Physical Sciences and Mathematics Commons^™

A Novel Pulsed Corona Discharge Reactor Based On Surface Streamers For No Conversion From N2-O2 Mixture Gases, M. A. Malik, Karl H. Schoenbach

Bioelectrics Publications

A novel pulsed corona discharge reactor is described which utilizes surface-plasma along insulating surfaces. The electrodes are comprised of a stainless steel wire anode of 150 µm diameter stretched along the surface of a glass sheet and two parallel aluminum strips as cathodes. An eight-stage Marx bank, which provides 60 ns, 40-45 kV monopolar pulses, was used to produce the surface streamers in nitrogen-oxygen mixtures at atmospheric pressure. With increasing oxygen content, the energy efficiency for NO2 and O3 synthesis was found to increase. The energy efficiency is almost the same for the surface-plasma and volume-plasma. However, the surface-plasma was …

Analysis Of Interband, Intraband, And Plasmon Polariton Transitions In Silver Nanoparticle Films Via In Situ Real-Time Spectroscopic Ellipsometry, S. A. Little, R. W. Collins, S. Marsillac

Electrical & Computer Engineering Faculty Publications

The dielectric function of Ag nanoparticle films, deduced from an analysis of in situ real-time spectroscopic ellipsometry (RTSE) measurements, is found to evolve with time during deposition in close consistency with the film structure, deduced in the same RTSE analysis. In the nucleation regime, the intraband dielectric function component is absent and plasmon polariton behavior dominates. Only at nuclei contact, does the intraband amplitude appear, increasing above zero. Both intraband and plasmon amplitudes coexist during surface smoothening associated with coalescence. The intraband relaxation time increases rapidly after surface smoothening is complete, also in consistency with the thin film structural evolution.

Executable Architecture Research At Old Dominion University, Andreas Tolk, Johnny J. Garcia, Edwin A. Shuman

Computational Modeling & Simulation Engineering Faculty Publications

Executable Architectures allow the evaluation of system architectures not only regarding their static, but also their dynamic behavior. However, the systems engineering community do not agree on a common formal specification of executable architectures. To close this gap and identify necessary elements of an executable architecture, a modeling language, and a modeling formalism is topic of ongoing PhD research. In addition, systems are generally defined and applied in an operational context to provide capabilities and enable missions. To maximize the benefits of executable architectures, a second PhD effort introduces the idea of creating an executable context in addition to the …

Do We Need M&S Science?, Jose J. Padilla, Saikou Y. Diallo, Andreas Tolk

VMASC Publications

No abstract provided.

Electronically Enhanced Surface Diffusion During Ge Growth On Si(100), Ali Orguz Er, Hani E. Elsayed-Ali

Physics Faculty Publications

The effect of nanosecond pulsed laser excitation on surface diffusion during the growth of Ge on Si(100) at 250 °C was studied. In situ reflection high-energy electron diffraction was used to measure the surface diffusion coefficient while ex situ atomic force microscopy was used to probe the structure and morphology of the grown quantum dots. The results show that laser excitation of the substrate increases the surface diffusion during the growth of Ge on Si(100), changes the growth morphology, improves the crystalline structure of the grown quantum dots, and decreases their size distribution. A purely electronic mechanism of enhanced surface …

Parallel-Sparse Symmetrical/Unsymmetrical Finite Element Domain Decomposition Solver With Multi-Point Constraints For Structural/Acoustic Analysis, Siroj Tungkahotara, Willie R. Watson, Duc T. Nguyen, Subramaniam D. Rajan

Civil & Environmental Engineering Faculty Publications

Details of parallel-sparse Domain Decomposition (DD) with multi-point constraints (MPC) formulation are explained. Major computational components of the DD formulation are identified. Critical roles of parallel (direct) sparse and iterative solvers with MPC are discussed within the framework of DD formulation. Both symmetrical and unsymmetrical system of simultaneous linear equations (SLE) can be handled by the developed DD formulation. For symmetrical SLE, option for imposing MPC equations is also provided.

