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Articles 1381 - 1410 of 3176

Full-Text Articles in Engineering Science and Materials

A Study Of The Diffusion Characteristics Of Tungsten Bar Stock And Tungsten Produced Via Direct Metal Laser Sintering (Dmls), Jonathan Robert Bruss Oct 2018

A Study Of The Diffusion Characteristics Of Tungsten Bar Stock And Tungsten Produced Via Direct Metal Laser Sintering (Dmls), Jonathan Robert Bruss

Master's Theses (2009 -)

Using a vacuum hot extraction method diffusivity and concentration of hydrogen were measured in samples of tungsten bar stock and direct metal laser sintered (DMLS) tungsten. It was found that the tungsten bar stock closely adhered to the model established by Frauenfelder. The DMLS samples approximately follow a downward sloping trend over the 500K-1200K temperature range. The trend is opposite of what is expected suggesting processing has a major effect on diffusion behavior. A CFD model was created using ANSYS Fluent to simulate the diffusion behavior. The model functions by separating out diffusion mechanisms and solving Fick’s law with each …

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Current-Driven Production Of Vortex-Antivortex Pairs In Planar Josephson Junction Arrays And Phase Cracks In Long-Range Order, Francisco Estellés-Duart, Miguel Ortuño, Andrés M. Somoza, Valerii M. Vinokur, Alex Gurevich Oct 2018

Current-Driven Production Of Vortex-Antivortex Pairs In Planar Josephson Junction Arrays And Phase Cracks In Long-Range Order, Francisco Estellés-Duart, Miguel Ortuño, Andrés M. Somoza, Valerii M. Vinokur, Alex Gurevich

Physics Faculty Publications

Proliferation of topological defects like vortices and dislocations plays a key role in the physics of systems with long-range order, particularly, superconductivity and superfluidity in thin films, plasticity of solids, and melting of atomic monolayers. Topological defects are characterized by their topological charge reflecting fundamental symmetries and conservation laws of the system. Conservation of topological charge manifests itself in extreme stability of static topological defects because destruction of a single defect requires overcoming a huge energy barrier proportional to the system size. However, the stability of driven topological defects remains largely unexplored. Here we address this issue and investigate numerically …

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Experimental Tests And Numerical Simulations For Failure Investigation On Corrugated Boxes Used On Household Appliance Packaging, Diego Fernandes Rodrigues, José Carlos Pereira Sep 2018

Experimental Tests And Numerical Simulations For Failure Investigation On Corrugated Boxes Used On Household Appliance Packaging, Diego Fernandes Rodrigues, José Carlos Pereira

Journal of Applied Packaging Research

Packages made of corrugated paper are fundamental to the protection, transportation and handling of the appliance product market. During the storage and sales stages of a product, the package must resist compressive loads in different directions beyond moderate impacts. In this context, the objective of this work is to develop and implement a post-processor that allows the simultaneous analysis of two of the most common failure modes of packages made of corrugated paper: failure due to tensile or compressive stress limit, and failure due to local buckling, when the buckling of the faces of the corrugated paper between two peaks …

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Nanoflower-Like Bi2moo6/Ag3po4 In Water Treatment, Xavier Morgan-Lange, Jaeyun Moon, Kaleab Ayalew Sep 2018

Nanoflower-Like Bi2moo6/Ag3po4 In Water Treatment, Xavier Morgan-Lange, Jaeyun Moon, Kaleab Ayalew

McNair Poster Presentations

• Environmental issues continue to intensify causing natural resources such as clean water to become increasingly scarce while demand only continues to grow. • Some of the most effective measures taken appear to be bioremediation tactics and their synthetic counterparts. • A critical area of interest are semi-conducting photocatalytic nanomaterials that take advantage of the photo-electric effect and use the introduction of ultra violet (UV) and visible light to induce oxidation and reduction reaction in p-type semiconductors. This results in the decomposition of certain pollutants and/or deactivates certain microbes in water. • These materials have the potential to operate using …

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Complex Coordination Silver Electrocrystallization Mechanism On Glassy Carbon Electrode Surface, Shuai-Shuai Huang, Cheng Liu, Lei Jin, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min. Zhou Aug 2018

Complex Coordination Silver Electrocrystallization Mechanism On Glassy Carbon Electrode Surface, Shuai-Shuai Huang, Cheng Liu, Lei Jin, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min. Zhou

