Engineering Commons^™

Observation And Understanding Of The Initial Unstable Electrical Contact Behaviors, Wanbin Ren, Nan Jiang, Cheng Chang, Shengjun Xue, Yu Chen, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Reliable and long-lifetime electrical contact is a very important issue in the field of radio frequency microelectromechanical systems (MEMS) and in energy transmission applications. In this paper, the initial unstable electrical contact phenomena under the conditions of micro-newton-scale contact force and nanometer-scale contact gap have been experimentally observed. The repetitive contact bounces at nanoscale are confirmed by the measured instantaneous waveforms of contact force and contact voltage. Moreover, the corresponding physical model for describing the competition between the electrostatic force and the restoring force of the mobile contact is present. Then, the dynamic process of contact closure is explicitly calculated …

On-Chip Detection Of Gel Transition Temperature Using A Novel Micro-Thermomechanical Method, Tsenguun Byambadorj, Erfan Dashtimoghadam, Mohamadali Malakoutian, Benyamin Davaji, Lobat Tayebi, James E. Richie, Chung-Hoon Lee

Electrical and Computer Engineering Faculty Research and Publications

We present a new thermomechanical method and a platform to measure the phase transition temperature at microscale. A thin film metal sensor on a membrane simultaneously measures both temperature and mechanical strain of the sample during heating and cooling cycles. This thermomechanical principle of operation is described in detail. Physical hydrogel samples are prepared as a disc-shaped gels (200 μm thick and 1 mm diameter) and placed between an on-chip heater and sensor devices. The sol-gel transition temperature of gelatin solution at various concentrations, used as a model physical hydrogel, shows less than 3% deviation from in-depth rheological results. …

Broadband Polarization Conversion With Anisotropic Plasmonic Metasurfaces, W. Cao, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Klein Tunneling Near The Dirac Points In Metal-Dielectric Multilayer Metamaterials, L. Sun, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Secure Transmission With Large Numbers Of Antennas And Finite Alphabet Inputs, Yongpeng Wu, Jun Bo Wang, Jue Wang, Robert Schober, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we investigate secure transmission over the large-scale multiple-antenna wiretap channel with finite alphabet inputs. First, we investigate the case where instantaneous channel state information (CSI) of the eavesdropper is known at the transmitter. We show analytically that a generalized singular value decomposition (GSVD)-based design, which is optimal for Gaussian inputs, may exhibit a severe performance loss for finite alphabet inputs in the high signal-to-noise ratio regime. In light of this, we propose a novel Per-Group-GSVD (PG-GSVD) design, which can effectively compensate the performance loss caused by the GSVD design. More importantly, the computational complexity of the PG-GSVD …

Recovery Of Phosphate Minerals From Plant Tailings Using Direct Froth Flotation, Ashraf Alsafasfeh, Lana Z. Alagha

Mining Engineering Faculty Research & Creative Works

Wastes produced from the phosphate industry presents many challenges due to the high economic and environmental impacts involved with their disposal. However, the relative scarcity of high-grade phosphate ores has driven researchers to recover and recycle these valuable wastes (secondary sources). The goal of this study was to investigate the possibility of upgrading the P₂O₅ content in tailings produced from a phosphorous production plant using direct froth flotation. Characterization assays, including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), and mineral liberation analysis (MLA), were first conducted to identify the mineralogical and morphological characteristics of …

Identifying Corrosion Zones In Coastal Regions For Metal Pipes -- A Gis Approach, Sanjay Tewari, Francis Manning

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Transportation agencies often allow metal pipes as an option for cross drains under/along roads and highways. Metal culverts can corrode over time at various rates based on their environmental conditions (e.g., corrosive nature of coastal soils, high water table and saltwater intrusion). This paper focuses on applying readily available soil data such as spatial distribution of soil types and soil characteristics (e.g., pH and conductivity) towards creating a geospatial information system (GIS) based approach to identifying corrosion zones in the coastal regions. A combination of data, obtained from field surveys provided by the Louisiana Transportation Research Center and Web Soil …

Unified Solution To Drained Expansion Of A Spherical Cavity In Clay And Sand, Lin Li, Jingpei Li, De'an Sun, Weibing Gong

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This paper presents a novel unified solution to drained expansion of a spherical cavity in both clay and sand. The large-strain theory and a critical state model with a unified hardening parameter are used to describe the elastoplastic behavior of the soils after yielding. The elastoplastic constitutive tensor of the critical state model is developed to be a system of first-order differential equations for the drained expansion of a spherical cavity. The problem is formulated as an initial value problem in terms of the Lagrangian scheme by introducing an auxiliary variable and is solved numerically. With the present solution, curves …

Magnetic Control Of Lateral Migration Of Ellipsoidal Microparticles In Microscale Flows, R. Zhou, C. A. Sobecki, J. Zhang, Yanzhi Zhang, Cheng Wang

Mathematics and Statistics Faculty Research & Creative Works

No abstract provided.

