Materials Science and Engineering Commons^™

Husky Hand: A Low-Cost Electro-Mechanical Prosthetic Arm For The Underprivileged, Adam Robert

Thinking Matters Student Research Symposium

A continuation of a low-cost prosthetic upper limb prototype design which was investigated in EGN 301. The prosthetic is specifically designed for the needs and requirements of under privileged individuals in the Dominican Republic with upper limb amputations. The project focuses on the creation of an open-source computer aided prosthetic hand/arm model. The design allows consumer-grade fused filament fabrication (FFF) 3-D printers to be used. The improved design allows for the integration of the PQ-12 linear actuator for grasp and finger control. This simplifies the assembly, while, also reducing the size and mass of the whole unit. Producing a low-cost …

Finite Element Analysis Of Impact Resistant Composites Inspired By Peacock Mantis Shrimp, Nandati Shrestha

Thinking Matters Student Research Symposium

The fist-like club of the peacock mantis shrimp, a 5-inch marine crustacean, can strike its prey with speed faster than a .22-caliber bullet with an impact force more than 1,000 times its own weight. Although these creatures punch so fast that it even boils the water, they don’t take any damage. This incredible insusceptibility is due to the arrangement of mineralized fiber layers in which each fibrous layer is laid at a slightly rotated angle to form a helicoidal structure that acts as a shock absorber for the club. The goal is to perform a finite element analysis to investigate …

Pd-Based Electrocatalysts For Oxygen Reduction And Ethanol Oxidation Reactions: Some Recent Insights Into Structures And Mechanisms, Zhi-Peng Wu, Chuan-Jian Zhong

Journal of Electrochemistry

The development of efficient electrocatalysts for applications in fuel cells, including proton-exchange membrane fuel cell (PEMFC) and direct ethanol fuel cell (DEFC), has attracted extensive research attention in recent years. Oxygen reduction reaction and ethanol oxidation reaction are two of the key reactions where the design of active, stable and low-cost electrocatalysts is critical for the mass commercializations of PEMFCs and DEFCs. This challenge stems largely from the limited understanding of the catalyst structures and reaction mechanisms. Progress has been made in investigations of electrocatalysts derived from Pd-based alloy nanomaterials both experimentally and computationally. We highlight herein some of the …

Electrochemical Surface-Enhanced Raman Spectroscopic Studies On Nickel Ultramicroelectrode, Li-Wen Wu, Wei Wang, Yi-Fan Huang

Journal of Electrochemistry

Nickel (Ni) electrodes are widely used in electrochemical researches. Understanding electrochemical processes on Ni electrodes through in-situ characterization of adsorbed species on their surfaces is helpful for rational optimization and application of Ni electrochemistry. Microelectrochemical surface-enhanced Raman spectroscopy (μEC-SERS) combines the mass transfer feature of ultramicroelectrode with high-sensitivity characterizations of molecular structures, which is a powerful method for studying Ni electrochemistry on polarization and non-equilibrium conditions. The key point of performing μEC-SERS is to make a SERS-active Ni ultramicroelectrode.
Here, we demonstrate a method of preparing a SERS-active Ni ultramicroelectrode through electrochemical deposition of several atomic layers of …

Theoretical Studies Of Metal-N-C For Oxygen Reduction And Hydrogen Evolution Reactions In Acid And Alkaline Solutions, Xue-Ping Qin, Shang-Qian Zhu, Lu-Lu Zhang, Shu-Hui Sun, Min-Hua Shao

Journal of Electrochemistry

Single atom catalysts (SAC) have been regarded as the promising alternatives to platinum group metals due to their low costs and potentially high catalytic activities in various electrocatalytic reactions. The atomic mechanism understanding of activity discrepancy among different metal and nitrogen co-doped carbon-based catalysts is still lacking. Here, non-precious metal and nitrogen co-doped carbons (Me-N-C, Me = Fe and Co) as the model catalysts are investigated by combining experimental and theoretical studies to explore the catalytic activities and corresponding reaction mechanisms toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at universal pHs. Atomic theoretical simulations suggest that Fe-N-C …

