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Full-Text Articles in Materials Science and Engineering

Investigation Of The Plasma Electrolytic Oxidation Mechanism Of Titanium, Golsa Mortazavi Aug 2017

Investigation Of The Plasma Electrolytic Oxidation Mechanism Of Titanium, Golsa Mortazavi

Material Science and Engineering Dissertations - Archive

Plasma electrolytic oxidation (PEO) is an environmentally friendly technology capable of forming coatings with excellent adhesion strength at high deposition rates. The PEO process is particularly attractive for forming desirable oxide-based coatings in transition metals (Al, Ti, Mg) to improve their surface sensitive properties. At present, the PEO mechanism is not fully understood since the process includes complex processes that are difficult to study. However, understanding the PEO mechanism is essential to produce coatings with desirable characteristics for a variety of new applications. One critical PEO process parameter is the applied total current to the workpiece. The total applied current …


The Mechanism Of Radiation-Induced Nanocluster Evolution In Oxide Dispersion Strengthened And Ferritic-Martensitic Alloys, Matthew John Swenson Aug 2017

The Mechanism Of Radiation-Induced Nanocluster Evolution In Oxide Dispersion Strengthened And Ferritic-Martensitic Alloys, Matthew John Swenson

Boise State University Theses and Dissertations

The objective of this study is to evaluate the mechanism of irradiation-induced nanoparticle evolution in a model Fe-9%Cr oxide dispersion strengthened steel and commercial ferritic-martensitic alloys HCM12A and HT9. Each alloy is irradiated with Fe2+ ions, protons, or neutrons to doses ranging from 1-100 displacements per atoms at 500°C. The morphology of nanoclusters are characterized using atom probe tomography. The evolution of clusters in each alloy are notably different with each irradiating particle, and the competing effects of ballistic dissolution and radiation-enhanced, diffusion-driven growth are attributed to the respective differences in cluster evolution. A phase evolution model, originally theorized …


Analysis And Modeling Of The Growth Of Intermetallic Compounds In Aluminum–Steel Joints, Gang Zhang, Manjiao Chen, Yu Shi, Jiankang Huang, Fuqian Yang Aug 2017

Analysis And Modeling Of The Growth Of Intermetallic Compounds In Aluminum–Steel Joints, Gang Zhang, Manjiao Chen, Yu Shi, Jiankang Huang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this work, we experimentally and numerically studied the microstructures and growth of intermetallic compounds (IMCs) formed in Al–Fe (aluminum–steel) joints welded by a pulsed double electrode gas metal arc welding (DE-GMAW)-brazing method. The IMCs consist of Fe2Al5 and FeAl3, with Fe2Al5 being the main compound in the joints. The thickness of an IMC layer increases with an increase of the welding current (heat input) into the base metal. EBSD measurement suggests that the preferred crystal orientation of the Fe2Al5 IMC likely provides the necessary path for Al atoms …


Effects Of Iron Concentration And Redox States On Failure Of Boron-Free E-Glass Fibres Under Applied Stress In Different Conditions, Qingwei Wang, Richard K. Brow, Hong Li, Erica Ann Ronchetto Aug 2017

Effects Of Iron Concentration And Redox States On Failure Of Boron-Free E-Glass Fibres Under Applied Stress In Different Conditions, Qingwei Wang, Richard K. Brow, Hong Li, Erica Ann Ronchetto

Materials Science and Engineering Faculty Research & Creative Works

Hydrolysis resistance of boron-free E-glass fiber with different total iron oxide (Fe2O3) concentrations, iron redox index and durations of fiber ageing up to 180 days at 50◦C with 50% relative humidity (RH) was studied. The effect of ageing on the fibre failure measured in two different test environments was examined by using two-point bending method. Based on the differences in failure strains of the fibres obtained from the two conditions as a function of ageing time, the Griffith theory of solid fracture was applied to estimate glass surface energy difference in ageing conditions. The results showed …