Journal of Electrochemistry

Cyclic voltammetry and potential step methods were successfully used to study the electrochemical crystallization mechanism of silver deposition on glassy carbon electrode (GCE) in the practical cyanide-free silver plating electrolyte containing composite complexing agents. Scharifker-Hill (SH) theory was used to fitting the experimental data. The results showed that the electrodeposition of silver is a diffusion controlled irreversible electrode process according to three-dimensional instantaneous nucleation mechanism. When the step potential shifted from -750 mV to -825 mV, the peak deposition current Im was increased, while the induced nucleation time tm shortened. The calculated kinetic parameters showed that the diffusion coefficient (D) …

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Preparation And Characterization Of Self-Supporting Flexible Nitrogen-Doped Carbon Fabric Electrodes, Bo Yang, Zhi-Hang Jin, Ya-Ping Zhao, Zai-Sheng Cai Aug 2018

Preparation And Characterization Of Self-Supporting Flexible Nitrogen-Doped Carbon Fabric Electrodes, Bo Yang, Zhi-Hang Jin, Ya-Ping Zhao, Zai-Sheng Cai

Journal of Electrochemistry

With the wide applications of intelligent wearable devices in various fields, developing a new generation of flexible energy storage devices has become a major challenge for the current technology. As a wide application of wearable flexible substrate, cotton fabric has the advantages over low price, non-toxic and environmental friendly, but the poor conductivity becomes a major problem limiting its development. As a nitrogen-containing conducting polymer, polypyrrole is traditionally used as electrode materials, but poor mechanical performance and cycle stability severely limit its application in electrode materials. In this article, a self-supporting flexible nitrogen-doped carbon fabric electrode was prepared by in …

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Hybrid Battery-Capacitor System Based On Liti5O12 Anode And Ptpan Cathode, Xiu-Li Su, Xiao-Li Dong, Yao Liu, Yong-Gang Wang, Ai-Shui Yu Aug 2018

Hybrid Battery-Capacitor System Based On Liti5O12 Anode And Ptpan Cathode, Xiu-Li Su, Xiao-Li Dong, Yao Liu, Yong-Gang Wang, Ai-Shui Yu

Journal of Electrochemistry

Owing to its high safe, high rate and long life characteristics, lithium titanate (Li4Ti5O12) anode material has attracted extensive attention in recent years, and many efforts are being made to develop the Li4Ti5O12 based high performance hybrid supercapacitors and Li-ion batteries. Herein, we prepared the organic cathode material polytriphenylamine (PTPAn) through chemical oxidation and polymerization of triphenylamine (TPAn), and investigated its charge storage mechanism and electrode kinetics withthe typical electrochemical methods in an organic electrolyte. It was demonstrated that the PTPAn exhibited the reversible capacity of 85 mA·g-1 …

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Electrochemical Performances Of Neodymium Doped Lead Dioxide Composite Anode, Hong-Hui Wang, Ming-Jie Ma, Jie Feng, Huang-Ya Kang, Wen-Jie Huang Aug 2018

Electrochemical Performances Of Neodymium Doped Lead Dioxide Composite Anode, Hong-Hui Wang, Ming-Jie Ma, Jie Feng, Huang-Ya Kang, Wen-Jie Huang

Journal of Electrochemistry

Neodymium (Nd) doped titanium (Ti)-based lead dioxide (PbO2) composite anode was prepared by electrodeposition. The surface morphologies and crystal structures of the as-prepared anodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique, respectively. The electrochemical performances of PbO2-Nd anode were studied by electrochemical impedance spectroscopy, linear sweep voltammetry and cyclic voltammetry. Additionally, the electrocatalytic activity and durability of PbO2-Nd anode were investigated through the degradation of simulative refractory organic wastewater of phenol. The results showed that Nd doping made the PbO2 anode surface structure dense and uniform with smaller …

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Assemblies And Properties Of Asymmetric Supercapacitors Based On Wo3/Carbon Cloth, Wen-Ke Shao, Lei Zhao, Chao Liu, Yan-Ying Dong, Yuan-Jie Zhu, Qiu-Fan Wang Aug 2018

Assemblies And Properties Of Asymmetric Supercapacitors Based On Wo3/Carbon Cloth, Wen-Ke Shao, Lei Zhao, Chao Liu, Yan-Ying Dong, Yuan-Jie Zhu, Qiu-Fan Wang

