Physical Sciences and Mathematics Commons^™

On A Simple Derivation Of The Fresnel Diffraction Formula And A Transfer Function Approach To Wave Propagation, Partha P. Banerjee, Ting-Chung Poon

Partha Banerjee

The Fresnel diffraction formula is straightforwardly obtained by solving a partial differential equation (PDE) for envelope propagation using Fourier transform techniques. The PDE, in turn, can be derived from the dispersion relation of a linear medium by employing a simple operator formalism. The transfer function and impulse response of propagation follows as a spin‐off and is used to solve illustrative problems. Huygens’ principle is visualized as a consequence of the convolution property of linear systems.

Notch Spatial Filtering With An Acousto-Optic Modulator, Partha P. Banerjee, Dongqing Cao, Ting-Chung Poon

Partha Banerjee

The role of acousto-optic (AO) modulators in programmable real-time image processing has recently been demonstrated. For fully investigating the image-processing capabilities of the AO modulator, general techniques to derive spatial transfer functions are needed for a variety of physical situations. We develop a technique to determine the spatial transfer functions numerically for various cases of beam incidence on an AO modulator. Normal incidence and incidence at twice the Bragg angle are investigated as examples for which double-sided and single-sided notch spatial filtering, respectively, are achieved. The observed spatial-filtering characteristics are reconciled with simple intuitive physical arguments.

Nonlinear Transverse Effects In Second-Harmonic Generation, Pawel Pliszka, Partha P. Banerjee

Partha Banerjee

We study a three-dimensional model of interaction of fundamental-frequency and second-harmonic beams in a quadratically nonlinear medium. Numerical simulations of the three-dimensional propagation problem in the presence of diffraction and anisotropy are performed under the paraxial approximation. The role of the transverse effects in various regimes is investigated. We demonstrate the effect of phase modulation and an induced nonlinear focusing during the interaction of the fundamental frequency with the generated second harmonic.

Multiwave Coupling In A High-Gain Photorefractive Polymer, Kenji Matsushita, Partha P. Banerjee, S. Ozaki, Daisuke Miyazaki

Partha Banerjee

The characteristics of a new high-gain photorefractive polymer composite with a PNP chromophore are investigated. Competition between beam fanning and two-wave coupling (TWC) is predicted and verified experimentally. The intensity dependence of TWC gain is studied. Higher diffraction order and forward phase conjugation in a TWC geometry are observed and explained.

Linear And Nonlinear Propagation In Negative Index Materials, Partha P. Banerjee, George Nehmetallah

Partha Banerjee

We analyze linear propagation in negative index materials by starting from a dispersion relation and by deriving the underlying partial differential equation. Transfer functions for propagation are derived in temporal and spatial frequency domains for unidirectional baseband and modulated pulse propagation, as well as for beam propagation. Gaussian beam propagation is analyzed and reconciled with the ray transfer matrix approach as applied to propagation in negative index materials. Nonlinear extensions of the linear partial differential equation are made by incorporating quadratic and cubic terms, and baseband and envelope solitary wave solutions are determined. The conditions for envelope solitary wave solutions …

Application Of Up-Sampling And Resolution Scaling To Fresnel Reconstruction Of Digital Holograms, Logan Williams, George Nehmetallah, Rola Aylo, Partha P. Banerjee

Partha Banerjee

Fresnel transform implementation methods using numerical preprocessing techniques are investigated in this paper. First, it is shown that up-sampling dramatically reduces the minimum reconstruction distance requirements and allows maximal signal recovery by eliminating aliasing artifacts which typically occur at distances much less than the Rayleigh range of the object. Second, zero-padding is employed to arbitrarily scale numerical resolution for the purpose of resolution matching multiple holograms, where each hologram is recorded using dissimilar geometric or illumination parameters. Such preprocessing yields numerical resolution scaling at any distance. Both techniques are extensively illustrated using experimental results.

Achieving Enhanced Gain In Photorefractive Polymers By Eliminating Electron Contributions Using Large Bias Fields, C. M. Liebig, S. H. Buller, Partha P. Banerjee, S. A. Basun, Pierre-Alexandre Blanche, J. Thomas, Cory W. Christenson, N. Peyghambarian, Dean R. Evans

Partha Banerjee

Photorefractive polymers have been extensively studied for over two decades and have found applications in holographic displays and optical image processing. The complexity of these materials arises from multiple charge contributions, for example, leading to the formation of competing photorefractive gratings. It has been recently shown that in a photorefractive polymer at relatively moderate applied electric fields the primary charge carriers (holes) establish an initial grating, followed by a subsequent competing grating (electrons) resulting in a decreased two-beam coupling and diffraction efficiencies. In this paper, it is shown that with relatively large sustainable bias fields, the two-beam coupling efficiency is …

3d Visualization Using Pulsed And Cw Digital Holographic Tomography Techniques, George Nehmetallah, Partha P. Banerjee, D. Ferree, R. Kephart, Sarat C. Praharaj

Partha Banerjee

We outline the use of digital holographic tomography to determine the three-dimensional (3D) shapes of falling and static objects, such as lenslets and water droplets. Reconstruction of digitally recorded inline holograms is performed using multiplicative and Radon transform techniques to reveal the exact 3D shapes of the objects.

