Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

2015

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1 - 30 of 11190

Full-Text Articles in Engineering

Laboratory Studies Of The Biodegradation Of Chemically Dispersed Oil: Effect Of Droplet Size And Nutrient Amendment, Christopher D'Ambrose Dec 2015

Laboratory Studies Of The Biodegradation Of Chemically Dispersed Oil: Effect Of Droplet Size And Nutrient Amendment, Christopher D'Ambrose

Dissertations

Oil spills could have devastating effects on the shorelines, and for this reason, chemical dispersants are commonly used to disperse the oil slick in the water column, preventing it from reaching the shorelines. However, the long term fate of dispersed oil depends on its biodegradation by indigenous microorganisms, which in turn depends on the concentration of nutrients in water and on the droplet size distribution.

Using water from the shorelines of Atlantic City, we placed the water with oil and dispersant inside EPA Baffled Flasks and placed them on rotatory shakers. We selected two speeds: high (250 rpm) and low ...


Generalized Dft: Extensions In Communications, Yuewen Wang Dec 2015

Generalized Dft: Extensions In Communications, Yuewen Wang

Dissertations

Discrete Fourier Transform (DFT) is a restricted version of Generalized DFT (GDFT) which offers a very limited number of sets to be used in a multicarrier communication system. In contrast, as an extension on Discrete Fourier Transform (DFT) from the linear phase to non-linear phase, the proposed GDFT provides many possible carrier sets of various lengths with comparable or better performance than DFT. The availability of the rich library of orthogonal constant amplitude transforms with good performance allows people to design adaptive systems where user code allocations are made dynamically to exploit the current channel conditions in order to deliver ...


Understanding Bulk Behavior Of Particulate Materials From Particle Scale Simulations, Xiaoliang Deng Dec 2015

Understanding Bulk Behavior Of Particulate Materials From Particle Scale Simulations, Xiaoliang Deng

Dissertations

Particulate materials play an increasingly significant role in various industries, such as pharmaceutical manufacturing, food, mining, and civil engineering. The objective of this research is to better understand bulk behaviors of particulate materials from particle scale simulations.

Packing properties of assembly of particles are investigated first, focusing on the effects of particle size, surface energy, and aspect ratio on the coordination number, porosity, and packing structures. The simulation results show that particle sizes, surface energy, and aspect ratio all influence the porosity of packing to various degrees. The heterogeneous force networks within particle assembly under external compressive loading are investigated ...


Normal-Strength And High-Strength Concrete Columns Under Cyclic Axial Load And Biaxial Moment, Mehdi Zarei Dec 2015

Normal-Strength And High-Strength Concrete Columns Under Cyclic Axial Load And Biaxial Moment, Mehdi Zarei

Dissertations

The technique of using Carbon Fiber Reinforced Polymer (CFRP) materials to repair and strengthen various concrete members has become popular in the structural retrofitting field as an effective way to enhance the strength and ductility of concrete members due to its superior mechanical properties. In this study a method was introduced to study the behavior of concrete columns with and without CFRP jackets under constant axial load and variable lateral load. The lateral load was applied monotonically and cyclically. To predict the behavior of concrete columns under monotonic and cyclic compressive loadings, a computer code was developed to produce the ...


How Can We Build A Moral Robot?, Kristen E. Clark Dec 2015

How Can We Build A Moral Robot?, Kristen E. Clark

Capstones

Artificial intelligence is already starting to drive our cars and make choices that affect the world economy. One day soon, we’ll have robots that can take care of our sick and elderly, and even rescue us in rescue us in emergencies. But as robots start to make decisions that matter—it’s raising questions that go far beyond engineering. We’re stating to think about ethics.

Bertram Malle and Matthias Scheutz are part of a team funded by the department of defense. It's their job to answer a question that seems straight out of a sci-fi novel: How ...


Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma Dec 2015

Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma

Theses

In most industrial applications, stirred tanks and reactors are typically provided with baffles to improve their mixing characteristics. However, in a number of pharmaceutical production facilities unbaffled vessels are commonly used. The absence of baffles is preferred in such cases because it reduces the potential for contamination and makes cleaning the vessel between batches easier. However, the lack of baffles also has a negative impact on the system’s hydrodynamics since it often results in poor mixing of the batch, especially if the impeller is centrally placed, since the liquid in such a system is subject to a strong tangential ...


