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Analysis and Design of the Mechanical Systems Onboard a Microsatellite in Low-Earth Orbit: An Assessment Study: Author: Solomon, Dylan Raymond; Date: 2006-05-15; Program: Mechanical Engineering; Abstract: A study of the Mechanical systems contributing to the design and performance of a picosatellite's mission in low-Earth orbit (LEO) was performed through design and analysis. The unique architecture of this satellite stems from a form factor established by the internationally recognized CubeSat Program. This CubeSat-Plus architecture limits the satellite's size to be no larger than a 10 x 10 x 15 cm cube with an overall mass not exceeding 2 kg. This satellite would then be launch into LEO and conduct on-orbit GPS measurements while remaining tethered to the second stage booster of a Boeing Delt...; Download File | View full details

Analytical and Experimental Study of Radiation-Recrystallized Near-Surface Facets in Snow: Author: Morstad, Blake Walden; Date: 2004-08-15; Program: Mechanical Engineering; Abstract: A study on the formation of radiation recrystallized near-surface facets in snow was performed experimentally in an environmental chamber. This recrystallization occurs when surface snow metamorphoses into faceted crystals that result from absorbed solar radiation coupled with cooling effects from longwave and turbulent fluxes. The environmental chamber utilized a metal-halide lamp to mimic solar radiation, which penetrates the snow adding thermal energy at depth. In addition, the ceiling was cooled to simulate a cold sky, thus inducing a net longwave radiation loss at the snow surface. Turbul...; Download File | View full details

Application of Energy Methods to Modeling Failures in Composite Materials and Structures: Author: Ritter, William Joseph; Date: 2004-08-15; Program: Mechanical Engineering; Abstract: Characterizing the Mechanical properties of composite materials is difficult and expensive. There is a legacy for the scale up from basic materials testing to final structures in composites. Each material architecture and manufacturing technique potentially represents a different Mechanical response in a structure. Hence, as new composite material forms and manufacturing techniques become available, a need exists to streamline the characterization process. In this study, a new methodology for characterization of composite materials and structures is presented. It has its roots in fracture mech...; Download File | View full details

Effects of Manufacturing Conditions, Stresses, Temperature and Humidity on the Performance of an Innovative Fractional Order Control Device: Author: Kulkarni, Nachiket Ashok; Date: 2005-12-15; Program: Mechanical Engineering; Abstract: An innovative fractional order control device (Fractor) has been developed. The principal characteristic of the Fractor is a non-integer order power law relationship between the impedance and frequency. The exponent or the order in this power law is the Constant Phase Element (CPE). Warburg impedance is the ideal goal for the optimal performance of the Fractor which is intended for applications in feedback control systems. The Fractor is based on a specially developed material system which involves a synthesized polymer gel interfaced with metal electrodes. The roughness of the electrode is in...; Download File | View full details

Design and Evaluation of Compact Heat Exchangers for Hybrid Fuel Cell and Gas Turbine Systems: Author: Lindstrom, Joel David; Date: 2005-05-15; Program: Mechanical Engineering; Abstract: Hybridized Carbonate and Solid Oxide fuel cell power plants are currently under investigation to fulfill demands for high efficiency and low emissions. Selection and design of high performance heat exchangers are essential for such applications. In this work, various compact heat exchanger (CHEX) technologies pertinent to gas-gas recuperative duties are presented. The CHEX types considered include brazed plate-fin, fin-tube, microchannel, primary surface and spiral. Based on a comparative rating procedure, two CHEX designs namely, plate-fin and microchannel were chosen for further review. Plai...; Download File | View full details

Field Instrumentation and Live Load Testing to Evaluate Behaviors of Three Reinforced Concrete Bridge Decks: Author: Smolenski, Peter James; Date: 2004-08-15; Program: Mechanical Engineering; Abstract: The deterioration of reinforced concrete bridges in Montana has prompted the Montana Department of Transportation (MDT) to investigate alternative bridge deck designs which minimize concrete cracking and subsequent steel corrosion. Construction was completed during the summer of 2003 on three new bridges near Saco, Montana that afford an unusually good opportunity to investigate the performance of different bridge decks. Notably, the bridges are in close proximity, and are of the same geometric design. The only differences between the bridges is the deck construction: one deck has a convention...; Download File | View full details