Large-scale (up to 25 million unknowns involving complex numbers) structural and acoustic Finite Element (FE) analysis are used to evaluate the parallel computational performance of the proposed DD implementation using …

Vehicular Ad Hoc Networks, Syed R. Rizvi, Stephan Olariu, Christina M. Oinotti, Shaharuddin Salleh, Mona E. Rizvi, Zainab Zaidi

Computer Science Faculty Publications

(First paragraph) Vehicular ad hoc networks (VANETs) have recently been proposed as one of the promising ad hoc networking techniques that can provide both drivers and passengers with a safe and enjoyable driving experience. VANETs can be used for many applications with vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. In the United States, motor vehicle traffic crashes are the leading cause of death for all motorists between two and thirty-four years of age. In 2009, the National Highway Traffic Safety Administration (NHTSA) reported that 33,808 people were killed in motor vehicle traffic crashes. The US Department of Transportation (US-DOT) estimates that …

Scaling Properties At Freeze-Out In Relativistic Heavy-Ion Collisions, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, B. D. Anderson, S. Bueltmann, I. Koralt, D. Plyku, Star Collaboration

Physics Faculty Publications

Identified charged pion, kaon, and proton spectra are used to explore the system size dependence of bulk freeze-out properties in Cu+Cu collisions at √sNN=200 and 62.4 GeV. The data are studied with hydrodynamically motivated blast-wave and statistical model frameworks in order to characterize the freeze-out properties of the system. The dependence of freeze-out parameters on beam energy and collision centrality is discussed. Using the existing results from Au + Au and pp collisions, the dependence of freeze-out parameters on the system size is also explored. This multidimensional systematic study furthers our understanding of the QCD phase diagram revealing the importance …

The Influence Of Pressure Relaxation On The Structure Of An Axial Vortex, Robert L. Ash, Irfan Zardadkhan, Allan J. Zuckerwar

Mechanical & Aerospace Engineering Faculty Publications

Governing equations including the effects of pressure relaxation have been utilized to study an incompressible, steady-state viscous axial vortex with specified far-field circulation. When sound generation is attributed to a velocity gradient tensor-pressure gradient product, the modified conservation of momentum equations that result yield an exact solution for a steady, incompressible axial vortex. The vortex velocity profile has been shown to closely approximate experimental vortex measurements in air and water over a wide range of circulation-based Reynolds numbers. The influence of temperature and humidity on the pressure relaxation coefficient in air has been examined using theoretical and empirical approaches, and …

A Cell Electrofusion Microfluidic Device Integrated With 3d Thin-Film Microelectrode Arrays, Ning Hu, Jun Yang, Shizhi Qian, Sang W. Joo, Xiaolin Zheng

Mechanical & Aerospace Engineering Faculty Publications

A microfluidic device integrated with 3D thin film microelectrode arrays wrapped around serpentine-shaped microchannel walls has been designed, fabricated and tested for cell electrofusion. Each microelectrode array has 1015 discrete microelectrodes patterned on each side wall, and the adjacent microelectrodes are separated by coplanar dielectric channel wall. The device was tested to electrofuse K562 cells under a relatively low voltage. Under an AC electric field applied between the pair of the microelectrode arrays, cells are paired at the edge of each discrete microelectrode due to the induced positive dielectrophoresis. Subsequently, electric pulse signals are sequentially applied between the microelectrode arrays …

Drag Reduction Of A Modern Straight Truck, Drew Landman, Matthew Cragun, Mike Mccormick, Richard Wood

Mechanical & Aerospace Engineering Faculty Publications

A wind tunnel test program was conducted at the Langley Full Scale Tunnel (LFST) to evaluate the performance of five passive drag reduction configurations on a modern straight truck at full scale. Configurations were tested in a build-up fashion with results representing a cumulative effect. Tested configurations include a front valance, a front box fairing, a boat-tail, an ideal side-skirt, and a practical side-skirt. Configurations were evaluated over a nominal 9 degree yaw sweep to establish wind averaged drag coefficients using SAE J1252. Genuine replicate yaw sweeps were used in an uncertainty analysis. Results show up to 28% improvement in …

An Integrated Computer-Aided Robotic System For Dental Implantation, Xiaoyan Sun, Yongki Yoon, Jiang Li, Frederic D. Mckenzie

Electrical & Computer Engineering Faculty Publications

This paper describes an integrated system for dental implantation including both preoperative planning utilizing computer-aided technology and automatic robot operation during the intra-operative stage. A novel two-step registration procedure was applied for transforming the preoperative plan to the operation of the robot, with the help of a Coordinate Measurement Machine (CMM). Experiments with a patient-specific phantom were carried out to evaluate the registration error for both position and orientation. After adopting several improvements, registration accuracy of the system was significantly improved. Sub-millimeter accuracy with the Target Registration Errors (TREs) of 0.38±0.16 mm (N=5) was achieved. The target orientation errors after …

