An Electrochemical Investigation In The Anticorrosive Properties Of Silver Nanoparticles For The Acidic Corrosion Of Aluminium,
2018
Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321, EGYPT;
An Electrochemical Investigation In The Anticorrosive Properties Of Silver Nanoparticles For The Acidic Corrosion Of Aluminium, H. A. Fetouh, B. A. Abd-El-Nabey, Y. M. Goher, M. S. Karam
Journal of Electrochemistry
The mass loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used for the determinations of the corrosion rates for aluminium in 1.0 mol·L-1 hydrochloric acid (HCl) solutions both in the absence and presence of silver nanoparticles (SNPs) at 30 ℃. The protection efficiency was evaluated to be 96.4% for 0.014 g·L-1 of the SNPs. It has been found that the capacity of the electrical double layer at the aluminium/solution interface was decreased with increasing the concentration of the SNPs, indicating that the SNPs were adsorbed at the aluminium surface. The Langmuir adsorption isotherm and the kinetic-thermodynamic …
Systematic Size Control In The Synthesis Of Zero-Valent Iron Nanoparticles,
2018
University of New Mexico
Systematic Size Control In The Synthesis Of Zero-Valent Iron Nanoparticles, Grant C. Bleier
Chemistry and Chemical Biology ETDs
A novel synthetic method for the production of highly magnetic, low size-dispersity nanoparticles through reversible magnetic agglomeration is introduced and studied in detail. Initially, a weakly coordinating surfactant (3-octadecyl-2,4-pentanedione) is employed to produce a wide range of nanoparticle sizes ranging from 8 to 20 nm in diameter. The kinetics faced in these reactions by cheap and widely available iron complex precursors can be avoided in this method with the introduction of thermodynamic control, which occurs in the form of a magnetic precipitation event that essentially halts nanoparticle growth. Utilizing this synthetic method, the length of the alkyl chain on the …
Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity,
2018
CUNY Graduate Center
Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li
Dissertations, Theses, and Capstone Projects
For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO2 electrochemical reduction reaction (CO2ERR). The Faradaic efficiencies (FE) of CO and CH4 formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH4 formation of 29% and 0.76%, respectively. It was found that the overall performance in CO2ERR dramatically increased upon the reduction pretreatment of the carbons in N2-saturated electrolyte before the CO2 reduction process. The pretreated carbon showed the maximum FE of CO …
Biomedical Applications Of Hydrogels And Gumbos,
2018
Louisiana State University and Agricultural and Mechanical College
Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth Mcneel
LSU Doctoral Dissertations
Sodium deoxycholate (NaDC) is a small bile salt that was used in this dissertation to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC. These solutions respectively yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), …
Structural Evolution Of Gold-Doped Bismuth Clusters AubiN– (N = 4−8),
2018
University of Nebraska - Lincoln
Structural Evolution Of Gold-Doped Bismuth Clusters AubiN– (N = 4−8), Seema Pande, Tian Jian, Navneet S. Khetrapal, Lai-Sheng Wang, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
The structures of gold-doped bismuth clusters, AuBin− (n = 4−8), are investigated through a joint photoelectron spectroscopy and density functional theory (DFT) study. Well-resolved photoelectron spectra are obtained at several photon energies. Global minimum searches coupled with DFT calculations yield low-lying structures, whose relative energies are further evaluated by single-point energy calculations at the CCSD(T) level of theory. Vertical detachment energies are calculated with the inclusion of spin−orbit effects to compare with the experimental data. Three-dimensional structures are found to be dominant in this size range, while a planar low-lying isomer is observed only for AuBi4 …
Probing The Surface Of Nanodiamonds At Stanford Synchrotron Radiation Lightsource And San Jose State University,
2018
San Jose State University
Probing The Surface Of Nanodiamonds At Stanford Synchrotron Radiation Lightsource And San Jose State University, Jocelyn Valenzuela, Jackson Earl, Cynthia Melendrez, Grace Jeanpierre, Dennis Nordlund, Abraham Wolcott
STAR Program Research Presentations
