Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Engineering, Mechanical Engineering (17)
- Applied sciences (11)
- Multi-user CAD (5)
- CFD (2)
- Computational fluid dynamics (2)
-
- Friction (2)
- Friction Stir Welding (2)
- Hand (2)
- Heterogeneous CAD (2)
- Inlet distortion (2)
- MPC (2)
- Model predictive control (2)
- Nanofibers (2)
- Numerical Modeling (2)
- SHM (2)
- Superhydrophobic (2)
- Superhydrophobic Surfaces (2)
- Thesis (2)
- Tribology (2)
- Turbomachinery (2)
- Undo (2)
- Water entry (2)
- Wetting (2)
- 3-Axis CNC Milling (1)
- 304L (1)
- 316L stainless steel (1)
- 3D printing (1)
- A DIC-Based Study (1)
- A Multiscale (1)
- ADS-B (1)
Articles 1 - 30 of 104
Full-Text Articles in Engineering
Design And Frequency Characterization Of Dual-Piezoresponsive Foam Sensors, Cory Nelson Newton
Design And Frequency Characterization Of Dual-Piezoresponsive Foam Sensors, Cory Nelson Newton
Theses and Dissertations
Multifunctional "self-sensing" materials at the frontiers of current research are generally designed to gather only a single type of information (such as quasi-static strain data). This project introduces a new sensor that is both multifunctional and dual-response, indicating its ability to not only perform in mechanical and sensing functions but also in its ability to sense multiple types of response. The proposed new class of sensing materials, comprised of nanocomposite polymer foams, exhibits measurable piezoresistive and quasi-piezoelectric phenomena in the form of change in resistance and voltage generation in response to deformation, respectively. An initial sampling of the envelope of …
On The Mechanical Response In Boundary Resisted Motion, Maliha Maisha Rahman
On The Mechanical Response In Boundary Resisted Motion, Maliha Maisha Rahman
Theses and Dissertations
In engineering and science literature, there seems to be a lack of consensus on a modeling framework clarifying how resistance to boundary motion affects mechanical performance. By mechanical performance, is implied the action of a force moving an object from one point to another that generates changes in position, velocity, acceleration and jerk. Apart from affecting a whole vehicle, critical power transmission components and subcomponents all rely on the mechanical responses that change due to an applied force. For example, the power needed to move an aircraft, an automobile, a ship, a submarine etc. will be reduced if resistance to …
Microstructure, Wetting Angle And Corrosion Of Aluminum-Silicon Alloys, Shvetashva Suri
Microstructure, Wetting Angle And Corrosion Of Aluminum-Silicon Alloys, Shvetashva Suri
Theses and Dissertations
In this study the effect of composition, surface roughness and water droplet size on contact angle and corrosion properties of cast Aluminum-Silicon alloys containing Si from 5% to 50% have been examined. The water contact angle was measured on a given sample using a goniometer. In addition, the effect of surface roughness and droplet size on contact angle has been measured for alloys at a fixed composition. The microstructures can be found in this report with sizes of primary and eutectic Silicon as well as inter-particle spacing between Silicon. Contact angle measurements are accompanied with a photographic validation of the …
Multivariate Calibration Of A Load Sensor For Dynamic And Static Freight Railcar Applications, Dylan Michael Blackwell
Multivariate Calibration Of A Load Sensor For Dynamic And Static Freight Railcar Applications, Dylan Michael Blackwell
Theses and Dissertations
Determination of the load carried by each bearing in a railcar system is crucial to the integrity of the railroad industry. With accurate load measurement, the process of filling a railcar with its specified cargo can be optimized to provide the maximum amount of cargo without exceeding the upper weight limits imposed by the Associations of American Railroads (AAR). An accurate load measurement will additionally make it possible to identify any load imbalance that occurs during periods of travel which result in having a detrimental effect on the health of the bearing. Previous work conducted with a strain-gauge load sensor …
Forcespinning®: An Alternative Method To Fabricate Metal Oxide/Carbon Composite Nanofiber Anodes For Li-Ion Batteries, Luis Zuniga
