Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 30 of 84
Full-Text Articles in Entire DC Network
Removal Of Carbonyl Sulfide Using Compost Biofilter: Measurement Of Removal Rates And Elimination Capacity In Conjunction With Hydrogen Sulfide, Divya R. Garrepalli
Removal Of Carbonyl Sulfide Using Compost Biofilter: Measurement Of Removal Rates And Elimination Capacity In Conjunction With Hydrogen Sulfide, Divya R. Garrepalli
Civil Engineering Theses
A lab study using biofiltration was conducted using three PVC columns as biofilters, with hardwood chips and compost as the media. Previous research determined the removal efficiency of carbonyl sulfide alone. (Nawal, 2004) Typically, however H2S is present with COS in the air streams from wastewater treatment plant units. In the current study, different combinations of hydrogen sulfide and carbonyl sulfide gases were tested using H2S/COS ratios typical of the concentrations from wastewater treatment plants. Various runs were conducted using compost and hardwood chips individually and also with an 80:20 ratio by volume of wood chips to compost. The specific …
Laboratory And Field Investigations To Address Erosion, Volume Change And Desiccation Cracking Of Compost Amended Expansive Subsoils, Napat Intharasombat
Laboratory And Field Investigations To Address Erosion, Volume Change And Desiccation Cracking Of Compost Amended Expansive Subsoils, Napat Intharasombat
Civil Engineering Dissertations
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 …
Discharge Headway At Signalized Intersections In Monterrey, Nuevo Leon, Mexico, Luis F. Chapa
Discharge Headway At Signalized Intersections In Monterrey, Nuevo Leon, Mexico, Luis F. Chapa
Civil Engineering Dissertations
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 …
Parametric And Non-Parametric Analysis Of Carotid Sinus Baroreflex System Using Electrically Induced Muscle Contraction, Sheetal D. Deshmukh
Parametric And Non-Parametric Analysis Of Carotid Sinus Baroreflex System Using Electrically Induced Muscle Contraction, Sheetal D. Deshmukh
Bioengineering Theses
The arterial pressure is an important physiological parameter which if not maintained at desired level may lead to fatal disorders or in worst situations even death. The physiological feedback control mechanism in order to regulate the arterial pressure is performed by the baroreceptors. In this study the dynamic characteristics of carotid sinus baroreceptor are identified to obtain the open-loop characteristics of the carotid sinus pressure (CSP, mmHg) to the renal sympathetic nerve activity (RSNA, Arbitrary unit), RSNA to systemic arterial pressure (SAP, mmHg), CSP to SAP and CSP to heart rate (HR, bpm).The purpose of this study was to know …
Comparison Of Clinoptilolite With Gravel In A Recirculating Course Media Biofilter Treating Simulated Septic Tank Effluent, Adnan Sadikot
Comparison Of Clinoptilolite With Gravel In A Recirculating Course Media Biofilter Treating Simulated Septic Tank Effluent, Adnan Sadikot
Civil Engineering Theses
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 …
Investigation Of Breast Tumor Hemodynamics By Near Infrared Spectroscopy: Applications To Cancer Therapy Monitoring, Jae Gwan Kim
Investigation Of Breast Tumor Hemodynamics By Near Infrared Spectroscopy: Applications To Cancer Therapy Monitoring, Jae Gwan Kim
Bioengineering Dissertations
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 …
Fabrication And Mechanical Characterization Of A Two-Ply Cross Fiber Stent And Fibers Comprising Blends Of Poly(L-Lactic Acid), Sushma Gampa
Fabrication And Mechanical Characterization Of A Two-Ply Cross Fiber Stent And Fibers Comprising Blends Of Poly(L-Lactic Acid), Sushma Gampa
Bioengineering Theses
Recent studies indicate that stabilization of vulnerable atherosclerotic plaques is critical for minimizing acute coronary syndromes. In this regard a new biodegradable stent design, the Two-ply cross fiber stent, has been developed to reduce stent-imposed stresses on such plaque and to provide increased drug reservoir capability. A comparative study of the mechanical properties of Two-ply and Single-ply stent designs was performed. Fibers comprising PLLA blends were developed and their thermal and mechanical properties were determined. Lateral spreading of helical fibers upon deployment of the Two ply design was observed that, in theory, may reduce stresses on the plaque surface. The …
High Resolution Optical Coherence Tomography (Oct) System For Integration With A Multimodal Optical Imaging Workstation, Kapil Bharati Langer
High Resolution Optical Coherence Tomography (Oct) System For Integration With A Multimodal Optical Imaging Workstation, Kapil Bharati Langer
Bioengineering Theses
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 …
Determination Of Safe Buffer Width Of Roadway To Protect Human Health Form Harmful Nox Exposure, Hetal H. Bhatt
Determination Of Safe Buffer Width Of Roadway To Protect Human Health Form Harmful Nox Exposure, Hetal H. Bhatt
Civil Engineering Theses
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 …
Numerical Modeling And Analysis Of Pile Supported Embankments, Krishna Nag Rao
Numerical Modeling And Analysis Of Pile Supported Embankments, Krishna Nag Rao
Civil Engineering Theses
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 …
Effects Of Water-Cement Ratio On Deep Mixing Treated Expansive Clay Characteristics, Siva Prasad Pathivada
Effects Of Water-Cement Ratio On Deep Mixing Treated Expansive Clay Characteristics, Siva Prasad Pathivada
Civil Engineering Theses
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 …
Airy Stress Function For Two Dimensional Inclusion Problems, Dharshini Rao Kavati
Airy Stress Function For Two Dimensional Inclusion Problems, Dharshini Rao Kavati
Mechanical and Aerospace Engineering Theses
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.
