Physics and Engineering.

Chair: T.M. Parchure, US Army Engineers, WES 

Vice-chair: Atef Elsherbeni, University of Mississippi 

FRIDAY MORNING

Caribbean

8:45 Divisional Poster Session

A BLUEPRINT FOR DEVELOPING A LIQUID CRYSTALS RESEARCH CENTER

Francis Tuluri, Jackson State University, Jackson, MS 39217

The present work explores the feasibility studies of developing a Liquid Crystals Research Center. Liquid Crystals is a multidisciplinary area of research and is linked to a wide range of disciplines like Condensed Matter Physics, Materials Science and Electronics Engineering. Liquid crystals exhibit interesting properties covering a wide variety of physical phenomena--elastic, dielectric, optical, phase transitional. Of several other parameters that characterize the physical phenomena of liquid crystals the important ones are elastic constants, dielectric parameters like permittivity and loss, birefringence, viscosity, density, switching times, patterns of the textures. Further, Ferroelectric Liquid Crystals have a significant role in both the fundamental and electronic display technology. Basically a Liquid Crystals Research Center can be established with three modules--Teaching, Research and Training. Each of the modules can further be expanded into several other modules depending on time and budgetary considerations. At the end, the all the sub modules can be regrouped to serve under a center. The present work also examines the role of a LQRC towards recruitment and training of students in Physics, Materials Science and Electronics Engineering.

NUMERICAL ANAYSIS OF FORCE AND TORQUE IN MAGNETOSTATIC PROBLEMS USING MAGNETIC SCALAR POTENTIAL

Aik Min Choong, Charles E. Smith, and Atef Z. Elsherbeni*, University of Mississippi, University, MS 38677

The objective of this study is to investigate the magnetic potential distribution (U), magnetic flux density (B), and magnetic field intensity (H) in a computational domain and to compute the forces and the torque between magnetic materials for a static condition, with no time varying components present. In the case of static magnetic field conditions, only the magnetic flux density needs to be considered because the equations for electric and magnetic fields are decoupled. Thus, from the well-known Maxwell's equation for B, a Laplacian equation in terms of U can be found. The Finite Difference (FD) technique will be applied to approximate U to determine the potential distribution in the computational domain. In the process of solving such type of magnetic problems, computational time is a major concern, and this investigation explores several means for reducing the time requirements. The developed code for analyzing these type problems was written in Matlab and Fortran for comparing the computational time. Matlab provides the capability for plotting simulation results, but requires large amount of time to analyze the problem. However, Fortran is able to solve the problem in a much shorter time, but it requires another plotting program to plot its results. A commercially available software, Maxwell, is also used to generate results similar to these produced by Matlab and Fortran codes. Maxwell has the capability to analyze the magnetic problem in 2D or 3D and compute the force and torque. Examples of simulation results are presented that demonstrate potential field, force, and torques distributions for several conical configurations.

FINITE DIFFERENCE TIME DOMAIN SIMULATION OF ELASTIC WAVE PROPAGATION FOR DETECTING OBJECTS BURIED IN SOIL

Atef Z. Elsherbeni* and Paul L. Chin, University of Mississippi, University, MS 38677

Acoustic waves have shown, in recent years, significant success in detecting buried objects. Design of acoustic measurement devices calls for accurate numerical models to simulate acoustic wave propagation in inhomogeneous media. This paper presents a finite difference time domain (FDTD) formulation for the simulation of elastic wave propagation in poroelastic media that represents the soil and the fluid in its pore space. A first order hyperbolic leap-frog differential equation system is obtained from Biot's equations to represent the waves in the media. This system of equations is discretized on a staggered grid in time and space and is terminated by an absorbing boundary condition. This FDTD algorithm is used to study the interaction of elastic waves with mine-like objects buried in different types of soil. Numerical simulations are conducted and results are used to illustrate the advantage of using acoustic waves over electromagnetic waves in performing a more accurate detection.

