Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 31 - 60 of 75

Full-Text Articles in Engineering

Ptfe-Based Microreactor System For The Continuous Synthesis Of Full-Visible-Spectrum Emitting Cesium Lead Halide Perovskite Nanocrystals, Chengxi Zhang, Weiling Luan, Yuhang Yin, Fuqian Yang Nov 2017

Ptfe-Based Microreactor System For The Continuous Synthesis Of Full-Visible-Spectrum Emitting Cesium Lead Halide Perovskite Nanocrystals, Chengxi Zhang, Weiling Luan, Yuhang Yin, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Colloidal perovskite nanocrystals comprised of all inorganic cesium lead halide (CsPbX3, X = Cl, Br, I or a mixture thereof) have potential as optical gain materials due to their high luminescence efficiency. In this work, cesium lead halide nanocrystals are continuously synthesized via a microreactor system consisting of poly(tetrafluoroethylene) (PTFE) capillaries. The synthesized nanocrystals possess excellent optical properties, including a full width at half maximum of 19–35 nm, high fluorescence quantum yield of 47.8–90.55%, and photoluminescence emission in the range of 450–700 nm. For the same precursor concentrations, the photoluminescence emission peak generally increases with increasing reaction temperature, …


Effect Of Oxide On Surface Tension Of Molten Metal, Chunkai Li, Yu Shi, Yufen Gu, Fuqian Yang Nov 2017

Effect Of Oxide On Surface Tension Of Molten Metal, Chunkai Li, Yu Shi, Yufen Gu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Oxides as one of the commonly activating fluxes used in active tungsten inert gas welding (A-TIG welding) can dramatically increase the penetration depth to 2–4 times that of conventional welding. Using the oscillation principle of inviscid fluid, a robust method is developed to measure the average surface tension of molten metal during A-TIG welding for four different oxide activating fluxes of B2O3, TiO2, SiO2, and MgO. The experimental results suggest that the oxygen released from the decomposition of oxides is the dominant factor contributing to the change of the surface tension, which …


Development Of Novel N-Isopropylacrylamide (Nipaam) Based Hydrogels With Varying Content Of Chrysin Multiacrylate, Shuo Tang, Martha Floy, Rohit Bhandari, Thomas D. Dziubla, J. Zach Hilt Oct 2017

Development Of Novel N-Isopropylacrylamide (Nipaam) Based Hydrogels With Varying Content Of Chrysin Multiacrylate, Shuo Tang, Martha Floy, Rohit Bhandari, Thomas D. Dziubla, J. Zach Hilt

Chemical and Materials Engineering Faculty Publications

A series of novel temperature responsive hydrogels were synthesized by free radical polymerization with varying content of chrysin multiacrylate (ChryMA). The goal was to study the impact of this novel polyphenolic-based multiacrylate on the properties of N-isopropylacrylamide (NIPAAm) hydrogels. The temperature responsive behavior of the copolymerized gels was characterized by swelling studies, and their lower critical solution temperature (LCST) was characterized through differential scanning calorimetry (DSC). It was shown that the incorporation of ChryMA decreased the swelling ratios of the hydrogels and shifted their LCSTs to a lower temperature. Gels with different ChryMA content showed different levels of response to …


Spontaneous Jumping, Bouncing And Trampolining Of Hydrogel Drops On A Heated Plate, Jonathan T. Pham, Maxime Paven, Sanghyuk Wooh, Tadashi Kajiya, Hans-Jürgen Butt, Doris Vollmer Oct 2017

Spontaneous Jumping, Bouncing And Trampolining Of Hydrogel Drops On A Heated Plate, Jonathan T. Pham, Maxime Paven, Sanghyuk Wooh, Tadashi Kajiya, Hans-Jürgen Butt, Doris Vollmer

Chemical and Materials Engineering Faculty Publications

The contact between liquid drops and hot solid surfaces is of practical importance for industrial processes, such as thermal spraying and spray cooling. The contact and bouncing of solid spheres is also an important event encountered in ball milling, powder processing, and everyday activities, such as ball sports. Using high speed video microscopy, we demonstrate that hydrogel drops, initially at rest on a surface, spontaneously jump upon rapid heating and continue to bounce with increasing amplitudes. Jumping is governed by the surface wettability, surface temperature, hydrogel elasticity, and adhesion. A combination of low-adhesion impact behavior and fast water vapor formation …