Investigating Neural Mechanisms Of Hand Movements In Virtual Reality, Chuang Mu Dec 2015

Investigating Neural Mechanisms Of Hand Movements In Virtual Reality, Chuang Mu

Theses

Mirror visual feedback (MVF), a technique by which movement of one limb is perceived as movement of the contralateral limb, has the capacity to relieve phantom limb pain or promote motor recovery of the upper limbs after stroke (Ramachandran et al., 1995). Functional MRI studies have demonstrated activation of the motor areas in the hemisphere ipsilateral to the moving hand in response to MVF. However, the neural mechanisms of MVF are still unclear. This Electroencephalography (EEG) study was designed to investigate the timing of neural responses to MVF presented in virtual reality. 16 right-handed, neurologically healthy subjects participated in a ...


A Preliminary Investigation Of The Sterile-Filterability Of Bcs Class Ii Drug Nanosuspensions Prepared Via Wet Stirred Media Milling, Parul Ohri Dec 2015

A Preliminary Investigation Of The Sterile-Filterability Of Bcs Class Ii Drug Nanosuspensions Prepared Via Wet Stirred Media Milling, Parul Ohri

Theses

Drug nanoparticles can achieve targeting capabilities, enhanced dissolution rates and improved bioavailability when injected intravenously. Sterile filtration of drug nanoparticle suspensions (nanosuspensions) is critically needed for administration by intravenous delivery route. Avoiding gamma irradiation and high temperatures, sterile filtration could be an effective process to sterilize drug nanosuspensions. On the other hand, two major challenges must be tackled: drug particles must at least be smaller than the filter pore size and minimum amount of non-toxic stabilizers must be used to prevent side effects like pain on the injection site. The aim of this study is to prepare naproxen (NPX) nanosuspensions ...


Comparison Of Muscle Synergies Elicited From Transcranial Meganetic Stimulation (Tms) And Voluntary Movements, Yifei Wei Dec 2015

Comparison Of Muscle Synergies Elicited From Transcranial Meganetic Stimulation (Tms) And Voluntary Movements, Yifei Wei

Theses

A key question in motor control is the redundancy of musculoskeletal elements involved. This problem refers to as the degree of freedom problem. The Muscle Synergy Hypothesis is one of the hypotheses that aim to resolve the problem which defines that a muscle synergy is a combination of a small set of muscles activated at different levels, serving as a building block that constructs motor behaviors. A recent study (Overduin et al. 2012) demonstrated that muscle synergies decomposed by Nonnegative Matrix Factorization (NMF) from EMG patterns evoked by intra-cortical microsimulation (ICMS) in the monkey remarkably matched ones observed in naturalistic ...


Synthesis Of A Renewable Sourced Thermotropic Polyester With 2,5-Furandicarboxylic Acid, Alicia Marie Marguerite Hurst Dec 2015

Synthesis Of A Renewable Sourced Thermotropic Polyester With 2,5-Furandicarboxylic Acid, Alicia Marie Marguerite Hurst

Theses

With the rapid depletion of non-renewable sourced materials, unpredictable fluctuations in the prices of fossil fuels, and increased environmental awareness the need to develop biobased materials grows ever more desperate. Furan derivatives sourced from hexoses provide a promising solution for replacing petrochemical based materials. One furan derivative in particular, 2,5-furandicarboxylic acid (FDCA), is especially promising due to its structural similarity to terephthalic acid and potential for use in the production of polyesters similar to PET, PPT, and PBT. This study investigated the synthesis, thermal and liquid crystalline properties of a totally renewable sourced thermotropic polyester based on FDCA. Fructose ...