Forcespinning®: An Alternative Method To Fabricate Metal Oxide/Carbon Composite Nanofiber Anodes For Li-Ion Batteries, Luis Zuniga
Theses and Dissertations
Metals and their respective oxides have been highly regarded as next generation anode materials for lithium-ion batteries (LIBs). In this research work the electrochemical performance of Sn, SnO2, and TiO2. With the advantages of nanotechnology and the Forcespinning® method of fabricating micro and nanofibers, binder-free anodes are produced from metal or metal oxide/carbon composite microfibers. Through these microfibers the electrochemical performance of the above mentioned materials are significantly improved due to the increased surface area per volume providing a large number of reaction sites for the anode materials. Further performance enhancement was achieved by also modifying the fiber microstructure to …
Optimizing Border Security With Stochastic And Deterministic Strategies, Gabriel A. Rueda
Optimizing Border Security With Stochastic And Deterministic Strategies, Gabriel A. Rueda
Theses and Dissertations
International trade and border security have always been linked together, and so has the need to find ways to improve security decisions. The United States and bordering countries benefit from the North American Free Trade Agreement (NAFTA), but amongst the positive effects of NAFTA there is a looming drug threat that effects the bi-national supply chains. In 2015 Customs and Border Protections (CBP) processed over 72,000 trucks, rail, and sea containers a day. CBP also seized 3.4 million pounds of narcotics, the majority of them at the ports of entry. With unknown threats using commercial vehicles to transport their illicit …
Wettability Of Nonwoven Polymeric Nanofiber Mats, Edgar Munoz
Wettability Of Nonwoven Polymeric Nanofiber Mats, Edgar Munoz
Theses and Dissertations
The wettability of heterogeneous materials has been attracting special interest by academia and industrial sector given the need to development self-cleaning Nonwoven nanofiber mats have demonstrated potential given its hydrophobicity granted by the ultimate structure of the system, small fiber diameter and small pores giving rise to effects such as the Cassie-Baxter. This thesis analyzed the wettability of a wide range of polymeric systems. Nanofiber mats were manufactured using the Forcespinning® technology. Samples were prepared at different polymeric concentrations and rotational speeds to alter fiber size; density of the mat was also altered to evaluate the effect of porosity on …
Knee Joint Internal Forces During Squat Jump Exercise, Ricardo Moreno
Knee Joint Internal Forces During Squat Jump Exercise, Ricardo Moreno
Theses and Dissertations
The purpose of this research is to investigate muscular ligament and joint contact forces produced during squat jump exercise. An inverse dynamics, two dimensional, leg model is used to describe the motion in the sagittal plane. The lower extremity model includes two bones, tibia and femur, tibio-femoral ligaments, and muscles such as quadriceps, hamstrings, and gastrocnemius. The ligaments are anatomically modeled as nonlinear strings, but the femoral condyle is modeled as a circle and the tibial plateau as a straight line. Experimental squat jump exercises are conducted to obtain the ground reaction forces, the angular accelerations, and centroid linear acceleration …
Development Of A Fundamental Autonomous Ground Vehicle Cruise Control Using Matlab And Simulink, Luis F. Martinez
Development Of A Fundamental Autonomous Ground Vehicle Cruise Control Using Matlab And Simulink, Luis F. Martinez
Theses and Dissertations
This study presents and describes the development of a fully autonomous vehicle cruise control system covering the vehicle dynamics and control design needed to simulate such system. It encompasses obstacle avoidance, intelligent-and-optimal lane change as well as adaptive behavior. This study offers a comprehensive two-dimensional cruise control with three degrees of freedom and it is designed using active obstacle avoidance controllers. It also includes optimized fuzzy logic for optimal vehicle trajectory and an extensive array of control law methodology. The end work shows a complete simulation run using MATLAB and Simulink.
