Engineering Commons^™

Assimilation Of Tracking Technology In The Supply Chain, Rahul Basole, Maciek Nowak

Information Systems and Operations Management: Faculty Publications & Other Works

While tracking technology has become increasingly accessible, firms still struggle with deploying these technologies into the supply chain. Using the complementary perspectives of transaction cost and institutional theory, we develop an understanding of how supply network, product, and environmental characteristics jointly impact tracking technology assimilation. We empirically test our model on a global dataset of 535 supply chain executives and decision makers. The results suggest that assimilation is frequently initiated by an external stakeholder in a firm's supply chain and that firms must develop strong collaborative ties with their partners in order to take full advantage of this technology.

Experimental Analysis Of Catalytic Gasification Of Waste Polymers, Samuel O. Sanya, Uc Obiako, Aliandra Barbutti, Stephen Reeves, Eric M. Lange, Jade Moten

Undergraduate Research Posters 2017

This research focuses on advancing the current knowledge of a catalytic gasification process as a potential in-situ resource utilization and waste management system. This research has significance in a variety of engineering applications, but is of particular relevance towards municipal waste management and advancing space exploration. In this technology, typically referred to as Trash to Supply Gas (TtSG), liquid phase oxidation reactions produce carbon monoxide, carbon dioxide, and water. The oxidation reactions are complemented by two gas-phase reactions: the Water Gas Shift (WGS) and the Sabatier (or methanation) reaction, the main stages in the pathway of producing hydrogen and methane …

P2: Image Analysis And Quantification Of 3d Cancer Cell Migration, Stephen Hong, Alexander Roth

Undergraduate Research Posters 2017

Metastatic tumors are known for their ability to migrate toward circulatory apparatus and detach from the primary tumor. Generally, metastasis is quantified in vitro using migration assays that are normally measured in two dimensions (2D). Threedimensional (3D) migration assays can better mimic cancers by providing similar microenvironments to those observed in vivo. Imaging 3D cell cultures requires multiple 2D images stacked along a Z-axis; however, imaged cells would be in-focus at varied z-positions at different time points due to the characteristics of cell migration. Our goal in this study was to analyze in-focus cell images and quantify cell migration in …

P1: Dispersion And Characterization Of Boron Nitride Nanotubes Stabilized By Dna, Camerin Mcdonald

Undergraduate Research Posters 2017

Boron nitride nanotubes (BNNTs) are newly emerging nanomaterials with extraordinary mechanical properties as well as thermal and chemical stability. There have been growing interests in both fundamental studies and technological development of BNNTs such as protective coatings for high temperature and hazardous environments due to recent success in large scale synthesis of BNNTs. In this work, various DNA sequences were utilized to stabilize aqueous dispersions of BNNTs. First, we determined the optimum mass ratio of 1:1 for BNNTs:DNA using (GT)20 by UV-vis absorbance measurements. Second, the DNA length effect on the dispersion yield of BNNTs was investigated using sequences (GT)3, …

Transcutaneous Electrical Stimulation For The Production Of Functional Motion Of A Human Arm, Kyra Ruby

Undergraduate Research Posters 2017

Persons with tetraplegia experience little to no function in their arms and are therefore unable to perform reaching tasks without assistance. While functional electrical stimulation (FES) has shown promise for restoring motion to paralyzed limbs, it is limited by issues such as muscle fatigue and atrophy. A control strategy robust enough to overcome these issues has yet to be developed and some motions are not feasible even with the most sophisticated FES control strategy. In theory, a powered exoskeleton could be used in concert with an FES system to increase the accuracy of control and assist the arm when motions …

Ferroelectricity And The Phase Transition In Large Area Evaporated Vinylidene Fluoride Oligomer Thin Films, Keith Foreman, Shashi Poddar, Stephen Ducharme, Shireen Adenwalla

Shireen Adenwalla Papers

Organic ferroelectric materials, including the well-known poly(vinylidene fluoride) and its copolymers, have been extensively studied and used for a variety of applications. In contrast, the VDF oligomer has not been thoroughly investigated and is not widely used, if used at all. One key advantage the oligomer has over the polymer is that it can be thermally evaporated in vacuum, allowing for the growth of complex heterostructures while maintaining interfacial cleanliness. Here, we report on the ferroelectric properties of high-quality VDF oligomer thin films over relatively large areas on the order of mm². The operating temperature is identified via …

