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

Engineering Commons™

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

Theses/Dissertations

2001

Electronic Theses and Dissertations

Articles 1 - 15 of 15

Full-Text Articles in Engineering

A Molecular Investigation Of Absorption Onto Mineral Pigments, Brian J. Ninness Dec 2001

A Molecular Investigation Of Absorption Onto Mineral Pigments, Brian J. Ninness

Electronic Theses and Dissertations

Pigment suspensions are important in several processes such as ceramics, paints, inks, and coatings. In the wet state, pigments are combined with a variety of chemical species such as polymers, surfactants, and polyelectrolytes which produce a complex colloidal system. The adsorption, desorption, and redistribution of these species at the pigment - aqueous solution interface can have an impact on the behavior in both the wet state or its final dried state. The goal of this work is to establish a molecular picture of the adsorption properties of these pigmented systems. A novel in situ infrared technique has been developed which …

Go to article

The Relationship Between Rheology, Application Method, And Final Coating Structure, Basant Galal Dimetry Dec 2001

The Relationship Between Rheology, Application Method, And Final Coating Structure, Basant Galal Dimetry

Electronic Theses and Dissertations

Paper is coated to improve the printability and the visual properties. The factors that determine the coating structure are important because the structure determines the physical, optical, and printing properties. This work focuses on determining a relationship between the rheological properties of the coating, the application method, and the final coating structure. Coatings with different polymers and pigments were characterized in terms of steady shear and viscoelastic properties. These coatings were applied onto plastic film and paper with a laboratory rod coater, a spray coater, and a high-speed blade coater. The final coating structure after drying was characterized in terms …

Go to article

Characterization Of Chitosan Films For Cell Culture Applications, Michael Katalinich Dec 2001

Characterization Of Chitosan Films For Cell Culture Applications, Michael Katalinich

Electronic Theses and Dissertations

Chitosan (β-(l,4)-2-amino-2-deoxy-D-glucose) is a naturally occurring, abundant biopolymer exhibiting desirable biomaterial properties of biodegradability, low toxicity and good biocompatibility. These properties indicate the suitability of chitosan as a surface for mammalian cell growth. The goal of this thesis is to explore the potential for using chitosan as a surface for NIH 3T3 fibroblast attachment and growth. '4 standard, reproducible film-formation technique, based on other researchers techniques was established. The reproducibility of this technique. through characterization of the physical and chemical properties of these films, was good. The attachment and growth of NIH 3T3 fibroblasts on chitosan films and controls was …

Go to article

The Influence Of Fiber Swelling On Paper Wetting, Sedef Akinli-Kocak Aug 2001

The Influence Of Fiber Swelling On Paper Wetting, Sedef Akinli-Kocak

Electronic Theses and Dissertations

The water uptake behavior of fibers, especially those at the surface of paper, influences printing and coating operations. The dynamic water uptake behavior of the surface fibers may determine the initial consolidation of the coating at the surface and the penetration of coating into the paper, but clear studies on this topic have not been reported in the literature. Four different fiber types and seven different paper sheets were investigated in the present study. The three different fiber types were prepared by carboxymethylation of softwood kraft pulp thereby producing pulps with different water uptake values. The fiber length and water …

Go to article

Influence Of Viscoelasticity On The Nano-Micromechanical Behavior Of Latex Films And Pigmented Coatings, Manish Giri Aug 2001

Influence Of Viscoelasticity On The Nano-Micromechanical Behavior Of Latex Films And Pigmented Coatings, Manish Giri

Electronic Theses and Dissertations

Nan0 to microscale deformation behavior of different carboxylated styrene-butadiene co- polymer Latexes were investigated using a commercial nanoindentation device. The latexes dif- fered primarily in their glass transition temperature (Tg). The bulk dynamic rheological properties, as determined from a rheometer, dictate the axismmetric deformation behavior of the latexes. Results from dynamic tests performed on latexes were analyzed using the theories in contact and fracture mechanics. Two theories of linear viscoelastic fracture mechanics (LVEFM) were employed to model the adhesion hysteresis (loading-unloading cycle) curves to obtain meaningful cohesive zone (fracture process zone) parameters and a stress intensity functional ( …

