Engineering Commons^™

Numerical Modeling Of Phase Transition In Shock Tube Problem, Man Minh Le

Theses and Dissertations

In this work, we developed a numerical model for phase transition in shock-tube problem. This work focused on simulating shock-tube problem and the numerical framework is based on a two-phase flow model. Our simulation tool is an in-house FORTRAN multiphase compressible flow solver, RocSDT [31]. Specifically, this involves the Euler equations along with the Stiffened Gas Equation of State (EOS), an interface of liquid-gas type, and the effects of heat and mass transfer due to phase transition. This thesis described the implementation and incorporation of a phase transition model into a system of five partial differential equation model and the …

The Effects Of Stress Relieving Heat Treatment On The Microstructure And Residual Stress Of Inconel 718 Fabricated By Laser Metal Powder Bed Fusion Additive Manufacturing Process, Xiaoqing Wang, Kevin Chou

Research, Publications & Creative Work

In this study, the microstructure and residual stress of the Inconel 718 parts, which were fabricated by laser metal powder bed fusion additive manufacturing process, in as-fabricated and stress-relieved conditions were investigated by metallographic analysis and microhardness test. Fine equiaxed and columnar cellular dendrites were revealed in the Transverse plane, Frontal plane, and Sagittal plane, respectively. Laves phases were found in the interdendritic regions and interlayers. After the stress relief heat treatment, the Laves phases has partly solved into the γ matrix and the microstructure became relatively homogeneous, which leads to the significant increase (~19%) in the microhardness. Residual stress …

On-Site Design Of A Water Filtration System In Rural Ghana, Donald Eugene Long

Construction Management

Agbokpa is a rural community in southern Ghana with no access to clean or running water. Villages without access to water face significant hurdles in obtaining an education and developing their communities’ infrastructure and economy. In August of 2019 Cal Poly students Eugene Long, Fletcher Podosek, and Mason Nolan traveled with professors Paul Redden and Dr. Nathan Heston to Agbokpa to fix this problem. The team spent three weeks living in the village and constructing a water tower, pumping system, and filtration system that communally serves the village. The team worked with local craftsmen and sourced nearly all equipment and …

Implementing Ti Construction Into Cal Poly's Construction Management Curriculum, Ryan Donald Strong

Construction Management

No abstract provided.

Numerical Treatment Of Schrödinger’S Equation For One-Particle And Two-Particle Systems Using Matrix Method, Spatika Dasharati Iyengar

Doctoral Dissertations and Master's Theses

With an increased interest in accurately predicting aerothermal environments for planetary entry, recent researches have concentrated on developing high fidelity computational models using quantum-mechanical first principles. These calculations are dependent on solving the Schrödinger equation using molecular orbital theory techniques. They are either approximate solutions to actual equations or exact solutions to approximate equations. Exact solutions have not found favor due to the computational expense of the problem. Hence, a novel numerical approach is developed and tested here using linear algebraic matrix methods to enable precise solutions.

The finite-difference technique is used to cast the Time-Independent Schrödinger equation (TISE) in …

Feasibility Analysis Of Adipic Acid Production, Serpil Unlu

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Adipic acid is an essential intermediate chemical feedstock for the production of nylon-6,6; hence it is valuable from an industrial perspective. Currently, commercial adipic acid production includes a combination of two stages. The first stage produces a mixture of cyclohexanone and cyclohexanol called ‘’KA oil” derived from cyclohexane. In the second stage, KA oil is reacted with nitric acid to produce adipic acid. The second stage generates excess N₂O emission, which is considered as 310 times more potent than CO₂. Renewable feedstocks that can be converted to value-added chemicals offer significant potential for the necessary transition …

Development Of A Mix Design Adjustment Method For Fiber Reinforced Concrete And Super High Performance Concrete Based On Excess Paste, Joe Malloy

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The main objective of this study was to develop a mix design adjustment method for Fiber Reinforced Concrete (FRC) that would maintain appropriate workability while improving hardened concrete performance. A literature review was conducted to examine existing methods for adjusting mix designs to account for fiber introduction. It was found that while increasing fine aggregate and cement paste content can make up for lost workability with the addition of fibers, no rational mix design adjustment method is available. Reference mix designs from the Nevada Department of Transportation and the Nebraska Department of Transportation were used, and this study focused on …

Nanothermomechanical Logic Gates For Thermal Computing, Ahmed Hamed

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications require the development of alternative computing technologies. Thermal computing, data processing based on heat instead of electricity, is proposed as a practical alternative and opens a new scientific area at the interface between thermal and computational sciences.

