Engineering Commons^™

Airy Stress Function For Two Dimensional Inclusion Problems, Dharshini Rao Kavati

Mechanical and Aerospace Engineering Theses - Archive

This thesis addresses a problem of finding the elastic fields in a two-dimensional body containing an inhomogeneous inclusion using the Airy stress function which is determined so that the prescribed boundary condition at a far field and the continuity condition of the traction force and the displacement field at the interface are satisfied exactly. All the derivations and solving simultaneous equations are carried out using symbolic software.

Arc-Heated Gas Flow Experiments For Hypersonic Propulsion Applications, Christopher Matthew Roseberry

Mechanical and Aerospace Engineering Dissertations - Archive

Although hydrogen is an attractive fuel for a hypersonic air-breathing vehicle in terms of reaction rate, flame temperature, and energy content per unit mass, the substantial tank volume required to store hydrogen imposes a drag penalty to performance that tends to offset these advantages. An alternative approach is to carry a hydrocarbon fuel and convert it on-board into a hydrogen-rich gas mixture to be injected into the engine combustors. To investigate this approach, the UTA Arc-Heated Wind Tunnel facility was modified to run on methane rather than the normally used nitrogen. Previously, this facility was extensively developed for the purpose …

Reliability Of Lead-Free Solder Under Cyclic Bending, Fahad Zahedi

Mechanical and Aerospace Engineering Theses - Archive

To characterize particular compositions of lead free solder, four point cyclic bending test was conducted to study the affects of accelerated stress testing on the package to board interconnects. Nine CTBGA packages with 0.5 mm ball pitch and 12 x 12 mm package size were reflowed on 8 layered PWB's using solder balls with lead free composition alloys and different PWB copper pad finishes. The boards were subjected to test conditions based on proposed standards by JEDEC. Strain gages were mounted at different locations on the test boards as well as on bare boards in order to observe the difference …

Experimental Characterization Of Femtosecond Laser Micromachining For Silicon Mold Fabrication And Hot Embossing For Polymer Microreplication, Sunil Ranganath Belligundu

Mechanical and Aerospace Engineering Dissertations - Archive

Hot embossing is a fabrication technique employed for replicating microfeatures on a polymer surface that was primarily developed to fabricate MEMS devices for microfluidic applications. This manuscript deals with characterization of the femtosecond laser micromachining (FLM) and hot embossing (HEMM) processes for master mold fabrication on silicon and polymer replication respectively. Given the required size of the features to be fabricated or replicated, process parameters for FLM can be determined using the derived empirical equations, process parameters for the HEMM process can be established using the characteristic plots. A novel two-stage embossing process is developed and introduced that employs polymer …

Determination Of Safe Buffer Width Of Roadway To Protect Human Health Form Harmful Nox Exposure, Hetal H. Bhatt

Civil Engineering Theses - Archive

According to the 2004 EPA Trends Report, US on-road transportation sources emit 36% of nitrogen oxides (NOx), 63% of carbon monoxide (CO), and 29% of volatile organic compounds (VOCs). This research determines a safe roadway buffer width to protect human health from air pollutant (NOx) exposure. The method was used to determine a buffer width for NOx along Great Southwest Parkway in Grand Prairie, Texas. NOx health effects include eye, nose, throat, and lung irritation; cough; shortness of breath; tiredness and nausea. In the Dallas Fort Worth region, where Grand Prairie is located, on-road vehicles contribute over 50 % of …

Discharge Headway At Signalized Intersections In Monterrey, Nuevo Leon, Mexico, Luis F. Chapa

Civil Engineering Dissertations - Archive

Driver behavior has been the subject of study for almost 100 years. As a result, driver characteristics have been determined and used in the design of highway elements, both for interrupted and for free flow facilities. Signalized intersections represent the most typical interrupted flow facility, with driver reaction time and aggressiveness playing a key role in signal timing design and also in the assessing of intersection performance. These driver characteristics were first determined in the United States in the late 1940's, identifying an average headway (in seconds) between consecutive vehicles as they react to light change from red to green …

Investigation Of Breast Tumor Hemodynamics By Near Infrared Spectroscopy: Applications To Cancer Therapy Monitoring, Jae Gwan Kim