The nitrogen-vacancy center in diamond is a promising tool in oncology, electric field sensing, and quantum cryptography. High-pressure high-temperature (HPHT) nanodiamonds (NDs) are prime contenders for these fields because they host nitrogen-vacancy centers (NVCs) which are applicable towards cancer detection and electric and magnetic field sensing. However, to apply HPHT NDs to these fields, the surface must first be functionalized—a difficult process because of the inert nature of the surface. The project at hand focuses on surface modification of HPHT NDs with amines to allow for further bioconjugation of small molecules and plasmonic shells. This is done via liquid-phase chemistry …
Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts
Chemistry Publications
Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing …
Surfactant Driven Assembly Of Freeze-Casted, Polymer-Derived Ceramic Nanoparticles On Grapehene Oxide Sheets For Lithium-Ion Battery Anodes,
2018
University of Central Florida
Surfactant Driven Assembly Of Freeze-Casted, Polymer-Derived Ceramic Nanoparticles On Grapehene Oxide Sheets For Lithium-Ion Battery Anodes, Ali Zein Khater
Honors Undergraduate Theses
Traditional Lithium-Ion Batteries (LIBs) are a reliable and cost-efficient choice for energy storage. LIBs offer high energy density and low self-discharge. Recent developments in electric-based technologies push for replacing historically used Lead-Acid batteries with LIBs. However, LIBs do not yet meet the demands of modern technology. Silicon and graphene oxide (GO) have been identified as promising replacements to improve anode materials. Graphene oxide has a unique sheet-like structure that provides a mechanically stable, light weight material for LIB anodes. Due to its structure, reduced graphene oxide (rGO) is efficiently conductive and resistive to environmental changes. On the other hand, silicon-based …
Biosensing And Catalysis Applications Of Nanoporous Gold (Npg) And Platinum-Speckled Nanoporous Gold (Npg-Pt) Electrodes,
2018
Virginia Commonwealth University
Biosensing And Catalysis Applications Of Nanoporous Gold (Npg) And Platinum-Speckled Nanoporous Gold (Npg-Pt) Electrodes, Christopher J. Freeman
Theses and Dissertations
The importance of porous materials has risen substantially in the last few decades due to their ability to reduce the size and cost of bioanalytical devices and fuel cells. First, this work aims to describe the fabrication of nanoporous gold (NPG) electrodes that are resistant to electrode passivation due to fibrinogen biofouling in redox solutions. The effect on potentiometric and voltammetric experiments was seen as a deviation from ideal behavior on planar gold electrodes, whereas NPG electrodes were consistently behaving in a Nernstian fashion at low concentrations of ferri-ferrocyanide (£100 mM). An improvement in electrode behavior on NPG electrodes versus …
Synthesis And Characterization Of Magnetic Cabides And Oxides Nanomaterials,
2018
Virginia Commonwealth University
Synthesis And Characterization Of Magnetic Cabides And Oxides Nanomaterials, Hei Man Tsui
Theses and Dissertations
The design and development of nanoparticles is of great interest in the current energy and electronic industry. However, based on the current materials available the production cost can be high with insignificant magnetic and mechanical properties. Specifically, rare-earth magnetic materials composed of neodymium and samarium are known for their high magnetic performance, however, due to the cost of development there is a need to develop a versatile and cost effective material. Alternatively, cobalt carbide nanomaterials have shown to be a promising alternative for rare-earth free magnets as they exhibit comparable properties as hexaferrite magnetic materials. The primary goal of this …
New And Optimized Green Synthesis Of Silver Nanoparticles Using Mullein,
2018
University of Alabama in Huntsville
New And Optimized Green Synthesis Of Silver Nanoparticles Using Mullein, Marisa Thompson, Cuong Nguyen, Anna Holmes
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Richard Smalley And The Materials Of Tomorrow: The Discovery, Properties, And Science Of Fullerenes,
2018
Parkland College
Richard Smalley And The Materials Of Tomorrow: The Discovery, Properties, And Science Of Fullerenes, Creighton A. Jackson
Natural Sciences Student Research Presentations
These are slides accompanying a presentation given at the Natural Sciences Poster Session at Parkland College outlining the properties of and ongoing research pertaining to fullerenes in materials science.