Plasticity Of The Cortical Representation Of Finger Extensors Induced By Paired Associative Stimulation, Ian Anthony Gerard Lafond Dec 2015

Plasticity Of The Cortical Representation Of Finger Extensors Induced By Paired Associative Stimulation, Ian Anthony Gerard Lafond

Dissertations

This dissertation first explored associative plasticity of the human motor cortical representation with the use of noninvasive transcranial magnetic stimulation (TMS) paired with peripheral electrical stimulation. Paired Associative Stimulation (PAS) has grown in popularity because of its potential clinical applications. PAS techniques are used in combination with electromyography (EMG) measurements to study cortical excitability and features of hand movement. This work focuses on a cohesive approach to answer central questions about: the ideal mechanism to facilitate cortical plasticity via PAS, the interaction between the behavior performed and type of stimulation delivered to the targeted cortical network and the effects of ...


An Fpga Implementation Of A Sleep Enabled Pon System, Zheyu Liu Dec 2015

An Fpga Implementation Of A Sleep Enabled Pon System, Zheyu Liu

Theses

Owing to the growing demand for bandwidth-hungry video-on-demand applications, Passive Optical Network (PON) has been widely considered as one of the most promising solutions for broadband access. Environmental concerns motivated network designers to lower energy consumption of optical access networks. A well-known approach to reduce energy consumption is to allow network elements to switch to the sleep mode.

In this framework, an improved Optical network Unit (ONU) architecture in TDM-PON is proposed to reduce the handover time of status switching. Energy-saving performances of current and improved architectures are compared in different scenarios. The simulation results show that by applying a ...


Thermoelectric Properties Of Silicon-Germanium Alloys, Aniket Annasaheb Maske Dec 2015

Thermoelectric Properties Of Silicon-Germanium Alloys, Aniket Annasaheb Maske

Theses

Direct energy conversion from thermal to electrical energy, based on thermoelectric effects, is attractive for potential applications in waste heat recovery and environmentally friendly refrigeration. The energy conversion efficiency of thermoelectric devices is related to the thermoelectric figure of merit ZT, which is proportional to the electrical conductivity, the square of the Seebeck coefficient, and the inverse of the thermal conductivity. Currently, the low ZT values of available materials restrict the large scale applications of this technology. Recently, however, significant enhancements in ZT have been reported in nanostructured materials such as super-lattices mainly due to their low thermal conductivities. According ...


Rodent Testing Device Surrogate For Shockwave Blast Testing, Anthony C. Misistia Dec 2015

Rodent Testing Device Surrogate For Shockwave Blast Testing, Anthony C. Misistia

Theses

Many laboratories around the world are conduct shockwave blast injury tests on rodents to simulate blast traumatic brain injury (TBI). Each of these laboratories has different techniques for creating the shockwave blasts as well as positioning the rats. There is no device to determine whether or not the rodent animal models actually experiences a true blast wave in a given set up. This device was developed as a method for verifying rodents undergoing true shockwave blasts through biometrics, instrumentation and the basic biomechanical responses a rodent experiences during such tests. Since the goal of shockwave blast testing is to replicate ...


A Study Of Kinematics And Kinetics In Time-Constrained Arm Movements, Oyindamola Owoeye Dec 2015

A Study Of Kinematics And Kinetics In Time-Constrained Arm Movements, Oyindamola Owoeye

Theses

Several studies such as the equilibrium point hypothesis (EPH) purport that the motor signals that descend from the brain instead of encoding muscle torques, influence an existing relationship between muscle torque and body configuration.

In the present study, the possibility of torque depending explicitly on position was tested using a task in which subjects (N=5) moved a simulated weightless frictionless mass through a small (<8 degree) elbow extension in order to move a cursor on a screen to a target location. Each subject completed 720 trials. On ~10% of trials the simulated mass was increased unknown to the subject. The relationship between the cursor’s position and the torque applied to the system was held constant even when the simulated mass was increased. Thus, any change in torque produced was neither due the subjects’ perception of the mass nor due to their perception of the cursor. The time at which the subjects torque changed direction was seen to be significantly different (p<0.005) during trials which the mass changed. This change in torque is concluded to be position-dependent. However the possibility of this being a merely mechanical effect could not be ruled out by due to poor EMG collection.

A post-hoc analysis of different position-dependent motor control models, was done. Particularly, an exponential spring model, a linear spring model, and a linear spring with relative damping model were each tested to see how well ...