Giants Among Micromorphs: Were Cincinnatian (Ordovician, Katian) Small Shelly Phosphatic Faunas Dwarfed?, Benjamin F. Dattilo, Rebecca L. Freeman, Winfried S. Peters, William P. Heimbrock, Bradley Deline, Anthony J. Martin, Jack W. Kallmeyer, Jesse Reeder, Anne Argast

Winfried S. Peters

Reply To “Comment On Gravitational Slingshot,” By C. L. Cook [Am. J. Phys. 73 (4), 363 (2005)], Asim Gangopadhyaya, Asim Gangopadhyaya, Robert Cacioppo, John Dykla

Asim Gangopadhyaya

No abstract provided.

Kl−Ks Mass Difference And Supersymmetric Left-Right-Symmetric Theories, Asim Gangopadhyaya

Asim Gangopadhyaya

The supersymmetric contributions to the K_L−K_S mass difference makes the previously obtained bounds on the right-handed scale (M_R>1.6 TeV) much weaker. This raises the interesting possibility that the left-right model could be tested as an alternative to SU_L(2)⊗U(1) at low energies. Also we find that to demand that the supersymmetric contribution to the K_L−K_S mass difference be less than 3.5×10⁻¹⁵ GeV requires that scalar-quark masses be more than 400 GeV.

Approaching A Universal Scaling Relationship Between Fracture Stiffness And Fluid Flow, David Nolte, Laura Pyrak-Nolte

David D Nolte

Self-Assembling Biomolecular Catalysts For Hydrogen Production, Dustin Patterson

Dustin Patterson

Needs Assessment: A Report On Seven Focus Groups In Ohio, Kevin O'Brien, Daniel Baracskay, Wendy Kellogg, Michael Mcgoun, Claudette Robey, Michael Tevesz, Kirstin Toth

Michael J. Tevesz

A series of seven focus groups were conducted in various locations throughout northern Ohio to identify and assess coastal resources management training needs across the Ohio Great Lakes basin. The focus groups were comprised of a cross-section of professionals who make decisions affecting watershed areas or Lake Erie coastal areas. Six of the focus groups included decision-makers considered previous and potential users of coastal resources management training (non-providers). A seventh focus group included decision-makers who provide training in coastal resources management (providers).

Spectroscopic And Functional Characterization Of The Nitric Oxide Adducts Of The Fe(Iii) And Fe(Ii) States Of The Co-Sensing Transcription Factor, Cooa, From Carboxydothermus Hydrogenoformans, Robert Clark, Edra Jani, Arathi Francis, Elise Laroche, Isabel Malone

Robert Clark

CooA is a carbon monoxide (CO) sensing transcription factor that is found in several bacteria and regulates CO metabolism. CO binding to CooA’s heme groups initiates a conformation change that activates protein DNA binding. This study investigates the reaction of Fe(III) Carboxydothermus hydrogenoformansCooA (Ch CooA) with nitric oxide (NO). Previously, Clark and coworkers reported Fe(II) Ch CooA bound NO to form a 6-coordinate (6-C) Fe(II)-NO adduct that was active for DNA binding in vivo and in vitro. This is in contrast to the best studied CooA homolog from R. rubrum (Rr) that was exquisitely specific for CO and formed an …

The Effect Of Latency On User Performance In Warcraft Iii, Nathan Sledon, Eric Girard, Seth Borg, Mark Claypool, Emmanuel Agu

Emmanuel O. Agu

Variable latency on the Internet is a well-known problem for interactive applications. With the increase in interactive network games comes the increased importance of understanding the effects of latency on user performance. Classes of network games such as First Person Shooters (FPS) and Read Time Strategy (RTS) differ in their user interaction model and hence susceptibility to variable latency. While previous work has measured the effects of latency on FPS games, there has been no systematic investigation of the effects of latency on RTS games. In this work, we design and conduct user studies that measure the impact of latency …

Low Delay Marking For Tcp In Wireless Ad Hoc Networks, Choong-Soo Lee, Mingzhe Li, Emmanuel Agu, Mark Claypool, Robert Kinicki