Defect Engineering: A Path Toward Exceeding Perfection, Hamed Attariani, Kasra Momeni, Kyle R. Adkins

Mechanical and Materials Engineering Faculty Publications

Moving to nanoscale is a path to get perfect materials with superior properties. Yet defects, such as stacking faults (SFs), are still forming during the synthesis of nanomaterials and, according to common notion, degrade the properties. Here, we demonstrate the possibility of engineering defects to, surprisingly, achieve mechanical properties beyond those of the corresponding perfect structures. We show that introducing SFs with high density increases the Young’s Modulus and the critical stress under compressive loading of the nanowires above those of a perfect structure. The physics can be explained by the increase in intrinsic strain due to the presence of …

Four-Terminal Square Piezoresistive Sensors For Mems Pressure Sensing, Awlad Hossain, Ahsan Mian

Mechanical and Materials Engineering Faculty Publications

The sensitivity of four-terminal piezoresistive sensors commonly referred to as van der Pauw (VDP) structure is investigated. The VDP sensor is considered to be fabricated on (100) silicon due to its potential application in MEMS (microelectromechanical systems) pressure sensors. The sensitivity of the VDP sensor may be affected by misalignment during the etching/diffusion process, the nonuniformity of piezoresistive coefficients through the sensor thickness, and pad size with respect to the sensor size. For this particular analysis, the effect of VDP stress sensitivity on variations in pad sizes and through-the-thickness -coefficient variation are studied as the effect of misalignment has already …

Computational Modeling Of A Williams Cross Flow Turbine, Sajjan Pokhrel

Browse all Theses and Dissertations

Hydropower is not only the most used renewable energy source in the United States, but in the world. While it is well known that large hydropower facilities, like the Hoover Dam, provide large amounts of electrical power, there is also a tremendous opportunity for hydroelectric power generation from small scale facilities that has largely been overlooked. The work being presented here studies a new cross flow turbine called the Williams Cross Flow Turbine (WCFT), which was designed to extract electric energy from low head, run-of-the-river, small hydropower sites. To spur the implementation of the WCFT in small hydropower applications, and …

Graduate School Of Engineering And Management Catalog 2017-2018, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication.

Computer Science Technology Education: An Incredible Explosion, Iwasan D. Kejawa

School of Computing: Faculty Publications

This paper explore what computers are, their usages and their functionalities. Computers can be used to learn or comprehend the understanding of all subjects, be it physics aerobics, swimming, biology, mathematics, agriculture, chemistry, business administration or commerce, just to name a few. In education, computers are used to project information to individuals in the classrooms or anywhere education is taking place, in churches, homes, schools, conference halls and so on. It is also used to convey the logic of a subject or behind a topic. Computers play an important role in educating our mind. With the usage of computers, we …

Specular Reflection Reduction By Metasurface Based On Parameteradjustable Meta-Atoms, Jianxun Su, Yao Lu, Hui Zhang, Zengrui Li, Yaoqing Lamar Yang ., Yongxing Che, Kainan Qi

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, an ultra-wideband, wide angle and polarization-insensitive metasurface is designed, fabricated, and characterized for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultra-wideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle swarm optimization (PSO) algorithm, the selection and distribution of the basic meta-atoms are optimized simultaneously to obtain the ultra-wideband diffusion scattering patterns. The metasurface can achieve an excellent RCS reduction in an ultra-wide …

Ultra-Wideband, Wide Angle And Polarization-Insensitive Specular Reflection Reduction By Metasurface Based On Parameteradjustable Meta-Atoms, Jianxun Su, Yao Lu, Hui Zhang, Zengrui Li, Yaoqing Lamar Yang, Yongxing Che, Kainan Qi

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, an ultra-wideband, wide angle and polarization-insensitive metasurface is designed, fabricated, and characterized for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultra-wideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle swarm optimization (PSO) algorithm, the selection and distribution of the basic meta-atoms are optimized simultaneously to obtain the ultra-wideband diffusion scattering patterns. The metasurface can achieve an excellent RCS reduction in an ultra-wide …

