Thesis (M.S.)--Rochester Institute of Technology, 2006. / Typescript. Includes bibliographical references (leaves 61-69).

Deinking flotation is an important part of the recycling process for used fibers, in which liberation is a key step in preparing the ink particles to be separated from fibers. The pigments of oil-based inks are hydrophobic and, therefore, can be readily separated from hydrophilic fibers by flotation, which is designed to selectively collect hydrophobic particles on the surface of air bubbles. On the other hand, the pigments in water-based inks are hydrophilic; therefore, they cannot be separated from fibers by flotation. Furthermore, the pigments in water-based inks are much smaller than those in oil-based inks and readily redeposit onto the fiber surfaces after they are liberated during the pulping process. Team members and I developed a novel method of measuring the degree of liberation of oil-based ink by ζ-potential measurement. The same method has been used to determine the degree of liberation of water-based ink. It has been found that adding a polyelectrolyte during the pulping stage greatly increases the liberation by increasing the disjoining pressure in the thin liquid film (TLF) of water confined between the pigment and fiber while at the same time preventing re-deposition. After the liberation, the pigments are then hydrophobized by adsorbing a surfactant on the surface to greatly improve flotation deinking. Finally, different types of flotation equipment were tested to identify the optimal flotation system to use in the deinking process. / Department of Energy grant DE-EE0007897, awarded to the REMADE Institute. / Master of Science / Paper recycling is a key way to participate in the circular economy. Part of the process of recycling paper is to remove any ink on the surface of the paper so that a clean white sheet of paper can be produced for additional uses. There are two types of ink commonly used for printing, oil-based and water-based. The latter seeing more and more adoption as climate goals continue to be a focus of society. One of the processes that is used in this process is deinking flotation, where the ink is separated from the fiber, attached to a bubble, floated to the surface, and separated from the fiber. The current work focuses on improving the ability to separate the ink from the fiber, improving the ability of the ink particle to attach to the bubble, and improving the equipment that is used for the separation. The work found that using common dispersants used in the mineral industry, novel reagents, and alternate equipment greatly increased the efficiency of the deinking process.

The purpose of this study is to compare Negro and white responses to the Rorschach.

Droplet formation in inkjet cartridges has been studied for several decades to improve print qualities. Currents and rigid nozzle plates are used inside the cartridge to fix the size of droplets exiting the chamber. This research is focused on studying the effect of nozzle flexibility on droplet formation. A flexible nozzle can be modeled as an flexible annular plate with a clamped outside edge. In this thesis, plate vibration equations are studied for an annular shape. An analytical solution is formed for the small deflection plate equation. To solve the large deflection plate vibration equation, Galerkin's method is used. Droplet formation is predicted by a one dimensional fluid dynamic model. An integrated plate vibration and droplet formation model is created with these basic building blocks. Results from simulation indicate flexible plates yield shorter droplet breakoff time and longer breakoff distance while generating a slightly droplet compared to a rigid nozzle. / Graduation date: 2004

Thesis (M.S.) in Chemical Engineering--University of Maine, 2002. / Includes vita. Bibliography: leaves 182-193.

Thesis (Ph. D.) in Chemical Engineering--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 141-149).

No description available.

No description available.

The magnetic particle inspection (MPI) method is a widely used non destructive testing (NDT) technique for ferrous structures. Magnetic inks used in MPI are suspensions of fine ferro/ferrimagnetic particles which, when applied to a magnetized test specimen, delineate surface flaws. This work is an investigation of some of the properties of magnetic ink systems and some aspects of their interaction with defect leakage flux. Reviews of magnetism, the MPI method and leakage flux at defects are given. The construction, characterization and automation of a 1.2 T electromagnet vibrating sample magnetometer, used for magnetic measurements on the inks, is described. The instrument has a resolution of better than l0(^-9) JT(^-1) . A 2D model of indication formation in MPI, based upon the simulation of many particles in the neighbourhood of a defect, is presented. Results of the role of several of the model parameters are given. Results indicate that carrier coefficients of viscosity at the lower end of the range investigated (η = 0.3 mPas) are optimum. The size and contrast of an indication increases with defect size. The contrast and rate of formation of contrast increase with defect aspect ratio. The effect of the contrast paint layer thickness indicates that the recommendation of the British Standard, BS 5044 (1973), is qualitatively correct. Experimental observations of particles in field gradients reveals a discrepancy between theoretical and observed behaviour which is attributed, in particular, to unobservable voids in the particles. Detailed characterization of the particles shows them to be aggregates of 20 - 200 nm crystallites which are probably single domain particles. The morphology of larger aggregates is related to measurements of the low field susceptibility. Evidence from intensive magnetic measurements supports the relationship between magnetic properties and aggregate characteristics. A 'In t' magnetic viscosity effect is reported. At 77 K, the coefficient of magnetic viscosity has a maximum near the coercivity field.

No description available.