Divisional Talks

9:00 THE HIGGS BOSON AND THE ORIGIN OF MASS

Amin Haque, Alcorn State University, Alcorn State, MS 39096

According to Higgs and other particle physicists, the fundamental constituent particles, quarks and leptons and the weak force carriers W and Z particles, acquire their masses by interacting with a force field, the Higgs field. This field permeates all space, similar in some ways to the electromagnetic field. We know from quantum theory that fields have particles associated with them, the photon being the particle for the electromagnetic field. So there must be a carrier particle associated with the Higgs field, and this is the Higgs boson. Different particles interact with the Higgs field with different strengths. Hence different particles have different mass. Some particles have no mass, because they don't interact with the Higgs field. Neutrinos barely interact with a Higgs boson, so they have a very small mass. Top quarks, which have about the mass of a gold atom, have the strongest interaction with a Higgs boson. Finding the Higgs boson is the key to whether Higgs' hypothesis for the origin of mass is indeed correct, and whether the Standard Model will survive. A small number of events have been reported that could be interpreted as resulting from Higgs bosons, but the evidence so far is not conclusive. The most probable mass for a Higgs boson is approximately 90 GeV. It is expected that the Large Hadron Collider at CERN, will be able to confirm the existence of Higgs bosons in or after 2005.

9:15 THE FUNDAMENTAL CONSTITUENT PARTICLES OF THE UNIVERSE AND THEIR INTERACTIONS

Amin Haque, Alcorn State University, Alcorn State, MS 39096

The building blocks of matter are the six quarks and six leptons. All matter is made from first generation particles, because the second and third generation particles are unstable and quickly decay into stable first generation particles. A proton is made of two u-quarks (charge +2/3) and one d-quark (charge -1/3), whereas a neutron ismade of two d-quark and one u-quark. Physicists have found that all matter in the universe is made from quarks and electrons. Forces drive the interactions between the matter particles. Without the four fundamental forces--gravity, electromagnetic, the strong force, and the weak force--the universe could not exist. The corresponding force carrier particles are graviton (not yet discovered), photon, gluon, and W and Z. Matter particles and force carrier particles, and the last three forces are part of the Standard Model. All the particles predicted by the Standard Model have been found except the Higgs boson, the force carrier particle associated with the Higgs field, which is believed to be the mechanism by which all particles acquire their mass. In June 2003 physicists announced that they had created a new form of matter called quark-gluon plasma at Brookhaven National Laboratory's Relativistic Heavy Ion Collider. It is expected that the Large Hadron Collider at CERN, will be able to confirm the existence of Higgs bosons. The Standard Model, however, does not currently answer certain questions, and, therefore, may be an incomplete theory.

9:30 SEDIMENT SUSPENSION INDUCED BY VESSEL TRAFFIC IN MISSISSIPPI RIVER

T.M. Parchure, US Army Engineer Research and Development Center, Vicksburg, MS 39180

Resuspension and deposition of fine clayey sediment has a significant impact on aquatic plants and animals. The Upper Mississippi River navigation study included estimation of environmental impact caused by an increase in navigation traffic because vessel-induced waves cause bank erosion, which in turn increases sediment in suspension. Study objectives were to estimate maximum suspension concentration caused by events of vessel passage and time for deposition of suspended sediment. Towboats and recreational crafts were the two types of vessels considered. Vessel-generated wave heights, current and suspended sediment concentration were measured in the field. Available field data were analyzed for determining statistical parameters for each wave train and generalized patterns were evolved for model runs. Particle size distribution, organic content and bulk density of surface sediment samples was determined. Laboratory tests were conducted to determine erosion rates and the critical shear strength of bed material. A numerical sediment resuspension model was developed for predicting the concentration of suspended sediment in the nearshore zone consisting of mud with significant quantities of cohesive material. Model verification was achieved through use of field and laboratory data. Conclusions: 1. Large vessels generate large drawdown, small wave heights, and high sediment concentration. 2. Small vessels such as a yacht generate small drawdown and large wave heights. 3. At high speed, small vessels also cause a substantial increase in suspended sediment concentration. The estimated suspended sediment concentrations varied from 3 mg/l to 900 mg/l depending upon the type of sediment bed, water depth, and wave conditions. The sediment will remain in suspension for duration varying from a few minutes to several hours depending upon the turbulence level.

