Physical Sciences and Mathematics Commons^™

Optically Induced Periodic Structures In Smectic-C Liquid Crystals, Antal Jákli, A. Vajda, E. Benkler, Janossy, Peter Palffy-Muhoray

Antal Jakli

We explore periodic structures of smectic-C (SmC) liquid crystals, induced optically by a polarization grating. The studied cells contain a passive surface of rubbed polyimide and an active photosensitive substrate of ate-dye doped polyimide. In a nematic phase the director field can be periodic independent of the angle between the grating vector and the rubbing direction. In the SmA phase periodic structure can be induced only by layer undulations. The SmC behaves similarly to the nematic phase, but the director can rotate only on a cone, which results in a more complex geometry. The periodic pattern is superimposed with four …

Covert Shells, John Christian Smith

John Christian Smith

The potential for covert communications exist anywhere that legitimate communication channels are in use. In order to maintain control of the channel once exploited, the insertion of a backdoor Trojan horse server, to be used with a client that provides shell access, is often a necessary prerequisite to establishing and using a covert channel long term.

We discuss covert channel communications methods ranging from embedded channels to disguised protocols. What follows is a review of available covert shell tools. The underground, historical evolution of covert shells is reviewed, focusing on selected, available tools, which range from simple encapsulation methods to …

Resonance Line Scattering Polarization In Optically Thin Planar Equatorial Disks., Richard Ignace

Richard Ignace

This paper is the third in a series on the anisotropic scattering by optically thin resonance lines in extended stellar envelopes. Considered here is the polarization arising from resonance line scattering in equatorial disks. The shape of the polarized line profile is analytically derived under simplifying conditions of constant expansion or rotation for thin lines, with stellar occultation and finite star depolarization effects also included. The polarized profiles for the two cases are radically different. Moreover owing to the symmetries, rotation leads to profiles in both Q_ν and U_ν, whereas only a Q_ν profile survives for …

Clustering Irregular Shapes Using High-Order Neurons, H. Lipson, Hava Siegelmann

Hava Siegelmann

This article introduces a method for clustering irregularly shaped data arrangements using high-order neurons. Complex analytical shapes are modeled by replacing the classic synaptic weight of the neuron by high-order tensors in homogeneous coordinates. In the first- and second-order cases, this neuron corresponds to a classic neuron and to an ellipsoidalmetric neuron. We show how high-order shapes can be formulated to follow the maximum-correlation activation principle and permit simple local Hebbian learning. We also demonstrate decomposition of spatial arrangements of data clusters, including very close and partially overlapping clusters, which are difficult to distinguish using classic neurons. Superior results are …

Exospheric Models For The X-Ray Emission From Single Wolf-Rayet Stars., R. Ignace, L. M. Oskinova

Richard Ignace

We review existing ROSAT detections of single Galactic Wolf-Rayet (WR) stars and develop wind models to interpret the X-ray emission. The ROSAT data, consisting of bandpass detections from the ROSAT All-Sky Survey (RASS) and some pointed observations, exhibit no correlations of the WR X-ray luminosity (L_X) with any star or wind parameters of interest (e.g. bolometric luminosity, mass-loss rate or wind kinetic energy), although the dispersion in the measurements is quite large. The lack of correlation between X-ray luminosity and wind parameters among the WR stars is unlike that of their progenitors, the O stars, which show …

Bezpośrednie I Pośrednie Efekty Wprowadzenia Ciągłego Odlewania Stali W Bilansie Emisji Zanieczyszczeń Z Huty Żelaza, Marian Mazur, Marek Bogacki, Robert Oleniacz

Robert Oleniacz

This paper presents a comprehensive analysis of the impact of continuous casting technology on emissions of air pollutants from "Katowice" Steelworks in Dąbrowa Górnicza (Poland). Sources of emissions occurring in the manufacturing process and emissions levels have been identified. Implementation of continuous casting of steel has increased the efficiency of production and brought substantial ecological effects.

English title: Direct and indirect effects of introduction of continuous casting of steel in the balance sheet of pollutant emissions from "Katowice" Steelworks.

