Engineering Commons^™

Tensile Properties And Microstructures Of Laser-Formed Ti-6al-4v, J. Alcisto, A. Enriquez, H. Garcia, S. Hinkson, T. Steelman, E. Silverman, P. Valdovino, H. Gigerenzer, J. Foyos, J. Ogren, J. Dorey, K. Karg, T. Mcdonald, Omar S. Es-Said

Mechanical Engineering Faculty Works

The room temperature tensile properties of Ti-6Al-4V alloy prepared under two different processing routes were evaluated and compared. One group of samples was prepared by conventional casting-forging-rolling into flat plates. The other group was prepared by using Triton's Laser Free-Form Fabrication (LF3)(TM) processes, i.e., a laser was used to melt pre-alloyed powders of the required metallic composition as they were dropped onto a moveable substrate programmed to move in such a manner as to form a solid alloy plate. Five populations of Ti-6Al-4V were evaluated: a standard wrought form, an as-deposited form, a machined as-deposited form, a heat-treated as-deposited form, …

High-Resolution, Non-Contact Angular Measurement System For Psa/Rsa, Ronald D. Sloat

Master's Theses

A non-contact angular measurement system for Pitch Static Attitude (PSA) and Roll Static Attitude (RSA) of hard disk drive sliders is designed and built. Real-time sampling at over 15 KHz is achieved with accuracy of +/- 0.05 degrees over a range of approximately 2-3 degrees. Measuring the PSA and RSA is critical for hard drive manufacturers to control and improve the quality and reliability of hard drives. Although the hard drive industry is able to measure the PSA and RSA at the subassembly level at this time, there is no system available that is able to measure PSA/RSA at the …

Bs News March/April

Building Services Engineering

No abstract provided.

2011 (Spring) Ensi Informer, Morehead State University. Engineering Sciences Department

ENSI Informer Magazine Archive

The ENSI Informer Magazine published in the spring of 2011.

High Power Current Sensorless Bidirectional 16-Phase Interleaved Dc-Dc Converter For Hybrid Vehicle Application, Liqin Ni, Dean J. Patterson, Jerry L. Hudgins

Department of Electrical and Computer Engineering: Faculty Publications

A new 16-phase interleaved bidirectional dc/dc converter is developed featuring smaller input/output filters, faster dynamic response and lower device stress than conventional designs, for hybrid vehicle applications. The converter is connected between the ultracapacitor (UC) pack and the battery pack in a multisource energy storage system of a hybrid vehicle. Typically, multiphase interleaved converters require a current control loop in each phase to avoid imbalanced current between phases. This increases system cost and control complexity. In this paper, in order to minimize imbalance currents and remove the current control loop in each phase, the converter is designed to operate in …

Iterative Construction Of Regular Ldpc Codes From Independent Tree-Based Minimum Distance Bounds, Eric T. Psota, Lance C. Perez

Department of Electrical and Computer Engineering: Faculty Publications

An independent tree-based method for lower bounding the minimum distance of low-density parity-check (LDPC) codes is presented. This lower-bound is then used as the decision criterion during the iterative construction of regular LDPC codes. The new construction algorithm results in LDPC codes with greater girth and improved minimum-distance bounds when compared to regular LDPC codes constructed using the progressive edge-growth (PEG) construction and the approximate cycle extrinsic message degree (ACE)-constrained PEG construction. Simulation results of codes constructed with the new method show improved performance on the additive white Gaussian noise channel at moderate signal-to-noise ratios.

Runoff, Erosion, And Size Distribution Of Sediment From Beef Cattle Feedlots, John E. Gilley, Jason R. Vogel, Roger Eigenberg, David B. Marx, Brian L. Woodbury

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The size distribution of sediment in runoff from feedlot surfaces influences erosion rates and settling velocity. The objectives of this study were to: (1) measure runoff, erosion, and size distribution of sediment in runoff from feedlot surfaces containing varying amounts of unconsolidated surface material (USM), and (2) determine the effects of varying runoff rate on erosion and sediment size distribution. Simulated rainfall was applied to 0.75 m wide by 2 m long plots located within feedlot pens. Sieve and pipette analyses were used to measure the diameters of the eroded materials. No significant differences in runoff and erosion were found …

Multiple-View Planetary Photogrammetry And Its Visualization, Kyle D. Husmann

Electrical Engineering

During the summer of 2010, Dr. Taemin Kim and Kyle Husmann jointly developed a novel new algorithm to generate topographical maps of planetary surfaces using a multiple-view photogrammetry approach. To evaluate and debug the algorithm, a program called mvpgui was developed to visualize and examine the objective function. After verifying the correct operation of the algorithm and mvpgui with synthetic data, it is run with real orbital data from the Apollo 15 mission. The results confirm the validity of the multiple-view algorithm as well as demonstrate the value of objective function visualization.