High-Speed Adaptive Wireless Body Area Networks, Miftadi Sudjai, Le Chung Tran, Farzad Safaei, Tadeusz Wysocki, Son Lam Phung

Department of Electrical and Computer Engineering: Faculty Publications

Adaptive ultra-wideband wireless body area network (WBAN) is proposed in this paper as a feasible mobile health platform, offering a high-speed and robust service. It employs a space-time-frequency-coded (STFC) multiband orthogonal frequency division multiplexing ultra-wideband technology. It is designed to improve the average bit error performance for high data rate applications while maintaining a reasonably high throughput in body-to-external links of a WBAN. The proposed adaptive WBAN comprises two novel components, namely, the frame transmission model and the bit error rate (BER) estimation-based adaptive algorithm. In addition, the optimization of adaptive parameters is conducted to obtain an extra improvement, hence …

Identification And Characterization Of Irregular Consumptions Of Load Data, Desh Deepak Sharma, S. N. Singh, Jeremy Lin, Elham Foruzan

Department of Electrical and Computer Engineering: Faculty Publications

The historical information of loadings on substation helps in evaluation of size of photovoltaic (PV) generation and energy storages for peak shaving and distribution system upgrade deferral. A method, based on consumption data, is proposed to separate the unusual consumption and to form the clusters of similar regular consumption. The method does optimal partition of the load pattern data into core points and border points, high and less dense regions, respectively. The local outlier factor, which does not require fixed probability distribution of data and statistical measures, ranks the unusual consumptions on only the border points, which are a few …

Anisotropy, Phonon Modes, And Lattice Anharmonicity From Dielectric Function Tensor Analysis Of Monoclinic Cadmium Tungstate, Alyssa Mock, Rafal Korlacki, Sean Knight, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We determine the frequency dependence of four independent Cartesian tensor elements of the dielectric function for CdWO₄ using generalized spectroscopic ellipsometry within mid-infrared and far-infrared spectral regions. Different single crystal cuts, (010) and (001), are investigated. From the spectral dependencies of the dielectric function tensor and its inverse we determine all long-wavelength active transverse and longitudinal optic phonon modes with A_u and B_u symmetry as well as their eigenvectors within the monoclinic lattice. We thereby demonstrate that such information can be obtained completely without physical model line-shape analysis in materials with monoclinic symmetry. We then augment the …

Shielding Effectiveness Performance Of Conductive Concrete Structures, Lim Nguyen, Aaron Krause, Christopher Tuan, Joel D. Blasey, Holly Mcnerney, Ferdinand J. Metzger

Department of Electrical and Computer Engineering: Faculty Publications

Conductive concrete mixtures have been designed and demonstrated to perform electromagnetic shielding. This paper describes the design, testing methods, and results obtained from the development of conductive concrete construction for structured electromagnetic shielding.

Integrated Mid-Infrared, Far Infrared And Terahertz Optical Hall Effect (Ohe) Instrument, And Method Of Use, Tino Hofmann, Mathias M. Schubert, Stefan Schoeche, Sean Knight, Craig M. Herzinger, John A. Woollam, Greg K. Pribil, Thomas E. Tiwald

Department of Electrical and Computer Engineering: Faculty Publications

System Stage, and Optical Hall Effect (OHE) system method for evaluating such as free charge carrier effective mass, concentration, mobility and free charge carrier type in a (51) Int. Ci. sample utilizing a permanent magnet at room temperature.

Systems And Methods Using Drawings Which Incorporate Bometric Data Assecurity Information, Cliff Xiaongang Wang, Wesley E. Snyder, Benjamin S. Riggan

Department of Electrical and Computer Engineering: Faculty Publications

Systems and method using drawings as security information are disclosed. According to an aspect, a computing device may include a touchscreen display configured to receive information for drawing a security manager configured to determined one or more characteristics associated with input of the gesture information. The security manager may also be configured to authenticate a user based on the drawn security picture and the one or more characteristics associated with input of the gesture information.

