Engineering Commons^™

Graphene Based Barrier Membrane For Gas Separation Processes, Cheng Peng

Dissertations

Novel graphene oxide (GO) flake-based composite lamellar membrane structure is being developed as a potential component of a garment for protection against chemical warfare agents (CWAs) represented here by simulants, dimethyl methyl phosphonate (DMMP) (a sarin-simulant) and 2-chloroethyl ethyl sulfide (2-CEES) (a simulant for sulfur mustard), yet allowing a high moisture transmission rate. GO flakes of dimensions 300-800 nm, 0.7-1.2 nm thickness and dispersed in an aqueous suspension are formed into a membrane by vacuum filtration on a porous polyethersulfone (PES) or poly (ether-ether-ketone) (PEEK) support membrane for noncovalent π-π interactions with GO flakes. After physical compression of such a …

Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan

Makara Journal of Technology

The melting of a phase change material (PCM) in a cavity with a gradient of hot wall inclination was simulated numerically using five models, namely, Model-A, Model-B, Model-C, Model-D, and Model-E with gradients of −2, −4, ∞, 4, and 2, respectively. The PCM was paraffin wax, which was melted using an enthalpy porosity technique with a pressure-based method. Model-A was found to be the best model. For the completion of the melting process, the models were assigned with the liquid fraction of 1. Model-A required the shortest time, followed by Model-B, Model-C, Model-E, and Model-D, respectively. Compared with Model-C, Model-A …

Recent Progress In Bifunctional Catalysts For Zinc-Air Batteries, Neng-Neng Xu, Jin-Li Qiao

Journal of Electrochemistry

Zinc-air battery has attracted great attention from researchers due to its high energy density and power density, which is expected to be widely used in energy conversion and storage. Air electrode as the core area of oxygen catalytic reaction is the focus of the entire zinc-air battery research. Recently, many research achievements have been made in non-noble metal bifunctional catalysts/electrodes with high activity, low cost and abundant species. In this review, we mainly focus on the reaction mechanism and the recent progress in non-noble metal oxide catalyst, carbon-based catalyst, and carbon-based transition metal compound composite and self-supporting electrode. In addition, …

Research Progress Of Metal-Nitrogen-Carbon Catalysts Toward Oxygen Reduction Reaction Inm Changchun Institute Of Applied Chemistry, Ming-Jun Xu, Jie Liu, Jun-Jie Ge, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

The development of highly active and stable catalysts toward oxygen reduction reaction (ORR) has been facing severe challenges. In recent years, pyrolytic M-N-C catalysts and metal-organic framework derived materials made the performance of non-noble metal catalysts greatly improved, however, the molecular and atomic level understanding in the reaction active sites and the mechanism are still lacking. Here, we summarize the recent research progress made in the Changchun Institute of Applied Chemistry. We present a microporous metal-organic-framework confined strategy toward the preferable formation of ORR catalysts. Firstly, we studied the active site and proposed a new active site structure for the …

Electrochemical Carbon Dioxide Reduction In Flow Cells, Jia Fan, Na Han, Yan-Guang Li

Journal of Electrochemistry

Electrochemical carbon dioxide reduction (CO₂RR) is an appealing approach to convert atmospheric CO₂ to value-added fuels and industrial chemicals, and may play an important role during the transition to a carbon-neutral economy. In order to make this technology commercially viable, it is essential to pursue CO₂RR in flow reactors instead of conventional H-type reactors, and to combine electrocatalyst development with system engineering. In this review, we overview the cell configurations and performance advantages of the two types of flow reactors, analyze their shortcomings, and discuss the effects of their different components including gas diffusion electrode …

Electrolyte Tailoring For Electrocatalytic Reduction Of Stable Molecules, Jin-Han Li, Fang-Yi Cheng

Journal of Electrochemistry

Reduction of stable molecules such as CO₂ and N₂ is important process in electrochemical energy conversion and storage technologies for electrofuels production. However, for the inert nature of CO₂/N₂ molecule and competitive proton reduction in conventional aqueous electrolytes, selective electrochemical carbon/nitrogen fixation suffers from high overpotential, low reaction rate and low selectivity. While addressing these issues has witnessed substantial advances in electrocatalysts, much less attention has been placed on the electrolytes, which play an important role in regulating the local environment and thus the performance of catalysts under operating conditions. Rational design of electrolytes has …

