Engineering Commons^™

Low-Thrust Control Of A Lunar Orbiter, Nathan Harl

Masters Theses

"This thesis presents a method for maintaining a long-term lunar Sun-synchronous orbit using continuous low-thrust hardware. The control method is developed using optimal control theory, which involves controlling a system through the minimization of a desired cost function"--Abstract, page iii.

Refrigerant-Based Propulsion System For Small Spacecraft, Carl Reiner Seubert

Masters Theses

"The MR SAT spacecraft under development at UMR requires a propulsion system that can be utilized to perform orbital maneuvers and three-axis attitude control to complete its mission objective of conducting spacecraft formation flight. This thesis documents the research, analysis design and development of the cold gas propulsion system that was integrated on the MR SAT spacecraft"--Abstract, page iii.

Magnetohydrodynamic Power Generation In A Scramjet Using A Post Combustor Generator, Nathan Lee Mundis

Masters Theses

"A scramjet with a post combustor MHD generator is examined. A quasi-one-dimensional model is developed to calculate the flow path from tip to tail. The model includes losses due to combustion irreversibility, incomplete combustion, chemically reacting flow, friction, MHD losses, and nozzle plume modeling. Flight Mach number, magnetic field strength, gas conductivity, MHD load factor, and MHD generator expansion angle are all varied in order to assess their effects on MHD power generated and thrust lost in the engine. The trends produced through the above variations are summarized in a set of model-fit equations. It is concluded that a post …

A Guide To The Establishment Of A University Satellite Program, Abbie Marie Stewart

Masters Theses

"The UMR SAT team was formed at the University of Missouri-Rolla to design and build microsatellites. The team competed against ten other universities in the Nanosat 4 competition hosted by the Air Force Office of Scientific Research, the Air Force Research Laboratory, and the American Institute of Aeronautics and Astronautics. This document, written by the Chief Engineer, is a description of the process used by the UMR SAT team to develop a successful satellite program. Included in the document are methods based on systems engineering for developing a mission, a discussion of team organization and recruitment, and lessons learned during …

Configuration, Manufacture, Assembly, And Integration Of A University Microsatellite, Lori Ann Ziegler

Masters Theses

"The Space Systems Engineering Team at the University of Missouri-Rolla (UMR), in conjunction with a number of Air Force, NASA, and industry mentors, is working toward the design, development, and launch of its first satellite, UMR SAT (University of Missouri-Rolla Satellite). This thesis documents the design of the UMR SAT satellites, specifically focusing attention on the layout of all components, component boxes designed for containment and protection from electromagnetic interference and the attachment of components inside the boxes and the boxes to the structure. This thesis also discusses the development of UMR SAT with challenges faced in manufacturing and prototyping …

Controls Algorithm For A Satellite Using Earth's Magnetic Field: Orbit Maneuvers And Attitude Positioning, Karthik Ganesh

Electronic Theses and Dissertations

This document describes the design, analysis of Orbit Maneuvers and Attitude Control for NanoSat class satellites, which uses an electro-magnetic force controller which was proposed by the Florida Space Institute (FSI). Orbit Maneuvering and the Attitude Control System (ACS) play a very important role for the success of this mission, as that can allow making the satellite go to the desired orbit as well do the sun pointing of the solar arrays with su¢ cient accuracy to achieve desired power levels. The primary mission would be to attain attitude stabilization using the torque from the coils. This is also used …

Near Optimal Output-Feedback Control Of Nonlinear Discrete-Time Systems In Nonstrict Feedback Form With Application To Engines, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement-learning based output-adaptive neural network (NN) controller, also referred as the adaptive-critic NN controller, is developed to track a desired trajectory for a class of complex nonlinear discrete-time systems in the presence of bounded and unknown disturbances. The controller includes an observer for estimating states and the outputs, critic, and two action NNs for generating virtual, and actual control inputs. The critic approximates certain strategic utility function and the action NNs are used to minimize both the strategic utility function and their outputs. All NN weights adapt online towards minimization of a performance index, utilizing gradient-descent based rule. …