Journal of Electrochemistry

The demand for a new generation of flexible, portable, and high-capacity power sources increases rapidly with the development of advanced wearable electronic devices. One dimensional (1D) nanowires structures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to their advantages in both micorstructures and their high surface areas. Here we report a simple process for large-scale fabrication of self-standing composite film electrodes composed of WO3 nanorods on carbon cloth. In order to improve the energy density of supercapacitor, we assembled an asymmetric supercapacitor using WO3 nanorods and activated carbon cloth as …

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Preparations Of Nano-Manganite Loaded Titanium Electocatalytic Membrane Electrode For Phenolic Wastewater Treatment, Le Li, Hong Wang, Rong-Hua Ma, Hong-Sen Hui, Xiao-Ping Liang, Jian-Xin Li Aug 2018

Preparations Of Nano-Manganite Loaded Titanium Electocatalytic Membrane Electrode For Phenolic Wastewater Treatment, Le Li, Hong Wang, Rong-Hua Ma, Hong-Sen Hui, Xiao-Ping Liang, Jian-Xin Li

Journal of Electrochemistry

Nano-manganese oxide loaded on titanium electrocatalytic membrane electrodes (nano-MnOx/Ti) were synthesized bysol-gel method using porous Ti membrane as a substrate and the manganese acetate as a raw material without releasing NOx. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Field-emission scanning electron microscopy (FESEM) were employed to characterize crystal form, valence state and surface morphology of nano-MnOx, respectively. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) were used to investigate the electrochemical properties of nano-MnOx electrode. The results indicated that the MnOx catalysts consisted of γ-MnO2 and Mn2 …

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Electrochemical Preparation And Photo-Electro Catalytic Properties Of Flexible Znni/Al-Ldhs/Carbon Fibers Composite, Jing-Jing Tian, Tao Chen, Xing-Chen Bao, Meng-Xu Gao, Ye-Xiao Yu, Si-Yao Peng, Guan-Ping Jin Aug 2018

Electrochemical Preparation And Photo-Electro Catalytic Properties Of Flexible Znni/Al-Ldhs/Carbon Fibers Composite, Jing-Jing Tian, Tao Chen, Xing-Chen Bao, Meng-Xu Gao, Ye-Xiao Yu, Si-Yao Peng, Guan-Ping Jin

Journal of Electrochemistry

In this work, a promising flexible composite consisting of zinc (Zn), nickel (Ni) and aluminum (Al) layered double hydroxide coated carbon fibers (ZnNi/Al-LDHs/CFs) was prepared by electrochemical method with convenient recovery and separation. The structures, morphologies, and photo-electro catalytic properties of ZnNi/Al-LDHs/CFs were characterized by X-ray diffraction, infrared spectroscopy, field emission scanning electron microscopy, inductively coupled plasma atomic emission spectrometry and electrochemical impedance spectroscopy techniques. The excellent photo-electro bifunctional catalytic properties were obtained with the ZnNi/Al-LDHs/CFs composite as compared to that of Zn/Al-LDHs/CFs (photo catalyst) or Ni/Al-LDHs/CFs (electrocatalyst) alone, which could be used in the electro-catalytic oxidations of methanol and …

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An Aqueous All-Metal Oxide Asymmetric Supercapacitor With High Gravimetric And Volumetric Energy Densities, Xin Jing, Xu Zhang, Wei Wang, Jun-Wei Lang Aug 2018

An Aqueous All-Metal Oxide Asymmetric Supercapacitor With High Gravimetric And Volumetric Energy Densities, Xin Jing, Xu Zhang, Wei Wang, Jun-Wei Lang

Journal of Electrochemistry

Only with both high gravimetric and high volumetric energy densities, can supercapacitors find more extensive applications.In this paper, by making good use of the interesting nanostructures and the high packing densities of RuO2 (nanoshpheres,1.69 g·cm-3) and Co-Ni oxide (nanoflakes, 2.14 g·cm-3), the RuO2//KOH//Co-Ni oxide all-metal oxide asymmetric supercapacitors with high performance were successfully fabricated, which led to the maximum specific capacitance of 217.5 F·g-1 (412.3 F·cm-3) and specific energy density of 61.8 Wh·kg-1 (121 Wh·L-1) in a cell voltage between 0 and 1.5 V in KOH electrolyte. …