On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan

Faculty Publications

We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering-gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the …

How To Enhance Interdisciplinary Competence—Interdisciplinary Problem-Based Learning Versus Interdisciplinary Project-Based Learning, Mirjam Brassler, Jan Dettmers

Interdisciplinary Journal of Problem-Based Learning

Interdisciplinary competence is important in academia for both employability and sustainable development. However, to date, there are no specific interdisciplinary education models and, naturally, no empirical studies to assess them. Since problem-based learning (PBL) and project-based learning (PjBL) are learning approaches that emphasize students’ collaboration, both pedagogies seem suitable to enhance students’ interdisciplinary competence. Based on the principle of constructive alignment and four instructional principles on interdisciplinary learning, this paper proposes that students profit more from interdisciplinary PBL (iPBL) than interdisciplinary PjBL (iPjBL). A pre-post study was conducted with a sample of 95 students participating in iPBL and 183 students …

A Geologic Study To Determine The Potential To Create An Appalachian Storage Hub For Natural Gas Liquids, Kristin M. Carter, Douglas G. Patchen, Jessica P. Moore, Mohammad Fakhari, Gary W. Daft Jr, Michael Solis, Brian J. Dunst, Robin V. Anthony, Katherine W. Schmid, Kyle Metz, Philip Dinterman, Julie M. Bloxson, Erica N. Schubert, John Saucer

Appalachian Oil and Natural Gas Research Consortium

The Marcellus and Utica shale plays continue to lead the way in an ever-expanding shale revolution with average daily production, growing from about 3 billion cubic feet (BCF) in 2010 to more than 24 BCF today. Forecasts suggest that this could grow to as much as 40 BCF in the next 5 years. Fortunately, sweet spots in the Utica in eastern Ohio and in the Marcellus in northern West Virginia and southwestern Pennsylvania are areas of wet gas production, downdip from oil production and updip from dry gas. Production in these regions represents about 40 percent of the total from …

Conference Program, Ulf Olsson, Norman Wagner, Anand Yethiraj

Association in Solution IV

No abstract provided.

Multisequence Algorithm For Coarse-Grained Biomolecular Simulations: Exploring The Sequence-Structure Relationship Of Proteins, Adekunle Aina, Stefan Wallin

Association in Solution IV

Many biologically motivated problems naturally call for the investigation and comparison of molecular variants, such as determining the mechanisms of specificity in biomolecular interactions or the mechanisms of molecular evolution. We consider a generalized ensemble algorithm for coarse-grained simulations of biomolecules which allows the thermodynamic behavior of two or more sequences to be determined in a single multisequence run. By carrying out a random walk in sequence space, the method also enhances conformational sampling. Escape from local energy minima is accelerated by visiting sequences for which the minima are shallower or absent. We test the method on an intermediate-resolution coarse-grained …

Three-Dimensional Printing Of "Green" Fuels For Low-Cost Small Spacecraft Propulsion Systems, Stephen A. Whitmore

Mechanical and Aerospace Engineering Faculty Publications

This paper details the advantages of employing modern additive manufacturing methods to fabricate hybrid rocket fuels for intrinsically safe and green small spacecraft propulsion systems. Using additive manufacturing overcomes multiple issues frequently associated with hybrid propulsion, including poor volumetric efficiency, system ignitability, and low fuel regression rates. When certain three-dimensionally printed thermoplastics are subjected to a high-voltage low-wattage charge, electrostatic arcing along the surface pyrolizes a small amount of material that, with the introduction of an oxidizer, “seeds” combustion and produces immediate and reliable ignition. Thermoplastic fuel grains can be printed with port shapes that enhance burn properties and increase …

Molecular Dynamics Modeling And Simulation Of Bitumen Chemical Aging, Farshad Fallah

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Chemical aging of asphalt binder leads to significant changes in its mechanical and rheological properties, resulting in poor pavement behavior and distress. Various laboratory methods have been used to simulate asphalt aging during the service life of the pavement. However, controversy exists regarding the capability of these methods to predict field aging, as various factors interact with the pavement during service and the mechanism behind aging is not fully understood. The two main outcomes of chemical aging are oxidation of asphalt molecules, and change in asphalt SARA (saturate, aromatic, resin, and asphaltene) fractions. Reaction of oxygen with asphalt components forms …

Decoupling Information And Connectivity In Information-Centric Networking, Hila Ben Abraham, Jyoti Parwatikar, John Dehart, Adam Drescher, Patrick Crowley

