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Cfd Based Design And Modelling Of Wind Fence To Mitigate High-Speed Wind Loading On A Modular Data Center, Devi Prasad Gorrepati

Mechanical and Aerospace Engineering Theses - Archive

A Modular Data Center (MDC) is a portable method of deploying a data center’s capacity. As an alternative to the traditional data center, an MDC can be placed anywhere data capacity is required. But this comes at the cost of making the MDC operable at any desired location with the environmental factors such as earthquakes and heavy winds. This study focuses on mitigating high-speed wind loading on the MDCs by designing a wind fence to reduce wind speed. Although wind fences are used in many agricultural and farming practices, their usage pertaining to MDCs is very limited. The challenge is …

Enhancement Of Fog-Collection Efficiency Of A Raschel Mesh Using Surface Coatings And Geometric Changes, Mithun Rajaram

Mechanical and Aerospace Engineering Theses - Archive

In a few countries, such as Chile, a Raschel mesh is widely used in the field to collect fog. In this work, we explored the possibility of enhancing fog-collection efficiency of a typical Raschel mesh through surface modification and geometric changes. We demonstrated about 100% enhancement in the fog-collection efficiency.

Tbi Induced Rate Dependent Viscoelastic Response Of Axon: Predictions From A Mathematical Model, Manikanta Jonnalagadda

Mechanical and Aerospace Engineering Theses - Archive

Traumatic brain injury (TBI) accounts to almost one fifth of total fatal injuries. Even though there are various mechanisms hypothesized for the causes leading to TBI, diffuse axonal injury (DAI) is found to be the most observed criterion. The reason for axonal failure in DAI has been studied extensively using experimental and computational models. It was found that axons behave like viscoelastic materials, thus exhibiting rate dependent behavior under loading. This viscoelastic behavior of axons is believed to drive the failure of axons and its substructures. It was observed that axon failure is caused by failures and distortions in axonal …

The Relationship Of Life Prediction For Quad Flat N0-Lead Package (Qfn )Packages Using 4 Point Bend Test And Thermal Cycle Testing, Monisha Mohan

Mechanical and Aerospace Engineering Theses - Archive

In the structural design of the Printed Circuit Boards, the stiffness modulus of the involved Fr4 and Cu layers play an important role. The 4 point bend test is one of the few test methods which is included in the JEDEC standard for the Monotonic Bend characterization for board level interconnects. The study in the past has shown that the damage mechanism of these two testing methods is similar. And also, correlation had been drawn by observation of failure mechanism through Scanning Electron Microscope (SEM). The purpose of this study is to create a methodology for co-relating 4 point bend …

Parametric Study Of An Igbt Cold Plate And Affect Of Device Level Modelling On System Level Thermal Predictions, Abhishek Raj Urs Kadaba Nagaraja Urs

Mechanical and Aerospace Engineering Theses - Archive

In power electronics, as there is continuous increase in performance of the electronic devices, simultaneously the size of the components used in these devices keep on decreasing. This has resulted in increased power densities and the requirements for excellent cooling as well in order to avoid the failure of those devices. Traditionally, while designing a cooling system for a device, uniform heat flux is assumed throughout the components. In many cases this method may not be accurate for a particular model design. There are chances that the heat flux distribution around the components are non-uniform and requires a more accurate …

Additive Manufacturing Methodologies For Multi Process And Multi Material Scenarios, Tushar Saini

Mechanical and Aerospace Engineering Theses - Archive

Additive Manufacturing processes have been developing and continuously improving but are primarily constrained to single materials, albeit some commercial multi extrusion 3D printers do exist where by it is possible to print with multi-colored fluidic polymers or at most two filaments of the same type. 3D printing an object with volumetric varying properties requires manual modification of the G-Code, not a feasible option considering the average size of G-Code generated by the slicing software. This research focuses on developing a post processing methodology that modifies the large G-Code files generated by the slicing software according to user requirements. The proposed …

Board Level Flexural Reliability Testing And Failure Analysis Of Printed Circuit Boards With Wcsp Packages, Guruprasad Shrikant Shinde