Shock Wave Interaction With A Fluid Filled Cylinder Experimental Methods, Praveen Kumar Baba Siddabattuni Dec 2015

Shock Wave Interaction With A Fluid Filled Cylinder Experimental Methods, Praveen Kumar Baba Siddabattuni

Theses

In the recent wars of Iraq and Afghanistan, many soldiers sustained bTBI (blast-induced traumatic brain injury). The blasts are created by extensive use of improvised explosive devices (IED’s). Whether pure blast-shock waves cause TBI or what is the mechanism of injury are not fully known. Research efforts are underway to find answers to these questions.

The primary objective of this project is to understand how the shockwave interacts with a fluid-filled cylinder of different thicknesses. Here, the cylinder is idealized as head and the fluid filled inside it as the brain material. The primary interest here is, how the ...


Realization Of Dynamixel Servo Plant Parameters To Improve Admittance Control For A Compliant Human-Robot Interaction, Ahmad Zahid Rao Dec 2015

Realization Of Dynamixel Servo Plant Parameters To Improve Admittance Control For A Compliant Human-Robot Interaction, Ahmad Zahid Rao

Theses

In theory, admittance control offers a very effective method of implementing smooth human-robot interaction. It allows the user’s applied force to control the movement of a powerful robot as if the robot were a small, passive mass. However, the real-world application of admittance control faces limitation posed by the dynamics of servo motors, the accuracy of the force sensors, and the computation speed of processors.

This research investigates the limitations on achieving compliant passive behavior when using state-of-the-art actuators, sensors and processors. The work involves characterizing the dynamic behavior of the servo motors, development of improved differential equations representing ...


Verification Of Emotion Recognition From Facial Expression, Yanjia Sun Dec 2015

Verification Of Emotion Recognition From Facial Expression, Yanjia Sun

Dissertations

Analysis of facial expressions is an active topic of research with many potential applications, since the human face plays a significant role in conveying a person’s mental state. Due to the practical values it brings, scientists and researchers from different fields such as psychology, finance, marketing, and engineering have developed significant interest in this area. Hence, there are more of a need than ever for the intelligent tool to be employed in the emotional Human-Computer Interface (HCI) by analyzing facial expressions as a better alternative to the traditional devices such as the keyboard and mouse.

The face is a ...


Numerical-Analytical Assessment On Solar Chimney Power Plant, Nima Fathi, Seyed Sobhan Aleyasin, Peter Vorobieff Dec 2015

Numerical-Analytical Assessment On Solar Chimney Power Plant, Nima Fathi, Seyed Sobhan Aleyasin, Peter Vorobieff

Nima Fathi

This study considers an appropriate expression to estimate the output power of solar chimney power plant systems (SCPPS). Recently several mathematical models of a solar chimney power plant were derived, studied for a variety of boundary conditions, and compared against CFD calculations. An important concern for modeling SCPPS is about the accuracy of the derived pressure drop and output power equation. To elucidate the matter, axisymmetric CFD analysis was performed to model the solar chimney power plant and calculate the output power for different available solar irradiation. Both analytical and numerical results were compared against the available experimental data from ...


System-Wide Prediction Of General, All-Cause, Preventable Hospital Readmissions, Ken Musselman, Brandon Pope, Steve Witz, Zhiyi Tian, Lingsong Zhang, Linda Leon, Ann Davis Dec 2015

System-Wide Prediction Of General, All-Cause, Preventable Hospital Readmissions, Ken Musselman, Brandon Pope, Steve Witz, Zhiyi Tian, Lingsong Zhang, Linda Leon, Ann Davis

RCHE Publications

Existing studies of hospital readmissions typically focus on specific diagnoses, age groups, discharge dispositions, payer classes, or hospitals, and often use small samples. It is not clear how predictive models generated from such studies generalize across diseases, hospitals, or time periods. In this study, a logistic regression model of readmission risk within 30 days based on hospital administrative data was constructed and validated across hospitals and time periods. The hospitals included both general and specialty hospitals such as long-term care, women’s, and children’s hospitals. The administrative data included information on patient’s demographics, diagnoses, procedures, and discharge disposition ...