Bioengineering Dissertations - Archive

Hyperoxic gas interventions using carbogen (95% O2 and 5% CO2) or oxygen has been tried to increase the tumor oxygenation since it will enhance the therapeutic effects on the tumors. Others in the laboratory had previously applied near infrared spectroscopy (NIRS) to monitor the changes in tumor blood oxygenation during hyperoxic gas intervention and found that oxyhemoglobin concentration changes (D[HbO2]) during gas intervention can be fitted by a two-exponential equation containing two time constants. Based on the model, they formed a hypothesis that changes in oxygenated hemoglobin concentration result from well perfused and poorly perfused regions of an animal tumor …

Adaptive Sampling With Mobile Wsn, Koushil Sreenath

Electrical Engineering Theses - Archive

The spatiotemporally varying network topology of mobile sensor networks makes it very suitable for applications such as reconstruction of environmental fields through sampling at locations that maximally reduce the largest uncertainty in the field estimate. Mobile sensor networks comprise of multiple heterogeneous resources and a deadlock-free resource scheduling in the presence of shared and routing resources becomes necessary to schedule the most efficient (cost / energy / time) resource for a task. Location information is imperative in sensor networks for most applications for localized sensing where localizing the network adaptively with no additional hardware is important. Adaptive sampling approaches for …

Data-Logging & Supervisory Control In Wireless Sensor Networks, Choudhury Aditya Narayan Das

Electrical Engineering Theses - Archive

This thesis mainly emphasizes on the inclusion and implementation of the Supervisory control unit in the wireless sensor networks with a brief overlook on the cross-bow sensors and mobile sentry robots. The aim of this research has been to design an application module which would be able to manipulate the data effectively and support the Discrete Event Controller in generating the rule-based tasks by solving major issues like data-logging, alarm and event reporting and security concerns. The PC-based data logging systems provide the most flexibility, customization, and integration to the Wireless Sensor Network research project. This work has been supported …

Moving And Stationary Target Acquisition Radar Image Enhancement Through Polynomial Windows, Rajarajeswari Devarajulu

Theses and Dissertations - UTB/UTPA

The Fourier transform involved in synthetic aperture radar (SAR) imaging causes undesired sidelobes which obscure weak backscatters and affect the image clarity. These sidelobes can be suppressed without deteriorating the image resolution by smoothing functions known as windowing or apodization. Recently, the theory of orthogonal polynomials has gained considerable attention in signal processing applications. The window functions that are derived from the orthogonal polynomials have interesting sidelobe roll-off properties for better sidelobe apodization, hence it can be used for radar image enhancement. In this work, a new window is constructed from Jacobi orthogonal polynomials and its performance in SAR imaging …

Disposal Of Bridge Paint Residue, Theodore Hopwood Ii, Sudhir Palle

Kentucky Transportation Center Research Report

Paint residue generated by bridge maintenance painting commonly contains lead requiring the residue to be disposed of as a hazardous waste. Several alternatives are being investigated in this study, chemical stabilization and recycling as options for the Kentucky Transportation Cabinet (KYTC) to consider in addressing the waste stream generated by bridge maintenance painting operations.

In the initial portion of this study, four chemical stabilization materials were identified as candidates for xperimental/demonstration projects entailing maintenance painting. A recycling option was also provided. An experimental bridge painting project was let by KYTC to investigate the use of two chemical stabilizers and the …

Real-Time 3d Image Visualization System For Digital Video On A Single Chip, Nader I. Rafla

Electrical and Computer Engineering Faculty Publications and Presentations

Implementation of a real-time image visualization system on a reconfigurable chip (FPGA) is proposed. The system utilizes an innovative stereoscopic image capture, processing and visualization technique. Implementation is done as a two stage process. In the first stage, the stereo pair is captured using two image sensors. The captured images are then synchronized and sent to the second stage for fusion. A controller module is developed, designed, and placed on the FPGA for this purpose. The second stage is used for reconstruction and visualization of the 3D image. An innovative technique employing dual-processor architecture on the same single FPGA is …

