Digital Commons Network^™

Nonupdating Methods For The Characterization Of Nonlinear Stress-Strain And Delamination Fracture Properties Of Fiber Reinforced Composites, Bastiaan Corstiaan Van Der Vossen

Mechanical and Aerospace Engineering Dissertations - Archive

Efforts to develop strength and life prediction analysis tools for aircraft composite structures have shown a great need to understand the complexity and interaction of failure modes. Many failure models are highly sensitive to transverse nonlinear shear stress-strain and delamination fracture properties, which are notoriously hard to measure. Without proper input parameters, life predictions analyses will not be successful. The objective of this work was to accurately characterize these mechanical properties of carbon fiber reinforced polymer composites through advanced experimental methods. Full-field noncontact deformation measurements using Digital Image Correlation are used to quantify all surface strains components, enabling the design …

Design Principles For Large Foil Bearings Based On Scaling Laws: Analyses And Experiment, Srikanth Honavara Prasad

Mechanical and Aerospace Engineering Dissertations - Archive

Gas foil bearings are used for supporting high speed turbomachinery systems. They are characterized by complex physical and thermal interactions between the lubricating fluid and the structural elements. Mathematically, the behavior of such systems is governed by nonlinear partial differential equations and pose substantial computational challenges. However, their potential applications in aerospace systems and power generation systems have renewed research and development efforts aimed at simplifying their design and analyses methods. Commercialization of gas foil bearings in Mega Watt scale applications necessitate the development of simple tools for estimating bearing design parameters such as load capacity, radial clearance, and support …

Performance Modeling And Experimental Investigations Of Rotating Detonation Engines, Andrew Ryan Mizener

Mechanical and Aerospace Engineering Dissertations - Archive

The rotating detonation engine (RDE) is a promising propulsion concept that has the potential to offer increased thermodynamic performance in a compact package with no moving parts. A series of analytical and experimental investigations was carried out on RDEs with the joint goal of investigating swirl, torque, and a range of other design parameters of interest. The model and experimental facility were then applied to related problems with the goal of advancing the understanding of RDE applications. A flexible, low-order, semi-empirical model for a rotating detonation engine was presented. The model was formulated to be able to run broad parametric …

Direct Numerical Simulation Of Homogeneous Isotropic Turbulence - A Methodology And Applications, Sarah Moussa Hussein

Mechanical and Aerospace Engineering Dissertations - Archive

Turbulence has been a topic of scientific research for years. Characterized by unorganized chaotic motion and irregular fluctuations, it persists as one of the most challenging topics in fluid mechanics despite volumes of documented research and crucial findings. This begs the question: What is turbulence and why is it so challenging? Turbulence research studies cover a wide spectrum of branches from fundamental flow propagation to different turbulence interactions. This research project investigates the simplest class of turbulent flow studies, homogeneous isotropic turbulence. In a quest to advance the fundamental understanding of turbulence physics, a direct numerical simulation tool is developed. …

Reachable Set Computation And Analysis For Perturbed Linear Systems, Prabhjeet Singh Arora

Mechanical and Aerospace Engineering Theses - Archive

Determination of the set of all possible states, which a system can attain, plays an important role in safety for critical application. Prior knowledge of this set for the complete run-time provides critical information about how a system may evolve, providing accurate information of all the states, which could violate constraints. The knowledge of these states, helps in estimating control input, which can control the system, such that, these states are eliminated from the reachable set. Computation of reachable set of a dynamic system for a set of initial conditions can be easily performed, provided the analytical solution of the …

An Analytical Design Of Experiments Method For Fatigue Constrained Design Optimization Of A 3d Printed Structure, Ashish Pokharel

Mechanical and Aerospace Engineering Theses - Archive

A design of experiments approach has been used to analytically determine a low cycle fatigue (LCF) constraint for use in design optimization of 3D printed structures. In context of metal additive manufacturing, the process of melting, solidification and consolidation of metal powder introduces very high temperature gradient field within the build which in turn results in high compressive stresses at the core and tensile stresses at the outer surface of the part after it has cooled down to room temperature post build. An approach of finite element modeling in ANSYS Additive has been used to develop a residual stress profile …

Enhancing Tensile Strength Of Fdm Parts Using Thermal Annealing And Uniaxial Pressure, Rhugdhrivya Rane

Mechanical and Aerospace Engineering Theses - Archive

Additive manufacturing has been a revolutionary and disruptive technological development in the field of design and manufacturing with Fused deposition modelling (FDM) being at the forefront of this technology. But it is seen that parts printed using FDM suffer from an inherent deficiency of weak tensile strength in the out of plane direction (z-direction) thus limiting their application. This issue of weak z-direction strength is due to the weak Inter-bead bond strength of adjacent polymer interfaces. The purpose of this work is to increase this Inter-Bead bond strength thus increasing the overall tensile strength of the part. In this work, …