Bcc Skin Cancer Diagnosis Based On Texture Analysis Techniques, Shao-Hui Chuang, Xiaoyan Sun, Wen-Yu Chang, Gwo-Shing Chen, Adam Huang, Jiang Li, Frederic D. Mckenzie

Electrical & Computer Engineering Faculty Publications

In this paper, we present a texture analysis based method for diagnosing the Basal Cell Carcinoma (BCC) skin cancer using optical images taken from the suspicious skin regions. We first extracted the Run Length Matrix and Haralick texture features from the images and used a feature selection algorithm to identify the most effective feature set for the diagnosis. We then utilized a Multi-Layer Perceptron (MLP) classifier to classify the images to BCC or normal cases. Experiments showed that detecting BCC cancer based on optical images is feasible. The best sensitivity and specificity we achieved on our data set were 94% …

Automatic Detection Of Aircraft Emergency Landing Sites, Yu-Fei Shen, Zia-Ur Rahman, Dean Krusienski, Jiang Li, Zia-Ur Rahman (Ed.), Stephen E. Reichenbach (Ed.), Mark Allen Neifeld (Ed.)

Electrical & Computer Engineering Faculty Publications

An automatic landing site detection algorithm is proposed for aircraft emergency landing. Emergency landing is an unplanned event in response to emergency situations. If, as is unfortunately usually the case, there is no airstrip or airfield that can be reached by the un-powered aircraft, a crash landing or ditching has to be carried out. Identifying a safe landing site is critical to the survival of passengers and crew. Conventionally, the pilot chooses the landing site visually by looking at the terrain through the cockpit. The success of this vital decision greatly depends on the external environmental factors that can impair …

3d Face Reconstruction From Limited Images Based On Differential Evolution, Qun Wang, Jiang Li, Vijayan K. Asari, Mohammad A. Karim, Andrew G. Tescher (Ed.)

Electrical & Computer Engineering Faculty Publications

3D face modeling has been one of the greatest challenges for researchers in computer graphics for many years. Various methods have been used to model the shape and texture of faces under varying illumination and pose conditions from a single given image. In this paper, we propose a novel method for the 3D face synthesis and reconstruction by using a simple and efficient global optimizer. A 3D-2D matching algorithm which employs the integration of the 3D morphable model (3DMM) and the differential evolution (DE) algorithm is addressed. In 3DMM, the estimation process of fitting shape and texture information into 2D …

Enhancement Technique For Aerial Images, Sertan Erkanli, Ahmet Gungor Pakfiliz, Jiang Li

Electrical & Computer Engineering Faculty Publications

Recently, we proposed an enhancement technique for uniformly and non-uniformly illuminated dark images that provides high color accuracy and better balance between the luminance and the contrast in images to improve the visual representations of digital images. In this paper we define an improved version of the proposed algorithm to enhance aerial images in order to reduce the gap between direct observation of a scene and its recorded image.

Ignition Of A Large Volume Plasma With A Plasma Jet, M. Laroussi, M. A. Akman

Electrical & Computer Engineering Faculty Publications

Here we report on a method to generate a long plasma plume and to ignite a large volume plasma by means of the jet. The plasma plume is generated by our tube reactor and then introduced into a chamber where the pressure is controlled. We discovered there are three operating phases:Aphasewhere the plume length remains approximately constant, followed by a second phase where the jet increases in length as the pressure decreases. Then at pressures below 70 Torr a mode transition occurs where the plume length decreases and the plasma expands until the entire chamber is filled.

Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler

Electrical & Computer Engineering Faculty Publications

The time evolution of the ground state wave function of a zero-temperature Bose-Einstein condensate (BEC) gas is well described by the Hamiltonian Gross-Pitaevskii (GP) equation. Using a set of appropriately interleaved unitary collision-stream operators, a qubit lattice gas algorithm is devised, which on taking moments, recovers the Gross-Pitaevskii (GP) equation under diffusion ordering (time scales as length²). Unexpectedly, there is a class of initial states whose Poincaré recurrence time is extremely short and which, as the grid resolution is increased, scales with diffusion ordering (and not as length³). The spectral results of J. Yepez et al. …