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Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang Aug 2018

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

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Influences Of Na-Mn Ratio On Electrochemical Performances And Intercalation-Deintercalation Processes Of Sodium Ion In NaXMno2, Yong-Chun Xie, Cheng Wang, Fang Jiang, Yang Yang, Jing Su, Yun-Fei Long, Yan-Xuan Wen Aug 2018

Influences Of Na-Mn Ratio On Electrochemical Performances And Intercalation-Deintercalation Processes Of Sodium Ion In NaXMno2, Yong-Chun Xie, Cheng Wang, Fang Jiang, Yang Yang, Jing Su, Yun-Fei Long, Yan-Xuan Wen

Journal of Electrochemistry

In this work, NaxMnO2 was synthesized by a solid-state reaction. The influences of Na:Mn ratio on the structure, morphology and electrochemical performance, and sodium ion intercalation/deintercalation processes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge test. The prepared NaxMnO2 was mainly composed of Na0.7MnO2 and Na0.91MnO2, and the content of Na0.91MnO2 increased with the increase of Na:Mn ratio. However, the activation energy values of surface membrane diffusion, interfacial electrochemical reaction and …

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Synthesis Of Crumpled Graphene And Titanium Dioxide Based–Nanomaterials And The Application To Carbon Dioxide Photoreduction, Yao Nie Aug 2018

Synthesis Of Crumpled Graphene And Titanium Dioxide Based–Nanomaterials And The Application To Carbon Dioxide Photoreduction, Yao Nie

McKelvey School of Engineering Graduate Student Theses & Dissertations

With the rapid development of the economy, increasing combustion of fossils fuels has caused an increase in the atmospheric carbon dioxide (CO2) level, and has led to global climate change. As a mitigation approach, CO2 capture and conversion (CCC) can not only capture CO2, but also convert it to useable products, such as hydrocarbon fuels. Photocatalytic reduction is an attractive CCC option that directly harnesses inexpensive and abundant solar energy. Titanium dioxide (TiO2) is a widely used semiconductor for photocatalysis, and graphene nanosheets are a promising material for use in fabricating graphene-TiO2 hybridized photocatalysts. To realize the application of these …

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Developing Strategies To Toughen Bio-Inspired Adhesives, Narelli P. Narciso, Samuel Lee Huntington, Jonathan J. Wilker Aug 2018

Developing Strategies To Toughen Bio-Inspired Adhesives, Narelli P. Narciso, Samuel Lee Huntington, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Mussels and other marine creatures adhere very well in underwater environments, having the ability to withstand the force of the sea. These animals have inspired synthetic biomimetic adhesives for wet systems, presenting potential for biomedical applications. However, most current commercial adhesives tend to be brittle, not resisting repetitive movements. This study assesses toughening strategies to improve the mussel-inspired adhesives’ ductility while maintaining its strength. The strategies included altering the polymer’s chemical structure by changing the percentage of polyethylene glycol (PEG) in the molecule and by adding fillers, such as calcium carbonate, silica and nacre - a calcium carbonate compound found …

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Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys., Lars Herhold Aug 2018

Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys., Lars Herhold

Electronic Theses and Dissertations

Additive Manufacturing (AM) with metals has been accomplished mainly through powder bed fusion processes. Initial experiments and simulations using Material Extrusion Additive Manufacturing (MEAM) have been performed by various researchers especially using low melting alloys. Recently Stratasys Inc. submitted a patent application for the use of their Material Extrusion technology also called Fused Deposition Modeling (FDM) where they describe the process using thixotropic semi-solid alloys. Currently this process using semi-solid, engineering type alloys such as A356 or THIXALLOY 540 aluminum have not been researched to evaluate the control parameters. This research combines the in-depth knowledge of applying thixotropic semi-solid aluminum …

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The Effect Of Rotational Speed, Friction Duration, And Pressure On Tensile Strength Of Aisi 6061 Welding Joints, Dewi Puspitasari, Poppy Puspitasari, M. Rizka Gita Firmansyah, Solichin Solichin Jul 2018

The Effect Of Rotational Speed, Friction Duration, And Pressure On Tensile Strength Of Aisi 6061 Welding Joints, Dewi Puspitasari, Poppy Puspitasari, M. Rizka Gita Firmansyah, Solichin Solichin

