2923 research outputs found
Sort by
Lignin Ethanolysis Depolymerization and Product Upgrading with Mesoporous and Palladium Supported Zeolite Catalysts
Get PDFLignin is a high-volume farm waste and environmental hazard of paper and pulp industries. To promote the utilization of its rich aromatic units into important chemicals and fuels, efforts were intensively made to breakdown lignin structure with a variety of depolymerization processes involving heating, solvent, and catalysts or their combination. Among those processes, ethanolysis in supercritical conditions shows promising performance for its high lignin conversion and little char formation. To improve the yield and selectivity of aromatics, particularly phenols, we examined the important roles of acidity and pore structure of different zeolite catalyst play in this process. Zeolites with close micropores and acidity defined by their crystal structures including Beta, Y, and ZSM-5 were first examined. Zeolites with the same microporous structure but different acidic strength caused by various H-type sites were further evaluated. Comparisons were further made between HZSM-5 and HY zeolites with unique mesoporous structures and their counterparts with exclusive micropores. Despite the complexity of lignin depolymerization and its greatly diversified products, strong acidity was found effective to cleave both the C-O-C and C-C linkages on lignin structure to receive more phenols while mild acidity works mainly in ether bond breakdown. When the diffusion issues of gigantic lignin intermediate and monomer products are severe (e.g., in microporous zeolites), overall yield and selectivity of lignin depolymerization products fall and the pore size of catalyst becomes dominant between the two key factors. Like in many petrochemical reactions involving bulky molecules, hierarchical pore structure also is important to promote mass transport and increase the exposure and utilization of acidic site inside zeolite catalysts. At the presence of mesopores in zeolites, their pore configuration is less sensitive when comparing with the acidity to decide the yield and selectivity to phenols of C8-C11. These findings provide important guidelines on the selection and design of zeolites with appropriate acidity and pore structure to facilitate lignin depolymerization or other cracking processes.
The products of lignin depolymerization are a mixture of various organic compounds including alcohols, ester, phenols, and other large hydrocarbons with high oxygen content (up to 40 wt.%), poor thermal stability, and low heating values (16-19 mJ/kg), insuitable to serve as alternative or replacement to fossil fuel. Hydrotreating step, a classic refinery process to remove oxygen and other unwanted elements in oil by adding hydrogen, is often suggested for the upgrading of bio-oil to increase its C/O ratio, improve its energy density, stability, as well as other required fuel properties. We successfully synthesized new mesoporous zeolites, Meso-ZSM-5, via solid-state crystallization of dry aluminosilicate nanogels. Palladium was further loaded on these zeolites to form a bi-functional catalyst (Pd/Meso-ZSM-5). When used in the hydrodeoxygenation of guaiacol, a major lignin depolymerization compound, Pd/Meso ZSM-5 exhibits superior guaiacol conversion and product distribution when compared with those supported on conventional microporous ZSM-5 counterparts. This is attributed to the improved diffusion and accessibility of active sites inside Meso-ZSM-5 with its unique hierarchically porous structure formed through neighbor nanocrystals connecting at edges. Ring saturated hydrocarbons are largely produced at 200 °C when hydrogenation dominates while alkaylated aromatics become major HDO products as deoxygenation becomes favorable at 250 °C. Unlike the disappointing conversion and severe coking issue over many HDO catalysts, this catalyst shows excellent anti-coking performance at various temperature conditions. These encouraging results demonstrated the great potential of Pd/Meso-ZSM-5 catalyst in bio-oil upgrading processes and may ignite the wide use in emerging renewable energy fields as well as many other reactions in traditional fossil fuel industrials
The Role of Extrinsic Motivators on Job Satisfaction and Turnover in Higher Education Within R2 Research Universities in the United States
Get PDFThe purpose of this study was to evaluate extrinsic motivators and the relationship they have with job satisfaction and turnover intent. Literature suggests that higher education faculty have differing needs and satisfiers than other public sector employees (Lee & Wilkins, 2011; Maidani, 1991). As a result, the Delphi method was utilized to identify extrinsic motivators that were tailored to higher education. Once these motivators were identified through a panel of experts, they were combined to create a survey with previously established scales measuring job satisfaction and turnover intent.
