Engineering Commons^™

Material Specific Load Combination Factors For Option 2 Fad Curves, Matt Saxon Schaser

ETD Archive

No abstract provided.

Ennet: Inferring Large Gene Regulatory Networks From Expression Data Using Gradient Boosting, Janusz Slawek, Tomasz Arodź

Computer Science Publications

Background

The regulation of gene expression by transcription factors is a key determinant of cellular phenotypes. Deciphering genome-wide networks that capture which transcription factors regulate which genes is one of the major efforts towards understanding and accurate modeling of living systems. However, reverse-engineering the network from gene expression profiles remains a challenge, because the data are noisy, high dimensional and sparse, and the regulation is often obscured by indirect connections.

Results

We introduce a gene regulatory network inference algorithm ENNET, which reverse-engineers networks of transcriptional regulation from a variety of expression profiles with a superior accuracy compared to the state-of-the-art …

An Entropy-Based Automated Cell Nuclei Segmentation And Quantification: Application In Analysis Of Wound Healing Process, Varun Oswal, Ashwin Belle, Robert Diegelmann, Kayvan Najarian

Computer Science Publications

The segmentation and quantification of cell nuclei are two very significant tasks in the analysis of histological images. Accurate results of cell nuclei segmentation are often adapted to a variety of applications such as the detection of cancerous cell nuclei and the observation of overlapping cellular events occurring during wound healing process in the human body. In this paper, an automated entropy-based thresholding system for segmentation and quantification of cell nuclei from histologically stained images has been presented. The proposed translational computation system aims to integrate clinical insight and computational analysis by identifying and segmenting objects of interest within histological …

On Applications And Limitations Of One-Dimensional Capillarity Formulations For Media With Heterogeneous Wettability, T. M. Bucher, H. Vahedi Tafreshi

Mechanical and Nuclear Engineering Publications

Force-balance-based one-dimensional algebraic formulations that are often used in characterizing the capillarity of a multi-component system (e.g., predicting capillary height rise inporous media) are discussed. It is shown that such formulations fail to provide accurate predictions when the distribution of wetting (or non-wetting) surfaces is not homogeneous. A more general mathematical formulation is suggested and used to demonstrate that for media with heterogeneous wettability, hydrophilic (or hydrophobic) surfaces clustered in groups will have less contribution to the overall capillarity of the system.

Amelogenin Peptide Extract Increases Differentiation And Angiogenic And Local Factor Production And Inhibits Apoptosis In Human Osteoblasts, Rene Olivares-Navarrete, Sharon L. Hyzy, Argelia Almaguer-Flores, Corinna Mauth, Anja C. Gemperli, Barbara D. Boyan, Zvi Schwartz

Biomedical Engineering Publications

Enamel matrix derivative (EMD), a decellularized porcine extracellular matrix (ECM), is used clinically in periodontal tissue regeneration. Amelogenin, EMD’s principal component, spontaneously assembles into nanospheres in vivo, forming an ECM complex that releases proteolytically cleaved peptides. However, the role of amelogenin or amelogenin peptides in mediating osteoblast response to EMD is not clear. Human MG63 osteoblast-like cells or normal human osteoblasts were treated with recombinant human amelogenin or a 5 kDa tyrosine-rich amelogenin peptide (TRAP) isolated from EMD and the effect on osteogenesis, local factor production, and apoptosis assessed. Treated MG63 cells increased alkaline phosphatase specific activity and levels of …

Degradation In Algan/Gan Heterojunction Field Effect Transistors Upon Electrical Stress: Effects Of Field And Temperature, C. Y. Zhu, F. Zhang, Romualdo A. Ferreyra, U. Ozgur, Hadis Morkoç

Electrical and Computer Engineering Publications

AlGaN/GaN heterojunction field effect transistors (HFETs) with 2 μm gate length were subjected to on-state-high-field (high drain bias and drain current) and reverse-gate-bias (no drain currentand reverse gate bias) stress at room and elevated temperatures for up to 10 h. The resulting degradation of the HFETs was studied by direct current and uniquely phase noise before and after stress. A series of drain and gate voltages was applied during the on-state-high-field and reverse-gate-bias stress conditions, respectively, to examine the effect of electric field on degradation of the HFET devices passivated with SiNx. The degradation behaviors under these two types of …

The Effect Of Stair Case Electron Injector Design On Electron Overflow In Ingan Light Emitting Diodes, F. Zhang, X. Li, S. Hafiz, S. Okur, Vitaliy Avrutin, U. Ozgur, Hadis Morkoç, A. Matulionis

