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Full-Text Articles in Engineering

An Epileptic Seizure Detection Method From Eeg Signals Based On A Classifier-Driven Feature Reduction Technique, Raymond N. Kamel Jan 2023

An Epileptic Seizure Detection Method From Eeg Signals Based On A Classifier-Driven Feature Reduction Technique, Raymond N. Kamel

Theses and Dissertations

Epileptic seizure detection can improve the quality of life of epileptic patients, allow for more accurate medication, and minimize the risk of sudden unexpected death in epilepsy (SUDEP). This thesis work aims to develop a robust and stable algorithm for epileptic seizure detection through the classification of EEG signals. To achieve this aim, a methodology is proposed to develop a classifier that can differentiate between the healthy (normal), interictal, and ictal states of EEG signals, while maximizing the classification accuracy and minimizing the computational redundancy. The main pillar upon which this methodology is designed is using a problem-specific classifier-driven feature …


A Novel Approach For Optimal Sizing Of Stand-Alone Solar Pv Systems With Power Quality Considerations, Aakash Hassan, Octavian Bass, Yasir M. Al-Abdeli, Martin Masek, Mohammad A. S. Masoum Jan 2023

A Novel Approach For Optimal Sizing Of Stand-Alone Solar Pv Systems With Power Quality Considerations, Aakash Hassan, Octavian Bass, Yasir M. Al-Abdeli, Martin Masek, Mohammad A. S. Masoum

Research outputs 2022 to 2026

Designing reliable and cost-effective solar PV systems with compliance to national and international power quality standards is critical for their economical, efficient, and safe operation. The conventional approaches currently being used to optimally size the solar PV systems generally ignore power quality criteria during the initial design phase. This paper fills this gap by presenting a novel Genetic Algorithm (GA) based strategy to design a stand-alone solar PV system featuring optimal system size with conformance to power quality standards. MATLAB/Simulink environment was used to develop a detailed model of solar PV system, including a robust control mechanism for maximum power …


Electromagnetic Theory And Applications, Nicholas Madamopoulos, George Kliros Jan 2023

Electromagnetic Theory And Applications, Nicholas Madamopoulos, George Kliros

Open Educational Resources

This book intends to provide both the fundamentals of Electromagnetics but also some practical applications of the concepts covered. Having taught electromagnetics for several years, the authors feel that many times the field of electromagnetics comes as “old” and often times students do not appreciate the concepts and their importance in everyday applications. The authors intend to accompany the EM concepts with life applications. Hence, students may see the direct impact of the knowledge they acquire through the study of the field of electromagnetics and better appreciate the field.


Recent Advances In Exploring Highly Active & Durable Pgm-Free Oxygen Reduction Catalysts, Yuan Li, Miao-Ying Chen, Bang-An Lu, Jia-Nan Zhang Jan 2023

Recent Advances In Exploring Highly Active & Durable Pgm-Free Oxygen Reduction Catalysts, Yuan Li, Miao-Ying Chen, Bang-An Lu, Jia-Nan Zhang

Journal of Electrochemistry

In order to reduce the considerable usage of expensive but scarce platinum at the cathode in proton exchange membrane fuel cells (PEMFCs), it is necessary to pursue alternatives to platinum. The most promising platinum group metal (PGM)-free catalysts for oxygen reduction reaction (ORR) are atomically dispersed, and nitrogen-coordinated metal site catalysts denoted as M-N-C (M = Fe, Co, or Mn, etc.). Over the last few decades, there have been great advances in these catalysts with high ORR activity and promising initial fuel cell performance approaching traditional Pt/C catalysts. However, the stability of these highly active Fe-N-C catalysts under practical fuel …


Electrochemical Oxidation Of Ethylene On Palladium Electrode, Wei-Xing Wu, Ying Wang Jan 2023

Electrochemical Oxidation Of Ethylene On Palladium Electrode, Wei-Xing Wu, Ying Wang

