bulk of research to date is focused on the student, and on methods for representing the knowledge itself. From student models to learning schemas to presentation methods, comparatively little attention has been paid to the problem of educators attempting to build viable lesson plans for use in an ITS environment--yet when this problem is addressed in the literature, it is recognized as a potentially daunting one. This thesis addresses the problem of ITS lesson plan development by proposing a practical, computable approach for knowledge engineering that …


A New Approach To Probing Large-Scale Power With Peculiar Velocities, Hume A. Feldman, Richard Watkins Dec 1997

A New Approach To Probing Large-Scale Power With Peculiar Velocities, Hume A. Feldman, Richard Watkins

Dartmouth Scholarship

We propose a new strategy for probing the power spectrum on large scales using galaxy peculiar velocities. We explore the properties of surveys that cover only two small fields in opposing directions on the sky. Surveys of this type have several advantages over those that attempt to cover the entire sky; in particular, by concentrating on galaxies in narrow cones, these surveys are able to achieve the density needed to measure several moments of the velocity field with only a modest number of objects, even for surveys designed to probe scales >∼100h−1Mpc. We construct mock surveys with this …


Global Energetic Neutral Atom (Ena) Measurements And Their Association With The Dst Index, A. M. Jorgensen, Harlan E. Spence, M. G. Henderson, G. D. Reeves, M. Sugiura, T. Kamei Dec 1997

Global Energetic Neutral Atom (Ena) Measurements And Their Association With The Dst Index, A. M. Jorgensen, Harlan E. Spence, M. G. Henderson, G. D. Reeves, M. Sugiura, T. Kamei

Physics & Astronomy

We present a new global magnetospheric index that measures the intensity of the Earth's ring current through energetic neutral atoms (ENAs). We have named it the Global Energetic Neutral Index (GENI), and it is derived from ENA measurements obtained by the Imaging Proton Spectrometer (IPS), part of the Comprehensive Energetic Particle and Pitch Angle Distribution (CEPPAD) experiment on the POLAR satellite. GENI provides a simple orbit-independent global sum of ENAs measured with IPS. Actual ENA measurements for the same magnetospheric state look different when seen from different points in the POLAR orbit. In addition, the instrument is sensitive …


Dimethyl (±)-(1s*,2r*,3s*)-[3-Phenyl-1-(N-Phenylcarbamoyloxy)-2, 3-Epoxypropyl]-Phosphonate, T. Boehlow, A. De La Cruz, N. Rath, C. Spilling Dec 1997

Dimethyl (±)-(1s*,2r*,3s*)-[3-Phenyl-1-(N-Phenylcarbamoyloxy)-2, 3-Epoxypropyl]-Phosphonate, T. Boehlow, A. De La Cruz, N. Rath, C. Spilling

Chemistry & Biochemistry Faculty Works

The crystal structure of the racemic title compound, C18H20NO6P, m.p. 428-431 K, has been determined by X-ray diffraction. The title compound consists of a tetrahedral P atom bonded to two methoxy groups, and an alkyl chain. The alkyl chain was substituted at position 1 with a carbamate and with an epoxide at positions 2 and 3. The relative configuration of the 1-carbamate and 2,3-epoxide substituents was confirmed as anti (1S,2R,3S). The crystal structure contains an enantiomeric pair with two intermolecular hydrogen bonds in a 14-membered ring. The hydrogen bonds are formed between the P=O of one enantiomer and the N-H …


Nanoscale Imaging Of Domain Dynamics And Retention In Ferroelectric Thin Films, Alexei Gruverman, H. Tokumoto, A. S. Prakash, S. Aggarwal, B. Yang, M. Wuttig, R. Ramesh, O. Auciello, T. Venkatesan Dec 1997

Nanoscale Imaging Of Domain Dynamics And Retention In Ferroelectric Thin Films, Alexei Gruverman, H. Tokumoto, A. S. Prakash, S. Aggarwal, B. Yang, M. Wuttig, R. Ramesh, O. Auciello, T. Venkatesan

Alexei Gruverman Publications

We report results on the direct observation of the microscopic origins of backswitching in ferroelectric thin films. The piezoelectric response generated in the film by a biased atomic force microscope tip was used to obtain static and dynamic piezoelectric images of individual grains in a polycrystalline material. We demonstrate that polarization reversal occurs under no external field (i.e., loss of remanent polarization) via a dispersive continuous-time random walk process, identified by a stretched exponential decay of the remanent polarization.


