Engineering Commons^™

Effects Of Nitrogen Deposition And Empirical Nitrogen Critical Loads For Ecoregions Of The United States, Linda H. Pardo, Mike E. Fenn, Christine L. Goodale, Linda. H. Geiser, Charles T. Driscoll, Edith B. Allen, Jill S. Baron, Roland Bobbink, Williams D. Bowman, Christopher M. Clark, Bridget Emmett, Frank S. Gilliam, Tara L. Greaver, Sharon J. Hall, Erik A. Lilleskov, Lingli Liu, Jason A. Lynch, Knute J. Nadelhoffer, Steven S. Perakis, Molly J. Robin-Abbott, John L. Stoddard, Kathleen C. Weathers, Robin L. Dennis

Civil and Environmental Engineering - All Scholarship

Human activity in the last century has led to a significant increase in nitrogen (N) emissions and atmospheric deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the deposition of pollution that would be harmful to ecosystems is the determination of critical loads. A critical load is defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge.

The objectives of this project were to synthesize …

Bayesian Compressed Sensing Based Dynamic Joint Spectrum Sensing And Primary User Localization For Dynamic Spectrum Access, Xue Li, Steven Hong, Zhu Han, Zhiqiang Wu

Electrical Engineering Faculty Publications

In cognitive radio (CR) and dynamic spectrum access (DSA) network research, most of current work on spectrum sensing focuses on the detection of existence of the spectrum holes for secondary user (SU) to harness. However, in a more sophisticated CR, the SU needs to detect more than just the existence of primary users (PUs) and spectrum holes: e.g., the transmission power and location of the primary users. In our previous work, we combined the spectrum sensing and PU power/localization detection together, and developed a joint PU detection and power/localization detection algorithm via compressed sensing (CS). By employing compressed sensing, the …

Crystallite Phase And Orientation Determinations Of (Mn, Ga) As/Gaas-Crystallites Using Analyzed (Precession) Electron Diffraction Patterns, Ines Häusler, Stavros Nicolopoulos, Edgar F. Rauch, K. Volz, Peter Moeck

Physics Faculty Publications and Presentations

Outline of the presentation:

1. Material system: (Mn,Ga)As/GaAs-crystallites

2. Structure analysis using Nano-beam Diffraction (NBD) Precession Electron Diffraction Technique (PED) --> Structure type I + II

3. Phase and orientation mapping using ASTAR

4. Conclusion

Qos-Aware Fine-Grained Power Management In Networked Computing Systems, Jiayu Gong

Wayne State University Dissertations

Power is a major design concern of today's networked computing systems, from low-power battery-powered mobile and embedded systems to high-power enterprise servers. Embedded systems are required to be power efficiency because most embedded systems are powered by battery with limited capacity. Similar concern of power expenditure rises as well in enterprise server environments due to cooling requirement, power delivery limit, electricity costs as well as environment pollutions.

The power consumption in networked computing systems includes that on circuit board and that for communication. In the context of networked real-time systems, the power dissipation on wireless communication is more significant than …

Extension Of A Progressive Failure, Energy Dissipation, Composite Tailoring Concept To A Healing Configuration, Shailesh Jayant Divey

Material Science and Engineering Theses - Archive

A composite failure tailoring concept that results in a yield type response under tension has been proposed, modeled, and experimentally verified in prior research. The concept capitalizes upon a sequential, progressive failure of a set of redundant load paths of tailored strength and length. It has been shown in prior publications that the concept is functional and by comparison with experimental results that the analytical models of response developed are accurate. The limits of performance of the proposed tailoring concept have recently been investigated via a parametric study using one of the response models developed and significant improvements have been …

Preliminary Design Of A Pressurization System For Small Bipropellant Rocket Engines, Steven Stanley

Mechanical and Aerospace Engineering Dissertations - Archive

A study was conducted on the feasibility of developing a device or system that would improve the performance of small, bipropellant rockets through pressurization of the propellants. Due to the limitations in the space industry, namely high development costs and resistance to change, the new approach needed to be as simple and robust as possible. After reviewing several different potential methodologies, a concept was developed from first principles based on small gas turbine engine fuel injection approaches. The concept is simple and has heritage in the field of gas turbine engines, but it is new for the field of rocket …