This survey was designed to answer the following research questions: 1) what relationship, if any, exists between extrinsic motivators and job satisfaction? 2) what relationship, if any, exists between extrinsic motivators and turnover intent? And 3) what extrinsic motivator differences, if any, exist between colleges? A factor analysis was performed on the survey to identify correlated items and group them into factors. As a result, five factors were derived from the survey, job satisfaction, relationships, finances, autonomy, and work environment conditions. After performing multiple regressions using the identified factors and the dependent variables, job satisfaction, and turnover intent, it was found that job satisfaction and the importance of relationships were predictors of both dependent variables. Work environment conditions were found to be a predictor of job satisfaction, and there were no significant differences in extrinsic motivators between colleges
A Tutorial of the Immersed Interface Method
Get PDFThe immersed interface method is a computational methodology to solve differential equations with non-smooth solutions across interfaces. In this talk, Dr. Xu will use a simple example to demonstrate the main ingredients and features of this method. He will then present the application of the method to the simulation of fluid flows and make the connection of the application with the simple example.
This talk is a tutorial of the method for undergraduate students.
Come at 3:30pm for refreshments, speaker at 4:00p
The Influential Women of Richard II
No full textThis paper was written for English 415 after we read The Tragedy of Richard II . My goal was to inform my audience about the women characters in the play. I determined that they were not a normal reflection of 16th century European women. I conducted research to validate my points, and to determine what the reason behind Shakespeare\u27s portrayal of these women
Evaluation of Compression and Flexure Properties of Different Geopolymer Mixes
No full textRecent studies of heat-cured fly-ash-based geopolymer concrete (GPC) have shown its suitability for the fabrication of new precast structural members and improved structural health of existing infrastructure components using spot repair. However, GPC curing requires continuous moderate heating (145°F) for 5 to 18 hours, and thus, an oven or a heat source is essential for curing. Curing large structures requires large amounts of energy, which can offset the environmental benefits of using GPC. The frontal polymerization (FP) technique has the potential to remove this heat source from the equation and can enhance the curing of ultra-high strength fly-ash-based inorganic GPC that is embedded with organic polymer composites. Initiation of the curing process requires a one-time short-period localized heating. However, conducting FP on geopolymer concrete materials requires full evaluation of mechanical properties of different geopolymer mixes. The present study will focus on the evaluation of compression and flexure properties of different geopolymer mixes with a goal to lay the foundation for achieving frontally polymerized geopolymer concrete (FPGPC) materials
Student Stage Manager
No full textThe 2019 School of Theatre production Begets: Fall of a High School Ronin was a complex and challenging production both onstage and off. In my role as Production Stage Manager it was my duty to organize and run the production from start to finish. In this project I will share the organizational strategies and paperwork I used to ensure the artistic integrity designed by the creative team, and maintain a safe environment for everyone involved in the production. Communication is paramount to my work as Production Stage Manager. I will showcase the complex and fundamental paperwork I generated for this production and discuss the importance and need of its use for a live performance event. I will further discuss the safety issues involved with my work as Production Stage Manager and provide examples from my paperwork of moments where my organizational strategies and paperwork prevented show malfunction or injury to student performers
Exposing Evil: My Lai, the Media, and American Atrocities in Asia, 1941-1975
Get PDFIn both the Pacific War against Japan from 1941 to 1945 and the Korean War from 1950 to 1953, United States combat troops—emboldened by a combat culture of dehumanization through racism and a military that enacted policies of attrition— committed atrocities against Asian soldiers and civilians. This trend continued into the Vietnam War unabated beginning in 1965. Incidents of atrocities committed by American troops overseas were not publicly discussed until the My Lai Massacre of 1968 was revealed to the American people in 1969. Once the massacre became a national news story published in outlets all over the country, American citizens were forced to confront the reality of what some US combat troops had done in Asian wars for decades.