The Economic Impact Of Refugees On A Host Country, Zaid Ghaleb-Sharari-Al-Bakhit Alfayez

Public Affairs Dissertations - Archive

Refugee numbers are increasing around the world due to political instability. Host countries are encountering several issues such as socioeconomic challenges as a result of refugees. Therefore, it is essential to investigate the effects of the economic impact of refugees. The Middle East region has taken in a high number of these refugees, especially Jordan. This empirical research studies the impact for countries receiving refugees to help policy makers effectively regulate and deal with this challenge. This study analyzes the impact of refugees on the economy using Jordan as a case study. However, this research can be applied to other …

Teacher Perceptions Of School Culture After The Change From A Semester Schedule To A Trimester Schedule: A Phenomenological Study, Joseph Showell

Educational Leadership & Policy Studies Dissertations - Archive

Principals newly assigned to a campus often begin their work by talking with staff, reviewing data, and evaluating the organizational structure with which they were entrusted (Daresh & Alexander, 2015). Common areas for review include campus budget, student performance on state and federal testing, overall operating systems such as the school bell schedule, school culture, and campus operating systems for communication (Daresh & Alexander, 2015). From this review, principals design action plans that they believe best fit the needs of the campus. The effectiveness of the principals’ action plans generally is based on quantitative student performance data from state and …

The Monadnock Volume 60, December 2018, Clark University Geographical Society

The Monadnock (Clark Geographical Society)

Volume 60 of The Monadnock. The Monadnock was the alumni magazine of the Clark University Geographical Society (1927-1985) (2014-present).

Epidemiological Evidence And Health Risks Associated With Agricultural Reuse Of Partially Treated And Untreated Wastewater: A Review, Anthony A. Adegoke, Isaac D. Amoah, Thor A. Stenström, Matthew E. Verbyla, James R. Mihelcic

Civil and Environmental Engineering Faculty Publications

The use of partially treated and untreated wastewater for irrigation is beneficial in agriculture but may be associated with human health risks. Reports from different locations globally have linked microbial outbreaks with agricultural reuse of wastewater. This article reviews the epidemiological evidence and health risks associated with this practice, aiming toward evidence-based conclusions. Exposure pathways that were addressed in this review included those relevant to agricultural workers and their families, consumers of crops, and residents close to areas irrigated with wastewater (partially treated or untreated). A meta-analysis gave an overall odds ratio of 1.65 (95% CI: 1.31, 2.06) for diarrheal …

The Making Of An Engineer: Examining The Planning Process And Educational Outcomes, Richard L. Raleigh

Educational Leadership & Policy Studies Dissertations - Archive

This quantitative study uses data from the Educational Longitudinal Study of 2002 (ELS: 2002) to examine how aspiration levels of planning (or intention) and action (or choice) affect degree attainment for college students who expressed interest in pursing an engineering degree. Utilizing Social Cognitive Career Theory as derived from Bandura's (1986) social cognitive theory, I investigated whether students' self-efficacy along with personal aspects of motivation and their aspirations influence educational attainment outcomes. These attributes are indicative of future intentions, and essential in students' persistence to overcome barriers toward completing an engineering degree. Data analysis includes descriptive statistics to compare Aspiring-engineers …

Principal Leaders And College And Career Readiness Programs, Inna Goretaya Polishchuk

Boise State University Theses and Dissertations

This dissertation examines the intersection of high school principals and college and career readiness initiatives in five high school contexts. Because school principals are responsible for setting the vision in a school, college and career readiness initiatives have the potential to overlap significantly with the principal’s direction of the school. Moreover, studies indicate college and career readiness programs might rely on the active support of the school administrator if they are to succeed. What the school leader cares about tends to be what staff focus on; therefore, this study examines how three factors influence the effectiveness of a college and …

Injecting Control Commands Through Sensory Channel: Attack And Defense, Farhad Rasapour

Boise State University Theses and Dissertations

Industrial Control System (ICS) is responsible for controlling and managing critical infrastructures like nuclear plants and power plants. ICS is equipped with various devices like communication media, Programmable Logic Controller (PLC), actuators, and sensors. Sensors are used to measure a physical phenomenon and send these measurements through the sensory channel to the control devices so they can make decisions on the movements of the actuators in the systems. While tampering with the sensor measurements has been the focus of many studies, there is some research that has concentrated on misusing a sensor and sensory channel as an axillary attack device …

Effect Of Subsurface Conditions On Flexible Pavement Behavior: Non-Destructive Testing And Mechanistic Analysis, Md. Fazle Rabbi

Boise State University Theses and Dissertations

The behavior of flexible pavements under traffic and environmental loading can be significantly affected by subsurface conditions. Inadequate support conditions under the surface can lead to excessive pavement deformations, often leading to structural and functional failure. This research effort focused on assessing the effects of base/subbase and subgrade layer conditions on flexible pavement behavior. The results of this study are presented in the form of two journal manuscripts.

