Structural Materials Commons^™

Engineering Properties And Microstructural Characteristics Of Cement And Geopolymer Based Mortars Using Nontraditional Supplementary Cementitious Materials, Mathialagan Sumesh

Student Works (2020-2029)

The concrete repair and rehabilitation industry grows rapidly due to deterioration, damage and defects in concrete structures. For various reasons, the concrete construction industry is not sustainable; because it consumes huge quantities of virgin materials, the usage of Portland cement as prime binder. The production of cement is a major contributor to greenhouse gas emissions. In addition, the high cost of commercial repair material. Therefore, it is necessary to develop cost-effective alternative repair materials for concrete repairs. There have been many standard repair materials available in the market, which are costly and not affordable to common people. However, research works …

Simultaneous Effects Of Rice Husk Silica And Silicon Carbide Whiskers On The Mechanical Properties And Morphology Of Sodium Geopolymer, Akm Rahman, Chirag Shah, Nihkil Gupta

Publications and Research

The current research is focused on developing a geopolymer binder using rice husk ash–derived silica nanoparticles. Four types of rice husks were collected directly from various rice fields of Bangladesh in order to evaluate the pozzolanic activity and compatibility of the derived rice husk ashes with precursors of sodium-based geopolymers. Silicon carbide whiskers were introduced into sodium-based geopolymers in order to evaluate the response of silicon carbide whiskers to the interfacial bonding and strength of sodium-based geopolymers along with rice husk ashes. Compression, flexural and short beam shear tests were performed to investigate the synergistic effect of rice husk ashes–derived …

Automatic Delamination Segmentation For Bridge Deck Based On Encoder-Decoder Deep Learning Through Uav-Based Thermography, Chongsheng Cheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Concrete deck delamination often demonstrates strong variations in size, shape, and temperature distribution under the influences of outdoor weather conditions. The strong variations create challenges for pure analytical solutions in infrared image segmentation of delaminated areas. The recently developed supervised deep learning approach demonstrated the potentials in achieving automatic segmentation of RGB images. However, its effectiveness in segmenting thermal images remains under-explored. The main challenge lies in the development of specific models and the generation of a large range of labeled infrared images for training. To address this challenge, a customized deep learning model based on encoder-decoder architecture is proposed …

Miniaturized Ultraviolet Imager Phase Iii, Bradley D. Albright, Nicolas A. Armenta, Colin W. Harrop

Mechanical Engineering

This document details the work to date, June 9, 2020, done by the Cal Poly Mechanical Engineering senior project team, Miniaturized Ultraviolet Imager: Phase III (MUVI III), sponsored by the University of California, Berkeley – Space Sciences Laboratory (UCB SSL). MUVI III is the third senior project team of an ongoing design, MUVI: the prototype of a 2U sized CubeSat intended to capture aurora images in the ionosphere. The first team, MUVI I, finished development of the UV imager. The second team, MUVI II, designed the mirror mounting and deployable door mechanisms. The goal of MUVI phase III is to …

Analysis Of Burning Wood In The Transient State And The Application To Structural Design, Roberta Veliz, Kimberly Guzman

Architectural Engineering

Determining the extent of the contribution of exposed timber on compartment fire dynamics in open floor plans is a complex process. Designers traditionally used compartmentalization design methods which create spaces where flashover is likely, given the fuel load and ventilation conditions. However, due to the large geometric dimensions and spread of fuel, fires in open floor plans are more likely to remain as localized or traveling fires. As such, an understanding of not only ignition potential but also flame spread is critical to characterizing the contribution of exposed timber. An integral step in characterizing the potential contribution is through an …

Prediction Of Flotation Efficiency Of Metal Sulfides Using An Original Hybrid Machine Learning Model, Rachel Cook, Keitumetse Cathrine Monyake, Muhammad Badar Hayat, Aditya Kumar, Lana Alagha

Materials Science and Engineering Faculty Research & Creative Works

Froth flotation process is extensively used for selective separation of base metal sulfides from uneconomic mineral resources. Reliable prediction of process outcomes (metal recovery and grade) is vital to ensure peak performance. This work employs an innovative hybrid machine learning (ML) model—constructed by combining the random forest model and the firefly algorithm—to predict froth flotation efficiency of galena and chalcopyrite in relation to various experimental process parameters. The hybrid model's prediction performance was rigorously evaluated and compared against four different standalone ML models. The outcomes of this study illustrate that the hybrid ML model has the prediction ability to process …

