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Full-Text Articles in Engineering
Synthesis And Evaluation Of Bioceramics For Orthopedics And Tissue Culture Applications, Hande Demirkiran
Synthesis And Evaluation Of Bioceramics For Orthopedics And Tissue Culture Applications, Hande Demirkiran
Material Science and Engineering Dissertations
Hydroxyapatite is the most well known phosphate in the biologically active phosphate ceramic family by virtue of its similarity to natural bone mineral. Among all bioglass compositions Bioglass®45S5 is one of the most bioactive glasses. This study initially started by adding different amounts (1, 2.5, 5, 10, and 25 wt. %) of Bioglass®45S5 to synthetic hydroxyapatite in order to improve the bioactivity of these bioceramics.The chemistries formed by sintering and their effect on different material properties including bioactivity were identified by using various techniques, such as powder and thin film x-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray …
Self Powered Sensing By Combining Novel Sensor Architectures With Energy Harvesting, Vishwas Bedekar
Self Powered Sensing By Combining Novel Sensor Architectures With Energy Harvesting, Vishwas Bedekar
Material Science and Engineering Dissertations
Recent advancements in the field of wireless sensor networks have resulted in increasing demand for self-powering techniques that reduces the dependence on batteries. In order to address this problem, there has been significant effort on generating small electrical power locally by harvesting energy from freely available environmental sources such as mechanical vibrations, wind, and stray magnetic field. Further, there is need for inventing new sensing techniques to reduce the overall power consumption. The road for reaching the destination of self-powered sensor networks requires cooperative progress in reduction in sensor power consumption by developing new sensing mechanisms and local generation of …
Synthesis, Characterization And Potential Applications Of Fept Nanoparticles, Vikas Nandwana
Synthesis, Characterization And Potential Applications Of Fept Nanoparticles, Vikas Nandwana
Material Science and Engineering Dissertations
Monodisperse FePt nanoparticles with controlled size and geometry have drawn great attention in the last decade for fundamental scientific studies and for their potential applications in advanced materials and devices such as ultra-high-density magnetic recording media, exchange-coupled nanocomposite magnets, biomedicines and nanodevices. This dissertation focuses on the synthesis and characterization of FePt nanoparticles and their use in potential applications. The FePt nanoparticles of different size (2 to 16 nm) and shape (spherical, cubic, rod) were synthesized by a chemical solution method. The size and shape of these particles were controlled by adjusting reaction parameters. The as-synthesized FePt nanoparticles have chemically …
Tribological Performance Of Ashless Antiwear Additives Under Extreme Pressure Conditions, Bohoon Kim
Tribological Performance Of Ashless Antiwear Additives Under Extreme Pressure Conditions, Bohoon Kim
Material Science and Engineering Dissertations
Zinc diakyl dithiophosphate (ZDDP) has been used in engine oil for several decades as an antiwear additive. However, ZDDP is the primary source of P, S and Zn in the exhaust, which results in frequent maintenance or replacement of exhaust gas treatment systems. The use of ashless additives is more desirable because of recent environmental regulations. The main goal of this research was to develop a fundamental understanding of how ashless compounds protect the tribological surface in comparison to ZDDP. X-ray absorption near edge structure spectroscopy (XANES) has been performed on tribo and thermal films in order to investigate the …
Magnetically Anchored "Reduced Trocar" Laparoscopy: Evolution Of Surgical Robotics, Richard Bergs
Magnetically Anchored "Reduced Trocar" Laparoscopy: Evolution Of Surgical Robotics, Richard Bergs
Bioengineering Theses
Laparoscopic surgery has become increasingly popular over the last few years due to its benefits; lower morbidity, less perceived pain, better cosmesis results, and less hospital time. For the surgeon however, there are fundamental issues that can make a laparoscopic procedure more difficult than simple open surgery; loss of tactile feel, limited working envelope, high demand for hand-eye coordination, and one trocar-port required for each tool. A revolutionary concept of using magnetics to support tooling across the abdominal wall was conceived by Dr. Jeffrey Cadeddu and his colleagues at the University of Texas Southwestern Medical Center. Collectively referred to as …
