Physical Sciences and Mathematics Commons^™

Surface Modification Of Pigments And Its Role In Offset Ink Setting, Wei Gu

Electronic Theses and Dissertations

Ink setting affects offset print quality issues such as print mottle and print gloss. It is known that ink setting depends on many factors, such as the nature of the substrate, the properties of the coating, and the ink formulation. However, the role of pigment surface chemistry in offset ink setting is unknown. From an experimental perspective, it is difficult to determine the role of the surface chemistry as it requires paper coatings that are similar in physical properties and differ only in the pigment surface chemistry. The aim of this study was two-fold. The first was to apply methods …

Production Of Ethanol From Hardwood, Jay Mitchell

Electronic Theses and Dissertations

Diminishing crude oil and natural gas supplies, along with concern about greenhouse gas are major driving forces in the search for efficient renewable energy sources. The conversion of lignocellulosic biomass to energy and useful chemicals is a component of the solution. Ethanol is most commonly produced by enzymatic hydrolysis of complex carbohydrates to simple sugars followed by fermentation using yeast.

C₆H_l0O₅ + H₂O −Enxymes→ C₆H₁₂O₆ −Yeast→ 2CH₃CH₂OH + 2C0₂

In the U.S. corn is the primary starting raw material for commercial ethanol production. …

A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu

Electronic Theses and Dissertations

Our interest in studying reactions catalyzed by high surface area W0₃ powders is based on their potential application as the active material in sensors for low level (ppb) detection of flammable or toxic gases. A series of porous W0₃ powders with both meso- and micro-porosity have been synthesized by Waghe and Tripp. Preliminary results of the response of sensors fabricated from these materials indicated the possibility of size selectivity on the molecular scale. To provide support for the hypothesis of size selectivity and understand the reaction kinetics of alcohols over the new porous W0₃ powders for sensor …

Ir Studies Of The Interaction Of Surfactants And Polyelectrolytes Adsorbed On Tio2 Particles, Haiyan Li

Electronic Theses and Dissertations

Polymers/surfactants are used to control and modify the interfacial properties of particulate suspensions. The resulting properties are dependent on the amount of adsorbed surfactants/polymers on the surface as well as the nature of the aggregated structures. Often these interactions are complex and not well understood. In this thesis we have used Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) to identify surfactant, mixed surfactant, polyelectrolyte and mixed polyelectrolyte surfactant structures formed on charged Ti0₂ particles. In addition, the change occurring to the structure of an adsorbed polymer layer on Ti0₂ to flowing suspension of silica particles was studied. A …

Mechanistic Studies Of The Oxidation Of Lignin And Cellulose Models, Oh-Kyu Lee

Electronic Theses and Dissertations

Oxygen delignification is an environmentally friendly pulp bleaching system. To develop a selective delignification process that results in high DP retention of carbohydrate with lignin being removed, obtaining better knowledge of reactions occurring during oxygen delignification is essential.

In this work, mixtures of guaiacol (model lignin) and methyl-ß-D-glucoside (model cellulose) were reacted in a pressurized oxygen reaction system (pH 12,65 psi O₂, and 95°C in a glass reaction vessel). In the results, methyl-ß-D-glucoside degraded only in the presence of lignin. This indicates that hydroxyl radicals, that subsequently react with methyl-ß-D-glucoside, are generated in the system. Unfortunately, we could …

Effects Of Fiberimatiux Interactions On The Interfacial Deformation Micromechanics Of Cellulose-Fiberipolymer Composites, William Tai-Yin Tze

Electronic Theses and Dissertations

The overall objective of this dissertation was to gain an understanding of the relationship between interfacial chemistry and the micromechanics of the cellulose-fiber/polymer composites. Regenerated cellulose (lyocell) fibers were treated with amine-, phenylamine-, phenyl-, and octadecyl-silanes, and also styrene-maleic anhydride copolymer. Inverse gas chromatography was conducted to evaluate the modified surfaces and to examine the adsorption behavior of ethylbenzene, a model compound for polystyrene, onto the fibers. Micro-composites were formed by depositing micro-droplets of polystyrene onto single fibers. The fiber was subjected to a tensile strain, and Raman spectroscopy was employed to determine the point-to-point variation of the strain- and …

Synthesis Of Porous Monoclinic Tungsten Oxides And Their Application In Sensors, Anil Bhalchandra Waghe

Electronic Theses and Dissertations

Semiconducting metal oxide sensors are limited in their usage because of their poor detection selectivity. The current approach to achieve better selectivity in SMO detection uses prefiltering/preconcentration schemes to reduce the number of gases in contact with the sensor in combination with array-based detection. In this thesis we have investigated different materials and approaches for use as elements in an array based detection system.

