Engineering Commons^™

Identifying Expert Investors On Financial Microblog Via Artificial Neural Networks, Pierluca Del Buono

Dissertations

In the recent years, thanks to social media platform, a plethora of information has been available to financial investors, that were traditionally dependent from financial institutions advisors. Strategies are now shared among web users, performances of stocks are commented in web communities and hints and suggestions are travelling on the internet with a fast pace, in a way that was unthinkable few years before. Several attempts have been made in the recent past, to predict Market movements and trends from activity of Financial Social Networks participants, and to evaluate if contributions from individuals with high level of expertise distinguish themselves …

Numerical Simulation Of Fault Impacts For Commercial Walk-In Freezers, Alireza Behfar, David P. Yuill

Durham School of Architectural Engineering and Construction: Faculty Publications

Refrigeration systems can undergo many faults that could negatively affect their operation and performance. This paper describes a modeling process to simulate the fault impacts on the operation of a commercial walk-in freezer using semi-empirical models. These models often require less modeling effort than full forward models and could be used in scenarios where detailed information is missing, such as in field-measured systems. An important characteristic of a typical walk-in refrigeration system is the existence of a liquid-line receiver after the condenser, which significantly changes the behavior of the cycle, in comparison to a receiver-less system. Component models described in …

Robust Nonlinear Estimation And Control Applications Using Synthetic Jet Actuators, Natalie Ramos Pedroza

Doctoral Dissertations and Master's Theses

Limit cycle oscillations (LCO), also known as utter, cause significant challenges in flight control of small unmanned aerial vehicles (SUAVs), and could potentially lead to structural damage and catastrophic failures. LCO can be described as vibrational motions in the rocking, pitching and plunging displacements of an aircraft wing. To address this, the use of synthetic jet actuators (SJAs) in UAV flight control systems is becoming popular as a practical alternative and to mechanical deflection surfaces.

Synthetic jet actuators are promising tools for LCO suppression systems in small UAVs due to their small size, ease of operation, and low cost. Uncertainties …

Design And Optimization Of Aircraft Configuration For Minimum Drag, Zin Win Thu, Aung Myo Thu, Phyo Wai Thaw

International Journal of Aviation, Aeronautics, and Aerospace

This paper presents a reliable and robust optimization for minimum drag of an aircraft at the conceptual design phase. Firstly, the conceptual design code was developed and existing Single Seat Aerobatic (SSA) aircraft was chosen to validate the reliability of developed code. The resulted data from the developed code showed good agreement with the existing data. Secondly, Sequential Quadratic Programming (SQP) optimizer was created and employed as a tool to explore possible aircraft configurations that are more efficient and less costly than an existing design. The optimized results gave lower Drag and better performance.

Mental Health In Commercial Aviation - Depression & Anxiety Of Pilots, Maurice C. Dehoff, Stephen K. Cusick

International Journal of Aviation, Aeronautics, and Aerospace

Two landmark accidents invigorated the discussion regarding pilot mental health. Other incidents may also have a mental health component that is related to, but not the direct cause of, the event. It is suspected that these “other incidents” are much more commonplace and while not catastrophic, erode safety. Depression and anxiety are two commonly occurring mental health concerns. Research indicates that a considerable portion of the U. S. population suffers from some form of mental health issue. Most go undiagnosed and untreated. A similar rate of occurrence appears to be found within the airline pilot population. The stigma of mental …

Called To Safety? Individual And Combined Effects Of Safety Climate And Occupational Callings On Aviator Safety Performance, Michele W. Gazica, Erin E. Bowen, Michael A. Mccarson, Kristen A-M. Chadwell

Journal of Aviation/Aerospace Education & Research

This study examined the individual and combined effects of two potential antecedents to aviation-related safety performance: safety climate and occupational callings. Research exploring the importance of occupational callings to the safety domain is in its nascent stages. The extent that someone is living a calling may explain variance in actual safety performance above that which can be explained by safety climate alone. Survey data from aviators in a flight training program were analyzed to evaluate the ability of occupational calling assessments to inform the potential for safety mishaps within the aviation industry. Results indicate that both safety climate and occupational …

Adaptive Learning Pedagogy Of Universal Design For Learning (Udl) For Multimodal Training, Ziho Kang, Mattlyn R. Dragoo, Lauren Yeagle, Randa L. Shehab, Han Yuan, Lei Ding, Stephen G. West

Journal of Aviation/Aerospace Education & Research

Traditionally, students or trainees usually receive training through a unidirectional instructional approach that can lack interactive activities or through a single material source in classrooms. Therefore, it is possible that some trainees might encounter a sink-or-swim situation if they are not able to understand the materials presented during classroom lectures nor execute correct procedures during laboratory sessions with time-intensive training. To address this issue, the Universal Design for Learning (UDL) asserts that trainees can increase their performance if instructors can provide the trainees with diversified means of information representation, expression opportunities, and engagement means. However, we lack the framework on …