Precise Control Of Highly Ordered Arrays Of Nested Semiconductor/Metal Nanotubes, Diefeng Gu, Helmut Baumgart, Kandabara Tapily, Pragya Shrestha, Gon Namkoong, Xianyu Ao, Frank Müller

Electrical & Computer Engineering Faculty Publications

Lithographically defined microporous templates in conjunction with the atomic layer deposition (ALD) technique enable remarkable control of complex novel nested nanotube structures. So far three-dimensional control of physical process parameters has not been fully realized with high precision resolution, and requires optimization in order to achieve a wider range of potential applications. Furthermore, the combination of composite insulating oxide layers alternating with semiconducting layers and metals can provide various types of novel applications and eventually provide unique and advanced levels of multifunctional nanoscale devices. Semiconducting TiO₂ nanotubes have potential applications in photovoltaic devices. The combination of nanostructured semiconducting materials …

Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) with different shapes and disk-shaped Ag NP pairs with varying interparticle distance is studied using dark-field optical microscopy and spectroscopy (DFOMS). Disk-, square-, and triangular-shaped Ag NPs were fabricated on indium tin oxide-coated glass substrates by electron beam lithography. The LSPR spectra collected from single Ag NPs within 5×5 arrays using DFOMS exhibited pronounced redshifts as the NP shape changed from disk to square and to triangular. The shape-dependent experimental LSPR spectra are in good agreement with simulations using the discrete dipole approximation model, although there are small deviations in the …

Low Temperature Epitaxial Growth Of Ge Quantum Dot On Si (100) - (2×1) By Femtosecond Laser Excitation, Ali Oguz Er, Wei Ren, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Low temperature epitaxy of Ge quantum dots on Si (100) - (2×1) by femtosecond pulsed laser deposition under femtosecond laser excitation was investigated. Reflection high-energy electron diffraction and atomic force microscopy were used to analyze the growth mode and morphology. Epitaxial growth was achieved at ∼70 °C by using femtosecond laser excitation of the substrate. A purely electronic mechanism of enhanced surface diffusion of the Ge adatoms is proposed. © 2011 American Institute of Physics. [doi:10.1063/1.3537813]

Nonuniformity In Lattice Contraction Of Bismuth Nanoclusters Heated Near Its Melting Point, A. Esmail, M. Abdel-Fattah, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The structural properties of bismuth nanoclusters were investigated with transmission high-energy electron diffraction from room temperature up to 525 ± 6 K. The Bi nanoclusters were fabricated by thermal evaporation at room temperature on transmission electron microscope grids coated with an ultrathin carbon film, followed by thermal and femtosecond laser annealing. The annealed sample had an average cluster size of ∼14 nm along the minor axis and ∼16 nm along the major axis. The Debye temperature of the annealed nanoclusters was found to be 53 ± 6 K along the [012] direction and 86 ± 9 K along the [110] …

Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin

Electrical & Computer Engineering Faculty Publications

We propose coupled cavities to realize a strong enhancement of the Raman scattering. Five sub cavities are embedded in the photonic crystals. Simulations through finite-difference time-domain (FDTD) method demonstrate that one cavity, which is used to propagate the pump beam at the optical-communication wavelength, has a Q factor as high as 1.254 × 10⁸ and modal volume as small as 0.03μm³ (0.3192(λ/n)³). These parameters result in ultra-small threshold lasing power ~17.7nW and 2.58nW for Stokes and anti-Stokes respectively. The cavities are designed to support the required Stokes and anti-Stokes modal spacing in silicon. The proposed structure …

Imbalanced Learning For Functional State Assessment, Feng Li, Frederick Mckenzie, Jiang Li, Guanfan Zhang, Roger Xu, Carl Richey, Tom Schnell, Thomas E. Pinelli (Ed.)

Electrical & Computer Engineering Faculty Publications

This paper presents results of several imbalanced learning techniques applied to operator functional state assessment where the data is highly imbalanced, i.e., some function states (majority classes) have much more training samples than other states (minority classes). Conventional machine learning techniques usually tend to classify all data samples into majority classis and perform poorly for minority classes. In this study, we implemented five imbalanced learning techniques, including random under-sampling, random over-sampling, synthetic minority over-sampling technique (SMOTE), borderline-SMOTE and adaptive synthetic sampling (ADASYN) to solve this problem. Experimental results on a benchmark driving test dataset show that accuracies for minority classes …

Eeg Artifact Removal Using A Wavelet Neural Network, Hoang-Anh T. Nguyen, John Musson, Jiang Li, Frederick Mckenzie, Guangfan Zhang, Roger Xu, Carl Richey, Tom Schnell, Thomas E. Pinelli (Ed.)