One approach we have investigated involves the use of porous monoclinic WO₃ to obtain size selectivity in detection within the sensing element itself. In chapter 3 we describe the synthetic protocol used to generate high …

Reactions Of Alcohols And Organophosphonates On Tungsten Trioxide Epitaxial Films, Shuguo Ma

Electronic Theses and Dissertations

The adsorption, diffusion, reactions, and desorption of water, alcohols, ethers, and an organophosphonate were studied using calibrated thermal desorption spectroscopy (CTDS) on thin film WO₃(OOl) surfaces grown epitaxially on a single crystal α- Al₂O₃(li02) (sapphire) substrate. The studies were conducted on oxidized and reduced surfaces, which were characterized by x-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The desorption spectra for molecular desorption of all of these molecules shifted to lower temperature with increasing coverage, and had overlapping tails on the high temperature side. Monte Carlo simulations show that this typical desorption shape …

Oxygen Delignification Kinetics And Selectivity Improvement, Steven M. Violette

Electronic Theses and Dissertations

Pulp strength loss during oxygen delignification is caused by cellulose chain cleavage resulting fiom attack by oxygen-based radicals generated through reactions with lignin. The objective of this research was to improve the lignin-to-cellulose selectivity during oxygen delignification by using radical-scavenging polymeric additives that adsorb on the cellulose surfaces where protection fiom radicals is needed. Among the polymers evaluated were starch, carboxymethyl-cellulose, galactomannan, xylan, and glucomannan. Oxygen delignification experiments were conducted on Northeast softwood Kraft pulps at different temperatures, sodium hydroxide charges, reaction times, and pretreatments. The effect of polymer additives on the selectivity and kinetics was studied. Polymer adsorption on …

Relationship Between Alkaline Pulp Yield And The Mass Fraction And Degree Of Polymerization Of Cellulose In Pulp, Mehmet Sefik Tunc

Electronic Theses and Dissertations

Wood as a raw material is generally the dominant cost factor for the production of chemical pulp. Therefore, an increase in pulp yield has a major impact on the competitiveness of a mill. In order to optimize pulp yield, for example by changing operating conditions, a mill must be able to monitor the yield accurately. However, an accurate "real-time" pulp yield measurement method is not available at the present time. Pulping yield is presently measured from the amount of pulp produced from a given quantity of wood consumed over a 3 to 6 month time frame. This method is obviously …

Surface Interactions Of Mercury On Gold Foil Electrodes In Electrodeposition And Stripping And ; An Investigation Of Free Thiolate Ions From Metal-Thiolate Chalcogenides, Charles Martin Watson

Electronic Theses and Dissertations

Mercury, a highly toxic metal, whose environmental concentration magnifies with ascension of the food chain, is monitored in our waters, food and air. Monitoring mercury is generally done by sample collection, transport to the laboratory; followed by: digestion of the sample, separation of the mercury and detection of the mercury: mostly by cold vapor atomic absorption or, cold vapor atomic fluorescence. These monitoring methods, preclude, routine, in-the-field mercury determination. New analytical techniques have been proposed for in the field determination of mercury. They consist of mercury adsorption onto a sensor or electrode and measuring how much is there either as …

Exciplex Tuning And Optical Memory Studies For Dicyanoargentate(1) And Dicyanoaurate(1) Ions Doped In Potassium Chloride Crystals Extension To Mixed Metal Gold And Silver Systems, Samanthika Ruvinie Hettiarachchi

