Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 168-175).

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: James W. McGinity. Vita. Includes bibliographical references.

Thesis (Ph.D. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 123-128).

Melt inclusions record valuable information about pre-eruptive melt volatile concentrations. However, a vapor bubble commonly forms in inclusions after trapping, and this decreases the dissolved CO2 concentration in the trapped melt. To quantify CO2 loss to bubbles, Raman spectroscopic analysis was used to determine the densities of CO2 vapor in the bubbles. The samples analyzed in this study are from two Cascade cinder cones near Mt. Lassen and two Mexican cinder cones (Jorullo, Paricutin). Using analyses of dissolved CO2 and H2O in the glass in the inclusions, the measured CO2 vapor densities were used to reconstruct the original dissolved CO2 contents of the melt inclusions at the time of trapping. The Raman-restored CO2 values are similar to restored CO2 values calculated using a model of cooling and olivine crystallization in the trapped melts. This thesis includes unpublished co-authored material.

No description available.

The amount of volatile elements dissolved in silicate melts is a controlling factor in a range of geologic processes, which include hazardous volcanic eruptions, economically-significant ore-forming systems, and global-scale volatile fluxes, which contribute to planetary evolution. While melt volatile contents are important, estimating the origin and fate of volatiles distributed within magmas is challenging because volatiles exsolve from the melt during eruption and are transferred into the atmosphere. Therefore, the stratigraphic record of volcanic and intrusive deposits does not contain direct information regarding the pre-eruptive volatile content of the melt. However, melt inclusions trapped within growing phenocrysts present an opportunity to sample the melt before it has completely degassed. Analysis of melt inclusions is challenging owing to a range of processes which occur after the melt inclusion is trapped and which overprint the original texture and composition of the inclusion at the time of entrapment. Thus, efforts to accurately determine the current composition of the melt inclusion sample and then infer the original composition of the trapped melt which that inclusion represents require a combination of microanalytical, numerical, and/or experimental methods. In Chapter 1, we present a pedagogical approach for estimating the processes that affect the CO2 content of a magma from its origin during melting a C-bearing source material to its exsolution into a free fluid phase during crystallization and degassing. In Chapter 2, we explore different experimental, microanalytical, and numerical methods which may be used to estimate the CO2 contents of melt inclusions that contain fluid bubbles and describe the advantages and disadvantages of each approach. In Chapter 3, we apply some of the methods discussed in the previous chapters to estimate the pre-eruptive volatile content of Haleakala Volcano (Maui) and assess different melting mechanisms that may be active in the Hawaiian plume. / Doctor of Philosophy / Volcanoes are features which form on the Earth’s surface and are located above regions where material melts tens of kilometers (or more) below the surface. The process of melting is studied through laboratory experimentation, and therefore it is possible to estimate the composition of deep subsurface material based on the compositions of volcanic rocks which can be sampled on the Earth's surface. This sub-discipline of geologic research is called "igneous petrology." A fundamental problem in igneous petrology is estimating the volatile content of the Earth's deep interior. Volatile elements are those elements such as hydrogen and carbon, which are stable as gasses in the atmosphere rather than in the mineral components of a rock. It is thought that the gasses produced from volcanic vents, of which the compositions are well known, represent volatile elements which were originally present as dissolved components in the melt. Experiments performed on volcanic rocks have demonstrated that volatile elements can be dissolved in melts at high pressures corresponding to depths within the Earth's crust, and these elements exsolve from the melt when it approaches the surface -- similar to how CO2 can be dissolved in a carbonated beverage, which bubbles out when the beverage is opened. The only geologically-persistent features which preserves the pre-eruptive volatile content of a melt (i.e. how much gas was dissolved before eruption) are droplets of melt which are accidentally trapped within crystals that grow from the melt as it cools near the Earth's surface -- these are called "melt inclusions." While melt inclusions are useful in this regard, they are challenging to apply to geologic problems because they undergo a range of physical and chemical changes after they are trapped, which can alter their composition from the original composition of the melt that was trapped. This dissertation concerns the theory used to infer how volatile elements are distributed within the deep Earth, analytical and numerical methods used to gather relevant information from melt inclusion samples, and an application of these methods to investigate the volatile content of the mantle below Hawaii. Chapter 1 describes a framework for systematically determining the amount of CO2 distrubuted within a given volcanic setting. Chapter 2 compares different methods used to estimate the original volatile content of melt inclusions from Kamchatka, which have formed fluid bubbles -- a common feature present in melt inclusions. Chapter 3 applies the methods described in the first two chapters to estimate how volatile elements are distributed within the Earth's mantle below Hawaii, and how the process of melting transfers them to the Earth's atmosphere.