Improving The Thermal Stability Of Cellobiohydrolase Cel7a From Hypocrea Jecorina By Directed Evolution, Frits Goedegebuur, Lydia Dankmeyer, Peter Gualfetti, Saeid Karkehabadi, Henrik Hansson, Suvamay Jana, Vicky Huynh, Bradley R. Kelemen, Paulien Kruithof, Edmund A. Larenas, Pauline J. M. Teunissen, Jerry Ståhlberg, Christina M. Payne, Colin Mitchinson, Mats Sandgren Aug 2017

Improving The Thermal Stability Of Cellobiohydrolase Cel7a From Hypocrea Jecorina By Directed Evolution, Frits Goedegebuur, Lydia Dankmeyer, Peter Gualfetti, Saeid Karkehabadi, Henrik Hansson, Suvamay Jana, Vicky Huynh, Bradley R. Kelemen, Paulien Kruithof, Edmund A. Larenas, Pauline J. M. Teunissen, Jerry Ståhlberg, Christina M. Payne, Colin Mitchinson, Mats Sandgren

Chemical and Materials Engineering Faculty Publications

Secreted mixtures of Hypocrea jecorina cellulases are able to efficiently degrade cellulosic biomass to fermentable sugars at large, commercially relevant scales. H. jecorina Cel7A, cellobiohydrolase I, from glycoside hydrolase family 7, is the workhorse enzyme of the process. However, the thermal stability of Cel7A limits its use to processes where temperatures are no higher than 50 °C. Enhanced thermal stability is desirable to enable the use of higher processing temperatures and to improve the economic feasibility of industrial biomass conversion. Here, we enhanced the thermal stability of Cel7A through directed evolution. Sites with increased thermal stability properties were combined, and …


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 …


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: …


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% …


Size And Shape Distributions Of Primary Crystallites In Titania Aggregates, Eric A. Grulke, Kazuhiro Yamamoto, Kazuhiro Kumagai, Ines Häusler, Werner Österle, Erik Ortel, Vasile-Dan Hodoroaba, Scott C. Brown, Christopher Chan, Jiwen Zheng, Kenji Yamamoto, Kouji Yashiki, Nam Woong Song, Young Heon Kim, Aleksandr B Stefaniak, D. Schwegler-Berry, Victoria A. Coleman, Åsa K. Jämting, Jan Herrmann, Toru Arakawa, Woodrow W. Burchett, Joshua W. Lambert, Arnold J. Stromberg Jul 2017

Size And Shape Distributions Of Primary Crystallites In Titania Aggregates, Eric A. Grulke, Kazuhiro Yamamoto, Kazuhiro Kumagai, Ines Häusler, Werner Österle, Erik Ortel, Vasile-Dan Hodoroaba, Scott C. Brown, Christopher Chan, Jiwen Zheng, Kenji Yamamoto, Kouji Yashiki, Nam Woong Song, Young Heon Kim, Aleksandr B Stefaniak, D. Schwegler-Berry, Victoria A. Coleman, Åsa K. Jämting, Jan Herrmann, Toru Arakawa, Woodrow W. Burchett, Joshua W. Lambert, Arnold J. Stromberg

Chemical and Materials Engineering Faculty Publications

The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions …


Desulfination By 2′-Hydroxybiphenyl-2-Sulfinate Desulfinase Proceeds Via Electrophilic Aromatic Substitution By The Cysteine-27 Proton, Inacrist Geronimo, Shawn R. Nigam, Christina M. Payne May 2017

Desulfination By 2′-Hydroxybiphenyl-2-Sulfinate Desulfinase Proceeds Via Electrophilic Aromatic Substitution By The Cysteine-27 Proton, Inacrist Geronimo, Shawn R. Nigam, Christina M. Payne

Chemical and Materials Engineering Faculty Publications

Biodesulfurization is an attractive option for enzymatically removing sulfur from the recalcitrant thiophenic derivatives that comprise the majority of organosulfur compounds remaining in hydrotreated petroleum products. Desulfurization in the bacteria Rhodococcus erythropolis follows a four-step pathway culminating in C–S bond cleavage in the 2′-hydroxybiphenyl-2-sulfinate (HBPS) intermediate to yield 2-hydroxybiphenyl and bisulfite. The reaction, catalyzed by 2′-hydroxybiphenyl-2-sulfinate desulfinase (DszB), is the rate-limiting step and also the least understood, as experimental evidence points to a mechanism unlike that of other desulfinases. On the basis of structural and biochemical evidence, two possible mechanisms have been proposed: nucleophilic addition and electrophilic aromatic substitution. Density …