Correlations Of Capacitance-Voltage Hysteresis With Thin-Film Cdte Solar Cell Performance During Accelerated Lifetime Testing, David S. Albin, Joseph A. Del Cueto

Publications (E)

In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 ºC.

Use Of 2nd And 3rd Level Correlation Analysis For Studying Degradation In Polycrystalline Thin-Film Solar Cells, David S. Albin, Joseph A. Del Cueto, S. H. Demtsu, S. Bansal

Publications (E)

The correlation of stress-induced changes in the performance of laboratory-made CdTe solar cells with various 2^nd and 3^rd level metrics is discussed. The overall behavior of aggregated data showing how cell efficiency changes as a function of open-circuit voltage (V_oc), shortcircuit current density (J_sc), and fill factor (FF) is explained using a two-diode, PSpice model in which degradation is simulated by systematically changing model parameters. FF shows the highest correlation with performance during stress, and is subsequently shown to be most affected by shunt resistance, recombination and in some cases voltage-dependent collection. Large decreases …

Effect Of Hysteresis On Measurements Of Thin-Film Cell Performance, David S. Albin, Joseph A. Del Cueto

Publications (E)

Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (V_oc), up to 10 mV, and smaller short-circuit current density (J_sc), by up to 2 mA/cm², relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be …

High Efficiency, Low Cost Solar Cells Manufactured Using ‘Silicon Ink’ On Thin Crystalline Silicon Wafers October 2009 - November 2010, Homer Antoniadis

Publications (E)

The objectives of Phase I (Feb – Oct 2009) include the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Sil-icon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to …

Hybrid Cooling Systems For Low-Temperature Geothermal Power Production, Andrea Ashwood, Desikan Bharathan

Publications (E)

The overall objective of this investigation is to identify and evaluate methods by which the net power output of an air-cooled geothermal power plant can be enhanced during hot ambient conditions using minimal amounts of water.

Geothermal power plants that use air-cooled heat rejection systems experience a decrease in power production during hot periods of the day. This decrease in power output typically coincides with the time when utilities need power to address high air conditioning loads. Hybrid cooling options, which use both air and water, have been studied for this report to assess how they might mitigate the net …

Modeling Of Cfrp-Concrete Interface Subjected To Coupled Pull-Out And Push-Off Actions, Tayyebeh Mohammadi, Baolin Wan, Jian-Guo Dai

Civil and Environmental Engineering Faculty Research and Publications

This paper presents a finite element (FE) modeling method for predicting the IC debonding failure when the FRP/concrete interface is subjected to coupled pull-out (shear) and push-off (dowel) actions. Damaged plasticity model was used to simulate the behavior of concrete close to FRP/concrete interface. A thin damage band exposed to mixed-mode loading condition was modeled separately along the FRP-concrete interface. Cohesive elements were used to model the FRP/concrete interface. A sensitivity analysis was performed to find the appropriate damaged band dimensions, bending stiffness of FRP, and tensile strength of concrete for the model. The numerical results were validated by the …

Standardization For Retail Facility Layout For Patagonia, Inc., Derek King

Industrial and Manufacturing Engineering

The purpose of this project is to create a standard layout for Patagonia retail stores. Currently, Patagonia has no standard layouts to follow when they update or open a new store; this has resulted in improper layouts and not fulfilling customers’ needs. This project will develop a way for Patagonia to solve both of these problems based on statistical engineering. The outcome of this project will result in a standard way for determining the optimal layout for new or updated Patagonia retail stores while meeting the business needs of the location.