Human Error Analysis Of Helicopter Emergency Medical Services (Hems) Accidents Using The Human Factors Analysis And Classification System (Hfacs), Paul E. Cline

Journal of Aviation/Aerospace Education & Research

Helicopter Emergency Medical Services (HEMS) is among the most dangerous type of flying in commercial aviation. This research utilized the Human Factors Analysis and Classification System (HFACS) to understand the errors, preconditions and violations that contribute to these accidents. Drawing upon source data from the National Transportation Safety Board’s Aviation Accident Database, HEMS accidents from 2000-2016 were analyzed according to the HFACS framework.

The Impact Of Functional Modeling On Engineering Students' Mental Models, Jacob T. Nelson

Senior Honors Projects, 2010-2019

The ability to understand complexity and think holistically about systems is an increasingly important part of engineering design. This is embodied in the concept of systems thinking, a concept studied primarily in the fields of systems dynamics and systems engineering. Systems thinking ability is built off mental models, a loosely-defined construct people form to make predictions about their surroundings. Methods to evaluate systems thinking and underlying mental models rely primarily on self-evaluative methods such as questionnaires, or detailed simulations of systems or processes; however these methods fail to directly capture students’ design tendencies. This work presents a visual instrument used …

Engineering Identity Development: A Review Of Higher Education Literature, Sarah L. Rodriguez, Charles Lu, Morgan Bartlett

Faculty Publications

The purpose of this systematic literature review was to appraise and synthesize the current scholarship pertaining to engineering identity development within the higher education context and create recommendations for future scholarship within engineering education. A review of the literature concluded that research on engineering identity development has increased over the past ten years, has been conducted primarily with qualitative methods, and has been primarily limited to academic communities focused on mathematics, science, and engineering education. In addition, current scholarship reflected that most of the work in this area has focused on the learning contexts and experiences of women and underrepresented …

Table Of Contents, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Journal Of The Arkansas Academy Of Science- Volume 72 2018, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Keynote Address And Meeting Program Report, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Forecasting Changes In Religiosity And Existential Security With An Agent-Based Model, Ross J. Gore, Carlos Lemos, F. Leron Shults, Wesley J. Wildman

VMASC Publications

We employ existing data sets and agent-based modeling to forecast changes in religiosity and existential security among a collective of individuals over time. Existential security reflects the extent of economic, socioeconomic and human development provided by society. Our model includes agents in social networks interacting with one another based on the education level of the agents, the religious practices of the agents, and each agent's existential security within their natural and social environments. The data used to inform the values and relationships among these variables is based on rigorous statistical analysis of the International Social Survey Programme Religion Module (ISSP) …

Combined Effect Of Storm Surge And Overland Flow On Flooding In A Coastal Urban Area, Navid Tahvildari, Akash Sahu, Yawen Shen, Mohamed Morsy, Jonathan Goodall

Civil & Environmental Engineering Faculty Publications

The coastal regions in the U.S. East Coast and the Gulf of Mexico are under the risk of storm surge and precipitation-driven flooding. The adverse impacts of climate change including sea level rise (SLR), potential increase in intensity and frequency of extreme storms, and increase in precipitation intensity increases the vulnerability of coastal communities to flooding. The common practice for flood hazard assessment in urban coastal areas can result in some errors as the effect of storm surge and overland flow are not considered simultaneously. In this study, we combine the results of two hydrodynamic models, one for overland flow …

Towards Blockchain Empowered Trusted And Accountable Data Sharing And Collaboration In Mobile Healthcare Applications, Xueping Liang, Sachin Shetty, Deepak Tosh, Daniel Bowden, Laurent Njilla, Charles Kamhoua

VMASC Publications

Enabled by mobile and wearable technology, personal health data delivers immense and increasing value for healthcare, benefiting both care providers and medical research. The secure and convenient sharing of personal health data is crucial to the improvement of the interaction and collaboration of the healthcare industry. Faced with the potential privacy issues and vulnerabilities existing in current personal health data storage and sharing systems, as well as the blockchain integration concerns summarized in this paper, an innovative user-centric health data sharing solution by utilizing a decentralized but permissioned blockchain is proposed to protect privacy and enhance access management, with the …

Nox Formation In Syngas/Air Combustion, Nazli Asgari

Theses and Dissertations

Syngas is a reliable energy source derived from the gasification of coal and other solid fuels. The feedstock type and the production process of syngas can affect the composition of syngas. Gas turbines utilizing high hydrogen content (HHC) fuels like syngas for power generation applications need to meet stringent pollutant emission standards, particularly with respect to nitrogen oxides (NOx). For gas turbine conditions, reliable experimental data, especially at high-pressure, is necessary for both generating accurate NOx prediction models and improving reaction pathways regarding the NOx chemistry. In this study, NOx formation in post-flame gases of syngas combustion at different conditions …