All Computer Science and Engineering Research

This paper introduces and demonstrates the concept of Information-Centric Transport as a mechanism for cleanly decoupling the information plane from the connectivity plane in Information-Centric Networking (ICN) architectures, such as NDN and CICN. These are coupled in today's incarnations of NDN and CICN through the use of forwarding strategy, which is the architectural component for deciding how to forward packets in the presence of either multiple next-hop options or dynamic feedback. As presently designed, forwarding strategy is not sustainable: application developers can only confidently specify strategy if they understand connectivity details, while network node operators can only confidently assign strategies …

Prediction Of Graduation Delay Based On Student Characterisitics And Performance, Tushar Ojha

Electrical and Computer Engineering ETDs

A college student's success depends on many factors including pre-university characteristics and university student support services. Student graduation rates are often used as an objective metric to measure institutional effectiveness. This work studies the impact of such factors on graduation rates, with a particular focus on delay in graduation. In this work, we used feature selection methods to identify a subset of the pre-institutional features with the highest discriminative power. In particular, Forward Selection with Linear Regression, Backward Elimination with Linear Regression, and Lasso Regression were applied. The feature sets were selected in a multivariate fashion. High school GPA, ACT …

Ros Based High Performance Control Architecture For An Aerial Robotic Testbed, Christoph Hintz

Electrical and Computer Engineering ETDs

The purpose of this thesis is to show the development of an aerial testbed based on the Robot Operating System (ROS). Such a testbed provides flexibility to control heterogenous vehicles, since the robots are able to simply communication with each other on the High Level (HL) control side. ROS runs on an embedded computer on-board each quadrotor. This eliminates the need of a Ground Base Station, since the complete HL control runs on-board the Unmanned Aerial Vehicle (UAV).

The architecture of the system is explained throughout the thesis with detailed explanations of the specific hardware and software used for the …

Empirical Study On The Accessibility Of Wi-Fi, Computers And Cell Phones In Cuba, Katalina Montalvo

Student Works

This paper reviews the accessibility of technology in Havana, Cuba as it begins to open its borders to the modern world. The technology researched includes cell phones, Wi-Fi, computers, and personal computers. As the embargo on Cuba begins to fade, tourists and new businesses are flocking to this once heavily restricted island. The focus of this paper is to explain the availability of modern technology to the citizens of Cuba. Currently, technology is very limited in Cuba because Wi-Fi is an expensive luxury for the average Cuban. Modern computers are also an expensive purchase, which forces Cubans to put together …

Analysis Of Strength Of Glass Fibre Composite Leaf Spring Using Finite Element Method, Andoko Andoko, Poppy Puspitasari, Avita Ayu Permanasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Leaf spring, as one of the main components of the suspension system, serves the function of absorbing road shocks and any wheel vibrations, preventing them from being transmitted directly to the vehicle body. Moreover, it can increase the tire traction as well as support the weight of the vehicle and various kinds of external forces. Various studies on the use of composite materials for leaf springs have shown that the strength of composite leaf spring is similar to steel leaf spring with the same load carrying capacity. However, the composite leaf spring has the added advantage of being more lightweight. …

Analysis Of Biodegradation Of Bioplastics Made Of Cassava Starch, Nanang Eko Wahyuningtiyas, Heru Suryanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Environmental pollution due to plastic waste taking too long to decompose has become a global problem. There have been numerous solutions proposed, one of which is the use of bioplastics. The use of cassava starch as the main ingredient in the manufacture of bioplastics shows great potential, since Indonesia has a diverse range of starch-producing plants. The aim of the present study is to analyse the effect of glycerol on microbial degradation. This experimental research investigated the use of cassava flour mixed with glycerol plasticizer at various concentrations (0, 2, 2.5, 3%) in the synthesis of bioplastics. The aspects studied …

Effect Of Magnetic Field On Diesel Engine Power Fuelled With Jatropha-Diesel Oil, Sukarni Sukarni, Partono Partono, Deni Krisdianto, Retno Wulandari

Journal of Mechanical Engineering Science and Technology (JMEST)

Jatropha oil has characteristics very close to the diesel fuel, so it has good prospects as a substitute or as a mixture of diesel fuel. Previous research showed that jatropha oil usage in diesel engines caused power to decrease. It was probably owing to the higher viscosity of the Jatropha oil compared to that of diesel oil. Installing the magnetic field in the fuel line of a diesel engine fueled with jatropha-diesel oil is expected to reduce the viscosity of jatropha-diesel oil mixture, hence improve the combustion reaction process. This research aims to know the influence of the magnetic field …

Utilization Of Carbon Nanotubes In Electromagnetic Wave Detectors, Muhammad Hanis Zakariah, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Direct detection of hydrocarbon by an active source using electromagnetic (EM) energy termed seabed logging (SBL) has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges include sensitivity and frequency matching. This paper presents development of the carbon nanotubes (CNTs) as electromagnetic wave detector due to outstanding properties of carbon nanotubes. They are currently one of the desired materials for advanced technologies. Two types of detectors were developed in this work, carbon nanotube-based (D1) and without nanotubebased (D2) detectors. Various configuration and arrangement for each type of detector were investigated to determine the one …

