Engineering Commons^™

Cvd Preparation And Application Of 3d Graphene In Electrochemical Energy Storage, Yong-Kang Xia, Ming-Yuan Gu, Hong-Guan Yang, Xin-Zhi Yu, Bing-An Lu

Journal of Electrochemistry

Three-dimensional (3D) graphene combinations with the excellent intrinsic properties of graphene and the 3D micro/nano porous structures provide a graphene foam with high specific surface area, excellent mechanical strength and fast electron and mass transports. The 3D graphene foam and its composite nanomaterials are widely used in the fields of nano-electronics, energy storage, chemical and biological sensing. The 3D graphene foam prepared by chemical vapor deposition (CVD) method is of high purity and crystallinity.  In this review, a brief overview in the CVD preparations of 3D graphene and properties of CVD prepared 3D graphene based nanomaterials in electrochemical energy storage …

Applications Of Advanced Imaging Technologies For Critical Issues Of All-Solid-State Lithium Battery Studies, Yi-Bo Zhao, Hui-Hui Liu, Song-Liang Chen, Shou-Hang Bo

Journal of Electrochemistry

All-solid-state lithium batteries have attracted much attention for their high energy density and good safety. To increase their efficiency and prolong their service life, it is necessary to achieve high ion conductivity at the electrode/electrolyte interface and in the electrolyte, as well as to eliminate dendrites growth in the battery. Based on the critical requirements outlined above, this paper discusses the applications of advanced imaging technologies in relevant studies. Recent progresses in investigations of all-solid-state lithium batteries by imaging techniques including electron microscopy, scanning probe microscopy, X-ray tomography, magnetic resonance imaging and optical microscopy are summarized.

Synthesis Of Flower-Like Vanadium Disulfide For Lithium Storage Application, Pan Li, Jian Liu, Wei-Yi Sun, Hai-Xia Li, Zhan-Liang Tao

Journal of Electrochemistry

In order to improve the electrochemical properties of vanadium disulfide (VS₂) as an electrode material in Li-ion battery, the flower-like VS₂ was prepared by a one-step hydrothermal method with the addition of polyethylene glycol 400. The phase and morphology of the product were characterized by using X-ray diffraction and field emission scanning electron microscopy. During the growth process, it was observed that the flower-like VS₂ was interspersed with several hexagonal vanadium disulfide nanosheets, which had a high specific surface area and excellent structural stability. The flower-like VS₂ was used for the cathode material test in …

Ni/Mn3O4/Nimn2O4 Double-Shelled Hollow Spheres Embedded Into Reduced Graphene Oxide As Advanced Anodes For Sodium-Ion Batteries, Chong Yan, Hua-Ri Kou, Bo Yan, Xiao-Jing Liu, De-Jun Li, Xi-Fei Li

Journal of Electrochemistry

Delicately building the unique nanocomposite with the combination of hollow structure and reduced graphene oxide (rGO) is highly desirable and still remains a great challenge in the field of energy conversion and storage. In this work, Ni/Mn₃O₄/NiMn₂O₄ double-shelled hollow spheres coated by rGO (denoted as R-NMN) have been successfully synthetized via one-step rapid solvothermal treatment followed by subsequent annealing for the first time. Served as anodes for sodium ion batteries (SIBs), the R-NMN composite containing 25wt% rGO exhibits a high discharge capacity of 187.8 mAh·g^-1 after 100 cycles at 50 mA·g^{-1 …}

Preface On Special Issue Of Next-Generation Secondary Batteries, Zhen Zhou, Quan-Feng Dong

Journal of Electrochemistry

No abstract provided.