Mechanical and Aerospace Engineering Theses - Archive

Printed circuit boards, widely known as PCBs; are the skeleton behind every technology today. Electronics have integrated with every other engineering domain to improve the outcomes. It is very important that they remain intact in slightly extreme physical conditions. They are used in wide range applications which may lead to mechanical stress-strain in some conditions. There are various boards with different kinds of packages on them. A 0.7mm thick board with WCSP; Wafer chip scale package is a prime specimen for my work. The research includes designing exact replica of given PCB into ANSYS and its reliability testing. A 3-point …

Interface Reaction Induced Stress Development In An Aluminum Thin Film Copper Bulk Plate Diffusion Couple, Michael Codie Mishler

Material Science and Engineering Theses - Archive

This thesis investigates the mechanism of the interface reaction induced intermetallic phase formation (IMC) and its impact on the interface reliability in Al-Cu diffusion couple pairing. This study is motivated by the accelerated failure experiments in lead frame to integrated circuit (IC) package wire-bonds using copper (Cu) wire and aluminum (Al) bond-pad that have shown failure most often occurs at the interface of the intermetallic compound (IMC) γ2-phase (Cu9Al4). In order for simulative investigation, we created a diffusion couple consisting of Cu bulk plate coated pure Al thin films with thickness of ~2µm. This configuration is adapted to resemble the …

Influence Of The Volume-Contact Area Ration On The Growth Behavior Of The Cu-Sn Intermetallic Phase, Venkatakamakshi Supraja Giddaluri

Material Science and Engineering Theses - Archive

Solder Joints play a very important role in electronic packaging industry by serving as mechanical support and provides integrity to the device. The increasing demand for high performance, environmental and economic feasibility and miniaturization led to the development of high density interconnects. With the reduction in the size/stand off height of the solder is the reliability issues in the surface mount assemblies and packaging structures under various rigorous environments. One of the most important impact factors that affect the solder joint reliability is the growth rate IMC formed between the solder and substrate. IMC formation is required to ensure good …

Solution Processed Optical Coatings For Solar Cell Applications, Rajesh Tummala

Material Science and Engineering Theses - Archive

In the recent past the demand for higher energy conversion efficiency of solar cells is on the rise. Extensive research is carrying out and many new methods have been proposed by changing either fabrication process or implementation of anti-reflection coatings. In this thesis, the solution processed omni directional anti-reflection coatings have been demonstrated on commercial amorphous silicon solar cells and on fabricated organic solar cells. A simple convective coating technique is utilized to deposit spherical silica micro-particles on the commercial amorphous silicon solar cells and on fabricated organic solar cells. In order to investigate the behavior of solar cells at …

Evaluating And Augmenting Fuel-Saving Benefits Obtained In Aircraft Formation Flight, Wendy Awele Okolo

Mechanical and Aerospace Engineering Dissertations - Archive

When an aircraft flies, it generates wake vortices, which induce a non-uniform wind distribution in its wake. A trail aircraft, placed in the wake of a lead's aircraft vortices experiences this non-uniform wind distribution with varying directions and magnitudes, depending on the location within the wake. It has been demonstrated that there is a "sweet spot" within the wake of a leader in which a trail can experience upwash which leads to reduced drag. Through this mechanism, aircraft can save significant amounts of fuel by flying at the sweet spot of the lead aircraft's wake. This dissertation provides two metrics …

Evaluating The Impact Of Sustainable Built Environment Commitments And Outcomes On Respiratory Health: A Longitudinal Case Study Of Two Texas Cities, Megan Topham

Planning Dissertations - Archive

As population continues to grow the need for creating efficient and effective built environments that balance the three pillars of sustainability, environment, economic and equity, becomes even more pertinent. This exploratory research assisted in bridging the gap between understanding sustainable policy development and resulting impact on the corresponding outcomes, including influences from political culture. Followed by an overarching view of the changes in sustainable built environment outcomes over the course of nine years and how these outcomes influenced air quality measurements and inpatient asthma discharges. The case study methodology, established by Yin (2014), was utilized to address the research questions …

Moderating Effects Of Institutional Logics On Strategic Response To Coercive Institutional Change, Leon Paul Weeks