Electrochemiluminescence Imaging Hydrogen Evolution Reaction On Single Platinum Nanoparticles Using A Bipolar Nanoelectrode Array, Xiang Qin, Zhong-Qiu Li, Jian-Bin Pan, Jian Li, Kang Wang, Xing-Hua Xia

Journal of Electrochemistry

A high-density (5.7 × 10⁸ cm^-2) nanoelectrode array with the electrode diameter of 200 nm and the interelectrode distance of 450 nm were fabricated. The nanoelectrode array consisted of gold nanowires embedded in a porous anodic aluminum oxide (AAO) matrix, having regular nanoelectrode distribution and highly uniform nanoelectrode size. The gold nanoelectrode array was used as a closed bipolar nanoelectrode array combined with electrochemiluminescence (ECL) method to map the electrocatalytic activity of platinum nanoparticles toward hydrogen evolution reaction (HER) by modifying the catalysts on single nanoelectrodes. Results show that HER on single bipolar nanoelectrodes could be imaged …

Preparation And Characterization Of "Water-In-Salt" Polymer Electrolyte For Lithium-Ion Batteries, Xu Hou, Xin He, Jie Li

Journal of Electrochemistry

Since the development of wearable and flexible electronic products, the demand of flexible energy storage devices such as batteries and super capacitors is in urgent. To enhance the safety and cycling stability for flexible lithium-ion batteries, “water-in-salt” polymer electrolyte was prepared by introducing 21 mol·kg^-1 LiTFSI electrolyte into cross-linked polyacrylamide (PAM) after freeze-drying. A great amount of holes with the size range of 10 ~ 20 μm can be found on the surface and in the bulk of polyacrylamide, which is benefited from the freeze-drying process and acts as a great support for the electrolyte uptake. The “water-in-salt” polymer …

Oxygen-Exposure Induced Rapid Oxidation Of Spiro-Ometad In Cspbibr2 Perovskite Solar Cells, Wei-Guo Wang, Tian Bai, Gao-Fei Xue, Mei-Dan Ye

Journal of Electrochemistry

2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (Spiro-OMeTAD) is the most widely used hole transport material in perovskite solar cells (PSCs). However, its oxidation in the air takes a long time and results in the attack of perovskite by water. In this regard, we performed the oxidation process of Spiro-OMeTAD in oxygen, where perovskite can be protected from water, guaranteeing the integrity of perovskite. It was demonstrated that the champion Spiro-OMeTAD based CsPbIBr₂ PSCs after oxygen oxidation achieved a 7.19% power conversion efficiency (PCE), showing a higher PCE than 6.29% of the champion device oxidized in air. A series of electrochemical characterization methods were applied …

Application Of Atomically Precise Metal Nanoclusters In Electrocatalysis, Zhi-Hua Zhuang, Wei Chen

Journal of Electrochemistry

Metal nanoclusters (M NCs) consist of only several to a few hundred of metal atoms and possess core sizes less than 2 nm. Owing to the quantum size effect, the electronic states of M NCs evolve to discrete levels similar to the molecule energy gaps, other than a continuous density of states to produce plasmon characteristic of bulk metal nanoparticles (M NPs). In comparison with the conventional M NPs, M NCs exhibit dramatically unique electronic and optical properties, such as molecule-like energy gaps, strong photoluminescence and high catalytic properties, which make them promising for potential application in numerous fields, such …

Lithium Storage Performance Of Hard Carbons Anode Materials Prepared By Different Precursors, Zhen-Lang Liang, Yao Yang, Hao Li, Li-Ying Liu, Zhi-Cong Shi

Journal of Electrochemistry

Hard carbon is one of the most promising anode material for lithium ion batteries (LIBs) owing to its high stability, widespread availability, low-cost, and excellent performance. The electrochemical properties of hard carbon materials depend strongly on the type of precursors. It is, therefore, very important to choose an excellent hard carbon precursor. Polyacrylonitrile, petroleum pitch and peanut shells were used as raw materials to prepare different hard carbon anode materials for LIBs. These hard carbon anode materials were successfully synthesized in two steps. The selected precursor was firstly carbonized at 600℃ for 1 h in argon atmosphere using heating rate …