An Autonomous Water Vapor Plume Tracking Robot Using Passive Resistive Polymer Sensors, S. Kazadi, R. Goodman, D. Tsikata, D. Green, H. Lin

Sanza Kazadi

A Support Vector Method For Clustering, Asa Ben-Hur, David Horn, Hava Siegelmann, Vladimir Vapnik

Hava Siegelmann

We present a novel method for clustering using the support vector machine approach. Data points are mapped to a high dimensional feature space, where support vectors are used to define a sphere enclosing them. The boundary of the sphere forms in data space a set of closed contours containing the data. Data points enclosed by each contour are defined as a cluster. As the width parameter of the Gaussian kernel is decreased, these contours fit the data more tightly and splitting of contours occurs. The algorithm works by separating clusters according to valleys in the underlying probability distribution, and thus …

Relaxation Dynamics Of Rubbed Polystyrene Thin Films, D. M. G. Agra, A. D. Schwab, J-H. Kim, Satyendra Kumar, A. Dhinojwala

Satyendra Kumar

Optical retardation measurements were used to probe the chain relaxation dynamics in rubbed polystyrene films of varying thicknesses on glass substrates. A model based on Kohlrausch-Williams-Watts relaxation was developed and used to determine the glass transition temperature (Tg) of the films. Results showed reductions of 15–20 K in Tg for thin films of thicknesses comparable to the radius of gyration as well as for cast films rubbed with different strengths. These results provide evidence of a faster relaxation dynamics relative to the polymer-substrate interface for thinner films and enhanced chain mobility at the polymer-air interface.

Measurements Of The Hyperpolarizability Tensor By Means Of Hyper-Rayleigh Scattering, Liang-Chy Chien, V. Ostroverkhova, R. G. Petschek, K. D. Singer, L. Sukhomlinova, R. J. Twieg, S.-X. Wang

Liang-Chy Chien

We describe improvements to a previously reported hyper-Rayleigh scattering technique [J. Opt. Sec. Am. B 15, 289 (1998)], for measuring all rotational invariants of the first hyperpolarizability tensor. The full hyper-Rayleigh scattering tensor is expressed in terms of its rotationally invariant components leading to a figures of merit corresponding to each of the rotationally invariant tensors. With elliptically polarized incident light, the polarization state and the intensity of the harmonic light are measured at a scattering angle of 45 degrees. A new analytical fitting method is applied to the signal for two polarization measurements to yield the invariants. We have …

Is Overexcitability A Differential Personality Attribute Of High-Iq Youth? A Comparison Study Of Identified Gifted And Vocational High School Teenagers Using The Overexcitability Questionnaire (Oeq), Jane Piirto, Lori Beach, Geri Cassone, Robbin Rogers, John Fraas

John W. Fraas

No abstract provided.

On The Effect Of Long-Wavelength Electron Plasma Waves On Large-Angle Stimulated Raman Scattering Of Short Laser Pulse In Plasmas, Nikolai E. Andreev, Serguei Y. Kalmykov

Serge Youri Kalmykov

Spectral features of a large-angle stimulated Raman scattering (LA SRS) of a short electromagnetic pulse in an underdense plasma, which are caused by the presence in a plasma of a given linear long-wavelength electron plasma wave (LW EPW), are investigated. It is shown that the LW EPW, whose phase velocity coincides with a group velocity of a pulse and a density perturbation normalized to a background electron density, \delta n_{LW} / n_0, exceeds the ratio of the electron plasma frequency to the laser frequency, \omega_{pe} / \omega_0, suppresses the well-known Stokes branch of the weakly coupled LA SRS. Under the …

Analytic Inversion Of Emission Lines Of Arbitrary Optical Depth For The Structure Of Supernova Ejecta., R. Ignace, M. A. Hendry

Richard Ignace

We derive a method for inverting emission line profiles formed in supernova ejecta. The derivation assumes spherical symmetry and homologous expansion (i.e., v(r)∝r), is analytic, and even takes account of occultation by a pseudo-photosphere. Previous inversion methods have been developed which are restricted to optically thin lines, but the particular case of homologous expansion permits an analytic result for lines of arbitrary optical depth. In fact, we show that the quantity that is generically retrieved is the run of line intensity Iλ with radius in the ejecta. This result is quite general, and so could be applied to resonance lines, …

