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2019

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Articles 511 - 534 of 534

Full-Text Articles in Engineering

Investigation Into Photovoltaic Distributed Generation Penetration In The Low Voltage Distribution Network, Shivananda Pukhrem Jan 2019

Investigation Into Photovoltaic Distributed Generation Penetration In The Low Voltage Distribution Network, Shivananda Pukhrem

Doctoral

Significant integration of photovoltaic distributed generation (PVDG) in the low voltage distribution network (LVDN) could potentially pose threats and challenges to the core activity of distribution system operators (DSO), which is to transport electrical energy in a reliable and cost-effective way. The main aim of this research is to investigate the active planning and operation of LVDNs with increased PVDG integration through steady state power system analysis. To address the impacts of voltage profile fluctuation due to power flow modification, this research proposes a probabilistic risk assessment of power quality (PQ) variations and events that may arise due to significant …


Phase Resolved Partial Discharge Evaluation At Dc Voltage, Tobias Dezenzo Jan 2019

Phase Resolved Partial Discharge Evaluation At Dc Voltage, Tobias Dezenzo

Doctoral

Partial discharge diagnostics are common for the condition assessment of high voltage alternating current (ac) and direct current (dc) equipment. For ac applications the phase resolved partial discharge evaluation method has prevailed [1]. Even though, numerous methods for dc partial discharge diagnostics have been proposed no agreed standard exists. This is primarily because of the fact that these methods are not as easily applicable as the well-known, intuitive, pattern based phase resolved method. Due to the often assumed unavailability of a useable phase angle information [2]–[4] this method has never been transferred to dc partial discharge diagnostics. However, as a …


Unique Constant Phase Element Behavior Of The Electrolyte–Graphene Interface, Jianbo Sun, Yuxin Liu Jan 2019

Unique Constant Phase Element Behavior Of The Electrolyte–Graphene Interface, Jianbo Sun, Yuxin Liu

Faculty & Staff Scholarship

We report a unique constant phase element (CPE) behavior ( 1Z=Q0(jω)α" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; font-size: 14.3px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">1Z=Q0(jω)α ) of the electrolyte–graphene interface with both Q0" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; font-size: 14.3px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">Q0 and α" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; …


Real-Time Path Planning In Constrained, Uncertain Environments, Randall Christensen, Robert C. Leishman Jan 2019

Real-Time Path Planning In Constrained, Uncertain Environments, Randall Christensen, Robert C. Leishman

Faculty Publications

A key enabler of autonomous vehicles is the ability to plan the path of the vehicle to accomplish mission objectives. To be robust to realistic environments, path planners must account for uncertainty in the trajectory of the vehicle as well as uncertainty in the location of obstacles. The uncertainty in the trajectory of the vehicle is a difficult quantity to estimate, and is influenced by coupling between the vehicle dynamics, guidance, navigation, and control system as well as any disturbances acting on the vehicle. Monte Carlo analysis is the conventional approach to determine vehicle dispersion, while accounting for the coupled …


A High Torque Density Halbach Rotor Coaxial Magnetic Gear, Ho Yin Wong, Jonathan Z. Bird, David Barnett, Wesley Williams Jan 2019

A High Torque Density Halbach Rotor Coaxial Magnetic Gear, Ho Yin Wong, Jonathan Z. Bird, David Barnett, Wesley Williams

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents the design, analysis, and experimental testing results for a 5.67:1 Halbach rotor magnetic gearbox with a ferromagnetic back support. Using 3-D finite element analysis software the Halbach magnetic gearbox was calculated to achieve a volumetric torque density of 284N·m/L with only an active region outer diameter of 120mm. The experimental prototype obtained an active region volumetric torque density of 261.4N·m/L


Quantifying The Concentration And Penetration Depth Of Long-Lived Rons In Plasma Activated Water By Uv Absorption Spectroscopy, Zhijie Liu, Chunxi Zhou, Dingxin Liu, Tongtong He, Li Guo, Dehui Xu, Michael G. Kong Jan 2019

Quantifying The Concentration And Penetration Depth Of Long-Lived Rons In Plasma Activated Water By Uv Absorption Spectroscopy, Zhijie Liu, Chunxi Zhou, Dingxin Liu, Tongtong He, Li Guo, Dehui Xu, Michael G. Kong