Addressing Student Retention In Engineering And Engineering Technology Through The Use Of A Multidisciplinary Freshman Course, Anthony Dean, Bonita Anthony, Linda Vahala

Engineering Technology Faculty Publications

The Engineering Fundamentals Division of the Batten College of Engineering and Technology (BCET) at Old Dominion University administers a freshman engineering course sequence, along with four engineering departments (Mechanical Engineering, Civil and Environmental Engineering, Aerospace Engineering, and Electrical and Computer Engineering) and the Department of Engineering Technology (which offers degrees in Mechanical Engineering Technology, Civil Engineering Technology and Electrical Engineering Technology). The two course sequence, Exploring Engineering and Technology I and II, involve the five departments in teaching at least one five week module in each of the two courses. Each department generally involves the students in a basic design …

Modeling Redox-Based Magnetohydrodynamics In Three-Dimensional Microfluidic Channels, Hussameddine S. Kabbani, Aihua Wang, Xiaobing Luo, Shizhi Qian

Mechanical Engineering Faculty Research

RedOx-based magnetohydrodynamic MHD[1] flows in three-dimensional microfluidic channels are investigated theoretically with a coupled mathematical model consisting of the Nernst-Planck equations for the concentrations of ionic species, the local electroneutrality condition for the electric potential, and the Navier-Stokes equations for the flow field. A potential difference is externally applied across two planar electrodes positioned along the opposing walls of a microchannel that is filled with a dilute RedOx electrolyte solution, and a Faradaic current transmitted through the solution results. The entire device is positioned under a magnetic field which can be provided by either a permanent magnet or an electromagnet. …

Manufacturing Of Glass Ribbon Reinforced Transparent Composites Using The Autoclave Process, Josef Patrick Seale

Masters Theses

"Clear transparent panels have many applications ranging from windows on an aircraft to protective safety guards on industrial equipment. Glass ribbon reinforced transparent composites are light weight, load bearing and have a high impact resistance.

A transparent composite is based on the concept of matching the refractive index of the glass ribbon with that of a resin system. It is not necessary that the resin refractive index match the glass refractive index before the cure cycle, only that the refractive indexes match after curing.

Transparent composites have a high impact resistance that would be mechanically ideal for aircraft windows and …

Novel Concepts For Enhanced Nuclear Thermal Propulsion Using Flow Area Tailoring And A Grooved-Ring Core Design, Julien Michel Apeloig

Theses and Dissertations

The most likely candidate for human missions to Mars and beyond will be spacecraft using Nuclear Thermal Propulsion (NTP). NTP provides for high thrust-to-weight ratio and significantly improved specific impulse over even the best chemical rockets. The improved specific impulse reduces required trip times, thereby minimizing the exposure time of the crew to space radiation. Using the PHOEBUS 2A 5 GW reactor, developed in the 1960’s with a thrust of 1,113 N and a specific impulse of 820 s, as a basis for comparison this thesis focuses on efforts to improve the specific impulse and reactor longevity. Hydrogen is the …

Reconstructing Spectral Scenes Using Statistical Estimation To Enhance Space Situational Awareness, Travis F. Blake

Theses and Dissertations

A new sensor, the Advanced Electro-Optical System (AEOS) Spectral Imaging Sensor (ASIS) has been developed at the Maui Space Surveillance Complex (MSSC). ASIS is capable of collecting resolved imagery of space objects in 10's-100's of spectral bands while using an adaptive optics system. However, the stringent requirements of collecting ground-based images requires a sensor that induces spectral blurring. Post-processing algorithms to remove this blurring are required to fully exploit these spectral images. This research focuses on developing the reconstruction algorithms, based on proven estimation theories, required to spectrally deblur the images collected from ASIS. Additionally, the research will expand the …

Trajectory Model Validation Using Newly Developed Altitude-Controlled Balloons During The International Consortium For Atmospheric Research On Transport And Transformations 2004 Campaign, Emily E. Riddle, Paul B. Voss, Andreas Stohl, Daniel Holcomb, Darren Maczka, K. Washburn, Robert W. Talbot