Non-Linear Finite Element Dynamic Analysis Of The Effect Of Compaction On Underground Conduits, Anupong Kararam
Non-Linear Finite Element Dynamic Analysis Of The Effect Of Compaction On Underground Conduits, Anupong Kararam
Civil Engineering Dissertations
Construction loads are an important but often overlooked factor in underground pipe design and installation. Common compaction equipments used in pipeline construction can be a major contributor to pipe damage. To reduce load concentrations in excess of the design loads, construction equipment should be kept at a safe distance above the pipe location.This study investigates the behavior of a reinforced concrete pipeline system under a compaction process. The full-scale experimental test was conducted using a Type-2 standard trench installations soil and minimum compaction requirement. Using a compaction machine "hoe pack" and including the weight of a backhoe, a maximum dynamic …
Development And Benefits Of A Leed Project Management Database, Teri Schmig
Development And Benefits Of A Leed Project Management Database, Teri Schmig
Civil Engineering Theses
The U.S. Green Building Council is a non-profit community of industry leaders working to make green buildings available to everyone. The documentation process for achieving Leadership in Energy and Environmental Design (LEED® ) certification is highly complex and more time-consuming than necessary with currently employed systems. This thesis explains the need for development of a relational database as a means to increase the efficiency of the documentation process to meet LEED® requirements. This database will provide the construction project team a relational platform that guides the user through the LEED® administration and certification process. By developing a LEED® specific project …
Nonlinear Dynamic Analysis Of Hybrid Frames, Dobrinka Radulova
Nonlinear Dynamic Analysis Of Hybrid Frames, Dobrinka Radulova
Civil Engineering Theses
This study proposes a hybrid frame system consisting of rigid and semi-rigid connections subjected to a dynamic loading. Two building geometries are chosen to represent low-rise and high-rise buildings. Multiple locations for placement of semi-rigid connections are proposed, and the hybrid systems with the most efficient energy dissipation are identified. During this analysis, five earthquake records are used to provide a spectrum of frequencies. Five practical semi-rigid connection types and one connection with analytical parameters are also modeled into the selected hybrid combinations by applying zero-length springs at the ends of beams, in which their nonlinear constitutive relation is defined …
Long Term Durability Studies On Chemically Treated Reclaimed Asphalt Pavement (Rap) Materials, Vijay Krishna Ganne
Long Term Durability Studies On Chemically Treated Reclaimed Asphalt Pavement (Rap) Materials, Vijay Krishna Ganne
Civil Engineering Theses
Reclaimed Asphalt Pavement (RAP) is a well known construction material which has been used in Hot Mix Asphalt (HMA) to reduce material costs and stabilizing the pavements for several years. It has been reported that out of 45 million tons of RAP produced every year in US, only 33% is being used in HMA. It is clear that a large amount of RAP produced is disposed off as a waste material in landfills. Hence, in order to utilize the maximum percentage of RAP and reduce the disposal rate, stabilized RAP can be effectively used as a base layer instead of …
Use Of Electrical Resistivity And Multichannel Analysis Of Surface Wave Geophysical Tomography In Geotechnical Site Characterization Of Dam, Joshua Lee Hubbard
Use Of Electrical Resistivity And Multichannel Analysis Of Surface Wave Geophysical Tomography In Geotechnical Site Characterization Of Dam, Joshua Lee Hubbard
Civil Engineering Theses
Performance of geotechnical site characterization is a primary function of geotechnical engineers. Generalizations required to extrapolate conventional geotechnical boring data can limit the effectiveness of site assessments. Advancements in geophysical technology have simplified means of data acquisition and interpretation of electrical and seismic testing, allowing a broader audience of practitioners to utilize methods for various engineering and environmental applications. In this study, electrical resistivity and multichannel analysis of surface waves (MASW) seismic geophysical methods are used to expound upon previous geotechnical sampling and in situ testing conducted at an earthen dam site in East Texas. Findings from this study show: …