A System To Monitor Segmental Intracellular, Interstitial, And Intravascular Volume And Circulatory Changes During Acute Hemodialysis, Leslie Montgomery, Richard Montgomery, Wayne Gerth, Marty Loughry, Susie Q. Lew, Manuel T. Velasquez

Medicine Faculty Publications

This paper describes a new combined impedance plethysmographic (IPG) and electrical bioimpedance spectroscopic (BIS) instrument and software that allows noninvasive real-time measurement of segmental blood flow and changes in intracellular, interstitial, and intravascular volumes during various fluid management procedures. The impedance device can be operated either as a fixed frequency IPG for the quantification of segmental blood flow and hemodynamics or as a multi-frequency BIS for the recording of intracellular and extracellular resistances at 40 discrete input frequencies. The extracellular volume is then deconvoluted to obtain its intra-vascular and interstitial component volumes as functions of elapsed time. The purpose of …

Underground Structures, Rock Structures And Rock Mechanics From Ancient Era To The Modern Age, Ebru Akiş, Özgür Satici

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Usage of underground space is an old habit for human beings since ancient era. Our ancestors have used caves as a shelter for protection from the wildlife and nature, and they excavated caves to extract valuable minerals. They also used them as sanctuaries, tombs or for storage of goods. In addition, they built tunnels to be used as assault systems or to underpass fortifications during ancient warfare. Later on, tunnels were driven to supply water to the towns or to protect the towns from floods. They also built them for communication purposes. Though not knowing the exact time when they …

Novel Environmentally Benign Hydrogel: Nano-Silica Hybrid Hydrolyzed Polyacrylamide/ Polyethyleneimine Gel System For Conformance Improvement In High Temperature High Salinity Reservoir, Liping Ma, Shitou Wang, Yifu Long, Changqian Zhu, Hongbin Yang, Tangying Yang, Xiaochun Liu, Xiaorong Li, Baojun Bai, Wanli Kang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In order to address the conformance problem in high temperature and high salinity/hardness reservoir, an environmentally benign in-situ gel was developed based on hydrolyzed polyacrylamide (HPAM) and polyethyleneimine (PEI). Moreover, silica nanoparticle (SNP) was embedded to improve the performance of HPAM/PEI gel. To achieve the optimum formulation of HPAM/PEI-SNP gel, a comprehensive investigation was first conducted with the respect of gelation time, gel strength, and thermal stability. In addition, the particle size of SNP was determined by Dynamic Light Scatter (DLS) and the microstructure of HPAM/ PEI-SNP gel was characterized via Scanning Electron Microscopy (SEM). The optimum formulation, containing the …

Influence Of Moisture Content Distribution In Soil On Pavement And Geothermal Energy, Md Adnan Khan

Doctoral Dissertations

Moisture content in soil has a great implication in engineering design, and it has been heavily investigated by soil engineers and scientists. If moisture content in expansive soil changes drastically, it will create significant volume change in the soil. If expansive soil is present in building foundation or pavement subgrade, it may result in structural failure. On the other hand, if sufficient moisture content is present in soil, it will increase the production of geothermal energy from the ground soil. This dissertation is an effort to understand the effects of moisture content on both expansive soils and geothermal energy that …

Design, Modeling, Fabrication, And Testing Of A Multistage Micro Gas Compressor With Piezoelectric Unimorph Diaphragm And Passive Microvalves For Microcooling Applications, Shawn Thanhson Le

Doctoral Dissertations

This dissertation investigates the development of a multistage micro gas compressor utilizing multiple pump stages cascaded in series to increase the pressure rise with passive microvalves and piezoelectric unimorph diaphragms. This research was conducted through modeling, simulation, design, and fabrication of the microcompressor and its components. A single-stage and a two-stage microcompressor were developed to demonstrate and compare the performance and effectiveness of using a cascaded multistage design.