The first manuscript focuses on utilizing pavement structural and functional evaluation data in making pavement rehabilitation decisions. Visual distress surveys and Falling Weight Deflectometer (FWD) testing are often carried out by agencies …

Local Peer-To-Peer Communication To Improve Demand Response In Residential Neighborhoods, Ryan Schwartz

Boise State University Theses and Dissertations

Increased electricity production from intermittent renewables presents a challenge to utilities. Since the grid has little ability to store energy, fluctuations in solar and wind generation require either an increase in generation from expensive sources or a reduction of demand. Demand Response (DR) programs focus on the latter and are designed to increase grid flexibility by allowing grid operators to modify when or how customers use electricity. For residential customers, this typically means shedding load during periods of high demand through a central controller temporarily shutting off air conditioning (AC) compressors. This type of DR can cause spikes in demand …

The Pre-Positioned Warehouse Location Selection For International Humanitarian Relief Logistics, Sae Yeon Roh, Young Ran Shin, Young Joon Seo

Plymouth Business School

© 2018 This study aims to identify the most appropriate pre-positioned warehouse location for international humanitarian relief organisations. A two-step methodology is structured using fuzzy AHP and fuzzy TOPSIS to evaluate pre-positioned warehouse locations for humanitarian relief organisations. The empirical case study analysis of a humanitarian relief organisation is conducted to illustrate the use of the proposed framework for ranking alternative locations. This framework provides a more accurate, effective, and systematic decision support tool for stepwise implementation of warehouse location selection in humanitarian relief operations to increase efficiency. National stability is considered the most crucial factor for warehouse selection followed …

Single Sourcing Versus Multisourcing: The Roles Of Output Verifiability On Task Modularity, Shantanu Bhattacharya, Alok Gupta, Sameer Hasija

Research Collection Lee Kong Chian School Of Business

This paper compares two modes for outsourcing the development of information services projects: single-sourcing (where one vendor handles all outsourced activities) and multisourcing (where multiple vendors handle those activities). We assess the relative efficacy of these two outsourcing modes by identifying the effects of three factors: task modularity, the extent of alignment between a (verifiable) performance metric and project revenue, and the extent to which project revenue is itself verifiable. We find that if tasks are modular then multisourcing strictly dominates single-sourcing—provided the verifiable performance metric and project revenue are not completely aligned. Yet if tasks are integrated, then the …

Development And Validation Of Hybrid Continuum/Structural Finite Element Model For Evaluating Foot And Ankle Biomechanics, Saif Alrafeek

Dissertations

Bone is composed of two structures: compact bone and spongy bone. Spongy bone porosity highly affects the strength and the physical endurance of bone to carry loads. Most studies use continuum finite element (FE) approaches to model spongy bone and neglect porosity. Neglecting porosity may not efficiently assist orthopaedic surgeons to treat patients who experience bone physical disability. The purpose of this study is to demonstrate an inexpensive approach that simulates spongy bone with more accurate capturing of porosity and less requirements of bone information. The approach is developed through investigating the mechanical characteristics of spongy bone; that is, by …

Retinex-Based Visibility Enhancement System For Inclement Weather With Tracking And Distance Estimation Capabilities, Marwan S. Alluhaidan

Dissertations

Road conditions affected by weather are well known to have an impact on the number of vehicle accidents and fatalities, due to low- to no-visibility conditions. According to the U.S. Department of Transportation, there are more than 1,259,000 crashes each year. On average, 6,000 people are killed and more than 445,000 people are injured annually due to severe weather conditions. These accidents could be significantly reduced if real-time visibility enhancement systems were made available. However, eliminating the impact of weather conditions on visibility is still lacking and beyond our control. The time has come to develop technology that is capable …

Radiative Double Electron Capture (Rdec) By Fully-Stripped Fluorine Ions In Collisions With Nitrogen, Nuwan Sisira Kumara

Dissertations

Radiative double electron capture (RDEC) by highly-stripped ions in collisions with atomic targets is a fundamental process that can be used to study electron-electron correlation, the interaction between two electrons, in the vicinity of the Coulomb field of a bare ion. In this process two electrons from the target are captured to bound states of the projectile with the simultaneous emission of a single photon. RDEC is closely related to the well-known one-step atomic process of radiative electron capture (REC), in which a target electron is captured to the projectile and a photon is simultaneously emitted. REC and RDEC can …

A Simple Proximal Stochastic Gradient Method For Nonsmooth Nonconvex Optimization, Zhize Li, Jian Li