Effect Of Post-Consumer Content And Bioplastic Incorporation On Polymeric Resin In Consumer Applications, Shelby Bicknell

Electronic Theses & Dissertations

Controversy surrounds the use of plastic products, primarily due to their potentially negative impact on the environment at the end of their lifecycle. The most widely used plastics are manufactured from petrochemicals such as petroleum, coal or natural gas. Petrochemical plastics are not able to readily breakdown in the environment, which aggravates the existing pollution problems. Fortunately, there are eco-friendly alternatives to petrochemical-based plastics. Bioplastics may be derived from renewable sources, biodegradable, or both. Bio-based plastics are plastics that may be derived from renewable biomass sources including, but not limited to, vegetable oils, cornstarch, straw, woodchips, and food waste. They …

Applied-Force Oscillations In Avalanche Dynamics, Louis W. Mcfaul, Gregory Sparks, Jordan Sickle, Jonathan T. Uhl, Wendelin J. Wright, Robert Maass, Karin A. Dahmen

Faculty Journal Articles

Until now most studies of discrete plasticity have focused on systems that are assumed to be driven by a monotonically increasing force; in many real systems, however, the driving force includes damped oscillations or oscillations induced by the propagation of discrete events or “slip avalanches.” In both cases, these oscillations may obscure the true dynamics. Here we effectively consider both cases by investigating the effects of damped oscillations in the external driving force on avalanche dynamics. We compare model simulations of slip avalanches under mean-field dynamics with observations in slip-avalanche experiments on slowly compressed micrometer-sized Au specimens using open-loop force …

Comparative Analysis And Dynamic Response Of Garolites Under Temperature Spectrum Using Low Velocity Impact Test, Birendra Chaudhary

Honors Theses

The purpose of this study was to examine the dynamic response of three different grades of garolites under the temperature spectrum. High-Temperature G-11 Sheet (HTG), Impact Resistance Garolite E-glass (HIG), and Economical Garolite (EG) were tested using an Instron Dynatup 8250 impact tester. Three specimens were used for all three composites and were tested at 6 different temperatures, -10^oC, 25^oC, 50^oC, 100^oC, 150^oC and 200^oC using the Low-Velocity Impact Machine with 20 Kip punch shear load cell. The results showed that HIG had the highest resistance to punch …

Product Realization Capstone: Element Proof Safety Steps For Willie Price Lab School, Catherine Thomas, Allan Heuerman, Jared Mumme

Honors Theses

The purpose of this document is to describe the process we took to complete our capstone which paired the Center for Manufacturing Excellence with the Willie Price Lab School. The goal of the capstone was to remake step stools for the students of Willie Price, as the last stools failed to withstand weather damage. However, with the COVID-19 pandemic, plans were hindered, shifting the goal from actually producing the steps to creating instructions so that a younger Center for Manufacturing class could complete the production at a later date. Standardized Work Instructions, a detailed production plan, and engineering drawings were …

The Development Of All Solid-State Optical Cryo-Cooler, Junwei Meng

Optical Science and Engineering ETDs

This dissertation describes the development of an all solid-state optical cryo-cooler. Crystals of 10% wt. ytterbium-doped yttrium lithium fluoride (Yb³⁺:YLF) are used to cool an infrared HgCdTe sensor payload to an absolute temperature below 135 K, equivalent to delta T equal 138 K below ambient. This record level of cooling is accomplished with a single stage, in a completely vibration-free environment, with a corresponding cooling power of 190 mW. This milestone is made possible by the design and fabrication of an undoped YLF thermal link that efficiently shields the payload with a non-right angle kink from intense anti-Stokes …

Development Of Multi-Axial Fatigue Retrofits For Lock Gate Components, Logan Verkamp

Graduate Theses and Dissertations

Lock gates are essential infrastructure components to the United State (US) supply chain. They create large cost savings and environmental benefits when compared with traditional methods of transport (freight and rail). Because of the large quantity of goods and dependence on these shipping chains, the US economy can be drastically affected by an unexpected gate closure. Unfortunately, many lock gates within the US have reached or exceeded their designed life. Due to the intensity of cyclic loads and the environment, fatigue cracks have become a prominent issue. Developed cracks near the pintle region (a joint which the gate rotates and …