Analysis Of Pulse Detonation Turbojet Engines, Ronnachai Vutthivithayarak

Mechanical and Aerospace Engineering Dissertations - Archive

Research over the last two decades has shown the potential advantages of pulse detonation engines (PDEs) over existing aero-engines in terms of improved thermodynamics efficiency, improved thrust performance, simplicity of design, and exibility to operate over a wide speed range. The inherently unsteady characteristic of PDEs makes it difficulty to analyze and evaluate their performance. The conventional method that relies on steady-state assumptions cannot be directly applied. PDE studies have to employ unsteady gasdynamics behavior. In this study, the thermodynamic cycle of a PDE, which can be called the ZND cycle, is theoretically analyzed. A parametric analysis of turbojet PDEs …

Mode Truncation Analysis In Forced Response Of Structural Dynamics, Sravan Kumar Neela

Mechanical and Aerospace Engineering Theses - Archive

Mode truncation in Modal analysis is an important problem and should be addressed with an effective truncation criterion. The truncation errors are considered as error forces and these error limits can be used to select the number of modes in the solution. Usually frequency based approach is used in selection of modes. But this method ignores the error forces in truncation and not effective if the cutoff frequency is greater than highest natural mode. An effective criterion would limit error forces, thereby minimizing errors in the response solution. To overcome the inaccuracies due to truncation, Mode Truncation Augmentation was used …

Experimental And Numerical Investigation Of Transesterification Of Vegetable Oil With A Continuous Flow Capillary Reactor, Rachaneewan Charoenwat

Mechanical and Aerospace Engineering Dissertations - Archive

Biodiesel, Fatty Acid Methyl Ester (FAME), is a renewable fuel that is a promising alternative to fossil fuels in the future. Biodiesel not only has similar properties to diesel derived from fossil fuel, but it also provides more environmentally friendly due to lower carbon monoxide and sulfur emissions. Biodiesel is composed of methyl esters which can be synthesized from various fatty acid sources with a present of catalyst. Typical feed-stocks include vegetable oils, such as waste cooking oil, animal fats, and even oil from algae. Four primary ways to use vegetable oil as a fuel are direct use, blending with …

Modeling And Control Of Automatic Transmission With Planetary Gears For Shift Quality, Patinya Samanuhut

Mechanical and Aerospace Engineering Dissertations - Archive

Automatic transmission is a major component in a vehicle that transmits the power source from the engine to the drive wheels of the vehicle. To improve fuel economy, reduce emission and enhance driving performance, many researchers have made tremendous efforts on new technologies for automatic transmission with planetary gear sets. Among these new technologies, system dynamics and control methodologies are extremely important tools to realizing the fuel economy, emission and driving performance. This research effort focuses on the modeling and control of an automatic transmission with planetary gear sets. A Lagrange-based method is developed to derive the equations of motion …

Buckling Analysis Of Thin Plates With Or Without A Hole Under Arbitrary Boundary Conditions Using The Galerkin Method, Srider Thirupachoor Comerica

Mechanical and Aerospace Engineering Theses - Archive

This thesis demonstrates how to find the critical buckling load value of thin plates with or without a hole under different boundary conditions using the Galerkin method. The use of symbolic software is essential due to the lengthy computations involved because of the complexity of the problems. Firstly, the lateral deflection of the plate is expressed in a series of polynomials each of which satisfies the given boundary conditions. Then by using the Galerkin method, the coefficients of these polynomials are found and with the help of symbolic algebra system, the matrices for the corresponding eigenvalue problem are built from …

Xanes And Ftir Study On Dried And Calcined Bones, Jayapradhi Rajendran

Material Science and Engineering Theses - Archive

The animal bones are common archeological finds and are helpful in understanding the human past. The bones undergo transformation when they are calcined. The cooked and cremated bones undergo different transformation, because of their difference in their temperatures. Various techniques are employed to characterize the bone. In this study, XANES and FTIR are used to characterize the dried and calcined bones of different species. The calcined bones are prepared at two different temperatures, which helps in understanding the difference between the cooked and cremated bones. The objective of this research is to comprehend the chemical property of the bone material …

A One Dimensional Dry Friction Microconveyor Platform: Modelling And Analysis Of Micropart Motion Due To Surface Excitation, Moshin Rizwan

