Materials Science and Engineering Commons^™

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Materials Science and Engineering Faculty Research & Creative Works

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Reinventing The Wheel, Esther K. Unti, Ahmed Z. Shorab, Patrick B. Kragen, Adam M. Menashe

Mechanical Engineering

Reinventing the Wheel selected tires and designed wheels for the 2018 Cal Poly, San Luis Obispo Formula SAE combustion vehicle. Available tire options were evaluated for steady-state and transient performance as well as vehicle integration. A single-piece composite wheel with hollow spokes was designed to meet stiffness, strength, and tolerance requirements. A detailed study of wheel loading and geometric structural efficiency was performed. Finite element analysis was used to iterate the geometry and laminate. A two-piece male mold was designed and machined to manufacture the wheel. Removable silicone inserts were used to create the hollow spokes.

Process-Property-Microstructure Relationships In Laser-Powder Bed Fusion Of 420 Stainless Steel., Subrata Deb Nath

Electronic Theses and Dissertations

Laser-powder bed fusion (L-PBF) is an additive manufacturing technique for fabricating metal components with complex design and customized features. However, only a limited number of materials have been widely studied using L-PBF. AISI 420 stainless steel, an alloy with a useful combination of high strength, hardness, and corrosion resistance, is an example of one such material where few L-PBF investigations have emerged to date. In this dissertation, L-PBF experiments were conducted using 420 stainless steel powders to understand the effects of chemical composition, particle size distribution and processing parameters on ensuing physical, mechanical and corrosion properties and microstructure in comparison …

Low Temperature Desiccants In Atmospheric Water Generation., Sunil Gupta

Electronic Theses and Dissertations

Surging global water demand as well as changes to weather patterns and over exploitation of natural water sources, such as ground water, has made potable water a critical resource in many parts of the World already – one rapidly heading towards a crisis situation. Desalination has been adopted as a solution – this is however energy intensive and impractical for most of the developing countries - those most in need of water. A renewable source of energy is solar thermal and solar photovoltaic. A plentiful source of water is the humidity in the atmosphere. This research is to push the …

Growth And Characterization Of Silicon-Germanium-Tin Semiconductors For Future Nanophotonics Devices, Bader Saad Alharthi

Graduate Theses and Dissertations

The bright future of silicon (Si) photonics has attracted research interest worldwide. The ultimate goal of this growing field is to develop a group IV based Si foundries that integrate Si-photonics with the current complementary metal–oxide–semiconductor (CMOS) on a single chip for mid-infrared optoelectronics and high speed devices. Even though group IV was used in light detection, such as photoconductors, it is still cannot compete with III-V semiconductors for light generation. This is because most of the group IV elements, such as Si and germanium (Ge), are indirect bandgap materials. Nevertheless, Ge and Si attracted industry attention because they are …

Fabrication And Characterization Of Electrochemical Glucose Sensors, Mohammed Marie

Graduate Theses and Dissertations

Electrochemical sensors based on the nanostructure of the semiconductor materials are of tremendous interest to be utilized for glucose monitoring. The sensors, based on the nanostructure of the semiconductor materials, are the third generations of the glucose sensors that are fast, sensitive, and cost-effect for glucose monitoring.

Glucose sensors based on pure zinc oxide nanorods (NRs) grown on different substrates, such ITO, FTO, and Si/SiO2/Au, were investigated in this research. Silicon nanowire (NW)- based glucose sensors were also studied. First, an enzyme-based glucose sensor was fabricated out of glass/ITO/ZnO NRs/BSA/GOx/nafion membrane. The sensor was tested amperometrically at different glucose concentrations. …

Comparative Study Of Power Semiconductor Devices In A Multilevel Cascaded H-Bridge Inverter, Kenneth Mordi

Graduate Theses and Dissertations

This thesis compares the performance of a nine-level transformerless cascaded H-bridge (CHB) inverter with integrated battery energy storage system (BESS) using SiC power MOSFETs and Si IGBTs. Two crucial performance drivers for inverter applications are power loss and efficiency. Both of these are investigated in this thesis. Power devices with similar voltage and current ratings are used in the same inverter topology, and the performance of each device is analyzed with respect to switching frequency and operating temperature. The loss measurements and characteristics within the inverter are discussed. The Saber® simulation software was used for the comparisons. The power MOSFET …