Steady fluid flow through static microvalves structure was studied to gain insight on its gas flow dynamics and characteristics. Transient analysis combined with the structure's interaction was investigated with an analytical model …

A Study Of Mathematics Achievement, Placement, And Graduation Of Engineering Students, Sara Hahler Blazek

Doctoral Dissertations

The purpose of this study was to determine how background knowledge impacts freshmen engineering students' success at Louisiana Tech University in terms of grades in two different freshman classes and graduation. To determine what factors impact students, three different studies were implemented. The first study used linear regression to analyze which demographic and academic variables significantly impacted freshman math and engineering courses. Using regression discontinuity, the second study determined if the university's placement requirement for Pre-Calculus was appropriate. The final study analyzed factors that impact graduation for engineering students as well as other disciplines to determine which significant variables were …

Expanding The Applications Of Poly(Dimethylsiloxane) In Biomicrofluidics, Sawyer D. Stone

Doctoral Dissertations

This work aims to create novel applications for poly(dimethylsiloxane) (PDMS) in the field of biomicrofluidics through oxidative stress detection, doping of the polymer for intentional leaching into microdevices, and the development of low-cost implements for fabricating PDMS microfluidic devices. PDMS has become the polymer of choice for research in microfluidics due to its optical clarity, ease of fabrication, flexibility in design, good mechanical properties, and the ability to chemically modify the surface.

Biomicrofluidics enables the rapid throughput and analysis of small biological samples requiring less time investment and reagent use than traditional macroscale laboratory techniques. Polymer devices are inexpensive, easily …

A Stationary Camera For Use With Other Implantable Medical Devices, Ariane Garrett

Holster Scholar Projects

I designed an optical system for analysis of implantable devices. The final system consists of a 3mm double convex lens that focuses a light spot onto a tissue or implantable medical device. This light spot can then provide feedback on the movement of flow through a device or the development of tissue on the device, although my project focused solely on the flow application. The light spot is generated by an LED and directed using a half mirror. It is then focused using a ball lens, fiber optic, and the double convex lens. With this system the generated light spot …

Tuned Liquid Column Damper Based Reduction Ofic Dynamresponses Of Scaled Offshore Platforms In Different Ocean Wave Basins, Deirdre O’Donnel, Jimmy Murphy, Cian Desmond, Vesna Jaksic, Vikram Pakrashi

Conference Papers

Control of dynamic responses of renewable energy device platforms is important for their performance, safe operation and efficiency over their lifetime under regular and extreme wave conditions. Tuned Liquid Column Dampers (TLCDs) have been recently considered as a viable passive control mechanism in this regard but limited information is available in relation to their experimental performance. This paper compares scaled experiments conducted in two different ocean wave basins where floating offshore platforms were retrofitted with multiple TLCDs (MTLCDs). Performance of such MTLCDs in these scaled ocean wave basins are evaluated and compared considering control of dynamic responses for a specific …

Experimental Study Of Corrugated Metal-Composite Tubes Under Axial Loading, Arameh Eyvazian, Hozhabr Mozafari, Abdel Magid Hamouda

Department of Mechanical and Materials Engineering: Faculty Publications

In this study, crushing behavior of corrugated metal-composite tube was examined experimentally under axial loading condition. Six types of specimens, classified into two groups of metal and metal-composite, were tested under quasi static axial loading. The failure mechanism and failure history of the specimens were presented and discussed. The experimental result showed that corrugated metal composite tubes demonstrate perfect energy absorption characteristics in terms of uniformity of load-displacement diagram, reduction of initial peak load and controlling failure mechanism. Moreover, it was also found that adding filament wound layer of composite on the surface of metallic corrugated tube compensated weakness of …

Disturbed Cyclical Stretch Of Endothelial Cells Promotes Nuclear Expression Of The Pro-Atherogenic Transcription Factor Nf-Kb, Ryan M. Pedrigi, Konstantinos I. Papadimitriou, Avinash Kondiboyina, Sukhjinder Sidhu, James Chau, Miten B. Patel, Daniel C. Baeriswyl, Emmanuel M. Drakakis, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

Exposure of endothelial cells to low and multidirectional blood flow is known to promote a pro-atherogenic phenotype. The mechanics of the vessel wall is another important mechano-stimulus within the endothelial cell environment, but no study has examined whether changes in the magnitude and direction of cell stretch can be pro-atherogenic. Herein, we developed a custom cell stretching device to replicate the in vivo stretch environment of the endothelial cell and examined whether low and multidirectional stretch promote nuclear translocation of NF-kB. A fluid–structure interaction model of the device demonstrated a nearly uniform strain within the region of cell attachment and …