Pore Functionalized Pvdf Membranes With In-Situ Synthesized Metal Nanoparticles: Material Characterization, And Toxic Organic Degradation, Hongyi Wan, Nicolas J. Briot, Anthony Saad, Lindell E. Ormsbee, Dibakar Bhattacharyya May 2017

Pore Functionalized Pvdf Membranes With In-Situ Synthesized Metal Nanoparticles: Material Characterization, And Toxic Organic Degradation, Hongyi Wan, Nicolas J. Briot, Anthony Saad, Lindell E. Ormsbee, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

Functionalized PVDF membrane platforms were developed for environmentally benign in-situ nanostructured Fe/Pd synthesis and remediation of chlorinated organic compounds. To prevent leaching and aggregation, nanoparticle catalysts were integrated into membrane domains functionalized with poly (acrylic acid). Nanoparticles of 16–19 nm were observed inside the membrane pores by using focused ion beam (FIB). This technique prevents mechanical deformation of the membrane, compared to the normal SEM preparation methods, thus providing a clean, smooth surface for nanoparticles characterization. This allowed quantification of nanoparticle properties (size and distribution) versus depth underneath the membrane surface (0–20 μm). The results showed that nanoparticles were uniformly …


Synthesis Of Graphene Oxide Membranes And Their Behavior In Water And Isopropanol, Ashish Aher, Yuguang Cai, Mainak Majumder, Dibakar Bhattacharyya May 2017

Synthesis Of Graphene Oxide Membranes And Their Behavior In Water And Isopropanol, Ashish Aher, Yuguang Cai, Mainak Majumder, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

Graphene oxide (GO) membrane has been synthesized on commercial polysulfone ultrafiltration membranes (Pore size: 17 nm) using the drop casting method followed by baking at 90 C for 24 h. Baking resulted in the reduction of GO and removal of bulk water intercalated in the GO sheets. Deposited GO film showed high stability under shear stress variation. This work shows that water adsorption on the GO membrane determines its permeation performance. Despite the higher viscosity of isopropyl alcohol (IPA), its permeability was 7 times higher than water through the baked (“dry”) GO membranes, which were never contacted with water. However, …


Chemically Stable Artificial Sei For Li-Ion Battery Electrodes, Qinglin Zhang, Lei Han, Jie Pan, Zhi Chen, Yang-Tse Cheng Mar 2017

Chemically Stable Artificial Sei For Li-Ion Battery Electrodes, Qinglin Zhang, Lei Han, Jie Pan, Zhi Chen, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

The importance of coating's chemical stability in lithium-ion batteries has been demonstrated by this study. It is well known that the mechanical properties determine the cycle life, and chemical stability or chemical degradation rate determines the calendar life. In this study, we used HfO2 coatings prepared by atomic layer deposition as an example to show the chemical stability of the coatings for lithium ion battery electrodes.


Synthesis And Catalytic Applications Of Non-Metal Doped Mesoporous Titania, Syed Z. Islam, Suraj R. Nagpure, Doo Young Kim, Stephen E. Rankin Mar 2017

Synthesis And Catalytic Applications Of Non-Metal Doped Mesoporous Titania, Syed Z. Islam, Suraj R. Nagpure, Doo Young Kim, Stephen E. Rankin

Chemical and Materials Engineering Faculty Publications

Mesoporous titania (mp-TiO2) has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO2. However, because the large band gap of TiO2 limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO2. While first-principles calculations support the efficacy of this approach, it is challenging to …


Incorporating Poly(3-Hexyl Thiophene) Into Orthogonally Aligned Cylindrical Nanopores Of Titania For Optoelectronics, Suraj R. Nagpure, James F. Browning, Stephen E. Rankin Mar 2017

Incorporating Poly(3-Hexyl Thiophene) Into Orthogonally Aligned Cylindrical Nanopores Of Titania For Optoelectronics, Suraj R. Nagpure, James F. Browning, Stephen E. Rankin