Hydrothermal Carbonization Of Food Waste For Nutrient Recovery And Reuse, Ifeolu M. Idowu

Theses and Dissertations

Food waste represents a rather large and currently underutilized source of potentially available and reusable nutrients. Laboratory-scale experiments evaluating the hydrothermal carbonization of food wastes collected from restaurants were conducted to understand how changes in feedstock composition and carbonization process conditions influence primary and secondary nutrient fate. Results from this work indicate that at all evaluated reaction times and temperatures, the majority of nitrogen, calcium, and magnesium remain integrated within the solid-phase, while the majority of potassium and sodium reside in the liquid-phase. The fate of phosphorus is dependent on reaction times and temperatures, with solid-phase integration increasing with higher …

Social Engineering Knowledge Measured As A Security Countermeasure, Christopher Artejus Sanders

Theses and Dissertations

Social Engineering has become a significant threat to the security of business, government, and academic institutions. As vulnerabilities to social engineering attacks increase, organizations must incorporate risk mitigation strategies to their portfolios of Information Systems Security Countermeasures (ISSC). The goal is to implement mitigation strategies that balance the cost of implementation, the privacy of employees, and the resulting expected costs of social engineering attacks. In this paper we develop an analytical model that calculates the total cost of protection, including the trade-off between the cost of implementing protection strategies and the resulting expected cost of social engineering attacks. We use …

Ontology-Guided Pre-Release Inference Disruption, Mark Stephen Daniels

Theses and Dissertations

We investigate privacy violations occurring when non-confidential patient data is combined with medical domain ontologies to disclose a patient’s protected health information (PHI). We propose a framework that detects privacy violations and eliminates undesired inferences. Our inference channel removal process is based on controlling the release of the data items that lead to undesired inferences. These data items are either blocked from release or generalized to eliminate the disclosure of the PHI. We show that our method is sound and complete. Soundness means the only inference paths generated logically follow from released data and corresponding domain knowledge. Completeness means we …

Development Of Bimetallic Catalysts For Dry Reforming Of Methane And Hydrogenation Of Succinic Acid, Jayson Michael Keels

Theses and Dissertations

Advances in natural gas recovery have greatly impacted the global economy; the abundant supply of gas has revealed new opportunities and challenges in a wide range of markets within the fuels and chemicals industries. One such opportunity exists with the overabundance of gas from remote wells that is flared or emitted because of the high costs associated with transportation of a chemical with such a high molar volume. A possible solution is an on-site process to convert gas to higher value chemicals that are liquid at standard conditions, and can more easily be transported. As a first step, CO2 from …

The Visual Ecology Of Speyeria Mormonia, Natalie Sanchez Gonzalez

Theses and Dissertations

Variations in environmental factors such as temperature, precipitation, and day length during larval development are known to affect morphological traits in butterflies related to their visual ecology, including eye size and wing color. These vision-related traits are important for the ability of diurnal butterfly species to detect mates, especially at long distances. Thus, changes in environmental conditions may result in phenotypic modifications to butterflies which may alter their visual ecology and subsequently, their reproductive fitness. To study the interaction of phenotypic plasticity and visual ecology in the Mormon Fritillary, Speyeria mormonia, I set up a natural-laboratory experiment at the Rocky …

High Resolution Radiation Detectors Based On 4h-Sic N-Type Epitaxial Layers And Pixilated Cdznte Single Crystal Devices, Cihan Oner

Theses and Dissertations

Silicon Carbide (SiC) is an indirect wide bandgap semiconductor with high thermal conductivity, high breakdown electric field, high carrier saturation drift velocity, and large displacement energy making it a suitable candidate for replacing conventional radiation detectors based on Si, Ge, CdTe, and CdZnTe (CZT). In this dissertation, fabrication and characterization of high-resolution Schottky barrier detectors for alpha particles using 20 µm thick n-type 4H-SiC epitaxial layers are reported. Schottky barriers were obtained by depositing circular nickel contacts of ~10 mm2 area.