Fuel Cell Performance Of Non-Precious Metal Based Electrocatalysts, Yan-Feng Zhang, Fei Xiao, Guang-Yu Chen, Min-Hua Shao

Journal of Electrochemistry

The commercialization of proton exchange membrane fuel cells (PEMFCs) is hindered by high cost and low durability of Pt based electrocatalysts. Developing efficient and durable non-precious metal catalysts is a promising approach to addressing these conundrums. Among them, transition metals dispersed in a nitrogen (N)-doped carbon support (M-N-C) show good oxygen reduction reaction activity. This article reviews recent progress in M-N-C catalysts development, focusing on the catalysts design, membrane electrode assembly fabrication, fuel cell performance, and durability testing. Template-assisted approach is an efficient way to synthesize M-N-C materials with homogeneously dispersed single atom active site and reduced metal particles, carbides …

Electrochemical Energy Storage And Conversion Based On Organic Electrodes, Jian-Hang Huang, Xiao-Li Dong, Zhao-Wei Guo, Yuan-Yuan Ma, Yan-Rong Wang, Yong-Gang Wang

Journal of Electrochemistry

Aqueous batteries have been considered to be a competitive candidate for large-scale energy storage. However, most of aqueous batteries adopt inorganic electrode materials with metallic elements, which are based on the reversible insertion of metal ions, making their application being highly hindered by limited cycle life, environmental issue, high cost and low reserves. On the other hand, organic electrode materials offer the advantages of abundant reserves, tunable structures, renewability and environmental benignity. Furthermore, the wide internal space enables these organics to flexibly store various charge carriers. Organics have been investigated as the alternative to inorganic electrode materials. Herein, we review …

Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

The electrochemical conversion of CO₂ to chemical raw material for further utilization shows promising future to alleviate global warming and realize carbon cycle in nature, which is of great significance to the green chemistry and sustainable development. This review briefly introduces the advantages of CO₂ electrochemical reduction (CO₂ER) and its basic reaction principles, and summarizes the recent progress in a series of activity enhancement strategies based on nanosized metal catalysts. The influences of alloy effect, interface engineering, synergistic effect, surface defect engineering and support effect on the catalytic performance of nanosized metals for CO₂ER …

Research Progresses Of Copper Interconnection In Chips, Lei Jin, Jia-Qiang Yang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

In this paper, the copper interconnection technology in chip manufacturing is introduced in detail, and the essentials of acidic copper sulfate electroplating process and the mechanisms of common-used additives are reviewed. The progresses of novel additives at home and abroad are also summarized. Based on the studied achievement, the possibility of the novel copper interconnect process replacing the acidic copper electroplating is prospected.

Divergence Of The Dielectric Constant In Ultrathin Granular Metal Films Near The Percolation Threshold, H. Bakkali, E. Blanco, Samuel Lofland, M. Dominguez

College of Science & Mathematics Departmental Research

We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to the presence of tunneling conduction. In this region the dielectric constant is positive, and the electronic transport is not metallic but can be described by Jonscher's universal power law, even though there is a Drude-like response indicating the presence of free charge carriers. Only for thicker films when …

In Situ Electric-Field Study Of Surface Effects In Domain Engineered Pb(In1/2nb1/2)O3-Pb(Mg1/3nb2/3)O3-Pbtio3 Relaxor Crystals By Grazing Incidence Diffraction, Markys G. Cain, Margo Staruch, Paul Thompson, Christopher Lucas, Didier Wermeille, Yves Kayser, Burkhard Beckhoff, Samuel Lofland, Peter Finkel

College of Science & Mathematics Departmental Research

In this work, we present a grazing incidence X-ray diffraction study of the surface of a 0.24Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) [011] poled rhombohedral single crystal. The near surface microstructure (the top several tens to hundreds of unit cells) was measured in situ under an applied electric field. The strains calculated from the change in lattice parameters have been compared to the macroscopic strain measured with a strain gauge affixed to the sample surface. The depth dependence of the electrostrain at the crystal surface was investigated as a function of temperature. The analysis revealed hidden sweet spots featuring unusually high strains that were …