Robust copper braze for hermetic sealing of solid oxide fuel cells: Author: Ator, Danielle Elizabeth; Date: 2008-08-15; Program: Mechanical Engineering; Abstract: Solid oxide fuel cells (SOFCs) are becoming of increasing interest as a primary power source in today's industrial market. The voltage of a single cell under load is approximately 0.7 volts necessitating the use of many cells in series to generate useful electrical potentials, which gives rise to the SOFC stack. One of the key technical challenges in improving the long term performance and reliability of stacks is in the effective sealing of stack interfaces, particularly in planar stacks for which a hot seal (700-900°C) is required. SOFC stack seals must be: resistant to oxidation...; Download File | View full details

Feasibility in developing smart structures for use in wind turbine blades: Author: Blockey, James Craig; Date: 2008-08-15; Program: Mechanical Engineering; Abstract: Recently the use of wind as an alternative energy source has developed quickly. The length of the blades is a leading factor in the power output of a wind turbine and as a result, blade length has grown at a similar pace to the growth of the industry. The rapid expansion in use and size of wind turbines is not without its problems, though. As the industry has changed and grown, the overall design of the blades has remained relatively stagnant. This is evident in two primary areas, power control and health monitoring. Power control mechanisms are generally unchanged, utilizing either pitch cont...; Download File | View full details

Resonant Ultrasound Spectroscopy in Complex Sample Geometry: Author: Fig, Matthew Kenneth; Date: 2005-12-15; Program: Mechanical Engineering; Abstract: Resonant Ultrasound Spectroscopy (RUS) is the study of the Mechanical resonances, or normal modes, of elastic bodies to infer material properties such as the elasticity matrix. This powerful technique is based on two physical facts, the first of which is that the resonant response of an elastic object depends on several parameters intrinsic to the object, such as the object's shape, density, elastic constants, and crystallographic orientation. The second is that using these parameters, the resonant spectrum of an object can be calculated. This method has widely been applied to rectangular para...; Download File | View full details

Simulation and Testing of Resin Infusion Manufacturing Processes for Large Composite Structures: Author: Mastbergen, Daniel Blair; Date: 2004-08-15; Program: Mechanical Engineering; Abstract: The use of composite materials in large primary structures such as wind turbine blades and boat hulls has dramatically increased in recent years. As these structures get larger, new manufacturing processes are required to make them possible. Larger parts also require more expensive tooling, and a higher cost for scrapped parts. This may prohibit the trial and error approach that has been used for many years. The need for accurate process modeling in the design of tooling is becoming essential. Unfortunately, as the processes become more complex so do the models. Although there are several pote...; Download File | View full details

Synthesis and Characterization of Hydrogen Separation Membranes: Author: Lakshminarayanan, Karthikeyan; Date: 2005-05-15; Program: Mechanical Engineering; Abstract: Hydrogen can be obtained from purification of water gas by ceramic hydrogen separation membranes. These membranes need to be further improved to obtain reasonable production of hydrogen from water gas. Fuel cell materials and state of the art ceramic membranes were characterized by impedance spectroscopy and dielectric measurements. To block the ionic and electronic conductivity, blocking layers of MgO were used. The coating thickness was analyzed by RBS and SEM techniques. Dielectric measurements with blocking layers and impedance measurements without any blocking layers were made over a wide...; Download File | View full details

Ultrasonically Controlled Antibiotic Release from Hydrogel Coatings for Biofilm Prevention: Author: Norris, Patrick Michael; Date: 2004-12-15; Program: Mechanical Engineering; Abstract: Medical devices are routinely employed in healthcare settings since they provide clinicians with a means of administering nutrients, drawing blood samples and drug delivery. However, local and systemic infections are frequently associated with the use of medical devices and implants. In fact, implanted devices often provide a highly suitable surface for bacterial adhesion and colonization resulting in the formation of complex, differentiated and structured communities known as biofilms. Once a biofilm infection is established, conventional treatments frequently fail as bacteria in the form of ...; Download File | View full details

