Engineering Commons^™

Utilization Of Fly Ash From Power Plant For Adsorption Of Hydrocarbon Contamination In Water, J Sasithorn, D Wiwattanadate, S Sangsuk

Journal of Metals, Materials and Minerals

Adsorption efficiency of polycyclic aromatic hydrocarbons (PAHs) contamination in water with rice husk fly ash from a power plant was investigated in comparison with coal fly ash and silica from rice husk fly ash, with and without surface treatment. Naphthalene was used as a representative for PAHs, and Cethyltrimethylammoniumbromide (CTAB) was used as surface treating agent for the present study. Various factors, such as shaking rate, shaking time, pH of naphthalene aqueous solution, and adsorbentnaphthalene weight ratio, were investigated to identify the optimum condition for each adsorbent. Upon using 0.3 g adsorbent in 100 ml of 10 mg/l naphthalene solution, …

An Investigation Of Microstructural Change Of Low Alloy Steel Aisi 4150 By Seebeck Coefficient, T Samran, P Termsuksawad

Journal of Metals, Materials and Minerals

Low alloyed steels, whose hardness can be modified by heat treatment, have been widely used in various applications. After heat treatment, they are normally destructively characterized and tested by many approaches via optical microscope and hardness testing. It is useful to develop a non-destructive method relating to its properties and microstructures. The proposed non-destructive approach in this study is the Seebeck coefficient measurement. The materials in this study were carbon steels AISI 4150 rod with a diameter of 1.3 cm and length of 3 cm. The specimens were heat-treated at 900ºC for 1 hour and were then cooled to room …

Boron Carbide Based Solid State Neutron Detectors: The Effects Of Bias And Time Constant On Detection Efficiency, Nina Hong, John Mullins, Keith Foreman, Shireen Adenwalla

Shireen Adenwalla Papers

Neutron detection in thick boron carbide(BC)/n-type Si heterojunction diodes shows a threefold increase in efficiency with applied bias and longer time constants. The improved efficiencies resulting from long time constants have been conclusively linked to the much longer charge collection times in the BC layer. Neutron detection signals from both the p-type BC layer and the n-type Si side of the heterojunction diode are observed, with comparable efficiencies. Collectively, these provide strong evidence that the semiconducting BC layer plays an active role in neutron detection, both in neutron capture and in charge generation and collection.

Feasibility Of Manipulating Correlated Color Temperatures With A Phosphor Converted High-Powered Light Emitting Diode White Light Source, Matthew Michael Little

Master's Theses

In this thesis we examine the feasibility of developing a white light source capable of producing colors between 2500 and 7500 Kelvin on the black-body radiator spectrum by simply adjusting amperage to a blue and ultraviolet (UV) light emitting diode (LED). The purpose of a lighting source of this nature is to better replicate daylight inside a building at a given time of day. This study analyzes the proposed light source using a 385 nm UV LED, a 457 nm blue LED, a 479 nm blue LED, a 562 nm peak cerium doped yttrium aluminum garnet (YAG:Ce) phosphor, and a …

The Effects Of Carbon, Boron And Vanadium On The Microstructural Evolution And Hardness Of Steel-Based Hardfacing Alloys, Kyle Rafa

Materials Engineering

Current hardfacing alloys provide insufficient wear resistance due to either cracking or significant material wear. To increase wear resistance of steel-based hardfacing alloys, the effects of composition on microstructure and hardness were investigated in a progression of alloys. Initially, seven new alloys were prepared varying the carbon-boron ratio with the total constant at 3 wt%. Small arc-melt cast circular ingots were produced roughly 1 x 0.5 inches. Metallography provided insufficient phase magnification, thus a SEM equipped with EDS was used, allowing for microstructure and phase composition analysis. Four distinct carbide phases were found and image analysis software allowed for carbide …

The Characterization And Analysis Of In-Vitro And Elevated Temperature Repassivation Of Ti-6al-4v Via Afm Techniques, Aaron J. Guerrero

Master's Theses

ABSTRACT

The Characterization and Analysis of In-vitro and Elevated Temperature Repassivation of

Ti-6Al-4V via AFM Techniques

Aaron J Guerrero

Research in the corrosion of orthopaedic implants is a growing research field where implants have been known to show adverse effects in patients who have encountered the unfortunate dissolution of their implants due to corrosion. Once corrosion begins within the body, many adverse biological reactions can occur such as late on-set infections resulting in severe health complications. The focus of this research is specifically related to the problem of late on-set infections caused by localized corrosion of orthopaedic implants. In medical …