Effect Of Nanofiller Coating And Loading On Facial Elastomer Physical Properties, Rahmi K. Aulia

Theses & Dissertations

Current materials used for facial prostheses are far from being desirable, and improved properties with “skin-like” feel are needed. This study evaluates property changes induced by sequential additions of uncoated and hydrophobic-coated nano-SiO₂ to polydimethylsiloxane (PDMS) and compares them with those measured for conventional submicron SiO₂-filled materials. Each filler type was sequentially added to vinyl-terminated PDMS at 0%, 0.5%, 5%, 10%, and 15% by weight. Tensile, tear, Durometer hardness, translucency and viscoelastic properties were evaluated, with hardness and translucency also evaluated following 3000 hours of outdoor weathering. Results demonstrated that 15% coated nano-SiO₂-filled PDMS materials …

A Brief Bibliometric Survey On Circularly Polarized Antennas For Mobile Communication, Aniket Gunjal, Abhaya Pal Singh

Library Philosophy and Practice (e-journal)

This paper presents a database review on “Circularly Polarized Antennas for Mobile Communication” as it is the emerging technique used by mobile service provider because of having benefits over other types of antennas available.The polarization purity is now the major issue. In some cases due to cross polarization issue the antenna signal is cancelled at receiver side.So, it is necessary to have circularly polarized antenna to avoid this polarization issue because of change in phase of signal. The change in phase of signal is due to striking of wave on the obstacles and it slightly tilted from its direction causes …

Plastic Recycling In Additive Manufacturing: A Systematic Literature Review And Opportunities For The Circular Economy, Fabio A. Cruz Sanchez, Hakim Boudaoud, Mauricio Camargo, Joshua M. Pearce

Michigan Tech Publications, Part 1

The rapid technical evolution of additive manufacturing (AM) enables a new path to a circular economy using distributed recycling and production. This concept of Distributed Recycling via Additive Manufacturing (DRAM) is related to the use of recycled materials by means of mechanical recycling process in the 3D printing process chain. This paper aims to examine the current advances on thermoplastic recycling processes via additive manufacturing technologies. After proposing a closed recycling global chain for DRAM, a systematic literature review including 92 papers from 2009 to 2019 was performed using the scopus, web of science and springer databases. This work examines …

The Influence Of Surface Types Towards Run-Off Water In Urban Park, Febby Andini

International Programs

Pavements in Alun Kapuas Park constribute 63 of run off water over the capacity of the soil to infiltrate. This water will potentially causes the flooding and puddling issues.

The Applications Of Auxetic Material, Faizal Arifurrahman

International Programs

To date, increasing structural efficiency has become a main objective in material science and engineering. One focus is an auxetic material with a unique characteristic obtained by fabricating cellular forms. With its higher strength-to-weight ratio, auxetic is becoming popular in the real-world to produce products that are light but more durable. This study examines potential application of auxetic compared to that of conventional material.

Artificial Neural Network Discovery Of A Switchable Metasurface Reflector, J. R. Thompson, J. A. Burrow, P. J. Shah, Jonathan E. Slagle, E. S. Harper, A. Van Rynbach, I. Agha, M. S. Mills

Student Publications

Optical materials engineered to dynamically and selectively manipulate electromagnetic waves are essential to the future of modern optical systems. In this paper, we simulate various metasurface configurations consisting of periodic 1D bars or 2D pillars made of the ternary phase change material Ge2Sb2Te5 (GST). Dynamic switching behavior in reflectance is exploited due to a drastic refractive index change between the crystalline and amorphous states of GST. Selectivity in the reflection and transmission spectra is manipulated by tailoring the geometrical parameters of the metasurface. Due to the immense number of possible metasurface configurations, we train deep neural networks capable of exploring …

Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad

Mechanical Engineering Research Theses and Dissertations

In the last few decades, the popularity of composite and cellular materials has rapidly increased through their widespread applications in multiple engineering fields including aerospace, automotive, civil and biomedical. However, to a large extent, the success of their practical applications depends on our ability to predict their mechanical behavior by using high-fidelity mechanics models.