Study Of Selective Laser Remelting Of 316l S.S. To Reduce Roughness On Inclined Surface, Jafar Ghorbani
Study Of Selective Laser Remelting Of 316l S.S. To Reduce Roughness On Inclined Surface, Jafar Ghorbani
Theses and Dissertations
Additive manufacturing (AM) technologies are increasingly competing with subtractive methods, and there are promising applications for additive technologies that are hybrid with traditional manufacturing methods. Poor surface roughness of additive manufactured parts continues to be a major challenge especially for advanced functional parts. In this study, effect of processing parameters are evaluated, optimized and verified by using the Box–Behnken design of experiment method. The results, for the first time, reveal that surface remelting has the potential to become a high speed approach for improving the roughness of non-horizontal surface of additive manufactured parts.
Flow Field Dynamics In A High-G Ultra-Compact Combustor, Andrew E. Cottle
Flow Field Dynamics In A High-G Ultra-Compact Combustor, Andrew E. Cottle
Theses and Dissertations
The Ultra Compact Combustor (UCC) presents a novel solution to the advancement of aircraft gas turbine engine performance. A high-g UCC design operates by diverting a portion of the axial compressor flow into a circumferential combustion cavity positioned about the engine outer diameter. The circumferential cavity (CC) provides the necessary residence length and time for combustion within reduced axial lengths; furthermore, high rates of centrifugal acceleration termed high-g loading are imposed upon the swirling cavity flow. These high-g conditions are hypothesized to increase flame speed, reduce flame length, and improve lean blow-out performance. Work at AFIT was sponsored by the …
Experimental Investigation Of Chicken Manure Pyrolysis And Gasification, Mohamed Hussein Hussein
Experimental Investigation Of Chicken Manure Pyrolysis And Gasification, Mohamed Hussein Hussein
Theses and Dissertations
The dependency on renewable resources of energy in power production is a necessary step that mankind has to take if we want our advances in life and technology to resume. In a century or two, fossil fuels will be depleted, and if we do not start to take action, Energy will be the most expensive and rare item on our planet. Biomass is one of the sources of renewable energy with an advantage of being the closest in characteristics to fossil fuels. The evolved gases are similar to fossil fuel gases which makes itthe easiest source to switch to, with …
In-Situ Optical Microscopic Investigation Of The Dendrite Formation On Lithium Anode Under Different Electrolyte Conditions In Li-S Battery, Tianyao Ding
Theses and Dissertations
By utilizing a high-resolution optical microscope, the dendrite formation on a lithium electrode with different electrolytes suitable for Li-S battery was investigated. It is found that the anions of lithium, the solvents, and the deposition current density have significant effects on the dendrite formation and surface morphology of lithium electrodes in electrolytes without polysulfides. On the contrary, in electrolytes with 25 mM concentration of polysulfides, the dendrite formation and surface morphology tend to be similar regardless of the other conditions. The dendrite-suppression effect of polysulfides, inorganic additive (CsNO3), and electrode modifier (TEOS) are not significant in the electrolytes with polysulfides …
Computational Modeling Of Transient Processes During Run-In For Tribological Systems, Rob Morien
Computational Modeling Of Transient Processes During Run-In For Tribological Systems, Rob Morien
Theses and Dissertations
Understanding the frictional behavior of machine elements in mutual rolling or sliding contact is important for many engineering applications. When frictional sliding is initiated, the tribological system passes through several stages with each stage possessing its own unique frictional property. The initial transition process preceding stationary sliding is usually called “run-in”. During the run-in time interval, surface topographies of frictional contacts as well as lubricant distribution and surface tribofilms reorganize and adjust through asperity deformation and wear processes before reaching the steady state. This surface stability formed during run-in leads to an improvement in frictional performance during steady state operation, …
A Study To Develop An Electronics Chassis Compound Cylinder Pressure Vessel Using Finite Element Modeling, Gordon Randall Straley
A Study To Develop An Electronics Chassis Compound Cylinder Pressure Vessel Using Finite Element Modeling, Gordon Randall Straley
Theses and Dissertations