Hardy Diagnostics Facility Redesign, Jamie W. Lam

Industrial and Manufacturing Engineering

This senior project is a facilities design for the plate production room at Hardy Diagnostics. This project was completed using a systematic layout planning approach. The main reason for this redesign was to consolidate all plate line production into one room. This would ensure better visability for the managers. After the project was defined, the different departments were established and the relationships between those departments were found. The space requirements needed for those departments were then measured out to also include the aisle widths and any machinery or carts needed to complete each function. Having determined all requirements for this …

A Cooperative Diversity-Based Robust Mac Protocol In Wireless Ad Hoc Networks, Sangman Moh, Chansu Yu

Electrical and Computer Engineering Faculty Publications

In interference-rich and noisy environment, wireless communication is often hampered by unreliable communication links. Recently, there has been active research on cooperative communication that improves the communication reliability by having a collection of radio terminals transmit signals in a cooperative way. This paper proposes a medium access control (MAC) algorithm, called Cooperative Diversity MAC (CD-MAC), which exploits the cooperative communication capability of the physical (PHY) layer to improve robustness in wireless ad hoc networks. In CD-MAC, each terminal proactively selects a partner for cooperation and lets it transmit simultaneously so that this mitigates interference from nearby terminals, and thus, improves …

Me-Em Enewsbrief, March 2011, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Accurate Six-Band Nearest-Neighbor Tight-Binding Model For The Π-Bands Of Bulk Graphene And Graphene Nanoribbons, Timothy B. Boykin, Mathieu Luisier, Gerhard Klimeck, Xueping Jiang, Neerav Kharche, Yu Zhou, Saroj K. Nayak

Birck and NCN Publications

Accurate modeling of the ␣-bands of armchair graphene nanoribbons (AGNRs) requires correctly reproducing asymmetries in the bulk graphene bands as well as providing a realistic model for hydrogen passivation of the edge atoms. The commonly used single-pz orbital approach fails on both these counts. To overcome these failures we introduce a nearest-neighbor, three orbital per atom p/d tight-binding model for graphene. The parameters of the model are fit to first-principles density-functional theory (DFT) – based calculations as well as to those based on the many-body Green’s function and screened-exchange (GW) formalism, giving excellent agreement with the ab initio AGNR bands. …

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

Bioelectrics Publications

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

Probabilistic Fault Displacement Hazard Analysis For Reverse Faults And Surface Rupture Scale Invariance, Zachary E. Ross

Master's Theses

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A methodology is presented for evaluating the potential surface fault displacement on reverse faults in a probabilistic manner. This methodology follows the procedures put forth for Probabilistic Fault Displacement Hazard Analysis (PFDHA). Empirical probability distributions that are central to performing a PFDHA are derived from field investigations of reverse faulting events. Statistical analyses are used to test previously assumed properties of scale invariance with respect to magnitude for normalized displacement. It is found that normalized displacement is statistically invariant with respect to magnitude and focal mechanism, allowing for the …

Predicting Articular Cartilage Constituent Material Properties Following In Vitro Growth Using A Proteoglycan-Collagen Mixture Model, Michael Stender

Master's Theses

      A polyconvex continuum-level  proteoglycan Cauchy stress function was developed based on the continuum electromechanical Poisson-Boltzmann unit cell model for proteoglycan interactions. The resulting proteoglycan model was combined with a novel collagen fibril model and a ground substance matrix material to create a polyconvex constitutive finite element model of articular cartilage. The true collagen fibril modulus , and the ground substance matrix shear modulus , were varied to obtain the best fit to experimental tension, confined compression, and unconfined compression data for native explants and explants cultured in insulin-like growth factor-1 (IGF-1) and transforming growth factor-β1 (TGF-β1).  Results indicate …

The State Of Software Engineering Maturity And Licensure, Travis Lawrence Dean

Master's Theses

IEEE-CS is pursuing licensing for software engineers, but ACM believes that software engineering is too immature, and regulating the profession would be premature. In 1996, Norman Gibbs and Gary Ford from Carnegie Mellon University performed a qualitative survey of the maturity of the software engineering profession. I apply this model to the present state of the art in software engineering and analyze the results for 2010. I analyze the maturity of software engineering to determine that the profession is not yet ready for licensure. This is not because the infrastructure of software engineering is too immature, but because we have …