Effect Of Gender On Lower Extremity Kinematics During Rapid Direction Changes: An Integrated Analysis Of Three Sports Movements, S. G. Mclean, K. B. Walker, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Anterior cruciate ligament (ACL) injury is a common sports injury, particularly in females. Gender differences in knee kinematics have been observed for specific movements, but there is limited information on how these findings relate to other joints and other movements. Here we present an integrated analysis of hip, knee and ankle kinematics across three movements linked to non-contact ACL injury. It was hypothesised that there are gender differences in lower extremity kinematics, which are consistent across sports movements. Ten female and ten male NCAA basketball players had three-dimensional hip, knee and ankle kinematics quantified during the stance phase of sidestep, …

Efficient Transcoding Of An Mpeg-2 Bit Stream To An H.264 Bit Stream, Rochelle B. Pereira

Electrical Engineering Theses - Archive

Low complexity fast transcoding of an MPEG-2 elementary stream to an H.264 elementary stream. Objective: MPEG-2 has been a widely accepted video coding standard for various applications ranging from DVD to digital TV broadcast. The new H.264 AVC standard has an even broader perspective to support high and low bit rate multimedia applications on existing and future networks. The advantage in terms of better quality at a lower bit rate is why H.264 is fast replacing MPEG-2. However, the user end hardware had previously been adapted for MPEG-2 streams. This gives rise to a need for portability between MPEG-2 and …

Analysis And Characterization Of Thermal Effects In Analog Circuits, Abhijit Avinash Chaugule

Electrical Engineering Theses - Archive

Dielectrically Isolated Bipolar Junction Transistors (DIBJTs) are used in industry for high speed and high power applications. These devices suffer from thermal heating and are subjected to change in their characteristics. This thesis explores the thermal effects involving the self heating and inter-device heating (thermal coupling) at the device as well as at the circuit level. Systematic analysis of individual device heating characteristics in a particular Current feedback operational amplifier (CFOA) design is carried out, using the VBIC (Vertical Bipolar Inter-company) model in the the Cadence SpectreS simulator. A diagnostic and design procedure is established for circuit designers to determine …

High Resolution Optical Coherence Tomography (Oct) System For Integration With A Multimodal Optical Imaging Workstation, Kapil Bharati Langer

Bioengineering Theses - Archive

Development and construction of a high resolution Optical Coherence Tomography (OCT) system is described. OCT is one of the modalities in an integrated multimode optical imaging workstation built around an inverted Differential Interference Contrast (DIC) microscope in our laboratory, to image cells and tissue samples. The design and construction of the OCT sample path is dictated by its integration to the optical imaging workstation. The OCT system is controlled via a DAC card, interfaced using LabVIEW to the computer. The image of the sample under observation is constructed from the raster scan data acquired by the DAQ. Ti-Sapphire broadband laser …

Failure Analysis Of Composite Laminates With A Hole By Using Finite Element Method, Moumita Roy

Mechanical and Aerospace Engineering Theses - Archive

Predicting the strength of a given laminate has been extensively studied. There have been several fracture models proposed but still the immense tests of composite laminates are still needed. Different material systems or lay-ups exhibit different failure modes and failure mechanisms. This thesis focuses in investigation of the failure mechanism of the [±?/02]s and [02/±?]s laminates with a hole. ANSYS finite element models with and without a crack in vicinity of hole were developed to investigate the effect of the stress distribution due to the presence of the angle ply crack. The stress concentrations were obtained. It is found that …

Structural Optimization Using Ansys And Regulated Multiquadric Response Surface Model, Ajaykumar Menon

Mechanical and Aerospace Engineering Theses - Archive

The high computational expense of large non-linear and complex finite element analysis limits or often prohibits the use of conventional codes in engineering design and multidisciplinary optimization. Consequently alternate methods such as Design of experiments (DOE) and Response surface approximation are commonly used to minimize the computational cost of running such analysis and simulation. The basic approach of such methods is to construct a simplified mathematical approximation of the computationally expensive simulation and analysis code, which is then used in place of the original code to facilitate multidisciplinary optimization, design space exploration, reliability analysis etc. When such codes along with …

Comparison Of Clinoptilolite With Gravel In A Recirculating Course Media Biofilter Treating Simulated Septic Tank Effluent, Adnan Sadikot