Lignin Depolymerization: Mechanistic Analysis, Optimization And Application,
2018
South Dakota State University
Lignin Depolymerization: Mechanistic Analysis, Optimization And Application, Eric Michael Nagel
Electronic Theses and Dissertations
Lignin is the most abundant aromatic biopolymer and is a potential source for phenolic chemical feedstocks. Lignin is composed of phenolic units connected by more than eight different linkages, the most common being β-O-4 which constitutes 50-60%. The hydrothermal decomposition of a guaiacol based β-O-4 lignin dimer was studied under neutral and basic conditions to elucidate the mechanism of β-O-4 bond cleavage and the formation of downstream products. Phenol-carbonyl condensation and vinyl-ether formation were shown to be the primary causes for low monomer yields under the tested conditions. Three Ni catalyst systems, Ni/C + H2, Ni/C-Zn, and Ni/Zn, …
Crystallographically Defined Silicon Macropore Membranes,
2018
Renaissance Academy Charter School, Phoenixville, PA
Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski
Chemistry Faculty Publications
Laser ablation with nanosecond-pulsed Nd:YAG laser irradiation combined with anisotropic alkaline etching of Si wafers creates 4–20 µm macropores that extend all the way through the wafer. The walls of these macropores are crystallographically defined by the interaction of the anisotropy of the etchant with the orientation of the single-crystal silicon substrate: rectangular/octagonal on Si(001), parallelepiped on Si(110), triangular/hexagonal on Si(111). Laser ablation can create pillars with peak-tovalley heights of over 100 µm. However, with nanosecondpulsed irradiation at 532 nm, the majority of this height is created by growth above the original plane of the substrate whereas for 355 nm …
Plume And Nanoparticle Formation During Laser Ablation,
2018
West Chester University of Pennsylvania
Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei
Chemistry Faculty Publications
The processes that lead to material ejection when a solid sample is irradiated near and above the pulsed laser ablation threshold are discussed. Emphasis is placed on the thermal and mechanical mechanisms that occur during pulsed laser irradiation of metals and semiconductors. Distinctions are drawn between ultrafast-pulsed irradiation, which occurs under stress confinement, and shortpulsed irradiation, in which stress is released during the laser pulse. Similarly, the distinctions between the spallation and phase explosion regimes are discussed. Spallation is only possible when the time of the laser heating is shorter than the time needed for mechanical equilibration of the heated …
Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace),
2018
West Chester University of Pennsylvania
Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen
Chemistry Faculty Publications
ReEtching produces nanostructured silicon when a catalytic agent, e.g. dissolved V2O5, is used to facilitate etching between Si and H2O2. H2O2 regenerates dissolved V in a 5+ oxidation state, which initiates etching by injecting holes into the Si valence band. Independent control over the extent of reaction (controlled by the amount of H2O2 added) and the rate of reaction (controlled by the rate at which H2O2 is pumped into the etchant solution) allows us to porosify Si substrates of arbitrary size, shape and doping, including wafers, single-crystal powders, polycrystalline powders, metallurgical grade powder, Si nanowires, Si pillars and Si powders …
Silicon Surface Photochemistry,
2018
West Chester University of Pennsylvania
Silicon Surface Photochemistry, Kurt W. Kolasinski
Chemistry Faculty Publications
General concepts of photochemistry on metal and semiconductor surfaces are elucidated. These concepts are then applied more specifically to describe photochemical transformation of molecules on and with silicon surfaces. The mechanisms by which light can induce chemical reactions following electronic excitation are described. Processes reviewed include photodissociation of adsorbed molecules, photo-induced attachment of organic molecules and photo-induced corrosion.
Interfacial Corrosion Of Copper And The Formation Of Copper Hydroxychloride,
2018
The University of Akron
Interfacial Corrosion Of Copper And The Formation Of Copper Hydroxychloride, Mary Teague, Shengxi Li, Hongbo Cong
Williams Honors College, Honors Research Projects
Electrical circuitry is an industry, among many others, heavily using the element of copper. Ensuring the mechanical integrity of Cu is crucial, especially in salt environments, for the multifaceted composition of circuits. 4N NaCl solution (equilibrium concentration in ~84% RH) simulated this three-phase system. Rectangular Cu samples were partially immersed in both ambient and continuous lab air sparging atmospheres to understand waterline corrosion of the metal. Open circuit potentials (OCP) were continuously taken during the immersion testing for a maximum of 5 days. A scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), Raman spectroscopy, and 3-D …
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
Department of Food Science and Technology: Faculty Publications
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%, 225%, 56.67%, 9.62m2 g …
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 carbon monoxide …
