Use Of Bioadvantaged Materials For Use In Bituminous Modification, 2018 Iowa State University
Use Of Bioadvantaged Materials For Use In Bituminous Modification, Conglin Chen, Joseph H. Podolsky, Nacú B. Hernández, Austin Hohmann, R. Christopher Williams, Eric W. Cochran
Eric W. Cochran
Historically, the use of “green” materials around the world has been limited due to their higher production costs when compared to petrochemical derived materials. However, due to the recent volatility and increasing price of petroleum derivatives, there is a growing demand for the use of environmentally friendly materials. One of the most commonly used materials for bitumen modification are poly(styrene-block-butadiene-block-styrene) (SBS) type polymers. Recently, Iowa State University Chemical Engineering Department was able to synthetize thermoplastic elastomers using acrylated epoxidized soybean oil (AESO), a bioadvantaged replacement of butadiene, and styrene with the use of controlled radical polymerization techniques. Initial rheological ...
Synthesis And Functionalization Of Virus-Mimicking Cationic Block Copolymers With Pathogen-Associated Carbohydrates As Potential Vaccine Adjuvants, J. R. Adams, M. Goswami, N. L.B. Pohl, Surya K. Mallapragada
Surya K. Mallapragada
We report the synthesis of a family of amphiphilic pentablock polymers with different cationic blocks and with controlled architectures as potential vaccine carriers for subunit vaccines. The temperature and pH-dependent micellization and gelation of these pentablock copolymers can provide a depot for sustained protein and gene delivery. The amphiphilic central triblock promotes cellular endocytosis, good gene delivery and has been used effectively as a vaccine adjuvant. The pentablock copolymer outer blocks condense DNA spontaneously as a result of electrostatic interactions for sustained combinational therapy. This family of polymers with different cationic groups was evaluated based on DNA complexation-ability and cytotoxicity ...
Abnormal Phase Transition Between Two-Dimensional High-Density Liquid Crystal And Low-Density Crystalline Solid Phases, 2018 University of Chinese Academy of Sciences
Abnormal Phase Transition Between Two-Dimensional High-Density Liquid Crystal And Low-Density Crystalline Solid Phases, Wenbin Li, Longjuan Kong, Baojie Feng, Huixia Fu, Hui Li, Xiao Cheng Zeng, Kehui Wu, Lan Chen
Xiao Cheng Zeng Publications
Some two-dimensional liquid systems are theoretically predicted to have an anomalous phase transition due to unique intermolecular interactions, for example the first-order transition between two-dimensional high-density water and low-density amorphous ice. However, it has never been experimentally observed, to the best of our knowledge. Here we report an entropy-driven phase transition between a high-density liquid crystal and low-density crystalline solid, directly observed by scanning tunneling microscope in carbon monoxide adsorbed on Cu(111). Combined with first principle calculations, we find that repulsive dipole–dipole interactions between carbon monoxide molecules lead to unconventional thermodynamics. This finding of unconventional thermodynamics in two-dimensional ...
Modification Of Wheat Gluten For Improvement Of Binding Capacity With Keratin In Hair, 2018 Jiangnan University
Modification Of Wheat Gluten For Improvement Of Binding Capacity With Keratin In Hair, Shukun Wang, Danyang Meng, Sisi Wang, Zhong Zhang, Ruijin Yang, Wei Zhao
Faculty Publications in Food Science and Technology
In this study, enzymatic hydrolysis and cationization with epoxypropyldodecyldimethylammonium chloride of wheat protein, an economic protein complex containing great amount of disulfide bonds, were conducted to improve properties such as solubility and disassociation behaviour for recovery of damaged hair when used in shampoo. The optimal conditions for enzymatic hydrolysis were pH 8.2, 55°C with Alcalase for 60min. After the selected hydrolysis, the degree of hydrolysis, nitrogen solubility index, foaming capacity index, foam stability index, emulsifying activity index and emulsion stability index of hydrolysate with 58.71% of shortchain peptides (less than 1000 Da) were 8.81%, 39.07 ...
Adsorbed Gas Behaviour And Guest-Host Interactions In Ultramicroporous Metal-Organic Frameworks, 2017 The University of Western Ontario
Adsorbed Gas Behaviour And Guest-Host Interactions In Ultramicroporous Metal-Organic Frameworks, Bligh Desveaux
Electronic Thesis and Dissertation Repository
Metal-organic frameworks (MOFs) are a class of porous materials that have attracted much attention due to their large surface areas, high tunability and their high selectivity for gas adsorption applications. In this work, solid-state nuclear magnetic resonance (SSNMR) experiments and single crystal X-ray diffraction (SCXRD) experiments are used to investigate carbon dioxide adsorption within the ultramicroporous MOFs SIFSIX-3-Zn (Chapter 2) and ZnAtzOx. (Chapter 3). Analysis finds that the CO2 SIFSIX-3-Zn undergoes wobbling motions with a low temperature dependence, and in ZnAtzOx undergoes wobbling and hopping motions with a low temperature dependence. SCXRD is used to precisely determine the CO ...
Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., 2017 University of Louisville
Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., Alexander Aleksandrovich Larin
Electronic Theses and Dissertations
Gas analysis is an important part of our world and gas sensing technology is becoming more essential for various aspects of our life. A novel approach for gas mixture analysis by using portable gas chromatography in combination with an array of highly integrated and selective metal oxide (MOX) sensors has been studied. We developed a system with small size (7 x 13 x 16 inches), low power consumption (~10 W) and absence of special carrier gases designed for portable field analysis (assuming apriori calibration). Low ppb and even sub-ppb level of detection for some VOCs was achieved during the analysis ...
Gamma-Radiation Induced Corrosion Of Alloy 800, 2017 The University of Western Ontario
Gamma-Radiation Induced Corrosion Of Alloy 800, Mojtaba Momeni
Electronic Thesis and Dissertation Repository
This thesis presents a newly developed mechanism and predictive model for the corrosion of Alloy 800. The Fe-Cr-Ni Alloy (Incoloy 800) is mainly used for steam generator (SG) tubing in CANDU and PWR reactors and is a candidate material for the proposed Canadian Supercritical Water Reactor (SCWR) in which it will be exposed to extreme conditions of high radiation flux and large temperature gradients. The influence of gamma radiation and water chemistry conditions on the corrosion behaviour of Alloy 800 are studied in this work. Ionizing radiation creates reducing (•eaq–, •H, •O2-) and oxidizing radiolysis (•OH, H2 ...
Superconductivity At Т≈200 K In Bismuth Cuprates Synthesized Using Solar Energy, 2017 Tbilisi State University
Superconductivity At Т≈200 K In Bismuth Cuprates Synthesized Using Solar Energy, J. Chigvinadze, Juana Acrivos, S. Ashimov, D. Gulamova, G. Donadze
Faculty Publications, Chemistry
When investigating low-frequency (0.1 Hz) oscillations of multiphase high-temperature cuprate superconductors (HTCS) Bi1,7Pb0,3Sr2Ca(n-1)CunOy (n=2-30), a wide attenuation peak (ΔT~100 К) with a maximum at Т≈200 К was detected. This peak was particularly pronounced in field cooling (FC) experiments, i.e. after abrupt cooling of the sample in the external magnetic field at the temperature Т<Тс with subsequent slow warming up to room temperature with invariance of the applied field. The attenuation peak height depended on the preliminaryorientation (before cooling) of the samples θ in the measured permanent magnetic field Н. On the one hand, it is well known that, after the FC procedure and subsequent slow warming up, at the temperatures close to the critical temperature Тс, the attenuation peak associated with “melting” of the Abrikosov frozen vortex structure and its disappearance at Т >Тс is detected in monophase samples. At the same time, in most multiphase bismuth HTCS samples, synthesized using solar energy and superfast quenching of the melt, the attenuation peak with the maximum at Т≈200 К was ...тс>
Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, 2017 University of Kentucky
Differentiating The Impact Of Nitrogen Chemical States On Optical Properties Of Nitrogen-Doped Graphene Quantum Dots, Timothy Pillar-Little, Doo Young Kim
Chemistry Faculty Publications
The optical properties of top-down synthesized oxidized graphene quantum dots (ox-GQDs) and nitrogen-incorporating graphene quantum dots (N-GQDs) along a range of hydrothermal treatment temperatures were observed. By controlling the hydrothermal treatment temperature, different chemical states of nitrogen atoms were incorporated into GQDs. Below 150 °C, edge-terminating amines and amides dominated the nitrogen content of N-GQDs. Above 150 °C, nitrogen was primarily present in the forms of pyridinic, pyrrolic and quaternary N. In addition to the absorbance and emission profiles of ox-GQDs and N-GQDs, pH-dependent emission spectra were collected to probe chemical states of nitrogen atoms and investigate the relationship between ...