Bioelectrics Publications

Reactive oxygen and reactive nitrogen species (RONS) are believed to play a key role in biomedical applications, which means that RONS must reach the target tissue to produce a therapeutic effect. Existing methods (electron spin spectrometry and microplate reading) to determine the RONS concentration are not suitable for experimental real-time measurements because they require adding an indicating reagent to the plasma-treated medium, which may alter the chemical composition of the medium. In this paper, we propose a method to measure the long-lived RONS concentration in plasma-activated water (PAW) by using UV absorption spectroscopy. Based on an analysis and fit of …


Selective Distant Electrostimulation By Synchronized Bipolar Nanosecond Pulses, Elena C. Gianulis, Maura Casciola, Carol Zhou, Enbo Yang, Shu Xiao, Andrei G. Pakhomov Jan 2019

Selective Distant Electrostimulation By Synchronized Bipolar Nanosecond Pulses, Elena C. Gianulis, Maura Casciola, Carol Zhou, Enbo Yang, Shu Xiao, Andrei G. Pakhomov

Bioelectrics Publications

A unique aspect of electrostimulation (ES) with nanosecond electric pulses (nsEP) is the inhibition of effects when the polarity is reversed. This bipolar cancellation feature makes bipolar nsEP less efficient at biostimulation than unipolar nsEP. We propose to minimize stimulation near pulse-delivering electrodes by applying bipolar nsEP, whereas the superposition of two phase-shifted bipolar nsEP from two independent sources yields a biologically-effective unipolar pulse remotely. This is accomplished by electrical compensation of all nsEP phases except the first one, resulting in the restoration of stimulation efficiency due to cancellation of bipolar cancellation (CANCAN-ES). We experimentally proved the CANCAN-ES paradigm by …


Nanosecond Pulsed Electric Fields Induce Endoplasmic Reticulum Stress Accompanied By Immunogenic Cell Death In Murine Models Of Lymphoma And Colorectal Cancer, Alessandra Rossi, Olga N. Pakhomova, Peter A. Mollica, Maura Casciola, Uma Mangalanathan, Andrei G. Pakhomov, Claudia Muratori Jan 2019

Nanosecond Pulsed Electric Fields Induce Endoplasmic Reticulum Stress Accompanied By Immunogenic Cell Death In Murine Models Of Lymphoma And Colorectal Cancer, Alessandra Rossi, Olga N. Pakhomova, Peter A. Mollica, Maura Casciola, Uma Mangalanathan, Andrei G. Pakhomov, Claudia Muratori

Bioelectrics Publications

Depending on the initiating stimulus, cancer cell death can be immunogenic or non-immunogenic. Inducers of immunogenic cell death (ICD) rely on endoplasmic reticulum (ER) stress for the trafficking of danger signals such as calreticulin (CRT) and ATP. We found that nanosecond pulsed electric fields (nsPEF), an emerging new modality for tumor ablation, cause the activation of the ER-resident stress sensor PERK in both CT-26 colon carcinoma and EL-4 lymphoma cells. PERK activation correlates with sustained CRT exposure on the cell plasma membrane and apoptosis induction in both nsPEF-treated cell lines. Our results show that, in CT-26 cells, the activity of …


Mechanisms And Immunogenicity Of Nspef-Induced Cell Death In B16f10 Melanoma Tumors, Alessandra Rossi, Olga N. Pakhomova, Andrei G. Pakhomov, Samantha Weygandt, Anna A. Bulysheva, Len E. Murray, Peter A. Mollica, Claudia Muratori Jan 2019

Mechanisms And Immunogenicity Of Nspef-Induced Cell Death In B16f10 Melanoma Tumors, Alessandra Rossi, Olga N. Pakhomova, Andrei G. Pakhomov, Samantha Weygandt, Anna A. Bulysheva, Len E. Murray, Peter A. Mollica, Claudia Muratori

Bioelectrics Publications

Accumulating data indicates that some cancer treatments can restore anticancer immunosurveillance through the induction of tumor immunogenic cell death (ICD). Nanosecond pulsed electric fields (nsPEF) have been shown to efficiently ablate melanoma tumors. In this study we investigated the mechanisms and immunogenicity of nsPEF-induced cell death in B16F10 melanoma tumors. Our data show that in vitro nsPEF (20-200, 200-ns pulses, 7 kV/cm, 2 Hz) caused a rapid dose-dependent cell death which was not accompanied by caspase activation or PARP cleavage. The lack of nsPEF-induced apoptosis was confirmed in vivo in B16F10 tumors. NsPEF also failed to trigger ICD-linked responses such …


Eece 7215/8215: Digital Signal Processing (Syllabus), Madhusudhanan Balasubramanian Jan 2019

Eece 7215/8215: Digital Signal Processing (Syllabus), Madhusudhanan Balasubramanian

Electrical and Computer Engineering Syllabi

Course Description: Application of discrete transform theory to spectral analysis, digital filters, random signal analysis.