Research Collection School Of Computing and Information Systems

We analyze stochastic gradient algorithms for optimizing nonconvex, nonsmooth finite-sum problems. In particular, the objective function is given by the summation of a differentiable (possibly nonconvex) component, together with a possibly non-differentiable but convex component. We propose a proximal stochastic gradient algorithm based on variance reduction, called ProxSVRG+. Our main contribution lies in the analysis of ProxSVRG+. It recovers several existing convergence results and improves/generalizes them (in terms of the number of stochastic gradient oracle calls and proximal oracle calls). In particular, ProxSVRG+ generalizes the best results given by the SCSG algorithm, recently proposed by [Lei et al., NIPS'17] for …

Comparison Mining From Text, Maksim Tkachenko

Dissertations and Theses Collection (Open Access)

Online product reviews are important factors of consumers' purchase decisions. They invade more and more spheres of our life, we have reviews on books, electronics, groceries, entertainments, restaurants, travel experiences, etc. More than 90 percent of consumers read online reviews before they purchase products as reported by various consumers surveys. This observation suggests that product review information enhances consumer experience and helps them to make better-informed purchase decisions. There is an enormous amount of online reviews posted on e-commerce platforms, such as Amazon, Apple, Yelp, TripAdvisor. They vary in information and may be written with different experiences and preferences.

If …

Empathetic Computing For Inclusive Application Design, Kenny Choo Tsu Wei

Dissertations and Theses Collection (Open Access)

The explosive growth of the ecosystem of personal and ambient computing de- vices coupled with the proliferation of high-speed connectivity has enabled ex- tremely powerful and varied mobile computing applications that are used every- where. While such applications have tremendous potential to improve the lives of impaired users, most mobile applications have impoverished designs to be inclusive– lacking support for users with specific disabilities. Mobile app designers today haveinadequate support to design existing classes of apps to support users with specific disabilities, and more so, lack the support to design apps that specifically target these users. One way to resolve …

A Note On Algebraic Structures, Kuncham Syam Prasad

Manipal Journal of Science and Technology

In this paper, we introduce the idea of 2-Banach algebra and 2-C*-algebra with suitable examples and some related results are established. We provide the recent developments and related results in near-algebra. We also give a generalization of gamma nearring and a module over a gamma nearring with suitable illustration.

Mb4t (Mathematics By And For Teachers): Supporting Understanding Of Fraction Operations, Jennifer Holm

Education Faculty Publications

No abstract provided.

Building A Versatile Deduplication System, Zhichao Yan

Computer Science and Engineering Dissertations - Archive

With the development of the Internet and information technology, a large amount of unstructured data is generated and stored in various storage systems. In particular, data reduction techniques such as compression and deduplication have become an effective way to address the combined challenges of explosive growth in data volume but lagging network bandwidth growth to increase the space and bandwidth efficiency of various storage systems. However, we have found that existing deduplication systems cannot effectively process compressed data and image data because existing deduplication systems only analyze the hash value of the bitstream to detect redundant data. At the same …

Use Of Rubric In Assessment To Support Learning, Dennis Odhiambo Ogollah

Master of Education

The study involved an intervention on use of rubrics in assessment with an aim of empowering teachers and students with skills and knowledge that would facilitate implementation of assessment for learning strategies to promote student engagement in learning. This was conducted by adopting quasi experimental design and quantitative approach that involved administering of pretest and posttest to the treatment and control group and the results analyzed using t-test analysis to establish the effect of intervention. A total of 40 students from two form three classes that formed treatment and control group by random selection, participated in the research, with control …

Critical Search: A Procedure For Guided Reading In Large-Scale Textual Corpora, Jo Guldi

History Faculty Publications

Q: What happens when the good, old-fashioned virtues of Liberal Arts education, e.g. "Critical Thinking," enter the age of big data?

A: We teach "Critical Search," a model process for approaching big data research. Critical Search models a way of engaging humanities question, textuality, secondary literature, data, and tools. It is suitable to both the statistician who wishes to make meaning from the past as well as the traditional humanist who browses library catalogs through keywords.

This article presents the concept of "critical search" and offers an exposition of its application to a search for the history of eviction in …

Young Women In Stem: An Analysis Of Outreach Programs For Middle School Girls, Rachel Lundeen

Honors Projects

Historically, and still presently, women face many obstacles when attempting to pursue science, technology, engineering, and math (STEM) fields. Women have been systematically barred from entering STEM programs at universities and today face cultural obstacles, resulting in marginalization. Research points to adolescence as the age where this sense of marginalization begins to develop. As a result, many outreach programs for young women interested in STEM are targeted toward the middle school age group. This study adds to this research by examining two such outreach programs for young women in STEM to determine their effectiveness, including Camp GEMS at Ohio Northern …