Go to article

Bubble Growth Behavior In Supersaturated Liquid Solutions, David Robert Cyr May 2001

Bubble Growth Behavior In Supersaturated Liquid Solutions, David Robert Cyr

Electronic Theses and Dissertations

The growth characteristics of gas bubbles in supersaturated liquid solutions were measured in preliminary experiments involving glass bottles followed by more controlled and systematic investigations using a custom designed experimental apparatus. It was proven that the presence of pre-existing gas was responsible for the bubble formation observed. Bubble growth occurred in very regular cyclical patterns at specific locations containing trapped gases. In the custom designed apparatus, liquids could be saturated with gases and supersaturated solutions made by depressurizing the system. Artificial capillaries, pre-seeded with air bubbles, behaved in a similar manner to naturally occurring sites containing pre-existing gases. The apparent …

Go to article

Gloss Dynamics Of Inkjet Printers, Amol G. Shirke May 2001

Gloss Dynamics Of Inkjet Printers, Amol G. Shirke

Electronic Theses and Dissertations

Inkjet printing is a popular non-impact technology with widespread use in home and office applications. The basic principle involves propelling ink drops of different colors on a substrate. High quality images, near photographic quality, are now possible. The gloss of the printed substrate is an important quality attribute. Printed gloss depends on a number of characteristics of the media and the ink, but a good fundamental understanding is not available in the literature. The dependence of the gloss on the media and ink characteristics is reported in this work. The experimental results are compared with values predicted by a mathematical …

Go to article

Micro-Probe For Physical And Chemical Surface Analysis, Joshua Mathews May 2001

Micro-Probe For Physical And Chemical Surface Analysis, Joshua Mathews

Electronic Theses and Dissertations

Non-uniform porosity of paper and coated paper is important in printing and paper making industries. Current porosity measurements give results averaged over a large area. A new method is developed to determine local variations in porosity and surface chemistry. A measured volume of a probe liquid is applied to a hemispherical glass probe. The substrate of interest is brought into contact with the fluid drop. The resulting liquid bridge exerts a force on the probe due to surface tension forces. A video camera is used to visually correlate the physical phenomena with the force-time data. The force-time data is recorded …

Go to article

The Influence Of Process Parameters On Filament Size Distribution, Saybil Nuray Ercan May 2001

The Influence Of Process Parameters On Filament Size Distribution, Saybil Nuray Ercan

Electronic Theses and Dissertations

Filaments are formed at the exit of rolling nips in some coating and printing operations. The filament size distribution can determine product quality such as gloss. The average filament size is linked to operational difficulties such as misting. The filament size distribution of various fluids and inks is characterized and compared to theoretical model. A high-speed video camera is used to visualize the exit of a rolling nip. The size distribution of the filaments is characterized with image analysis. A laboratory print tester is used with the high speed camera to characterize the size of the defects right after printing. …

Go to article

Artificial Recharge Of Groundwater As A Water Management Option For Eastern Maine, Robert J. Saunders May 2001

Artificial Recharge Of Groundwater As A Water Management Option For Eastern Maine, Robert J. Saunders

Electronic Theses and Dissertations

The declining population of Atlantic salmon in eastern Maine has brought the wild blueberry industry's irrigation practice of pumping water directly from ponds and streams under scrutiny. Restrictions on pumping from streams has prompted the industry to seek new water resources. One resource with potential to assist the industry to meet its irrigation needs is groundwater. However, preliminary research has shown that groundwater is not capable of completely satisfying irrigation needs. To evaluate the potential that artificially recharging the groundwater during spring run-off to retain the water for later use as irrigation, the groundwater software Visual MODFLOW was applied. Inputs …