Business Administration Dissertations - Archive

Using institutional theory, the study examines the relationship between compliance behaviors and attitudes of small business owners and managers toward external coercive institutional change pressures. Organizations can experience conflicting institutional pressures (Pache & Santos, 2010). Variation in change pressures suggest heterogeneous impacts from institutional demands for change (e.g. Herremans, Herschovis, & Bertels, 2009). This study traces Internal Revenue Service regulatory, normative and cognitive-cultural changes targeting the tax preparation industry and examines the relationship between owner/managers attitudes about the changes and their compliance behaviors. Additionally this study traces the historical development of commercial and professional institutional logics in tax preparation and …

Progesterone And Prostaglandin F2Α Induce Species-Typical Female Preferences For Male Sexual Displays In Cope's Gray Treefrog (Hyla Chrysoscelis), J. L. Ward, E. K. Love, Alexander T. Baugh, N. M. Gordon, J. C. Tanner, M. A. Bee

Biology Faculty Works

Endocrine systems play critical roles in facilitating sexual behavior in seasonally breeding vertebrates. Much of the research exploring this topic has focused on the endocrine correlates of signaling behavior in males and sexual proceptivity in females. What is less understood is how hormones promote the expression of the often complex and highly selective set of stimulus–response behaviors that are observed in naturally breeding animals. In female frogs, phonotaxis is a robust and sensitive bioassay of mate choice and is exhibited by gravid females during the breeding season. In stark contrast, females exhibit low phonotactic responsiveness outside the breeding season, but …

Magnetic Resonance Imaging Of Cerebrovascular Reactivity Using Gas Inhalation Challenges, Harshan Ravi

Bioengineering Dissertations - Archive

Cerebrovascular reactivity (CVR) is a measure of dilation capacity of cerebral vasculature. It is an important biomarker for the vascular functionality and integrity, and may have clinical indications in stroke, atherosclerosis, Moyamoya disease, multiple sclerosis, brain tumor, and other neurological disorders. The most commonly used approach to measure CVR is by applying a physiological maneuver to alter the arterial carbon dioxide (CO2) concentration (e.g. inhaling a small amount of CO2 which is a potent vasodilator), while continuously acquiring BOLD MR images. However, the current method suffers from several limitations related to specificity, sensitivity, and physiological modeling of the measured signal. …

Improving Water Quality Forecasting Using Data Assimilation, Hamideh Riazi

Civil Engineering Dissertations - Archive

Population growth increases agricultural, industrial and human activities which threaten the quality of water resources, especially water supply sources such as lakes and reservoirs. In potentially high-impact situations such as algal blooms, active measures such as controlled release from reservoirs may be necessary. To minimize release while meeting the water quality requirements, accurate short-range water quality forecast is necessary. Because watershed water quality models have a large number of state variables most of which are never observed, their initial conditions (IC) are subject to large uncertainties which may propagate into large forecast errors. In this research, a data assimilation (DA) …

Students At Risk: The Impacts Of Self-Efficacy And Risk Factors On Academic Achievement, Candice L. Cooper

Educational Leadership & Policy Studies Dissertations - Archive

School dropout continues to be a societal and educational concern today. There are various eligibilities which identify students as being at risk for school dropout. This study uses the Educational Longitudinal Survey of 2002 (ELS:2002) and its definition of the term 'at risk' to explore the impacts of varying levels of risk, students self-beliefs, and the level of effort and persistence applied to academic tasks on level of educational attainment by age 26 in at-risk youth. ELS:2002 data is used to select the final study sample (n=4,002). This study demonstrates that the level of risk (i.e., number of at-risk factors …

Landfill Volume Gain From The Diversion Of Construction And Demolition Waste, Aayush Raj Tiwary

Civil Engineering Theses - Archive

Construction and Demolition (C&D) waste is one of the major components of the solid waste and is defined as a waste stream resulting from the construction, renovation and demolition of structures such as buildings, roads, and bridges. The amount of C&D waste has been in an upsurge with rapid growth in construction works and is expected to grow even more. As such, the effective waste management for C&D disposal has been a global issue owing to the increasing construction works worldwide. Although landfill disposal of C&D waste is not the preferred method of the C&D waste management, a significant portion …