In Situ Crosslinkable Polyesters For Tissue Engineering And Drug Delivery, Dipendra Raj Gyawali
In Situ Crosslinkable Polyesters For Tissue Engineering And Drug Delivery, Dipendra Raj Gyawali
Bioengineering Theses
In situ crosslinkable elastic materials are increasingly being explored for various biomedical applications such as drug delivery and tissue engineering due to their site specific nature. The creation of an in situ crosslinkable elastomer rich in pendant chemistry has been a challenge in the field of biomaterials. Herein, we have developed two new in situ biodegradable materials: poly(octamethylene maleate citrates) (POMC) and poly(poly(ethylene glycol) maleate citrate) (PPEGMC). These materials are all low molecular weight in their pre-polymeric form, which shows their potential to be used as an injectable biomaterial. The preservation of pendant carboxylic and hydroxyl groups in these polymeric …
Biaxial Investigation Of Periosteal Mechanics, Olumide O. Aruwajoye
Biaxial Investigation Of Periosteal Mechanics, Olumide O. Aruwajoye
Bioengineering Theses
Limb lengthening procedures are used commonly to correct limb length discrepancies. Current methods in limb lengthening require a distraction of 1 mm per day using an external fixation device. Although the underlying mechanisms of new bone growth have been studied and discussed extensively, they remain not fully understood. It is thought, however, that mechanoreceptor cells of the periosteum play an important role. In an attempt to understand the contribution of periosteum, the biaxial mechanical properties of the periosteum are studied. Freshly excised porcine periosteum was used to investigate the effects of preload on the material symmetry, and the effects of …
Development Of Brownfield Database Using Gis, Jubair Hossain
Development Of Brownfield Database Using Gis, Jubair Hossain
Civil Engineering Theses
Brownfields are abandoned, idled or underutilized industrial or commercial sites where expansion or redevelopment is complicated by actual or perceived environmental contamination. Brownfields may be as small as a vacant city lot or as large as an abandoned manufacturing facility occupying several hundred acres. The extent of contamination encountered at brownfield sites may range from minor surface debris to extensive, dangerous soil and ground-water contamination. Concerning the communities in which brownfields are located, redevelopment may improve community appearance and image, relieve associated health and environmental concerns and produce a beneficial economic effect through increased property values and employment opportunities.The overall …
Analysis Of Oxygen Uptake During Blood Flow Through A Rectangular Microchannel: A Two Phase Eulerian Model With Oxygen-Hemoglobin Reaction, Jamie Wright
Bioengineering Theses
The evolution of oxygenator design has culminated in the current strategy of utilizing micro-porous membranes to separate blood and oxygen phases while utilizing extra-luminal blood flow orientations to promote passive and active secondary mixing of the blood to inhibit the build up of concentration boundary layers near oxygen transfer surfaces that impede efficiency. Advances in fabrication techniques could allow for the manufacturing of oxygenators employing microchannels to decrease the diffusion path between oxygen and the red blood cells, more closely mimicking the strategy employed by the body. Because blood is actually a complex suspension, it is difficult to model. Furthermore, …
Theoretical Feasibility Study For A Conceptual Approach To Trenchless Replacement Of Culverts, Diego R. Calderon
Theoretical Feasibility Study For A Conceptual Approach To Trenchless Replacement Of Culverts, Diego R. Calderon
Civil Engineering Theses
Culvert damage and collapses and their renewal alternatives are a raising concern in today's infrastructure topics. In most cases damages are irreversible; however, in many cases opportunities exist to correct and renew. While conventional open-cut construction brings inconvenience to the public, trenchless technology brings a greener, reliable and more socially acceptable alternative to renew culverts. Considering the strong dependency on highway transportation by the American lifestyle, collapses of culverts in major roads may produce chaotic traffic redirections. To reduce this risk, this research sets a path for a construction and feasibility study on a new culvert replacement method based on …