Journal of Mechanical Engineering Science and Technology (JMEST)

Electric arc welding with covered electrodes is ideally suited for flat plates. If this technique is employed for welding rigid bodies, the results would be of poor quality. One viable solution to weld rigid bodies is through friction welding. The study aimed to investigate the tensile strength of specimens subjected to friction welding with variations in rotational speed, friction time, and pressure and to examine the microstructure of friction welding joints. This research used the one-shot case study design and involved descriptive analysis. The descriptive analysis described the results of tensile testing and microstructure of welding joints. Results showed that …

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Pine Flower Waste Innovation As A Plant Based Program Augmented Reality, Ayik Bela Saputra, Imam Muhtarom, Ni’Matul Rochmaniyah, Ardhana Iswari Citra Padmi, Ika Rahmawati Jul 2018

Pine Flower Waste Innovation As A Plant Based Program Augmented Reality, Ayik Bela Saputra, Imam Muhtarom, Ni’Matul Rochmaniyah, Ardhana Iswari Citra Padmi, Ika Rahmawati

Journal of Mechanical Engineering Science and Technology (JMEST)

Indonesia one of the tropical countries in the world can not be separated from environment problems like other developing countries. One of the causes of declining environment quality is the decline of forests in Indonesia. In 2009, Indonesia’s forest area was by more than half, to about 88 million hectares. By the year 2013 the number is about 82 million hectares. One of the efforts to promote environment education is to familiarize planting plants to children from an early age from the school environment to the family environment. Therefore it is necessary an alternative in the form of planting media …

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Effect Of Mnfe2o4 Nanoparticles To Reduce Co And Hc Levels On Vehicle Exhaust Gas Emissions, Poppy Puspitasari, Sukarni Sukarni, Amir Hamzah Jul 2018

Effect Of Mnfe2o4 Nanoparticles To Reduce Co And Hc Levels On Vehicle Exhaust Gas Emissions, Poppy Puspitasari, Sukarni Sukarni, Amir Hamzah

Journal of Mechanical Engineering Science and Technology (JMEST)

The air pollution particle emitted from transportation in Indonesia Bay 2015 consist of 70.50% CO; 18.34% HC; 8.89% NOx; 0.88% SOx; 1.33%. These gases are very harmful to humans. To reduce the toxic gas effect, special treatment is needed, one of them is by applying catalyst on exhaust system. MnFe2O4 has the potential to bind the CO and HC elements contained in the exhaust gas. This study aims to investigate the effect of MnFe2O4 addition on catalityc converter towards CO gas and HC emissions of motor vehicles. Therefore, the percentage of exhaust reduction with and without applying MnFe2O4 on varied …

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Damage Simulation Of Pre-Forming V-Neck Plates With Variations In Material Type, Time And Temperature Using The Taguchi Method, Avita Ayu Permanasari, Rr. Poppy Puspitasari, Kevin Valiant Cahya, Mahfud Ihsan Jul 2018

Damage Simulation Of Pre-Forming V-Neck Plates With Variations In Material Type, Time And Temperature Using The Taguchi Method, Avita Ayu Permanasari, Rr. Poppy Puspitasari, Kevin Valiant Cahya, Mahfud Ihsan

Journal of Mechanical Engineering Science and Technology (JMEST)

In metal forming, damage can be caused by several factors: load on the workpiece, initial heating temperature, and temperature due to the friction between the die and the material for pre-forming. The metal forming process can be executed in 2 ways, namely by hot working and cold working. During these two types of mechanical working process, the metal undergoes plastic deformation. In hot working, the required deformation force is relatively low, and changes in mechanical properties are also insignificant. In cold working, a higher force is required, but the strength of the metal will increase significantly. The use of simulation …

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Mechanical Properties And Permeability Of Sand Casting Moulds With Eggshells Binder, Maryam Sharifi Jebeli Sharifi Jebeli, Wahyu Kurnianto, Wahono Wahono Jul 2018

Mechanical Properties And Permeability Of Sand Casting Moulds With Eggshells Binder, Maryam Sharifi Jebeli Sharifi Jebeli, Wahyu Kurnianto, Wahono Wahono

Journal of Mechanical Engineering Science and Technology (JMEST)

