Physical Sciences and Mathematics Commons^™

Reconstruction Of Solar Irradiance Since 1610: Implications For Climate Cbange, Judith Lean, Juerg Beer, Raymond S. Bradley

Raymond S Bradley

Solar total and ultraviolet (UV) irradiances are reconstructed annually from J610 to the present. This epoch ~ludes the Maunder Minimmn of anomalously low solar activi1}' (circa 1645-1115) and the subsequent increase to the high levels of the present Modem Maximum. In this reconstruction, the Schwabe (II-year) irradiaoce cycle and a longer term Variability component are determined separately, based on contemporary. solar and stellar monitoring. The correlation of reconstructed solar irradiance and Northern Hemisphere (NIl) surface temperature is 0.86 in the pre-industrial period from 1610 to 1800, implying a predominant solar influence. Extending this correlation to the present suggests that solar …

Bulletin No. 34: Tidal Marshes Of Long Island Sound: Ecology, History And Restoration, Glenn D. Dreyer, William A. Niering

Bulletins

No abstract provided.

Local Magnetic Properties Of Antiferromagnetic Febr2, J. Peloth, R. A. Brand, Takele Seda, M. M. Pereira De Azevedo, W. Kleeman, Ch. Binek, J. Kushauer, D. Bertrand

Physics & Astronomy

The antiferromagnet FeBr₂ has been studied by Mössbauer spectroscopy in external fields both in the metamagnetic region below the multicritical temperature T_MCP and in the second-order transition region above. The local magnetization shows that the metamagnetic transition occurs by spin flips, as in simple models. However, in the second-order transition region, the local magnetization of the sublattice oriented antiparallel to the external field varies continuously but remains parallel to the c axis. This can only be understood if the external magnetic field induces strong transversal spin precession of the moments on the antiparallel sublattice. This shows that the …

Synthesis And Characterization Of A Water-Soluble Metallopeptide That Resembles A Parallel Beta-Pleated Sheet, Michael Y. Ogawa, Alexei B. Gretchikhine, Sunil-Datta Soni, Steven M. Davis

Chemistry Faculty Publications

The title metallopeptide consists of two divalinyl peptides attached to the carboxylate groups of the ruthenium polypyridyl complex. [Ru(bpy)(2)L](2+): bpy = 2,2'-bipyridine; L = 3,5-dicarboxy-2,2'-bipyridine. The charged ruthenium complex is water soluble and is shown by variable temperature, and 2-D NMR to consist a parallel arrangement of interacting, extended peptide strands that ir reminiscent of the beta-sheet structure. Circular dichroism results support this assignment.

Simulations Between Programs As Cellular Automata, Howard A. Blair, Fred Dushin, Polar Humenn

Electrical Engineering and Computer Science - Technical Reports

We present cellular automata on appropriate digraphs and show that any covered normal logic program is a cellular automaton. Seeing programs as cellular automata shifts attention from classes of Herbrand models to orbits of Herbrand interpretations. Orbits capture both the declarative, model-theoretic meaning of programs as well as their inferential behavior. Logically and intentionally different programs can produce orbits that simulate each other. Simple examples of such behavior are compellingly exhibited with space-time diagrams of the programs as cellular automata. Construing a program as a cellular automaton leads to a general method for simulating any covered program with a Horn …

Designing Dependencies, Howard A. Blair

Electrical Engineering and Computer Science - Technical Reports

Given a binary recursively enumerable relation R, one or more logic programs over a language L can be constructed and interconnected to produce a dependency relation D on selected predicates within the Herbrand base BL of L isomorphic to R. D can be, optionally, a positive, negative or mixed dependency relation. The construction is applied to representing any effective game of the type introduced by Gurevich and Harrington, which they used to prove Rabin's decision method for S2S, as the dependency relation of a logic program. We allow games over an infinite alphabet of possible moves. We use this representation …

Complex Dynamics And Multistability In A Damped Harmonic Oscillator With Delayed Negative Feedback, Sue Ann Campbell, Jacques Bélair, Toru Ohira, John Milton

WM Keck Science Faculty Papers

A center manifold reduction and numerical calculations are used to demonstrate the presence of limit cycles, two-tori, and multistability in the damped harmonic oscillator with delayed negative feedback. This model is the prototype of a mechanical system operating with delayed feedback. Complex dynamics are thus seen to arise in very plausible and commonly occurring mechanical and neuromechanical feedback systems.

Effect Of Disorder On Synchronization In Prototype 2-Dimensional Josephson Arrays, Adam S. Landsberg, Yuri Braiman, Kurt Wiesenfeld

WM Keck Science Faculty Papers

We study the effects of quenched disorder on the dynamics of two-dimensional arrays of overdamped Josephson junctions. Disorder in both the junction critical currents and resistances is considered. Analytical results for small arrays are used to identify a physical mechanism which promotes frequency locking across each row of the array, and to show that no such locking mechanism exists between rows. The intrarow locking mechanism is surprisingly strong, so that a row can tolerate large amounts of disorder before frequency locking is destroyed.