In Situ Tem Micropillar Compression Testing In Irradiated Oxide Dispersion Strengthened Alloys, Kayla Haruko Yano Aug 2017

In Situ Tem Micropillar Compression Testing In Irradiated Oxide Dispersion Strengthened Alloys, Kayla Haruko Yano

Boise State University Theses and Dissertations

The objective of this study is to determine the validity of in situ transmission electron microscopy (TEM) micro-compression of pillars in as received and ion-irradiated Fe-9%Cr oxide dispersion strengthened (ODS) alloy. The growing role of charged particle irradiation in the evaluation of nuclear reactor candidate materials requires the development of novel methods to assess mechanical properties in near-surface irradiation damage layers just a few micrometers thick. In situ TEM mechanical testing is one such promising method, yet size effects must be understood to validate the technique. In this work, a micro-compression pillar fabrication method is developed. Yield strengths measured directly …


Testing Our Assumptions: The Role Of First Course Grade And Course Level In Mathematics And English, Janet Callahan, Marcia Belcheir Aug 2017

Testing Our Assumptions: The Role Of First Course Grade And Course Level In Mathematics And English, Janet Callahan, Marcia Belcheir

Materials Science and Engineering Faculty Publications and Presentations

Methods that provide an early indicator of factors that affect student persistence are important to colleges and universities. This quantitative research focused on the role of level of entry mathematics and English and also on grades earned in those classes as they relate to persistence after one year. The research showed that by far, the variable most predictive of first-time, full-time students enrolling one year later was earning a grade of “A” in English. Compared to those who did not pass their first English course, students who earned an “A” were three times more likely to persist. The variables which …


Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen, Larry E. Halliburton, Elizabeth M. Scherrer, K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles Aug 2017

Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen, Larry E. Halliburton, Elizabeth M. Scherrer, K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles

Faculty Publications

Electron paramagnetic resonance (EPR) is used to directly observe and characterize neutral Mg acceptors (Mg0Ga) in a β-Ga2O3 crystal. These acceptors, best considered as small polarons, are produced when the Mg-doped crystal is irradiated at or near 77 K with x rays. During the irradiation, neutral acceptors are formed when holes are trapped at singly ionized Mg acceptors (Mg−Ga). Unintentionally present Fe3+ (3d5) and Cr3+ (3d3) transition-metal ions serve as the corresponding electron traps. The hole is localized in a nonbonding p orbital on a threefold-coordinated oxygen ion …


Electrical Characterization Of Irradiated Semiconducting Amorphous Hydrogenated Boron Carbide, George Glen Peterson Aug 2017

Electrical Characterization Of Irradiated Semiconducting Amorphous Hydrogenated Boron Carbide, George Glen Peterson

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

Semiconducting amorphous partially dehydrogenated boron carbide has been explored as a neutron voltaic for operation in radiation harsh environments, such as on deep space satellites/probes. A neutron voltaic device could also be used as a solid state neutron radiation detector to provide immediate alerts for radiation workers/students, as opposed to the passive dosimetry badges utilized today. Understanding how the irradiation environment effects the electrical properties of semiconducting amorphous partially dehydrogenated boron carbide is important to predicting the stability of these devices in operation. p-n heterojunction diodes were formed from the synthesis of semiconducting amorphous partially dehydrogenated boron carbide on silicon …


Study Of Iron Ion Transit Through Three-Fold Channel Of Ferritin Cage, Shah Alam Limon Aug 2017

Study Of Iron Ion Transit Through Three-Fold Channel Of Ferritin Cage, Shah Alam Limon