This research aimed to analyse whether or not eggshell could be a potential addition to sand mould composition as a binding material together with bentonite. Different amounts of eggshell material, i.e. 4%, 7%, 10% and 3%, were added to each sample. This study was a type of pre-experimental design called the one-shot case study. Among all sand moulds under study, sample 3 10% ES in dry conditions had the highest tensile, compressive and shear strengths of 0.09 Kg/cm2, 3.11 Kg/cm2 and 1.13 Kg/cm2, respectively. The results of the permeability test with heat treatment at 110˚C for 60 minutes showed that …

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Properties Of Cassava Starch Based Bioplastic Reinforced By Nanoclay, Nanang Eko Wahyuningtiyas, Heru Suryanto Jul 2018

Properties Of Cassava Starch Based Bioplastic Reinforced By Nanoclay, Nanang Eko Wahyuningtiyas, Heru Suryanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Synthetic Synthetic plastic is chemical materials which cause severe environmental problems. Incinerating plastic waste leads to release of hazardous gases, which is not good for humans. Bioplastic can help reduce the dependence on fossil fuels and petroleum, that bioplastic can solve the problem of synthetic plastic use. This research aims to define the properties of the cassava starch-based bioplastic reinforced by nanoclay. Methods were experimental with bioplastic component of cassava starch, glycerol as plasticizer and nanoclay as reinforcement. The bioplastic was analyzed using XRD, tensile test, moisture absorption, biodegradability, and compared with another bioplastic. The results show that the addition …

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Tunable Plasmonic Resonances In Highly Porous Nano-Bamboo Si-Au Superlattice-Type Thin Films, Ufuk Kılıç, Alyssa Mock, René Feder, Derek Sekora, Matthew J. Hilfiker, Rafal Korlacki, Eva Schubert, Christos Argyropoulos, Mathias Schubert Jul 2018

Tunable Plasmonic Resonances In Highly Porous Nano-Bamboo Si-Au Superlattice-Type Thin Films, Ufuk Kılıç, Alyssa Mock, René Feder, Derek Sekora, Matthew J. Hilfiker, Rafal Korlacki, Eva Schubert, Christos Argyropoulos, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We report on fabrication of spatially-coherent columnar plasmonic nanostructure superlattice-type thin films with high porosity and strong optical anisotropy using glancing angle deposition. Subsequent and repeated depositions of silicon and gold lead to nanometer-dimension subcolumns with controlled lengths. The superlattice-type columns resemble bamboo structures where smaller column sections of gold form junctions sandwiched between larger silicon column sections (“nano-bamboo”). We perform generalized spectroscopic ellipsometry measurements and finite element method computations to elucidate the strongly anisotropic optical properties of the highly-porous nano-bamboo structures. The occurrence of a strongly localized plasmonic mode with displacement pattern reminiscent of a dark quadrupole mode is …

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Properties Of Matter, Mike Jackson, Holly Haney Jul 2018

Properties Of Matter, Mike Jackson, Holly Haney

High School Lesson Plans

Students will investigate the relationship(s) between thermal and electrical properties of matter. First, students will use a multimeter and temperature probe to investigate the relationship between electrical resistance and temperature of an electrical resistor composed of metals. They will then graph collected data to analyze the relationship and draw a conclusion as to their relationship. They will then perform the same investigation on a thermal resistor made of a semiconducting substance and analyze that collected data. Finally, using ClaimEvidence-Reasoning (CER) structure, students will use their experimental evidence to state the similarities and differences between the electro-thermal properties of metals and …

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Interface Structure And Deformation Mechanisms Of Mg/Nb Multilayers, Xinyan Xie Jul 2018

Interface Structure And Deformation Mechanisms Of Mg/Nb Multilayers, Xinyan Xie

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

Magnesium (Mg) and its alloys, as the lightest structural materials, are very attractive for a range of weight sensitive applications, such as aircraft engine, transportation industry and so on. However, their further applications are limited due to the weak properties, such as the low strength and poor ductility. In recent years, advanced techniques aiming at the modification of the microstructures, have been developed to promote the properties of Mg and its alloys, such as modifying the texture, refining the grain size, forming the intermetallic phase, and introducing the interfaces or stacking faults into the systems. Constructing Mg/Nb multilayers, which introduces …