We successfully developed thermal AND, OR and NOT logic gates, achieved through the coupling between near-field thermal radiation and MEMS thermal actuation. In the process, we developed two novel non-linear thermal …

Magnetic Properties Of Nd–Fe–B Permanent Magnets Under Thermal Experimentation, Géraldine Houis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Neodymium-Iron-Boron (Nd-Fe-B) magnets were developed in the 1980s, and since then, they have appeared as a common component in many fields. From the industry to consumers or defense applications, from turbines, computers, cellphones to most audio systems, Nd-Fe-B magnets are present everywhere. But when Nd-Fe-B magnets are applied to the motors of electric vehicles and wind-turbine generators, their temperature rises, therefore Nd-Fe-B-Dy magnets are used. However, while the use of these magnets is common at low temperatures, their properties decrease dramatically with the increase of temperature. In this paper, the Nd-Fe-B-based samples used were prepared by using arc melting, melt …

Extending Mission Duration Of Uas Multicopters: Multi-Disciplinary Approach, Marc Lussier

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Multicopters are important tools in industry, the military, and research but suffer from short flight times and mission durations. In this thesis, we discuss three different ways to increase flight times and therefore increase the viability of using multicopters in a variety of missions. Alternate fuel sources such as hydrogen fuel and solar cells are starting to be used on multicopters, in our research we simulate modern fuel cells and show how well they currently work as the power source for multicopters and how close they are to becoming useful in Unmanned Aircraft System (UAS) technology. Increasing the efficiency in …

Development Of Forward Osmosis Based Separations: A Novel Approach In Membrane Technology, Yu-Hsuan Chiao

Graduate Theses and Dissertations

Tackling the worldwide severe water shortage, the membrane technology is considered to be the most efficient approach and hence, used widely as a cost-effective sustainable solution. “Forward osmosis (FO)” has been the major attention in recent time. FO uses osmotic pressure as the driving force to draw the water passing the membrane and achieve the desired separation performance. In general, it is considered to be a process with tremendous potential to resolve the present-day water shortage with extremely low energy consumption. However, the challenges of membrane and draw solution regeneration associated with FO processes must be conquered prior to their …

Of Promoting Networking And Protecting Privacy: Effects Of Defaults And Regulatory Focus On Social Media Users’ Preference Settings, Hichang Cho, Sungjong Roh, Byungho Park

Research Collection Lee Kong Chian School Of Business

Privacyresearch has debated whether privacy decision-making is determined by users'stable preferences (i.e., individual traits), privacy calculus (i.e.,cost-benefit analysis), or “responses on the spot” that vary across contexts.This study focuses on two factors—default setting as a contextual factor andregulatory focus as an individual difference factor—and examines the degree towhich these factors affect social media users' decisionmaking when usingprivacy preference settings in a fictitious social networking site. Theresults, based on two experimental studies (study 1, n = 414; study 2, n =213), show that default settings significantly affect users' privacypreferences, such that users choose the defaults or alternatives proximal tothem. Study 2 …

Career Prospects And Resources Of Domestic Engineering Doctoral Students, Laura A. Gelles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Career prospects are a motivating factor for entry and retention of doctoral students, especially in the discipline of engineering. While doctoral student training provides them with highly specialized skills to be an independent researcher, they may not have the requisite skills or guidance to secure the job position of their choice. Therefore, it is important to provide doctoral students with opportunities, training, and information (i.e., resources) about different types of careers to not only ensure they are productive contributors of teaching and research, but also equip them for future career prospects. Research techniques based upon in-depth narrative interviews and combining …

A New Approach For Evaluating The Ductility, Volumetric Stiffness, And Permeability Of Cutoff Wall Backfill Materials, Jennifer Ostrowsky

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The use of plastic concrete for cutoff walls in dams for remediation of seepage issues has become more widely used in the past 25 years, however, the in-situ material properties are still not well understood. The research presents a new testing procedure that combines two existing testing methods, triaxial shear and permeability testing. By developing this laboratory testing method, material properties of the cutoff wall backfill material can be more accurately examined and explained using changes in the permeability of the material to discern the ductility and stiffness.