Compact -300 Kv Dc Inverted Insulator Photogun With Biased Anode And Alkali-Antimonide Photocathode, C. Hernandez-Garcia, P. Adderley, B. Bullard, J. Benesch, J. Grames, J. Gubeli, F. Hannon, J. Hansknecht, J. Jordan, R. Kazimi, G. A. Krafft, M. A. Mamun, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, Y. Wang, S. Zhang, H. Baumgart, G. Palacios-Serrano, S. Wijethunga, J. Yoskowitz, C. A. Valerio Lizarraga, R. Montoya Soto, A. Canales Ramos Jan 2019

Compact -300 Kv Dc Inverted Insulator Photogun With Biased Anode And Alkali-Antimonide Photocathode, C. Hernandez-Garcia, P. Adderley, B. Bullard, J. Benesch, J. Grames, J. Gubeli, F. Hannon, J. Hansknecht, J. Jordan, R. Kazimi, G. A. Krafft, M. A. Mamun, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, Y. Wang, S. Zhang, H. Baumgart, G. Palacios-Serrano, S. Wijethunga, J. Yoskowitz, C. A. Valerio Lizarraga, R. Montoya Soto, A. Canales Ramos

Electrical & Computer Engineering Faculty Publications

This contribution describes the latest milestones of a multiyear program to build and operate a compact −300  kV dc high voltage photogun with inverted insulator geometry and alkali-antimonide photocathodes. Photocathode thermal emittance measurements and quantum efficiency charge lifetime measurements at average current up to 4.5 mA are presented, as well as an innovative implementation of ion generation and tracking simulations to explain the benefits of a biased anode to repel beam line ions from the anode-cathode gap, to dramatically improve the operating lifetime of the photogun and eliminate the occurrence of micro-arc discharges.


Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji Jan 2019

Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji

Electrical & Computer Engineering Faculty Publications

Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg-1 at 2 mVs-1), higher surface capacitive contribution (75%), better stability and rate …


Initial Implementation Of A Machine Learning System For Srf Cavity Fault Classification At Cebaf, A. Carpenter, K. M. Iftekharuddin, T. Powers, Y. Roblin, A. Solopava Shabalina, C. Tennant, L. Vidyaratne Jan 2019

Initial Implementation Of A Machine Learning System For Srf Cavity Fault Classification At Cebaf, A. Carpenter, K. M. Iftekharuddin, T. Powers, Y. Roblin, A. Solopava Shabalina, C. Tennant, L. Vidyaratne

Electrical & Computer Engineering Faculty Publications

The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Laboratory is a high power Continuous Wave (CW) electron accelerator. It uses a mixture of of SRF cryomodules: older, lower energy C20/C50 modules and newer, higher energy C100 modules. The cryomodules are arrayed in two anti-parallel linear accelerators. Accurately classifying the type of cavity faults is essential to maintaining and improving accelerator performance. Each C100 cryomodule contains eight 7-cell cavities. When a cavity fault occurs within a cryomodule, all eight cavities generate 17 waveforms each containing 8192 points. This data is exported from the control system and saved for review. Analysis …


Special Issue On Low Temperature Plasma Jets, Mounir Laroussi Jan 2019

Special Issue On Low Temperature Plasma Jets, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

[Introduction] Low temperature plasma jets are unique plasma sources capable of delivering plasma outside of the confinement of electrodes and away from gas enclosures/chambers. With these jets plasma can be easily delivered to a target located at some distance from the plasma generation region [1].


N-I-P Nanocrystalline Hydrogenated Silicon Solar Cells With Rf-Magnetron Sputtered Absorbers, Dipendra Adhikari, Maxwell M. Junda, Corey R. Grice, Sylvain X. Marsillac, Robert W. Collins, Nikolas J. Podraza Jan 2019

N-I-P Nanocrystalline Hydrogenated Silicon Solar Cells With Rf-Magnetron Sputtered Absorbers, Dipendra Adhikari, Maxwell M. Junda, Corey R. Grice, Sylvain X. Marsillac, Robert W. Collins, Nikolas J. Podraza

