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Title: A study of the effect of the hydrophobicity of organic compounds on their micelle-water partition coefficients in aqueous solutions of cetyltrimethylammonium bromide.
Creator: Vijayabhaskar, C. R., Florida Atlantic University, Haky, Jerome E.
Abstract/Description: The effect of the hydrophobicity of organic compounds on their micelle-water partition coefficients was investigated. The micelle-water partition coefficients were obtained by UV/VIS spectroscopy and correlated with their octanol-water partition coefficients. The octanol-water partition coefficient of an organic compound is a measure of its hydrophobicity. Hydrophobicity alone did not influence the micelle-water partition coefficients. Further research is required to substantiate present...
Show moreThe effect of the hydrophobicity of organic compounds on their micelle-water partition coefficients was investigated. The micelle-water partition coefficients were obtained by UV/VIS spectroscopy and correlated with their octanol-water partition coefficients. The octanol-water partition coefficient of an organic compound is a measure of its hydrophobicity. Hydrophobicity alone did not influence the micelle-water partition coefficients. Further research is required to substantiate present findings and obtain additional related information.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/15000
Subject Headings: Hydrophobic surfaces, Micelles, Surface chemistry, Surface active agents, Detergents
Format: Document (PDF)

$Low energy electron diffraction determination of the surface structures formed by the carbon monoxide chemisorption on the nickel(110) surface$

Title: Low energy electron diffraction determination of the surface structures formed by the carbon monoxide chemisorption on the nickel(110) surface.
Creator: Zhao, Changyi, Florida Atlantic University, Passler, Mark A.
Abstract/Description: Low Energy Electron Diffraction is used to determine the different structures formed by the CO adsorption on the Ni(110) surface at two coverages. At full coverage the superlattice is Ni(110)-(2 x 1)2CO. For this superlattice, the CO molecules adsorb at the short bridge sites with a 20 degrees common tilt in the +-[001] directions. The Ni-C and the C-O bond lengths are 1.85 A and 1.15 A, respectively. In the Ni(110)-c(2 x 4)3CO superlattice structure, which is formed at an intermediate...
Show moreLow Energy Electron Diffraction is used to determine the different structures formed by the CO adsorption on the Ni(110) surface at two coverages. At full coverage the superlattice is Ni(110)-(2 x 1)2CO. For this superlattice, the CO molecules adsorb at the short bridge sites with a 20 degrees common tilt in the +-[001] directions. The Ni-C and the C-O bond lengths are 1.85 A and 1.15 A, respectively. In the Ni(110)-c(2 x 4)3CO superlattice structure, which is formed at an intermediate coverage, the CO molecules adsorb at the top sites with two types of configurations on alternate (110) rows. Half the rows are filled with CO molecules having a 9 degrees zig-zag common tilt in the $\pm$ (001) directions, and half the rows are half filled with untilted CO molecules. The Ni-C and the C-O bond lengths are 1.67 A and 1.15 A, respectively. The possible role of hydrogen in the formation of the surface structure is discussed.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14934
Subject Headings: Low energy electron diffraction, Surfaces (Physics), Surface chemistry, Chemisorption
Format: Document (PDF)

$Low energy electron diffraction (LEED) determination of surface structure applied to nickel(110)-nitric oxide and to the martensitic alloy iron-33 percent nickel(111)$

Title: Low energy electron diffraction (LEED) determination of surface structure applied to nickel(110)-nitric oxide and to the martensitic alloy iron-33 percent nickel(111).
Creator: Fan, Zeyuan, Florida Atlantic University, Passler, Mark A.
Abstract/Description: The purpose of this thesis is to provide a comprehensive overview of an important technique (low energy electron diffraction) used in the study of surface phenomena. Within this context, the LEED studies of NO adsorbed on the Ni(110) surface and of Fe-33%Ni(111) near its Martensitic transition temperature were done to determine their surface structures.
Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14765
Subject Headings: Surfaces (Physics), Low energy electron diffraction, Surface chemistry
Format: Document (PDF)