Use of Pultruded Carbon Fiber / Epoxy Inserts as Reinforcement in Composite Structures: Author: Bundy, Bryan Charles; Date: 2005-05-15; Program: Mechanical Engineering; Abstract: As polymer matrix composite based structures such as wind turbine blades get larger in span, the required stiffness is usually supplied by the increasing thickness. The fabrication of current composite thicknesses is expensive in terms of labor, Mechanical components and fabrication time. The problems are compounded for very long spans. Thermosetting resins are injected into these fiber pre-forms under very high pressures so the resin can completely encase the fibers before the resin hardens. These pressures can induce waviness into the fibers that significantly reduces the critical compressio...; Download File | View full details

A Validation Study of the Montana State University In-Plane Loader: Author: Collett, Aaron Bruce; Date: 2006-08-15; Program: Mechanical Engineering; Abstract: Characterizing a polymer composite material's response to loading beyond the elastic region is less well defined than it is for other structural materials such as metals. The Naval Research Laboratory has developed a method that uses dissipated energy as a metric to facilitate this characterization. The method relies on empirical data from material strength tests as well as finite element analysis data to make the prediction. A substantial amount of empirical data from different loading conditions is needed to characterize a material. This warrants a testing machine that can apply several load...; Download File | View full details

Static and Dynamic Behavior of Stress Coated Membranes: Author: Nandurkar, Kuldeep Pandurang; Date: 2006-08-15; Program: Mechanical Engineering; Abstract: Large space mirrors need to be made of ultra-lightweight materials (membranes) that have very low densities and high flexibility (compliance) for packaging. A coating application necessary for optical reflectivity may also impart to these ultra-lightweight materials a desired shape and to help maintain that shape in the harsh environment of space. When a coating is applied on the membrane substrate, stresses develop in the coating due to atomistic processes. These stresses are fundamental to the final shape of the substrate. Coatings applied to the substrate in order to maintain a particular s...; Download File | View full details

A Numerical Investigation of Thermal-Hydraulic Characteristics in Three Dimensional Plate and Wavy Fin-Tube Heat Exchangers for Laminar and Transitional Flow Regimes: Author: Panse, Satchit Pradip; Date: 2005-08-15; Program: Mechanical Engineering; Abstract: The plate fin-and-tube heat exchangers are used in wide variety of industrial applications, particularly in the heating, air-conditioning and refrigeration industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. The current study is focused on two fin configurations, the plain plate-fin and the wavy-fin. These two fin configurations are numerically investigated in both staggered and in-lined tube layouts. The present investigation ranges from laminar flow regime into the sub-critical or transitional flow regime. The suitability of the edd...; Download File | View full details

Progress and Challenges in Non-Linear Constitutive Modeling for Composite Material: Author: Booth, Eric Jason; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: In this paper is outlined a technique for determining the non-linear constitutive properties of an orthrotropic laminated material such as a fiber reinforced composite. The Characterization of Composites is difficult because of the anisotropic stiffness properties of the material and also because of the complex manner in which they accumulate internal damage and eventually fail. Presented here are techniques for determining the Mechanical properties of a material by solving what is known as the Inverse Problem. In such a problem, the response of a material system to an external stimulus is mea...; Download File | View full details

Efficient Finite Element Modeling Across Optical Length Scales: Author: Harwood, Jason Alan; Date: 2007-08-15; Program: Mechanical Engineering; Abstract: Optical engineers frequently rely on finite element analysis (FEA) to predict the thermal and Mechanical performance of an optic before it is produced. These analyses are usually performed by modeling a simplified version of the real structure to obtain the global deformations of the surface of the mirror. This method eliminates the ability to represent localized deformations and strain gradients, resulting from thermal and Mechanical loading, which may exceed the Mechanical limit of the materials or material interfaces in coated mirrors causing delamination or cracking. The goal of this study...; Download File | View full details