Secure Trapdoor Hash Functions Based On Public-Key Cryptosystems, Gary R. Greenfield, Sarah Agnes Spence

Department of Math & Statistics Technical Report Series

In this paper we systematically consider examples representative of the various families of public-key cryptosystems to see if it would be possible to incorporate them into trapdoor hash functions, and we attempt to evaluate the resulting strengths and weaknesses of the functions we are able to construct. We are motivated by the following question:

Question 1.2 How likely is it that the discoverer of a heretofore unknown public-key cryptosystem could subvert it for use in a plausible secure trapdoor hash algorithm?

In subsequent sections, our investigations will lead to a variety of constructions and bring to light the non-adaptability of …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 11, Number 10, December 1995, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A twelve page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

An Automated Search For Variability In Chromospherically Active Stars, Gregory W. Henry, Francis C. Fekel, Douglas S. Hall

Information Systems and Engineering Management Research Publications

We have completed an automated photometric survey of 66 potential or known chromospherically active late-type stars with the 0.4 m Vanderbilt/Tennessee State robotic telescope. The precision of the observations from this telescope matches that predicted from photon and scintillation noise alone and represents a significant improvement in the precision of previous robotic telescope surveys of chromospherically active stars. Light variability has been detected and its period has been determined for 47 stars, 41 of which are newly discovered variables. The primary mechanism of variability is rotational modulation of a spotted surface. In addition we have detected eclipses in HD 62668 …

Bit-Sequences: A New Cache Invalidation Method In Mobile Environments, Jin Jing, Ahmed K. Elmagarmid, Abdelsalam Helal, Rafael Alonso

Department of Computer Science Technical Reports

No abstract provided.

Inverse Pattern Matching, Amihood Amir, Alberto Apostolico, Moshe Lewenstein

Department of Computer Science Technical Reports

No abstract provided.

Migrant Threads On Process Farms: Parallel Programming With Ariadne*, Edward Mascarenhas, Vernon Rego

Department of Computer Science Technical Reports

No abstract provided.

Lightweight Write Detection And Checkpointing For Fine-Grained Persistence, Antony L. Hosking, J. Eliot B. Moss

Department of Computer Science Technical Reports

No abstract provided.

The New Jersey Machine-Code Toolkit, Norman Ramsey, Mary F. Fernáyesndez

Department of Computer Science Technical Reports

No abstract provided.

Sliced Configuration Spaces For Curved Planar Bodies, Elisha Sacks, Chandrajit Bajaj

Department of Computer Science Technical Reports

No abstract provided.

Kenematic Tolerance Analysis, Leo Joskowicz, Elisha Sacks, Vijay Srinivasan

Department of Computer Science Technical Reports

No abstract provided.

Partitioned Data Management In Mobile Environments, Ahmed K. Elmagarmid, Jin Jing, Abdelsalam Helal, Rafael Alonso

Department of Computer Science Technical Reports

No abstract provided.

Pattern Matching Image Compression: Algorithmic And Empirical Results, Mikhail J. Atallah, Yann Génin, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Dispersal Dynamics In A Wind-Driven Benthic System, John A. Commito, S. F. Thrush, R. D. Pridmore, J. E. Hewitt, V. J. Cummings

Environmental Studies Faculty Publications

Bedload and water column traps were used with simultaneous wind and water velocity measurements to study postlarval macrofaunal dispersal dynamics in Manukau Harbour, New Zealand. A 12-fold range in mean wind condition resulted in large differences in water flow (12-fold), sediment flux (285-fold), and trap collection of total number of individuals (95-fold), number of the dominant infaunal organism (84-fold for the bivalve Macomona liliana), and number of species (4-fold). There were very strong, positive relationships among wind condition, water velocity, sediment flux, and postlarval dispersal, especially in the bedload. Local density in the ambient sediment was not a good predictor …

Probabilistic Knowledge Base Validation, Howard T. Gleason

Theses and Dissertations

Our work develops a new methodology and tool for the validation of probabilistic knowledge bases throughout their lifecycle. The methodology minimizes user interaction by automatically modifying incorrect knowledge; only the occurrence of incomplete knowledge involves interaction. These gains are realized by combining and modifying techniques borrowed from rule-based and artificial neural network validation strategies. The presented methodology is demonstrated through BVAL, which is designed for a new knowledge representation, the Bayesian Knowledge Base. This knowledge representation accommodates incomplete knowledge while remaining firmly grounded in probability theory.