Graduate Theses/Dissertations

Ferritin is an iron-storage globular protein with an ability to uptake, mineralize and release iron ions in a controllable manner. The globular hollow shell allows storage of mineralized iron, with several channels responsible for the transit of ions into the shell and out of it. Understanding of the detailed molecular functioning of ferritin is required for rational design of biomimetic conjugate nano-biosystems containing ferritin-like constituents. In this work, ferritin was investigated both numerically by all-atom molecular dynamics (MD) simulations, and experimentally by Raman spectroscopy. Molecular dynamic simulations of a model system comprising iron ions (Fe2+) and a ferritin trimer expressing …


On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan Aug 2017

On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan

Faculty Publications

We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering-gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the …


Molecular Dynamics Modeling And Simulation Of Bitumen Chemical Aging, Farshad Fallah Jul 2017

Molecular Dynamics Modeling And Simulation Of Bitumen Chemical Aging, Farshad Fallah

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

Chemical aging of asphalt binder leads to significant changes in its mechanical and rheological properties, resulting in poor pavement behavior and distress. Various laboratory methods have been used to simulate asphalt aging during the service life of the pavement. However, controversy exists regarding the capability of these methods to predict field aging, as various factors interact with the pavement during service and the mechanism behind aging is not fully understood. The two main outcomes of chemical aging are oxidation of asphalt molecules, and change in asphalt SARA (saturate, aromatic, resin, and asphaltene) fractions. Reaction of oxygen with asphalt components forms …


The Strength Of Moulding Sand Consisting Of A Mixture Of Bentonite, Tapioca Flour, And Sago Flour As A New Binder Formula To Improve The Quality Of Al-Si Cast Alloy, Andoko Andoko, Riana Nurmalasari, M. Alfian Mizar, Retno Wulandari, Poppy Puspitasari, Avita Ayu Permanasari Jul 2017

The Strength Of Moulding Sand Consisting Of A Mixture Of Bentonite, Tapioca Flour, And Sago Flour As A New Binder Formula To Improve The Quality Of Al-Si Cast Alloy, Andoko Andoko, Riana Nurmalasari, M. Alfian Mizar, Retno Wulandari, Poppy Puspitasari, Avita Ayu Permanasari

Journal of Mechanical Engineering Science and Technology (JMEST)

The major factors determining the quality of sand casting products are the base sand and the composition of the sand mould and the binding material. In the foundry industry, the most commonly used binder for creating sand moulds is bentonite. However, the price of bentonite is likely to keep rising. This study aimed at discovering a new binder formula associated with the effect of binder composition i.e. bentonite, tapioca flour, and sago flour on the basis of its mechanical and physical properties. The new formula was expected to be a better binder in the production of sand moulds, resulting in …


Analysis Of Strength Of Glass Fibre Composite Leaf Spring Using Finite Element Method, Andoko Andoko, Poppy Puspitasari, Avita Ayu Permanasari Jul 2017

Analysis Of Strength Of Glass Fibre Composite Leaf Spring Using Finite Element Method, Andoko Andoko, Poppy Puspitasari, Avita Ayu Permanasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Leaf spring, as one of the main components of the suspension system, serves the function of absorbing road shocks and any wheel vibrations, preventing them from being transmitted directly to the vehicle body. Moreover, it can increase the tire traction as well as support the weight of the vehicle and various kinds of external forces. Various studies on the use of composite materials for leaf springs have shown that the strength of composite leaf spring is similar to steel leaf spring with the same load carrying capacity. However, the composite leaf spring has the added advantage of being more lightweight. …


Factors Affecting The Surface Roughness In Sinking Edm Process, Ahmad Atif Fikri, Maftuchin Romlie, Aminnudin Aminnudin Jul 2017

Factors Affecting The Surface Roughness In Sinking Edm Process, Ahmad Atif Fikri, Maftuchin Romlie, Aminnudin Aminnudin

Journal of Mechanical Engineering Science and Technology (JMEST)