Emmanuel O. Agu

End-hosts on wireless ad hoc networks typically use TCP as their transport layer protocol. Being designed for wired networks, TCP can perform poorly over wireless networks. Work that has proposed ways to improve TCP performance over wireless networks has concentrated primarily on improving TCP throughput only. Emerging applications, such as interactive multimedia and network games, require reduced delay at least as much as increased throughput. In this paper, we propose LDM1, an IP layer queue marking mechanism that estimates the number of hops and flows at each wireless node to computes the optimal marking probability. We present simulation results and …

Full Isolation Number Of Matrices: Some Extremal Results, David Tate, David Brown

David C. Brown

A set of nonzero entries of a (0,1)-matrix is an isolated set if no two entries belong to the same row, no two entries belong to the same column, and no two entries belong to a submatrix of the form [1 1; 1 1]. The isolation number of a matrix is the maximum size over all isolated sets. The isolation number of a matrix is a well-known and well-used lower bound for the matrix's Boolean rank. We will discuss the isolation number of the adjacency matrix of various graphs and develop some extremal results for n x n matrices with …

Use Of Cryoelectronics To Reduce Power Losses, Christopher Hawley, Steve Gower, Dominic Cuiuri

Dominic Cuiuri

The operational characteristics of power electronics operating at ambient temperatures are well known. Less well known are the characteristics of these devices when operating at cryogenic temperatures. This emerging field is known as cryoelectronics. The primary driver for operation at reduced temperatures is the promise of a resultant reduction in device operation losses. The operating characteristics of Metal Oxide Silicon Field Effect Transistors (MOSFETs) and Insulated Gate Bipolar Transistors (IGBTs) at Liquid Nitrogen (LN) temperature have been experimentally analysed. The results have been used to evaluate the viability of using cryoelectronics in medium - high power applications, considering trade-offs between …

Time-Partitioned Index Design For Adaptive Multi-Route Data Stream Systems Utilizing Heavy Hitter Algorithms, Karen Works, Elke Rundensteiner, Emmanuel Agu

Emmanuel O. Agu

Adaptive multi-route query processing (AMR) is a recently emerging paradigm for processing stream queries in highly fluctuating environments. AMR dynamically routes batches of tuples to operators in the query network based on routing criteria and up-to-date system statistics. In the context of AMR systems, indexing, a core technology for efficient stream processing, has received little attention. Indexing in AMR systems is demanding as indices must adapt to serve continuously evolving query paths while maintaining index content under high volumes of data. Our proposed Adaptive Multi-Route Index (AMRI) employs a bitmap time-partitioned design that while being versatile in serving a diverse …

Harmonic Allocation Following Iec Guidelines Using The Voltage Droop Concept, V. Gosbell, Robert Barr

Robert Barr

Present IEC guidelines are difficult to apply to realistic cases because of the data load, the number of assumptions required and the computational complexity. A new approach is given based on the concept of voltage droop, to be detailed in a companion paper. The benefits of the approach are a simple calculation with minimal data and no required assumptions. It applies to radial or meshed distribution systems where feeders are sufficiently short that line capacitance can be ignored. The approach can be applied at the installation (MV or LV) and the equipment level and can be used to give reference …

New Exactly Solvable Hamiltonians - Shape Invariance And Self-Similarity, David Barclay, Ranabir Dutt, Asim Gangopadhyaya, Avinash Khare, A. Pagnamenta, Uday Sukhatne

Asim Gangopadhyaya

We discuss in some detail the self-similar potentials of Shabat and Spiridonov which are reflectionless and have an infinite number of bound states. We demonstrate that these self-similar potentials are in fact shape invariant potentials within the formalism of supersymmetric quantum mechanics. In particular, using a scaling ansatz for the change of parameters, we obtain a large class of new, reflectionless, shape invariant potentials of which the Shabat-Spiridonov ones are a special case. These new potentials can be viewed as q-deformations of the single soliton solution corresponding to the Rosen-Morse potential. Explicit expressions for the energy eigenvalues, eigenfunctions and transmission …

Performance Enhancement Of Tfrc In Wireless Networks, Mingzhe Li, Emmanuel Agu, Mark Claypool, Robert Kinicki

Emmanuel O. Agu

The TCP-Friendly Rate Control (TFRC) is used as a streaming media transport protocol. Using the TCP congestion response function and current network conditions, TFRC adjusts its transmission rate to yield the maximum TCP-Friendly throughput when sharing capacity with TCP flows. Since TFRC was designed for wired networks, it does not achieve the maximum TCP-Friendly throughput in multihop ad hoc wireless networks. The reduced wireless spatial channel reuse due to hidden terminals in multihop wireless networks induces TFRC throughput reductions. Specifically, TFRC is unaware of MAC layer transmission delays due to collisions, retransmissions and MAC layer congestion. This paper illustrates that …