Engineering: Faculty Publications

During the summer of 2004, five altitude-controlled tracking balloons were flown as part of the International Consortium for Atmospheric Research on Transport and Transformations (ICARTT) campaign. These Controlled Meteorological (CMET) balloons, newly developed at the University of Massachusetts, are notable for their light weight (∼1 kg mass), efficient altitude control, case of launch, long-duration flight capability, and ability to perform repeated quasi-Lagrangian soundings. The balloons were embedded in urban plumes from New York and Boston which they tracked over New England, eastern Canada, and the Atlantic Ocean while maintaining a nearly constant altitude. The flights ranged from 10 to 111 …

Branch Detonation Of A Pulse Detonation Engine With Flash Vaporized Jp-8, John David Slack

Theses and Dissertations

Pulse Detonation Engines (PDE) operating on liquid hydrocarbon fuels are limited to operating frequencies of 35 Hz due to long ignition times from a low energy ignition sources. This study shows ignition time of JP-8 can be nearly eliminated by igniting a thrust tube using a secondary detonation. A counter flow heat exchanger attached to a thrust tube utilized waste heat from the detonation process to heat JP-8 to supercritical conditions. The fuel flash vaporized when injected into the air stream of the engine. A detonation was produced by a spark in a 5 cm diameter, 1.37 m long tube. …

Multi-Sensor Fusion Based Control For Autonomous Operations: Rendezvous And Docking Of Spacecraft, Jonathan Bryan Mcdonald

Mechanical and Aerospace Engineering Theses - Archive

The project considers the problem of motion synchronization of free flying robotic spacecraft and serviceable floating objects in space. The synchronization maneuvers are based on sample and hold nonlinear translational and attitude control laws. GPS pseudorange signals and a vision based sensor unit are modeled to give position measurements; position and velocity estimates are extracted from the measurements based on Extended Kalman Filter models. A sensor data fusion algorithm in the form of a Federated Extended Kalman Filter is implemented that blends the estimates of the individual filters into a global estimate. Nonlinear simulations where a Pursuer spacecraft attempted to …

Enhancement Of Pool Boiling Heat Transfer Using Thermally-Conductive Microporous Coating Techniques, Joo Han Kim

Mechanical and Aerospace Engineering Dissertations - Archive

The present research is an experimental study of the enhancement of boiling heat transfer using microporous coating techniques. The current research is divided into four major phases. During the first phase, the effects of different metal particle sizes in the coating compound for thermally non-conductive microporous coating on pool boiling performance of refrigerants and water are investigated. The test surfaces, solid copper blocks with 1-cm² base, were tested at atmospheric pressure in saturated FC-72, R-123, and water. Results showed that the surface treatment by non-conductive microporous coating significantly enhanced both nucleate boiling and critical heat flux of all three refrigerants. …

Flexible Microfluidic Circuit With Embedded In-Plane Valve, Srikar C. Paruchuri

Mechanical and Aerospace Engineering Theses - Archive

Recent developments in Microfluidic systems have demonstrated many potential applications related to biology, chemistry and medical sciences. Fluidic manipulation with precise volume control is a basic function in these systems, and microvalves play an important role in control and delivery of the fluid sample. One of the key issues in such valve design is to make large membrane deflections compared to the channel dimension. This thesis reports a flexible microfluidic chip with embedded in-plane valves for fluid manipulation. Silicone elastomer (Polydimethylsiloxane - PDMS) is one of the most suitable materials to fabricate microvalve membranes, because of its low Young's modulus, …

Computer-Aided Patient Specific Treatment Planning Of Cryosurgery For Breast Cancer, Junkyu Jung

Mechanical and Aerospace Engineering Theses - Archive

Cryosurgery, which is to destroy tumors by use of localized freezing, is an emerging treatment modality for breast cancer as the size of detectable tumor becomes smaller due to more frequent use of various diagnostic imaging including MRI, CT and mammogram. Although general surgical guideline has been developed and its effectiveness has been demonstrated, cryosurgical protocol should be adjusted for a given patient to accommodate patient-specific variations including tumor size, location and geometry of patient's breast. In this study, a computerized treatment planning tool was developed to aid surgeons to determine surgical parameters considering patient specific diagnostic information. This tool …

Freezing-Induced Microstructural Changes Of Collagen Scaffolds, Jeffrey David Miller