Chemical and Materials Engineering Faculty Publications

The incorporation of hole conducting polymer poly(3-hexyl thiophene) (P3HT) into the 8-9 nm cylindrical nanopores of titania is investigated using films with a unique orthogonally oriented hexagonal close packed mesostructure. The films are synthesized using evaporation induced self-assembly (EISA) with Pluronic triblock copolymer F127 as the structure directing agent. The orthogonally oriented cylindrical nanopore structure was chosen over a cubic structure because confinement in uniform cylindrical channels is hypothesized to enhance hole conductivity of P3HT by inducing local polymer chain ordering. Orthogonal orientation of the cylindrical nanopores is achieved by modifying the substrate (FTO-coated glass slides) with crosslinked F127. After …


Toxicity Evaluation Of Magnetic Hyperthermia Induced By Remote Actuation Of Magnetic Nanoparticles In 3d Micrometastasic Tumor Tissue Analogs For Triple Negative Breast Cancer, Nathanael A. Stocke, Pallavi Sethi, Amar Jyoti, Ryan Chan, Susanne M. Arnold, J. Zach Hilt, Meenakshi Upreti Mar 2017

Toxicity Evaluation Of Magnetic Hyperthermia Induced By Remote Actuation Of Magnetic Nanoparticles In 3d Micrometastasic Tumor Tissue Analogs For Triple Negative Breast Cancer, Nathanael A. Stocke, Pallavi Sethi, Amar Jyoti, Ryan Chan, Susanne M. Arnold, J. Zach Hilt, Meenakshi Upreti

Chemical and Materials Engineering Faculty Publications

Magnetic hyperthermia as a treatment modality is acquiring increased recognition for loco-regional therapy of primary and metastatic lung malignancies by pulmonary delivery of magnetic nanoparticles (MNP). The unique characteristic of magnetic nanoparticles to induce localized hyperthermia in the presence of an alternating magnetic field (AMF) allows for preferential killing of cells at the tumor site. In this study we demonstrate the effect of hyperthermia induced by low and high dose of MNP under the influence of an AMF using 3D tumor tissue analogs (TTA) representing the micrometastatic, perfusion independent stage of triple negative breast cancer (TNBC) that infiltrates the lungs. …


Field-Induced Formation And Growth Of Pillars On Films Of Bisphenol-A-Polycarbonate, Yu-Fan Chuang, Jyun-Siang Peng, Fuqian Yang, Donyau Chiang, Sanboh Lee Jan 2017

Field-Induced Formation And Growth Of Pillars On Films Of Bisphenol-A-Polycarbonate, Yu-Fan Chuang, Jyun-Siang Peng, Fuqian Yang, Donyau Chiang, Sanboh Lee

Chemical and Materials Engineering Faculty Publications

An electric field is used to construct pillars on films of bisphenol-A-polycarbonate (BPAPC) between two parallel electrodes. Both the size and density of the pillars are dependent on the film thickness. For the same experimental conditions, thicker films will lead to the formation of pillars of larger sizes and smaller densities. The time dependence of the average diameter of the pillars is found to be a linear function of the square root of the difference between the annealing time and incubation time. The temperature dependence of the temporal evolution of the pillars follows the Arrhenius relation with an activation enthalpy …


Fatigue Properties And Damage Mechanism Of A Cr-Mn Austenite Steel, Z. Q. Lv, Pei Cai, T. Yu, Yan Jin, H. F. Zhang, Tongguang Zhai, W. T. Fu Jan 2017

Fatigue Properties And Damage Mechanism Of A Cr-Mn Austenite Steel, Z. Q. Lv, Pei Cai, T. Yu, Yan Jin, H. F. Zhang, Tongguang Zhai, W. T. Fu

Chemical and Materials Engineering Faculty Publications

The fatigue properties and the damage mechanism of a Cr-Mn austenite steel were investigated using four-point bend fatigue testing. The stress-number of cycles to failure (S-N) curve of the Cr-Mn austenite steel was measured at room temperature, at the frequency of f=20 Hz and the stress ratio of R=0.1. The fatigue strength of this Cr-Mn austenite steel was measured to be 503 MPa in the maximum stress. Multiple cracks are initiated on the sample surface after fatigue failure tests, and usually only one or two of them can lead to the final failure of the samples. Most of the cracks …


Interplay Of Composition, Structure, And Electron Density Of States In W-Os Cathode Materials And Relationship With Thermionic Emission, Qunfei Zhou, Thomas John Balk, Matthew J. Beck Jan 2017

Interplay Of Composition, Structure, And Electron Density Of States In W-Os Cathode Materials And Relationship With Thermionic Emission, Qunfei Zhou, Thomas John Balk, Matthew J. Beck