Electrical & Computer Engineering Faculty Publications

Nanocrystalline hydrogenated silicon (nc-Si:H) substrate configuration n-i-p solar cells have been fabricated on soda lime glass substrates with active absorber layers prepared by plasma enhanced chemical vapor deposition (PECVD) and radio frequency magnetron sputtering. The cells with nanocrystalline PECVD absorbers and an untextured back reflector serve as a baseline for comparison and have power conversion efficiency near 6%. By comparison, cells with sputtered absorbers achieved efficiencies of about 1%. Simulations of external quantum efficiency (EQE) are compared to experimental EQE to determine a carrier collection probability gradient with depth for the device with the sputtered i-layer absorber. This incomplete …


Ultrafast Time-Resolved Structural Changes Of Thin-Film Ferromagnetic Metal Heated With Femtosecond Optical Pulses, Runze Li, Hani Elsayed-Ali, Jie Chen, Dinesh Dhankhar, Arjun Krishnamoorthi, Peter M. Rentzepis Jan 2019

Ultrafast Time-Resolved Structural Changes Of Thin-Film Ferromagnetic Metal Heated With Femtosecond Optical Pulses, Runze Li, Hani Elsayed-Ali, Jie Chen, Dinesh Dhankhar, Arjun Krishnamoorthi, Peter M. Rentzepis

Electrical & Computer Engineering Faculty Publications

As a classic ferromagnetic material, nickel has been an important research candidate used to study dynamics and interactions of electron, spin, and lattice degrees of freedom. In this study, we specifically chose a thick, 150 nm ferromagnetic nickel (111) single crystal rather than 10–20 nm thin crystals that are typically used in ultrafast studies, and we revealed both the ultrafast heating within the skin depth and the heat transfer from the surface (skin) layer to the bulk of the crystal. The lattice deformation after femtosecond laser excitation was investigated by means of 8.04 keV subpicosecond x-ray pulses, generated from a …


Glioma Grading Using Structural Magnetic Resonance Imaging And Molecular Data, Syed M.S. Reza, Manar D. Samad, Zeina A. Shboul, Karra A. Jones, Khan M. Iftekharuddin Jan 2019

Glioma Grading Using Structural Magnetic Resonance Imaging And Molecular Data, Syed M.S. Reza, Manar D. Samad, Zeina A. Shboul, Karra A. Jones, Khan M. Iftekharuddin

Electrical & Computer Engineering Faculty Publications

A glioma grading method using conventional structural magnetic resonance image (MRI) and molecular data from patients is proposed. The noninvasive grading of glioma tumors is obtained using multiple radiomic texture features including dynamic texture analysis, multifractal detrended fluctuation analysis, and multiresolution fractal Brownian motion in structural MRI. The proposed method is evaluated using two multicenter MRI datasets: (1) the brain tumor segmentation (BRATS-2017) challenge for high-grade versus low-grade (LG) and (2) the cancer imaging archive (TCIA) repository for glioblastoma (GBM) versus LG glioma grading. The grading performance using MRI is compared with that of digital pathology (DP) images in the …


Microstructural Evaluation Of Aluminium Alloy A365 T6 In Machining Operation, Bankole I. Oladapo, S. Abolfazl Zahedi, Francis T. Omigbodun, Edwin A. Oshin, Victor A. Adebiyi, Olaoluwa B. Malachi Jan 2019

Microstructural Evaluation Of Aluminium Alloy A365 T6 In Machining Operation, Bankole I. Oladapo, S. Abolfazl Zahedi, Francis T. Omigbodun, Edwin A. Oshin, Victor A. Adebiyi, Olaoluwa B. Malachi

Electrical & Computer Engineering Faculty Publications

The optimum cutting parameters such as cutting depth, feed rate, cutting speed and magnitude of the cutting force for A356 T6 was determined concerning the microstructural detail of the material. Novel test analyses were carried out, which include mechanical evaluation of the materials for density, glass transition temperature, tensile and compression stress, frequency analysis and optimisation as well as the functional analytic behaviour of the samples. The further analytical structure of the particle was performed, evaluating the surface luminance structure and the profile structure. The cross-sectional filter profile of the sample was extracted, and analyses of Firestone curve for the …


Carbon Multicharged Ion Generation From Laser-Spark Ion Source, Md. Mahmudur Rahman, Oguzhan Balki, Hani E. Elsayed-Ali Jan 2019

Carbon Multicharged Ion Generation From Laser-Spark Ion Source, Md. Mahmudur Rahman, Oguzhan Balki, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Multicharged carbon ions are generated by using a laser-assisted spark-discharge ion source. A Q-switched Nd:YAG laser pulse (1064 nm, 7 ns, ≤ 4.5 × 109 W/cm2) focused onto the surface of a glassy carbon target results in its ablation. The spark-discharge (∼1.2 J energy, ∼1 µs duration) is initiated along the direction of the plume propagation between the target surface and a grounded mesh that is parallel to the target surface. Ions emitted from the laser-spark plasma are detected by their time-of-flight using a Faraday cup. The ion energy-to-charge ratio is analyzed by a three-mesh retarding field …