Mitigating Moisture Susceptibility In Hot-Mix Asphalt Concrete, Tom P. Nguyen

Master's Theses

Moisture damage in asphalt pavement has always been a problem for drivers, bicyclists, and pedestrians. The primary objective of this study is to evaluate moisture susceptibility of Hot-Mix Asphalt (HMA) and to investigate mitigation techniques using different antistripping agents. Three types of antistripping agents were used in this research investigation. Two of which are chemical based and the other is hydrated lime. The two types of liquid antistripping agents used in this study include Arr Maz CC LOF-6500 and Arr Maz CC XL-9000. These two liquid antistripping agents were tested at 0.25%, 0.50%, and 0.75%. Hydrated Lime was tested at …

Influence Of Nozzle Pressure, Standoff Distance, And Reinforcing Steel Cage On Water Jetting Of Cidh Pile Anomalies, Matthew Jason Schaffer

Master's Theses

The effectiveness of removing anomalous material from cast-in-drilled-hole (CIDH) piles by water jetting was examined.  The primary objectives of this research were to examine how reinforcing steel influences water jetting and to evaluate how jetting pressures and standoff distance from the material surface affect water jetting of concrete type materials and PVC tubing.  The experimental work consisted of water blasting submerged test specimens using rotary jets, nozzles, pumping equipment, and testing procedures currently used in construction practice.  The concrete test specimens were comprised of ring- and cylinder-shaped samples, containing materials with compressive strengths of approximately 160 and 3,600 psi.  Typical …

Tower-Tracking Heliostat Array, Joel T. Masters

Master's Theses

This thesis presents a method of tracking and correcting for the swaying of a central receiver tower in concentrated solar production plants.  The method uses a camera with image processing algorithms to detect movement of the center of the tower.  A prototype was constructed utilizing a CMOS camera connected to a microcontroller to control the movements of three surrounding heliostats.  The prototype uses blob-tracking algorithms to detect and correct for movements of a colored model target.  The model was able to detect movements in the tower with average error of 0.32 degrees, and was able to correctly orient the surrounding …

Artificial Neural Networking As A Decision Tool For Natural Gas Investment, Micah D. Denecour

Master's Theses

With the growing interest in the Marcellus Shale and its natural gas deposits, there are opportunities to purchase and hold land for investment purposes. A robust decision tool is needed to help guide investors towards the most profitable properties. Artificial neural networks have many unique benefits that make them an ideal candidate for this purpose.

The artificial neural networks created in this study had nine independent variables. Combinations of these nine variables were created to describe 300 theoretical properties available for purchase. Each of these properties were then evaluated by an expert in the field and given a score from …

Integration Of Aeroservoelastic Properties Into The Nasa Dryden F/A-18 Simulator Using Flight Data From The Active Aeroelastic Wing Program, Alexander Wong Chin

Master's Theses

Aircraft structures have varying stiffness levels making them flexible. Consequently, this elastic property becomes increasingly important at high speeds affecting the flight dynamics of the aircraft.  In high speed aircraft such as the F/A-18, elastic structural properties must be accounted for to ensure confidence in predicted flight dynamics in order to avoid adverse aeroelastic phenomena throughout flight.

Data from the F/A-18 Active Aeroelastic Wing (AAW) program was used to create aeroservoelastic (ASE) models at varying flight conditions. The discretized ASE models were integrated into the NASA Dryden F/A-18 simulator in parallel with the traditional 6-DOF (degrees-of-freedom) flight dynamics calculations to …

Development Of High-Resolution Underwater Mapping Techniques, Christopher N. Roman, Gabrielle Inglis, J. Ian Vaughn, Stefan Williams, Oscar Pizarro, Ariell Friedman, Daniel Steinberg

Graduate School of Oceanography Faculty Publications

No abstract provided.

Exploration Of The Kolumbo Volcanic Rift Zone, Steven Carey, Katherine L. Croff Bell, Paraskevi Nomikou, Georges Vougioukalakis, Christopher N. Roman, Kathleen Cantner, Konstantina Bejelou, Maria Bourbouli, Julie Fero Martin

Graduate School of Oceanography Faculty Publications

No abstract provided.