Design, Fabrication, Structural Testing, And Numerical Analysis Of A Small Scale Composite Wing, Jacob David Gaunt, Juan Carlos Flores, Vincent Andrew Perry

Aerospace Engineering

A small scale composite wing based on a design found on an experimental aircraft was designed, constructed, and tested dynamically and statically. The wing was constructed similarly to an experimental aircraft wing. The performed static test was intended to produce pure bending. Strain gages were used to measure strains on the wing structure. The strains were converted to stresses to aid in analysis. The static test results suggested that the wing was actually under torsion. Four structural modes were found from the static test. A finite element analysis model was made to compare experimental results to numerical analytical results. The …

Irrigation Leak Detection: Using Flow Rate Sensors To Detect Breaks In An Irrigation System, Adam Openshaw, Kalvin Vu

Computer Engineering

This report details the exploration and invention of a mechanism that can detect breaks in an irrigation system. With the ultimate goal of conserving water, we have designed an inexpensive, self sustaining flow rate monitor that can be used to identify anomalies in an irrigation system and wirelessly communicate the status of the system to a base station. Our implementation can also determine the direction of the anomaly based on the nature of the anomaly itself. This means that multiple monitors can be used to pinpoint the location of a break within the system in addition to merely detecting its …

Characterization Of Aluminum-Boron Carbide Particulate Metal Matrix Composites, Eric Blank

Materials Engineering

The analysis of die-cast 380 aluminum-boron carbide particulate metal matrix composites (MMC) was performed in order to see if the samples had the required tensile strength of 300 MPa. 10wt% B4C die-cast samples were produced and tested. Half were heat treated to the T6 condition and the others were left as cast. Using ASTM standard B 557M it was found that the average tensile strength for the as-cast samples was 130 MPa and the heat treated samples had a tensile strength of 93 MPa. These values were both lower than expected. The heat treated samples were not expected to have …

Effects Of A Solution Anneal Quench Delay On The Heat Treatment Response Of Aluminum 2219-T6, Daniel James Filomeo

Materials Engineering

The ageing response for aluminum 2219-T6 was investigated to determine the effects a quench delay (QD) could have on tensile properties. Before testing commenced, furnace surveys were conducted to ensure they could meet the required temperature stability of + 10˚F (+6˚C). MIL-H-6088 specified a maximum quench delay of 15 seconds for parts thicker than 2.29 mm (0.090 in). An investigation was conducted on how different quench delay times changed the ageing response of T6 heat treated for Al 2219. Heat treatments were performed according to the ASM Handbook. Preliminary tests were performed on 1-1.5 in. cube blocks of Al 2219 …

Validation Of A Secondary Fabric Supplier And Characterization Of Alternate Cores For Use In The Aptera 2e Sandwich Core Composite, Bryan Rogers

Materials Engineering

Polymer matrix composites’ high strength to weight ratio has made them an ideal material choice for use in lightweight transportation vehicles. Aptera Motors, a company based out of Oceanside, CA, is currently developing a next-generation high efficiency passenger vehicle called the Aptera 2e. The 2e’s body is composed of a sandwich core composite containing laminates of E-glass fibers embedded within an epoxy matrix sandwiched between a polyester hexagonal core. This project looked to validate a secondary fabric supplier for use in Aptera’s composite and characterize the core shear properties of two alternate core materials for future iterations of Aptera’s vehicle. …

Enhanced Light Extraction Efficiency From Gan Light Emitting Diodes Using Photonic Crystal Grating Structures, Simeon S. Trieu

Master's Theses

Gallium nitride (GaN) light emitting diodes (LED) embody a large field of research that aims to replace inefficient, conventional light sources with LEDs that have lower power, higher luminosity, and longer lifetime. This thesis presents an international collaboration effort between the State Key Laboratory for Mesoscopic Physics in Peking University (PKU) of Beijing, China and the Electrical Engineering Department of California Polytechnic State University, San Luis Obispo. Over the course of 2 years, Cal Poly’s side has simulated GaN LEDs within the pure blue wavelength spectrum (460nm), focusing specifically on the effects of reflection gratings, transmission gratings, top and bottom …

Optimization Of P3ht-Pcbm Polymer Solar Cells Through Device Simulation And Manufacturing, James Boom

Computer Engineering

Given a good model and implementation of that model, computer simulation can be used to reduce the time and material costs of research. To this end I worked with other students to manufacture, test and simulate the single layer P3HT-PCBM solar cell. Using the data collected from this project, future work can then be done with the project's simulator to further optimize these types of solar cell devices.