The purpose of this study is to gain insights into the surface quality (smoothness) of sinking EDM machining products. Among other non-conventional machining processes, Electrical Discharge Machining (EDM) is the most commonly used process. EDM is a machining process that uses electric sparks created between a workpiece and a tool (electrode). As a manufacturing process, EDM is used for workpieces which have intricate contours and precise dimensions, and works by using electric discharges (sparks) applied in a rapid series of repetitive electrical discharges between the two electrodes, separated by a dielectric fluid, and subject to an electric voltage. Since the …


Effect Of Magnetic Field On Diesel Engine Power Fuelled With Jatropha-Diesel Oil, Sukarni Sukarni, Partono Partono, Deni Krisdianto, Retno Wulandari Jul 2017

Effect Of Magnetic Field On Diesel Engine Power Fuelled With Jatropha-Diesel Oil, Sukarni Sukarni, Partono Partono, Deni Krisdianto, Retno Wulandari

Journal of Mechanical Engineering Science and Technology (JMEST)

Jatropha oil has characteristics very close to the diesel fuel, so it has good prospects as a substitute or as a mixture of diesel fuel. Previous research showed that jatropha oil usage in diesel engines caused power to decrease. It was probably owing to the higher viscosity of the Jatropha oil compared to that of diesel oil. Installing the magnetic field in the fuel line of a diesel engine fueled with jatropha-diesel oil is expected to reduce the viscosity of jatropha-diesel oil mixture, hence improve the combustion reaction process. This research aims to know the influence of the magnetic field …


Optimum Conditions For Eor Using Nanofluids Subjected To Em Waves, Muhammad Kashif, Poppy Puspitasari Jul 2017

Optimum Conditions For Eor Using Nanofluids Subjected To Em Waves, Muhammad Kashif, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Today’s major challenge for oil industry is to improve the oil recovery from the reservoir. Various enhanced oil recovery (EOR) methods have been applied in the field and the steam injection is one of the most favourable methods. The deep reservoir will result in failure of this method due to excessive heat dissipation. In this situation, generating and injecting steam may be uneconomical due to the tremendous reduction of the recovery. Some methods using nanotechnology have been introduced and elaborated. However, we propose the electromagnetic (EM) method as an alternative due to its long range transmission of the transverse waves. …


Analysis Of Biodegradation Of Bioplastics Made Of Cassava Starch, Nanang Eko Wahyuningtiyas, Heru Suryanto Jul 2017

Analysis Of Biodegradation Of Bioplastics Made Of Cassava Starch, Nanang Eko Wahyuningtiyas, Heru Suryanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Environmental pollution due to plastic waste taking too long to decompose has become a global problem. There have been numerous solutions proposed, one of which is the use of bioplastics. The use of cassava starch as the main ingredient in the manufacture of bioplastics shows great potential, since Indonesia has a diverse range of starch-producing plants. The aim of the present study is to analyse the effect of glycerol on microbial degradation. This experimental research investigated the use of cassava flour mixed with glycerol plasticizer at various concentrations (0, 2, 2.5, 3%) in the synthesis of bioplastics. The aspects studied …


Utilization Of Carbon Nanotubes In Electromagnetic Wave Detectors, Muhammad Hanis Zakariah, Poppy Puspitasari Jul 2017

Utilization Of Carbon Nanotubes In Electromagnetic Wave Detectors, Muhammad Hanis Zakariah, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

Direct detection of hydrocarbon by an active source using electromagnetic (EM) energy termed seabed logging (SBL) has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges include sensitivity and frequency matching. This paper presents development of the carbon nanotubes (CNTs) as electromagnetic wave detector due to outstanding properties of carbon nanotubes. They are currently one of the desired materials for advanced technologies. Two types of detectors were developed in this work, carbon nanotube-based (D1) and without nanotubebased (D2) detectors. Various configuration and arrangement for each type of detector were investigated to determine the one …


Glucose Recovery From Different Corn Stover Fractions Using Dilute Acid And Alkaline Pretreatment Techniques, D. Aboagye, N. Banadda, R. Kambugu, Jeffrey Seay, N. Kiggundu, A. Zziwa, I. Kabenge Jul 2017