Compensation Of Vertical Position Error Using A Force–Deflection Model In Friction Stir Spot Welding, Jinyoung Yoon, Cheolhee Kim, Sehoon Rhee

Mechanical and Materials Engineering Faculty Publications and Presentations

Despite increasing need for friction stir spot welding (FSSW) for high-temperature softening materials, system deflection due to relatively high plunging force remains an obstacle. System deflection results in the vertical position error of a welding tool and insufficient plunge depth. In this study, we used adaptive control to maintain plunge depth, the plunging force was coaxially measured, and the position error was estimated using a force–deflection model. A linear relationship was confirmed between the force and deflection; this relationship is dependent on the stiffness of the welding system while independent of process parameters and base materials. The proposed model was …

Analysis Of Mechanical Properties And Permeability Of Sand Moulding By Using Eggshell In Sand Casting, Wahyu Kurnianto, Poppy Puspitasari, Wahono Wahono

Journal of Mechanical Engineering Science and Technology (JMEST)

This study aimed to analyse the usage of Eggshell as mixture material of bentonite in metal casting process which used dried sand moulding. Eggshell variations in this study were 4%, 7%, 10% eggshell, and additional 3% of bentonite on each sample. This study used pre-experimental method and included to OneShot Case Study model. The highest strength was found on the sample 3 ES 10%. Tensile strength of dried sand moulding reach up to 0.09 kg/cm2, the compressive strength of dried sand moulding reached up to 3.11 kg/cm2, and the shear strength of dried sand moulding reached up to 1.13 kg/cm2. …

Drop Generation Using Cross-Flow In Rigid Body Rotation, Haipeng Zhang

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

Inspired by crossflow membrane droplet generation and microfluidic droplet generation, I propose an easy method to generate monodisperse drops using cross-flow caused by rigid body rotation. In this approach, a dispersed phase (DP) liquid was injected through a stationary vertical needle into an immiscible continuous phase (CP) liquid which was in rigid body rotation. A DP drop growing at the end of the needle experienced fluid dynamic forces from the horizontal CP flow, and it was detached from the needle when it had grown to a certain size. This study investigated the relationship between the resultant size of drops and …

Determining The Degree Of [001] Preferred Growth Of Ni(Oh)2 Nanoplates, Taotao Li, Ning Dang, Wanggang Zhang, Wei Liang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Determining the degree of preferred growth of low-dimensional materials is of practical importance for the improvement of the synthesis methods and applications of low-dimensional materials. In this work, three different methods are used to analyze the degree of preferred growth of the Ni(OH)₂ nanoplates synthesized without the use of a complex anion. The results suggest that the preferred growth degree of the Ni(OH)₂ nanoplates calculated by the March parameter and the expression given by Zolotoyabko, which are based on the analysis and texture refinement of the X-ray diffraction pattern, are in good accordance with the results measured by …

Cellulose-Specific Type B Carbohydrate Binding Modules: Understanding Oligomeric And Non-Crystalline Substrate Recognition Mechanisms, Abhishek A. Kognole, Christina M. Payne

Chemical and Materials Engineering Faculty Publications

Background: Effective enzymatic degradation of crystalline polysaccharides requires a synergistic cocktail of hydrolytic enzymes tailored to the wide-ranging degree of substrate crystallinity. To accomplish this type of targeted carbohydrate recognition, nature produces multi-modular enzymes, having at least one catalytic domain appended to one or more carbohydrate binding modules (CBMs). The Type B CBM categorization encompasses several families (i.e., protein folds) of CBMs that are generally thought to selectively bind oligomeric polysaccharides; however, a subset of cellulose-specific CBM families (17 and 28) appear to bind non-crystalline cellulose more tightly than oligomers and in a manner that discriminates between surface topology.