Polyenvi, Stephen Beard, Josh Engel, Paul Fake, Diego Flores, Alvaro Nunez, Miguel Wong

Electrical Engineering

Poor indoor air quality is a problem that is recognized by the Environmental Protection Agency (EPA) to cause health issues. In order to raise awareness of this problem, this document outlines the construction of a device that economically measures air quality through five metrics: dust, smoke, ozone, humidity, and temperature. The device integrates with a router to provide users access to information about their indoor air quality anywhere over the internet as well as local access to the data via an LCD mounted on the router. By increasing indoor air quality awareness, this device will aid users in making adjustments …

Limitations Of Poole–Frenkel Conduction In Bilayer Hfo2/Sio2 Mos Devices, Richard G. Southwick Iii, Justin Reed, Christopher Buu, Ross Butler, Gennadi Bersuker, William B. Knowlton

Materials Science and Engineering Faculty Publications and Presentations

The gate leakage current of metal–oxide– semiconductors (MOSs) composed of hafnium oxide (HfO₂) exhibits temperature dependence, which is usually attributed to the standard Poole–Frenkel (P–F) transport model. However, the reported magnitudes of the trap barrier height vary significantly. This paper explores the fundamental challenges associated with applying the P–F model to describe transport in HfO₂/SiO₂ bilayers in n/p MOS field-effect transistors composed of 3- and 5-nm HfO₂ on 1.1-nm SiO₂ dielectric stacks. The extracted P–F trap barrier height is shown to be dependent on several variables including the following: the temperature range, method …

Determining The Optimal Material For Coffee Packaging: Oxygen Transmission Rates And Ink Abrasion Resistance, Laura Kiyoi

Graphic Communication

No abstract provided.

Novel Micron- And Nano-Scale Energetic Materials For Advanced Gun Propulsion, Their Material Properties, And Their Effects On Ballistic Performance, Thelma Gatuz Manning

Dissertations

This dissertation focused on the investigation of novel materials that are both energetic and inert in their micron- and nano-scale crystalline form. The characterization of the materials properties and its effects on the ballistic performance when incorporated into a composite material were evaluated as a gun propellant for application in a future weapon system for the US Army. Some of these materials may find dual use in civilian applications. Applications in small and medium arms, artillery, tank, aircraft, and shipboard gun systems will all benefit from these advancements. Not only will gun system performance be improved for greater stand-off range …

Formation Of Screen-Printed Contacts On Multicrystalline Silicon (Mc-Si) Solar Cells, Vishal R. Mehta

Dissertations

Commercial multicrystalline silicon (me-Si) solar cells use screen-printing process for depositing both the Ag paste based gridded front and Al based back (whole area) metal contacts.. This thesis relates to experimental and theoretical studies of contact formation mechanisms in silicon solar cells. Temperature distribution studies during optical processing by. attached thermocouples to cells indicates that the maximum temperature reached under the front silver metal is less. than 800°C; this is lower than the eutectic point of Ag-Si (≈835°C). An analysis of the interaction of Ag particles and Si via the constituents of glass is given. This mechanism leaches metallic ions …

Multi-Component Boron Coatings On Low Carbon Steel Aisi 1018, Naruemon Suwattananont

Dissertations

Boronizing and metalizing are thermo-chemical surface hardening treatments in which boron and metal atoms diffuse into the metal substrate forming metallic boride layers, providing complex properties of B-Me-Fe system.

To study multi-component boron coatings on low carbon steel AISI 1018, the simultaneous powder pack method of boronizing and metalizing was selected to perform the coatings. One B-Fe system and eight boron-metal (B-Me-Fe) systems from transition metals group IVB (Ti, Zr, Hf), group VB (Nb, Ta), and group VIB (Cr, Mo, W) were studied. The system specimens were thermo-chemically treated at 950°C for 4 hours in a crucible containing powder mixture …

Interfacially Polymerized Thin Film Composite Membranes On Microporous Polypropylene Supports For Reverse Osmosis Desalination, Chao Li

Theses

The important technique of interfacial polymerization (IP) is used to fabricate thin film composite (TFC) membranes. In experiments here, microporous polypropylene (PP) flat film membranes were used as a support for fabricating TFC membranes for reverse osmosis by the IP technique. Substantial chemical, pH, and solvent resistance is provided by porous polypropylene membranes. Therefore, it is reasonable to choose porous polypropylene membranes as supports to fabricate TFC membranes for reverse osmosis.