Room temperature current-voltage (I-V) measurements revealed Schottky barrier heights of the order of 1.7 eV, ideality factor of ~1.1, …

Understanding Geopolymerization Process For Enhancement Of Mechanical Properties Of Fly Ash Based-Geopolymer Concrete, Lateef Najeh Assi

Theses and Dissertations

Concrete is a major construction material that is largely made up of cement. Unfortunately, the manufacturing process for the cement currently used to produce concrete releases a great deal of CO2, which endangers the environment. Hence, finding alternatives to ordinary Portland cement is of extreme importance. The intellectual contribution of this dissertation is the development of an improved understanding of the geopolymerization process so that the compressive strength of cement can be maximized while the need for external heating is minimized. The intent is to create a substance to replace commonly used cement without sacrificing other beneficial properties. The first …

Take-Off Characteristics For Naca 4612 Aerofoil In A Twin-Wing Configuration With Optimum Angles Of Attack, Elena Vishnevskaya, Kenneth L. Witcher, Ian R. Mcandrew

Publications

Unmanned Aerial Vehicles are used generally at low levels and speeds. The research reported in this article investigates the possible use of twin-wing designs for higher altitudes with a focus on the possible lift capable for either short runways or high payloads. The wing aerofoil and unique Angles of Attack, AoA, are set 5o on the upper wing and 10o on the lower. There is a positive upper wing stagger of 50% of the chord length at height separation of 1 chord. These parameters have been established from previous research and this research investigates how they generate lift at take-off …

Effects Of Air And Other Gases In The Stabilization Process Of The Superprotonic Phase Of Cesium Dihydrogen Phosphate Within A Hermetically Sealed Chamber, Israel Martinez

Open Access Theses & Dissertations

The solid acid CsH2PO4 (CDP), exhibits a sudden increase in its proton conductivity as it’s heated above a certain temperature (around T~235oC), which makes it a very attractive candidate to be used as an electrolyte in intermediate temperature fuel cells. Unfortunately, at these temperatures the sample is not stable, as starts to dehydrate; which causes a dramatic drop in the proton conductivity over a short period of time (less than one hour). In order to inhibit, or at least delay, the dehydration process, the solid acid it’s put under a saturated water vapor atmosphere. Another method to stabilize the highly …

Super-Resolution In The Presence Of Atmospheric Optical Turbulence, Russell C. Hardie, Michael A. Rucci, Barry K. Karch, Alex J. Dapore, Douglas R. Droege

Electrical and Computer Engineering Faculty Publications

The design of imaging systems involves navigating a complex trade space. As a result, many imaging systems employ focal plane arrays with a detector pitch that is insufficient to meet the Nyquist sampling criterion under diffraction-limited imaging conditions. This undersampling may result in aliasing artifacts and prevent the imaging system from achieving the full resolution afforded by the optics. Another potential source of image degradation, especially for long-range imaging, is atmospheric optical turbulence. Optical turbulence gives rise to spatially and temporally varying image blur and warping from fluctuations in the index of refraction along with optical path. Under heavy turbulence, …

Advanced Ion Management To Improve Oil Recovery In Oil-Wet Carbonate-Sandstone Composite Reservoirs, Ali K. Alhuraishawy, Baojun Bai, Mingzhen Wei, Waleed H. Al-Bazzaz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Waterflooding with different ionic composition called advanced ion management which play a role with ionic composition of injected water to enhance the oil production. In the last decade, many studies pointed out that the composition of injected water could changes rock wettability during waterflooding. The main purpose of this study is to evaluate the effects of SO4 and low salinity water on improving oil recovery in oil-wet carbonate reservoirs. Sulfate ion concentration, low salinity water, rock composition, porosity, and permeability were examined using a designed model. Typical seawater, increase SO₄, two and three times in the seawater, and …

Sustainable Living Factories For Next Generation Manufacturing, Yoram Koren, Xi Gu, Fazleena Badurdeen, Ibrahim S. Jawahir

Mechanical Engineering Faculty Publications

To be profitable and to generate sustainable value for all stakeholders, next generation manufacturers must develop capabilities to rapidly and economically respond to changing market needs while at the same time minimizing adverse impacts on the environment and benefiting society. 6R-based (Reduce, Reuse, Recycle, Recover, Redesign and Remanufacturing) sustainable manufacturing practices enable closed-loop and multi-life cycle material flow; they facilitate producing more sustainable products using manufacturing processes and systems that are more sustainable. Reconfigurable Manufacturing Systems (RMS) and its characteristics of scalability, convertibility, diagnosability, customization, modularity and integrability have emerged as a basis for living factories for next generation manufacturing …

Towards Developing Sustainable Reconfigurable Manufacturing Systems, Aihua Huang, Fazleena Badurdeen, Ibrahim S. Jawahir

Mechanical Engineering Faculty Publications

This paper aims to examine the sustainable manufacturing performance of Reconfigurable Manufacturing Systems (RMSs) using existing sustainable manufacturing metrics. RMS has six key characteristics including modularity, integrability, customization, scalability, convertibility, and diagnosability. In this paper, ‘convertibility’ is quantified by considering configuration convertibility, machine convertibility, and material handling device convertibility from the RMS perspective. In addition, the performance of RMSs with different convertibility levels is also evaluated by using sustainable manufacturing metrics. A numerical example is used to demonstrate the computational approach. Results of the analysis are used to show how sustainable manufacturing performance of RMS changes as system convertibility varies. …