Mechanical and Aerospace Engineering Theses - Archive

Understanding the effects of freezing on the functional properties of tissues is critical to cryopreservation of native and artificial tissues, and prognosis after cryotherapies. Although investigations have been performed to correlate macroscopic properties such as mechanical properties with freezing parameters, the effects are typically tissue-type dependent and no physical understanding is available to explain these effects. Since the mechanical and optical properties of a tissue are based on the characteristics of its extracellular matrix (ECM), understanding and quantifying these changes could assist in predicting the response a tissue will have to freezing under different circumstances. In this study, the microstructural …

Coupling Of Fluid & Solid Thermal Models To Correct Heat Flux Measurements Taken On Launch Vehicles, Danielle M. Ford

Master's Theses - Daytona Beach

Knowledge of aerothermally induced convective heat transfer and plume induced radiative heat transfer loads is essential to the design of thermal protection systems (TPS) for launch vehicles. These loads are measured via the cylindrical heat flux gauges that are flush mounted with the outer surface of a launch vehicle and are exposed to the in-flight external thermal and velocity boundary layers as well as thermal radiation. Typically, Schmidt-Boelter gauges measure the incident heat flux based on the one-Dimensional Fourier's law. This instrumentation, when surrounded by low-conductivity insulation, has an exposed surface temperature significantly lower than the insulation. A substantial disturbance …

Neural Network Burst Pressure Prediction In Composite Overwrapped Pressure Vessels From Acoustic Emission Data, Seth-Andrew T. Dion

Master's Theses - Daytona Beach

Composites have grown in importance in the aerospace industry where high specific strength is a priority. Weight reduction in space vehicles is critical because of the exorbitant cost associated with placing objects into space. Major weight savings have been obtained by switching from all metal pressure vessels to composite overwrapped pressure vessels (COPVs). Due to the nature of composites, current nondestructive analysis procedures for COPVs are not adequate for assessing structural integrity. As such, new methods must be developed. Presented herein is one such method.

A method for burst pressure prediction using parametric filtering of acoustic emission (AE) data along …

Optimization Of The Tool Path In A Robotic Environment, Mukund Venkatachari Narasimhan

Mechanical and Aerospace Engineering Dissertations - Archive

The rising costs and demand coupled with shrinking energy generating resources has triggered the need for optimum use of energy resources, minimizing the overhead costs and maximizing the profits. Robots have been long touted as a fit replacement of human labor force in manufacturing sectors. Slowly there is increased presence of robots in automobile and electronic industries. Typically they are used for welding, painting, ironing, assembly, pick and place, inspection, and testing. Mass production, fulfilling the ever increasing demand, can be accomplished by robots because of their precision, speed of operation and high endurance capabilities. This dissertation comprises of two …

Finite Element Modeling Of Carbon Nanotube Reinforced Polymer Composites And Evaluating Its Thermal Conductivities, Raghuram Basavanahalli

Mechanical and Aerospace Engineering Theses - Archive

High thermal conductivity of carbon nanotubes has motivated us to study and understand the thermal mechanisms in nanocomposites. Though several theoretical models predict a high thermal conductivity for CNT reinforced polymer composites, the experimental validation are not so encouraging. A finite element model of MWNT reinforced nanocomposite is developed based on continuum mechanics approach. The finite element model is a representative volume element (RVE) with single MWNT inclusion. The inclusion is modeled based on the continuum model of MWNT as effective solid fiber [22].The interface resistance between the nanotube and the matrix material is modeled using thermal contact elements. The …

Structural Analysis Of Fiber Reinforced Composite Materials, Cesar Augusto Rojas

Mechanical and Aerospace Engineering Theses - Archive

A study of fiber reinforced composite structures is conducted .This study includes laminate analysis, analysis of laminated composite beams and parametric study of composite beams. Finite element analysis for each beam model is conducted to verify the results obtained by analytical model. The analysis of the laminated beams in this study covers: 1. beam with a solid rectangular cross-section subjected to a transverse load 2. beam with a I-section under bending 3. beam with a squared tubular section under bending 4. beam with truss section under bending One of the principal purposes of this thesis is to create a user …