9:45 SUPERSTRING THEORY AND SUPERSYMMETRY OF FUNDAMENTAL PARTICLES

Amin Haque, Alcorn State University, Alcorn State, MS 39096

According to the Standard Model, the current fundamental units of mass, quarks and leptons, that form protons and neutrons, are actually made of still more fundamental units, Strings. Superstring theory is an attempt to unify the four fundamental forces of nature. According to this theory, all the particles of the universe and all the forces of interaction are made of extremely tiny fibers or strings vibrating with different frequencies, which correspond to different energies (and mass, E = m[c.sup.2] = hf) and force particles, charge, and spin of known elementary particles. String theory also predicts that for every known matter particle (quarks, electron, neutrino, etc) to have as-yet-undiscovered corresponding superforce carrier particle (photino, gluino, Wino, Zino, etc.) and every known force carrier particle (photon, gluon, W, Z, etc.) to have an as-yet-discovered corresponding supermatter particle (Squark, Selectron, Sneutrino, etc). This concept, known as supersymmetry, helps establish a relationship between matter particles and force carrier particles. The superparticle is thought to be more massive than its corresponding particle. According to this theory, the universe is not actually made up of the four commonly experienced dimensions, but may contain 10 or even 11 spacetime dimensions. Particle physicists do not yet understand the theory well enough to make definite testable predictions. However, they think that some of its features can be supported by circumstantial evidence: extra dimensions (10 or 11), superpartner particles, fluctuations in background radiation.

10:00 Break

10:15 ENVIRONMENTALLY BENIGN DESIGN AND MANUFACTURING

S. Kant Vajpayee, University of Southern Mississippi, Hattiesburg, MS 39406

We are now adopting more responsible ways of designing and manufacturing products for the global market. Economists are at last accepting the twin facts of finite resources and limited sinks. ISO 14000 is helping to change our thinking on business as usual. Companies have begun to feel proud of going green. When it comes to greenness, European Union is flexing its muscles to drag the United States. Innovations in science and technology are accelerating the transformation toward environmentally benign design and manufacture. The website http://www.wtec.org/loyola/ebm/ describes the types of efforts essential for such a transformation. A recent (2001) study has gathered "information on research and development around the world aimed at developing alternative methods for materials processing with the purpose of minimizing toxic material generation and optimizing products and byproducts for sustainability and reuse characteristics." From environmentally benign manufacturing (EBM) technologies viewpoint: "Europe leads in most governmental activities, Japan in industrial activities, and the results for research and development are mixed. The United States leads in financial and legal liability concerns, water conservation, decreased industrial releases to air and water, and research in polymers and long term electronics, but follows in all other areas. In the area of university educational activities, and both industry and government sponsorship of these, it is clear that Europe leads, followed by the United States and then Japan. Overall, therefore, the United States ranks third behind Europe and Japan.

10:30 ANALYSIS AND DESIGN OF A NOVEL COPLANAR WAVEGUIDE FED SLOT ANTENNA FOR ULTRA WIDEBAND APPLICATIONS

Abdelnasser A. Eldek, Atef Z. Elsherbeni*, and Charles E. Smith, University of Mississippi, University, MS 38677

In applications where loss, dispersion, size, weight, cost, performance, ease of installation, and aerodynamic profile are constrains, printed slot antennas are required. Moreover, in some applications like wireless and radar communications systems wide bandwidth and high gain are of the main design objectives. In this research, a novel printed slot antenna design fed by a coplanar waveguide is introduced and denoted as lotus antenna. The antenna is a modified version of the conventional slot dipole and bow-tie slot antennas that is recently designed by the authors for X-band operation. The lotus antenna is evolved from the smooth transition from the coplanar waveguide to the slot in a lotus shape. The bandwidth of the lotus antenna extends from 8 to more than 30 GHz. The antenna is fabricated and the return loss measurements agreed very well with the simulation results. Linear arrays of 8 and 16-element of this antenna are analyzed for gain enhancement. The main advantages of these arrays are the ultra wide bandwidth and low cross polarizations (less than 20 dB). The radiation pattern, return loss, coupling, directivity and gain of these arrays are computed and will be presented.

10:45 SIMPLIFIED FEEDING STRUCTURE FOR A MODIFIED PRINTED YAGI ANTENNA

Guiping Zheng*, Ahmed A. Kishk, Allen W. Glisson, and Alexander B. Yakovlev, University of Mississippi, University, MS 38677

A modified printed Yagi antenna with a simplified feeding mechanism is presented in this work. In this new design, a transmission line formed by two parallel strips printed on the opposite sides of the dielectric substrate is used to feed the printed Yagi antenna. The parallel strips are connected to a microstrip line with a truncated ground plane, which acts as a reflector in the printed Yagi antenna. Both the microstrip line and parallel strips are carefully designed with the characteristic impedance of 50 ohms. This feeding network is naturally operating in the odd mode starting from the feeding point for all frequencies. The driver length is chosen to be approximately a half of the wavelength at the central frequency used in the design and the length of parallel strips is chosen to be about a quarter of the wavelength. This simplified feeding structure results in the reduction of the transmission line length, and, consequently, the radiation losses. The analysis of the modified Yagi antenna is performed numerically using commercial FEM and FD-TD softwares.