Nucleation And Growth Kinetics For Intercalated Islands During Deposition On Layered Materials With Isolated Point-Like Surface Defects, 2017 Iowa State University and Ames Laboratory
Nucleation And Growth Kinetics For Intercalated Islands During Deposition On Layered Materials With Isolated Point-Like Surface Defects, Yong Han, Ann Lii-Rosales, Y. Zhou, C.-J. Wang, M. Kim, Michael C. Tringides, Cai-Zhuang Wang, Patricia A. Thiel, James W. Evans
Ames Laboratory Accepted Manuscripts
Theory and stochastic lattice-gas modeling is developed for the formation of intercalated metal islands in the gallery between the top layer and the underlying layer at the surface of layered materials. Our model for this process involves deposition of atoms, some fraction of which then enter the gallery through well-separated point-like defects in the top layer. Subsequently, these atoms diffuse within the subsurface gallery leading to nucleation and growth of intercalated islands nearby the defect point source. For the case of a single point defect, continuum diffusion equation analysis provides insight into the nucleation kinetics. However, complementary tailored lattice-gas modeling ...
Comparison Of S-Adsorption On (111) And (100) Facets Of Cu Nanoclusters, 2017 Iowa State University
Comparison Of S-Adsorption On (111) And (100) Facets Of Cu Nanoclusters, Jeffrey S. Boschen, Jiyoung Lee, Theresa L. Windus, James W. Evans, Patricia A. Thiel, Da-Jiang Liu
In order to gain insight into the nature of chemical bonding of sulfur atoms on coinage metal surfaces, we compare the adsorption energy and structural parameters for sulfur at four-fold hollow (4fh) sites on (100) facets and at three-fold hollow (3fh) sites on (111) facets of Cu nanoclusters. Consistent results are obtained from localized atomic orbital and plane-wave based density functional theory using the same functionals. PBE and its hybrid counterpart (PBE0 or HSE06) also give similar results. 4fh sites are preferred over 3fh sites with stronger bonding by ∼0.6 eV for nanocluster sizes above ∼280 atoms. However, for ...
Manipulation Of Dirac Cones In Intercalated Epitaxial Graphene, 2017 Iowa State University and Ames Laboratory
Manipulation Of Dirac Cones In Intercalated Epitaxial Graphene, Minsung Kim, Michael C. Tringides, Matthew T. Hershberger, Shen Chen, Myron Hupalo, Patricia A. Thiel, Cai-Zhuang Wang, Kai-Ming Ho
Ames Laboratory Accepted Manuscripts
Graphene is an intriguing material in view of its unique Dirac quasi-particles, and the manipulation of its electronic structure is important in material design and applications. Here, we theoretically investigate the electronic band structure of epitaxial graphene on SiC with intercalation of rare earth metal ions (e.g., Yb and Dy) using first-principles calculations. The intercalation can be used to control the coupling of the constituent components (buffer layer, graphene, and substrate), resulting in strong modification of the graphene band structure. It is demonstrated that the metal-intercalated epitaxial graphene has tunable band structures by controlling the energies of Dirac cones ...
Nano/Submicro-Structured Iron Cobalt Oxides Based Materials For Energy Storage Application, 2017 Western Kentucky University
Nano/Submicro-Structured Iron Cobalt Oxides Based Materials For Energy Storage Application, Hongyan Gao
Masters Theses & Specialist Projects
Supercapacitors, as promising energy storage devices, have been of interest for their long lifespan compared to secondary batteries, high capacitance and excellent reliability compared to conventional dielectric capacitors. Transition metal oxides can be applied as the electrode materials for pseudocapacitors and offer a much higher specific capacitance. Co3O4 is one of the most investigated transition metal oxides for supercapacitor. Besides simple monometallic oxides, bimetallic transition oxides have recently drawn growing attention in electrochemical energy storage. They present many unique properties such as achievable oxidation states, high electrical conductivities because of the coexistence of two different cations in a single crystal ...
Distinct Ice Patterns On Solid Surfaces With Various Wettabilities, 2017 Chinese Academy of Sciences
Distinct Ice Patterns On Solid Surfaces With Various Wettabilities, Jie Liu, Chongqin Zhu, Kai Liu, Ying Jiang, Yanlin Song, Joseph S. Francisco, Xiao Cheng Zeng, Jianjun Wang
Xiao Cheng Zeng Publications
No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions and the discovery of two growth modes of ice crystals: along-surface and off-surface growth modes. Using atomistic molecular dynamics simulation analysis, we show that these distinct ice growth phenomena are attributable to the presence (or absence) of bilayer ice on solid surfaces with different wettability; that is, the formation of ...
Fabrication And Characterization Of Cuins₂ And Cuinse₂ Light-Absorbing Thin Films For Use In Solar Cells, 2017 The University of Western Ontario
Fabrication And Characterization Of Cuins₂ And Cuinse₂ Light-Absorbing Thin Films For Use In Solar Cells, Amy R. Tapley
Electronic Thesis and Dissertation Repository
Solar energy is free and globally abundant and harnessed cost-effectively, it has the potential to be the world’s main source of energy. CuInGa(S,Se)2 solar cells have a very high efficiency of 20 %. However, gallium is a rare and expensive element. We have decided to work on its alternative CuInSe2 (CISe) and CuInS2 (CIS) by removing gallium or both gallium and selenium. The p-type CISe or CIS light-absorbing semiconducting layer is crucial for this type of solar cell. Preparation methods for CIS and CISe films were developed to reduce the costs and enhance the photoelectrochemical ...