Investigation Of Soft Failure Of Small Form Factor Hdd Under Forced Vibration, K. T. Chua, A. Yudhanto, E. H. Ong, J. Q. Mou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

As small form factor hard disk drives (HDD) are increasingly used in portable consumer devices, the performance of the HDD in daily activity is highly concerned. In this paper, the soft failure of the hard disk drive under forced vibration is investigated. To investigate the cause of the soft failure, experimental frequency analysis was conducted. Modal analysis of HDD was completed by experiment and verified by FEM simulations and the result was compared to the frequency response result. Studies show that the vibration modes of head suspension assembly (HSA) and disk platter at higher resonant frequencies do not directly relate …

Vacuum Chamber Construction And Contamination Study Of A Micro Pulsed Plasma Thruster, Jacob H. Debevec

Theses and Dissertations

The micro pulsed plasma thruster (micro-PPT) is a simple and versatile electric thruster capable of performing multiple missions, from precise attitude control on standard satellites to primary propulsion for nanosatellites. In order to fill this role as both industry and government move toward utilizing smaller satellites, micro-PPTs first need to be thoroughly tested on the ground. This study examines the deposition profile and rate of particle emission from the thruster so that satellite designers understand any potential contamination issues with sensitive instruments and solar panels. Employing a newly assembled vacuum chamber system, four tests were completed with the micro-PPTs, and …

Integrated Conceptual Design Of Joined-Wing Sensor Craft Using Response Surface Models, Josh E. Dittmar

Theses and Dissertations

A multidisciplinary conceptual design and analysis of Boeing's joined-wing SensorCraft has been conducted. This analysis was completed using geometrical optimization, aerodynamic analyses, and response surface methodology on a composite structural model. Phoenix Integration's Model Center was used to integrate the sizing and analysis codes found in Raymer's text, "Aircraft Design: A Conceptual Approach" as well as those from the NASA derived conceptual design tool AirCraft Synthesis (ACSYNT), and a modified Boeing Finite Element Model (FEM). This research demonstrated the utility of integrated low-order models for fast and inexpensive conceptual modeling of unconventional aircraft designs.

Design And Optimization Of Heat Spreaders And Selection Of Fan In Laptop, Kranthi Kumar Manne Sambaiah

Mechanical and Aerospace Engineering Theses - Archive

Technical advancements lead to the need for faster processors and reduced sizes in electronic systems. The urge for faster and compact systems leads to two major problems. Firstly over heating of chips which degrade the chip performance and secondly formation of heat spots on the surface which makes the user uncomfortable. Thermal management engineers, as a result have a major challenge in improving the cooling systems. In this research project simulation using the thermal modeling tool selected is Icepak. The prototype model of the laptop is designed, boundary conditions are applied and analysis is done. The results so obtained in …

Investigation Of Knock In Gaseous Fuels In The Presence Of Diluents, Roshan Ashok Rodrigues

Masters Theses

Recent energy security and environmental concerns have prompted growing interest into utilization of alternative fuels such as, natural gas and landfill gas. These gaseous fuels contain significant amount of diluents in the fuel composition, such as carbon dioxide, nitrogen, water vapor and other trace gases, which vary by geographical location. Successful engine operation is limited by a phenomenon called "knock", which occurs due to auto-ignition of the end gas ahead of the flame front, and therefore, needs to be investigated with the utilization of these gaseous fuels.

The present contribution discusses the experimental set-up, procedure and results of the investigation …

An Exploration Of Several Structural Measurement Techniques For Usage With Functionally Graded Materials, Robert A. Reuter

Theses and Dissertations

Titanium / titanium boride functionally graded 6"x 1"x1" beams were subjected to a four-point beam test in order to critique the value of several measurement techniques. Also, finite element analysis results were compared with experimental values and general observations about the experiment were recorded. Uniform 85% TiB /15% Ti and uniform commercially pure titanium specimens were also subjected to the same loading conditions as a control. Techniques used include digital image correlation, fiber optic strain gauging, strain gauging, and differential infrared thermography techniques. The strain data results were compared with one another and to linear finite element models. It was …