This thesis develops a process to design and analyze a two-layer compound cylinder pressure vessel utilizing an inner insert to house electronic circuit card assemblies. The process begins with sizing and analysis of a compound cylinder based on analytical formulas and progresses in complexity to a 2-Dimensional plane stress finite element model of the chassis assembly and ends with a computationally expensive 3-Dimensional finite element analysis of the pressure vessel. Comparing the results from the compound cylinder to the electronics chassis, it is observed that the inner insert geometry has a strong influence on the interfacial pressure at the upper …
Extending Time Until Failure During Leaking In Inflatable, Pneumatically Actuated Soft Robots, Joshua Parker Wilson
Extending Time Until Failure During Leaking In Inflatable, Pneumatically Actuated Soft Robots, Joshua Parker Wilson
Theses and Dissertations
Soft robots and particularly inflatable robots are of interest because they are lightweight, compact, robust to impact, and can interact with humans and their environment relatively safely compared to rigid and heavy traditional robots. Improved safety is due to their low mass that results in low-energy collisions and their compliant, soft construction. Inflatable robots (which are a type of soft robot) are also robust to impact and have a high torque to weight ratio. As a result inflatable robots may be used for many applications such as space exploration, search and rescue, and human-robot interaction. One of the potential problems …
Autonomous Goal-Based Mapping And Navigation Using A Ground Robot, Jeffrey L. Ferrin
Autonomous Goal-Based Mapping And Navigation Using A Ground Robot, Jeffrey L. Ferrin
Theses and Dissertations
Ground robotic vehicles are used in many different applications. Many of these uses include tele-operation of the robot. This allows the robot to be deployed in locations that are too difficult or are unsafe for human access. The ability of a ground robot to autonomously navigate to a desired location without a-priori map information and without using GPS would allow robotic vehicles to be used in many of these situations and would free the operator to focus on other more important tasks. The purpose of this research is to develop algorithms that enable a ground robot to autonomously navigate to …
The Feasibility Of Using A Markerless Motion Capture Sensor (Leap MotionTm Controller) Forquantitative Motor Assessment Intended For A Clinical Setting, Clay Jordan Kincaid
The Feasibility Of Using A Markerless Motion Capture Sensor (Leap MotionTm Controller) Forquantitative Motor Assessment Intended For A Clinical Setting, Clay Jordan Kincaid
Theses and Dissertations
Although upper limb motor impairments are common, the primary tools for assessing and tracking these impairments in a clinical setting are subjective, qualitative rating scales that lack resolution and repeatability. Markerless motion capture technology has the potential to greatly improve clinical assessment by providing quick, low-cost, and accurate tools to objectively quantify motor deficits. Here we lay some of the groundwork necessary to enable markerless motion capture systems to be used in clinical settings. First, we adapted five motor tests common in clinical assessments so they can be administered via markerless motion capture. We implemented these modified tests using a …
Feasibility Of Friction Stir Processing (Fsp) As A Method Of Healing Cracks In Irradiated 304l Stainless Steels, Cameron Cornelius Gunter
Feasibility Of Friction Stir Processing (Fsp) As A Method Of Healing Cracks In Irradiated 304l Stainless Steels, Cameron Cornelius Gunter
Theses and Dissertations
The current US fleet of nuclear reactors has been in service for three decades. Over this period, existing welds in stainless steel (SS) shrouds have sustained stress corrosion cracking (SCC) and are in need of repair. Additionally, helium has formed interstitially as a byproduct of proton bombardment. Current repair technology, such as TIG welding, puts extreme amounts of heat into the material and allows for interstitial helium atoms to aggregate and form bubbles/voids at grain boundaries. This significantly weakens the material, proving to be a very counterproductive and ineffective repair technique. Much study has been done on friction stir processing …
Evolvability And Excess Capability As A Response To Uncertain And Future Requirements, Jeffrey Douglas Allen
Evolvability And Excess Capability As A Response To Uncertain And Future Requirements, Jeffrey Douglas Allen
Theses and Dissertations