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Recent Progress For Fe-N-C Electrocatalysts In Alkaline Fuel Cells, Xin Deng, Heng-Quan Chen, Ye Hu, Qing-Gang He Jun 2018

Recent Progress For Fe-N-C Electrocatalysts In Alkaline Fuel Cells, Xin Deng, Heng-Quan Chen, Ye Hu, Qing-Gang He

Journal of Electrochemistry

Fuel cells are highly recommended nowadays due to their intrinsic advantages such as high energy conversion efficiency, nearly no pollution, and convenient operation. With the development of anion exchange membrane, alkaline fuel cells have gone through a renaissance thanks to their superiorities such as faster reaction kinetics, wider choices for both fuels and electrocatalysts. It is essential to find an appropriate electrocatalyst for oxygen reduction reaction (ORR) to improve the performance of alkaline fuel cells. Further commercialization of the widely used Pt-based materials has suffered from disadvantages such as scarcity and high cost. As alternatives to largely investigated Pt-based materials, …

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Pt/G-C3N4 Nanosheet For Visible Light-Induced Enhancement Of The Activity For Formic Acid Electro-Oxidation, Yong-Rong Sun, Chun-Yu Du, Guo-Kang Han, Ya-Jing Wang, Yun-Zhi Gao, Ge-Ping Yin Jun 2018

Pt/G-C3N4 Nanosheet For Visible Light-Induced Enhancement Of The Activity For Formic Acid Electro-Oxidation, Yong-Rong Sun, Chun-Yu Du, Guo-Kang Han, Ya-Jing Wang, Yun-Zhi Gao, Ge-Ping Yin

Journal of Electrochemistry

By using graphitic carbon nitride nanosheet (g-C3N4 nanosheet) as a support,Pt/g-C3N4 nanosheet catalyst was fabricated by microwave assisted polylol process. The nanoparticles size,composition,structure and optical properties of Pt/g-C3N4 nanosheet were characterized by TEM,XRD,XPS and UV-Vis diffuse reflectance spectroscopy. Comparing with the catalytic activities toward formic acid electro-oxidation under dark and visible light illumination,the superior activity of Pt/g-C3N4 nanosheet catalyst was achieved under visible light illumination. This visible light-driven enhancement in the formic acid performance could be attributed to the plasmon-induced electron-hole separation on g-C3N4 with …

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Carbon Composite Fe3O4 Nanoparticles Based Electrochemical Sensor For Hydrogen Peroxide Detection, Si-Yu Zhang, Hui-Juan Wang, Shu-Fang Li, Jian-Ying Qu Jun 2018

Carbon Composite Fe3O4 Nanoparticles Based Electrochemical Sensor For Hydrogen Peroxide Detection, Si-Yu Zhang, Hui-Juan Wang, Shu-Fang Li, Jian-Ying Qu

Journal of Electrochemistry

In this work, a novel hydrogen peroxide electrochemical sensor was constructed with ferroferric oxide (Fe3O4) magnetic nanoparticles, which demonstrated good electrocatalytic activity for hydrogen peroxide. There existed a good linear relationship between the concentration of hydrogen peroxide and the oxidation peak current in the range of 1.00 × 10-6 ~ 1.00 × 10-3 mol·L-1 (R = 0.9980) with the detection limit of 6.60 × 10-7 mol·L-1. The sensor exhibited good anti-interference ability, high reproducibility and stability.

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Simulation Of Fractal Growth On Metal Wire Electrode, Li-Feng Ding, Pei-Yuan Mao, Jun Cheng, Yu-Lan Niu, Yu-Hao Wen, Wei Chen Jun 2018

Simulation Of Fractal Growth On Metal Wire Electrode, Li-Feng Ding, Pei-Yuan Mao, Jun Cheng, Yu-Lan Niu, Yu-Hao Wen, Wei Chen

Journal of Electrochemistry

During processes of metal electrodepostion, there exist many complex morphological forms such as dendritic growing in the cathode deposited metal edge, which will seriously affect the quality of the electrodeposited product and current efficiency during machining. Investigations on dendritic crystal growing process and morphology could help controlling growth of electrolysis precipitate. In this work, Python and Matlab softwares were used, and the model of parallel electrode electrodeposition was established based on the diffusion-limited aggregation (DLA) model. By analyzing the law of fractal growth at different conditions of the particles number, probability, electrode spacing, the movement step length and orientation drift, …

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