Engineering Commons^™

Increasing The Supply Of Affordable Housing In Urban India - Mumbai, Upasna Viswanathan

Open Access Theses

The need for housing in today's world is irrefutable. The growing population, accompanied with the fast pace of urbanization, are producing great housing demand, in urban areas in particular. This study focused on one segment of housing - affordable housing, in Mumbai, India, the demand for which has been on a steady rise over the past decade. Though traditionally the State was the provider of affordable housing, private sector has been increasingly involved in the segment, beginning the economic meltdown of 2008-2009. Yet there is a huge demand-supply gap that exists, which needs to be filled. The researcher looks at …

Characterization Of Thermal And Mechanical Properties Of Porous Material For Electronic Cooling Applications, Ninad Tushar Trifale

Open Access Theses

Metal foams are considered beneficial for several applications because of its significantly large surface area for a given volume. Foams form a high thermal conductive network in a thermal interface for electro cooling applications. The porous structures are relatively compliant and can provide for a better contact and thereby have a lower thermal resistance. Porous heat sinks made of aluminum foam have been well studied in the past. It is not only cost effective due to the unique production process, but also attractive for the theoretical modeling study to determine the performance. A study on the thermal and mechanical characterization …

Effects Of Crossflow In An Internal-Cooling Channel On Film Cooling Of A Flat Plate Through Compound-Angle Holes, Zachary Taylor Stratton

Open Access Theses

The film-cooling holes in turbine blades are fed from an internal cooling channel. This channel imposes a crossflow at the entrance of the holes that can significantly affect the performance of the cooling jets that emanate from those holes. In this study, CFD simulations based on steady RANS with the shear-stress transport (SST) and the realizable k -ε turbulence models were performed to study film cooling of a flat plate with cooling jets issuing from eight round holes with a compound angle of 45 degrees, where the coolant channel that fed the cooling jets was oriented perpendicular to the direction …

A Farm Management Information System With Task-Specific, Collaborative Mobile Apps And Cloud Storage Services, Jonathan Tyler Welte

Open Access Theses

Modern production agriculture is beginning to advance beyond deterministic, scheduled operations between relatively few people to larger scale, information-driven efficiency in order to respond to the challenges of field variability and meet the needs of a growing population. Since no two farms are the same with respect to information and management structure, a specialized farm management information system (FMIS) which is tailored to the realities on the ground of individual farms is likely to be more effective than generalized FMIS available today.

This thesis presents the design of a FMIS using proven user-centered design principles. This approach resulted in the …

Retrofiting Lid Practices Into Existing Neighborhoods: Is It Worth It?, Timothy Wright

Open Access Theses

Low impact development (LID) practices are gaining popularity as a way to manage stormwater close to the source. This reduces infrastructure requirements and helps to maintain hydrologic processes close to predevelopment conditions. Studies have shown LID practices to be effective in reducing runoff and improving water quality. However, little has been done to aid decision makers in selecting the most effective practices for their needs and budgets.

To this end, the L-THIA LID model has been applied. Using readily available data sources, multiple scenarios can quickly be examined, and then analyzed to determine the cost of implementation and the approximate …

An Analysis On Causes Of Late Final Payment And Release Of Retainage: Electrical Subcontractors’ View, Xuejing Zhang

Open Access Theses

Using the survey approach, this study identified the underlying causes of late payments and release of retainage for electrical subcontractors, attempting to answer the questions, "What were the minimum, maximum and average delay days of final payment and release of retainage?", "What were the rank of factors in terms of significance on delaying final payment and release of retainage?", and "What were the rank of factors in terms of frequency on delaying final payment and release of retainage?" A survey questionnaire was developed and distributed to about 150 professionals in electrical subcontractors. 29 reports were collected. Based upon the analysis …

Effect Of Multivalent Ions On The Swelling And Mechanical Behavior Of Superabsorbent Polymers (Saps) For Mitigation Of Mortar Autogenous Shrinkage, Qian Zhu

Open Access Theses

The chemical and physical structure-property relationships of model superabsorbent polymer (SAP) hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+ , Ca2+ , and Al3+ ). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt.%) and covalent crosslinking densities of 1, 1.5, and 2 wt.%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels …

The Influence Of Gaps On The Frequency Response Of A Beamspring Contact System, Wenbin Zhang

Open Access Theses

Some mechanical systems with gaps such as in disc brakes and Cardan joints exhibit nonlinearity under certain load conditions, which is unpredictable and highly sensitive to initial conditions. Previous studies were mainly focused on either a single-degree-of-freedom (DOF) system or a flexible beam with uniform elastic foundation. The analysis of this thesis is a combination of these two where gaps are first introduced to a flexible beam model. A model of a beam resting on compliant foundation with gaps has been developed and analyzed. The assumed modes method is used to derive the equations of motion (EOM's) for the system. …

No And No2 Modeling For Diesel Oxidation Catalyst At Different Thermal Aging Levels, Keqin Zhou

Open Access Theses

Different DOC modeling methods are analyzed and compared. Detailed reaction mechanisms of DOC reaction are discussed and a new NO and NO2 modeling technique is proposed. Experiments are conducted measuring downstream DOC NO and NOx . DOC out NO and NO2 concentrations are modeled as a function of DOC temperature. A robust model is built such that with the input of real time NOx and DOC temperature information, DOC-out NO and NO2 concentrations can be precisely predicted.