The Complexity Of Decentralized Control Of Markov Decision Processes, Daniel S. Bernstein, Shlolo Zilberstein, Neil Immerman

Neil Immerman

Planning for distributed agents with partial state information is considered from a decisiontheoretic perspective. We describe generalizations of both the MDP and POMDP models that allow for decentralized control. For even a small number of agents, the finite-horizon problems corresponding to both of our models are complete for nondeterministic exponential time. These complexity results illustrate a fundamental difference between centralized and decentralized control of Markov processes. In contrast to the MDP and POMDP problems, the problems we consider provably do not admit polynomialtime algorithms and most likely require doubly exponential time to solve in the worst case. We have thus …

Time Domain Probabilistic Risk Assessment:, George H. Baker, Charles T. C. Mo

George H Baker

For critical facilities, survivability and reconstitution in stressful environments generated by electromagnetic transients, sabotage, terrorist activity, military conflict, or Murphy’s laws are issues of concern. Critical fixed facilities are likely to be functionally complex and their system-wide failure probabilities, modes, and consequences are often not obvious. To analyze and quantify survivability, existing probabilistic risk assessment tools usually provide a “snapshot” of failure modes at a single point of time for certain initiating conditions. Likewise, elaborate physics models developed to treat weapons effects on structures and individual functional components compute effects at a single time point.

We have developed a tool …

Hot Star Polarimetric Variability And The Nature Of Wind Inhomogeneities., J. C. Brown, R. Ignace, J. P. Cassinelli

Richard Ignace

The problem is addressed of how much hot star polarisation variability can result from density redistribution processes within the wind as opposed to localised enhancement of stellar mass loss rate, such as ejections of wind inhomogeneities. For optically thin electron scattering, we present a theory for the relative polarisation arising from particle redistribution and consider several specific cases relevant to interpreting observations of wind variability. It is concluded that, allowing for partial cancellation of the contribution from compressed and evacuated regions, density redistribution internal to the wind can produce significant polarisation but only for processes that redistribute wind material over …

Correction Of Seismic Amplitude Maps To Validate Amplitude Derived Porosity Inferences., Thomas M. Loretto

Thomas M Loretto

No abstract provided.

The Vaporization Enthalpies Of Some Crown And Polyethers By Correlation Gas Chromatography, Gary Nichols, Jennifer Orf, Sarah M. Reiter, James Chickos, George W. Gokel

James Chickos

No abstract provided.

Mind-Matter Interaction In Quantum Physics, Milan Meszaros Physicist

Milan Meszaros physicist

By the end of the 20th century, the Einstein-Podolsky-Rosen, Schrödinger’s cat and Wigner’s friend paradoxes of quantum theory were already known. The Bell’s inequalities, the Aharonov-Bohm effect and the holographical principles etc. were also acquainted. There were positive experiments of Aspect, Daligbard and Roger just as Aspect, Grangier and Roger etc. In connection with these paradoxes and paradoxical experiments etc., the questions are raised: What is the ontological frame for description of these effects or notions: nonlocal, guiding wave (pilot wave), instantenous, delayed-choice experiments, superluminal, ghost wave, immaterial or mind, mind-matter interaction, holographical universe or entangled states just as quantum …

Spectral Function Of Composites From Reflectivity Measurements, Anthony Day, A. Grant, A. Sievers, M. Thorpe

Anthony Roy Day

We demonstrate a method of calculating the spectral function of a composite from measured reflectivity data. To solve this inverse problem it is necessary for the reflectivity data to be taken through a strong, high Q, resonance. By analyzing the reststrahlen region of different fill fraction KCl-diamond composites at three different temperatures, we find accurate spectral functions that are independent of temperature with the low temperature data giving the best resolution. These spectral functions are then used to successfully predict the optical response of RbCl-diamond composites.