Journal of Electrochemistry

The electrochemical oxidation of C2H4 is attracting increasing attention due to its vast potential market. The current electrochemical methods rely on the use of redox mediators, which may produce corrosive intermediates, while direct oxidation is still limited by its low activity and selectivity. Herein, we conducted electrochemical studies to obtain mechanistic insights into the benchmark Pd catalyst. The generated Pd(II) could be the active site for C2H4 oxidation. By designing the pulse sequence, we found the ratio of strongly and weakly adsorbed C2H4 on Pd to be 0.3:1. The result we …


Supperlattice-Like Structure: Ordered Mass Transfer Endowing High Quality Output Of Fuel Cell, Jian Wang, Wen-Hui Xuan, Qian He, Jing-Xia Jiang, Yuan-Yuan Zhou, Yao Nie, Qiang Liao, Min-Hua Shao, Wei Ding, Zi-Dong Wei Jan 2023

Supperlattice-Like Structure: Ordered Mass Transfer Endowing High Quality Output Of Fuel Cell, Jian Wang, Wen-Hui Xuan, Qian He, Jing-Xia Jiang, Yuan-Yuan Zhou, Yao Nie, Qiang Liao, Min-Hua Shao, Wei Ding, Zi-Dong Wei

Journal of Electrochemistry

The current or voltage fluctuation in fuel cell operation is harmful to the fuel cell system and power application equipment. Here, we report a technique to eliminate such a fluctuation by the aid of new type of catalysts, superlattice-like mesoporous PtCo catalysts. The current fluctuation in fuel cells catalyzed by two invented catalysts are fixed at as low as 25 mA·cm−2 with a power of 0.75 W·cm−2 or 120 mA·cm−2 with a power of 1.01 W·cm−2, and no noticeable current decay was detected over 100 h. By contrast, a …


Preface To Special Issue: Electrocatalysis And Electrosynthesis, Fang-Yi Cheng, Shuang-Yin Wang, Tian-Hua Zhou Jan 2023

Preface To Special Issue: Electrocatalysis And Electrosynthesis, Fang-Yi Cheng, Shuang-Yin Wang, Tian-Hua Zhou

Journal of Electrochemistry

No abstract provided.


The Visualization Of Orphadata Neurology Phenotypes, Daniel B. Hier, Raghu Yelugam, Michael D. Carrithers, Donald C. Wunsch Jan 2023

The Visualization Of Orphadata Neurology Phenotypes, Daniel B. Hier, Raghu Yelugam, Michael D. Carrithers, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Disease Phenotypes Are Characterized by Signs (What a Physician Observes during the Examination of a Patient) and Symptoms (The Complaints of a Patient to a Physician). Large Repositories of Disease Phenotypes Are Accessible through the Online Mendelian Inheritance of Man, Human Phenotype Ontology, and Orpha data Initiatives. Many of the Diseases in These Datasets Are Neurologic. for Each Repository, the Phenotype of Neurologic Disease is Represented as a List of Concepts of Variable Length Where the Concepts Are Selected from a Restricted Ontology. Visualizations of These Concept Lists Are Not Provided. We Address This Limitation by using Subsumption to Reduce …


Design Of A Non-Destructive System For Arctic Permafrost Detection Via High Frequency Electromagnetic Induction, Gray Dominic Thurston Jan 2023

Design Of A Non-Destructive System For Arctic Permafrost Detection Via High Frequency Electromagnetic Induction, Gray Dominic Thurston

Theses and Dissertations

Electromagnetic induction (EMI) sensors have been utilized in the past by the United States Army Corps of Engineers as a method of detecting unexploded ordnance (UXO). Recently, an EMI instrument was constructed that extended the traditional EMI frequency range from 100 kHz to 15 MHz to aid in the detection of nonmetallic ordnance, landmines, and improvised explosive devices. Building on this research, the iFROST mapper project aims to use the same high-frequency (HF) EMI technique to characterize arctic soil and subsurface permafrost deposits. Based on a device used by the US Army for UXO detection, an HF EMI instrument was …


Aiot-Based Smart Home Energy Management System, Mohammad Abdellatif, Ahmed K. Salama Jan 2023