Structural Optimization Using Ansys And Regulated Multiquadric Response Surface Model, Ajaykumar Menon
Structural Optimization Using Ansys And Regulated Multiquadric Response Surface Model, Ajaykumar Menon
Mechanical and Aerospace Engineering Theses
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 …
Failure Analysis Of Composite Laminates With A Hole By Using Finite Element Method, Moumita Roy
Failure Analysis Of Composite Laminates With A Hole By Using Finite Element Method, Moumita Roy
Mechanical and Aerospace Engineering Theses
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 …
Modular Multi-Scale Assembly System For Mems Packaging, Rakesh Murthy
Modular Multi-Scale Assembly System For Mems Packaging, Rakesh Murthy
Mechanical and Aerospace Engineering Theses
A multi-scale robotic assembly problem is approached here with focus on mechanical design for precision positioning at the microscale. The assembly system is characterized in terms of accuracy/repeatability and calibration via experiments. The MEMS packaging requirements are studied from an assembly point of view. The tolerance budget of the assembly ranges from 4 microns to 300 microns. The system components include robots, microstages, end-effectors and fixtures that accomplish the assembly tasks. Task assignment amongst this hardware has been accomplished based on precision and dexterity availability. Various end-effectors and fixtures have been designed for use with off-the-shelf hardware (robots and microstages) …
Parametric Cycle Analysis For Pulse Detonation Engines, Haider Hekiri
Parametric Cycle Analysis For Pulse Detonation Engines, Haider Hekiri
Mechanical and Aerospace Engineering Theses
The performance of an ejector-driven pulse detonation engine (PDE) with an afterburner is analytically estimated. In the analysis, the PDE was modeled as a straight tube, closed at the front end and open at the other. A detonation wave starts to travel after it is ignited at the closed end, causing a Chapman-Jouguet detonation wave followed by a Taylor rarefaction to travel to the open end. At that point, rarefaction waves are reflected back to the closed end. The result is a high thrust due to both the primary and secondary flows of the ejector-driven PDE. A theoretical analysis is …
Design And Analysis Of Multi-Functional Laparoscopic Tool, Vadakkapattu Candadai Venkat Raghavan
Design And Analysis Of Multi-Functional Laparoscopic Tool, Vadakkapattu Candadai Venkat Raghavan
Mechanical and Aerospace Engineering Theses
Laparoscopic tools have been developed over many years, but there is a need for a laparoscopic tool that can be used for multiple purposes without the need to be removed and reinserted in the body. This thesis discusses the design of such a multi-functional laparoscopic tool with the ability to independently actuate grasping and shearing mechanisms, and is modular enough to be easily adapted to robot assisted surgical techniques. The envisioned tool can be divided into three main sections - the surgeon interface, the transmission mechanism, and the end effector. The surgeon interface mainly consists of a handle and two …
Reliability Of Lead-Free Solder Under Cyclic Bending, Fahad Zahedi
Reliability Of Lead-Free Solder Under Cyclic Bending, Fahad Zahedi
Mechanical and Aerospace Engineering Theses
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 …
Interactions Between Antiwear Agent And Novel Additive In Engine Oils, Kajal Parekh
Interactions Between Antiwear Agent And Novel Additive In Engine Oils, Kajal Parekh
Material Science and Engineering Theses
Research has shown that side/end products of phosphorus and sulfur compounds in engine oils reduce effective life of exhaust catalysts of automobiles resulting in harmful emissions. Thus environmental regulations have been imposed on phosphorus levels in engine oils. The main source of phosphorus in today's oils is the indispensable antiwear agent Zinc Dialkyl Dithiophosphate (ZDDP). To find cost-effective non-phosphorus substitute has not proven fruitful. A unique way of reducing phosphorus or ZDDP level while maintaining good antiwear performance has been achieved by introduction of a novel additive FeF3 along with ZDDP. It appears that the interactions between FeF3 and ZDDP …