Electrical and Computer Engineering Publications

Effect of two-layer (In0.04Ga0.96N and In0.08Ga0.92N) staircase electron injector (SEI) on quantum efficiency of light-emitting-diodes (LEDs) in the context of active regions composed of single and quad 3 nm double heterostructures (DHs) is reported. The experiments were augmented with the first order model calculations of electron overflow percentile. Increasing the two-layer SEI thickness from 4 + 4 nm up to 20 + 20 nm substantially reduced, if not totally eliminated, the electron overflow in single DH LEDs at low injections without degrading the material quality evidenced by the high optical efficiency observed at 15K and room temperature. The improvement in …

Ultra-Low-Energy Non-Volatile Straintronic Computing Using Single Multiferroic Composites, Kuntal Roy

Electrical and Computer Engineering Publications

The primary impediment to continued downscaling of traditional charge-based electronic devices in accordance with Moore's law is the excessive energy dissipation that takes place in the device during switching of bits. One very promising solution is to utilize multiferroicheterostructures, comprised of a single-domain magnetostrictive nanomagnet strain-coupled to a piezoelectric layer, in which the magnetization can be switched between its two stable states while dissipating minuscule amount of energy. However, no efficient and viable means of computing is proposed so far. Here we show that such single multiferroic composites can act as universal logic gates for computing purposes, which we demonstrate …

Reliability Of Algan/Gan High Electron Mobility Transistors On Low Dislocation Density Bulk Gan Substrate: Implications Of Surface Step Edges, N. Killat, M. Montes Bajo, T. Paskova, K. R. Evans, J. Leach, X. Li, Ü. Özgür, Hadis Morkoç, K. D. Chabak, A. Crespo, J. K. Gillespie, R. Fitch, M. Kossler, D. E. Walker, M. Trejo, G. D. Via, J. D. Blevins, M. Kuball

Electrical and Computer Engineering Publications

To enable gaining insight into degradation mechanisms of AlGaN/GaN high electron mobility transistors, devices grown on a low-dislocation-density bulk-GaN substrate were studied. Gateleakage current and electroluminescence (EL) monitoring revealed a progressive appearance of EL spots during off-state stress which signify the generation of gate current leakage paths.Atomic force microscopy evidenced the formation of semiconductor surface pits at the failure location, which corresponds to the interaction region of the gate contact edge and the edges ofsurface steps.

Acoustically Assisted Spin-Transfer-Torque Switching Of Nanomagnets: An Energy-Efficient Hybrid Writing Scheme For Non-Volatile Memory, Ayan K. Biswas, Supriyo Bandyopadhyay, Jayasimha Atulasimha

Electrical and Computer Engineering Publications

We show that the energy dissipated to write bits in spin-transfer-torque random access memory can be reduced by an order of magnitude if a surface acoustic wave (SAW) is launched underneath the magneto-tunneling junctions (MTJs) storing the bits. The SAW-generated strain rotates the magnetization of every MTJs' soft magnet from the easy towards the hard axis, whereupon passage of a small spin-polarized current through a target MTJ selectively switches it to the desired state with > 99.99% probability at room temperature, thereby writing the bit. The other MTJs return to their original states at the completion of the SAW cycle.

Correlation Between Si Doping And Stacking Fault Related Luminescence In Homoepitaxial M-Plane Gan, S. Khromov, B. Monemar, Vitaliy Avrutin, Hadis Morkoç, L. Hultman, G. Pozina

Electrical and Computer Engineering Publications

Si-doped GaN layers grown by metal organic vapor phase epitaxy on m-plane GaN substrates were investigated by low-temperature cathodoluminescence (CL). We have observed stacking fault (SF) related emission in the range of 3.29–3.42 eV for samples with moderate doping, while for the layers with high concentration of dopants, no CL lines related to SFs have been noted. Perturbation of the SF potential profile by neighboring impurity atoms can explain localization ofexcitons at SFs, while this effect would vanish at high doping levels due to screening.