Aiot-Based Smart Home Energy Management System, Mohammad Abdellatif, Ahmed K. Salama

Electrical Engineering

Artificial Intelligence of Things (AIoT) is a relatively new technology that combines Artificial Intelligence and Internet of Things. IoT devices can be integrated into large-scale systems for many modern applications. This results in a large amount of collected data, which needs efficient, and intelligent data processing for optimal use. Data can be processed and utilized for problem solving, decision making, and data prediction using AI. AI can increase the value of IoT, while IoT can improve AI's intel-ligence and learning. However, there are many obstacles to AIoT implementation such as complexity, precision, and efficiency. This study focuses on AI-powered IoT …


Senior Design Project - Ev Charger And Distributed Energy Resources, Eric Iliyev, Mostafa Younes, Abanoub Said, Carlos Figueroa, Ahmed Mohamed Jan 2023

Senior Design Project - Ev Charger And Distributed Energy Resources, Eric Iliyev, Mostafa Younes, Abanoub Said, Carlos Figueroa, Ahmed Mohamed

Open Educational Resources

No abstract provided.


Aircraft Communication Systems - Topologies, Protocols, And Vulnerabilities, Tyler Przybylski, Niroop Sugunaraj, Prakash Ranganathan Jan 2023

Aircraft Communication Systems - Topologies, Protocols, And Vulnerabilities, Tyler Przybylski, Niroop Sugunaraj, Prakash Ranganathan

Electrical Engineering Student Publications

Aviation systems are facing fierce competition driven by private investments promoting the development of new avionics suites (AS). With these new AS comes the need for a faster and larger bandwidth requirement for next generation communication systems. The legacy military (MIL) standard 1553 communication system (e.g., 1Mbps) can no longer keep up with the surge in bandwidth demand requirements. The new communication systems need to be designed with a system architecture background that can enable simplistic integration with Information Technology (IT) controlled groundnetworks, military, and commercial payloads. To facilitate a seamless integration with communication architecture, the current system is highly …


Data-Driven Nonparametric Joint Chance-Constrained Programming For Power Systems Scheduling, Chutian Wu Jan 2023

Data-Driven Nonparametric Joint Chance-Constrained Programming For Power Systems Scheduling, Chutian Wu

LSU Doctoral Dissertations

This dissertation is dedicated to implementing data-driven nonparametric joint chance constraints (JCC) to power system optimization problems. Power generated by renewable sources, such as solar farms, is an uncertain parameter. Several approaches solve optimization under uncertainty, including stochastic programming, robust programming, and chance-constrained programming. Uncertain parameters may not belong to any parametric class of probability functions. Thus, methods that consider such uncertainty as a random variable that fits in a known probability density function (PDF) have limitations. This study focuses on chance-constrained programming under nonparametric or data-driven distributionally robust uncertainty settings.

Studies based on chance-constrained programming usually focus on individual …


A Bilevel Game-Theoretic Decision-Making Framework For Strategic Retailers In Both Local And Wholesale Electricity Markets, Qiuyi Hong, Fanlin Meng, Jian Liu, Rui Bo Jan 2023

A Bilevel Game-Theoretic Decision-Making Framework For Strategic Retailers In Both Local And Wholesale Electricity Markets, Qiuyi Hong, Fanlin Meng, Jian Liu, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a bilevel game-theoretic model for multiple strategic retailers participating in both wholesale and local electricity markets while considering customers' switching behaviors. At the upper level, each retailer maximizes its own profit by making optimal pricing decisions in the retail market and bidding decisions in the day-ahead wholesale (DAW) and local power exchange (LPE) markets. The interaction among multiple strategic retailers is formulated using the Bertrand competition model. For the lower level, there are three optimization problems. First, the welfare maximization problem is formulated for customers to model their switching behaviors among different retailers. Second, a market-clearing problem …


Introduction To Control Engineering, Xiangyu Meng Jan 2023

Introduction To Control Engineering, Xiangyu Meng

E-Textbooks

This is an introductory level textbook for control engineering.