Neutron Damage In Distributed Bragg Reflectors And Microcavity Lasers, Mark A. Suriano

Theses and Dissertations

Distributed Bragg Reflectors (DBRs) grown on a gallium-arsenide substrate for a solid state mirror and a vertical cavity surface emitting laser (VCSEL) were subjected to a neutron fluence to determine the sensitivity of the DBRs. The samples were irradiated at Ohio State University's 500 kW research reactor. Relative and absolute reflectance measurements were taken before and after each irradiation over a spectral band of 530 880 µm. Relative reflectance measurements showed that the irradiation did not cause any spectral shift over seven decades of neutron fluences. The reflectivity of the DBRs decreased from their initial measurements after being irradiated. The …

Model Of Chlorocarbon (Cfc-12) Chemisorption On Solid Rocket Motor Alumina Exhaust Particles, Gary E. Lund

Theses and Dissertations

Solid Rocket (SRMs) that power Titan IV rockets and Space Shuttles, exhaust large quantities of potentially ozone damaging pollutants directly into the stratosphere, while in powered flight. In the past, studies on potential stratospheric impact of the exhaust products from aluminum/ammonium perchlorate based SRMs have focused on the effect of gaseous HCl from SRMs on the stratosphere. Until recently, the impact of heterogeneous chemistry on stratospheric ozone was believed to be relatively insignificant. This research investigates the potential heterogeneous process of CFC-12 dissociative chemisorption on alumina surfaces and the release of reactive halogen species known to destroy ozone. Through a …

Dynamics Of Binary Liquids In Pores, J.C. Lee

Faculty Publications

A computer simulation is performed to study the dynamics of binary liquids in the pores of Vycor glasses. The pores are modeled with glass walls that form randomly interconnected tunnels. When the relaxation is probed with a particular wavelength, the time autocorrelation function depends on whether or not there is a significant periodic or quasiperiodic structure in the distribution of the walls with that wavelength. If there is not, the relaxation may be fitted as the sum of an exponential term and a nonexponential activated term. If there is, the relaxation shows a long-lasting tail that can be fitted by …

Design And Analysis Of Parallel Hierarchical Battlefield Simulation, Conrad P. Masshardt

Theses and Dissertations

The purpose of this research is to determine if hierarchically partitioning a discrete event battlefield simulation reduces runtime and, if reduction exists, to characterize the run time reduction given any particular partition configuration. A hierarchical discrete event simulation of a main battle tank was constructed. Implementations were built for both a single processor and a multiprocessing machine. The implementations used the Message Passing Interface to increase portability to other parallel and distributed configurations. Three test cases were generated and run on three parallel and distributed environments, a network of Sun SparcStation 20's, a Silicon Graphics Power Challenge, and a Paragon …

The Separation Of Aqueous Iron Species Found In Stepwise Complexation By Capillary Electrophoresis With Atomic Absorption Spectroscopy Detection, Robert E. Sutton

Dissertations

A capillary zone electrophoresis system was interfaced to an atomic absorption spectrom eter to permit the separation and detection o f various species of iron found in step wise complexation in aqueous solutions. The samples were introduced at the anodic end of the column employing the electroosmotic flow to drive all the species to the detector at the cathodic end. Aqueous solutions of iron(II) and iron (III) chloride salts were among the compounds studied. The buffer employed w as a 20 millimolar (2-[N-morpholino]ethanesulfonic acid adjusted to a pH of 6 with 6 .6 millimolar potassium hydroxide. The detection limit was …

Evaluation Of Bail-Down Test Methods For Characterizing Free Product Recoverability From An Aquifer, Laura L. Krol

Masters Theses

Determination of the occurrence and recoverability of free product impacting the subsurface environment has been an on-going challenge in the environmental industry. A simple and relatively inexpensive test to perform in the field is the free product bail-down test. Many authors have proposed various analysis methods using these data for the determination of different free product characteristics.

The purpose of this project was to determine the comparability and possible validity of bail-down test interpretation methods for predicting hydrocarbon hydraulic conductivity/transmissivity and true free product thickness. Bail-down test data collected from two sites were analyzed and interpreted using methods from the …

Methods For Generating Quasi-Exactly Solvable Potentials, Asim Gangopadhyaya, Avinash Khare, Uday P. Sukhatme

Physics: Faculty Publications and Other Works

We describe three different methods for generating quasi-exactly solvable potentials, for which a finite number of eigenstates are analytically known. The three methods are respectively based on (i) a polynomial ansatz for wave functions; (ii) point canonical transformations; (iii) supersymmetric quantum mechanics. The methods are rather general and give considerably richer results than those available in the current literature.

Effects Of Insulin And Insulin Mimetics On Antioxidant Enzyme Levels: In Vivo And In Vitro, Shikha Varma

Masters Theses

Tissue antioxidation status is considered to be an important factor for elucidating the etiology of diabetes and its physiological complications. This study was aimed to determine the in vivo antioxidant enzyme levels in the altered antioxidant status of diabetic rat liver with the treatment of two potent insulin mimetics, vanadium and selenate. The direct effects of vanadate, selenate, and zinc (another insulin mimetic) on the antioxidant enzyme levels in primary rat hepatocytes in culture was also determined. Levels of superoxide dismutase (SOD), catalase (CAT) and gluthahione peroxidase (GPX) were determined in both model systems.

In the vivo model, insulin treatment …