Microscopic Distribution Of Extended Defects And Blockage Of Threading Dislocations By Stacking Faults In Semipolar (1101)(1101)()(1101)() Gan Revealed From Spatially Resolved Luminescence, S. Okur, S. Metzner, N. Izyumskaya, F. Zhang, Vitaliy Avrutin, C. Karbaum, F. Bertram, J. Christen, Hadis Morkoç, Ü. Özgür

Electrical and Computer Engineering Publications

Spatial distribution of extended defects in semipolar -oriented GaN layers grown on patterned(001) Si substrates with striped grooves of varying width was investigated by optical means only using near-field scanning optical microscopy (NSOM) and cathodoluminescence (CL). A high density of basal and prismatic stacking faults was observed in the c⁻ wings, and the threadingdislocations in c+ wings, which appear as dark patterns in the NSOM and CL images, were found to bend toward the surface during the initial stages of growth. In the case when growingc+ front of GaN made contact with the SiO2 masking layer during growth, stacking …

Strain Induced Variations In Band Offsets And Built-In Electric Fields In Ingan/Gan Multiple Quantum Wells, L. Dong, J. V. Mantese, Vitaliy Avrutin, Ü. Özgür, H. Morkoç, S. P. Alpay

Electrical and Computer Engineering Publications

The band structure, quantum confinement of charge carriers, and their localization affect the optoelectronic properties of compound semiconductor heterostructures and multiple quantum wells (MQWs). We present here the results of a systematic first-principles based density functional theory (DFT) investigation of the dependence of the valence band offsets and band bending in polar and non-polar strain-free and in-plane strained heteroepitaxial In x Ga1- xN(InGaN)/GaN multilayers on the In composition and misfit strain. The results indicate that for non-polar m-plane configurations with [12¯10]InGaN // [12¯10]GaN and [0001]InGaN // [0001]GaN epitaxial alignments, the valence band offset changes linearly from 0 to 0.57 eV …

Enhanced Microwave Dielectric Tunability Of Ba0.5sr0.5tio3 Thin Films Grown With Reduced Strain On Dysco3 Substrates By Three-Step Technique, Hongrui Liu, Vitaliy Avrutin, Congyong Zhu, Ümit Özgür, Juan Yang, Changzhi Lu, Hadis Morkoç

Electrical and Computer Engineering Publications

Tunable dielectric properties of epitaxial ferroelectric Ba_0.5Sr_0.5TiO₃ (BST) thin films deposited on nearly lattice-matched DyScO₃ substrates by radio frequency magnetron sputtering have been investigated at microwave frequencies and correlated with residual compressive strain. To reduce the residual strain of the BST films caused by substrate clamping and improve their microwave properties, a three-step deposition method was devised and employed. A high-temperature deposition at 1068 K of the nucleation layer was followed by a relatively low-temperature deposition (varied in the range of 673–873 K) of the BST interlayer and a high-temperature deposition at 1068 K …

Spectral Distribution Of Excitation-Dependent Recombination Rate In An In0.13ga0.87n Epilayer, K. Jarašiūnas, S. Nargelas, R. Aleksiejūnas, S. Miasojedovas, M. Vengris, S. Okur, H. Morkoç, Ü Özgür, C. Giesen, Ö. Tuna, M. Heuken

Electrical and Computer Engineering Publications

Time-resolved optical techniques of photoluminescence (PL), light-induced transient grating(LITG), and differential transmission spectroscopy were used to investigate carrier dynamics in a single 50-nm thick In_0.13Ga_0.97N epilayer at high photoexcitation levels. Data in wide spectral, temporal, excitation, and temperature ranges revealed novel features in spectral distribution of recombination rates as follows: at low injection levels, an inverse correlation of carrier life time increasing with temperature and diffusivity decreasing with temperature confirmed a mechanism of diffusion-limited nonradiative recombination at extended defects. Carrier dynamics in the spectral region below the absorption edge but ∼70 meV above the PL band …

Optical Studies Of Strain And Defect Distribution In Semipolar (1(1)Over-Bar01) Gan On Patterned Si Substrates, N. Izyumskaya, F. Zhang, S. Okur, T. Selden, V. Avrutin, Ü. Özgür, S. Metzner, C. Karbaum, F. Bertram, J. Christen, H. Morkoç

Electrical and Computer Engineering Publications

Formation of defects in semipolar ( 11¯01 )-oriented GaN layers grown by metal-organic chemical vapor deposition on patterned Si (001) substrates and their effects on optical properties were investigated by steady-state and time-resolved photoluminescence (PL) and spectrally and spatially resolved cathodoluminescence (CL). Near-band edge emission is found to be dominant in the c +-wings of semipolar ( 11¯01 )GaN, which are mainly free from defect-related emission lines, while the c – wings contain a large number of basal stacking faults. When the advancing c+ and c — fronts meet to coalesce into a continuous film, the existing stacking faults contained …