Mitigating The Risk Of Bird Strikes: The Use Of Virtual Reality During Flight Training, Flavio A. C. Mendonca Ph.D., Julius Keller Ph.D., Chien-Tsung Lu, Chenyu Huang Ph.D.

Publications

There were 193,969 wildlife strikes in the US from 1990 through 2017. Wildlife strikes annually cost the US civil aviation industry, on average, $186 million in monetary losses and 111,284 hours of aircraft downtime (Dolbeer & Begier, 2019). According to the Federal Aviation Administration (FAA), Aeronautical Decision-Making (ADM) is a systematic approach that encourages pilots to identify hazards and manage risks (FAA, 2016). Additionally, it helps aviators to make timely and safe decisions. Even though it is practically impossible to eliminate the risk of bird strikes, crewmembers play a vital role in the accident prevention process (Mendonca, Carney, & Fanjoy, …

Hydrodynamic Ram Analysis Of Bonded Composite Fuel Tanks, Teddy Sedalor

Theses and Dissertations

Military aircraft are tested against a variety of ballistics threats as part of their design to assess their vulnerability. One aspect of this approach/requirement is Hydrodynamic Ram testing which accounts for projectile impact into fuel tanks. Hydrodynamic Ram (HRAM), which occurs due to overpressure created in an enclosed fluid as a result of the transfer of energy and momentum from a penetrating projectile, can be quite destructive to the enclosing structure, which makes testing expensive. Therefore the need arises for numerical methods to supplement the testing and provide more test data than can be obtained directly from the article test. …

Green Up Pavement Rehabilitation Design Tool, Dragos Andrei, Robert E. Kochan, Jose H. Perez

Mineta Transportation Institute

While designers produce pavement rehabilitation recommendations every day, for projects of all sizes, most designers have little information on the environmental impact of their recommendations. This research developed a new decision tool, called the “Green Up Pavement Rehabilitation Design Tool,” to allow the comparison of different rehabilitation solutions in terms of greenhouse gas emissions and to encourage sustainable practices such as materials recycling and the use of permeable, cool, and quiet pavement surfaces. The project aligns with the major goal of California Senate Bill 1, which is “to address deferred maintenance on the state highway system and the local street …

Automated Measurement Of Heavy Equipment Greenhouse Gas Emission: The Case Of Road/Bridge Construction And Maintenance, Reza Akhavian

Mineta Transportation Institute

Road/bridge construction and maintenance projects are major contributors to greenhouse gas (GHG) emissions such as carbon dioxide (CO2), mainly due to extensive use of heavy-duty diesel construction equipment and large-scale earthworks and earthmoving operations. Heavy equipment is a costly resource and its underutilization could result in significant budget overruns. A practical way to cut emissions is to reduce the time equipment spends doing non-value-added activities and/or idling. Recent research into the monitoring of automated equipment using sensors and Internet-of-Things (IoT) frameworks have leveraged machine learning algorithms to predict the behavior of tracked entities.

In this project, end-to-end deep learning models …

The Potential For Using Loyalty Rewards And Incentives Programs To Encourage Transit Ridership And Regional Transportation And Land Use Integration, Christopher E. Ferrell

Mineta Transportation Institute

Transit smart cards can be used as a tool for increasing transit ridership, increasing retail sales in transit-oriented developments (TODs) and eventually, increasing opportunities for retail development in TODs. Instead of providing separate loyalty rewards for each store, or chain of stores, such cards would provide loyalty rewards—in several possible forms, including free transit ride credits, cash rewards, retail purchase discounts, sweepstakes rewards—to all transit riders who patronize TOD retail businesses. Additional rewards could also be given to transit riders who live, work, and shop in TODs, and even to riders who take transit for specific shopping trips in TODs. …