No / A novel, green, and continuous method for solid-state polymorphic transformation of artemisinin by high temperature extrusion has recently been demonstrated. This communication describes attempts to understand the mechanisms causing phase transformation during the extrusion process. Polymorphic transformation was investigated using hot stage microscopy and a model shear cell. At high temperature, phase transformation from orthorhombic to the triclinic crystals was observed through a vapor phase. Under mechanical stress, the crystalline structure was disrupted continuously, exposing new surfaces and accelerating the transformation process.

Traditionally ultrafine fibers below 1 dpf are produced by extrusion followed by mechanical drawing. A modified melt spinning apparatus with high-speed air nozzle was designed and fabricated to produce continuous polypropylene filaments by cold air drawing only. With this setup, the fiber is quenched and simultaneously attenuated by a symmetric cold air jet. Since the formation of fiber structure is highly dependent on the processing conditions, the new process will provide a unique operation window to study fiber attenuation and structural formation under high-speed cold air drawing. Based on computational fluid dynamics simulation results, a parametric study was carried out under different process conditions which include processing temperature, air velocity and polymer volume flow rate. Effects of changes in processing variables on the fiber diameter, molecular orientation, crystallinity, tensile strength and other properties were studied. Furthermore, a theoretical model was developed to analyze the non-isothermal fiber attenuation mechanisms. The new knowledge obtained in this study would likely yield a new process for producing innovative fiber products.

Skim, sweet buttermilk, and butter derived aqueous phase components were used to re-emulsify low-melt and medium-melt fraction butteroils to yield 20% milkfat creams. The implications of separation temperature in obtaining components, melting point characteristics, and formulation on the chemical and physical properties of reformulated and natural creams were analyzed. Transmission electron microscopy indicated that both reformulated and natural creams were oil-in-water emulsions, demonstrating lipid globules surrounded by surface material. Chemical analysis of components proved that sweet buttermilk and butter-derived aqueous phase components had significantly higher (p less than or equal to 0.01) amounts of cholesterol and phospholipid than skim milk, resulting in creams formulated with sweet buttermilk and butter-derived aqueous phase creams having significantly higher (p less than or equal to 0.01) amounts of cholesterol and phospholipid than creams formulated with skim milk. Butter-derived aqueous phase had higher (p less than or equal to 0.01) amounts of lipid, cholesterol, and phospholipid than sweet buttermilk. However, skim component had higher (p less than or equal to 0.01) amounts of protein than butter-derived aqueous phase. When compared to natural creams, creams consisting of sweet buttermilk and butter-derived aqueous phase components had similar amounts of total phospholipid and amount of phospholipid adsorbed to lipid globules than creams consisting of skim component. Creams consisting of skim component had higher (p less than or equal to 0.01) amounts of protein than natural cream. Reformulated creams having low-melt fraction butteroil had higher (p less than or equal to 0.01) amounts of cholesterol. For reformulated creams, creams processed from components obtained by 49oC separation had significantly higher (p less than or equal to 0.01) amounts of cholesterol than like creams manufactured from 55oC separation components. Creaming stability, viscosity, feathering, and sensory quality of reformulated and natural creams were analyzed over a 13 day storage period at 3.3oC. Formulation, separation temperature, or melting point characteristics did not significantly (p greater than 0.01) affect creaming stability of reformulated and control creams homogenized at 13.6/3.4 MPa. The day within storage period, however, was a significant factor (p less than or equal to 0.01) in determining creaming stability of reformulated and natural creams. All creams displayed typical non-Newtonian behavior at 7oC, displayed by hysteresis curves in which viscosity decreased as shear rate increased. Formulation and separation temperature used to obtain components did not have a significant (p greater than 0.01) effect on viscosity; however, all creams formulated with medium-melt fraction butteroil had significantly (p less than or equal to 0.01) higher apparent viscosity values than creams with low-melt fraction butteroil at shear rate 692.48 s-1 and at 1384.96 s-1 and 2769.92 s-1 for creams formulated with skim component. Regardless of formulation, separation temperature, and melting point characteristics, all creams feathered in a pH range of 4.70-5.09. Reformulated and natural creams met sensory quality specifications as determined by the In/Out Method of Specification, except for creams formulated with skim milk and low-melt fraction butteroil which were characterized as having oxidized flavors. Creams formulated with buttermilk and butter derived aqueous phase had more comparable physical properties to natural creams than skim milk creams. / Master of Science

No description available.