Mechanical and Aerospace Engineering Dissertations - Archive

Many approaches are used for micropart manipulation ranging from individual pick and place to manipulation through a workcell comprising of arrays of actuators. Existing approaches provide discrete actuation and have limitations on the lower bound on the size of the micropart to be handled. In this research, the active surface concept for non-contact micropart manipulation is investigated. The active surface deformation is generated by a set of controlled microactuators and provides for continuous micromanipulation while alleviating limitations of existing approaches. The drastic increase of surface area to volume ratio from macroscale to microscale requires the consideration of surface forces (such …

Electrodeposition Of Nickel Sulfide And Its Thermal Oxidation For Photovoltaic Applications, Munteha Pac

Material Science and Engineering Theses - Archive

Alternative photovoltaic materials that feature natural abundance, low extraction and processing costs, and reasonable efficiency have to be found. In this respect, transition metal chalcogenides such as oxide and sulfide compounds of Ni; is studied because in addition to the features like abundance and cost, its electronic and optical properties vary dramatically by modifications in its stoichiometry. In addition to its low cost, and mature technology, electrochemical deposition method has many advantages over other methods since it allows direct deposition on conducting substrate and achieves good electrical contact and precise control of film thickness. Process of manufacturing Nickel Oxysulfide compound …

High Speed Edgewise Rotor Computational Analysis And Optimization At High Inflow Velocities Achieved Through Forward Mast Tilt, Cory Michael Hitte

Mechanical and Aerospace Engineering Theses - Archive

Increased forward flight speed has long been the desire of the rotorcraft industry. Novel designs, such as compounds and tilt rotors have allowed for speed envelope expansion, but not without incurring performance hindrances unique to each configuration. Designs that utilize low disc loading edgewise rotors, which offer efficient flight at high speeds while maintaining hover performance, are desirable. Such designs require increased flapping capability and/or mast tilt in order to achieve the necessary thrust orientation required for overcoming aircraft drag. The combination of speed and thrust vector inclination yields a relatively undocumented region of rotorcraft performance. In particular, the effects …

Synthesis And Characterization Of Platinum Based Catalysts For Fuel Cells, Sonam Patel

Material Science and Engineering Theses - Archive

Platinum (Pt) and platinum alloys have attracted wide attention as catalysts to attain high performance to increase the power density and reduce the component cost of polymer electrolyte membrane fuel cells (PEMFCs). Extensive research has been conducted in the areas of new alloy development and understanding of mechanisms of electrochemical oxygen reduction reaction (ORR). The durability of PEMFCs is also a major barrier to the commercialization of these fuel cells. Recent studies have suggested that potential cycling can gradually lead to loss of active surface area due to Pt dissolution and nanoparticle grain growth [1]. In this thesis we report …

Gold/ Copper Sulphide And Gold Nanoparticles For Application In Cancer Therapy, Santana Bala Lakshmanan

Material Science and Engineering Theses - Archive

The main goal of this research is to use Gold/ Copper Sulphide (Au/ CuS) and Gold nanoparticles (AuNPs) for improving the therapeutic effects in the treatment of cancer. One of the biggest successes in photothermal therapy is the use of AuNPs which however has its own drawbacks i.e. it is expensive and that the NIR absorption of Au nanostructures is from surface plasmon resonance which is dependent on the dielectric constant of the surrounding matrix. Thus, the plasmon absorption maxima would shift for in-vivo observations compared to in-vitro. Alternatively, Copper Sulphide (CuS) nanoparticles, developed recently, have also been used for …

Pulsatile Protein Release From A Thermoresponsive Hydrogel: Effect Of Device Architecture, Nanoparticle And Polymer Concentration Using Factorial Analyses, Shruti Gandhi

Material Science and Engineering Theses - Archive

A pulsatile thermo-responsive drug delivery device for wound healing applications was developed in this study and its drug release during 24 hours of thermal cycling was characterized. The device consisted of a temperature sensitive hydrogel of poly (N-isopropyl acrylamide-co-acrylamide) (PNIPAM-AAm) nanoparticles (LCST: 39-40°C) embedded in a poly (ethylene glycol) diacrylate (PEGDA) matrix inside a device made of poly (methyl methacrylate). The device had four different orifice geometries all with the same surface area of opening (5 mm2): slit, cross, circle and four-circle. Bovine serum albumin (BSA) was loaded onto the hydrogel as the model protein. The effect of the orifice …

