Chemical Engineering Commons^™

A Polarizable Reactive Force Field For Water To Enable Molecular Dynamics Simulations Of Proton Transport, Abhishek Asthana, Dean R. Wheeler

Faculty Publications

A new polarizable water model is developed for molecular dynamics (MD) simulations of the proton transport process. The interatomic potential model has three important submodels corresponding to electrostatic interactions, making and breaking of covalent bonds, and treatment of electron exchange and correlation through a van der Waals potential. A polarizable diffuse charge density function was used to describe Coulombic interactions between atoms. Most of the model parameters were obtained from ab initio data for a lone water molecule. Molecules respond realistically to their electrochemical environment by the use of coupled fluctuating charge and fluctuating dipole dynamics, which controlled the charge …

Aluminium-Free Glass Polyalkenoate Cements: Ion Release And In Vitro Antibacterial Efficacy, A. W. Wren, J. P. Hansen, S. Hayakawa, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements (GPCs) have exhibited potential as bone cements. This study investigates the effect of substituting TiO₂ for SiO₂ in the glass phase and the subsequent effect on cement rheology, mechanical properties, ion release and antibacterial properties. Glass characterization revealed a reduction in glass transition temperature (T_g) from 685 to 669 C with the addition of 6 mol % TiO₂ (AT-2). Magic angle spinning nuclear magnetic resonance (MAS-NMR) revealed a shift from -81 ppm to -76pmm when comparing a Control glass to AT-2, indicating de-polymerization of the Si network. The incorporation of TiO_{2 …}

Hydrothermal Synthesis Of Pure Li4Ti5O12 And Its Electrochemical Performance, Wen-Jun Xie, Yu-Shi He, Hong Wang, Xiao-Zhen Liao, Zi-Feng Ma

Journal of Electrochemistry

Spinel Li₄Ti₅O₁₂ was prepared by hydrothermal method using commercial anatase (TiO₂) and lithium hydroxide (LiOH) as raw materials. The effects of the LiOH concentration of lithium hydroxide, hydrothermal reaction time and calcination temperature on the structure and electrochemical performance of Li₄Ti₅O₁₂ were investigated. The formation process of Li₄Ti₅O₁₂ was also proposed. The micro-structure and morphology wereas characterized by XRD, SEM, TEM techniques, and the electrochemical performance was analyzed by galvanostatic charge-discharge test. The results show that the pure phase spinel Li₄Ti …

Preparation And Catalytic Properties Of Feco Alloy Nanocatalyst, Ming-Xuan Li, Jie-Lian Ou, Sheng-Pei Chen, Peng Wang, Bin-Bin Xu, Shi-Gang Sun

Journal of Electrochemistry

The FeCo alloy nanoparticles were electrodeposited on glassy carbon electrode by chronoamperometry and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the shapes of FeCo nanoparticles were cubes with an average size of 65 nm. The atom ratio of Fe and Co is 1:1. As indicated from the pattern of selected area electron diffraction (SAED), the FeCo cubic nanoparticles were single crystal which belonged to body-centered cubic with an interval of 0.201 nm referring to the (110) facets of FeCo alloy. The FeCo cubic nanoparticles exhibited the enhanced electrocatalytic …

Electrochemical Performance Of Lifepo4/C Synthesized Via Aqueous Solution-Evaporation Route, Ning-Yu Gu, Xing-Hua He, Yang Li

Journal of Electrochemistry

The LiFePO₄/C samples have been synthesized via an aqueous solution-evaporation route with LiH₂PO₄, FeC₂O₄.2H₂O as raw materials and citric acid as a carbon source. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze structure and morphology of the samples. The electrochemical performances of the LiFePO₄/C cathodes were characterized by charge/discharge cures and electrochemical impedance spectroscopy (EIS). The results show that the LiFePO₄/C sample, calcined at 700 °C and contained 3.03% (by mass) carbon, exhibited a highly pure …

Preparation And Methanol Electrooxidation Of Pt/Pmo12/Pedot/Gc Electrodes, Jing-Hua Ma, Rui-Xiang Wang, Yi-Liang Tan, Shan-Shan Wang, Yan-Qin Zhang, You-Jun Fan

Journal of Electrochemistry

Modification of phosphomolybdic acid (PMo₁₂) on poly(3,4-ethylenedioxythiophene) (PEDOT) film (PEDOT/GC) obtained through the electrochemical polymerization was performed using adsorption method (PMo₁₂/PEDOT/GC), followed by electrodepositing Pt on PMo₁₂/PEDOT/GC to prepare Pt/PMo₁₂/PEDOT/GC electrode. Effects of PMo₁₂ and PEDOT on the methanol oxidation performance of electrode were investigated. Results showed that PMo₁₂ obviously changed the morphology and structure of Pt loaded on the electrode, leading to the formation of sharp thorns at the edge of Pt nanostructures. Cyclic voltammetry and chronoamperometry data demonstrated that the catalytic activities of methanol electrooxidation on the Pt/PMo …