Electro-Deposition Of Polymer Chains On An Adsorbing Wall: Density Profiles And Wall Coverage, Grace M. Foo, Ras B. Pandey Dec 1997

Electro-Deposition Of Polymer Chains On An Adsorbing Wall: Density Profiles And Wall Coverage, Grace M. Foo, Ras B. Pandey

Faculty Publications

Growth of polymer density in an electro-deposition model of polymer chains on an impenetrable wall is studied on a two dimensional discrete lattice using a Monte Carlo simulation. Polymer-polymer repulsion and polymer-wall attraction for the adsorbing wall (along with the neutral and repulsive interactions) are considered in an external field. Effects of the field strength (B), temperature (T), and chain length (L-c) on the density profile of the polymer chains and wall coverage are investigated. The spatial density profile shows onset of oscillation near the wall at a characteristic field (B-c) which depends on chain length and temperature, In low …


Measurement Of The Focal Properties Of A Magnetic Electron Lens Using The Shadowgraph Method, Luis Thomas Almaraz Dec 1997

Measurement Of The Focal Properties Of A Magnetic Electron Lens Using The Shadowgraph Method, Luis Thomas Almaraz

Dissertations and Theses

A method of experimentally determining the properties of a magnetic electron lens is presented. The method uses the shadows cast by two meshes, one placed in front of the lens and one behind the lens, to study the properties of the image of a point source. The lens properties are then calculated from the image properties. The paraxial values of focal length and focal distance as well as their spherical aberrations, are determined. The relationship between image and lens properties are discussed. The method is used here for the first time in determining the focal properties of a magnetic lens.


The Temperature Dependent Modification Of The Ca2+ Release Mechanism Of Skeletal Muscle Sarcoplasmic Reticulum, Shawn Patrick Mullen Dec 1997

The Temperature Dependent Modification Of The Ca2+ Release Mechanism Of Skeletal Muscle Sarcoplasmic Reticulum, Shawn Patrick Mullen

Dissertations and Theses

The Ca2+ release protein/ryanodine receptor from skeletal muscle sarcoplasmic reticulum is shown to be modulated in a unique manner by small changes in temperature. Thiol oxidants and reducing agents modify channel function in a biphasic manner at 40° C, while at 34° C the channel exhibits only a monophasic behavior. Elevated temperature appears to expose a second set of reactive groups that, when either oxidized or reduced, alter function. Previous studies have focused on the properties of the release mechanism at or below 37° C. This study shows that at 40° C, which more reflects the body temperature of …


Hyperfine Splitting Of Low-Lying Heavy Baryons, Joseph Schechter, Masayasu Harada, Asif Qamar, Francesco Sannino, Herbert Weigel Dec 1997

Hyperfine Splitting Of Low-Lying Heavy Baryons, Joseph Schechter, Masayasu Harada, Asif Qamar, Francesco Sannino, Herbert Weigel

Physics - All Scholarship

We calculate the next-to-leading order contribution to the masses of the heavy baryons in the bound state approach for baryons containing a heavy quark. These 1/N_C corrections arise when states of good spin and isospin are generated from the background soliton of the light meson fields. Our study is motivated by the previously established result that light vector meson fields are required for this soliton in order to reasonably describe the spectrum of both the light and the heavy baryons. We note that the inclusion of light vector mesons significantly improves the agreement of the predicted hyperfine splitting with experiment. …


A Palynological Study Of Two Upland Bogs In The Gulf Coastal Plain, Alabama And Mississippi, Linda C. Pace Dec 1997

A Palynological Study Of Two Upland Bogs In The Gulf Coastal Plain, Alabama And Mississippi, Linda C. Pace

LSU Historical Dissertations and Theses

Fewer Quaternary palynological studies have been conducted in the Gulf Coastal Plain of the southeastern United States than In the northern United States and Canada, resulting in major gaps in the pollen record of this region. The existing studies display discrepancies in the chronology of the pine rise, appearance of the modem climatic regime and vegetation, and timing of the Hypsithermal. In order to fill a gap in the paleoecological data network of the Gulf Coastal Plain, pollen analysis, charcoal analysis, and sediment stratigraphic techniques were used to reconstruct the last 6500 years of Sweetbay Bog, Mississippi, and Minamac Bog, …


Learning To See Analogies: A Connectionist Exploration, Douglas S. Blank Dec 1997

Learning To See Analogies: A Connectionist Exploration, Douglas S. Blank

Computer Science Faculty Research and Scholarship

The goal of this dissertation is to integrate learning and analogy-making. Although learning and analogy-making both have long histories as active areas of research in cognitive science, not enough attention has been given to the ways in which they may interact. To that end, this project focuses on developing a computer program, called Analogator, that learns to make analogies by seeing examples of many different analogy problems and their solutions. That is, it learns to make analogies by analogy. This approach stands in contrast to most existing computational models of analogy in which particular analogical mechanisms are assumed a priori …


Audit Of The Department Of Energy's Contracts With Envirocare Of Utah, Inc., U.S. Department Of Energy, Office Of Inspector General, Office Of Audit Services, Eastern Regional Audit Office Dec 1997

Audit Of The Department Of Energy's Contracts With Envirocare Of Utah, Inc., U.S. Department Of Energy, Office Of Inspector General, Office Of Audit Services, Eastern Regional Audit Office

All U.S. Government Documents (Utah Regional Depository)

The Department of Energy (Department) is responsible for protecting human health and the environment by providing an effective and efficient system that treats, stores, and disposes of Departmental waste. The Department disposes of some of its waste at Envirocare of Utah, Inc., (Envirocare) a commercial treatment and disposal facility in Clive, Utah. The audit objective was to determine whether the Department and its contractors were using the most favorable rates available for the disposal of waste at Envirocare.