Chemical and Materials Engineering Faculty Publications

The presence and composition of W-Os alloys have been found to significantly affect the thermionic emission properties of Os-coated tungsten dispenser cathodes. However, the comprehensive understanding of structure–property relationships needed to design improved tungsten cathodes with larger thermionic emission is still lacking. In this study, composition–structure–property relationships governing thermionic emission from W-Os alloys were investigated using quantum mechanical calculations. Low-energy W-Os atomic configurations at various compositions were determined from first-principles calculations based on density functional theory in combination with cluster expansion calculations. Electronic properties were investigated in terms of the electron density of states. The relative position of the Fermi …


Inhibition Of Mammalian Glycoprotein Ykl-40 Identification Of The Physiological Ligand, Abhishek A. Kognole, Christina M. Payne Jan 2017

Inhibition Of Mammalian Glycoprotein Ykl-40 Identification Of The Physiological Ligand, Abhishek A. Kognole, Christina M. Payne

Chemical and Materials Engineering Faculty Publications

YKL-40 is a mammalian glycoprotein associated with progression, severity, and prognosis of chronic inflammatory diseases and a multitude of cancers. Despite this well documented association, identification of the lectin′s physiological ligand and, accordingly, biological function has proven experimentally difficult. YKL-40 has been shown to bind chito-oligosaccharides; however, the production of chitin by the human body has not yet been documented. Possible alternative ligands include proteoglycans, polysaccharides, and fibers like collagen, all of which makeup the extracellular matrix. It is likely that YKL-40 is interacting with these alternative polysaccharides or proteins within the body, extending its function to cell biological roles …


Preparation And Microstructure Of Machinable Al2O3/Mica Composite By Ball Milling And Hot-Press Sintering, Qingbo Tian, Deyu Kong, Tongguang Zhai Sep 2016

Preparation And Microstructure Of Machinable Al2O3/Mica Composite By Ball Milling And Hot-Press Sintering, Qingbo Tian, Deyu Kong, Tongguang Zhai

Chemical and Materials Engineering Faculty Publications

A machinable α-Al2O3/mica composite was prepared by hot-press sintering. In this experiment, a mica-contained glass ceramic in the MgO-Al2O3-SiO2-F glassy system was employed and the base glass powders were obtained by traditional melting-quenched method. Then, α-Al2O3 milling swarf was introduced by medium α-alumina milling ball to the glass powders. The test results indicate that the composites consist of mica crystal and mullite crystal, which are precipitated in the base glass. The α-Al2O3 shows an irregular polygon, which is inlayed in the base material. With …


Fast Diffusion Of Silver In Tio2 Nanotube Arrays, Wanggang Zhang, Yiming Liu, Diaoyu Zhou, Hui Wang, Wei Liang, Fuqian Yang Aug 2016

Fast Diffusion Of Silver In Tio2 Nanotube Arrays, Wanggang Zhang, Yiming Liu, Diaoyu Zhou, Hui Wang, Wei Liang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Using magnetron sputtering and heat treatment, Ag@TiO2 nanotubes are prepared. The effects of heat-treatment temperature and heating time on the evolution of Ag nanofilms on the surface of TiO2 nanotubes and microstructure of Ag nanofilms are investigated by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. Ag atoms migrate mainly on the outmost surface of the TiO2 nanotubes, and fast diffusion of Ag atoms is observed. The diffusivity for the diffusion of Ag atoms on the outmost surface of the TiO2 nanotubes at 400 °C is 6.87 × 10−18 m2/s, …


Self-Similar Random Process And Chaotic Behavior In Serrated Flow Of High Entropy Alloys, Shuying Chen, Liping Yu, Jingli Ren, Xie Xie, Xueping Li, Ying Xu, Guangfeng Zhao, Peizhen Li, Fuqian Yang, Yang Ren, Peter K. Liaw Jul 2016

Self-Similar Random Process And Chaotic Behavior In Serrated Flow Of High Entropy Alloys, Shuying Chen, Liping Yu, Jingli Ren, Xie Xie, Xueping Li, Ying Xu, Guangfeng Zhao, Peizhen Li, Fuqian Yang, Yang Ren, Peter K. Liaw