Micromechanical modeling of composite and cellular materials is a challenging task due to the heterogeneous nature of such materials and the interactions among various constituent phases at the microscopic level, which result in non-homogeneous deformation, strain and stress fields. Therefore, it is necessary to develop simple …

Maleic Anhydride Compatibilized Peach Waste As Filler In Polypropylene And High Density Polyethylene Biocomposites, Caralyn Wong, Stephanie Jung, Joongmin Shin, Ajay Kathuria

Master's Theses

It is estimated that roughly 103, 515 tons of peach waste is produced annually in the US. The majority of the waste is disposed of in landfills, which contributes to climate change as they release 93 million metric tons of CO₂ equivalent. Peach waste principally consists of remaining stone and seed after flesh removal. The agro-waste includes both cellulose and lignin, which can be utilized as a filler in plastic packaging to reduce carbon footprints and material cost. The objectives of this research are (1) to develop peach flour (PF)-filled biocomposites with a polyolefin matrix using maleic anhydride-g-high density …

Synthesis And Characterization Of Cobalt-Based Magnetic Nanostructures, Jacob Elkins

Material Science and Engineering Theses - Archive

Co is an attractive element in the development of nanostructured magnetic materials due to its relatively high moment (1.72-1.75 µB) and strong exchange and spin-orbit interactions, and many of these materials have potential in applications such as data recording media, hyperthermia treatments, and nanostructured permanent magnets. In this thesis, magnetic nanostructures of CoFe2O4, Co, and CoNi with controlled size, shape, composition, and crystal structure are synthesized via bottom-up wet chemical methods and their magnetic properties are systematically characterized. Additionally, nanocomposites of exchange-coupled FeCo/CoFe2O4 and Co/FeCo core-shell nanostructures with enhanced magnetizations are prepared and investigated. In order to understand the prominent …

Study Of Interdiffusion And Growth Of Intermetallic Compounds In Bimetallic Layers Of Alpha Brass And Al-Mg Alloy, Ratan Kota

Material Science and Engineering Theses - Archive

This work aims to study the formation of Inter Metallic Compounds (IMC’s) and their growth rate in Brass and Al-Mg alloy. This diffusion couple consists of four elements Aluminum, Copper, Zinc and Magnesium. Aluminum and Copper are major diffusing elements. Brass-Aluminum bimetal is an advanced structural material and used as a cladding material. This bimetal is produced by cold roll bonding and is mechanically bonded. To increase the adhesive strength of these bimetal layers, the sample is subjected to heat treatment which leads to the formation of Inter Metallic Compounds (IMC). Heat treatments are generally done above the recrystallization temperature …

An Investigation On The Corrosion Inhibition Of Brazing Cu-Ag Alloy, Hooman Rahmani

Material Science and Engineering Dissertations - Archive

Adsorption and inhibition behavior of 1,2,3-benzotriazole (BTA) and 2,5-dimercapto-1,3,4-thiadiazole (DMTD) on brazing Cu-Ag alloy was studied in deionized water using corrosion potential measurement, potentiodynamic polarization, adsorption isotherm investigation, X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). Pure Ag and pure Cu specimens were included to investigate the mere effect each component has on the alloy’s behavior along with a high copper alloy for comparison purposes. The electrochemical responses show that BTA shifts the corrosion potential of Cu to the noble direction but has the opposite effect for Ag and a mixed behavior for the Cu-Ag alloys. However, DMTD in …

Ractive Md Simulation On The Formation Of Amorphous Alumina Layer Using Atomic Layer Deposition (Ald), Yuxuan Lu

Graduate Theses/Dissertations

In this study, a systematic study has been performed by using the large-scale classical reactive molecular dynamics (MD) simulations to model the Atomic Layer Deposition (ALD) processes that generated tan ultra-thin and sub-nano meter amorphous alumina. The ALD process employed both water pulse and (Trimethyl-Aluminum) TMA precursors deposited onto the surface of an aluminum wetting layer. The study varied the sizes of the substrate and the concentrations of water/hydroxide precursors with a range of operating temperature to design the most favorable configurations for the subsequent TMA precursors to add onto. The role of crystallographic orientation of the Al wetting layer …