Diffusion Bonding Of Inconel 600 To Silicon Carbide For Next Generation High Temperature Applications, Yaiza Rodriguez Ortego

Boise State University Theses and Dissertations

Ceramic to metal interfaces are of interest for applications in extreme environments because they allow increased operational temperatures, resulting in greater thermodynamic efficiency in energy conversion processes. Ceramics offer high temperature corrosion resistance while metals offer robust and versatile solutions to assemblies. Understanding the solid-state reactions, the resulting interfacial microstructure, and the properties of the joints produced by diffusion bonding is essential for developing reliable ceramic to metal interfaces.

The combination of silicon carbide (SiC) and a nickel-based alloy (Inconel 600) offers improved strength and resistance to high temperature degradation. This work focuses on the understanding of the solid-state diffusion …

Effects Of Polytetrafluoroethylenemicro–Particles On Mechanical Andtribological Properties Of Glass Fiberreinforced Polyoxymethylene, Kunnan Singh Jasbir Singh

Student Works (2020-2029)

Reinforcing polyoxymethylene (POM) with glass fibers (GF) enhances its mechanical properties, but at the expense of tribological performance. Formation of a transfer film to facilitate tribo–contact is compromised due to the abrasiveness of GF. As a solid lubricant, for example, polytetrafluoroethylene (PTFE) significantly improves friction and wear resistance. The effects of chemically etched PTFE micro–particles on the fiber– matrix interface of POM/GF/PTFE composites have not been systematically characterized. This research investigated the effects of PTFE micro–particles on mechanical and tribological properties of POM/GF/PTFE composites. Since PTFE is immiscible with most polymers, the surface was etched using sodium naphthalene salt dissolved …

Spherical Cavity Expansion Approach For The Study Of Rigid-Penetrator’S Impact Problems, Mario Buchely, Alejandro Marañon

Materials Science and Engineering Faculty Research & Creative Works

In recent years, Spherical Cavity Expansion (SCE) theory has been extensively utilized to model dynamic deformation processes related to indentation and penetration problems in many fields. In this review, the SCE theory is introduced by explaining the different mathematical features of this theory, its solution, and a potential application to model the penetration of a rigid penetrator into a deformable target. First, a chronologically literature review of the most common models used to study this kind of penetration problems is introduced, focusing on the SCE theory. Then, the engineering model of penetration is presented using the SCE approach. The model …

Designing An Adjustable And Transportable Staircase, Allison Currey

Undergraduate Honors Thesis Projects

People climb stairs every day, whether it is at work, a store, or at home; however, there are populations such as people who are elderly, with pathologies, with Parkinson’s disease, or have suffered from a stroke that see climbing the stairs as a challenging task and it decreases their mobility and quality of life. Factors such as muscle weakness, strategy, and balance have been previously investigated in these populations during stair climbing. However, few studies have researched how stair climb ability, balance, and perception of difficulty are influenced by step height. The objective of this thesis is to design a …

Structural And Electronic Properties Of The Pure And Stable Elemental 3d Topological Dirac Semimetal Α-Sn, Maya N. Nair, Ivan Madarevic, Umamahesh Thupakula, Gertjan Lippertz, Niels Claessens, Pin-Cheng Lin, Harsh Bana, Sara Gonzalez, Giovanni Di Santo, Luca Petaccia, Lino M.C. Pereira, Chris Van Haesendonck, Margriet J. Van Bael

Advanced Science Research Center

In-plane compressively strained α-Sn films have been theoretically predicted and experimentally proven to possess non-trivial electronic states of a 3D topological Dirac semimetal. The robustness of these states typically strongly depends on purity, homogeneity, and stability of the grown material itself. By developing a reliable fabrication process, we were able to grow pure strained α-Sn films on InSb(100), without heating the substrate during growth nor using any dopants. The α-Sn films were grown by molecular beam epitaxy, followed by experimental verification of the achieved chemical purity and structural properties of the film’s surface. Local insight into the surface morphology was …

Dry And Wet Torrefaction Of Microalgal Biomass For Biochar Production As Bioenergy Sources, Yong Yang Gan