Efficient Transcoding Of An Mpeg-2 Bit Stream To An H.264 Bit Stream, Rochelle B. Pereira
Efficient Transcoding Of An Mpeg-2 Bit Stream To An H.264 Bit Stream, Rochelle B. Pereira
Electrical Engineering Theses
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 …
Arc-Heated Gas Flow Experiments For Hypersonic Propulsion Applications, Christopher Matthew Roseberry
Arc-Heated Gas Flow Experiments For Hypersonic Propulsion Applications, Christopher Matthew Roseberry
Mechanical and Aerospace Engineering Dissertations
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 …
Analysis And Characterization Of Thermal Effects In Analog Circuits, Abhijit Avinash Chaugule
Analysis And Characterization Of Thermal Effects In Analog Circuits, Abhijit Avinash Chaugule
Electrical Engineering Theses
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 …
Adaptive Sampling With Mobile Wsn, Koushil Sreenath
Adaptive Sampling With Mobile Wsn, Koushil Sreenath
Electrical Engineering Theses
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
Data-Logging & Supervisory Control In Wireless Sensor Networks, Choudhury Aditya Narayan Das
Electrical Engineering Theses
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 …
Numerical Study Of Chemically Reacting Viscous Flow Relevant To Pulsed Detonation Engines, Tae-Hyeong Yi
Numerical Study Of Chemically Reacting Viscous Flow Relevant To Pulsed Detonation Engines, Tae-Hyeong Yi
Mechanical and Aerospace Engineering Dissertations
A computational fluid dynamics code for two-dimensional, multi-species, laminar Navier-Stokes equations is developed to simulate a recently proposed engine concept for a pulsed detonation based propulsion system and to investigate the feasibility of the engine of the concept.The governing equations that include transport phenomena such as viscosity, thermal conduction and diffusion are coupled with chemical reactions. The gas is assumed to be thermally perfect and in chemically non-equilibrium. The stiffness due to coupling the fluid dynamics and the chemical kinetics is properly taken care of by using a time-operator splitting method and a variable coefficient ordinary differential equation solver. A …
Cmos Optical Transimpedance Amplifier Design For Pam Signaling Application, Hemalatha Shanmugasundaram
Cmos Optical Transimpedance Amplifier Design For Pam Signaling Application, Hemalatha Shanmugasundaram
Electrical Engineering Theses
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 …
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
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
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 …
Statistics-Based Approaches To Stochastic Optimal Control Problems, Aihong Wen
Statistics-Based Approaches To Stochastic Optimal Control Problems, Aihong Wen
Industrial, Manufacturing, and Systems Engineering Dissertations
This dissertation develops practical approaches to stochastic optimal control problems in the absence of linear system transition functions, quadratic cost functions, and/or Gaussian random disturbances. In such type of problems, an analytical solution is impossible and numerical synthesis techniques have to be applied. The ''classic'' algorithms existing in the literature suffer from the problem of the''curse of dimensionality,'' an exponential increase of computation time and memory requirements as the dimension of the problem grows. The statistics-based numerical approaches are presented as the main tools for mitigating the ``curse of dimensionality'' phenomenon. Two approaches are explored: (A) stochastic dynamic programming (SDP), …
Experimental Characterization Of Femtosecond Laser Micromachining For Silicon Mold Fabrication And Hot Embossing For Polymer Microreplication, Sunil Ranganath Belligundu
Experimental Characterization Of Femtosecond Laser Micromachining For Silicon Mold Fabrication And Hot Embossing For Polymer Microreplication, Sunil Ranganath Belligundu
Mechanical and Aerospace Engineering Dissertations
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 …
Human Performance Multimeter: Investigation Of The Fourth Generation Prototype, Rahul Mulukutla
Human Performance Multimeter: Investigation Of The Fourth Generation Prototype, Rahul Mulukutla
Electrical Engineering Theses
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 …