Subtypes Of Relapsing-Remitting Multiple Sclerosis Identified By Network Analysis, Quentin Howlett-Prieto, Chelsea Oommen, Michael D. Carrithers, Donald C. Wunsch, Daniel B. Hier Jan 2023

Subtypes Of Relapsing-Remitting Multiple Sclerosis Identified By Network Analysis, Quentin Howlett-Prieto, Chelsea Oommen, Michael D. Carrithers, Donald C. Wunsch, Daniel B. Hier

Electrical and Computer Engineering Faculty Research & Creative Works

We used network analysis to identify subtypes of relapsing-remitting multiple sclerosis subjects based on their cumulative signs and symptoms. The electronic medical records of 113 subjects with relapsing-remitting multiple sclerosis were reviewed, signs and symptoms were mapped to classes in a neuro-ontology, and classes were collapsed into sixteen superclasses by subsumption. After normalization and vectorization of the data, bipartite (subject-feature) and unipartite (subject-subject) network graphs were created using NetworkX and visualized in Gephi. Degree and weighted degree were calculated for each node. Graphs were partitioned into communities using the modularity score. Feature maps visualized differences in features by community. Network …


State Of The Art In Drivers’ Attention Monitoring – A Systematic Literature Review, Sama Hussein Al-Gburi, Kanar Alaa Al-Sammak, Ion Marghescu, Claudia Cristina Oprea Jan 2023

State Of The Art In Drivers’ Attention Monitoring – A Systematic Literature Review, Sama Hussein Al-Gburi, Kanar Alaa Al-Sammak, Ion Marghescu, Claudia Cristina Oprea

Karbala International Journal of Modern Science

Recently, driver inattention has become the leading cause of automobile accidents. As a result, the driver's perception and decision-making abilities are diminished, and the driver can lose control of the car. To prevent accidents caused by driver inattention, it’s vital to continuously monitor the driver and his driving behaviour and inform him if he becomes distracted or sleepy. This topic has been the subject of study for decades. Whenever feasible to recognise unsafe driving in advance, accidents could be avoided. This document presents an overview of the existing driver alertness system and the various techniques for detecting driver attentiveness.


Influence Of Synthesis Conditions On The Physicochemical And Electrocatalytic Properties Of Non-Stoichiometric Ba2sr2la2ti4o12 Perovskites, Ofeliya Kostadinova, Iliyan Popov, Simeon M. Stankov, Hristo Kolev, Tamara Petkov Jan 2023

Influence Of Synthesis Conditions On The Physicochemical And Electrocatalytic Properties Of Non-Stoichiometric Ba2sr2la2ti4o12 Perovskites, Ofeliya Kostadinova, Iliyan Popov, Simeon M. Stankov, Hristo Kolev, Tamara Petkov

Karbala International Journal of Modern Science

Present work studies the influence of the pretreatment milling media (deionized water (BLTOS-H) and isopropanol (BLTOS-i)) on the surface characteristics, structure, chemical composition and catalytic activity of non-stoichiometric Ba2Sr2La2Ti4O12 perovskites. The IR spectroscopy and XRD analyses shows a difference in the structure and phase composition of the two materials. X-ray photoelectron spectroscopy detects a Ba2+- and La3+-enriched and Sr2+-depleted surface. The BLTOS-i sample appears to exhibit higher specific surface area (SSA) and pore volume in comparison to BLTOS-H. The electrochemical tests showed that BLTOS-H sample have similar behavior to platinum at current densi-ties up to 10 mA cm-2, while BLTOS-i …


Using Dielectric Scatters To Selectively Excite Embedded Eigenstates In Cavity Resonators, Olugbenga Joshua Gbidi Jan 2023

Using Dielectric Scatters To Selectively Excite Embedded Eigenstates In Cavity Resonators, Olugbenga Joshua Gbidi