The external and the pore surfaces of polypropylene flat film membrane were hydrophilized first by pre-wetting with acetone, then oxidized with chromic acid solution kept at 65°C. Next, the …

Preparation And Electrochemical Performance Of Three-Dimensional Porous Snco Alloy Electrode, Lian-Jie Xue, Ling Huang, Fu-Sheng Ke, Guo-Zhen Wei, Xiao-Mei Zheng, Jun-Tao Li, Xiao-Yong Fan, Shi-Gang Sun

Journal of Electrochemistry

Three-dimensional porous Cu film was prepared by electroless plating,and used as a current collector for preparation of three-dimensional structured SnCo alloy electrode,which was mainly prepared by an electrodeposition method,and composed of pure Sn and CoSn₂ phases. Electrochemical experimental results show that three-dimensional structured SnCo alloy electrode exhibits much better cycleability than planar SnCo alloy electrode,with first discharge capacity and charge capacity of 636. 3 and 528. 7 mAh·g^-1,respectively. After 70^th cycling,capacity retention is 83. 1% with 529. 5 mAh·g^-1. The lithiation process during first discharge was investigated by electrochemical impedance spectroscopy.

Research On Electrochemical Performance Of Lithium-Ion Battery Cathode Material Lini(1/3)Co(1/3)Mn(1/3)O2 In Aqueous Lino3 Solution, Jun Zheng, Xin Jia, Chong Wang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The cathode material of LiNi_1/3Co_1/3Mn_1/3O₂ synthesized by sol-gel method shows excellent high rate performance, and high output power density during discharge process. A well-ordered layered α-NaFeO₂ structure was confirmed by XRD and a primary particle size of about 500 nm was indicated by SEM. Galvanostatic charge-discharge test indicates that LiNi_1/3Co_1/3Mn_1/3O₂ in 2 mol·L^-1 LiNO₃ aqueous solution with pH 12 reached a ca-pacity of 147 mAh/g while charged and discharged at 2C. The capacities were 64, 33, 16 mAh/g with 80C (14.4 A/g), 150C …

Fabrication Of Electrochemically Activated Glassy Carbon/Bismuth Film Electrodes For Sensitive Analysis Of Pb(2+) And Cd(2+), Kang Shi, Wen-Jing Wang, Kun Hu

Journal of Electrochemistry

The application of electrochemically activated glassy carbon (GC) in the in-situ preparing of bismuth film electrodes (BiFEs) to analyze Pb^{2 +} and Cd^{2 +} was investigated. The glassy carbon electrodes were electrochemically activated by either potentiostic or cyclic polarization in 1 mol·L^-1 NaOH solution. Experimental results show that employment of HCl solution as the analytical solution not only can reproducibly renew the electrochemically activated GC electrode surface with an electrochemical clear procedure, but also can greatly enhance the sensitivity of BiFes method for analysis of Pb^{2 +} and Cd^{2 +}. The test range thus …

Preparation And Application Of Ti/Ceo2-F-Pbo2 Electrode In Electrochemical Degradation Of Organics, Xun-Hua Wang, Tie-Ming Zhang, Shao-Ping Tong, Chun-An Ma

Journal of Electrochemistry

The CeO₂-modified PbO₂ on Ti plate (Ti/CeO₂-F-PbO₂) was prepared by electrodeposition. The SEM and XRD analyses indicated that the CeO₂ particle could be beuniformly co-deposited in the film of PbO₂. The results of electrochemical test showed that the Ti/CeO₂-F-PbO₂ anode had higher potential (1.83 V. vs. SCE) for oxygen evolution (OE) than the Ti/F-PbO₂ anode (1.78 V,vs. SCE). The degradation of 4-chlorophenol was carried out to test electrocatalytic performance of this novel electrode, which indicated that Ti/CeO₂-F-PbO₂ anode had high COD removal rate …

Failure Reaction Mechanism Of Internal Short-Circuit For Lithium-Ion Batteries, He Li, Shen-Jun Yu, Zhi-Kui Chen, Guang-Chuan Liang