Development Of A Cvd Assisted Pld System For Growing Novel Materials, Sinjan Majumder

Graduate Theses/Dissertations

The fundamental step for development of novel materials like semiconductors involves stacking of layers of thin films of materials with desired properties on a particular substrate. In order to study the properties of these materials for research purposes in the laboratory, development of a clean fabrication technique is essential. PLD is a technique employed for growing thin films using laser ablation of a target material. CVD is an alternate method used to deposit solid materials from a gaseous phase. However, combining these two techniques can enhance plume, gas and laser interaction to facilitate the growth of novel materials with new …

Performance Of Pld Grown Zno Thin Film As A Thin Film Transistor, Shahidul Asif

Graduate Theses/Dissertations

The performance of ZnO thin film (grown in different parameters) as a thin film transistor (TFT) is the focus of this study. ZnO is renowned for being n-type semiconductor naturally which was utilized in fabricating a thin film transistor here. This thesis is compared the performance of ZnO thin film transistor by growing the thin film using pulsed laser deposition (PLD) on two slightly different substrates at different temperatures in an optimal 0.1 milli bar oxygen pressure which was later analyzed using other material characterization methods. The substrates were both Si (100) but had different resistivity due to different amount …

Aqueous Redox Flow Batteries With Boron Doped Diamond As An Electrode., Alex M. Bates

Electronic Theses and Dissertations

As the interest and implementation of renewable energy accelerates, so does that of grid energy storage. It is widely believed that a cost-effective energy storage technology will bring about the proliferation of renewable energy. Redox flow battery (RFB) technology represents a promising solution to cost-effective grid energy storage. Compared to other technologies, RFBs have a long lifetime, high efficiency, are non-flammable, significantly reduce cost, and separately scale power and energy. The separation of power and energy enables increased energy capacity by simply adding electrolyte volume. Of the challenges facing RFB technology, one readily apparent is the cost of the active …

Material Design, Processing, And Engineering Requirements For Magnetic Shape Memory Devices, Andrew Armstrong

Boise State University Theses and Dissertations

For magnetic shape memory (MSM) alloys, a magnetic field stimulates a shape change. We use the shape change to build devices such as micro-actuators, sensors, and microfluidic pumps. Currently, (as a novel technology,) devices suffer from some material and magnetic driver shortcomings. Here we address the issues related to operating temperature, repeatability, failure, and magnetic driver development. To increase the operating temperature of the MSM material, we alloyed Fe and Cu to Ni-Mn-Ga. We showed that the element-specific contribution to the valence electron density as parameter systematically determines the effect of each element on the variation of the martensite transformation …

Study Of New Transistor Architecture With Energy Filtering, Nnaemeka Mcdonald Eluagu

Material Science and Engineering Theses - Archive

The thermodynamic limit of the subthreshold slope to 60mV/decade at 300K forces MOSFET devices to use high supply voltages (> 0.5V) and therefore dissipate a lot of energy. This physical limitation of transistors is a direct consequence of thermal excitation of electrons. This study investigates a new transistor architecture capable of suppressing thermally excited electrons using a quantum well as an energy filter. The energy filter consists of a 2nm SiO2 tunneling barrier and a 2nm Quantum Well (QW) layer of Cr2O3 sandwiched between Ni electrodes and a channel of Si. Transistors having this QW energy filter have been fabricated …

Investigation Of High-Temperature Oxidation Resistance Mechanism Of Ceramic Coatings Via Microstructure Analysis, Yi Shen

Material Science and Engineering Dissertations - Archive

Recent developments of ceramic coatings deposited using magnetron reactive sputtering show that these films exhibited superior high-temperature oxidation resistance along with other desirable properties such as high hardness, optical transparency and good electrical conductivity. Detailed microstructure study of these films annealed to high temperatures using transmission electron microscopy (TEM) is deemed necessary as it provides an intuitive vision on the behavior of the materials at elevated temperature, which is essential to further improve their high-temperature oxidation resistance. In this study, Hf-B-Si-C-N films with various compositions that were annealed to various temperatures in both helium and air were subjected to detailed …