The Analysis And Testing Of The Quaife Torque-Biasing Differential, John W.H. Trout

Mechanical and Aerospace Engineering Theses - Archive

The purpose of this thesis is to analyze and test the Quaife torque biasing differential. The differential was modeled mathematically and equations were formulated. Experiments were then performed on a Formula SAE car to see how the output torque of each axle would react to modified preload torques. The results of these tests were then compared with the mathematical models. Overall, it was found that the there are two equations that govern the differential: one for traction and one for slip, and that the derived model correlates well with the experimental results.

Parametric And Performance Analysis Of A Hybrid Pulse Detonation / Turbofan Engine, Sivarai Amith Kumar

Mechanical and Aerospace Engineering Theses - Archive

The performance of a hybrid pulse detonation engine (PDE), with the PDE tubes installed in the bypass duct of a turbofan engine is investigated in this study. Performance parameters for the duct burning PDE engine are compared with a baseline turbofan engine. The PDE analysis is based on an updated numerical analysis by Endo-Fujiwara, whereas the turbofan calculations are based on Mattingly's gas turbine model. The calculations were done with MATLAB 2010 as a platform. A mixer analysis was performed for the hybrid engine concept. In the duct burning PDE, the PDE exhaust was mixed with the turbine exhaust prior …

Analytical Parametric Cycle Analysis Of Continuous Rotating Detonation Ejector-Augmented Rocket Engine, Huan V. Cao

Mechanical and Aerospace Engineering Theses - Archive

An analytical parametric cycle analysis model for the continuous rotating detonation wave ejector-augmented rocket was developed to estimate and evaluate the maximum potential performance that the continuous rotating detonation wave rocket (CRDWR) itself can provide in an ejector ramjet as well as the two-stage rocket for low earth orbit (LEO). This was done by integrating Bykovskii's model for CRDWR with Heiser & Pratt's modified ejector ramjet and their transatmospheric performance model. The performance results of this unique engine in comparison to a regular rocket counterpart were evaluated primarily in terms of specific thrust and specific impulse with respect to flight …

Issues On Finite Element Modeling Of Laminated Composite Structures, Farhan Alamgir

Mechanical and Aerospace Engineering Theses - Archive

Composite structures have been used widely in aviation industries and civil construction field because of their high specific stiffness, high specific strength and directional dependent properties. When using finite element method to analyze these structures, special attention of modeling is required. This thesis addresses the effect of layer stresses and displacements of a laminate under loading due to element meshing, boundary constraints and material properties used in modeling of composite structures. This study also includes the investigation of the magnitude and location of the layer peak stresses on modeling the laminate with a hole. It is concluded that special characteristics …

Development Of Ultra-High Temperature Material Characterization Capabilities Using Digital Image Correlation Analysis, Julia Elaine Cline

Mechanical and Aerospace Engineering Theses - Archive

Ultra-high temperature deformation measurements are required to characterize the thermo-mechanical response of material systems for thermal protection systems for aerospace applications. The use of conventional surface-contacting strain measurement techniques is not practical in elevated temperature conditions. Technological advancements in digital imaging provide impetus to measure full-field displacement and determine strain fields with sub-pixel accuracy by image processing. In this work, an Instron electromechanical axial testing machine with a custom-designed high temperature gripping mechanism is used to apply quasi-static tensile loads to graphite specimens heated to 2000°F (1093?C). Specimen heating via Joule effect is achieved and maintained with a custom-designed temperature …

Plate Analysis With Different Geometries And Arbitrary Boundary Conditions, Ashwin Balasubramanian

Mechanical and Aerospace Engineering Theses - Archive

This thesis work deals with the study of plates with various geometries and different boundary conditions. The method of study is carried out mainly using the Galerkin method combined with the help of the symbolic algebraic software, Mathematica. In this thesis, flat plates with rectangular and triangular geometries are subjected to uniform load acting normal to their surfaces. The lateral deflection of the plates is expressed in a series of polynomials which satisfy the homogenous boundary conditions. Mathematica is used in handling the algebraic operations to solve for the coefficients and generating the trial functions. The maximum deflection of the …