Glucose Recovery From Different Corn Stover Fractions Using Dilute Acid And Alkaline Pretreatment Techniques, D. Aboagye, N. Banadda, R. Kambugu, Jeffrey Seay, N. Kiggundu, A. Zziwa, I. Kabenge

Chemical and Materials Engineering Faculty Publications

Background: Limited availability of corn stover due to the competing uses (organic manure, animal feed, bio-materials, and bioenergy) presents a major concern for its future in the bio-economy. Furthermore, biomass research has exhibited different results due to the differences in the supply of enzymes and dissimilar analytical methods. The effect of the two leading pretreatment techniques (dilute acid and alkaline) on glucose yield from three corn stover fractions (cob, stalk, and leaf) sourced from a single harvest in Uganda were studied at temperatures 100, 120, 140, and 160 °C over reaction times of 5, 10, 30, and 60 min.

Results: …


Suppression Of Magnetism In Ba5Alir2O11: Interplay Of Hund's Coupling, Molecular Orbitals, And Spin-Orbit Interaction, Sergey V. Streltsov, Gang Cao, Daniel I. Khomskii Jul 2017

Suppression Of Magnetism In Ba5Alir2O11: Interplay Of Hund's Coupling, Molecular Orbitals, And Spin-Orbit Interaction, Sergey V. Streltsov, Gang Cao, Daniel I. Khomskii

Center for Advanced Materials Faculty Publications

The electronic and magnetic properties of Ba5AlIr2O11 containing Ir-Ir dimers are investigated using the generalized gradient approximation (GGA) and GGA + spin-orbit coupling (SOC) calculations. We found that the strong suppression of the magnetic moment in this compound recently found by Terzic et al. [Phys. Rev. B 91, 235147 (2015)] is not due to charge ordering but is related to the joint effect of the spin-orbit interaction and strong covalency, resulting in the formation of metal-metal bonds. They conspire and act against the intraatomic Hund's rule exchange interaction to reduce total magnetic moment of the …


An Evaluation Of The Efficiency Of Compartmented Alginate Fibres Encapsulating Rejuvenator As Asphalt Pavement Healing System, Amir Tabakovic, Luke Schuyffel, Aleksandar Karac, Erik Schlangen Jul 2017

An Evaluation Of The Efficiency Of Compartmented Alginate Fibres Encapsulating Rejuvenator As Asphalt Pavement Healing System, Amir Tabakovic, Luke Schuyffel, Aleksandar Karac, Erik Schlangen

Articles

This paper explores the potential methods for evaluating a healing system for asphalt pavements. The healing system under investigation involves compartmented calcium-alginate fibres encapsulating an asphalt binder healing agent (rejuvenator). This system presents a novel method of incorporating rejuvenators into asphalt pavement mixtures. The compartmented fibres are used to distribute the rejuvenator throughout the pavement mixture, thereby overcoming some of the problems associated with alternate asphalt pavement healing methods, i.e., spherical capsules and hollow fibres. The asphalt healing efficiency methods to be evaluated in this paper include: (i) standard test methods for asphalt pavements, such as the Indirect Tensile Strength …


Real-Time Sensing Of Single-Ligand Delivery With Nanoaperture-Integrated Microfluidic Devices, W. Elliott Martin, Ning Ge, Bernadeta R. Srijanto, Emily Furnish, C. Patrick Collier, Christine A. Trinkle, Christopher I. Richards Jul 2017

Real-Time Sensing Of Single-Ligand Delivery With Nanoaperture-Integrated Microfluidic Devices, W. Elliott Martin, Ning Ge, Bernadeta R. Srijanto, Emily Furnish, C. Patrick Collier, Christine A. Trinkle, Christopher I. Richards