Student Works (2020-2029)

Increasing population in global and living standards have risen the consumption of global energy. Thermochemical conversion approaches hold great potential for the biomass conversion into energy applications. Among these approaches, torrefaction is a promising technique to enhance the biomass properties, making it more practical and suitable in biofuel applications. In this study, two different species of microalgae (third generation biofuel feedstock) including Chlorella vulgaris ESP-31 and FSP-E were used as feedstocks for dry and wet torrefaction. Dry torrefaction of microalgae was performed at temperatures of 200, 250 and 300 ºC, and holding times of 15, 30, 45 and 60 min, …

Performance Evaluation Of Lightweight Normal And Geopolymer Foamed Concrete Using Palm Oil Fuel Ash As Partial Replacement Of Binder, M .E. Alnahhal Ahmed

Student Works (2020-2029)

Carbon dioxide (CO2) emissions from Ordinary Portland Cement (OPC) have a detrimental effect on the environment and this had led many researchers to search for other alternatives in the form of sustainable cementitious materials. The depletion of natural resources and dumping the industrial by-products and waste materials are serious concern to our environment. This research focusses on the performance of using a palm oil industrial by-product, namely, palm oil fuel ash (POFA), as a partial replacement for OPC and fly ash (FA) in lightweight normal foamed concrete and lightweight geopolymer foamed concrete, respectively. Thus, using 10, 20, and 30% POFA …

Rc Mini Baja Car - Suspension And Chassis, Collin Mckenzie

All Undergraduate Projects

Two students have developed a unique design of the RC Baja Car to optimize functionality and performance. A Baja car is a remote controlled 1/10 scale car that is used for recreation or competition, usually meant for competing in the ASME Baja car competition versus various schools. The competition focuses on the best time achieved in different courses that utilize speed, turns, and jumps. The objective for the project was to create a unique suspension from previous individual’s projects by creating a four-link suspension in which allows more travel in the suspension of the car and maintains functionality with the …

Characterization Of Contact Resistance Properties Of Different Tlm Structure Designs, Nicole A. Karam Pannaci

Digital Repository: Showcase of Undergraduate Research Excellence

No abstract provided.

Carbon Oxidation At The Atomic Level: A Computational Study On Oxidative Graphene Etching And Pitting Of Graphitic Carbon Surfaces, Simon Schmitt

Theses and Dissertations--Mechanical and Aerospace Engineering

In order to understand the oxidation of solid carbon materials by oxygen-containing gases, carbon oxidation has to be studied on the atomic level where the surface reactions occur. Graphene and graphite are etched by oxygen to form characteristic pits that are scattered across the material surface, and pitting in turn leads to microstructural changes that determine the macroscopic oxidation behavior. While this is a well-documented phenomenon, it is heretofore poorly understood due to the notorious difficulty of experiments and a lack of comprehensive computational studies. The main objective of the present work is the development of a computational framework from …

Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis, Saurabh Shankar Shegokar

Dissertations, Master's Theses and Master's Reports

This study highlights the material behavior in riveting operation that includes buckling load analysis using ABAQUS. Finite Element Analysis is used to find the buckling load vs. Displacement results and validated with the results obtained in physical testing of rivet (POP Nut). A mesh sensitivity study is performed using ABAQUS to understand the optimum mesh size for this analysis. An axisymmetric model with contact properties is created and simulated to reduce the simulation time using ABAQUS. The results obtained through Finite Element Analysis show a good resemblance with the testing results. Design changes were suggested to achieve better results that …

Influence Of Rapid Solidification And Wrought Processing On Precipitation Strengthening And Deformation Mechanisms In Al-Sc-Zr Alloys, Yang Yang

Dissertations, Master's Theses and Master's Reports

Al-Sc-Zr alloys have drawn increasing attention in the last several decades due to their strengthening and coarsening resistance. In this study, solute concentrations of Sc and Zr were increased beyond their equilibrium solubilities without primary precipitate formation using melt-spinning. The melt-spun ribbon was metallurgically bonded into bulk shape using extrusion. With the proper aging treatment, the mechanical properties of the supersaturated melt-spun ribbon and extruded rod were found to be significantly higher than a baseline dilute alloy. Increased mechanical properties include microhardness, tensile strength at ambient-temperature, and compressive strength and threshold stress at and elevated-temperature. These increases were related to …