Consideration Of Compressibility Effects For Applied-Back-Pressure Dynamic Well Control Response To A Gas Kick In Managed Pressure Drilling Operations, William Alexander Bacon

Mechanical and Aerospace Engineering Theses - Archive

Managed Pressure Drilling (MPD) operations offer the ability to control a relatively small gas kick dynamically, without shutting in the well using blowout preventers. One currently employed method of dynamic well control uses applied-back-pressure to force flow exiting the wellbore to equal flow entering the drill-pipe, which is taken as an indication that the influx has stopped. However, for flow out equals flow in to imply influx cessation, the assumption of incompressibility of fluid in the wellbore is necessary. When fluid compressibility is appreciable, solely ensuring flow rate continuity does not necessarily imply influx cessation. The period of "dynamic well …

Numerical Analysis Of The Interaction Between A Detonation Wave And Compressible Homogeneous Isotropic Turbulence, Monika Chauhan

Mechanical and Aerospace Engineering Theses - Archive

A numerical study was performed to investigate the effect of preshock turbulence on the detonation wave properties. A direct numerical simulation was performed on the chemically reactive Navier-Stokes equations using a Runge-Kutta scheme and a fifth-order WENO spatial discretization. We performed a direct numerical simulation (DNS) which belongs to the domain of Computational Fluid Dynamics (CFD), of the fluid mechanics equations in three dimensions to determine the fine scale evolution. A simple one-step chemical kinetics model was used in the study.The main objective of the research is to examine the behavior of the turbulence when subjected to a strong shock …

Airfoil-Shaped Extension-Twist-Coupled Composite Star-Beams For Rotor Blade Tip Applications, Sthanu Mahadev

Mechanical and Aerospace Engineering Theses - Archive

Rotorcraft blade tips provide the most effective region for aerodynamic control. Rotor blade airloads are proportional to dynamic pressure and as a consequence are typically the highest in the distal blade tip region. Therefore, blade control using aerodynamic forces and moments is most effectively accomplished over the distal region of the blade. Composite materials represent the preferred material option for modern rotor blade design, especially in the field of rotorcraft and wind energy, due to superior strength-to-weight ratio, fatigue resistance and their ability to be easily tailored to incorporate different coupling (bend-twist, extension-twist, etc.) among elastic modes of deformation within …

Design Optimization Using Augmented Lagrangian Particle Swarm Optimization, Chethan Shivappa Thenehalli

Mechanical and Aerospace Engineering Theses - Archive

Engineering optimization problems normally include multiple, non-trivial, non-linear constraints. Traditionally gradient based optimization methods were used to solve these types of problems because of their high computational efficiency. But they generally require continuity of the optimization problem and the computation of derivatives and tend to get trapped in local minima. Hence non gradient based, evolutionary algorithms (EA) which are based on heuristic and stochastic nature and do not require continuity of the design space of the optimization problem and increase the probability to find a global optimal solution, therefore are becoming a popular choice in recent years. This work uses …

Stress Analysis For A Three Phase Plate With A Concentric Circular Inclusion By Deriving An Airy Stress Function, Abhishek Kunchala

Mechanical and Aerospace Engineering Theses - Archive

This thesis derives the Airy stress function for a three phase plate that consists of two concentric circular inclusions and a matrix phase. It incorporates the elastic property of each phase as well as the geometry of the inclusions. An Airy stress function has been derived that satisfies the continuity conditions of the displacement and traction across the phase interface precisely. The obtained results are new and could not have been possible without a computer algebra system (Mathematica).

Finite Element Based Stability Constrained Weight Minimization Of Sandwich Composite Ducts For Airship Applications, Urmi B. Khode

Mechanical and Aerospace Engineering Theses - Archive

High Altitude Long Endurance (HALE) airships are platform of interest due to their persistent observation and persistent communication capabilities. A novel HALE airship design configuration incorporates a composite sandwich propulsive hull duct between the front and the back of the hull for significant drag reduction via blown wake effects. The sandwich composite shell duct is subjected to hull pressure on its outer walls and flow suction on its inner walls which result in in-plane wall compressive stress, which may cause duct buckling. An approach based upon finite element stability analysis combined with a ply layup and foam thickness determination weight …