Advances In Helical Stent Design And Fabrication: Studies Of Stent Thermal Treatment, Stent Mechanical Properties, And Stent Interactions With A Simulated Plaque-Laden Artery, Tre Raymond Welch
Bioengineering Dissertations
Advancements in processing biomaterials have lead to the development of bioresorbable PLLA drug-loaded stents with different geometric configurations. To further advance the technology, systematic studies have been carried out. This dissertation consists of six specific aims: 1) To characterize the effects of thermal annealing on the mechanical characteristics of PLLA helical stent, 2) To characterize the mechanical characteristics of a PLLA double helix stent, 3) To characterize the physical and chemical properties of PLLA films impregnated with niacin and curcumin, 4) To characterize the mechanical interaction of expanded stent and vascular wall with both model simulation and experimental studies using …
Development Of An Optical Spectroscopic Method To Detect Neurohemodynamic Changes Induced By Pain In Rats, Sweta Narvenkar
Development Of An Optical Spectroscopic Method To Detect Neurohemodynamic Changes Induced By Pain In Rats, Sweta Narvenkar
Bioengineering Theses
In my optical spectroscopy study, multi-channel, thin optical probes with short source-detector separation have been implemented, calibrated, and used along with a multi-channel spectrometer as a quantitative technique to observe changes in vascular hemoglobin concentration and hemoglobin oxygen saturation as well as light scattering of tissues. Each of the four needle probes used in my study consists of two bifurcated fibers; one fiber is connected to a halogen light source and the other fiber to a CCD-array spectrometer having a spectral window from 450 nm to 900 nm. Each fiber is 100 micron in diameter. As we utilized the four …
A Comprehensive Study Of Recycled Concrete Aggregates As A Drainable Base Layer For Pavements, Juan Bosquez
A Comprehensive Study Of Recycled Concrete Aggregates As A Drainable Base Layer For Pavements, Juan Bosquez
Civil Engineering Dissertations
The use of recycled materials in construction is becoming increasingly popular due to the shortage of raw materials. Coupled with the environmental concerns surrounding the quarrying of natural minerals, waste materials are being considered as viable replacement sources. By recycling waste materials, available landfill space is increased and costs of transportation are reduced. This dissertation study was conducted to evaluate the use of recycled concrete aggregates as flexible base as per the requirements of the Texas Department of Transportation (2004). Two sources of recycled aggregates and one source of natural limestone aggregate were collected from the Dallas/Fort Worth Area and …
Managed Lanes Weaving And Access Guideliness, Chulsu Yang
Managed Lanes Weaving And Access Guideliness, Chulsu Yang
Civil Engineering Dissertations
To maximize the potential for successful managed lanes (MLs) operations, there are critical design issues that require special attention. Adequate ML access spacing and length of the ML access opening are required for the preservation of freeway capacity, level of service, and safety. The traffic weaving from an entrance ramp to the general purpose lanes across to a ML access point and vice versa are effectively modeled as a two-sided Type C weave. The 2000 Highway Capacity Manual (HCM) methodology was calibrated for the major weave without lane balance or merging (standard Type C weave) but not for the two-sided …
An Evaluation Of The Biomechanical Properties Of The Superficial Musculoaponeurotic System, Matthew David Ruff
An Evaluation Of The Biomechanical Properties Of The Superficial Musculoaponeurotic System, Matthew David Ruff
Bioengineering Theses
The Superficial Musculoaponeurotic System (SMAS) is a well defined tissue layer of the face commonly utilized in facial surgery, including facelifts. There are several reasons for the utilization of this tissue, including aesthetic results and reliability. Basic to the outcomes for these procedures are the inherent biomechanical properties of the SMAS. Most important for the surgeon in this regard are tissue burst pressure, elasticity, stress-relaxation under load, and creep. This study experimentally determines the biomechanical properties for human cadaveric tissue specimens. As well as defining the cited biomechanical properties, the study examines how they change, as sampled from different regions …
Performance Of Large Scale Steel Fiber Reinforced Concrete Deep Beam With Single Opening Under Monotonic Loading, Carlos Flores