Chemical and Materials Engineering Faculty Publications

The statistical and dynamic analyses of the serrated-flow behavior in the nanoindentation of a high-entropy alloy, Al0.5CoCrCuFeNi, at various holding times and temperatures, are performed to reveal the hidden order associated with the seemingly-irregular intermittent flow. Two distinct types of dynamics are identified in the high-entropy alloy, which are based on the chaotic time-series, approximate entropy, fractal dimension, and Hurst exponent. The dynamic plastic behavior at both room temperature and 200 °C exhibits a positive Lyapunov exponent, suggesting that the underlying dynamics is chaotic. The fractal dimension of the indentation depth increases with the increase of temperature, and …


Microstructural Properties And Four-Point Bend Fatigue Behavior Of Ti-6.5al-2zr-1mo-1v Welded Joints By Electron Beam Welding, Peng Liu, Tongguang Zhai, Yuanbin Zhang Jun 2016

Microstructural Properties And Four-Point Bend Fatigue Behavior Of Ti-6.5al-2zr-1mo-1v Welded Joints By Electron Beam Welding, Peng Liu, Tongguang Zhai, Yuanbin Zhang

Chemical and Materials Engineering Faculty Publications

With the help of a four-point-bend of fatigue rig, high-cycle fatigue tests were carried out on an Ti–6.5Al–2Zr-1Mo-1V titanium alloy at room temperature, 20 Hz and R = 0.1 in ambient air. The test results indicated that the fatigue strength of base metal, 888 MPa, is about 120% of yield strength. The fatigue strength of joints is 814 MPa. It is about 110% of yield strength of base metal. When the loading stress is higher, the fatigue failure region is located in middle weld zone of weld face, which the cracks are propagated along coarse β phase’s grain boundary. When …


Large-Area Graphene-Based Nanofiltration Membranes By Shear Alignment Of Discotic Nematic Liquid Crystals Of Graphene Oxide, Abozar Akbari, Phillip Sheath, Samuel T. Martin, Dhanraj B. Shinde, Mahdokht Shaibani, Parama Chakraborty Banerjee, Rachel Tkacz, Dibakar Bhattacharyya, Mainak Majumder Mar 2016

Large-Area Graphene-Based Nanofiltration Membranes By Shear Alignment Of Discotic Nematic Liquid Crystals Of Graphene Oxide, Abozar Akbari, Phillip Sheath, Samuel T. Martin, Dhanraj B. Shinde, Mahdokht Shaibani, Parama Chakraborty Banerjee, Rachel Tkacz, Dibakar Bhattacharyya, Mainak Majumder

Chemical and Materials Engineering Faculty Publications

Graphene-based membranes demonstrating ultrafast water transport, precise molecular sieving of gas and solvated molecules shows great promise as novel separation platforms; however, scale-up of these membranes to large-areas remains an unresolved problem. Here we demonstrate that the discotic nematic phase of graphene oxide (GO) can be shear aligned to form highly ordered, continuous, thin films of multi-layered GO on a support membrane by an industrially adaptable method to produce large-area membranes (13 × 14 cm2) in < 5 s. Pressure driven transport data demonstrate high retention (> 90%) for charged and uncharged organic probe molecules with a hydrated radius above 5 Å as well as modest (30–40%) retention of …


Biopolymeric Mucin And Synthetic Polymer Analogs: Their Structure, Function And Role In Biomedical Applications, Sundar Prasanth Authimoolam, Thomas D. Dziubla Mar 2016

Biopolymeric Mucin And Synthetic Polymer Analogs: Their Structure, Function And Role In Biomedical Applications, Sundar Prasanth Authimoolam, Thomas D. Dziubla

Chemical and Materials Engineering Faculty Publications

Mucin networks are viscoelastic fibrillar aggregates formed through the complex self-association of biopolymeric glycoprotein chains. The networks form a lubricious, hydrated protective shield along epithelial regions within the human body. The critical role played by mucin networks in impacting the transport properties of biofunctional molecules (e.g., biogenic molecules, probes, nanoparticles), and its effect on bioavailability are well described in the literature. An alternate perspective is provided in this paper, presenting mucin’s complex network structure, and its interdependent functional characteristics in human physiology. We highlight the recent advances that were achieved through the use of mucin in diverse areas of bioengineering …


Graphene Oxide Quantum Dots Covalently Functionalized Pvdf Membrane With Significantly-Enhanced Bactericidal And Antibiofouling Performances, Zhiping Zeng, Dingshan Yu, Ziming He, Jing Liu, Fang-Xing Xiao, Yan Zhang, Rong Wang, Dibakar Bhattacharyya, Timothy Thatt Yang Tan Feb 2016