Go to article

Gene Expression Data Analysis Using Fuzzy Logic, Robert Reynolds Jan 2001

Gene Expression Data Analysis Using Fuzzy Logic, Robert Reynolds

Electronic Theses and Dissertations

DNA microarray technology allows for the parallel analysis of the expression of genes in an organism. The wealth of spatio-temporal data provided by the technology allows us to attempt to reverse engineer the genetic network. Fuzzy logic has been proposed as a method of analyzing the relationships between genes as well as their corresponding proteins. Combinations of genes are entered into a fuzzy model of gene interaction and evaluated on the basis of how well the combination fits the model. Those combinations of genes that fit the model are likely to be related. However, current analysis algorithms are slow and …

Go to article

Optimization Of A Multi-Aixs Electro-Mechanical Scanning System., Raul Urbina Jan 2001

Optimization Of A Multi-Aixs Electro-Mechanical Scanning System., Raul Urbina

Electronic Theses and Dissertations

This thesis presents efforts to enhance the system performance of an ultrasonic scanning machine. New developments in electronics are used to enhance the system performance. This work focuses on optimizing the system repeatability with a robust triggering system for the scanner. The robust triggering system applies new advances in programmable logic devices that make the replacement of complicated digital circuits possible. Modeling of wave propagation through anisotropic media is used to increase the system dynamic range. The model-based gain control compensates for variations in thickness and materials by controlling the excitation pulse amplitude. The automatic gain is implemented using integrated …

Go to article

The Flexural Response Of Bolted Composite Panels At Elevated Temperature, Christopher Gary Malm Jan 2001

The Flexural Response Of Bolted Composite Panels At Elevated Temperature, Christopher Gary Malm

Electronic Theses and Dissertations

Carbon fiberlcyanate ester matrix composite panels with bolted connections to aluminum endplates were tested in four point bending at room and elevated temperatures. The specimens tested were subcomponents of the NASA X-38 Crew Return Vehicle. The X-38 is the proposed escape vehicle for the International Space Station, currently being constructed in Earth orbit. During reentry into the Earth's atmosphere, the composite aeroshell of the X-38 is expected to experience elevated temperatures, which makes accurate characterization of material properties at elevated temperature imperative to a sound design. Three varieties of specimens were tested: flat composite laminates, hat-stiffened composite laminates, and sandwich …

Go to article

The Development Of A New Anemometer For Measuring High Speed Winds On Mount Washington, New Hampshire, Mark W. Thoren Jan 2001

The Development Of A New Anemometer For Measuring High Speed Winds On Mount Washington, New Hampshire, Mark W. Thoren

Electronic Theses and Dissertations

Mount Washington, NH is well known as the "Home of the Worlds Worst Weather." Winds on the mountain regularly exceed 100 miles per hour, the record being 231 mph on April 12, 1934. There is a long history of weather observation on the mountain that has included various recording techniques. Until recently, the primary means of recording data has been paper strip charts. This project represents significant improvements to the Observatory's instrumentation system. Measuring windspeed on Mount Washington presents a number of design challenges. Any instruments directly exposed to the weather must be very durable. Fortunately this problem had been …

Go to article

Current Voltage Characteristics Of A Semiconductor Metal Oxide Sensor., Huilin Ren Jan 2001

Current Voltage Characteristics Of A Semiconductor Metal Oxide Sensor., Huilin Ren

Electronic Theses and Dissertations

The current versus voltage (IN) characteristics of undoped and gold doped W03 thin film sensors were studied both experimentally and theoretically. A simplified equivalent circuit was formulated for the W03 sensor. It includes forward and reverse biased Schottky diodes which represent the contact region between the electrodes and the film and a resistor which represent the sum of crystallite resistance and the intercrystallite resistance between the individual crystallites. According to the electron transport mechanisms through the Metal Semiconductor (MIS) boundaries and intercrystallite boundaries, two kinds of yV and corresponding ResistanceNoltage(RN)characteristics are possible, one based on thermionic emission theory and the …

Go to article