Product and system designers face many challenges in the modern world. Designing products that will be subject to emerging or uncertain requirements can be one of the most significant of these challenges. A major risk associated with emerging or uncertain requirements is premature obsolescence. Large-scale, complex engineered systems, such as, aircraft, spacecraft, large seagoing vessels, communication and power systems are especially susceptible to this issue. However, this challenge is not limited to only large-scale complex systems. Even relatively simple products can suffer from premature obsolescence and even failure to be initially accepted, due to inadequately understood or changing requirements. One …
Numerical Study Of Erosion Of The Internal Wall Of Sales Gas Piping By Black Powder Particles, Ahmed Saud Al-Haidari
Numerical Study Of Erosion Of The Internal Wall Of Sales Gas Piping By Black Powder Particles, Ahmed Saud Al-Haidari
Theses and Dissertations
Micro particles, primarily from iron, can wreak havoc on a Sales Gas System. For example, the transport of particles with the gas flow can cause erosion damage to the piping system, lead to the release of toxic gasses, and interrupt the operation. The objective of the current work is to examine the erosion rate (ER) in an existing Sales Gas Piping System by simulating different black powder particles sizes and considering variable operation conditions. An elbow-shaped pipe spool is used to determine the area of maximum destruction. It will help the designer, engineer and operation personnel to predict the ER …
Multi-Axial Fiber Optic Reference Strain Sensor For Flexible Dynamics Of Structures, Gabriel Lapilli
Multi-Axial Fiber Optic Reference Strain Sensor For Flexible Dynamics Of Structures, Gabriel Lapilli
Theses and Dissertations
Launch vehicles are in an ever-decreasing weight trend, with bodies becoming more slender to reduce aerodynamic loading. Mass and stiffness tend to be opposing concepts when designing launch vehicles: a stiffer structure means it is usually heavier. Lower stiffness on launch vehicles may produce excessive vibrations during flight, reducing the performance, operating characteristics and safety margins of the vehicle. It also impacts flight dynamics: as the vehicle flies, the orientation of its thrusters and actuators are impacted by the vibrations, creating potential instabilities in the control schemes. This is currently accounted for by using single-point inertial measurements and feeding the …
Real Time Implementation Of An Inertial Measurement Unit Based On Fiber-Bragg Sensor Array Using Legendre Polynomial, Taher Saifee Parekh
Real Time Implementation Of An Inertial Measurement Unit Based On Fiber-Bragg Sensor Array Using Legendre Polynomial, Taher Saifee Parekh
Theses and Dissertations
Missiles and launch vehicle are trending towards becoming more slender in shape to reduce aerodynamic drag. Bending vibrations of the rocket body occur when a flying object with a large slenderness performs pitch or yaw command. The onboard Inertia Measurement Unit (IMU) measures the attitude and the angular velocities of the deflected body as well as the rigid body motion and in turn feeds these signals back to the control loop. Feedback of the vibrating information degrades the control system stability and in the worst case makes the system unstable. These effects become more significant when the slenderness ratio of …
Design Of A Rotating Brush Underwater Grooming Device With A Focus On Brush Optimization, Motor Control And Design For Reliability, Mark Harrison Nanney
Design Of A Rotating Brush Underwater Grooming Device With A Focus On Brush Optimization, Motor Control And Design For Reliability, Mark Harrison Nanney
Theses and Dissertations
The design and control of Remotely Operated Vehicles (ROV) to groom or clean the underwater surface of ship hulls is becoming an important aspect of the maintenance of vessels to the United States Navy. The biological growth below the waterline of the vessels can be the cause for drag penalties near 21% causing up to 32% increase in shaft power at 15 knots (Schultz, 2007). Research conducted by the Center for Corrosion and Biofouling Control at Florida Institute of Technology (FIT) indicated that weekly grooming can prevent high profile biological growth (Hearin, et al., 2015). The design of a rotating …
An Improved Fuel Spray Breakup Model For Advanced Internal Combustion Engine Configurations, Chitra Sadanandan
An Improved Fuel Spray Breakup Model For Advanced Internal Combustion Engine Configurations, Chitra Sadanandan
Theses and Dissertations