Digitalization In Practice: The Fifth Discipline Advantage, Siu Loon Hoe

Research Collection School Of Computing and Information Systems

Purpose The purpose of this paper is to provide advice to organizations on how to become successful in the digital age. The paper revisits Peter Senge's (1990) notion of the learning organization and discusses the relevance of systems thinking and the other four disciplines, namely, personal mastery, mental models, shared vision and team learning in the context of the current digitalization megatrend. Design/methodology/approach This paper is based on content analysis of essays from international organizations, strategy experts and management scholars, and insights gained from the author's consulting experience. A comparative case study from the health and social sector is also …

Implementing Security-Enhanced Phr System In The Cloud Using Fame, Zuobin Ying, Wenjie Jiang, Ximeng Liu, Shengmin Xu

Research Collection School Of Computing and Information Systems

Personal Health Record (PHR) plays an important role in realizing the exchange and interaction of medical information as well as in managing chronic diseases. In the recent decade, plenty of researches have been carried out to resolve the secure sharing issue of PHR in the cloud via access control schemes. Attribute-based Encryption (ABE) is a promising technique, which implements access control by introducing the access policy. When ABE is used to construct access control scheme in the cloud, hiding and updating access policy have always been two research hotspots. However, all of the existing solutions only consider one of these …

A Mathematical Programming Model For The Green Mixed Fleet Vehicle Routing Problem With Realistic Energy Consumption And Partial Recharges, Vincent F. Yu, Panca Jodiwan, Aldy Gunawan, Audrey Tedja Widjaja

Research Collection School Of Computing and Information Systems

A green mixed fleet vehicle routing with realistic energy consumption and partial recharges problem (GMFVRP-REC-PR) is addressed in this paper. This problem involves a fixed number of electric vehicles and internal combustion vehicles to serve a set of customers. The realistic energy consumption which depends on several variables is utilized to calculate the electricity consumption of an electric vehicle and fuel consumption of an internal combustion vehicle. Partial recharging policy is included into the problem to represent the real life scenario. The objective of this problem is to minimize the total travelled distance and the total emission produced by internal …

Piezoceramic-Polymer And Piezoceramic-Cement Composites: A Brief Review, S Inthong, S Eitssayeam, J Tontrakoon, T Tunkasiri

Journal of Metals, Materials and Minerals

The physical properties of piezoceramic-polymers and lead-based or lead-free - Portland cement or geopolymer are described as part of this brief review. The connectivities such as 0-3, 1-3, 2-2 and 3-3 were employed to fabricate the composites. Their physical properties such as dielectric, coupling constant, acoustic impedance etc. were measured. The acoustic impedance obtained from the PZT-epoxy resin (0-3/1-3 connectivity) showed quite low. This can be further developed to match with water or human tissue for both hydrophone and medical applications. The properties of the composites containing leadbased or lead-free cement or geopolymer were also revealed. The results prove that …

Isothermal Aging Of Al-Ni-Sc Alloy Containing Al3ni Microfibers And Al3sc Nanoprecipitates, C Suwanpreecha, J P. Toinin, P Pandee, D C. Dunand, C Limmaneevichitr

Journal of Metals, Materials and Minerals

Binary Al-Sc alloys have excellent strength at room and elevated temperature up to 300°C due to coherent of Al3Sc nanoprecipitates. Binary Al-Ni alloys are an alternative alloy for high-temperature applications owing to high-thermal stability of Al3Ni microfibers. In this study, the hardness evolution at 300°C for up to 672 h for eutectic ternary Al-6Ni-0.4Sc (wt%) was studied and compared with binary Al-0.4Sc and Al-6Ni alloys. The Al-6Ni alloy maintains a constant hardness after aging at 300°C up to 672 h. Both Al-0.4Sc and Al-6Ni-0.4Sc alloys show strong precipitation strengthening response, with peak hardness reached after about 3 h aging, due …

Evaluating The Grinding Process Of Granites Using The Physico-Mechanical And Mineralogical Properties, S Kahraman, M Ucurum, E Yogurtcuoglu, M Fener