As is true with many catalysts, the DOC thermally ages as it operates, which reduces the thermal effectiveness level of the catalyst. This …

The Effect Of Job Performance Aids On Quality Assurance, Erik David Fosshage

Open Access Theses

Job performance aids (JPAs) have been studied for many decades in a variety of disciplines and for many different types of tasks, yet this is the first known research experiment using JPAs in a quality assurance (QA) context. The objective of this thesis was to assess whether a JPA has an effect on the performance of a QA observer performing the concurrent dual verification technique for a basic assembly task. The JPA used in this study was a simple checklist, and the design borrows heavily from prior research on task analysis and other human factors principles. The assembly task and …

Microstructural Indicators Of Transition Mechanisms In Time-Dependent Fatigue Crack Growth In Nickel Base Superalloys, Ann Elizabeth Heeter

Open Access Theses

Gas turbine engines are an important part of power generation in modern society, especially in the field of aerospace. Aerospace engines are design to last approximately 30 years and the engine components must be designed to survive for the life of the engine or to be replaced at regular intervals to ensure consumer safety. Fatigue crack growth analysis is a vital component of design for an aerospace component. Crack growth modeling and design methods date back to an origin around 1950 with a high rate of accuracy. The new generation of aerospace engines is designed to be efficient as possible …

Characterizing The Intra-Warp Address Distribution And Bandwidth Demands Of Gpgpus, Calvin Holic

Open Access Theses

General-purpose Graphics Processing Units (GPGPUs) are an important class of architectures that offer energy-efficient, high performance computation for data- parallel workloads. GPGPUs use single-instruction, multiple-data (SIMD) hardware as the core execution engines with (typically) 32 to 64 lanes of data width. Such SIMD operation is key to achieving high-performance; however, if memory demands of the different lanes in the "warp" cannot be satisfied, overall system performance can suffer.

There are two challenges in handling such heavy demand for memory bandwidth. First, the hardware necessary to coalesce multiple accesses to the same cache block--a key function necessary to reduce the demand …

An Algorithm For Impacting Soft Structures, Tengfei Long

Open Access Theses

Impact among soft structures is often difficult to model because of the geometrical non-linearity involved. There are a number of previous studies of the contact dynamics of rigid bodies, but few has focused on soft structures so far.

This thesis models impact between soft structures without any restraint on their geometries. The goal is to simulate the dynamics involved among soft structures during an impact process. This has been done through designing and implementing an contact algorithm that uses the finite element method along with a three-dimensional solid element to solve the fundamental time integration problem. Modeling of the contact …

Exhaust Thermal Management Using Cylinder Deactivation And Late Intake Valve Closing, Mark E. Magee

Open Access Theses

Progressively stricter emission regulations have compelled diesel engine manufacturers to develop new technologies that reduce harmful pollutants like NOx and soot. While manufacturers have previously been able to meet these regulations through the use of on engine technology such as exhaust gas recirculation and multiple pulse injections, exhaust after treatment systems such as diesel particulate filters and selective catalytic reduction systems have become necessary to meet recent stricter policies. While these after treatment systems are incredibly effective at reducing harmful emissions, to operate effectively the system needs to be above a certain temperature level typically between 250 and 300°C. Many …

Comparison Of A Sierpinski Gasket Monopole Antenna To Bow-Tie Antennas Based Off The Fractal Iterative Shapes, Kyle Nathan Murg

Open Access Theses

Antennas are an integral part of mobile devices. Recently, the demand for smaller phones has increased requiring smaller components within the device. This leads to problems with performance and limitations of RF systems within mobile devices including antennas which have been affected by the size thus affected frequency output. In this thesis, fractal theory will be utilized to compare the performance of the Sierpinski Gasket Monopole antenna to single band antennas to see if this is a viable substitute in mobile applications. By utilizing simulations and physical antennas, the performance will be observed at each frequency band and compared.