Performance Of Large Scale Steel Fiber Reinforced Concrete Deep Beam With Single Opening Under Monotonic Loading, Carlos Flores
Civil Engineering Theses
The design of complex, discontinuous stress trajectory regions (D-regions) is complex in natureand cumbersome to design. The performance of a large scale steel fiber reinforced concrete (SFRC)deep beam with single opening under monotonic loading was tested under controlled conditions. Themain objective of this study was to see if Steel Fiber Reinforced Concrete (SFRC), used as a bettermaterial than reinforced concrete (RC) offered an alternate to the cumbersome and iterative stepsinvolved in strut-and-tie (STM) methodology. Additionally, a similar reinforced concrete (RC) specimenwas tested under the same controlled condition designed with classical strut-and-tie model designmethodology reinforced using conventional steel bars.Material testing was …
Applications Of Gis For Mapping And Tracking Underground Infrastructure, Anurag Babu Bhogenahally Lakshminarayanappa
Applications Of Gis For Mapping And Tracking Underground Infrastructure, Anurag Babu Bhogenahally Lakshminarayanappa
Civil Engineering Theses
The main objective of this research is to apply Geographic Information Systems (GIS) for construction and renewal of underground infrastructures. As a first step, a suitability analysis to determine location of existing underground infrastructure is performed. Next, a GIS template is developed using a digital elevation model (DEM) to get a three dimensional visualization of the underground infrastructure. Creating a Google Map using ArcGIS is one of the key features of this research, which provides an exact location of the existing site and distances from the nearby reference points. Once the GIS data is exported to Google Map and Google …
Controlled Vascular Cellular Growth By Microstructured Patterned Surfaces On Implantable Biodegradable Polymer Scaffold., Nitin Garg
Bioengineering Theses
The technological advances in the field of MEMS and biodegradable polymers with elastomeric properties have opened new areas of application for engineering of soft tissues such as blood vessel, heart valves, cartilage, tendon, and bladder, which exhibit elastic properties. In this thesis work, Microfabrication technology has successfully been applied to biodegradable polymer films to encourage cell growth in designated area. This work is presented with the final goal of fabricating implantable polymer scaffolds to produce small diameter blood vessels in a controlled manner spatially by using the concept of wettability and contact guidance.There are several methods to control cell growth …
A New Paradigm In User Equilibrium - Application In Managed Lane Pricing, Asapol Sinprasertkool
A New Paradigm In User Equilibrium - Application In Managed Lane Pricing, Asapol Sinprasertkool
Civil Engineering Dissertations
Ineffective use of the High-Occupancy-Vehicle (HOV) lanes has the potential to decrease the overall roadway capacity during peak periods. Excess capacity in HOV lanes during peak periods can be made available to other types of vehicles, including single occupancy vehicles (SOV) for a price (toll). Such dual use lanes are known as "Managed Lanes." The main purpose of this research is to propose a new paradigm in user equilibrium to predict the travel demand for determining the optimal fare policy for managed lane facilities. Depending on their value of time, motorists may choose to travel on Managed Lanes (ML) or …
Corrosion And Leaching Study Of Low Copper (I) Oxide Paints For Antifouling Application, Hansika Parekh
Corrosion And Leaching Study Of Low Copper (I) Oxide Paints For Antifouling Application, Hansika Parekh
Material Science and Engineering Theses
Global environmental concern/economy challenges necessitate innovation of AFP's with novel additives offering improved corrosion protection, and biofouling resistance. Dispersing large proportions (40-70%) of Cu/Cu2O in paints although inexpensive produces excessive leaching & heavy accumulation of copper in marine. This study aims at formulating AFP's with reduced Cu2O levels along with novel additives, targeting controlled copper release around 15 ug/cm2/day. In the present study several formulations were prepared using Viscoplex (PAMA in mineral oil), Ionomer ED-SPAN and CuDDP. Substitute ocean water was prepared to simulate marine environmental conditions and perform leaching studies of different formulations. A variety of preliminary elimination tests …
Numerical Simulation Of Particle Adhesion Dynamics For Applications In Nanomedicine And Biosensing, Samar Shah