Estimation Of Rebar Corrosion In Concrete Using Ground Penetrating Radar, Rakesh Krishnarajapete Raju

Civil Engineering Theses - Archive

The purpose of this research was to quantitatively relate the amount of rebar corrosion in concrete with the amplitude of electromagnetic waves generated from Ground penetrating radar (GPR). Many studies have been undertaken on qualitative measurement of corrosion, but there are very few studies regarding estimation of rebar corrosion quantitatively. This experiment involved the use of accelerated corrosion by impressed current technique to corrode the rebar inside the concrete and GPR to determine the extent of corrosion, while making a comparison with a stainless steel bar which was used as a cathode to create a galvanic cell action. Rebars were …

Resources, Innovative Outcomes, And The Symbolic And Substantive Performance Of Entrepreneurial Firms: An Examination Of Independent Popular Music Artists, John A. Deleon

Management Dissertations - Archive

The importance of innovation to the success of entrepreneurial firms has been well established in prior work. Yet, important gaps still remain. I draw from the innovation literature, the resource-based view, and institutional theory in order to address how entrepreneurial firms are able to find success through innovation in competitive environments. Specifically, following Penrose’s (1959) approach to the resource-based view, I argue that two resource categories, creativity-related resources and management-related resources, form antecedent conditions for innovative outcomes. I divide these innovative outcomes into two separate components, innovative output and innovative uniqueness. Further, I argue that innovative output and innovative uniqueness …

Improving The Rainfall And Flood Frequency Analyses Using Stochastic Storm Transposition Method, Morteza Kiani

Civil Engineering Theses - Archive

Reproduction and realization of historical rainfall events provides foundations for flood and rainfall frequency analyses and the advancement of meteorological studies. Stochastic storm transposition (SST) is a method for such a purpose and enables us to perform frequency analyses by transposing observed historical storm events over any given watershed. The goal of this study is to stochastically examine the impacts of extreme events on all locations in a homogeneity zone. Storms with the same probability of occurrence on a defined homogenous neighborhood will generate various impacts due to spatial and temporal variations of the storms. Transposing storms occurring in the …

Slope Stabilization And Performance Monitoring Of I-35 And Sh-183 Slopes Using Recycled Plastic Pins, Sandip Tamrakar

Civil Engineering Theses - Archive

The United States earth retaining structure market exceeds 170 million square feet annually and there are over 50 different retaining systems to select from which are unique in design and construction. Depending on the type of retaining structure, unit costs vary from less than $20 to in excess of $250 per square foot. Selecting the technically appropriate and cost-effective system is often critical to project cost and schedule. The Recycled Plastic Pin (RPP) has potential to be utilized as a sustainable and cost effective option to stabilize the surficial slope failure. RPP have been successfully used in Missouri, Iowa and …

Experimental Study On Seismic Performance Of Reinforced Concrete Coupling Beams And Rectangular Squat Walls With Innovative Reinforcement Configurations, Poorya Hajyalikhani

Civil Engineering Theses - Archive

Reinforced concrete core walls, coupled by diagonally reinforced coupling beams (DCBs), are a very efficient seismic force resisting system for medium- to high-rise buildings. The diagonal reinforcing bars in DCBs are most effective when the beam has a span-to-depth ratio, ln/h, less than 2. Modern construction, due to architectural requirements, typically requires span-to-depth ratios between 2.4 to 4, which leads to a very shallow angle of inclination of the diagonal reinforcement (generally between 10 to 20 degrees). The lower angles of inclination, combined with the detailing requirements specified in ACI 318, results in reinforcement congestion as well as design and …

Characterization And Comparison Of Fresh And Landfilled Solid Waste, Kavya Koganti

Civil Engineering Theses - Archive

The understanding of the characteristics of Municipal Solid Waste (MSW) is very important in planning, designing and operating and/or upgrading the landfill operation system. It is well anticipated that the fresh MSW will be different from the landfilled MSW due to degradation. However, there is no systematic study on the comparison of physical properties of fresh and landfilled waste from bioreactor and/or enhanced leachate recirculated (ELR) landfills. The most important MSW properties to be considered while planning a landfill system are physical composition, moisture content, unit weight and volatile solids content. These properties are of particular interest especially when an …