Improving Indoor Air Quality Through Botanical Air Filtration In Energy Efficient Residences, Daniel William Newkirk

Open Access Theses

According to the U.S. EPA, the average American spends 90% of their time indoors where pollutants are two to five times more prevalent than outside. The consequences of these pollutants are estimated to cost the U.S. 125 billion dollars in lost health and productivity. Background literature suggests botanical air filtration may be able to solve this problem by leveraging the natural ability of plants to purify indoor air. By improving indoor air quality, energy consumption can also be reduced by bringing in less outside air to dilute contaminants within the space. A botanical air filter, called the Biowall, was designed …

Nanohub Database Analysis: Using Anomaly Detection Method And Principal Component Analysis, Mengyang Qi

Open Access Theses

This thesis analyzes usage data from nanoHUB.org, which is a web-based infrastructure for e-collaboration among nanotechnology simulation community. Previous analysis of nanoHUB database showed he nanoHUB usage data follows an unknown, heavy-tailed distributions. This thesis extends the analysis and develops an automatic anomaly detection method based on piece-wise linear approximation. The anomaly here refers to collective user behaviors different from others. The result shows that the method can accurately detect the anomalies in the unknown, heavily detailed distribution. This thesis also applies anomaly detection method and principal component analysis to other databases in nanoHUB and successfully reveals differences between different …

Modeling Preventive Maintenance In Complex Systems, Jessica Rivas

Open Access Theses

This thesis presents an explicit consideration of the impacts of modeling decisions on the resulting maintenance planning. Incomplete data is common in maintenance planning, but is rarely considered explicitly. Robust optimization aims to minimize the impact of uncertainty--here, in contrast, I show how its impact can be explicitly quantified. Doing so allows decision makers to determine whether it is worthwhile to invest in reducing uncertainty about the system or the effect of maintenance. The thesis consists of two parts. Part I uses a case study to show how incomplete data arises and how the data can be used to derive …

Biaxial Shear/Tension Failure Criteria Of Spectra Single Fibers, Jianzhuo Sun

Open Access Theses

An experimental study was conducted to develop the biaxial failure surface criteria of single Spectra 130d and 100d filaments in a torsion-tension environment. The cross-sectional profiles of single Spectra fibers were investigated using scanning electron microscopy and X-ray computed tomography. A pin-gripping method to fix the ends of a polyethylene single fiber was developed. Effects of pin diameter on failure stress for both Spectra 130d and 100d were characterized. It was found that the perturbed stress field effect can be neglected when the pin diameter is larger than 0.8 mm. Additionally, the effect of the sample's gage length on fiber …

Effectiveness Of Air Sealing Measures And Other Energy Retrofit Measures In Lafayette Energy Improvement Program, Jia Ye

Open Access Theses

From September 2011 to March 2013, the City of Lafayette, IN implemented Lafayette Improvement Program. The goal of this project was to "increase energy efficiency of existing homes through retrofitting, thereby lowering the costs of home ownership within the Vinton and Glen Acres Neighborhood Target Area (The City of Lafayette, 2011)." Energy audit companies carried out before blower door test and after blower door test to identify air tightness of subjects. This paper finds out there was an improvement in air tightness in the population of 85 houses and the degree of improvement was between 16.85% and 17.85%.

Change point …

Lab-Scale Fast-Hydropyrolysis And Vapor-Phase Catalytic Hydrodeoxygenation For Producing Liquid Fuel Range Hydrocarbons From Intact Biomass, Vinod Kumar Venkatakrishnan

Open Access Dissertations

Liquid transportation fuels are primarily produced from petroleum-based non-renewable carbon sources. Sustainably available lignocellulosic biomass, as a renewable form of atmospheric carbon, could be utilized to produce hydrocarbon-based fuels with high energy density. One of the process options for this conversion is the H2Bioil process, where biomass is rapidly heated in a hydrogen environment to produce fast-hydropyrolysis vapors that are catalytically upgraded in downstream hydrodeoxygenation (HDO) to produce hydrocarbons. This process has been modeled to have high carbon and energy efficiencies of ~70% and ~75%, respectively.

This dissertation presents the results of a lab-scale experimental proof-of-concept for the H2Bioil process …

Multiscale Modeling Study Of Methanol Oxidation By Ion-Modified Mdh Enzymes, Purnima Kharidehal

Doctoral Dissertations

Enzymes have been considered as molecular electrocatalysts due to their extraordinary characteristics such as their ability to accelerate reactions enormously, to operate under physiological conditions, and to produce fewer by-products during a catalytic reaction. However, enzyme based fuel cells have been reported to have power output and stability limitations, which are restricting the use of this kind of fuel cell to small electronic devices. Methanol dehydrogenase (MDH) is one such enzyme, which oxidizes methanol and other primary alcohols to their corresponding aldehydes. The active site of MDH contains a divalent cation (Ca2+), a co-factor pyrrolo-quinoline quinone (PQQ), several amino acids, …

System Analysis With Improved Thermo-Mechanical Fuel Rod Models For Modeling Current And Advanced Lwr Materials In Accident Scenarios, Ian Edward Porter

Theses and Dissertations

A nuclear reactor systems code has the ability to model the system response in an accident scenario based on known initial conditions at the onset of the transient. However, there has been a tendency for these codes to lack the detailed thermo-mechanical fuel rod response models needed for accurate prediction of fuel rod failure. This proposed work will couple today's most widely used steady-state (FRAPCON) and transient (FRAPTRAN) fuel rod models with a systems code TRACE for best-estimate modeling of system response in accident scenarios such as a loss of coolant accident (LOCA). In doing so, code modifications will be …