Theses and Dissertations

Bound states in the continuum (BICs) are waves that remain in the continuous spectrum of radiating waves that carry energy, however, still localized within the spectrum. BICs, also embedded eigenmodes, exhibit high quality factors that have been observed in optical and acoustic waveguides, photonic structures, and other material systems. Presently, there are limited means to select these BICs in terms of the quality factor and their excitation. In this work, we show that a different type of BIC, Quasi-BICs (Q-BICs), in open resonators can have their quality attuned by introducing embedded scatters. Using microwave cavities and dielectric scatters as an …


Perspectives On Design Considerations Inspired By Security And Quantum Technology In Cyberphysical Systems For Process Engineering, Helen Durand, Jihan Abou Halloun, Kip Nieman, Keshav Kasturi Rangan Jan 2023

Perspectives On Design Considerations Inspired By Security And Quantum Technology In Cyberphysical Systems For Process Engineering, Helen Durand, Jihan Abou Halloun, Kip Nieman, Keshav Kasturi Rangan

Chemical Engineering and Materials Science Faculty Research Publications

Advances in computer science have been a driving force for change in process systems engineering for decades. Faster computers, expanded computing resources, simulation software, and improved optimization algorithms have all changed chemical engineers’ abilities to predict, control, and optimize process systems. Two newer areas relevant to computer science that are impacting process systems engineering are cybersecurity and quantum computing. This work reviews some of our group’s recent work in control-theoretic approaches to control system cybersecurity and touches upon the use of quantum computers, with perspectives on the relationships between process design and control when cybersecurity and quantum technologies are of …


Wavelet-Based Harmonic Magnitude Measurement In The Presence Of Interharmonics, Flavio Costa, Stefan Häselbarth, Sergey Yanchenko, Kai Strunz, Aurenice M. Oliveira Jan 2023

Wavelet-Based Harmonic Magnitude Measurement In The Presence Of Interharmonics, Flavio Costa, Stefan Häselbarth, Sergey Yanchenko, Kai Strunz, Aurenice M. Oliveira

Michigan Tech Publications, Part 1

The increasing proliferation of power electronic converters, nonlinear loads, and distributed generation are leading to increased levels of harmonic and interharmonics in power networks. As a consequence, power quality (PQ) has become a critical performance indicator for power utilities and end-users. This study proposes a novel harmonic estimation method based on the real-time stationary discrete wavelet packet transform (RT-SDWPT). The proposed technique decomposes an input signal into frequency bands with harmonic information at cutoff frequencies and uses a compensation strategy to estimate root mean square (RMS) values of harmonics at every sampling period. The performance and effectiveness of the proposed …


Deep Learning Framework For Intelligent Pavement Condition Rating: A Direct Classification Approach For Regional And Local Roads, Waqar Shahid Qureshi, David Power, Ihsan Ullah, Brian Mulry, Kieran Feighan, Susan Mckeever, Dympna O'Sullivan Jan 2023

Deep Learning Framework For Intelligent Pavement Condition Rating: A Direct Classification Approach For Regional And Local Roads, Waqar Shahid Qureshi, David Power, Ihsan Ullah, Brian Mulry, Kieran Feighan, Susan Mckeever, Dympna O'Sullivan

Articles

Transport authorities rely on pavement characteristics to determine a pavement condition rating index. However, manually computing ratings can be a tedious, subjective, time-consuming, and training-intensive process. This paper presents a deep-learning framework for automatically rating the condition of rural road pavements using digital images captured from a dashboard-mounted camera. The framework includes pavement segmentation, data cleaning, image cropping and resizing, and pavement condition rating classification. A dataset of images, captured from diverse roads in Ireland and rated by two expert raters using the pavement surface condition index (PSCI) scale, was created. Deep-learning models were developed to perform pavement segmentation and …


Enhanced Fractional Adaptive Processing Paradigm For Power Signal Estimation, Naveed Ishtiaq Chaudhary, Zeshan Aslam Khan, Muhammad Asif Zahoor Raja, Iqra Ishtiaq Chaudhary Jan 2023

