Engineering Commons^™

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 …

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 …

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 …

Using Mediawiki, The Semantic Mediawiki Extension And Relfinder For Heritage Data Management: A Rock Art Case Study, Robert A. Haubt

Staff Scholarship - Australia & Dubai

This paper looks at the usefulness of the MediaWiki and relevant wiki extensions for rock art data management and research. The paper follows a framework provided by the Global Rock Art Database www.rockartdatabase.com and examines a new database model for a semantic data management approach. Through practical examples it explores the usefulness of wikis in the data management life cycle from data planning to collection, storage and dissemination and examines interconnections within each phase of the cycle. The paper proposes a combined use of the Semantic MediaWiki extension and the RelFinder for visualization of semantic relationships, which could assist researchers …

Development Of Nanostructured Austempered Ductile Cast Iron, Saranya Panneerselvam

Wayne State University Dissertations

Austempered Ductile Cast Iron is emerging as an important engineering materials in recent years because of its excellent combination of mechanical properties such as high strength with good ductility, good fatigue strength and fracture toughness together with excellent wear resistance. These combinations of properties are achieved by the microstructure consisting of acicular ferrite and high carbon austenite. Refining of the ausferritic microstructure will further enhance the mechanical properties of ADI and the presence of proeutectoid ferrite in the microstructure will considerably improve the ductility of the material.

Thus, the focus of this investigation was to develop nanostructured austempered ductile cast …

Bioreducible Layer-By-Layer Films For Gene Delivery, Lingxiao Xie

Wayne State University Dissertations

Layer-by-Layer (LbL) gene delivery system is fabricated by polycation and plasmid DNA alternative deposition based on electrostatic force between each other. This dissertation explored the relationship between LbL film assembly and disassembly. Demonstrated that the film disassemble process is closely related to film interior structure. LbL interlayer diffusion, which is caused by the polyelectrolytes own properties, such as polymer chain length, molecular weight, and charge density, can influence film growth mode. The interlayer diffusion is the main reason to lead fast and bulk DNA releasing of bioreducible LbL film. Preventing interlayer diffusion by inserting small diffusion coefficient polymer, such as …

Industrial Wireless Sensor Networks 2016, Qindong Sun, Schancang Li, Shanshan Zhao, Hongjian Sun, Li Xu, Arumugam Nallamathan

Information Technology & Decision Sciences Faculty Publications

The industrial wireless sensor network (IWSN) is the next frontier in the Industrial Internet of Things (IIoT), which is able to help industrial organizations to gain competitive advantages in industrial manufacturing markets by increasing productivity, reducing the costs, developing new products and services, and deploying new business models.

Laboratory X - Autonomous Vehicle Application, Nate Lant, Matthew Strong

Engineering Applications of GIS - Laboratory Exercises

Autonomous vehicles are currently the newest and hottest technology and show tremendous potential in making current transportation much more efficient. GIS is a key element in providing different mapping solutions and satellite assistance to support the cars in addition to their LIDAR and camera systems. Over the last few decades, different technologies have been integrated into cars to make them more user friendly--more autonomous. Recently, cars have been given a standardized range to categorize them into different levels of autonomy. The levels range from 0 to 5. Level 0 has no capacity of any autonomous technology; level 1 has cruise …

Laboratory Exercise – Calculating Runoff Over Land Parcels, Wade Bozeman, Steven Evans, Ryan Selee

Engineering Applications of GIS - Laboratory Exercises

When developing land, most municipalities will require that all runoff from the site be retained on site or flow into a storm water conveyance system. In the near future, new regulation will require that all runoff be retained on site. For this reason, it is important to know how much runoff can be expected to flow over a potential development site. In this lab, you will use ArcMap ModelBuilder to predict the amount of flow which can be expected over a land parcel in a storm event.

Laboratory Exercise – Frontrunner Extension, Meeya Apelu, Jordan Arrowchris, Joseph Browning

Engineering Applications of GIS - Laboratory Exercises

The Utah Transit Authority’s (UTA) FrontRunner is a commuter rail line that runs 89 miles through Weber, Davis, Salt Lake, and Utah counties. There are 16 different stops along this line which are: Pleasant View, Ogden, Roy, Clearfield, Layton, Farmington, Woods Cross, North Temple, Salt Lake Central, Murray Central, South Jordan, Draper, Lehi, American Fork, Orem and Provo (UTA 2017). Using the FrontRunner is easy and is very convenient. The popularity of this transit system is increasing and UTA has announced their future plans to continue the rail line. UTA is exploring ways to go forward with this plan and …

Relationships Between Access To Mobile Devices, Student Self-Directed Learning, And Achievement, Scott R. Bartholomew, Edward M. Reeve, Raymond Veon, Wade Goodridge, Victor R. Lee, Louis Nadelson

Applied Sciences, Technology and Education Faculty Publications

Today’s students are growing up in a world of constant connectivity, instant information, and ever-changing technological advancements. The increasingly ubiquitous nature of mobile devices among K–12 students has led many to argue for and against the inclusion of these devices in K–12 classrooms. Arguments in favor cite instant access to information and collaboration with others as positive affordances that enable student self-directed learning.

In this study, 706 middle school students from 18 technology and engineering education classes worked in groups of 2–3 to complete an open-ended engineering design challenge. Students completed design portfolios and constructed prototypes in response to the …