Nilgai Antelope In Northern Mexico As A Possible Carrier For Cattle Fever Ticks And Babesia Bovis And Babesia Bigemina., E Cardenas-Canales, J. Alfonso Ortega-Santos, Tyler A. Campbell, Zeferino Garcia-Vaquez, Antonio Cantu-Covarrubias, Julio Figueroa-Millian, Randy W. Deyoung, David G. Hewitt, Fred Bryant

Fred B. Bryant

Of 20 blood samples from nilgais from Me´ xico, five were polymerase chain reaction-positive for Babesia bigemina and one for Babesia bovis. Positive samples had the expected 170 (B. bigemina) and 291 (B. bovis) base pairs and were identical to Gen-Bank B. bigemina accession S45366 and B. bovis M38218.

Generation Of A Complete Set Of Additive Shape-Invariant Potentials From An Euler Equation, Jonathan Bougie, Asim Gangopadhyaya, Jeffrey Mallow

Asim Gangopadhyaya

In supersymmetric quantum mechanics, shape invariance is a sufficient condition for solvability. We show that all conventional additive shape-invariant superpotentials that are independent of ħ can be generated from two partial differential equations. One of these is equivalent to the one-dimensional Euler equation expressing momentum conservation for inviscid fluid flow, and it is closed by the other. We solve these equations, generate the set of all conventional shape-invariant superpotentials, and show that there are no others in this category. We then develop an algorithm for generating all additive shape-invariant superpotentials including those that depend on ħ explicitly.

Supersymmetry And The Tunneling Problem In An Asymmetric Double Well, Asim Gangopadhyaya, Prasanta Panigrahi, Uday Sukhatne

Asim Gangopadhyaya

The techniques of supersymmetric quantum mechanics are applied to the calculation of the energy difference between the ground state and the first excited state of an asymmetric double well. This splitting, originating from the tunneling effect, is computed via a systematic, rapidly converging perturbation expansion. Perturbative calculations to any order can be easily carried out using a logarithmic perturbation theory. Our approach yield substantially better results than alternative widely used semiclassical analyses.

Mechanism Of Redox- And Co-Sensing By The Heme Protein, Cooa: Cryoradiolysis Studies, Robert Clark, Deanna Kalafut

Robert Clark

Gas-sensing heme proteins participate in a variety of signal-transduction mechanisms across a broad range of biological systems. This class of proteins functions by undergoing an allosteric conformational change in response to the binding of a small gas molecule to a heme group. CooA, which is a redox- and CO-sensing transcription factor that is found in several bacteria, regulates gene expression that enables growth on CO as a sole energy source. In the current study, we have employed the technique of gamma-irradiation / cryoreduction spectroscopy (cryoradiolysis) to investigate facile changes that occur to the heme coordination structure of CooA during activation. …

Discovering A Research Agenda For Using Design Rationale In Software Maintenance, Janet Burge, David Brown

David C. Brown

Design Rationale consists of the reasons behind decisions made while designing. This information would be particularly useful during software maintenance. In this paper, we describe a study performed to investigate the content, structure, and use of design rationale during maintenance. The major goal of this study was to discover an agenda for further research into the use of design rationale for software maintenance.

Measuring The Performance Gains From Directional Antennas In An Unplanned 802.11b Mesh Network, Jason Wilson, Patrick Gemme, Emmanuel Agu

Emmanuel O. Agu

Wireless mesh networks are becoming increasingly popular. Most proposed mesh algorithms are evaluated using simulation. Simulations frequently oversimplify real world scenarios and can lead to results that are significantly different. Thus, although it is more difficult to run controlled experiments in already deployed real-world networks, it is important to understand how proposed improvements perform under these realistic scenarios. Several authors have suggested the use of directional antennas, but their merits have only comprehensively evaluated in simulators. Roofnet is an unplanned 802.11b wireless mesh network deployed by MIT and is constructed primarily of omni-directional antennas. We use measurements to evaluate performance …

Inferring Unobservable Learning Variables From Students’ Help Seeking Behavior, Ivon Arroyo

Ivon Arroyo

Results of an evaluation of students’ attitudes and their relationship to student behaviors within a tutoring system are presented. Starting from a correlation analysis that integrates survey-collected student attitudes, learning variables, and behaviors while using the tutor, we constructed a Bayesian Network that infers attitudes and perceptions towards help and the tutoring system.