Electronic Theses and Dissertations

Exciplex tuning and optical memory behavior of [Ag(CN)₂^-] and [Au(CN)₂^-] ions doped in KCl host crystals, pure KAg(CN)₂, and pure KAU(CN)₂ have been studied. Additionally, d¹⁰-d¹⁰ (KAu(CN)₂-KAg(CN))₂) and d¹⁰-d⁸ (KAu(CN)₂, KAg(CN)₂- K₂Pt(CN)₄) mixed metal systems have been synthesized and characterized. Several ultraviolet and visible emission bands are observed for [Ag(CN))₂^-] and [Au(CN)₂^-] ions doped in KC1 host crystals. Each emission band becomes dominant at a characteristic excitation …

Simulation Of Structure, Dynamics And Electron Diffraction Patterns Of Heterogeneous Clusters Armn2N, W. H. Jinasena

Electronic Theses and Dissertations

The nitrogen-argon system provides a useful paradigm for studying segregation and mixing behavior in heterogeneous clusters. Using three realistic pair potentials corresponding to argon-argon, nitrogen-nitrogen and argon-nitrogen interactions, the structures and thermodynamics of Ar_m(N₂)_n, clusters are investigated. Comparison of these results to previous simulation results on neat argon and nitrogen clusters is made. The initial focus of the study is the series of thirteen particle clusters of Ar_m(N₂)_13-m (0 ≤ m ≤ 13); molecular dynamics in the microcanonical ensemble is the principle simulation tool. The icosahedral nitrogen-argon clusters …

Stabilization Of Rutile-Related Thin Film On Tio2 Substrates, Youngnam Cho

Electronic Theses and Dissertations

Conducting metal oxide thin films are of broad interest because they have a wide variety of magnetic and electronic properties. Materials exist that range from superconducting to insulating, are ferromagnetic and are ferroelectric. These properties make thin conducting oxide films attractive for many industrial applications. A class of metal oxides exists that adapt the rutile crystal structure; the structure of the mineral rutile, TiO₂. These metal oxides have the general formula MO₂ where M is a metal cation of valence +4. Metal oxides crystallizing in the rutile structure also display a wide variety of physical properties. The …

A Study Of The Photodegredation Of Carbaryl: The Influence Of Natural Organic Matter And The Use Of Silver Zeolite Y As A Catalyst, Marsha Kanan

Electronic Theses and Dissertations

The photodegradation of carbaryl in the presence of Suwannee River natural organic matter (NOM) as well as the presence of AgY zeolites was studied. Two NOM samples were purchased in 2000 and 2001 and labeled as NOM-2000 and NOM-2001, respectively. The synchronous-scan luminescence spectra (SSLS) indicate the presence of different luminophores in the two samples. This suggests that although the compositions of the two NOM samples are similar, isomers composing the NOM mixtures are different. This difference was observed in the effect the two Suwannee River NOM samples had on the photodegradation of carbaryl. In particular, the photodecomposition of carbaryl …

Impact Of Preservative Treatments And Fungal Exposure On Phenolic Fiber Reinforced Polymer (Frp) Composite Material Utilized In Wood Reinforcement, Cihat Tascioglu

Electronic Theses and Dissertations

When wood products are exposed to environmental conditions conducive to biodeterioration, wood preservation becomes a necessity, especially when long-term utilization is desired. Although considerable literature exists on the treatment of laminated timbers and wood composites with wood preservatives, almost no information is available on the exposure of Fiber Reinforced Polymer (FRP) composites to wood preservative chemicals. In this work, FRP material was treated with common preservative chemicals and the effect of wood preservative treatments on mechanical properties of FRP material were investigated. Although the longitudinal elastic modulus was unaffected, some longitudinal strength losses were recorded for CCA and CDDC (water …

Effect Of Kraft Pulping On Oxygen Delignification, Haixuan Zou

Electronic Theses and Dissertations

The objective of the study reported here was to investigate experimentally the effect of the major Kraft pulping variables on the response of brownstock pulps to medium consistency oxygen delignification. Kraft pulping was performed on mixed Northeastern hardwood chips in a laboratory rocking digester. Kraft pulps of kappa number 16 and 20 mL KMnO₄ were produced by pulping under a variety of conditions. The effective alkali (EA) charged to the digester was varied over the range of 12 to 21% while the sodium sulfide content of the pulping liquor was varied between 0 to 30% sulfidity. Cooking temperatures of …