Chemistry Faculty Publications

The measurement of biological events on the surface of live cells at the single-molecule level is complicated by several factors including high protein densities that are incompatible with single-molecule imaging, cellular autofluorescence, and protein mobility on the cell surface. Here, we fabricated a device composed of an array of nanoscale apertures coupled with a microfluidic delivery system to quantify single-ligand interactions with proteins on the cell surface. We cultured live cells directly on the device and isolated individual epidermal growth factor receptors (EGFRs) in the apertures while delivering fluorescently labeled epidermal growth factor. We observed single ligands binding to EGFRs, …


Ismar / Rmcmr 2017 Abstract Book - Joint Conference Of The International Society Of Magnetic Resonance, The Rocky Mountain Conference On Epr, And The Rocky Mountain Conference On Magnetic Resonance Jul 2017

Ismar / Rmcmr 2017 Abstract Book - Joint Conference Of The International Society Of Magnetic Resonance, The Rocky Mountain Conference On Epr, And The Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Abstracts from the 59th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, hosted jointly with the International Society of Magnetic Resonance and the Rocky Mountain Conference on EPR. Held in Quebec City, Canada, July 23-28, 2017.


Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross Jul 2017

Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross

Faculty Publications

Results of a method of estimating index of refraction from passive, polarimetric hyperspectral imaging radiance measurements are presented. As off-nadir viewing hyperspectral imaging platforms gain prominence, estimating index of refraction, which is invariant to viewing angle, may prove advantageous to estimating the emissivity, which is not. Results show that index of refraction can be retrieved to within 8% rms error for fused silica and sapphire glass targets, while simultaneously estimating object temperature. The accuracy and self-consistency of this technique for estimating index of refraction are shown to compare favorably to the maximum smoothness temperature–emissivity separation algorithm. Additionally, the results show …


Fabricating Ordered 2-D Nano-Structured Arrays Using Nanosphere Lithography, Chenlong Zhang, Sandra Cvetanovic, Joshua M. Pearce Jul 2017

Fabricating Ordered 2-D Nano-Structured Arrays Using Nanosphere Lithography, Chenlong Zhang, Sandra Cvetanovic, Joshua M. Pearce

Department of Materials Science and Engineering Publications

Recent advances in the use of plasmonic metamaterials to improve absorption of light in thin-film solar photovoltaic devices has created a demand for a scalable method of patterning large areas with metal nanostructures deposited in an ordered array. This article describes two methods of fabricating ordered 2D nanosphere colloidal films: spin coating and interface coating. The two methods are compared and parameter optimization discussed. The study reveals that:

• For smaller nanosphere sizes, spin coating is more favorable, while for larger nanospheres, the angled interface coating provides more coverage and uniformity.

• A surfactant-free approach for interface coating is developed …


Comparison Between Single Loading–Unloading Indentation And Continuous Stiffness Indentation, Yun-Fei Jia, Yuan-Yuan Cui, Fu-Zhen Xuan, Fuqian Yang Jul 2017

Comparison Between Single Loading–Unloading Indentation And Continuous Stiffness Indentation, Yun-Fei Jia, Yuan-Yuan Cui, Fu-Zhen Xuan, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Experiments are performed on fused silica, Si, and duplex stainless steel to examine whether the CSM (continuous stiffness indentation) method will provide approximately the “same” results of contact modulus and indentation hardness as those measured from the quasi-static single loading–unloading indentation. The experimental results show that the elastic modulus measured by the CSM method is compatible with that by the quasi-static loading–unloading method for hard materials, while there exists a percentage difference of ∼21.3% between the smallest value and the largest vale of the measured indentation hardnesses from the CSM method for fused silica and a percentage difference of ∼15.3% …


Graphite And Graphene-Oxide Based Pgm-Free Model Catalysts For The Oxygen Reduction Reaction, Joseph Henry Dumont Jul 2017

Graphite And Graphene-Oxide Based Pgm-Free Model Catalysts For The Oxygen Reduction Reaction, Joseph Henry Dumont