Detecting Special-Cause Variation 'Events' From Process Data Signatures, Timothy M. Young, Olga Khaliukova, Nicolas André, Alexander Petutschnigg, Timothy G. Rials, Chung-Hao Chen Jan 2019

Detecting Special-Cause Variation 'Events' From Process Data Signatures, Timothy M. Young, Olga Khaliukova, Nicolas André, Alexander Petutschnigg, Timothy G. Rials, Chung-Hao Chen

Electrical & Computer Engineering Faculty Publications

The ability to detect the special-cause variation of incoming feedstocks from advanced sensor technology is invaluable to manufacturers. Many on-line sensors produce data signatures that require further off-line statistical processing for interpretation by operational personnel. However, early detection of changes in variation in incoming feedstocks may be imperative to promote early-stage preventive measures. A method is proposed in this applied study for developing control bands to quantify the variation of data signatures in the context of statistical process control (SPC). Control bands based on pointwise prediction intervals constructed from the Bonferroni Inequality and Bayesian smoothing splines are developed. Applications using …


Ignition Of A Plasma Discharge Inside An Electrodeless Chamber: Methods And Characteristics, Mounir Laroussi Jan 2019

Ignition Of A Plasma Discharge Inside An Electrodeless Chamber: Methods And Characteristics, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

In this paper the generation and diagnostics of a reduced pressure (300 mTorr to 3 Torr) plasma generated inside an electrodeless containment vessel/chamber are presented. The plasma is ignited by a guided ionization wave emitted by a low temperature pulsed plasma jet. The diagnostics techniques include Intensified Charge Coupled Device (ICCD) imaging, emission spectroscopy, and Langmuir probe. The reduced-pressure discharge parameters measured are the magnitude of the electric field, the plasma electron number density and temperature, and discharge expansion speed.


1995-2005: A Decade Of Innovation In Low Temperature Plasma And Its Applications, Mounir Laroussi Jan 2019

1995-2005: A Decade Of Innovation In Low Temperature Plasma And Its Applications, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

Scientific breakthroughs tend to come in spurts when unique societal, economical, and political circumstances conspire (knowingly or unknowingly) and create an environment ripe for creativity. The field of low temperature plasma (LTP) recently experienced such an upheaval, which this paper attempts to relate in some details. There have been “roadmap” papers published before, which look towards the future of the field, but all roads start somewhere and even “new” roads are often paved over older roads that were discovered and traveled by early pioneers. With the sharp decrease in funding for fusion research in the USA in the early 1990s …


A Compact Single-Element Pattern Reconfigurable Antenna With Wide-Angle Scanning Tuned By A Single Varactor, Haozhan Tian, Lijun Jiang, Tatsuo Itoh Jan 2019

A Compact Single-Element Pattern Reconfigurable Antenna With Wide-Angle Scanning Tuned By A Single Varactor, Haozhan Tian, Lijun Jiang, Tatsuo Itoh

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we propose a convenient fixed-frequency beam steering method, using a single patch antenna controlled by only one electronically tunable component. The antenna is based on coupled-mode patch antenna (CMPA) [1] that is capable to scan the beam as the function of frequency. A ground-etched slot loaded with one varactor diode is tuned to be capacitive, resonant, or inductive. In order to test broader tuning range, two kinds of varactors with the ranges of 9.24 pF-1.77 pF and 2.67 pF-0.63 pF are implemented respectively. By analyzing how the loaded slot affects the cavity modes and fields, we demonstrate …


Machine-Learning-Based Pml For The Fdtd Method, He Ming Yao, Lijun Jiang Jan 2019

Machine-Learning-Based Pml For The Fdtd Method, He Ming Yao, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

In this letter, a novel absorbing boundary condition (ABC) computation method for finite-difference time-domain (FDTD) is proposed based on the machine learning approach. The hyperbolic tangent basis function (HTBF) neural network is introduced to replace traditional perfectly matched layer (PML) ABC during the FDTD solving process. The field data on the interface of conventional PML are employed to train HTBF-based PML model. Compared to the conventional approach, the novel method greatly decreases the size of a computation domain and the computation complexity of FDTD because the new model only involves the one-cell boundary layer. Numerical examples are provided to benchmark …