Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 104-105). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 104-105). Also available on the Internet.

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Sujit Banerjee; Committee Co-Chair: Wm. James Frederick, Jr.; Committee Member: John D. Muzzy; Committee Member: Kristiina Iisa; Committee Member: Preet Singh. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Banerjee Sujit; Committee Member: Deng Yulin; Committee Member: Haynes Danny. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis--Auburn University, 2010. / Abstract. Includes bibliographic references (p.111-129).

The cost of pretreatment process for saccharification from biomass and the cost of dilute ethanol purification are significant components of the overall cost for fuel grade ethanol production through fermentation or other biological routes. This work focuses on developing optimal designs of dilute ethanol purification process and the new acid hydrolysis technology for the production of fermentable sugars from biomass where the overarching goal is to reduce the cost of ethanol production from biomass. In this thesis, the ethanol separation process with the reverse osmosis membrane pretreatment is developed to reduce separation cost and energy consumption especially when the feed is dilute. In addition, the new solid phase reactive separation system for biomass saccharification via acid hydrolysis is proposed. This new process is applied for both dilute and concentrated acid hydrolysis where the goal is to increase sugar yield and to reduce byproduct formation. The reaction kinetics of the concentrated acid hydrolysis is investigated through batch experiment. All of these use optimization approaches for seeking the best process designs and for parameter estimations.

The West Florida Shelf (WFS), typically characterized as being oligotrophic, is one of the most productive continental shelves in the United States. In addition to supporting a large fishing industry, the WFS also supports high biomass blooms of the toxic dinoflagellate Karenia brevis. Because of the large ecological and economic impacts these blooms have on the area, the ECOHAB: Florida program was developed to gain a better understanding of red tides and their initiation, maintenance, and dispersal. This interdisciplinary program consisted of monthly cruises from June 1998 through December 2001, with a hiatus from January through March of 2001. Hydrography, nutrients, chlorophyll a, phaeopigments, and a wide variety of other factors were measured during the cruises. In this paper chlorophyll a and phaeopigment concentration, nutrients, and hydrographic data were examined to explain the temporal and spatial distribution of chlorophyll on the shelf. Average surface chlorophyll values were 0.55 mg/m 3 with near bottom values averaging 0.85 mg/m 3. Chlorophyll was found to be highest near the estuaries of Tampa Bay and Charlotte Harbor with a decreasing gradient seaward. Near bottom chlorophyll values were generally two to fourfold greater than surface values. Midshelf stations (35- 50 m) were characterized by high near bottom chlorophyll, whereas the offshore stations (86-200 m) were characterized by a subsurface chlorophyll maximum ranging between 40 to 80 m deep. Nutrients were generally low across the shelf except for 1998 when a subsurface intrusion of nutrient rich slope water reached to the 20 m isobath. Temperatures ranged from 14.00 ° C to 31.47° C. Salinity ranged from 30.5 to 37.50 in the study area. Four blooms of Karenia brevis, lasting several months, contributed to the high chlorophyll concentrations along the inner shelf. Maximum chlorophyll concentrations of 27.10 mg/m 3 were a result of the October 1999 to March 2000 red tide. Blooms of Trichodesmium and diatoms also were contributors to patterns seen on the shelf. Maximum chlorophyll values were generally highest in the late summer and fall except for offshore values which showed little to no seasonality. Inshore of the 50 m isobath, average phaeopigments comprised from 43 to 68 percent of the measured Chl a, while offshore values were from 68 to over 100 percent. Inshore chlorophyll distributions were attributed to riverine and estuarine flux of nutrients, localized upwelling, and recycling of nutrients aided by salinity and temperature fronts. Midshelf distributions were attributed to the movement of biologically important material through the bottom Ekman layer from offshore to the inshore regions of the shelf. Offshore distributions were attributed to Loop Current upwelling and synoptic scale processes associated with seasonal meteorological forcing.