Title: Charge Regulation of a Surface Immersed in an Electrolyte Solution.
Creator: Acharya, Pramod, Lau, Andy W. C., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: In this thesis, we investigate theoretically a new model of charge regulation of a single charged planar surface immersed in an aqueous electrolyte solution. Assuming that the adsorbed ions are mobile in the charged plane, we formulate a field theory of charge regulation where the numbers of adsorbed ions can be determined consistently by equating the chemical potentials of the adsorbed ions to that of the ions in the bulk. We analyze the mean-field treatment of the model for electrolyte of...
Show moreIn this thesis, we investigate theoretically a new model of charge regulation of a single charged planar surface immersed in an aqueous electrolyte solution. Assuming that the adsorbed ions are mobile in the charged plane, we formulate a field theory of charge regulation where the numbers of adsorbed ions can be determined consistently by equating the chemical potentials of the adsorbed ions to that of the ions in the bulk. We analyze the mean-field treatment of the model for electrolyte of arbitrary valences, and then beyond, where correlation effects are systematically taken into account in a loop expansion. In particular, we compute exactly various one-loop quantities, including electrostatic potentials, ion distributions, and chemical potentials, not only for symmetric (1, 1) electrolyte but also for asymmetric (2, 1) electrolyte, and make use of these quantities to address charge regulation at the one-loop level. We find that correlation effects give rise to various phase transitions in the adsorption of ions, and present phase diagrams for (1, 1) and (2, 1) electrolytes, whose distinct behaviors suggest that charge regulation, at the one-loop level, is no longer universal but depends crucially on the valency of the ions.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004560, http://purl.flvc.org/fau/fd/FA00004560
Subject Headings: Surface chemistry., Intermolecular forces., Electrodynamics., Quantum field theory.
Format: Document (PDF)

Title: The effects of nitric acid and silane surface treatments on carbon fibers and carbon/vinyl ester composites before and after seawater exposure.
Creator: Langston, Tye A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research focuses on carbon fiber treatment by nitric acid and 3- (trimethoxysilyl)propyl methacrylate silane, and how this affects carbon/vinyl ester composites. These composites offer great benefits, but it is difficult to bond the fiber and matrix together, and without a strong interfacial bond, composites fall short of their potential. Silanes work well with glass fiber, but do not bond directly to carbon fiber because its surface is not reactive to liquid silanes. Oxidizing surface...
Show moreThis research focuses on carbon fiber treatment by nitric acid and 3- (trimethoxysilyl)propyl methacrylate silane, and how this affects carbon/vinyl ester composites. These composites offer great benefits, but it is difficult to bond the fiber and matrix together, and without a strong interfacial bond, composites fall short of their potential. Silanes work well with glass fiber, but do not bond directly to carbon fiber because its surface is not reactive to liquid silanes. Oxidizing surface treatments are often prescribed for improved wetting and bonding to carbon, but good results are not always achieved. Furthermore, there is the unanswered question of environmental durability. This research aimed to form a better understanding of oxidizing carbon fiber treatments, determine if silanes can be bonded to oxidized surfaces, and how these treatments affect composite strength and durability before and after seawater exposure. Nitric acid treatments on carbon fibers were found to improve their tensile strength to a constant level by smoothing surface defects and chemically modifying their surfaces by increasing carbonyl and carboxylic acid concentrations. Increasing these surface group concentrations raises fiber polar energy and causes them to cohere. This impedes wetting, resulting in poor quality, high void content composites, even though there appeared to be improved adhesion between the fibers and matrix. Silane was found to bond to the oxidized carbon fiber surfaces, as evidenced by changes in both fiber and composite properties. The fibers exhibited low polarity and cohesion, while the composites displayed excellent resin wetting, low void content, and low seawater weight gain and swelling. On the contrary, the oxidized fibers that were not treated with silane exhibited high polarity and fiber cohesion., Their composites displayed poor wetting, high void content, high seawater weight gain, and low swelling. Both fiber treatment types resulted in great improvements in dry transverse tensile strength over the untreated fibers, but the oxidized fiber composites lost strength as the acid treatment time was extended, due to poor wetting. The acid/silane treated composites lost some transverse tensile strength after seawater exposure, but the nitric acid oxidized fiber composites appeared to be more seawater durable.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/172669
Subject Headings: Silane compounds, Testing, Surface chemistry, Composite materials, Biodegradation, Carbon compounds, Testing
Format: Document (PDF)