A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak

Faculty Publications

The realization of Internet of Underground Things (IOUT) relies on the establishment of reliable communication links, where the antenna becomes a major design component due to the significant impacts of soil. In this paper, a theoretical model is developed to capture the impacts of change of soil moisture on the return loss, resonant frequency, and bandwidth of a buried dipole antenna. Experiments are conducted in silty clay loam, sandy, and silt loam soil, to characterize the effects of soil, in an indoor testbed and field testbeds. It is shown that at subsurface burial depths (0.1-0.4m), change in soil moisture impacts …

Effect Of Stoniness On The Hydraulic Properties Of A Soil From An Evaporation Experiment Using The Wind And Inverse Estimation Methods, Nerea Arias, Iñigo Virto, Alberto Enrique, Paloma Bescansa, Riley Walton, Ole O. Wendroth

Plant and Soil Sciences Faculty Publications

Stony soils are distributed all over the world. The study of their characteristics has gained importance lately due to their increasing use as agricultural soils. The effect that rock fragments exert on the soil hydraulic properties is difficult to measure in situ, and is usually derived from the fine earth properties. However, the corrections used so far do not seem accurate for all types of stony soils. Our objective was to assess the adequacy of estimating the hydraulic properties of a stony soil from the fine earth ones by correcting the latter by the volume occupied by rock fragments. To …

Health Benefits From Upgrading Public Buses For Cleaner Air: A Case Study Of Clark County, Nevada And The United States, John O. Olawepo, L.-W. Antony Chen

School of Public Health Faculty Research

Public transit buses, which move more than 5 billion passengers annually in the United States (U.S.), can contribute substantially to the environmental health burden through emitted air pollutants. As a leader in transforming to cleaner bus fleets, the Regional Transport Commission of Southern Nevada (RTC) has been transitioning from diesel to compressed natural gas (CNG) transit buses since 1999. By 2017, ~75% of RTC’s buses operating in Clark County, Nevada were CNG-powered. This study assesses the health benefits of the venture using the US Environmental Protection Agency’s (EPA) Co-Benefits Risk Assessment (COBRA) model, considering the emission and exposure changes from …

Venezuela Undermines Gold Miner Crystallex's Attempts To Recover On Its Icsid Award, Sam Wesson

Loyola of Los Angeles International and Comparative Law Review

No abstract provided.

Great Modules In Drupal 7... And Drupal 8...?, Rachel S. Evans, Lauren Blais

Presentations

The two presenters each shared their favorite Drupal modules, giving site examples of each in action and talking about the benefits and drawbacks of each. Most UGA websites using Drupal are in the process of migrating content from 7 to 8, so each module discussed was then described in terms of availability in 8. The following five modules were explored:

• Quick Tabs
• Flex Slider
• Geolocation and Leaflet
• Biblio (not in D8)
• Environment Indicator

Recent Progress In Vanadium-Based Electrode Materials, Meng-Lei Sun, Da-Qi Zhang, Jin-Kui Feng, Jiang-Feng Ni

Journal of Electrochemistry

It is an important solution to solve energy storage problems by developing inexpensive and safe lithium-ion and sodium-ion batteries with superior performance. Vanadium-based electrode materials are promising electrode materials because of diversified chemical valences, open structures and high theoretical capacities. In the past few years, vanadium-based electrode materials such as oxides, sulfides, and phosphates have achieved a considerable development in the battery field, It is,  therefore, necessary to summarize their recent research progress. In this review, we particularly highlight the key challenges that are facing in the application of vanadium materials, such as low ion diffusion coefficient and poor structural …

Design And Implementation Of A 72 & 84 Ghz Terrestrial Propagation Experiment; Exploitation Of Nexrad Data To Statistically Estimate Rain Attenuation At 72 Ghz, Nicholas Pawel Tarasenko

Electrical and Computer Engineering ETDs

The wireless communication sector is rapidly approaching network capacities as a direct result of increasing mobile broadband data demands. In response, the Federal Communications Commission allocated 71-76 GHz “V-band” and 81-86 GHz “W-band” for terrestrial and satellite broadcasting services. Movement by the telecommunication industry towards W/V-band operations is encumbered by a lack of validated and verified propagation models, specifically models to predict attenuation due to rain. Additionally, there is insufficient data available at W/V-bands to develop or test propagation models. The first aim of this study was the successful installation and operation of a terrestrial link to collect propagation data …

Emerging Need For A European Approach To Space Traffic Management, Tomas Hrozensky

Space Traffic Management Conference

The intensification of space activities worldwide, together with the emergence of new actors and disruptive concepts (e.g. miniaturized satellites, mega-constellations, in-orbit operations), create new challenges to ensure the safety and security of space systems and operations as well as the long-term sustainability of space activities. Among policy responses to these challenges, the development of a new approach to space traffic management was recently brought to the forefront by the adoption of a policy directive in this domain by the United States.