Detection And Aggregation Of Listeria Monocytogenes Using Polyclonal Antibody Gold-Coated Magnetic Nanoshells Surface-Enhanced Raman Spectroscopy Substrates, Robert T. Busch, Farzia Karim, Yvonne Sun, H. Christopher Fry, Yuzi Liu, Chenglong Zhao, Erick S. Vasquez

Chemical and Materials Engineering Faculty Publications

Magnetic nanoshells with tailored surface chemistry can enhance bacterial detection and separation technologies. This work demonstrated a simple technique to detect, capture, and aggregate bacteria with the aid of end-functionalized polyclonal antibody gold-coated magnetic nanoshells (pAb-Lis-AuMNs) as surface-enhanced Raman spectroscopy (SERS) probes. Listeria monocytogenes were used as the pathogenic bacteria and the pAb-Lis-AuMNs, 300 nm diameter, were used as probes allowing facile magnetic separation and aggregation. An optimized covalent bioconjugation procedure between the magnetic nanoshells and the polyclonal antibody was performed at pH six via a carbodiimide crosslinking reaction. Spectroscopic and morphological characterization techniques confirmed the fabrication of stable pAb-Lis-AuMNs. …

Features Of Chloridizing Roasting Of Almalyk Mining Metallurgical Combinate Wastes, Malokhat Atamuratova, Dildora Khakimboeva, Khasan Sharipov, Zuhra Kadirova, Tulkin Shakarov

CHEMISTRY AND CHEMICAL ENGINEERING

With the aim to develop a comprehensive technology for processing Almalyk Mining Metallurgical Combinate (AMMC) wastes, the influence of chloride additives on the copper and zinc chloride volatilization process is considered. The relationship between presence of the calcium, potassium and sodium chlorides chlorinating additive on the copper and zinc chlorides sublimation from the AGMK wastes at roasting temperatures up to 700-1000˚C was established.

Synthesis Of Superabsorbing Hydrogels Based On Starch Copolymers, Baxodir Kholnazarov, Khayit Turaev, Abdulakhat Jalilov

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to synthesize highly swellable superabsorbent hydrogels based on starch copolymers. To achieve this goal, mineral-containing superabsorbent hydrogels based on starch, acrylamide, binder and initiator were synthesized. The optimal synthesis conditions were determined and studies were carried out on the influence of the molar ratios of the starting substances on the composition and physicochemical properties of the synthesized superabsorbent hydrogel. In the course of research, the optimum copolymerization temperature was 60 ° C, and the reaction time was 3 hours.

As a result of the study, a superabsorbent hydrogel based on starch, acrylamide and bentonite …

Synthesis Of Thiocol Oligomer Based On Sodium Tetrasulphide, Epichlorhydrine And Ammonium Phosphate, Bakhtiyor Normurodov, Khayit Turaev, Abdulakhat Jalilov, Sherzod Kasimov

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this study is the synthesis and study of thiokol oligomer NEP-12 brand based on sodium tetrasulfide, epichlorohydrin and ammonium phosphate, which is intended for use as a main component of Thiokol sealant. To achieve this goal, a thiokol oligomer based on sodium tetrasulfide, epichlorohydrin, and ammonium phosphate was synthesized and investigated, and the optimal conditions for the synthesis of a thiokol oligomer were determined. Research has been carried out on the influence of the molar ratios of the starting substances on the composition and physicochemical properties of the synthesized thiocol oligomer. The optimum polycondensation temperature was taken …

Synthesis And Structure Of The Coordination Complex Of Copper Ion With Collagen, Dildorа Sadikova, Adham Rafikov, Oybek Tursunqulov, Dilnoza Soyibova

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to synthesize, determine the composition and microstructure of complexes of copper (II) sulfate with collagen for use as a dye for textile material. Coordination complexes of copper (II) sulfate with collagen synthesized at different ratios of the initial substances by the interaction of solutions of different concentrations of copper sulfate and collagen of raw skin. With an increase in the salt content, the yield of the reaction product increases. With an excess of collagen, some of it does not bind into a complex and precipitates. With an excess of salt, almost the weight of …

Synthesis Of Sodium Ammonium Hydrophosphate And Sodium Dihydrophosphate Based On Extraction Phosphoric Acid From Central Kyzylkum Phosphorites, Kamola Arifdjanova, Kholtura Mirzakulov, Sherzod Khujamberdiev, Melikulova Gavkhar

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the research is the synthesis of sodium ammonium hydrogen phosphate and sodium dihydrogen phosphate based on purified extraction phosphoric acid.