Extending Device Performance In Photonic Devices Using Piezoelectric Properties, Gregory Edward Triplett

Electrical and Computer Engineering Publications

This study focuses on the influence of epi-layer strain and piezoelectric effects in asymmetric GaInAs/GaAlAs action regions that potentially lead to intra-cavity frequency mixing. The theoretical limits for conduction and valence band offsets in lattice-matched semiconductor structures have resulted in the deployment of non-traditional approaches such as strain compensation to extend wavelength in intersubband devices, where strain limits are related to misfit dislocation generation. Strain and piezoelectric effects have been studied and verified using select photonic device designs. Metrics under this effort also included dipole strength, oscillator strength, and offset of energy transitions, which are strongly correlated with induced piezoelectric …

Pseudomorphic Growth Of Inas On Misoriented Gaas For Extending Quantum Cascade Laser Wavelength, Gregory Edward Triplett, Charles Meyer, Emily Cheng, Justin Grayer, David Mueller, Denzil Roberts, Samuel Graham

Electrical and Computer Engineering Publications

The authors have studied the impact of epilayer strain on the deposition of InAs/GaAs on (100) and (111)B with 2 degrees offset toward 2-1-1 surfaces. Consequences of a 7% lattice mismatch between these orientations in the form of three-dimensional growth are less apparent for (111)B with 2 degrees offset toward 2-1-1 surfaces compared to (100). By exploring a range of molecular beam epitaxy process parameters for InAs/GaAs growth and utilizing scanning electron microscopy, atomic force microscopy, and Raman spectroscopy to evaluate the quality of these strained layers, the authors develop empirical models that describe the influence of the process conditions …

Where Next For Supply Chain Management?, Des Lee

Books/Book chapters

Supply chain management (SCM) has been so successful that it is largely taken for granted. Its success has been built on improving three key flows – of product, of money and of information – and on one core principle – core competence. What next for SCM? This article outlines the vulnerabilities that are embedded in modern supply chains and the unintended consequences of outsourcing activities that are not core competences. These consequences are global and have the potential to undermine past achievements. Finally, broad suggestions are made as to how these issues can be addressed and the areas on which …

Colloidal Nano-Apatite Particles With Active Luminescent And Magentic Properties For Biotechnology Applications, Rajendra Kasinath, Kumar Ganesan

Environmental Engineering

Colloidal Nano-apatite Particles with Active Luminescent and Magentic Properties for Biotechnology Applications. The synthesis of functional nano-materials is a burgeoning field that has produced remarkable and consistent breakthroughs over the last two decades. Individual particles have become smaller and shown potential for well defined functionality. However, there are still unresolved problems, a primary one being the loss of functionality and novelty due to uncontrolled aggregation driven by surface energy considerations. As such the first design criteria to harness the true potential of nanoparticles is to prevent unwanted agglomeration by: (1) improving, and, if possible, (2) controlling aggregation behavior. This requires …

San Antonio Condensate Collection And Use Manual For Commercial Buildings, Diana D. Glawe

Engineering Faculty Research

Condensate is an inherent byproduct of building HVAC systems. Since condensate is formed from moisture in the air, it is relatively high-quality water. Therefore, it can be collected and used on-site with relatively little treatment. Using condensate conserves municipal water and lowers energy costs associated with the municipal collection, treatment, and distribution of water that would otherwise be consumed.

Collecting condensate from commercial building heating, ventilation, and air-conditioning (HVAC) systems is relatively simple. Using condensate for on-site applications offers a potentially quick return on investment, especially in hot and humid climates. To help increase the implementation of condensate use, this …

Adequate Ventilation: How Is It Defined And Does It Adequately Warn Consumers?, Christopher Blankenship

Theses, Dissertations and Capstones

The purpose of this research was to clarify and define the term “adequate ventilation.” Upon looking at regulations, court cases, and other elements, it is clear that the term is inadequate to inform consumers and does not instruct consumers on how to achieve proper ventilation. To find out if consumers understand this, random persons were asked to define it. The answers were given a numerical value to show the knowledge trend. The outcome showed that most people do not understand how to achieve proper ventilation. Conclusion: Diagrams showing how to set up a room with ventilation and new instructions are …

A Multi-Objective Optimal Pid Control For A Nonlinear System With Time Delay, Furui Xiong, Zhichang Qin, Carlos Hernández, Yousef Sardahi, Yousef Narajani, Wei Liang, Yang Xue, Oliver Schütze, Jianqiao Sun