We found that the Department's contractors did not always use the most favorable rates available. Although volume discounts were available under Departmentwide …


Effective Elastic Thickness Of The Lithosphere Along The Easter Seamount Chain, Sarah E. Kruse, Zhengro J. Liu, David F. Naar, Robert A. Duncan Dec 1997

Effective Elastic Thickness Of The Lithosphere Along The Easter Seamount Chain, Sarah E. Kruse, Zhengro J. Liu, David F. Naar, Robert A. Duncan

Geology Faculty Publications

Bathymetry and gravity data collected during Legs 5, 6, and 7 of the 1993 GLORIA Expedition and the recently released 2-min altimetry-derived global gravity grid are used to determine the effective elastic thickness of the lithosphere along the Easter Seamount Chain (ESC). Forward modeling, admittance, and coherence methods yield consistent results. With the exception of the eastern and western ends of the ESC the effective elastic thickness along the chain is ∼1–4 km. The thin elastic thickness for the majority of the ESC seamounts is compatible with a young seafloor age at the time of loading derived from new radiometric …


Bias And The Probability Of Generalization, Tony R. Martinez, D. Randall Wilson Dec 1997

Bias And The Probability Of Generalization, Tony R. Martinez, D. Randall Wilson

Faculty Publications

In order to be useful, a learning algorithm must be able to generalize well when faced with inputs not previously presented to the system. A bias is necessary for any generalization, and as shown by several researchers in recent years, no bias can lead to strictly better generalization than any other when summed over all possible functions or applications. This paper provides examples to illustrate this fact, but also explains how a bias or learning algorithm can be “better” than another in practice when the probability of the occurrence of functions is taken into account. It shows how domain knowledge …


Phase Structure Of Dynamical Triangulation Models In Three Dimensions, Simon Catterall, Ray L. Renken, John B. Kogut Dec 1997

Phase Structure Of Dynamical Triangulation Models In Three Dimensions, Simon Catterall, Ray L. Renken, John B. Kogut

Physics - All Scholarship

The dynamical triangulation model of three-dimensional quantum gravity is shown to have a line of transitions in an expanded phase diagram which includes a coupling mu to the order of the vertices. Monte Carlo renormalization group and finite size scaling techniques are used to locate and characterize this line. Our results indicate that for mu < mu1 ~ -1.0 the model is always in a crumpled phase independent of the value of the curvature coupling. For mu < 0 the results are in agreement with an approximate mean field treatment. We find evidence that this line corresponds to first order transitions extending to positive mu. However, the behavior appears to change for mu > mu2 ~ 2-4. The simplest scenario that is consistent with the data is the existence of a critical end point.


Stern-Gerlach Effect For Electron Beams, Herman Batelaan, Timothy J. Gay, J. J. Schwendiman Dec 1997

Stern-Gerlach Effect For Electron Beams, Herman Batelaan, Timothy J. Gay, J. J. Schwendiman

Timothy J. Gay Publications

The conflict between Bohr’s assertion that the magnetic moment of the electron cannot be measured with experiments based on the concept of classical trajectories, and the measurement of the magnetic moment of electrons in a modified Penning trap by Dehmelt et al. has led us to reevaluate other implications of Bohr’s assertion. We show that, contrary to the analysis of Bohr and Pauli, the assumption of classical trajectories in a Stern-Gerlach–like device can result in a high degree of spin separation for an electron beam. This effect may persist within a fully quantum-mechanical analysis. The magnetic fields considered are such …


Probing The Intermolecular Hydrogen Bonding Of Water Molecules At The Ccl4/Water Interface In The Presence Of Charges Soluble Surfactant, D. E. Gragson, G. L. Richmond Dec 1997

Probing The Intermolecular Hydrogen Bonding Of Water Molecules At The Ccl4/Water Interface In The Presence Of Charges Soluble Surfactant, D. E. Gragson, G. L. Richmond

Chemistry and Biochemistry

The molecular structure and hydrogen bonding of water molecules at the CCl4/water interface in the presence of a charged soluble surfactant has been explored in this study using vibrational sum frequency generation. By examining OH stretching modes that are highly sensitive to the local hydrogen bonding environment it is found that water molecules at the CCl4/water interface both in the presence and absence of a charged soluble surfactant are predominantly in a tetrahedral arrangement much like the structure ofice. Isotopic dilution studies have been employed to further characterize this icelike interfacial structure. Ablueshift ofapproximately120 cm-1 …