Results: …

Analysis Of Casting Defect, Tensile Strength, And Hardness Of Al-Si Casting Alloy With Percentage Variation Of Clay Binder Bangkalan, Imam Muhtarom, Sunomo Sunomo

Journal of Mechanical Engineering Science and Technology (JMEST)

Casting is one of method that used in forming the work piece by melting specific metal and pouring into moulding that has been prepared. This study aimed to determine the effect of the use of Bangkalan clay as binder in sand moulding against tensile strength, hardness, and defects in Al-Si casting alloy by using gravity casting method. The method used in this study was experimental method then using descriptive analysis. Descriptive analysis included explanation of the test result of tensile strength, hardness, and the type of surface defect of Al-Si casting. Based on the research result obtained the highest shear …

Analysis Of Hardness, Quality And Fluidity Al-Si Casting Result By Using Clamshell (Placuna Placenta) As The Mixture Of Sand Moulding, Shikh Mohd Shahrul Nizan Shikh Zahari, Saif Aziz Saputra, Putut Murdanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Metal is an element that cannot be separated from human life. Almost all of human activities includes metal element in it. Metals can be formed through several ways, one of which is metal casting. Metal casting is one of technique in producing products where the metal was melted in crucible and then poured in a moulding which is similar to the original shape of the product. Moulding that are commonly used are sand moulding. Commonly, binder which used in sand casting process is bentonite. Bentonite, was kind of mineral which can be run out during its usage. This study aimed …

The Analysis Of Permeability And Mechanical Properties Of Sand Moulding Using Mixed Material Clamshell (Placuna Placenta) On Sand Casting, Kritchakhris Nawettanaprasert, Zakaria Bagus Aminanta, Putut Murdanto

Journal of Mechanical Engineering Science and Technology (JMEST)

This study objected to determine mechanical properties of sand moulding by conducting tensile test, compressive and shear test, and also permeability test. This study also had the other objective that was analyse clamshell (Placuna placenta) as mixture material for bentonite as binder in manufacturing sand moulding in order to reduce the usage of bentonite. The method that used in this study was pre-experimental method with One-Shot Case Study model. The best mechanical properties obtained on sample 3 clamshell 11%, permeability results obtained was 190 ml/min, tensile strength results obtained for the dry sand was 0.015 kg/cm2, compressive strength obtained for …

Water Processable N-Type Organic Semiconductor, Ruben S. Riquelme, Matthew Collins Weisenberger, Camila F. Gomez

Center for Applied Energy Research Faculty Patents

The present invention concerns a water-processable n-type semiconductor comprised of polyvinylpyrrolidone (PVP), carbon nanotubes (CNTs) and poly(ethyleneimine) (PEI). The semiconductors are prepared by providing PVP and CNTs in a hydrophilic slurry and dispersing therein small amounts of PEI.

The Feasibility Of High Strength Stainless Steel In Prestressing Applications For Pile Design, Cara Morton

USF Tampa Graduate Theses and Dissertations

Approximately 50% of the Nation’s infrastructure was built over 40 years ago for a 50 year service life according to the National Association of Corrosion Engineers [72]. To mitigate the cost of major repair or replacement at 50 years, AASHTO now requires all new bridge construction to have a 100 year service life. One of the main challenges in achieving this goal is avoiding corrosion, especially in warm, saltwater environments like those found in the Southeastern United States. Elements that cross the waterline (piles) are a weak link the infrastructure. Good quality concrete easily maintains a service life of 75+ …

Linking Lignin Source With Structural And Electrochemical Properties Of Lignin-Derived Carbon Materials, Wenqi Li, Yan Zhang, Lalitendu Das, Yikai Wang, Mi Li, Namal Wanninayake, Yunqiao Pu, Doo Young Kim, Yang-Tse Cheng, Arthur J. Ragauskas, Jian Shi

Biosystems and Agricultural Engineering Faculty Publications

Valorization of lignin to high-value chemicals and products along with biofuel production is generally acknowledged as a technology platform that could significantly improve the economic viability of biorefinery operations. With a growing demand for electrical energy storage materials, lignin-derived activated carbon (AC) materials have received increasing attention in recent years. However, there is an apparent gap in our understanding of the impact of the lignin precursors (i.e., lignin structure, composition and inter-unit linkages) on the structural and electrochemical properties of the derived ACs. In the present study, lignin-derived ACs were prepared under identical conditions from two different lignin …

Characterization Of Nanomaterials For Thermal Management Of Electronics, Amit Rai