Synthesis And Electrochemical Performance Of Si/C Composite Modified By Pani, Guang-Hui Zhang, Pei-Kang Shen, Ge Sang, Ren-Jin Xiong

Journal of Electrochemistry

Silicon/carbon (Si/C) composite materials were prepared through high-energy ball milling and high-temperature solid-phase method, and then coated with thin polyaniline (PAni) film by oxidation. The microstructure and component of the composites were characterized by SEM, XRD, IR, TG, and the electrochemical performance was investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The results showed that the surface of PAni/Si/G/C composite was coating with complete lamellar structure of PAni film. Its reversible capacity was 784 mAh·g^-1 and 690 mAh·g^-1 could be maintained after 50th charge-discharge cycles.

Synthesis Of Lifepo4/C Cathode By Sol-Gel And Calcining Method With Chitosan Monomer, Jia Xu, Yan-Yan Wang, Rui Wang, Bo Wang, Yue Pan, Dian-Xue Cao, Gui-Ling Wang

Journal of Electrochemistry

The LiFePO₄/C cathode materials for Li-ion battery were synthesized by sol-gel and calcining method using chitosan monomer as a carbon source and a gelating agent. The structures and morphologies were characterized by X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM). The electrochemical performance was investigated by the galvanostatic charge–discharge test. When the molar ratios between chitosan monomer and LiFePO₄ were 1:1.2, the LiFePO₄/C cathode calcined at 600 ^oC showed the best performance. The particle sizes ranged 200 ～ 400 nm. The initial discharge capacity of 155 mAh·g-¹ was achieved at room temperature …

Synthesis And Electrocatalysis Of Pdcu Alloy Nanocrystals, Hai-Bin Wu, Rui-Zhong Zhang, Wei Chen

Journal of Electrochemistry

Monodispersed PdCu alloy nanoparticles were synthesized by co-reduction of Cu(acac)2 and Pd(acac)2 with 1, 2-hexadecanediol. The spherical and popcorn-like shapes of PdCu alloy nanoparticles were obtained by changing the ratios of mixed surface protecting ligands of 1-octadecene, and oleylamine or oleic acid. TEM and XRD measurements showed that both PdCu nanoparticles are alloy nanocrystals dominated with (111) planes and the average sizes are 12.7 ± 0.18 and 20.4 ± 0.31 nm for he spherical and popcorn-like PdCu nanoparticles, respectively. The electrocatalytic activities of the PdCu nanocrystals for formic acid oxidation were evaluated by electrochemical cyclic voltammetry (CV). The result showed …

Electrochemical Synthesis Of Hierarchical Dendritic Polyaniline Nanostructures, Shao-Huang Weng, Jian-Zhang Zhou, Zhong-Hua Lin, Xin-Hua Lin

Journal of Electrochemistry

In this work, the p-TSA doped and hierarchical dendritic nanostructured polyanilines (PANI) have been prepared by potentiostatic electropolymerization without using any templates at room temperature. The mechanism of the polymerization has been discussed according to the electrodeposition curves. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to confirm the formation of uniform hierarchical dendritic structure on PANI. UV-Vis spectroscopy (UV-Vis) and infrared spectroscopy (FTIR) proved that the prepared PANI is in the form of emeraldine salt. The templateless electrodeposition method is simple, easy to operate, can be applied to fabricate other nanostructures of conducting polymers.

Applied Analysis Of Ionic Polymer Metal-Composite Actuators, Siul Ruiz, Benjamin Mead, Woosoon Yim

College of Engineering: Graduate Celebration Programs

• IPMC is a type of smart material called an electroactive polymer
• Consists of an ionic polymer such as Nafion or Flemion and a conducive metal such as platinum or gold
• COMSOL multi-physics simulations accurately model the experimental displacement results
• Optimization performed using the multi-physics model to find the maximum deflection, force, and twisting
• Using the closed loop control system accurate IPMC tip location can be achieved
• This control system has been extended to function using a computer mouse as an input

Energy Audit In Wastewater Aeration System, Dinesh R. Kandel, Jacimaria R. Batista, Sajjad Ahmad

College of Engineering: Graduate Celebration Programs

To evaluate the energy consumption air to aeration basins in wastewater treatment aeration system and to compare the standard computations of oxygen demand and blower power requirements with the actual plant data.