11:00 SIMULATION OF ELECTROMAGNETIC SCATTERING FROM TWO DIMENSIONAL CHIRAL OBECTS USING AN ITERATIVE PROCEDURE

Mohamed H. Al Sharkawy and Atef Z. Elsherbeni*, University of Mississippi, University, MS 38677

An Iterative scattering procedure is developed to solve the problem of scattering from a two dimensional chiral objects simulated by circular cylinders, illuminated by either a TEz or a TMz plane wave. The developed formulation and the implemented code simulate different types of cylinders, where the cylinders can be made of either lossy or lossless anisotropic chiral material with uniform or non-uniform chiral admittance distribution, homogeneous isotropic dielectric material, perfectly conducting material or a combination of all of them. The technique applies the boundary conditions on the surface of each cylinder in an iterative procedure. After adequate number of interactions (theoretically infinite), the total scattered field is obtained based on summation from all interactions. Numerical verifications are presented to prove the validity of the formulation before presenting the scattering from an array of chiral

cylinders showing significant RCS reduction in forward or backward directions based on the selection of the chirality parameter.

11:15 Break

11:30 BAYESIAN INFERENCE TECHNIQUES FOR THE DESIGN OF ANTENNA ARRAYS

John. M. Earwood, Matthew J. Inman, Atef Z. Elsherbeni*, and Charles E. Smith, University of Mississippi, University, MS 38677

The design of antenna arrays is often challenging in that there are a large number of parameters that must be taken into account. Typically, the design of an antenna array is simplified by holding certain sets of parameters constant, such as the element spacing, so that other parameters, such as the element phasing and amplitudes, may be determined independently. Many analytic approaches, such as Fourier or Woodward-Lawson synthesis, have been used in the past to assist in the design of arrays. These methods, however, can be lacking in the flexibility that is often required in many cases. Conversely, trying to fully explore an array with many parameters becomes difficult due to computational limitations once the number of parameters becomes large. This paper deals with techniques employed to accurately sample from the parameter space to find the best set of parameters for a specified radiation pattern. Steps used to utilize these inference techniques using modern programming languages will be discussed. This will show how a program can employ the Bayesian techniques in an efficient manner. Results will show good match with the specified radiation patterns in many cases.

11:45 MODIFIED PERFECTLY MATCHED LAYERS METHOD FOR PERIODIC STRUCTURES

Guiping Zheng*, Ahmed A. Kishk, Allen W. Glisson, and Alexander B. Yakovlev, University of Mississippi, University, MS 38677

In this work, a modified Perfectly Matched Layer (PML) method for periodic structures is presented. In many applications, the structures have a periodicity in one or two dimensions, such as a frequency selective surface (FSS), a photonic bandgap (PBG) structure, or an infinite antenna array. The finite-difference time-domain (FDTD) technique has been successfully used to analyze the characteristics of these kinds of structures by applying the proper periodic boundary conditions (PBC). Because the periodicity is in one or two dimensions, the other sides of the structure in the FDTD analysis are required to be truncated by PML, which has been proven to be very effective for this purpose. Due to the difficulties that involve the time delay and time advance across the grid when modeling these periodic structures in direct way, field transformations are introduced to remove the time gradient across the grid. Therefore, PML procedure used to truncate the FDTD computational domain must also be applied to these field transformations so that they can absorb the outgoing waves properly. In this work, the transformed PML has successfully modeled a 2D PBG structure with different incident angles. This method did not require the integral form in the transmitted fields and is more efficient than the Uniaxial PML (UPML). The transformed PML in the 3D case will also be investigated in our future work.

FRIDAY AFTERNOON

Caribbean

1:30 E-WASTE A UNIVERSAL PROBLEM

Pao-Chiang Yuan, Jackson State University, Jackson, MS 39217

E-Waste is the fastest growing solid waste problem in the country and in this century. E may stand for electricity or electronic. This research mainly focuses on Electronic Waste, with emphasis on computers and cellular telephones. Everyday we develop new technologies, but we also generate a lot of other materials we do not expect. Are we responsible for them? Yes. What happens to these materials after their end-of-useful life? Well, for most of us, we place them in the trash. Most people's attitude is to not care because it is not their problem. This, "not in my mind" and "not in my backyard" syndrome should be changed. We have to remember that none of these materials used on computers or cellular phones is biodegradable. If you bury them, they may be in the landfill forever, and if you burn them, they may generate dioxin and toxic products. Today, most homes have one or more computers and cellular phones. One computer is being used and another may be stored in the attic, garage, and basement or is for just decoration. This research presents the problem caused by computers and cellular phones. We will also investigate adverse health effects and the experiences we encounter in our recycling program at Jackson State University. Additionally, we will use Toxic Characteristic and Leaching Procedure (TCLP) test to examine the major parts of the computers and cellular phones to show their hazardous properties, all of them exceeds the EPA (Environmental Protection Agency) regulatory levels.