Doctoral Dissertations

Recently, there has been a growing interest in flexible electronic devices as they are light, highly flexible, robust, and use less expensive substrate materials. Such devices are affected by thermal management issues that can reduce the device’s performance and reliability. Therefore, this work is focused on the study of the thermal properties of nanomaterials and the methods to address such issues. The goal is to enhance the effective thermal conductivity by adding nanomaterials to the polymer matrix or by structural modification of nanomaterials. The thermal conductivity of copper nanowire/polydimethylsiloxane and copper nanowire/polyurethane composites were measured and showed more than threefold …

Nanoparticle Catalytic Enhancement Of Carbon Dioxide Reforming Of Methane For Hydrogen Production, Nicholas Groden

Doctoral Dissertations

The U.S. produces 5559.6 million metric tons of carbon dioxide annually, of which 21% is produced by industrial processes. Steam reforming, an industrial process that accounts for 95% of all hydrogen production in industry, produces 134.5 million metric tons of carbon dioxide or around 11% of the total carbon dioxide produced by industry. This carbon dioxide is then either emitted or goes through a sequestration process that accounts for 75% of the plant's operational costs. An alternative reaction to steam reforming is dry reforming, which utilizes carbon dioxide rather than emitting it and can be used in conjunction with current …

Electrical Characterization Of Graphene And Nanodiamond Nanostructures, A Z M Nowzesh Hasan

Doctoral Dissertations

The electrical characterization on two-dimensional carbon-based graphene and nanodiamond materials was performed to improve charge transport properties for the label-free electrical biosensors. The charge transport in solution-gated graphene devices is affected by the impurities and disorders of the underlying dielectric interface and its interaction with the electrolytes. Advancement in field-effect ion sensing by introducing a dielectric isomorph, hexagonal boron nitride between graphene and silicon dioxide of a solution-gated graphene field-effect transistor was investigated. Increased transconductance due to increased charge carrier mobility is accompanied with larger ionic sensitivity. These findings define a standard to construct future graphene devices for biosensing and …

Effective Magnetic And Electric Response Of Composite Materials, Mona Hassan Alsaleh

Doctoral Dissertations

Metamaterials (MMs) are nanocomposite materials consisting of metal-dielectric resonators much smaller in size than the wavelength of the incident light. Common examples of metamaterials are based on split ring resonators (SRRs), parallel wires or strips and fishnet structures. These types of materials are designed and fabricated in order to provide unique optical responses to the incident electromagnetic radiation that are not available in naturally existing materials. The MMs can exhibit unusual properties such as strong magnetism at terahertz (THz) and optical frequencies. Additionally, negative index materials (NIMs) can provide negative index of refraction which can be used in many applications …

Metal Segregation During The Solidification Of Titanium-Aluminum Alloys For 3d Printing Applications, Jwala Parajuli

Master's Theses

Titanium-Aluminum alloys are one of the widely used alloys in multiple engineering applications. They are highly preferred in Selective Laser Melting (SLM) processes due to their low density, high melting temperature, and good strength. Segregation occurs during the solidification of most alloys and produces a non-uniform distribution of atoms. In SLM, segregation may depict the type of adhesion between the two deposited interfacial layers and the strength between the interphase between an already solidified layer and a new one, and overall, the quality of the printed part. In order to avoid segregation, the understanding of the segregation behavior at atomistic …

Mechanical Characterization Of Expanded Polystyrene Spheres Embed Sandwich Composites For Packaging Applications, Maheswaran R, Arockia Reemas S

Journal of Applied Packaging Research

This paper addresses on study of development of new packaging material comprising Expanded Polystyrene Spheres (EPS) embedded epoxy polymer based sandwich composites with aluminium skin. The density of the packing material is controlled by varying the volume of embedded spheres. In this study, the Flexural and Compression performance of Expanded Polystyrene Spheres (EPS) embedded polymer based sandwich composites with aluminium skin are investigated. The EPS volume percent in the core is 25% with epoxy matrix which makes the the density less than 1 g/cm3 for the composite. The fabricated Sandwich Composite are very light weight, the density is less than …

Early Detection Of Corrosion Via Hydrogel-Based Spectroelectrochemical Sensors, Capri Ann Price