Factors Affecting The Surface Roughness In Sinking Edm Process, Ahmad Atif Fikri, Maftuchin Romlie, Aminnudin Aminnudin

Journal of Mechanical Engineering Science and Technology (JMEST)

The purpose of this study is to gain insights into the surface quality (smoothness) of sinking EDM machining products. Among other non-conventional machining processes, Electrical Discharge Machining (EDM) is the most commonly used process. EDM is a machining process that uses electric sparks created between a workpiece and a tool (electrode). As a manufacturing process, EDM is used for workpieces which have intricate contours and precise dimensions, and works by using electric discharges (sparks) applied in a rapid series of repetitive electrical discharges between the two electrodes, separated by a dielectric fluid, and subject to an electric voltage. Since the …

The Strength Of Moulding Sand Consisting Of A Mixture Of Bentonite, Tapioca Flour, And Sago Flour As A New Binder Formula To Improve The Quality Of Al-Si Cast Alloy, Andoko Andoko, Riana Nurmalasari, M. Alfian Mizar, Retno Wulandari, Poppy Puspitasari, Avita Ayu Permanasari

Journal of Mechanical Engineering Science and Technology (JMEST)

The major factors determining the quality of sand casting products are the base sand and the composition of the sand mould and the binding material. In the foundry industry, the most commonly used binder for creating sand moulds is bentonite. However, the price of bentonite is likely to keep rising. This study aimed at discovering a new binder formula associated with the effect of binder composition i.e. bentonite, tapioca flour, and sago flour on the basis of its mechanical and physical properties. The new formula was expected to be a better binder in the production of sand moulds, resulting in …

Optimum Conditions For Eor Using Nanofluids Subjected To Em Waves, Muhammad Kashif, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Today’s major challenge for oil industry is to improve the oil recovery from the reservoir. Various enhanced oil recovery (EOR) methods have been applied in the field and the steam injection is one of the most favourable methods. The deep reservoir will result in failure of this method due to excessive heat dissipation. In this situation, generating and injecting steam may be uneconomical due to the tremendous reduction of the recovery. Some methods using nanotechnology have been introduced and elaborated. However, we propose the electromagnetic (EM) method as an alternative due to its long range transmission of the transverse waves. …

Cement Improved Highly Weathered Phyllite For Highway Subgrades: A Case Study In Shaanxi Province., Xuesong Mao, Carol Jean Miller, Longqi Liu

Civil and Environmental Engineering Faculty Research Publications

In a cost-saving move, the soft rocks composed of highly-weathered phyllites available onsite were used to fill the subgrade in the eastern Ankang section of the expressway of Shiyan to Tianshui, China. Cement admixture was used to improve the performance of the weathered phyllites. In order to determine the best mix ratio, values corresponding to compaction performance, unconfined compressive strength, and the California bearing ratio (CBR) were analyzed for variable cement content weight percentages (3%, 4%, 5%, and 6%) using test subgrade plots in the field. Field measurements of resilience modulus and deflection confirmed that the strength of the subgrade …

Visualization Of The Cardiac Excitation And Pvc Arrhythmia On A 3d Heart Model, Pranav Sreedharan Veliyara

Masters Theses

Visualization of the cardiac potential movement is important in understanding the physiology of the human heart. A 3D visualization tool will help the cardiology students and others interested in human physiology to understand the functioning of the heart. In this thesis, such a tool is proposed which helps in the visualization of the cardiac potential movement and Premature Ventricular Contraction (PVC) event on a 3D heart model. The cardiac excitation obtained from a limb lead and a precordial lead of a 12 lead electrocardiograph (ECG) is mapped on a 3D heart model with fixed conduction pathways. The 3D heart model …

Glucose Recovery From Different Corn Stover Fractions Using Dilute Acid And Alkaline Pretreatment Techniques, D. Aboagye, N. Banadda, R. Kambugu, Jeffrey Seay, N. Kiggundu, A. Zziwa, I. Kabenge

Chemical and Materials Engineering Faculty Publications

Background: Limited availability of corn stover due to the competing uses (organic manure, animal feed, bio-materials, and bioenergy) presents a major concern for its future in the bio-economy. Furthermore, biomass research has exhibited different results due to the differences in the supply of enzymes and dissimilar analytical methods. The effect of the two leading pretreatment techniques (dilute acid and alkaline) on glucose yield from three corn stover fractions (cob, stalk, and leaf) sourced from a single harvest in Uganda were studied at temperatures 100, 120, 140, and 160 °C over reaction times of 5, 10, 30, and 60 min.

Results: …