The Phillips Properties, Walden Freedman, Ali Ülger

Walden Freedman

A Banach space  has the Phillips property if the canonical projection  is sequentially weak-norm continuous, and has the weak Phillips property if  is sequentially weak-weak continuous. We study both properties in connection with other geometric properties, such as the Dunford-Pettis property, Pelczynski's properties  and (V), and the Schur property.

Mirage Mirror On The Wall, T. Kosa, Peter Palffy-Muhoray

Peter Palffy-Muhoray

We discuss mirages formed near a sun-heated wall, and consider the underlying physics. The temperature and refractive index variations in air near the wall are estimated, and a simple approximate picture of ray propagation is presented. Estimates of the thermal decay length and ray curvature are compared with experimental observations.

Rapid Solidification: Fundamentals And Modeling, Guo-Xiang Wang, Vish Prasad

Dr. Guo-Xiang Wang

No abstract provided.

Automatic Segmentation And Indexing In A Database Of Bird Images, Madirakshi Das, R. Manmatha

R. Manmatha

The aim of this work is to index images in domain specific databases using colors computed from the object of interest only, instead of the whole image. The main problem in this task is the segmentation of the region of interest from the background. Viewing segmentation as a figure/ground segregation problem leads to a new approach - eliminating the background leaves the figure or object of interest. To find possible object colors, we first find background colors and eliminate them. We then use an edge image at an appropriate scale to eliminate those parts of the image which are not …

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

Tian-Xiao He

No abstract provided.

Systems Of Difference Equations With Asymptotically Constant Solutions, William F. Trench

William F. Trench

No abstract provided.

New Isotopic Evidence For Chronic Lead Contamination In The San Francisco Bay Estuary System: Implications For The Persistence Of Past Industrial Lead Emissions In The Biosphere, Douglas J. Steding, Charles E. Dunlap, A. Russell Flegal

Charles Dunlap

Measurements of lead isotope compositions in unfiltered San Francisco Bay waters from 1989 to 1998 have brought new insights into the cycling of anthropogenic lead in estuaries. Isotopic com- positions of lead in the shallow (<2 m) southern reach were essentially invariant (~90% derived from 1960s–1970s leaded gasoline) during the study period because of limited hydraulic flushing and the remobilization of lead from bottom sediments. In contrast, in the northern reach freshwater flushing from the San Joaquin and Sacramento rivers produced seasonal and decadal variations in lead isotope compositions. The seasonal shifts are attributed to advection of soils containing late 1980s gasoline lead into the bay during winter rains. Mass balance calculations indicate that only a small fraction (1–10%) of this leaded gasoline fallout from the late 1980s has been washed out of the San Joaquin and Sacramento rivers’ drainage basin by 1995. Superimposed on this seasonal cycling was a long-term systematic shift in the component of gasoline lead expressed in the river systems, with a small (~5–10%) decrease in the amount of 1960s–1970s gasoline lead in river and North Bay waters. The retention of gasoline lead in the river systems draining into the bay as well as San Francisco Bay sediments indicates that historic gasoline deposits may remain in the combined riparian/estuarine system for decades. Such a persistence is in contraindication to recent reports of rapid (annual) decreases in lead contamination in other environments, and the link between climate and contaminant transport suggests local or global climate change will have an impact on contaminant distribution and fate.

Past Leaded Gasoline Emissions As A Nonpoint Source Tracer In Riparian Systems: A Study Of River Inputs To San Francisco Bay, Charles E. Dunlap, Robin Bouse, A. Russell Flegal

Charles Dunlap

Variations in the isotopic composition of lead in 1995- 1998 river waters flowing into San Francisco Bay trace the washout of lead deposited in the drainage basin from leaded gasoline combustion. At the confluence of the Sacramento and San Joaquin rivers where they enter the Bay, the isotopic compositions of lead in the waters define a linear trend away from the measured historical compositions of leaded gas in California. The river waters are shifted away from leaded gasoline values and toward an isotopic composition similar to Sierra Nevadan inputs which became the predominant source of sedimentation in San Francisco Bay …

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

Ram S. Mohan

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

Ram S. Mohan

No abstract provided.