Dissertations and Theses

The backbone of the industrialized world is comprised of refined, zerovalent metal, a material which thermodynamically favors an oxidative return to more chemically stable states. There are many methods used to slow or delay this process, such as protective coatings, sacrificial anodes, and alloys, but no method can entirely prevent corrosion. This body of work instead proposes detecting the earliest chemical markers of corrosion: that is, metal ions as they solubilize from a metal surface. Such information would allow maintenance personnel to make informed decisions about the necessity or lack thereof of preventive maintenance, and intervene before advanced damage has …

Advances In Automotive Conversion Coatings During Pretreatment Of The Body Structure: A Review, Mark Doerre, Larry Hibbitts, Gabriela Patrick, Nelson K. Akafuah

Institute of Research for Technology Development Faculty Publications

Automotive conversion coatings consist of layers of materials that are chemically applied to the body structures of vehicles before painting to improve corrosion protection and paint adhesion. These coatings are a consequence of surface-based chemical reactions and are sandwiched between paint layers and the base metal; the chemical reactions involved distinctly classify conversion coatings from other coating technologies. Although the tri-cationic conversion coating bath chemistry that was developed around the end of the 20th century remains persistent, environmental, health, and cost issues favor a new generation of greener methods and materials such as zirconium. Environmental forces driving lightweight material selection …

Effect Of Cross-Section-Change Induced Advective Flow On The Primary Dendrite Array Morphology Of Hypoeutectic Pb-Sb Alloys During Directional Solidification, K. Pandit, S. R. Upadhyay, Surendra N. Tewari

Chemical & Biomedical Engineering Faculty Publications

The morphology and distribution of primary dendrites have been examined in Pb-2.2, 5.8 and 10.8 wt. pct. Sb alloy samples directionally solidified (DSed) in ampoules shaped like an hour-glass to examine the influence of cross-section change induced advective flow on the cellular/dendritic interface. This sample design increases the advective flow of the melt towards the array tips, as the liquid-solid interface enters the neck of the ampoule, and then decreases it as the interface exits the neck. The warm solute-rich melt flowing towards the growth front suppresses the extent of side-branching, decreases the primary dendrite spacing, and increases the primary …

Structural Transformations In Porous Glasses Under Mechanical Loading. Ii. Compression, Nikolai V. Priezjev, Maxim A. Makeev

Mechanical and Materials Engineering Faculty Publications

The role of porous structure and glass density in response to compressive deformation of amorphous materials is investigated via molecular dynamics simulations. The disordered, porous structures were prepared by quenching a high-temperature binary mixture below the glass transition into the phase coexistence region. With decreasing average glass density, the pore morphology in quiescent samples varies from a random distribution of compact voids to a porous network embedded in a continuous glass phase. We find that during compressive loading at constant volume, the porous structure is linearly transformed in the elastic regime and the elastic modulus follows a power-law increase as …

Vertical Transport Study Of Iii-V Type-Ii Superlattices, Zahra Taghipour

Optical Science and Engineering ETDs

Type-II strained layer superlattice (T2SL) semiconductors hold great promise for mid- and long-wavelength infrared photodetectors. While T2SL-based materials have advanced significantly in the last three decades, an outstanding challenge to improve the T2SLs is to understand the carrier transport and its limitations, in particular along the superlattice growth layers.

In this dissertation, an overview of the current state-of-the-art InAs/GaSb T2SLs is presented. Fundamental semiconductor device equations and transport properties, including miniband conduction and the drift-diffusion parameters, are reviewed, and the fundamental limiting factors in carrier's transport are discussed. Furthermore, the standard method of electron-beam-induced current technique to measuring these parameters …

Prediction Of Metal Sample Failure From Scanning Electron Microscope Images Using Deep Learning Neural Network, Lawrence Madriaga, Ivan Novikov, Morteza Nurcheshmeh

Posters-at-the-Capitol

We present the preliminary results on using a deep learning neural network to predict a metal sample failure based on a set of images obtained with a Scanning Electron Microscope.

Various metal alloy samples were prepared according to ASTM E8/E8M-11 standards for a tensile test. Each sample was prepared for circle grid analysis and then stressed on a tensile machine. Stress and strain values were obtained for each position along the sample by measuring dimensions of each elongated circle. Increasing stress and strain values were found closer to the breakage of the sample with low values found at the holding …