Civil Engineering Theses - Archive

The main objective of the pilot scale study was to compare the performance of recirulating clinoptilolite biofilter with course gravel biofilter used to treat simulated septic tank effluent by simultaneous nitrification and denitrification. For better comparison of performance of total inorganic nitrogen removal and COD removal both the biofilter were chosen of identical size and identical operating conditions were maintained in the laboratory setup. Both the biofilters were operated at recycle ratio of 6 and surface hydraulic loading rate of 7.5 gal/ft2/day without recycle and 52.5 gal/ft2/day with recycle through out the duration of the duration of the research. Results …

Effects Of Water-Cement Ratio On Deep Mixing Treated Expansive Clay Characteristics, Siva Prasad Pathivada

Civil Engineering Theses - Archive

The structures built on the unstabilized expansive soils are subjected to distress due to swell shrink behavior due to seasonal fluctuations. Medium stiff expansive clays with moderate and high PI were collected from two sites located at IH 820 N bound in Fort Worth, Texas. Deep soil mixing technique was proposed as a potential solution to counter the shrink swell movements of the expansive soil. These soils were stabilized using lime and cement as a whole and in combinations at different proportions in laboratory conditions simulating field deep soil mixing. Similar studies performed on soft soils revealed several factors mainly …

Numerical Modeling And Analysis Of Pile Supported Embankments, Krishna Nag Rao

Civil Engineering Theses - Archive

Very soft clays are often avoided in construction due to their low shear strength and high compressibility. Special construction methods are adopted when embankments are constructed on very soft clay or peat. Design of structures on soft ground, where the structure impose large loads onto the ground raises several concerns on factors like bearing capacity failure, differential settlements, lateral pressures and structural instability. Shallow and deep stabilization of soft ground are most frequently used special construction techniques adopted in geotechnical engineering. Chemical (lime and cement) stabilization has been extensively used in both shallow and deep stabilization in order to improve …

Guidelines To Select A Computerized Maintenance Management System, Dattaraj Kamalapurkar

Masters Theses

In today's highly competitive global economy, maintenance personnel are presented with more difficult challenges than at any previous point in time. In order to meet these challenges, many maintenance managers tend to rely . on Computerized Maintenance Management System (CMMS). When properly selected and implemented, CMMS is one of the most powerful cost reduction tools in any organization. However in reality, many CMMS implementations fail rather than achieve success. While there are many contributing factors, one major factor that greatly impacts successful implementation is selecting the right CMMS system. With more than 200 CMMS systems to choose from, selecting the …

An Automated Optimal Design Of A Fan Blade Using An Integrated Cfd/Mdo Computer Environment, Uyi O. Idahosa

Master's Theses - Daytona Beach

The objective of the investigation is the development of more efficient design methodologies based on the applications of established design tools including Computational Fluid Dynamics (CFD) and non-linear Multidisciplinary Design Optimization (MDO) algorithms. Well known evolutionary type optimization algorithms include the Particle Swarm Optimization (PSO), Response Surface Optimization (RSO) and Genetic (GA) Algorithms. The benchmark case study is the optimal design of a low speed fan for an industrial air-conditioning application using the Response Surface Optimization (RSO) algorithm.

The optimization algorithm controls the variations of parameters that describe the three-dimensional geometry of the blade while applying performance and geometrical constraints …

Human Performance Multimeter: Investigation Of The Fourth Generation Prototype, Rahul Mulukutla

Electrical Engineering Theses - Archive

The focus of this thesis is the development and investigation related to the newest prototype version of the Human Performance MultiMeter (HPMM). Version 4 is a technologically advanced, compact, portable and self-contained unit that is the result of an on-going effort in human performance measurement covering a 25 year history at the Human Performance Institute involving the conception, development, and evaluation of over four hundred different measures. Such measurements are applicable in areas ranging from medical diagnosis and rehabilitation to ergonomics and athletic proficiency. The work included verification of the functionality of a new hardware platform, modification of previously developed …

Wavelet Domain Diversity Method For Transmission Of Images Over Wireless Sytems Using Hybrid (Ofdm-Cdma-Sfh) Concept And Its Real Time Implementation In Tms320c6713 Dsp Development Board, Madhu Rangappagowda