Fused Deposition Modeling with Localized Pre-Deposition Heating using Forced Air: Author: Partain, Seth Collins; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: Rapid prototyping (RP) systems have been used for several years to produce design prototypes without expensive tooling costs. As these systems have matured, there has been increasing interest in using them to produce actual end-use parts. Fused deposition modeling (FDM) is an RP technology that has been identified by many as having strong potential for this transition from rapid prototyping to rapid manufacturing, due primarily to its capability of using a wide array of high performance materials. FDM creates parts layer-by-layer, extruding semi-molten material "roads" through a comp...; Download File | View full details

Internal Damage Characterization for Composite Materials under Biaxial Loading Configuration: Author: Smith, Jay David; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: This thesis contains the results of a composite material database developed for fiber glass laminates using test data from the in-plane loader (IPL). The IPL is a unique multi-axial test machine developed at Montana State University. The research was completed with the aim to improve the reliability of composite materials, namely fiber glass for use in wind turbine blades. An energy method was used to characterize strain-induced damage in fiber glass coupons. The energy dissipated by internal failure mechanisms was employed as a metric of internal damage. Thus, by means of a deconvolution proc...; Download File | View full details

Modeling of In-Plane and Interlaminar Fatigue Behavior of Glass and Carbon Fiber Composite Materials: Author: Wilson, Timothy James; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: This thesis presents the results of a modeling study of the fatigue behavior of fiberglass and carbon fiber reinforced epoxy composite materials intended primarily for wind turbine blades. The modeling effort is based on recent experimental results for infused glass fiber laminates typical of current blades, and hybrid carbon prepreg laminates of potential interest for future blades. There are two focus areas: in-plane performance represented by stress-life (S-N) curves, and out-of-plane ply delamination at details including ply drops and joints, based on fracture mechanics. In-plane fatigue m...; Download File | View full details

Application of the Van Der Pauw Structure as a Piezoresistive Pressure Sensor - A Numerical Study: Author: Law, Jesse Townsend; Date: 2007-08-15; Program: Mechanical Engineering; Abstract: This research characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to MEMS pressure sensing. The sensor to be studied is a four-terminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. It is observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. With MEMS devices being used in applications which continually necessitate smaller size, characterizing the effect of size and orientation of a V...; Download File | View full details

Development of a Novel High Performance Electrolyte Supported Solid Oxide Fuel Cell: Author: Gentile, Paul Steven; Date: 2007-12-15; Program: Mechanical Engineering; Abstract: High power solid oxide fuel cell (SOFC) stacks are based on the planar design concept to yield high specific power densities. The key Engineering challenges to planar stack reliability and robust operation is attaining low resistance interconnection of individual cells in series and hermetic sealing of interconnects. While stack design and contact paste development is paramount to address this issue, the basic design of the fuel cell introduces limitations. State-of-the-art anode supported cells (ASC) yield high power densities due to low ASR thin electrolytes, however, the asymmetrical design...; Download File | View full details

An Inverse Approach to Coefficient of Thermal Expansion Optimization in Optical Structures: Author: Rassi, Erik Michael; Date: 2007-12-15; Program: Mechanical Engineering; Abstract: Optical component performance increasingly demands materials with tailored properties. Optical systems see applications where ambient conditions can drastically reduce performance. Optics used in space, for example, may undergo severe changes in temperature, which results in large thermally induced stresses and distortions. To minimize these thermal effects, it was desired to manipulate the coefficient of thermal expansion (CTE) within the material. However, wholesale reductions in CTE may not be optimum since synthetic manipulation of CTE often leads to undesirable effects on other material p...; Download File | View full details

Development of porous ceramics with graded columnar pore sturctures via freeze-tape casting: Author: McCrummen, John Drew; Date: 2008-05-15; Program: Mechanical Engineering; Abstract: Freeze-tape casting is a new processing technology that can generate continuous columnar-graded pore structures utilizing a wide variety of ceramic and/or metallic powders. The uni-directional solidification and subsequent freeze drying of yttria stabilized zirconia (YSZ) based aqueous cast tapes is being evaluated for various applications including fuel cells, filtration/separation membranes, and catalyst supports. The degree of pore divergence, pore packing, and pore orientation can be actively tailored by altering the solids loading, freezing rate, and tape pulling speed. The effects of sol...; Download File | View full details

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