Enhanced Fractional Adaptive Processing Paradigm For Power Signal Estimation, Naveed Ishtiaq Chaudhary, Zeshan Aslam Khan, Muhammad Asif Zahoor Raja, Iqra Ishtiaq Chaudhary

Articles

Fractional calculus tools have been exploited to effectively model variety of engineering, physics and applied sciences problems. The concept of fractional derivative has been incorporated in the optimization process of least mean square (LMS) iterative adaptive method. This study exploits the recently introduced enhanced fractional derivative based LMS (EFDLMS) for parameter estimation of power signal formed by the combination of different sinusoids. The EFDLMS addresses the issue of fractional extreme points and provides faster convergence speed. The performance of EFDLMS is evaluated in detail by taking different levels of noise in the composite sinusoidal signal as well as considering various …


Rapid Detection Of Sars-Cov-2 Nucleocapsid Protein By A Label-Free Biosensor Based On Optical Fiber Cylindrical Micro-Resonator, Ru-Lei Xia, Bin Liu, Yingying Hu, Juan Liu, Yue Fu, Xing-Dao He, Ping Lu, Yingying Hu, Gerald Farrell Jan 2023

Rapid Detection Of Sars-Cov-2 Nucleocapsid Protein By A Label-Free Biosensor Based On Optical Fiber Cylindrical Micro-Resonator, Ru-Lei Xia, Bin Liu, Yingying Hu, Juan Liu, Yue Fu, Xing-Dao He, Ping Lu, Yingying Hu, Gerald Farrell

Articles

The current global outbreak of coronavirus (COVID-19) continues to be a severe threat to human health. Rapid, low-cost, and accurate antigen detection methods are very important for disease diagnosis. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) nucleocapsid protein (N-Protein) is often used as the diagnostic and screening for coronavirus detection. To this end, we propose and experimentally validate a highly sensitive whispering gallery mode (WGM) optical cylindrical micro-resonator (CMR) for bio immunoassay detection. To study the biokinetic process of immunoassay, the surface of the WGM micro-resonator is functionalized with N-Protein monoclonal antibody (N-Protein-m Ab), which led to the specific detection …


A Path Planning Framework For Multi-Agent Robotic Systems Based On Multivariate Skew-Normal Distributions, Peter Estephan Jan 2023

A Path Planning Framework For Multi-Agent Robotic Systems Based On Multivariate Skew-Normal Distributions, Peter Estephan

Theses, Dissertations and Capstones

This thesis presents a path planning framework for a very-large-scale robotic (VLSR) system in an known obstacle environment, where the time-varying distributions of agents are applied to represent the multi-agent robotic system (MARS). A novel family of the multivariate skew-normal (MVSN) distributions is proposed based on the Bernoulli random field (BRF) referred to as the Bernoulli-random-field based skew-normal (BRF-SN) distribution. The proposed distributions are applied to model the agents’ distributions in an obstacle-deployed environment, where the obstacle effect is represented by a skew function and separated from the no-obstacle agents’ distributions. First, the obstacle layout is represented by a Hilbert …


Deactivation Effects Of Tb3+ On Ho3+ Emission In Fluoroindate Glasses For 3.9 Μm Laser Applications, Zhi Zhang, Zhuowei Cheng, Ruicong Wang, Shunbin Wang, Gerald Farrell, Shijie Jia, Pengfei Wang Jan 2023

Deactivation Effects Of Tb3+ On Ho3+ Emission In Fluoroindate Glasses For 3.9 Μm Laser Applications, Zhi Zhang, Zhuowei Cheng, Ruicong Wang, Shunbin Wang, Gerald Farrell, Shijie Jia, Pengfei Wang

Articles

A series of Ho3+/Tb3+ co-doped fluoroindate glasses with good thermal stability have been synthesized to study the deactivation effects of Tb3+ on the Ho3+: 3.9 μm emission. Efficient 3.9 μm emission enhancement is obtained under excitation by an 888 nm laser diode (LD). The Judd-Ofelt (J-O) intensity parameters and radiative properties are calculated to evaluate the spectroscopic properties. Possible energy transfer processes resulting in emission reinforcement are discussed. A higher spontaneous transition probability and larger peak emission cross section are achieved with the inclusion of Tb3+. This analysis supports the conclusion that Ho3+/Tb3+ co-doped fluoroindate glass is a potentially useful …