Demonstration Of Inexact Computing Implemented In The Jpeg Compression Algorithm Using Probabilistic Boolean Logic Applied To Cmos Components, Christopher I. Allen Dec 2015

Demonstration Of Inexact Computing Implemented In The Jpeg Compression Algorithm Using Probabilistic Boolean Logic Applied To Cmos Components, Christopher I. Allen

Theses and Dissertations

Probabilistic computing offers potential improvements in energy, performance, and area compared with traditional digital design. This dissertation quantifies energy and energy-delay tradeoffs in digital adders, multipliers, and the JPEG image compression algorithm. This research shows that energy demand can be cut in half with noisesusceptible16-bit Kogge-Stone adders that deviate from the correct value by an average of 3 in 14 nanometer CMOS FinFET technology, while the energy-delay product (EDP) is reduced by 38 . This is achieved by reducing the power supply voltage which drives the noisy transistors. If a 19 average error is allowed, the adders are 13 times more ...


Comparison Of Novel Carboneous Structures To Treat Nitroaromatic Impacted Water, Benjamin M. Doane Dec 2015

Comparison Of Novel Carboneous Structures To Treat Nitroaromatic Impacted Water, Benjamin M. Doane

Theses and Dissertations

Carboneous materials such as carbon nanotube (CNT), granular activated carbon (GAC), and biochar are promising materials for the removal of organic contaminants from aqueous phase solutions. CNTs have astonishing mechanical strength, chemical and thermal stability and high surface area. While biochar, similar to GAC, having an extremely porous structure and high surface area, can be produced in more austere conditions with native materials. In this study, novel CNT-Hybrid structures (CNT-HS), hardwood pellet (HWP) Biochar and standard GAC (F-600 GAC) were used as adsorbents to treat water contaminated by a model nitroaromatic compound, 2,4-dinitrotoluene (DNT).


Collecting Unsolicited User-Generated Change Requests, Joseph W. Goldsmith Dec 2015

Collecting Unsolicited User-Generated Change Requests, Joseph W. Goldsmith

Theses and Dissertations

Unlike aircrew directly associated with acquisitions, line operators are not fully engaged in the methods to push materiel hardware or software change requests up the chain, to a decision maker, and then to the engineers. The Air Force trains these end users to logically apply expert systems knowledge to execute the mission but has not fully leveraged this resource for properly identifying and correcting operational shortfalls in an aircraft's design. Focusing on the Remotely Piloted Aircraft (RPA) community, the research goal is to determine if the Air Force should establish a formal program for collecting and prioritizing unsolicited user ...


Continuous Decision Support, Jeremy P. Hendrix Dec 2015

Continuous Decision Support, Jeremy P. Hendrix

Theses and Dissertations

Organizations are often faced with portfolio construction efforts that require them to select one or more alternatives, subject to resource constraints, with the aim of achieving the maximum value possible. This is a well-defined problem with a number of analytically defensible approaches, provided the entire set of alternatives is known when the decision event takes place. Less well treated in the literature is how to approach this problem when the entire set of alternatives is unknown, as when the alternatives arrive over time. This change in the availability of data shifts the problem from one of identifying an optimal subset ...


Feature Selection And Classifier Development For Radio Frequency Device Identification, Trevor J. Bihl Dec 2015

Feature Selection And Classifier Development For Radio Frequency Device Identification, Trevor J. Bihl

Theses and Dissertations

The proliferation of simple and low-cost devices, such as IEEE 802.15.4 ZigBee and Z-Wave, in Critical Infrastructure (CI) increases security concerns. Radio Frequency Distinct Native Attribute (RF-DNA) Fingerprinting facilitates biometric-like identification of electronic devices emissions from variances in device hardware. Developing reliable classifier models using RF-DNA fingerprints is thus important for device discrimination to enable reliable Device Classification (a one-to-many looks most like assessment) and Device ID Verification (a one-to-one looks how much like assessment). AFITs prior RF-DNA work focused on Multiple Discriminant Analysis/Maximum Likelihood (MDA/ML) and Generalized Relevance Learning Vector Quantized Improved (GRLVQI) classifiers. This ...