This report is a study on the smoldering combustion of natural sawdust from untreated woods. The objective was to develop and test an experimental technique to study the fundamental behavior of sawdust smolder. The experimental setup was an annulus cookstove packed with sawdust between the inner and outer radii creating a central hollow core. The sawdust was ignited by a heating coil wrapped around the inner radius. Thermocouples were embedded in the sawdust bed fanning out in the radial direction, and temperature was recorded throughout the smolder process. Consistent with the literature, the experimental results indicate that wood smolder consists of three pathways, 1) sawdust to char, 2) sawdust to volatiles, and 3) char to ash. Pathways 1 and 3 can be clearly characterized by the temperature profile of the smolder; however, pathway 2 often involves flaming of the sawdust and is beyond the scope of this study. Pathway 1, sawdust to char, is an endothermic reaction that results in a clearly defined char front that propagates across the sawdust bed in the radial direction. As smolder proceeds, the char continues to oxidize and breaks down into non-volatile products such as water vapor and carbon dioxide (CO₂) in further exothermic reactions. Pathway 2, char to ash, is an exothermic reaction that can lead to glowing combustion when exposed to sufficient amounts of oxygen and results in spikes in temperature. In contrast to the clearly defined char front, the ashing zone traces cracks in the sawdust where air can penetrate through, and has no discernible front. Section 1 discusses the motivation behind the study of sawdust cookstoves in third world countries, in particular Ghana, to replace wood with sawdust as a cheap alternative for household fuel. Section 2 details the experimental setup of the cookstove rig and the methodology of the experiments conducted. Section 3 reports the results of the experiments and analyzes the temperature profiles in relation to the three types of chemical reactions as noted above. Section 4 concludes with a summary of the results and discusses efforts in measuring emissions from the smolder and future work to be done. / text

The Earth's most extensive living space is found in the bathypelagic zone of the oceans, yet research in these areas is scant. The micronekton of the bathypelagic zone in the eastern Gulf of Mexico (EGOM) was investigated with the goals of comparing its community structure and trophic interactions with those of the well-studied overlying mesopelagic micronekton. Significant changes in faunal structure were found, including shifts in dominant families as well as species. Compared to the mesopelagic zone, the bathypelagic community had increased abundance and biomass contributions from the Gonostomatidae, Oplophoridae,and Eucopiidae, with a simultaneous decrease in the importance of the Myctophidae and the Dendrobranchiata. The changed faunal structure within the crustacean assemblage includes a distinct difference in reproductive strategies. There is increased prevalence of taxa which feature egg brooding and abbreviated larval development. In addition, the bathypelagic zon e was characterized by relatively large biomass contributions from rare but large species, particularly those within the families Oplophoridae and Nemichthyidae. The faunal shifts, in combination with a high percentage of bathypelagic species absent from mesopelagic samples (~50% of crustacean and ~37% of fish species), suggest the bathypelagic zone is home to a distinct pelagic community, with a biology and ecology fundamentally different from that of the mesopelagic zone. The broad zoogeographic distributions of bathypelagic species suggest the EGOM assemblage is possibly similar to that of other geographic locations at similar latitudes. Diet analysis was performed on several prominent species and revealed 2 major feeding strategies based on diet composition and prey size. Species of Cyclothone and Eucopia preyedon small planktonic crustaceans, while the decapods examined were primarily piscivorous. The fraction of fish in the diets of decapods was greater than in their mesopelagic counterparts. It is suggested the primary trophic players in the system are oplophorid shrimps, followed by Cyclothone spp.

The second generation bioenergy crops Miscanthus x giganteus and short rotation coppice (SRC) willow are the two main bioenergy crops in the UK and have become an integral part of legislation to provide an alternative to fossil fuels and to reduce national greenhouse gas (GHG) emissions. To reach emission targets, it is estimated that approximately 350,000 ha of land could be made available for bioenergy crops by 2020. Despite the promise of these crops, there have been very few field-studies regarding soil GHG (CO2, CH4 and N2O) emissions and many of the published studies are life cycle analyses or modelled fluxes from soils using default values from the IPCC. The first aim of this research was to quantify the in situ soil GHG budget and to establish the drivers of these GHG fluxes for Miscanthus and SRC willow. The second aim of this research was to provide a more in-depth understanding of C cycling under Miscanthus i.e. litter and roots through two field experiments. Overall, the results from this work confirm minimal emissions of CH4 and N2O from soil under Miscanthus and SRC willow. CO2 flux was found to be the major efflux from soils and it was found in Miscanthus, that the majority of this flux was derived from below ground respiration. Litter played an important part in providing nutrients to the soil, which is vital in systems that are not fertilised. Litter also contributed to SOM accumulation on the soil surface and may promote long-term C sequestration. The results from this work combined with other literature would suggest that these second generation crops offer advantages to first generation crops, but more field-based studies are required to say if they can offer the large-scale GHG savings needed to be a viable alternative to fossil fuels.