Electrical Engineering Theses - Archive

In this thesis a new OFDM based wavelet domain diversity combining method is proposed to combat errors during image transmission on wireless channels. A novel concept of utilizing OFDM sub-carriers to attain diversity is designed and analyzed. For images represented in the wavelet domain, diversity is used to obtain multiple data streams using OFDM symbols corresponding to the transmitted image at the receiver. These individual image data streams are combined to form a composite image with higher perceptual quality. Both uncompressed and compressed images are considered. The SPIHT algorithm is used for image compression. Diversity combining methods for both uncompressed …

Cmos Optical Transimpedance Amplifier Design For Pam Signaling Application, Hemalatha Shanmugasundaram

Electrical Engineering Theses - Archive

The advent of Internet telephony and the surge in data communication field necessitate the use of broadband communication systems. The Optical communication systems has been suggested as an attractive solution to cope with the high speed data rate and large throughput bottleneck of the long haul communication systems due to their cheaper deployment cost. In the world of miniaturization, CMOS circuits have been widely used to develop the opto-electronic components. However, the intricacy involved in the design of high speed optical front-end is higher due to the poor noise performance of CMOS circuits compared to their bipolar counter parts. Despite …

Laboratory And Field Investigations To Address Erosion, Volume Change And Desiccation Cracking Of Compost Amended Expansive Subsoils, Napat Intharasombat

Civil Engineering Dissertations - Archive

Desiccations cracks are formed during drying process of fine grained cohesive soils in summer and these cracks often appear on unpaved subgrades due to direct exposure to sun. These cracks allow surface runoff infiltration into subsoils and eventually weaken adjacent base and subgrade layers. The loss of support from these underlying layers results in both longitudinal and transverse cracks in paved shoulders and pavements. Composting is a successful method of recycling organic waste material into stabilized materials that could be used for erosion control and landscaping applications. Since compost is rich in fibrous material and exhibits moisture affinity characteristics, it …

Evaluation Of Mechanical Properties Of Recycled Aggregate Concrete, Sajjad Ali Khan

Masters Theses

The maintenance and repair work in the civil engineering infrastructures develops the production of huge wastes which causes the growth of waste piles, additional costs in construction projects and some environmental problems. If this waste is recycled and used again in construction projects, it will help to overcome the problems discussed earlier. Moreover, if natural aggregates are supplemented by recycled aggregate, it will preserve the natural resources and also put a pause in the deterioration of natural landscape.

This thesis addresses the importance of using recycled aggregate in concrete structures. Its practical feasibility in construction projects is studied in light …

How Does The Sound Pressure Generated By Circumaural, Supra-Aural, And Insert Earphones Differ For Adult And Infant Ears?, Susan E. Voss, Barbara S. Herrmann

Engineering: Faculty Publications

Objective:

To determine how the ear canal sound pressure levels generated by circumaural, supra-aural, and insert earphones differ when coupled to the normal adult and infant ear.

Design:

The ratio between the sound pressure generated in an adult ear and an infant ear was calculated for three types of earphones: a circumaural earphone (Natus Medical, ALGO with Flexicoupler™), a supra-aural earphone (Telephonics, TDH-49 with MXAR cushion), and an insert earphone placed in the ear canal (Etymo↕tic Research, ER-3A). The calculations are based on (1) previously published measurements of ear canal impedances in adult and infant (ages 1, 3, 6, 12, …

Reliability Measurement Of Mass Storage System For Onboard Instrumentation, Minsu Choi, Nohpill Park, Vincenzo Piuri, Fabrizio Lombardi

Electrical and Computer Engineering Faculty Research & Creative Works

Advances in spaceborne vehicular technology have made possible the long-life duration of the mission in harsh cosmic environments. Reliability and data integrity are the commonly emphasized requirements of spaceborne solid-state mass storage systems, because faults due to the harsh cosmic environments, such as extreme radiation, can be experienced throughout the mission. Acceptable dependability for these instruments has been achieved by using redundancy and repair. Reconfiguration (repair) of memory arrays using spare memory lines is the most common technique for reliability enhancement of memories with faults. Faulty cells in memory arrays are known to show spatial locality. This physical phenomenon is …