This thesis argues that the media coverage of the My Lai Massacre broke a culture of silence, a phenomenon previously observed in military circles, that existed in American society concerning atrocities committed by GIs in American wars in Asia during the mid-twentieth century. Myths of American righteousness abroad and the morally good GI were challenged by liberal doves who reconciled the reality of My Lai with their national identity and called for a collective acceptance of responsibility by Americans. In contrast, a large contingent of war hawks, unwilling to let the overarching myth of American exceptionalism fade, defended and incorporated American war atrocities into those ideas. War atrocities and the myth of American exceptionalism persist in the wake of My Lai, but the culture of silence has diminished as Americans continue to reconcile atrocities with their wars
Flexure Strength Enhancement Study in Geopolymer Mortar
Get PDFThis thesis includes the structural enhancement study on the flexible or semi-rigid design of geopolymer mortar (GPM) to address tensile cracking commonly found at the invert of reinforced concrete pipes. Concrete pipes are often subjected to harsh sewer conditions, which eventually spread to the reinforcement skeleton through the resulting cracks and corrode it to cause premature structural failure of the pipe. Therefore, this added flexibility to the pipes’ rigid material will not only serve to limit corrosion of the steel reinforcement within the pipes but will also aid in increasing the structural stability of the pipe in its entirety. The suggested material for this semi-rigid design is additionally beneficial due to its use of recycled ingredients. Class F fly ash accounts for most of the material’s mass while fibers (steel, polyvinyl alcohol ‘PVA,’ and nylon) are used for their contributions to the geopolymer mortar’s overall flexibility. An alkali solution (sodium hydroxide, NaOH and sodium silicate, Na2SiO3) defines the mixture’s aqueous solution. These inexpensive and mostly recycled materials can directly reduce costs for the piping industry while also reducing emissions caused by the creation of the clinker used in Portland Cement Concrete. By improving overall concrete pipe stability and tensile strength, prolonging the life cycles of steel reinforcement and using recyclable waste materials as base ingredients, the research outcome for semi-rigid pipes made by flexible GPM supports a financially and environmentally green shift in the future of pipe networking
The Role of Notch in Adipose-Derived Stem Cell Adipogenesis
Get PDFObesity is the leading cause of chronic disease and has contributed to significant health problems and complications. In order to solve this increasingly serious social problem, it is particularly important to deepen the understanding of the biological causes of obesity. Obesity is the result of an increased mass of adipose tissue after excessive caloric intake, and adipogenesis is the main strategy through which the body increases the number of adipocytes. However, due to the lack of research, the current understanding of adipogenesis is not enough to yield results in the clinic.
The regulation of adipogenesis is complex, and the role of the Notch signaling pathway in adipogenesis has long been controversial, as the role of individual Notch receptors appears to vary with experimental conditions. In this dissertation, we demonstrate that in human adipose-derived stem/stromal cells (hADSCs), Notch1 and Notch3 have distinct expression profiles and roles during adipogenesis. Expression of these Notch receptors changed during adipogenesis with Notch3 expressed prior to the formation of lipid vesicles and Notch1 only appearing after vesicle formation. In addition, the siRNA-mediated Notch3 knockdown demonstrated an increased expression of PPARγ, an adipogenic marker, which was paralleled by a marked decrease in expression of β-catenin, the key functional component of the canonical Wnt/β-catenin signaling pathway. This study deepens the understanding of Notch signaling by clarifying the distinct roles of Notch1 and Notch3 during adipogenesis offering a novel therapeutic target for research aimed at obesity and diabetes
Money and Power: The Effects of the Gender Wage Gap on Women in State Legislatures
No full textCountless factors play into an individual’s decision to run for public office. This is true of everyone regardless of gender, but it seems especially true of women. Women in the United States have undeniable pressures keeping them out of the public sphere. In this research paper, I propose that the primary obstacle women face in their potential political candidacy is the gender wage gap. I test this hypothesis using OLS regression on a time-series cross sectional model with data collected from the US Census Bureau and the National Conference of State Legislatures. I compare the relationship between the gender wage gap in each state and the percentages of women in state legislatures from 2010 to 2017. My control variables are the ratios of women in state populations and the level of partisanship in each state. My results suggest that my hypothesis is supported at the 99.9% confidence level, and that the gender wage gap does greatly influence the number of women in state legislatures. That is, as states come closer to gender wage parity, they see higher rates of women in their legislatures and vice versa. These findings emphasize the importance of female representation in the public and economic spheres and expand the range of the extant literature, which is particularly sparse on the relationships between these variables