All Engineering Faculty Research

It is generally difficult to design feedback controls of nonlinear systems with time delay to meet time domain specifications such as rise time, overshoot, and tracking error. Furthermore, these time domain specifications tend to be conflicting to each other to make the control design even more challenging. This paper presents a cell mapping method for multi-objective optimal feedback control design in time domain for a nonlinear Duffing system with time delay. We first review the multi-objective optimization problem and its formulation for control design. We then introduce the cell mapping method and a hybrid algorithm for global optimal solutions. Numerical …

Examining Design Fixation In Engineering Idea Generation: The Role Of Example Modality, Vimal Viswanathan, Julie Linsey

Faculty Publications, Mechanical Engineering

Design fixation is a major concern in engineering idea generation because it restricts the solution space in which designers search for their ideas. For designers to be more creative, it is essential to mitigate their fixation. The majority of studies in the literature investigate the role of pictorial stimuli in design fixation; however, the role of examples presented in other formats, including physical prototypes, is largely unknown. This paper presents a study that compares design fixation, in novice designers, caused by pictorial and physical representations. The effects of defixating materials proposed by Linsey et al. (2010) are also investigated. The …

S-Stem Scholars, A Second Generation: Support For At-Risk Upper Division And Transfer Students In Ceas, Andrew A. Kline, Betsy M. Aller

Academic Leadership Academy

Begun in 2010, the S-STEM Scholar Program increases opportunities for financially needy but academically talented students. These students:

•Are first-time, first year students •Demonstrate financial need through FAFSA applications

•Will enter a major in the College of Engineering and Applied Sciences

•Have a math ACT of 24 or above

Student awardees receive up to $3,000 per semester, and continue to receive this amount for up to eight semesters with continued academic success and progress to degree.

The Effects Of Toning Shoes On The Postural Stability Of Women, Kevin Farley, Audrey Niverson, Renee Rogge

Rose-Hulman Undergraduate Research Publications

Postural stability is the ability to maintain an upright posture and to keep the center of pressure (COP) within the limits of the body’s base of support. It is maintained through the dynamic integration of muscle activity and joint position. The foot, and therefore footwear, also plays a critical role in postural stability. The goal of this study is to determine the effects of toning shoes on the postural stability of women.

An Investigation Of Thermal Imaging To Detect Physiological Indicators Of Stress In Humans, Carl Brady Cross

Browse all Theses and Dissertations

Real-time, stand-off sensing of humans to detect emotional state would be valuable in many defense, security and medical scenarios. Using a multimodal sensor platform that incorporates high-resolution visible-wavelength and mid-wave infrared cameras and a millimeter-wave (mmW) radar system, the detection of physiological indicators of psychological stress is tested through laboratory experiments. Our approach focuses on thermal imaging to measure temperature patterns in distinct facial regions representative of underlying hemodynamic patterns. Experiments were designed to: 1) determine the ability of thermal imaging to detect high levels of psychological stress and assess responses to physical versus psychological stressors; 2) evaluate the fidelity …

Off Muskegon 2013 Data, Grand Valley State University

Data

Data set concerning the 2013 season with the buoy located about 7 miles west of Muskegon, MI.

Modeling Tools For Conformal Orthotic Devices, Steven David Riddle

Open Access Theses

The purpose of this thesis is to advance the design of conformal orthotic devices through the development of two modeling tools to address knowledge gaps in the field.

The field of human orthotics has been continually troubled by identifying successful methods of harnessing devices to the body. Past orthotics have utilized a rigid framework with minimal degrees of freedom (DOFs) driven by hard actuators attached to the body at select anchor points. Many devices design the structure and anchor points such that they reduce the degrees of freedom of a targeted joint, limiting the user's mobility and often causing the …

Characterization Of Heat And Mass Transport In Magnesium Hydride Hydrogen Storage Systems, Jennifer Anne Dadson

Open Access Theses

Hydrogen systems can provide viable alternatives for satisfying the world's energy requirements that both reduce dependency on and are more environmentally friendly than fossil fuels. For vehicular systems for example, hydrogen storage systems must have adequate gravimetric and volumetric storage capacities in addition to rapid uptake and release. Magnesium hydride shows good potential as a solid state hydrogen storage media due to its high gravimetric storage capacity of 7.6 wt% H₂; the highest of all reversible metal hydrides. Drawbacks, however, are its large reaction enthalpy of 78 kJ/mol for the desorption reaction and its low thermal conductivity of …