Thermo-Hydro-Mechanical Behavior Of Unsaturated Clayey Soils Via Thermo/Suction-Controlled Ring Shear Testing, Jairo Edmundo Yepes Heredia

Civil Engineering Dissertations - Archive

There is a lot of geotechnical infrastructure made of compacted soil, or resting on unsaturated ground, which involves a wide range of deformations. Calculation of foundation settlement, for instance, requires a good estimation of soil stiffness at relatively small strains. Analysis of natural and engineered earth slopes, embankments, and soil bearing capacity, on the other hand, requires good estimations of shear strength, from peak to residual. Besides, despite the critical importance of the thermo-mechanical behavior of unsaturated soils in many geotechnical applications, the effect of relatively high temperature on shear strength and stiffness properties of unsaturated soils is not yet …

The Role Of Platelets In The Successful Closure Of The Ductus Arteriosus In Premature Infants After Indomethacin Treatment, Joan Heilskov

Nursing Dissertations - Archive

Premature birth (birth before 37 weeks gestation) remain a global problem with negative consequences profundly affecting the infants, their families, and society. Persistent patent ductus arteriosus (PDA) is a significant complication seen in preterm infants. Premature infants with persistent PDAs are at increased risk for morbidity and mortality. Indomethacin is reported to successfully close the PDA in only 20-40 percent of infants whose birth weights are less than 1,000g. Common side effects of Indomethacin include renal dysfunction, gastric perforations, and decreased cerebral blood flow and perfusion. Several studies have shown thrombocytopenia is associated with persistent PDA in premature infants who …

Predictors Of Persistence In Online Graduate Nursing Students, Denise Cauble

Nursing Dissertations - Archive

Persistence is an important measure of success for individual students and institutions of higher learning. The purpose of this study was to explore personal and academic factors that influence persistence in online graduate nursing students. A predictive correlational study design was used. Data were extracted from existing student records in two online graduate programs within a large, urban college of nursing. A sample size of 197 graduate nursing students was selected, 94 who persisted to graduation from their program within 36 months and 103 who did not. Age, gender, race/ethnicity, undergraduate GPA, undergraduate education (BSN or RN-BSN level) were examined …

Characterization Of The Constituent Mineral Components Of North African Surface Dust Samples Utilizing Computer Controlled Scanning Electron Microscopy (Ccsem), Zakariah Edward Sabatka

Earth & Environmental Sciences Theses - Archive

Analysis of the constituent mineral components of surface dusts/soils from Chad-Niger region, North Africa, was undertaken by computer controlled scanning electron microscopy (CCSEM) to determine if differences in composition could be used for source attribution to distinguish windblown material from different contributing source areas. A total of 11 surficial samples were selected for analysis by computer controlled scanning electron microscopy (CCSEM). These samples were from two different geographic locations in the Chad-Niger region. CCSEM analysis generates data on individual dust particles that includes: particle size, shape, and chemical composition. This type of particle characterization used a Scanning Electron Microscope (SEM) …

Enhancement Of Knowledge And Skills Of Community Midwives In Sindh, Pakistan, Sadia Abbas Ali, Arusa Lakhani, Rafat Jan, Shahnaz Shahid, Marina Baig, Farzana Adnan

Journal of Asian Midwives (JAM)

With a maternal mortality rate of 276 deaths per 100,000 live births, Pakistan is one of the countries with a large share in the percentage of world’s maternal mortality. As an intervention for the Millennium Development Goals (MDG) 4 and 5, the World Health Organization (WHO) strongly suggests that skilled care before, during, and after childbirth can save the lives of women and newborn babies. One of the interventions to ensure care to mothers and babies by skilled care providers is the capacity building training of Community Midwives (CMWs) aiming to improve their midwifery competency.

One such training intervention was …

Another Year Over …., Rafat Jan, Edwin Van Teijlingen

Journal of Asian Midwives (JAM)

No abstract provided.