Multiscale Modeling Of Carbon Fibers/Graphene Nanoplatelets/Epoxy Hybrid Composites For Aerospace Applications, Hashim Al Mahmud

Dissertations, Master's Theses and Master's Reports

Significant research effort has been dedicated for decades to improve the mechanical properties of aerospace polymer-based composite materials. Lightweight epoxy-based composite materials have increasingly replaced the comparatively heavy and expensive metal alloys used in aeronautical and aerospace structural components. In particular, carbon fibers (CF)/graphene nanoplatelets (GNP)/epoxy hybrid composites can be used for this purpose owing to their high specific stiffness and strength. Therefore, this work has been completed to design, predict, and optimize the effective mechanical properties of CF/GNP/epoxy composite materials at different length scales using a multiscale modeling approach. The work-flow of modeling involves a first step of using …

Increasing Access To Pv Technology Through Sustainable Racking: A Review Of Existing Literature And Ground Mounted Fixed Tilt Designs, And What Can Be Done Next, Parijata Prabhakara

Dissertations, Master's Theses and Master's Reports

There is a lack of literature on the structural balance of systems (BOS), also called racking, for ground mount, fixed-tilt solar PV systems. Literature that exists discusses mostly rooftop racking and installations, additional wind loading, and weight considerations imposed on roofs, and little guidance is provided in building codes. The lack of peer-reviewed guidance on design requirements for domestic and large-scale application solar PV racking systems leaves most consumers relying on expensive, patented, off-the-shelf hardware. As PV cell technology and module costs have improved, we can start to focus on PV BOS improvements (particularly racking) and move towards sustainable designs …

Chloride Effect In Fly Ash Geopolymer Cement, Evan Dimmick

Williams Honors College, Honors Research Projects

The production of ordinary portland cement (OPC) poses a significant impact on the world's carbon dioxide emissions through the wide global use of concrete. Geopolymer cements (GPC) made from alkali activated fly ash can serve as a replacement to OPCs, reducing the carbon dioxide emissions by as much as 80%. GPCs exhibit adequate or superior mechanical performance to OPCs. The corrosion of carbon steel rebar in concrete occurs largely from chloride ion attack. The focus of this project will be to experimentally determine the coefficient of diffusion for chloride ions in GPCs and OPCs and compare to the corrosion performance …

Jominy Hardenability Tester With In-Situ Heating, Luke Allen

Williams Honors College, Honors Research Projects

This project centers on building a Jominy Hardenability tester with In-Situ heating for the manufacturing lab at the University of Akron. A new process and setup will be designed using engineering concepts in order to make the testing more efficient and safer for the teaching and testing of metal hardness. The current Jominy testing setup has efficiency issues within the transfer of specimen from induction heater to testing rig. Our design will simplify the design by creating a test rig that removes the traveling aspect of the specimen which will limit the amount of premature cooling done and will be …

The Corrosion Behavior Of Aisi 304l Stainless Steel In Simulated Concrete Pore Solution. And A New Marketing Plan For Stainless Steel Rebars., Kenny Aronson

Williams Honors College, Honors Research Projects

The purpose of this project is to study the corrosion behavior of AISI 304L stainless steel, and to present the results for a new marketing strategy for a steel rebar manufacturer. This experiment involved the usage of cyclic potentiodynamic polarization tests to investigate the effect of chlorides on the pitting corrosion behavior of AISI 304L stainless steel in a simulated concrete pore solution with 3.5 wt.% chlorides. The results of this experiment showed that the chlorides caused a large increase in the corrosion current density of AISI 304L stainless steel indicating increased susceptibility to general corrosion and pitting corrosion. The …

Table Top Dome Tester, Travis Bernard, Sarah Kassinger, Amanda O'Reilly, Scott Salerno

Williams Honors College, Honors Research Projects

The Erichsen Cupping Test was used as a basis to design a dome tester. The intention of a dome tester is to test sheet metal material properties in all directions. This was done by clamping a piece of sheet metal and using a piston and hydraulic press to punch through the material. The force used to punch the material and the height of the deforming material can be gathered and the sheet metal properties can then be calculated. At the end of the project the team was able to successfully design and manufacture a hydraulic dome tester. However, due to …