A comparable STM policy has not yet been developed in Europe even though considerations for the safety, security and …

U.S. Navy Pilot Competence: An Exploratory Study Of Flight Simulation Training Versus Actual Aircraft Training, Aaron D. Judy, Tom Gollery

Journal of Applied Social Science Research and Practice

The purpose of this study was to investigate the relationships between US Navy T-45C flight simulation training time, actual aircraft training time, and intermediate and advanced jet pilot competence as measured by the Naval Standard Score (NSS). Examining the relationships between US Navy T-45C flight simulation time and actual aircraft flight time may provide further information on flight simulation training versus actual aircraft training to aviation authorities, flight instructors, the military aviation community, the commercial aviation community, and academia. The study was non-experimental, correlational, causal-comparative with an emphasis upon the establishment of mathematic and predictive relationships using archival data from …

Development Of Image Analysis Technique For Quantification Of Recrystalization, Bersabe Morales

Mechanical Engineering Master's Theses

Development of metallic components with desired properties for the new generation of applications requires precise design of grain structure. One of the most effective techniques for manipulating grain structure is by controlling the recrystallization process. Although recrystallization has been studied for many years, its proper and fast quantification is still a challenge. This work develops a new image analysis technique for quantification of recrystallization, as an alternative to intensive and expensive electron backscatter diffraction (EBSD) analysis. The image analysis program run on an optical micrograph, detect recrystallized regions and report: fraction recrystallized, average grain size and distribution. To examine the …

Aiming For Gold: Improving Reproducibility In Hydrology Studies | College Of Engineering, Utah State University

College of Engineering News

In six well-regarded hydrology and water resources journals published in 2017, the estimated percentage of studies whose results could be fully reproduced was only between 0.06 and 6.8 percent. This low level of reproducibility is not uncommon in hydrology studies — a fact many scientists readily acknowledge. However, a team of researchers at Utah State University may have found a solution to make these studies more reproducible.

Bio-Inspired Sensing And Actuating Architectures For Feedback Control Of Civil Structures, Courtney A. Peckens, I. Cook, C. Fogg

Faculty Publications

Civil structures, such as buildings and bridges, are constantly at risk of failure due to external environmental loads, such as earthquakes or strong winds. To minimize the effects of these loads, active feedback control systems have been proposed but such systems still face numerous challenges which impede their widespread adoption. In order to overcome many of these challenges, inspiration can be drawn from the signal processing and actuating techniques employed by the biological central nervous system to develop a bio-inspired control algorithm. In this study the front-end, signal processing techniques employed by biological sensory systems, and in particular the mammalian …

Authentication Of Medical Herbals By Multispectral Analysis, Ait Kaddour Abderrahmane, Zhasur Esirgapovich Safarov, Shakhnoza Abduvakhitovna Sultanova

Chemical Technology, Control and Management

The results of the study concerning the ability of multispectral analysis to authenticate dried medicinal herbs of Uzbekistan are considered. Before obtaining the multispectral image, various medicinal plants (colored oregano grass (herbaoriganitytthianthi) and shepherd's pouch (capsellabursa-pastoris) were subjected to different drying conditions to increase the variability of the plant database and reproduce the conditions. Drying experiments were carried out in the laboratory of Tashkent state technical University. After drying, the images were collected using nineteen light-emitting diodes (405 to 1050 nm) using the Videometer Lab2 device. The image cubes were processed to extract the average spectra of the image. The …

Webinar: Rethinking Streets For Bikes: An Evidence Based Guide Of Bike-Friendly Street Retrofits, Marc Schlossberg, Roger Lindgren