Effects Of Automation On Aircrew Workload And Situation Awareness In Tactical Airlift Missions, David R. Meyer Dec 2015

Effects Of Automation On Aircrew Workload And Situation Awareness In Tactical Airlift Missions, David R. Meyer

Theses and Dissertations

In tactical aviation, decision superiority brought upon by high situation awareness remains the arbiter of combat effectiveness. The advancement of sophisticated avionics and highly automated cockpits has allowed for the reduction of aircrew size, and in certain platforms, removal of the crew from the aircraft entirely. However, these developments have not reduced the complex and dynamic interaction between situation awareness and crew workload. While many predictive and experimental methods of evaluating workload exist, situation awareness can only be measured by conducting trials with human operators in a functional prototype. This thesis proposes an innovative methodology to predicatively determine situation awareness ...


Optimal Attitude Control Of Agile Spacecraft Using Combined Reaction Wheel And Control Moment Gyroscope Arrays, Cole C. Doupe Dec 2015

Optimal Attitude Control Of Agile Spacecraft Using Combined Reaction Wheel And Control Moment Gyroscope Arrays, Cole C. Doupe

Theses and Dissertations

This dissertation explores the benefits of combined control moment gyroscope (CMG) and reaction wheel array (RWA) actuation for agile spacecraft. Agile spacecraft are capable of slewing to multiple targets in minimum time. CMGs provide the largest torque capability of current momentum exchange actuation devices but also introduce singularity events in operation. RWAs produce less torque capability than CMGs but can achieve greater pointing accuracy. In this research, a combined RWA and CMG (RWCMG) system is evaluated using analytical simulations and hardware experiments. A closed-loop control scheme is developed which takes advantage of the strengths of each actuator set.The CMGs ...


Creep And Oxidation Of Hafnium Diboride-Based Ultra High Temperature Ceramics At 1500°C, Anthony J. Degregoria Dec 2015

Creep And Oxidation Of Hafnium Diboride-Based Ultra High Temperature Ceramics At 1500°C, Anthony J. Degregoria

Theses and Dissertations

Ultra high temperature ceramics (UHTCs) are leading candidates for aerospace structural applications in high temperature environments, including the leading edges of hypersonic aircraft and thermal protection systems for atmospheric re-entry vehicles. Before UHTCs can be used in such applications, their structural integrity and environmental durability must be assured, which requires a thorough understanding and characterization of their creep and oxidation behavior at relevant service temperatures.


Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 800°C In Air And In Silicic Acid-Saturated Steam, Scott J. Robertson Dec 2015

Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 800°C In Air And In Silicic Acid-Saturated Steam, Scott J. Robertson

Theses and Dissertations

A facility was demonstrated that successfully resolved problems highlighted by previous attempts to study SiC fibers in steam. Monotonic tension and creep tests were conducted to characterize the fibers. The tensile strength of the fibers showed little dependence on applied stress rate, indicating a resistance to environmentally assisted crack growth. Climb-controlled diffusion in air and grain boundary sliding in silicic acid-saturated steam were the dominant damage mechanisms. Silicic acid-saturated steam had a degrading effect on the mechanical performance of the fibers, but much less than unsaturated steam environments. The Monkman-Grant relationship was demonstrated for Hi-NicalonTM S fibers and may be ...


Optimal Uas Assignments And Trajectories For Persistent Surveillance And Data Collection From A Wireless Sensor Network, Nidal M. Jodeh Dec 2015

Optimal Uas Assignments And Trajectories For Persistent Surveillance And Data Collection From A Wireless Sensor Network, Nidal M. Jodeh

Theses and Dissertations

This research developed a method for multiple Unmanned Aircraft Systems (UAS) to efficiently collect data from a Wireless Sensor Networks (WSN). WSN are composed of any number of fixed, ground-based sensors that collect and upload local environmental data to over flying UAS. The three-step method first uniquely assigns aircraft to specific sensors on the ground. Second, an efficient flight path is calculated to minimize the aircraft flight time required to verify their assigned sensors. Finally, sensors reporting relatively higher rates of local environmental activity are re-assigned to dedicated aircraft tasked with concentrating on only those sensors. This work was sponsored ...