Electrical & Computer Engineering Faculty Publications

In this paper we developed a wavelet neural network. (WNN) algorithm for Electroencephalogram (EEG) artifact removal without electrooculographic (EOG) recordings. The algorithm combines the universal approximation characteristics of neural network and the time/frequency property of wavelet. We compared the WNN algorithm with the ICA technique and a wavelet thresholding method, which was realized by using the Stein's unbiased risk estimate (SURE) with an adaptive gradient-based optimal threshold. Experimental results on a driving test data set show that WNN can remove EEG artifacts effectively without diminishing useful EEG information even for very noisy data.

Prediction Of Brain Tumor Progression Using Multiple Histogram Matched Mri Scans, Debrup Banerjee, Loc Tran, Jiang Li, Yuzhong Shen, Frederic Mckenzie, Jihong Wang, Ronald M. Summers (Ed.), Bram Van Ginneken (Ed.)

Electrical & Computer Engineering Faculty Publications

In a recent study [1], we investigated the feasibility of predicting brain tumor progression based on multiple MRI series and we tested our methods on seven patients' MRI images scanned at three consecutive visits A, B and C. Experimental results showed that it is feasible to predict tumor progression from visit A to visit C using a model trained by the information from visit A to visit B. However, the trained model failed when we tried to predict tumor progression from visit B to visit C, though it is clinically more important. Upon a closer look at the MRI scans …

2d Face Database Diversification Based On 3d Face Modeling, Qun Wang, Jiang Li, Vijayan K. Asari, Mohammad A. Karim, Manuel Filipe Costa (Ed.)

Electrical & Computer Engineering Faculty Publications

Pose and illumination are identified as major problems in 2D face recognition (FR). It has been theoretically proven that the more diversified instances in the training phase, the more accurate and adaptable the FR system appears to be. Based on this common awareness, researchers have developed a large number of photographic face databases to meet the demand for data training purposes. In this paper, we propose a novel scheme for 2D face database diversification based on 3D face modeling and computer graphics techniques, which supplies augmented variances of pose and illumination. Based on the existing samples from identical individuals of …

Special Issue On Information Dissemination And New Services In P2p Systems, Min Song, Sachin Shetty, Wenbin Jiang, E. K. Park

Electrical & Computer Engineering Faculty Publications

Information dissemination is an important P2P application that has received considerable research attention in recent years. P2P information dissemination systems range from simple file sharing applications to more complex systems that allows users to securely and efficiently publish, organize, index, search, update and retrieve data in a distributed storage medium. For complex P2P information dissemination systems, there is a need for features which include security, anonymity, fairness, scalability, resource management, and organization capabilities. For effective information dissemination, following features of P2P systems and infrastructure need to be updated: distributed object location and routing mechanisms, novel approaches to content replication, caching …

Histogram Analysis Of Adc In Brain Tumor Patients, Debrup Banerjee, Jihong Wang, Jiang Li, Norbert J. Pelc (Ed.), Ehsan Samei (Ed.), Robert M. Nishikawa (Ed.)

Electrical & Computer Engineering Faculty Publications

At various stage of progression, most brain tumors are not homogenous. In this presentation, we retrospectively studied the distribution of ADC values inside tumor volume during the course of tumor treatment and progression for a selective group of patients who underwent an anti-VEGF trial. Complete MRI studies were obtained for this selected group of patients including pre- and multiple follow-up, post-treatment imaging studies. In each MRI imaging study, multiple scan series were obtained as a standard protocol which includes T1, T2, T1-post contrast, FLAIR and DTI derived images (ADC, FA etc.) for each visit. All scan series (T1, T2, FLAIR, …

Marine Buoy Detection Using Circular Hough Transform, Loc Tran, Justin Selfridge, Gene Hou, Jiang Li

Electrical & Computer Engineering Faculty Publications

A low cost method for buoy detection in maritime settings is presented using inexpensive digital cameras. In this method, the circular Hough transform is applied to an edge image to circular objects in the image. The center of these circles will signify the locations of each buoy. The known color information of the buoys is also used to enhance the performance by removing false detections. The algorithm is compared to an approach that locates buoys purely on color information. In order to validate the method, we test the approach synthetically and also with real images captured from a small surface …