Lack of oil resources and increasing effects of global warming have emphasized and led to stricter regulation standards. To meet the current demands, the engines need to be highly efficient in terms of fuel efficiency and performance. One of the fundamental ways to achieve this goal is by studying the fuel atomization and the combustion process. However, there are several challenges involved in studying the process of atomization and combustion only through experimental approaches as they involve numerous parameters. A suitable supplement or alternative to the experimental approach is the numerical approach. Advances in high performance computing, have led to …
The Design Of An Articulating Five-Headed In-Water Grooming Tool To Maintain Ships Free Of Fouling, Caglar Erdogan
The Design Of An Articulating Five-Headed In-Water Grooming Tool To Maintain Ships Free Of Fouling, Caglar Erdogan
Theses and Dissertations
Biofouling is a major concern to ship owners. Biofouling increases hull roughness, increasing the frictional resistance and fuel consumption while decreasing maximum speed. Finding a way to maintain hulls free from fouling has, therefore, become a research challenge for scientists and engineers. Grooming has been proposed as a novel method for controlling fouling (Tribou and Swain 2010). It refers to the regular proactive light cleaning to maintain the hull free of fouling with minimal impact to ship coatings. The purpose of this thesis is to design, build, and deploy a compliant multiheaded grooming tool which utilized five polypropylene vertically rotating …
A Robot Platform For Intelligent Ground Vehicle Research, Jihang Li
A Robot Platform For Intelligent Ground Vehicle Research, Jihang Li
Theses and Dissertations
This thesis presents a mobile platform developed for further research on the Intellegent Ground Vehicle project which began as a capstone project but without achieving full autonomy. The scope of the current project is to develop Robot Operating System (ROS) based driver libraries to the electronic system and provide application program interfaces (APIs) for higher abstraction level libraries. Prior work had provided a mechanical system and several sensors for the robot. The chassis of the vehicle is fabricated with aluminum tubings and enclosed with aluminum boards to protect internal electronics from environmental conditions. A three-wheel differential drive architecture is used …
On Phase Change Material Heat Exchangers: A Computational And Experimental Investigation, Christian Omar Rodriguez Dieppa
On Phase Change Material Heat Exchangers: A Computational And Experimental Investigation, Christian Omar Rodriguez Dieppa
Theses and Dissertations
The emergence of ground- and airborne-based high energy laser (HEL) weapon systems has created a need for high-rate thermal energy storage (TES) devices that meet demanding size, weight, and power (SWaP) requirements for integration into the HEL thermal management system (TMS). Current and near-term HEL weapon systems produce thermal loads on the order of 30-300 kW when emitting, and approximately 5-10% of the peak load when in a non-emitting standby state. Emission to standby duty cycles of 10-50% are common, and therefore, sizing the TMS for real-time rejection of the peak thermal load is not practical. Accordingly, TES components can …
Haptic Shape-Based Management Of Robot Teams In Cordon And Patrol, Samuel Jacob Mcdonald
Haptic Shape-Based Management Of Robot Teams In Cordon And Patrol, Samuel Jacob Mcdonald
Theses and Dissertations
There are many current and future scenarios that require teams of air, ground or humanoid robots to gather information in complex and often dangerous environments, where it would be unreasonable or impossible for humans to be physically present [1-6]. The current state of the art involves a single robot being monitored by one or many human operators [7], but a single operator managing a team of autonomous robots is preferred as long as effective and time-efficient management of the team is maintained [8-9]. This is limited by the operator's ability to command actions of multiple robots, be aware of robot …
Quantification Of Frictional Drag Due To Biofouling On In-Service Ships, John Travis Hunsucker
Quantification Of Frictional Drag Due To Biofouling On In-Service Ships, John Travis Hunsucker
Theses and Dissertations
The purpose of this research was to improve the quantification of frictional drag due to biofouling on in-service ships by advancing the knowledge and methodology used to study the interactions between fouling communities and the surrounding environment. This research examined the influence of hydrodynamic stress on the development and frictional drag of fouling communities that developed on a fouling release coating; investigated the reliability of using ship performance monitoring to detect changes in the hull and propeller condition; and evaluated the feasibility of developing a field deployable instrument capable of measuring the local frictional resistance on a ship hull in …