Nanoscience and Microsystems ETDs

The world currently relies heavily on fossil fuels such as coal, oil, and natural gas for its energy. Fossil fuels are non-renewable, that is, they draw on finite resources that will eventually dwindle, becoming too expensive or too environmentally damaging to retrieve. One alternative source of energy are fuel cells, electrochemical devices that convert chemical energy to cleanly and efficiently produce electricity. They can be used in a wide range of applications, including transportation, stationary, portable and emergency power sources. Their development has been slowed by the high cost of PGM electrocatalysts needed at both electrodes as well as sluggish …


Novel Durable Antimicrobial Ceramic With Embedded Copper Sub-Microparticles For A Steady-State Release Of Copper Ions, Adam J. Drelich, Jessie Miller, Robert Donofrio, Jaroslaw Drelich Jul 2017

Novel Durable Antimicrobial Ceramic With Embedded Copper Sub-Microparticles For A Steady-State Release Of Copper Ions, Adam J. Drelich, Jessie Miller, Robert Donofrio, Jaroslaw Drelich

Michigan Tech Publications, Part 1

Using pottery clay, porous ceramic stones were molded and then decorated with copper sub-microparticles inside the pores. Copper added antimicrobial functionality to the clay-based ceramic and showed ability in disinfecting water. Populations of both Staphylococcus aureus and Klebsiella pneumoniae in contaminated water were reduced by >99.9% in 3 h when exposed to an antimicrobial stone. This antimicrobial performance is attributed to a slow release of copper into water at both room and elevated temperatures. Copper is leached by water to produce ion concentrations in water at a level of 0.05–0.20 ppm after 24 to 72 h immersion tests. This concentration …


Investigating Rheological, Morphological And Mechanical Properties Of Pbs/Pbat Blends, A Boonprasertpoh, D Pentrakoon, J Junkasem Jul 2017

Investigating Rheological, Morphological And Mechanical Properties Of Pbs/Pbat Blends, A Boonprasertpoh, D Pentrakoon, J Junkasem

Journal of Metals, Materials and Minerals

Morphological, rheological and mechanical properties of various biodegradable poly(butylene succinate) (PBS)/poly(butylene adipate-co-terephthalate) (PBAT) blends via conventional melt blending technique are studied. The morphology, rheology, and tensile properties of the PBS/PBAT blends were observed by scanning electron microscope (SEM), rotational rheometer, and universal testing machine, respectively. The SEM micrographs of the PBS/PBAT blends reveal an occurrence of phase separation indicating by a presence of spherical particles/cavities for a range of 10 to 30 wt% (i.e. PBS90-PBS70), and 70 to 90 wt% (i.e. PBS30-PBS10) PBT content and co-continuous structure for a range of 40 to 60 wt% (i.e. PBS60PBS40) PBAT content. The …


Strengthening Of The Astm-356 Alloy With Silicon Carbide Particles, Jaime Hinojosa-Torres, Diego Sánchez-García, Andrés Herrera-Vázquez, Jose Luis Velázquez-Ortega Jul 2017

Strengthening Of The Astm-356 Alloy With Silicon Carbide Particles, Jaime Hinojosa-Torres, Diego Sánchez-García, Andrés Herrera-Vázquez, Jose Luis Velázquez-Ortega

Journal of Metals, Materials and Minerals

Extensive research has been done in recent years in composites of metallic matrix in order to get better melting practices, mechanical properties and structure. In this work, steel metal mould was previously preheated to three different temperatures. The ASTM-356 alloy was melted and heated to 993 K. For the purpose of reinforcing, silicon carbide particles (mesh: 325, 400) were introduced into the melted alloy then stirred. For each obtained solid its solidification time was recorded. Cylindrical specimens were tested in a tension test machine in order to obtain the ultimate tensile strength (UTS) and fracture toughness (KIc) values. Hardness measurements …