Revisiting Blob Theory For Dna Diffusivity In Slitlike Confinement, Liang Dai, Douglas R. Tree, Johan R. C. Van Der Maarel, Kevin D. Dorfman, Patrick S. Doyle

Faculty Publications

Blob theory has been widely applied to describe polymer conformations and dynamics in nanoconfinement. In slit confinement, blob theory predicts a scaling exponent of 2/3 for polymer diffusivity as a function of slit height, yet a large body of experimental studies using DNA produce a scaling exponent significantly less than 2/3. In this work, we develop a theory that predicts that this discrepancy occurs because the segment correlation function for a semiflexible chain such as DNA does not follow the Flory exponent for length scales smaller than the persistence length. We show that these short length scale effects contribute significantly …

Enhancing In Vitro Production Of Exotic Proteins Utilizing Linear Dna Templates, Savannah Herdegen, Dr. Brad Bundy

Journal of Undergraduate Research

[Final report posting is embargoed pending publication.]

New Capabilities In Large-Scale Models In Computational Biology, Casey Abbott, Dr. John Hedengren

Journal of Undergraduate Research

Advances in biomedical research have lead to an increase of experimental data to be interpreted in the context of reaction pathways, molecular transport, and population dynamics. Kinetic modeling is one way employed to interpret this data and is used in the pharmaceutical industry in developing clinical trials for new medications [1]. One collection of kinetic models is built on the System Biology Markup Language (SBML). Many of these models have detailed reaction metabolic pathways that describe biological systems, including cause and effect relationships in the human body. While simulations of these biological systems have been successfully applied for many years, …

An Alternative Method To Prepare Cobalt Catalysts Using Salt Precursors, Trevor Seegmiller, Dr. Calvin Bartholomew

Journal of Undergraduate Research

Fischer-Tropsch synthesis (FTS) is the process for converting syngas (carbon monoxide and hydrogen) into liquid fuels such as gasoline and diesel. A cobalt or iron catalyst is required for the process. Cobalt catalysts have the highest effectiveness and stability in FTS; however, they are more expensive due to higher materials cost as well as the time-consuming and complex processes generally associated with manufacture.

Development Of A Fuel-Efficient Stove To Reduce Particulate Emissions, Geoffrey Lemon, Dr. Randy Lewis

Journal of Undergraduate Research

According to the World Health Organization, one of the leading causes of death in developing countries is respiratory disease, caused by inhalation of particulates from cooking stoves.¹ With this challenge in mind, our team of interdisciplinary engineering students worked for over two semesters on designing and implementing a more effective stove for the people in Matinga, Peru. With the help and feedback of faculty members and other teams within our Global Engineering Outreach class, we chose to design a modified “rocket stove.” This design was chosen to more completely combust the fuel, producing a much cleaner burning fire.

Gold Nanoparticle Conjugation With A2 Protein In Vlp For Symmetrical Alignment, Matthew Burnham, Dr. Brad Bundy

Journal of Undergraduate Research

A Virus-like Particle (VLP) is a nanostructure composed of many coat proteins. They differ from real viruses in that they are synthesized to be non-infectious. VLPs have many useful applications in vaccines, drug delivery, gene therapy, and material science¹. Last year, I attempted to create a high resolution image of the VLP Q-beta. This was to be accomplished by making modifications to the virus’ structure after its creation. Conjugating a gold nanoparticle to the Q-beta VLP-A2 protein complex would, in theory, provide a site of orientation and allow us to image the VLP (Figure 1). Although the goal …

Scaffold Design Of A Novel Nano-Particle For Single-Target Imaging, Chad Varner, Dr. Brad Bundy

Journal of Undergraduate Research

The purpose of this project has been to help develop a novel nano-imaging particle. Current methodologies have limitations that preclude them from being used for nanometric (1-500nm) imaging processes in living organisms. These include, but are not limited to, low signal to noise ratios, limited target specificity, and bio-incompatibility. To further the possibilities available for nano-imaging, we have attempted to create a scaffold, or framework, for a biocompatible nanoparticle that is capable of imaging specific targets in living systems.

Cell-Free Protein Synthesis Extract Preparation Methods, Troy Holland, Dr. Brad Bundy

Journal of Undergraduate Research

My ORCA project proposed to test and optimize various low capital cost cell lysis methods, while leaving the internal cell machinery intact and viable for cell-free protein synthesis research. Our cells of interest were a strain of the bacterium E. coli, and their cellular machinery consists of the chemicals and enzymes they use in their every-day life processes, including (and of particular interest to us) the synthesis of proteins. These proteins have an almost limitless number of potential applications in medicine, food services, and chemical production, so the various methods of protein synthesis are of significant importance, both financially, and …