Title: A study of the effects of nanoparticle modification on the thermal, mechanical and hygrothermal performance of carbon/vinyl ester compounds.
Creator: Powell, Felicia M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Enhancement of mechanical, thermal and hygrothermal properties of carbon fiber/vinyl ester (CFVE) composites through nanoparticle reinforcement has been investigated. CFVE composites are becoming more and more attractive for marine applications due to two reasons : high specific strength and modulus of carbon fiber and low vulnerability of vinyl ester resin to sea water. However, the problem with this composite system is that the fiber matrix (F/M) interface is inherently weak. This leads to...
Show moreEnhancement of mechanical, thermal and hygrothermal properties of carbon fiber/vinyl ester (CFVE) composites through nanoparticle reinforcement has been investigated. CFVE composites are becoming more and more attractive for marine applications due to two reasons : high specific strength and modulus of carbon fiber and low vulnerability of vinyl ester resin to sea water. However, the problem with this composite system is that the fiber matrix (F/M) interface is inherently weak. This leads to poor mechanical properties and fast ingress of water at the interface further deteriorating the properties. This investigation attempts to address these deficiencies by inclusion of nanoparticles in CFVE composites. Three routes of nanoparticle reinforcement have been considered : nanoparticle coating of the carbon fiber, dispersion of nanoparticles in the vinyl ester matrix, and nanoparticle modification of both the fiber and the matrix. Flexural, short beam shear and tensile testing was conducted after exposure to dry and wet environments. Differential scanning calorimetry and dynamic mechanical analysis were conducted as well. Mechanical and thermal tests show that single inclusion of nanoparticles on the fiber or in the matrix increases carbon/vinyl ester composite properties by 11-35%. However, when both fiber and matrix were modified with nanoparticles, there was a loss of properties.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352286
Subject Headings: Composite materials, Mechanical properties, Nanostructured materials, Testing, Carbon compounds, Testing, Fibrous composites, Testing, Surface chemistry
Format: Document (PDF)

Title: Chemical Method and Device to Detect Underwater Trace Explosives via Photo-Luminescence.
Creator: Langston, Tye A., Florida Atlantic University, Granata, Richard D., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research tests the use of sensitized lanthanide ions to determine if they can detect water-borne explosive traces and produces two designs for a field-deployable underwater explosive trace detector. 1,1 0-phenanthroline and thenoyltritluoroacetone are evaluated as sensitizing ligands to absorb energy and initiate the fluorescence process in europium ions. Different compounds obtained via ligand choice and mixing order are evaluated for their ability to produce a large fluorescence...
Show moreThis research tests the use of sensitized lanthanide ions to determine if they can detect water-borne explosive traces and produces two designs for a field-deployable underwater explosive trace detector. 1,1 0-phenanthroline and thenoyltritluoroacetone are evaluated as sensitizing ligands to absorb energy and initiate the fluorescence process in europium ions. Different compounds obtained via ligand choice and mixing order are evaluated for their ability to produce a large fluorescence differential between explosive-laden and explosive-absent solutions. Optimal excitation and emission wavelengths for several different compounds are determined, as well as practical wavelengths to be applied in the field. The effect of methanol as a solvent to deliver the reagents is evaluated and rough solubility limits are determined. The effects of seawater constituents on detection are investigated and explosive detection limits are determined. It was found that this method and device are viable for underwater explosive trace detection. A field-deployable device is designed, characterized, and proven.
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Date Issued: 2006
PURL: http://purl.flvc.org/fau/fd/FA00012600
Subject Headings: Silane compounds--Testing, Surface chemistry, Composite materials--Biodegradation, Carbon compounds--Testing
Format: Document (PDF)

Title: Effects of POSS Fiber Sizing on the Mechanical and Thermal Properties of CarbonNinyl Ester Composites.
Creator: Powell, Felicia M., Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The degradation of polymer composites in moist environments is a limiting factor in the advancement of composite technology. The key to mitigate this degradation is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by treating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). Two POSS systems, namely octaisobutyl and trisilanolphenyl, have been investigated. A set of chemical and...
Show moreThe degradation of polymer composites in moist environments is a limiting factor in the advancement of composite technology. The key to mitigate this degradation is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by treating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). Two POSS systems, namely octaisobutyl and trisilanolphenyl, have been investigated. A set of chemical and mechanical procedures has been developed to coat carbon fibers with POSS, and fabricate layered composites using vinyl ester resin. lnterlaminar shear, transverse tension, and low velocity impact tests on composites have indicated around 10-38% improvement in mechanical properties with respect to control samples. Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) tests have also shown significant improvement in glass transition temperature (T9). Hygrothermal tests, under various environments, have demonstrated that POSS reduces water absorption by 20-30%.
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Date Issued: 2009
PURL: http://purl.flvc.org/fau/fd/FA00012540
Subject Headings: Surface chemistry, Composite materials--Biodegradation, Carbon compounds--Testing, Thermodynamics, Fibrous compounds--Testing
Format: Document (PDF)