Numerical Simulation Of Particle Adhesion Dynamics For Applications In Nanomedicine And Biosensing, Samar Shah
Mechanical and Aerospace Engineering Theses
Multifunctional nanoparticles hold considerable promise as the next generation of medicine that allow for detection of early on-set of diseases and targeted therapy with minimal toxicity. To achieve targeted drug delivery, nanoparticles are usually functionalized with certain ligands (polymers) that bind specifically to a particular type of receptors on the endothelial cell surface, which are expressed exclusively during its diseased state. The ligand coated nanoparticles, loaded with drugs inside, transport in blood stream, and adhere to diseased cells via specific adhesion. However, this whole procedure becomes complicated due to simultaneous involvement of hydrodynamic force, adhesion force and Brownian force. In …
A Numerical Study On The Dynamics Of Bubble Growth And Detachment From An Orifice, Sheshi Kumar Takkallapally
A Numerical Study On The Dynamics Of Bubble Growth And Detachment From An Orifice, Sheshi Kumar Takkallapally
Mechanical and Aerospace Engineering Theses
The study of bubble formation from an orifice finds numerous industrial applications which include bubble acoustics in ocean physics and chemical reactors. Numerical simulations have been performed to investigate the dynamics of bubble formation, growth and detachment from an orifice. The full transient Navier - Stokes equation is solved in a two-dimensional axi-symmetrical coordinate system. The surface tension implementation algorithm known as the Pressure Boundary Method (PBM) is used to model the surface tension. The robustness of PBM method on Two-Phase flows with different conditions has been shown. The results achieved by numerical simulations have been compared with the available …
On The Design Of A Biodegradable Poc-Ha Polymeric Cardiovascular Stent, Joonas Ilmari Ponkala
On The Design Of A Biodegradable Poc-Ha Polymeric Cardiovascular Stent, Joonas Ilmari Ponkala
Mechanical and Aerospace Engineering Theses
The current state of the art in coronary stent technology is mainly populated by metallic stents usually coated with certain drugs to increase biocompatibility, even though experimental biodegradable stents have appeared in the horizon. To design stents from biodegradable polymers one must accurately characterize their mechanical behavior for analysis and optimization.This manuscript presents the process for evaluating the material properties for biodegradable biocompatible POC-HA polymeric composite, techniques for developing the stent models for finite element analysis, and development of material models for finite element analysis. The developed material models were utilized in finite element analysis to evaluate the suitability of …
Dynamic Stress From Transverse Impact On Flexural Beams, Joshua Ballard
Dynamic Stress From Transverse Impact On Flexural Beams, Joshua Ballard
Mechanical and Aerospace Engineering Theses
Accurate prediction of stress from impact would be very useful to an engineer in the design and analysis phases of a project. Currently one must resort to finite element analysis and experimentation, both of which have their negatives. Classical hand analysis methods such as the work-energy method overestimate the stress for a weight dropped onto the tip of a cantilevered beam. The goal of this project was to formulate analytical equations that were straightforward and easy to implement that would more accurately predict the dynamic stress in this scenario. Using the already derived equations from the work-energy method, a modification …
Algorithm Developement For Adaptive Grid Generation Using Galerkin Finite Element Method, Monalkumar Patel
Algorithm Developement For Adaptive Grid Generation Using Galerkin Finite Element Method, Monalkumar Patel
Mechanical and Aerospace Engineering Theses
The adaptive grid concept is developed in order to achieve more accurate and stable results for the numerical simulations of Partial Differential Equations (PDEs). There are two main types of strategies used for adaptive grids: local refinement by increasing the number of elements (h-refinement) and deforming grids where the number of elements remains fixed (r-refinement). The h-refinement method requires inserting additional elements and nodes in a certain region of the mesh. This significantly affects the software data structure and makes programming more difficult. To maintain the same data structure, the method must delete the same number of nodes from another …