Journal of Metals, Materials and Minerals

Granitic rocks are sometimes ground for different purposes. Predicting the mean particle size (d50) is useful for planning and cost estimation of purposes. In order to investigate the possibility of predicting the d50 of ground rock from the physico-mechanical rock properties, six different granites were tested in the laboratory. First, the d50 values were correlated with the corresponding physico-mechanical properties. The simple regression analysis showed that there were no good correlations between the d50 and the physico-mechanical properties. Then, the multiple regression analysis was carried out and strong prediction equations were developed. It was also shown that the dominant parameter …

Optical And Luminescence Investigation Of Er3+ Doped In Na2o-Al2o3-P2o5 Glasses For Photonics Material Application, N Chanthima, N Kiwsakunkran, J Kaewkhao, N Sangwaranatee

Journal of Metals, Materials and Minerals

Optical and photoluminescence properties of Er3+ doped Na2O-Al2O3-P2O5 (NAPEr) glasses were prepared by conventional melt quenching technique at 1200°C. The absorption spectra have 11 peaks corresponded to 4I15/2 ground state to various excited energy levels. The absorption band at 1537 nm shows highest intensity in near-infrared (NIR) region. Also, it can be observed that the intensity of absorption bands increased on increase in concentrations of Er2O3. The Judd-Ofelt (JO) parameters (Ωλ, λ = 2, 4, and 6) are calculated using the absorption bands of the Er2O3 doped glass compositions. McCumber theory has been applied to determine the emission cross-sections (σe) …

Modelling And Fault Diagnosis Approach For Proton Exchange Membrane Fuel Cell Systems Incorporating Ambient Conditions, Saad Saleem Khan

Dissertations

Proton exchange membrane fuel cell (PEMFC), as a source of electrical power, provides numerous benefits such as zero carbon emission and high reliability as compared to wind and solar energy. PEMFC operates at very low temperature, high power density, and has very high durability as compared to other fuel cells. Being a non-linear power source with high sensitivity to ambient conditions variation, the prediction of PEMFC voltage and temperature is a complicated issue. The most common PEMFC models are classified as mechanistic models, semi-empirical models, and purely empirical methods. The mechanistic models are complex and require differential equations to predict …

E700xd Portable Doppler Radar Energy Systems Analysis, Brandon M. Bailey, Torrey J. Wagner, Jada Williams

Faculty Publications

Occurring in industrialized nations, inexpensive and abundantly available power is routinely taken for granted. However, energy resilience and to a lesser extent price are key concerns when considering potential solutions for disaster response, disaster relief, or military operations. The Department of Defense (DoD) currently uses a 5 kW generator to power the E700XD portable Doppler radar system when grid power is unavailable [1]. While the radar has an approximate power consumption of 2.5 kW, there is a potential for higher demand due to weather conditions [2]. This paper examines the cost of operating a currently installed generator, compared to the …

Seer: An Explainable Deep Learning Midi-Based Hybrid Song Recommender System, Khalil Damak, Olfa Nasraoui

Faculty and Staff Scholarship

State of the art music recommender systems mainly rely on either matrix factorization-based collaborative filtering approaches or deep learning architectures. Deep learning models usually use metadata for content-based filtering or predict the next user interaction by learning from temporal sequences of user actions. Despite advances in deep learning for song recommendation, none has taken advantage of the sequential nature of songs by learning sequence models that are based on content. Aside from the importance of prediction accuracy, other significant aspects are important, such as explainability and solving the cold start problem. In this work, we propose a hybrid deep learning …

Single-Cell Impedance Spectroscopy, David Paul Lange

Master's Theses

Impedance spectroscopy (IS) is an important tool for cell detection and characterization in medical and food safety applications. In this thesis, the Cal Poly Biofluidics Lab’s impedance spectroscopy system was re-evaluated and optimized for single-cell impedance spectroscopy. To evaluate the IS system, an impedance spectroscopy bioMEMS chip was fabricated in the Cal Poly Microfabcrication lab, software was developed to run IS experiments, and studies were run to validate the system. To explore IS optimization, Maxwell’s mixture theorem and the Schwartz-Christoffel transform were used to calculate an analytic impedance solution to the co-planar electrode system,a novel volume fraction to account for …