TREC Webinar Series

There is a growing demand for better infrastructure and fewer barriers to biking and other forms of space-efficient micromobility. Tackling daily trips by bike is easier on the environment, healthier for users and non-users alike, uses precious urbanized public and private land more efficiently, costs taxpayers less to build and maintain infrastructure, and when routes are safe and comfortable, moving by bike is also fun! Complete Streets policies are being adopted across the country, and there is an active conversation around the safety imperative of a Complete Streets approach. Yet, local officials often need both design guidance and the …

Carbon Capture And Synergistic Energy Storage: Performance And Uncertainty Quantification, Christopher Stephen Russell

Theses and Dissertations

Energy use around the world will rise in the coming decades. Renewable energy sources will help meet this demand, but renewable sources suffer from intermittency, uncontrollable power supply, geographic limitations, and other issues. Many of these issues can be mitigated by introducing energy storage technologies. These technologies facilitate load following and can effectively time-shift power. This analysis compares dedicated and synergistic energy storage technologies using energy efficiency as the primary metric.
Energy storage will help renewable sources come to the grid, but fossil fuels still dominate energy sources for decades to come in nearly all projections. Carbon capture technologies can …

Satellite Conjunction Assessment Risk Analysis For “Dilution Region” Events: Issues And Operational Approaches, Matthew D. Hejduk

Space Traffic Management Conference

An important activity within Space Traffic Management is the detection and prevention of possible on-orbit collisions between space objects. The principal parameter for assessing collision likelihood is the probability of collision, which is widely accepted among conjunction assessment practitioners; but it possesses a known deficiency in that it can produce a false sense of safety when the orbital position uncertainties for the conjuncting objects are high. The probability of collision is said to be “diluted” in such a situation and to understate the possible risk; certain approaches have been recommended by researchers to provide (largely conservative) risk estimates and remediation …

End To End Satellite Servicing And Space Debris Management, Aman Chandra, Himangshu Kalita, Roberto Furfaro, Jekan Thanga

Space Traffic Management Conference

There is growing demand for satellite swarms and constellations for global positioning, remote sensing and relay communication in higher LEO orbits. This will result in many obsolete, damaged and abandoned satellites that will remain on-orbit beyond 25 years. These abandoned satellites and space debris maybe economically valuable orbital real-estate and resources that can be reused, repaired or upgraded for future use. Space traffic management is critical to repair damaged satellites, divert satellites into warehouse orbits and effectively deorbit satellites and space debris that are beyond repair and salvage. Current methods for on-orbit capture, servicing and repair require a large service …

Analogies And Comparisons For Stm Data Bodies, Phillip M. Cunio, Brien Flewelling

Space Traffic Management Conference

Space Traffic Management (STM) has already demonstrated its potential to be extremely data-intensive. The large number of objects on orbit today, if observed constantly throughout their lifetimes, could produce a staggeringly large number of observations that might in turn generate large numbers of orbits. Orbit data with a lengthy time history can be used to produce estimates of maneuver frequency, susceptibility to natural forces such as drag, and (if combined with photometric data) assessments of behavioral patterns of life.

A future of mega-constellations and a growing number of nations and organizations with assets on orbit would make it likely that …

Advanced Inflatable De-Orbit Solutions For Derelict Satellites And Orbital Debris, Aman Chandra, Greg Wilburn, Jekan Thanga

Space Traffic Management Conference

The exponential rise in small-satellites and CubeSats in Low Earth Orbit (LEO) poses important challenges for future space traffic management. At altitudes of 600 km and lower, aerodynamic drag accelerates de-orbiting of satellites. However, placement of satellites at higher altitudes required for constellations pose important challenges. The satellites will require on-board propulsion to lower their orbits to 600 km and let aerodynamic drag take-over. In this work we analyze solutions for de-orbiting satellites at altitudes of up to 3000 km. We consider a modular robotic de-orbit device that has stowed volume of a regular CubeSat. The de-orbit device would be …

Astria Ontology: Open, Standards-Based, Data-Aggregated Representation Of Space Objects, Jennie Wolfgang, Kathleen Krysher, Michael Slovenski, Unmil P. Karadkar, Shiva Iyer, Moriba K. Jah

Space Traffic Management Conference

The necessity for standards-based ontologies for long-term sustainability of space operations and safety of increasing space flights has been well-established [6, 7]. Current ontologies, such as DARPA’s OrbitOutlook [5], are not publicly available, complicating efforts for their broad adoption. Most sensor data is siloed in proprietary databases [2] and provided only to authorized users, further complicating efforts to create a holistic view of resident space objects (RSOs) in order to enhance space situational awareness (SSA).