Synthesis Of Nano-Structured Monoclinic W03 Particles, Zhixiang Lu

Electronic Theses and Dissertations

The goal of this research is: 1) to develop synthetic methods for generating nanosized particles of monoclinic W0₃ (m-W0₃) and 2) to use the high surface area of the nano-sized material in infrared spectroscopic studies of the reactions of gaseous molecules with the particulate surface. Two methods of making nano-structured monoclinic tungsten trioxide (m-W0₃) particles are investigated. In one method, the sol formation occurs in the presence of a solution containing chelating agents and in a second approach, the sol formation occurs in a water-in oil emulsion. Commercial m-W0₃ particles are approximately 1 micron …

Photostabilization Of High-Yield Pulps Reaction Of Thiols And Quinones With Pulp, Jonathan Spender

Electronic Theses and Dissertations

Some thiols have been shown to be efficient in both bleaching and stabilizing the brightness of mechanical pulps. Two thiols, thioglycerol and glycol dimercaptoacetate, have received considerable attention due to their photostabilization effects. Their reactions with 1,4-benzoquinone, a model lignin compound, were investigated. In the first part of this study, reaction products were isolated using preparative HPLC and were fully characterized using GC-MS as well as ^l3C-NMR Both thiols were found to undergo Michael addition with the model quinone (in methanol) to yield a substituted hydroquinone. Further reaction with excess quinone in the presence of UVlight facilitated subsequent redox …

Synthesis And Reactivity Of Gold Thiolate Cluster Complexes, Hanan Abdou

Electronic Theses and Dissertations

Chemical oxidation of dinuclear gold(I) thiolates of the formula LLAu₂(SC₆H₄CH₃)₂ [LL= dppp, bis(dipheny1phosphine)propane and dppb, bis(dipheny1phosphine)butane] and dinuclear gold(I) thiolate complexes with bridging a propane dithiolate ligand of the formula LLAu₂(SC₃H₆S) [LL = dppp and dppb] was carried out using the mild oxidizing agent, ferrocenium, [Cp₂Fe]PF6). Spectroscopic studies and elemental analysis showed the formation of gold(I) clusters, disulfide, and ferrocene as products of this oxidation reaction. The clusters, [(dppp)AU₂(SC₆H₄CH₃)](PF₆) and [(dppb)Au₂(SC …

Grading The General Chemistry Laboratory: A Constructivist Approach., Barbara Stewart

Electronic Theses and Dissertations

Constructivist theories of learning posit that instructors cannot transfer their knowledge to students; students must actively construct their own understanding. The Inter-Chem-Net project uses technology and instrumentation to provide an individualized experience within the large general laboratory course, effectively establishing a constructivist methodology. A grading rubric was developed to communicate course expectations and provide an easy and reliable method of evaluating student work in the general chemistry laboratory. The grading rubric separates the learning outcomes into a checklist of skills associated with each particular grade. This checklist provides detailed feedback for individualized choices of experiments, a key component of the …

Redox Studies On The Anti-Rheumatoid Arthritis Gold Drugs: Auranofin And Solganol, Ahmed A. Mohamed

Electronic Theses and Dissertations

The oxidative behavior of Auranofin, 2,3,4,6-tetra-O-acetyl-1-thio-β-D-glucopyranosato-S(triethylphosphine)gold(I), was investigated by using cyclic voltammetry (CV) in 0.1 M Bu₄NBF₄/CH₂Cl₂ and 0.1 M Bu₄NPF₆/CH₂Cl₂ solutions using Pt working and auxiliary electrodes and a Ag/AgCl reference. CV studies at scan rates from 50-2,000mVs^-1 and Auranofin concentrations between 1 and 4mM, show two irreversible oxidation processes occurring at +1.1 V and +1.6 V vs. Ag/AgCl. Treatment of Auranofrn with the one electron oxidizing agent [Cp₂Fe]PF₆ gave a μ-thiolato digold cluster, [(Et₃PAu)₂(μ-SR)]₂^{2+ …}