Graphene Oxide Quantum Dots Covalently Functionalized Pvdf Membrane With Significantly-Enhanced Bactericidal And Antibiofouling Performances, Zhiping Zeng, Dingshan Yu, Ziming He, Jing Liu, Fang-Xing Xiao, Yan Zhang, Rong Wang, Dibakar Bhattacharyya, Timothy Thatt Yang Tan

Chemical and Materials Engineering Faculty Publications

Covalent bonding of graphene oxide quantum dots (GOQDs) onto amino modified polyvinylidene fluoride (PVDF) membrane has generated a new type of nano-carbon functionalized membrane with significantly enhanced antibacterial and antibiofouling properties. A continuous filtration test using E. coli containing feedwater shows that the relative flux drop over GOQDs modified PVDF is 23%, which is significantly lower than those over pristine PVDF (86%) and GO-sheet modified PVDF (62%) after 10 h of filtration. The presence of GOQD coating layer effectively inactivates E. coli and S. aureus cells, and prevents the biofilm formation on the membrane surface, producing excellent antimicrobial activity and …


Development Of Pvdf Membrane Nanocomposites Via Various Functionalization Approaches For Environmental Applications, Douglas M. Davenport, Minghui Gui, Lindell E. Ormsbee, Dibakar Bhattacharyya Jan 2016

Development Of Pvdf Membrane Nanocomposites Via Various Functionalization Approaches For Environmental Applications, Douglas M. Davenport, Minghui Gui, Lindell E. Ormsbee, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

Membranes are finding wide applications in various fields spanning biological, water, and energy areas. Synthesis of membranes to provide tunable flux, metal sorption, and catalysis has been done through pore functionalization of microfiltration (MF) type membranes with responsive behavior. This methodology provides an opportunity to improve synthetic membrane performance via polymer fabrication and surface modification. By optimizing the polymer coagulation conditions in phase inversion fabrication, spongy polyvinylidene fluoride (PVDF) membranes with high porosity and large internal pore volume were created in lab and full scale. This robust membrane shows a promising mechanical strength as well as high capacity for loading …


High Capacity Silicon Electrodes With Nafion As Binders For Lithium-Ion Batteries, Jiagang Xu, Qinglin Zhang, Yang-Tse Cheng Dec 2015

High Capacity Silicon Electrodes With Nafion As Binders For Lithium-Ion Batteries, Jiagang Xu, Qinglin Zhang, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Silicon is capable of delivering a high theoretical specific capacity of 3579 mAh g−1 which is about 10 times higher than that of the state-of-the-art graphite based negative electrodes for lithium-ion batteries. However, the poor cycle life of silicon electrodes, caused by the large volumetric strain during cycling, limits the commercialization of silicon electrodes. As one of the essential components, the polymeric binder is critical to the performance and durability of lithium-ion batteries as it keeps the integrity of electrodes, maintains conductive path and must be stable in the electrolyte. In this work, we demonstrate that electrodes consisting of …


Structural And Functional Characterization Of A Lytic Polysaccharide Monooxygenase With Broad Substrate Specificity, Anna S. Borisova, Trine Isaksen, Maria Dimarogona, Abhishek A. Kognole, Geir Mathiesen, Anikó Várnai, Åsmund K. Røhr, Christina M. Payne, Morten Sørlie, Mats Sandgren, Vincent G. H. Eijsink Sep 2015

Structural And Functional Characterization Of A Lytic Polysaccharide Monooxygenase With Broad Substrate Specificity, Anna S. Borisova, Trine Isaksen, Maria Dimarogona, Abhishek A. Kognole, Geir Mathiesen, Anikó Várnai, Åsmund K. Røhr, Christina M. Payne, Morten Sørlie, Mats Sandgren, Vincent G. H. Eijsink

Chemical and Materials Engineering Faculty Publications

The recently discovered lytic polysaccharide monooxygenases (LPMOs) carry out oxidative cleavage of polysaccharides and are of major importance for efficient processing of biomass. NcLPMO9C from Neurospora crassa acts both on cellulose and on non-cellulose β-glucans, including cellodextrins and xyloglucan. The crystal structure of the catalytic domain of NcLPMO9C revealed an extended, highly polar substrate-binding surface well suited to interact with a variety of sugar substrates. The ability of NcLPMO9C to act on soluble substrates was exploited to study enzyme-substrate interactions. EPR studies demonstrated that the Cu2+ center environment is altered upon substrate binding, whereas isothermal titration …