Heterojunction Engineering For Next Generation Hybrid Ii-Vi Materials, 2017 The Graduate Center, City University of New York
Heterojunction Engineering For Next Generation Hybrid Ii-Vi Materials, Thor Garcia
All Dissertations, Theses, and Capstone Projects
Molecular Beam Epitaxy(MBE) is a versatile thin film growth technique with monolayer control of crystallization. The flexibility and precision afforded by the technique allows for unique control of interfaces and electronic structure of the films grown. This facilitates the realization of novel devices and structures within a research environment normally only achieved though complex industrial processes. In the past, the control of each interface in MBE has been explored to great benefit. In this work, we study the control of these interfaces so as to increase the performance of novel devices material systems. This dissertation focuses on two main ...
Interfacial Charge Distributions In Carbon-Supported Palladium Catalysts, 2017 Iowa State University
Interfacial Charge Distributions In Carbon-Supported Palladium Catalysts, Radhika Rao, Raoul Blume, Thomas W. Hansen, Erika Fuentes, Kathleen Dreyer, Simona Moldovan, Ovidiu Ersen, David D. Hibbitts, Yves J. Chabal, Robert Schlögl, Jean-Philippe Tessonnier
Chemical and Biological Engineering Publications
Controlling the charge transfer between a semiconducting catalyst carrier and the supported transition metal active phase represents an elite strategy for fine turning the electronic structure of the catalytic centers, hence their activity and selectivity. These phenomena have been theoretically and experimentally elucidated for oxide supports but remain poorly understood for carbons due to their complex nanoscale structure. Here, we combine advanced spectroscopy and microscopy on model Pd/C samples to decouple the electronic and surface chemistry effects on catalytic performance. Our investigations reveal trends between the charge distribution at the palladium–carbon interface and the metal’s selectivity for ...
Nonlinear Oscillatory Dynamics Of The Hardening Of Calcium Phosphate Bone Cements, 2017 Chapman University
Nonlinear Oscillatory Dynamics Of The Hardening Of Calcium Phosphate Bone Cements, Vuk Uskoković, Julietta V. Rau
Pharmacy Faculty Articles and Research
Here we report on the nonlinear, oscillatory dynamics detected in the evolution of phase composition during the setting of different calcium phosphate cements, two of which evolved toward brushite and one toward hydroxyapatite as the final product. Whereas both brushite-forming cements contained iondoped b-tricalcium phosphate as the initial phase, the zinc-containing one yielded scholzite as an additional phase during setting and the oscillations between these two products were pronounced throughout the entire 80 h setting period, long after the hardening processes was over from the mechanical standpoint. Oscillations in the copper-containing system involved the amount of brushite as the main ...
Renewable Hydrogels From Norbornene-Functionalized Carboxymethyl Cellulose And A Short Dithiol Crosslinked Via A Thiol-Ene Reaction, Thomas Mcoscar
Electronic Theses and Dissertations
Cellulose-based hydrogels - three dimensional "solid" structures composed primarily of liquid water and held together by an interconnected polymer network - were created by first functionalizing carboxymethyl cellulose (CMC), a cellulose derivative, with carbic anhydride in a basic aqueous reaction with the intent of developing novel hydrogels from renewable materials. The product of this reaction, carbic CMC (cCMC), had a new norbornene group as a subsection of the carbic group. Norbornene is a reactive alkene structure that allows for further chemistry with cCMC, such as crosslinking. cCMC was crosslinked with 2,2'-(ethylenedioxy)diethathiol to create hydrogels using a water-soluble, UV-sensitive radical ...
How Strongly Do Oysters Stick?, 2017 Universidad de Los Andes - Colombia
How Strongly Do Oysters Stick?, Nicolás M. Morato, Andrés M. Tibabuzo, Jonathan J. Wilker
The Summer Undergraduate Research Fellowship (SURF) Symposium
Biological adhesives are a type of interfacial material that has incredible potential to generate new biomimetic compounds that can replace current strong, but toxic, adhesives. Therefore, a study of the chemical composition and mechanical properties of those bio-adhesives is necessary. However, in the case of oysters, despite known chemical characterization of the adult’s adhesive, there are almost no studies on its mechanical properties. Furthermore, there is no available information on the adhesive properties of spat (oysters in their larvae state). Herein, we present the first mechanical characterization of the spat adhesive, measuring its adhesion strength by hydrodynamic determination using ...