The acid was purified from accompanying impurities by precipitation methods using sodium carbonate and metasilicate, washed burnt phosphoconcentrate, barium carbonate, acid neutralization with gaseous ammonia. Pre-neutralization of the purified solution of monoammonium phosphate with sodium carbonate to the ratio Na₂O:P₂O₅ = 0.44 and subsequent drying at a temperature of 50 °С allows to obtain sodium ammonium hydrogen phosphate tetrahydrate, and at 100 °С sodium dihydrogen phosphate monohydrate.

The individuality and purity of …

Physico-Chemical Properties And Structural Transformations In The Synthesis Of Boroalumosilicate Glass-Crystal Materials, Julia Yeganyan

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is to study the areas of glass formation and metastable liquation of the pseudo-ternary system (MgO·Al₂O₃)-B₂O₃-SiO₂, and study of the crystallization process of glasses of cordierite composition. The crystallization process of glasses of cordierite composition containing B₂O₃ by a single-stage heat treatment at 1000 ^oC and 1200 ^oC, the nature of crystallization, the thermal properties of glasses and glass crystalline materials of the system (MgO·A_l2O₃)-B₂O₃-SiO₂ were studied. It revealed that during …

Simulation Of Optical Properties Of Dielectric Layers From Visible To Near Infrared Spectral Range, Andrew Cochran, Cory Conkel

ONU Student Research Colloquium

Optical properties of dielectrics play a critical role in various applications including the design and manufacture of optical components & devices such as detectors, filters, imagers, lenses, optical coatings, photonic crystals, sensors and waveguides, and solar cells. Radiative properties of varying thicknesses of different dielectrics such as Aluminum Oxide (Al2O3), Silicon Dioxide (SiO2), Indium Tin Oxide (ITO), Magnesium Fluoride (MgF2) and Silicon Nitride (Si3N4) have been simulated and compared in the range of visible to near infrared by mathematical modelling using MATLAB simulations. The results of the evolution of the radiative properties, as a function of dielectric material thickness, on …

Polymers And Solvents Used In Membrane Fabrication: A Review Focusing On Sustainable Membrane Development, Xiaobo Dong, David Lu, Tequila A. L. Harris, Isabel C. Escobar

Chemical and Materials Engineering Faculty Publications

(1) Different methods have been applied to fabricate polymeric membranes with non-solvent induced phase separation (NIPS) being one of the mostly widely used. In NIPS, a solvent or solvent blend is required to dissolve a polymer or polymer blend. N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF) and other petroleum-derived solvents are commonly used to dissolve some petroleum-based polymers. However, these components may have negative impacts on the environment and human health. Therefore, using greener and less toxic components is of great interest for increasing membrane fabrication sustainability. The chemical structure of membranes is not affected by the use of different solvents, …

An Alternative Approach To Nucleic Acid Memory, George D. Dickinson, Golam Md Mortuza, William Clay, Luca Piantanida, Christopher M. Green, Chad Watson, Eric J. Hayden, Tim Andersen, Wan Kuang, Elton Graugnard, Reza Zadegan, William L. Hughes

Materials Science and Engineering Faculty Publications and Presentations

DNA is a compelling alternative to non-volatile information storage technologies due to its information density, stability, and energy efficiency. Previous studies have used artificially synthesized DNA to store data and automated next-generation sequencing to read it back. Here, we report digital Nucleic Acid Memory (dNAM) for applications that require a limited amount of data to have high information density, redundancy, and copy number. In dNAM, data is encoded by selecting combinations of single-stranded DNA with (1) or without (0) docking-site domains. When self-assembled with scaffold DNA, staple strands form DNA origami breadboards. Information encoded into the breadboards is read by …