The ASTRIA project is developing an open data model with the goal of aggregating data about RSOs, parts, space weather, and governing policies in order …

Near Real Time Satellite Event Detection And Characterization With Remote Photoacoustic Signatures, Justin Spurbeck, Moriba K. Jah

Space Traffic Management Conference

Active satellites frequently maneuver to mitigate conjunctions and maintain nominal mission orbits. With an ever-growing Resident Space Object (RSO) population, the need to detect and predict any changes in active RSO trajectories has become increasingly important. There is typically a lag on the order of hours to days from time of maneuver to unmodeled dynamic event detection depending on the magnitude of the delta-v. For uncooperative objects, this detection lag poses a threat to other satellites. Implementing an active photoacoustic signature change detection methodology to detect and predict unmodeled dynamic events would reduce the overall conjunction risk and provide a …

Lasers For Communication And Coordination Control Of Spacecraft Swarms, Himangshu Kalita, Leonard Dean Vance, Vishnu Reddy, Jekan Thanga

Space Traffic Management Conference

Swarms of small spacecraft offer whole new capabilities in Earth observation, global positioning and communications compared to a large monolithic spacecraft. These small spacecraft can provide bigger apertures that increase gain in communication antennas, increase area coverage or effective resolution of distributed cameras and enable persistent observation of ground or space targets. However, there remain important challenges in operating large number of spacecrafts at once. Current methods would require a large number of ground operators monitor and actively control these spacecraft which poses challenges in terms of coordination and control which prevents the technology from scaled up in cost-effective manner. …

Space Objects Classification And Characterization Via Deep Learning And Light Curves: Applications To Space Traffic Management, Roberto Furfaro, Richard Linares, Vishnu Reddy

Space Traffic Management Conference

Recent advancements in deep learning (e.g. Convolutional Neural Networks (CNN), Recurrent Neural networks (RNN)) have demonstrated impressive results in many practical and theoretical fields (e.g. speech recognition, computer vision, robotics). Whereas deep learning methods are becoming ubiquitous, they have been barely explored in SSA applications, in particular with regard to object characterization for Space Traffic Management (STM).

In this paper, we report the results obtained in designing and training a set of CNNs and RNNs for Space Object (SO) classification and characterization using light-curve measurements. More specifically, we provide a comparison between deep networks trained on both physically-based models (i.e. …

Nanosat Tracking And Identification Techniques And Technologies, Mark A. Skinner

Space Traffic Management Conference

Nanosats (and CubeSats, ‘Smallsats’, etc.) are of order 10 cm in size, and are at or near the limits of what can be tracked and characterized, using existing space surveillance assets. Additionally, given the CubeSat form-factor, they are often launched in large numbers (scores), and can be virtually identical. Thus are they difficult to track and to identify.

We have identified a number of technologies that future nanosat missions could employ that would enhance the trackability and/or identification of their satellites when on-orbit. Some of these technologies require active illumination of the satellite with electromagnetic energy, either in the radio …

A Statistical Approach For Commercial Space Vehicle Integration Into The National Airspace System, Christopher Hays, Daniel Chu, Pedro Llanos

Space Traffic Management Conference

This paper explores commercial space vehicle (CSV) suborbital flight trajectories in the temporal and spatial domains for CSV integration into the National Airspace System. The research data was collected via the Suborbital Space Flight Simulator (SSFS) housed in the College of Aviation at Embry-Riddle Aeronautical University - Daytona Beach campus, and analyzed using an original MATLAB data analytics tool. This study primarily focuses on statistical trends observed in previously simulated flights supported by three Project PoSSUM (Polar Suborbital Science in the Upper Mesosphere) campaigns comprised of 34 flights and 19 control flights, and to identify relevant milestones in the CSV …