High-Sensitivity Vector Bend Sensor Based On A Fiber Directional Coupler Inscribed By A Femtosecond Laser, Ke Tian, Mingyuan Zhang, Chuanzhein Zhao, Huibin Li, Shilong Li, Yuxuan Jiang, Gerald Farrell, Pengfei Wang Jan 2023

High-Sensitivity Vector Bend Sensor Based On A Fiber Directional Coupler Inscribed By A Femtosecond Laser, Ke Tian, Mingyuan Zhang, Chuanzhein Zhao, Huibin Li, Shilong Li, Yuxuan Jiang, Gerald Farrell, Pengfei Wang

Articles

In this Letter, we demonstrate a high-sensitivity vector bend sensor based on a fiber directional coupler. The fiber directional coupler is composed of two parallel waveguides inscribed within a no-core fiber (NCF) by a femtosecond laser. Since the two written waveguides have closely matched refractive indices and geometries, the transmission spectrum of the fiber directional coupler possesses periodic resonant dips. Such a fiber directional coupler exhibits a good bending-dependent spectral shift response due to its asymmetric structure. Experimental results show that bending sensitivities of -97.11 nm/m-1 and 58.22 nm/m-1 are achieved for the 0° and 180° orientations in the curvature …


Efficient 2075-Nm Laser Emission From Ho3+-Doped Fluorotellurite Glass In A Compact All-Fiber Structure, Liyuan Wang, Xiaotong Zhao, Nian Lv, Niannian Xu, Zhenrui Li, Gerald Farrell, Shunbin Wang, Pengfei Wang Jan 2023

Efficient 2075-Nm Laser Emission From Ho3+-Doped Fluorotellurite Glass In A Compact All-Fiber Structure, Liyuan Wang, Xiaotong Zhao, Nian Lv, Niannian Xu, Zhenrui Li, Gerald Farrell, Shunbin Wang, Pengfei Wang

Articles

In this Letter, we report an Ho3+-doped fluorotellurite glass all-fiber laser at 2075 nm. The gain fiber is pumped in-band with a 1976-nm fiber laser and connected by fusion splicing. A high-quality fusion splicing point with a loss of < 0.1 dB was obtained by finely adjusting the splicing power and offset. In addition, by optimizing the writing parameters, a third-order fiber Bragg grating (FBG) with a reflectivity of 98% was achieved at 2075 nm using the femtosecond laser direct-writing method. Using the FBG as the laser cavity mirror and a relatively short 28-cm-long home-made Ho3+-doped fluorotellurite fiber as the laser medium, a laser with a maximum unsaturated output power of 7.33 W was obtained, and the corresponding slope efficiency was as high as 93.4%. The first, to the best of our knowledge, demonstration of the fluorotellurite glass all-fiber ∼2.1-µm laser presented in this work may pave the way for a high-power 2.1-µm fiber laser with a compact structure.


Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd Jan 2023

Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd

Directivity

No abstract provided.


Zno Varistors – The Ideal Microstructure And Characteristics, And Methods Investigated And Developed To Achieve These, Maura Kelleher Jan 2023

Zno Varistors – The Ideal Microstructure And Characteristics, And Methods Investigated And Developed To Achieve These, Maura Kelleher

Books/Book Chapters

ZnO-Bi2O3-Sb2O3 varistors have been extensively studied since their discovery 5 decades ago. Their function in protecting increasingly sensitive electronic components by absorbing random surges of energy is even more important today. Also, the metal oxides from which they are made from are becoming even more precious. Their electrical characteristics are highly dependent on their microstructural characteristics which are highly dependent on their composition and methods used. The purpose of this article is to explain the ideal microstructure required to obtain the ideal electrical characteristics, the powder preparation methods investigated and developed to achieve it, and some future directions are outlined.