Title: Crystallographic finite element modeling for dislocation generation in semiconductor crystals grown by VGF process.
Creator: Sheu, Gary., Florida Atlantic University, Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The generation and multiplication of dislocations in Gallium Arsenide (GaAs) and Indium Phosphide (InP) single crystals grown by the Vertical Gradient Freeze (VGF) process is predicted using a transient crystallographic finite element model. This transient model is developed by coupling microscopic dislocation motion and multiplication to macroscopic plastic deformation in the slip system of the grown crystals during their growth process. During the growth of InP and GaAs crystals,...
Show moreThe generation and multiplication of dislocations in Gallium Arsenide (GaAs) and Indium Phosphide (InP) single crystals grown by the Vertical Gradient Freeze (VGF) process is predicted using a transient crystallographic finite element model. This transient model is developed by coupling microscopic dislocation motion and multiplication to macroscopic plastic deformation in the slip system of the grown crystals during their growth process. During the growth of InP and GaAs crystals, dislocations are generated in plastically deformed crystal as a result of crystallographic glide caused by excessive thermal stresses. The temperature fields are determined by solving the partial differential equation of heat conduction in a VGF crystal growth system. The effects of growth orientations and growth parameters (i.e., imposed temperature gradients, crystal radius and growth rate) on dislocation generation and multiplication in GaAs and InP crystals are investigated using the developed transient crystallographic finite element model. Dislocation density patterns on the cross section of GaAs and InP crystals are numerically calculated and compared with experimental observations. For crystals grown along [001] and [111] orientations, the results show that more dislocations are generated as the temperature gradient, the crystal growth rate and the crystal radius increase. For the same growth process, it shows that the crystal grown along [111] orientation is a favorable growth direction to grow lower dislocation density crystals. All the results show a famous "W" shape and four fold symmetry dislocation density pattern in GaAs and InP crystals grown from both orientations regardless of crystal growth parameters, which agree well with the patterns observed in actual grown crystals. Therefore, this developed crystallographic model can be employed by crystal grower to design an optimal growth parameters and orientations for growing low dislocation density in advanced semiconductor and optical crystals.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12171
Subject Headings: Surface chemistry, Gallium arsenide semiconductors, Dislocations in crystals, Crystal growth, Semiconductors--Materials
Format: Document (PDF)

Surface chemistry (8)	+ -
Carbon compounds (2)	+ -
Carbon compounds--Testing (2)	+ -
Composite materials (2)	+ -
Composite materials--Biodegradation (2)	+ -

Low energy electron diffraction (2)	+ -
Surfaces (Physics) (2)	+ -
Testing (2)	+ -
Biodegradation (1)	+ -
Chemisorption (1)	+ -
Crystal growth (1)	+ -
Detergents (1)	+ -
Dislocations in crystals (1)	+ -
Electrodynamics. (1)	+ -
Fibrous composites (1)	+ -
Fibrous compounds--Testing (1)	+ -
Gallium arsenide semiconductors (1)	+ -
Hydrophobic surfaces (1)	+ -
Intermolecular forces. (1)	+ -
Mechanical properties (1)	+ -
Micelles (1)	+ -
Nanostructured materials (1)	+ -
Quantum field theory. (1)	+ -
Semiconductors--Materials (1)	+ -
Silane compounds (1)	+ -
Silane compounds--Testing (1)	+ -
Surface active agents (1)	+ -
Surface chemistry. (1)	+ -
Thermodynamics (1)	+ -

Florida Atlantic University (7)	+ -
College of Engineering and Computer Science (5)	+ -
Department of Ocean and Mechanical Engineering (5)	+ -
Langston, Tye A. (2)	+ -
Passler, Mark A. (2)	+ -

Powell, Felicia M. (2)	+ -
Acharya, Pramod (1)	+ -
Charles E. Schmidt College of Science (1)	+ -
Department of Physics (1)	+ -
Fan, Zeyuan (1)	+ -
Granata, Richard D. (1)	+ -
Haky, Jerome E. (1)	+ -
Lau, Andy W. C. (1)	+ -
Mahfuz, Hassan (1)	+ -
Sheu, Gary. (1)	+ -
Tsai, Chi-Tay (1)	+ -
Vijayabhaskar, C. R. (1)	+ -
Zhao, Changyi (1)	+ -

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