1:45 YOU WANT AN EXPLOSION? I GOT YOUR EXPLOSION RIGHT HERE!

John Patrick Lestrade, Mississippi State University, MS 39762

From their discovery in the mid 60s until the launch of a dedicated orbiting observation platform in 1991, gamma-ray bursts (GRB) were studied by only a handful of scientists. During that time, GRB were believed to be rather benign events related to neutron stars in our galaxy. However, observations over the past decade have shown that these bursts of gamma rays originate, not in nearby space, but in very distant galaxies. The knowledge of their immense distances, coupled with the observations of high gamma-ray fluxes, have brought the realization that these are the largest explosions in our universe since the Big Bang. The continuing mystery of what could cause such violent bursts has attracted increasing numbers of GRB enthusiasts, astronomers from each of the domains of the electromagnetic spectrum, mathematicians, science fiction writers, and even trekkies (Graf, L. 2000 in Star Trek: New Earth.) In this presentation I will summarize the currently-accepted burster models and describe the ramifications if one were to explode in our part of the Milky Way.

2:00 AN AUTOREGRESSIVE MODEL OF GAMMARAY BURST TIME PROFILES

Daniel Logue (1)*, John Patrick Lestrade (1), Jane Harvill (1), Jean-Luc Atteia (2), and Roggie Boone (3), (1) Mississippi State University, MS 39762; (2) Observatoire Midi-Pyrennees, Toulouse, France; and (3) Valdosta State University, GA 31698

Gamma-ray bursts (GRB) are highly energetic explosions of unknown cosmic origin with extremely complicated time profiles. The asymmetric features and stochastic jumps in these profiles clearly call for a nonlinear statistical analysis of the data. Of the infinitely large class of nonlinear models, we have chosen the univariate functional coefficient autoregressive (FCAR) models. Our general equation for a GRB time series is C(t)=F(Y(t-d))*C(t-1)+e(t) where C(t) is the burst count rate at time t, Y is an independent exogenous variable, F(Y) is the general functional coefficient, d is the time lag (usually zero), and e is random noise with finite variance. Examples of possible exogenous variables are: (1) count rate at an earlier time in the burst itself, in which case d [greater than or equal to] 1, (2) time, or (3) the relative average energy (hardness) of the photons in a time interval. Initial analyses of the pre-burst background, using the count rate at lag 1 as the exogenous variable, have resulted in the expected linear coefficients. Any departure from linearity is indicative of a departure from randomness. We find hints of specific non-linear trends in the burst portion of the data. However, because of the low signal-to-noise ratio of most bursts, we may need to invoke smoothing methods that would more clearly yield the intrinsic burst characteristics.

2:15 MAPPING ANOMALIES IN THE EARTH'S MAGNETIC FIELD WITH THE GAMMA-RAY BURST DETECTOR, FREGATE 

Brad Newton Barlow (1)*, John Patrick Lestrade (1), and Jean-Luc Atteia (2), (1) Mississippi State University, Mississippi State, MS 39762, and (2) Observatoire Midi-Pyrennees, Toulouse, France

To a first approximation, the Earth's magnetic field is a slightly-tilted dipole offset from the center of our planet. A peculiar feature of this field is the South Atlantic Anomaly (SAA), a weak spot off the east coast of Argentina/Brazil where radiation-belt particles are able to penetrate to low altitudes. The SAA is problematic for many orbiting x-ray and gamma-ray detectors because the high fluxes of charged particles can result in false triggers and sometimes cause damage to spacecraft circuitry. To further complicate the picture, Tamagawa et al. (2003) present evidence of a second, transient, SAA-like magnetic field weakness that is near Ecuador. We use the orbital data of FREGATE, a set of gamma-ray burst detectors that are flying on the HETE-2 satellite, to search for recurring features caused by these and other possible field weaknesses. One goal is to corroborate the presence of the Equador Anomaly and help define its temporal behavior.

2:30 Divisional Business Meeting