Journal of Electrochemistry

In this work, the battery impact testing machine has been used to study the failure progress of internal short-circuit (ISC) for lithium ion batteries. The reaction mechanisms between cathode/anode and electrolyte in the battery at different temperatures were characterized by differential scanning calorimetry (DSC), gas chromatography/mass spectrometry (GC/MS) and X-ray diffraction (XRD). The experimental results show that the ISC failure of the battery was mainly due to the reaction between cathode Li_0.5CoO₂ and electrolyte. The decomposition and oxygen evolution reactions of cathode occurred when the temperature reached a certain value. At the same time a fierce oxidation …

Electrochemical Behaviors Of Hydrazine In Bmimpf6 Solution At Ag Electrode, Jie Sun, Yan Li, Yi-Ling Feng, Rong Wang, Xia-Qin Wu

Journal of Electrochemistry

In this work, the electrochemical behaviors of hydrazine at Ag electrode in the room temperature ionic liquid, BmimPF₆, were studied by cyclic voltammetry. Results suggested that Ag electrode showed a good catalytic activity towards hydrazine oxidation. The catalytic peak current showed a good linear relationship with the hydrazine concentration in the range of 0 ～ 3.4 mmol/L. The rate-determining step of the electrocatalytic reaction involved one electron transfer form hydrazine molecule to Ag⁺ ion.

Synthesis And Electrochemical Properties Of Li3V2(Po4)3/C Cathode Materials For Lithium Ion Battery, Li-Ying Liu, Hai-Yan Zhang, Lian Chen, Yu-Chun Zhai

Journal of Electrochemistry

Cathode material Li₃V₂(PO₄) ₃ /C for Lithium-ion battery was synthesized by combination of ball milling and baking. Physical and electrochemical performances of as-prepared materials were characterized through XRD,EIS and galvanostatic cell cycling. The results show that the products were monoclinic Li₃ V₂ (PO₄) ₃ with well-developed crystal structure. At 0. 1C,0. 25C and 0. 5C,the initial discharge capacities were 150. 6,134. 1 and 107. 1 mAh·g^-1 ,respectively. Capacity retention rates were 87. 3% after 130 cycles at 0. 25C and 87. 2% after 105 cycles at 0. 5C. Charge-discharge …

Optimization Of Membrane Electrode Assembly In Air-Breathing Direct Methanol Fuel Cell, Liang Ma, Wei-Wei Cai, Jing Zhang, Liang Liang, Jian-Hui Liao, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

The structure and performance of MEA were optimized by tailoring the catalyst layer,cathodic microporous layer (MPL) ,anodic MPL and membrane,with the considerations of unique characteristics of airbreathing direct methanol fuel cell (DMFC) such as methanol crossover and cathode flooding. It was found that high catalyst loading could suppress the methanol crossover effectively,but too high catalyst loading can lead to high mass transport resistance. Hydrophobic anodic MPL with 30% (by mass) PTFE could facilitate the CO₂ bubble detachment,which decreased the methanol concentration gradient and suppressed the methanol crossover accordingly. When Nafion 115 was used as membrane,methanol crossover was severe,while Nafion …

A High Performance Sulfur/Carbon Xerogel Composite In Lithium Sulfur Battery Application, Chong Wang, Jia-Jia Chen, Qiu-Jie She, Qian Zhang, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Sulfur/carbon composite was synthesized by the thermal method with the carbon xerogel as the conductive framework. The property of composite was characterd by XRD and SEM. It shown that the composite with the particle size below 10 μm had the same morphology as the carbon xerogel and the sulfur was absorbed in the pores in non-crystalline. The discharge capacity of the composites were 1311 mAh/g and 1107. 1 mAh/g at 0. 1C and 0. 2 C rates,respetively. And a retention capacity was about 800 mAh/g after 30 cylcyes.

Nano/Micro-Structured Electrode Materials For Lithium-Ion Batteries, Yu-Guo Guo, Zhong-Li Wang, Xing-Long Wu, Wei-Ming Zhang, Li-Jun Wan

Journal of Electrochemistry

Nanostructured materials are currently of interest as high performance anodes and cathodes for rechargeable lithium-ion batteries because of their novel nano-size effects and significantly enhanced kinetics. This review paper describes some recent developments in this field,addressing the size effects,morphology effects,as well as the functions of carbon coating layers toward lithium storage. Several"kinetically stabilized"nano/microstructured electrode materials and high-rate electrode materials with mixed-conducting networks based on the work of the authors are highlighted for illustration.