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The purpose of this non-experimental, quantitative study was to determine how well selected institutional characteristics explain the variance in Hispanic community college students’ transfer rates to 4-year institutions. Due to the rapidly growing Texas Hispanic population, understanding challenges to their educational attainment has become critical. Hispanic community college enrollment in Texas continues to rise, yet these students are not transferring to 4-year institutions at the same rate as other groups. This study analyzed data from the Texas Higher Education Coordinating Board of 50 Texas community colleges to determine how well the independent variables (Hispanic population of each community college campus locale, Hispanic community college student college readiness as indicated by Texas Success Indicator scores, and the percent of Hispanic faculty at each community college) accounted for the variance on the dependent variable (Hispanic community college student transfer rate). Multiple regression was used to determine the magnitude of the relationships between the dependent variable and the combination of all the independent variables. Commonality analysis was then utilized to identify proportions of variance in the dependent variable from combinations of the independent variables. The independent variables together generated a statistically significant regression model on the dependent variable, F(4, 64) = 3.067, p = .023. The R2 coefficient between the independent variables on the dependent variable presented a positive relationship with 17.2% variance. The percent of Hispanic community college faculty was the largest contributor to the variance (62.09%), the strongest factor in accounting for the transfer rates of Hispanic community college students to 4-year universities. Hispanic population of each community college campus locale had the least effect on the dependent variable with a 1.47% variance. The findings of this study support the recent report by the Texas Higher Education Coordinating Board in favor of research and resources for Hispanic educator preparation programs.

Student Number : 0318397E - MSc dissertation - School of Chemical and Metallurgical Engineering - Faculty of Engineering and the Built Environment / An experimental study of the effects of a slag phase on mass transport in a onefifth water model of a 100ton CLU-converter was conducted. The study was a follow up to earlier investigations conducted in the absence of a simulated slag phase. Kerosene (10% by volume) was used to represent the slag phase in the cold model experiments. The presence of a slag phase increased the mixing time of a tracer solution in the bath. The mixing time, defined at 99.66% bath homogeneity, was found to increase with bath height and a lowering gas flow rate. The functional relationship, Tmix = 4.39Q-0.73W0.24H1.12, was established as expressing the effect of gas flow rate (Q), bath weight (W), and bath height (H) on the mixing time (Tmix). The mixing time increased by an average of 16.3% after slag inclusion. The mass transfer parameter [(Reloc,r)0.25(Ret)0.32] values obtained in the absence of a slag phase decreased by an average of 32.2% with slag inclusion. Calculated mass transfer coefficients increased with gas flow rate and a decrease in bath height. The relationship, K Q0.08, showing derived mass transfer coefficient (K) dependence on the gas flow rate (Q) was established. The proportionality constant in the equation was observed to vary with bath height, gas flow rate and sample location. Contour maps representing variation of mass transfer coefficients in the bath regions were produced.

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Doctor of Philosophy / Department of Chemistry / Jun Li / Reduction in electrode size down to nanometers dramatically enhances the detection sensitivity and temporal resolution. Here we explore nanoelectrode arrays (NEAs) and nanoparticles in building high performance biosensors. Vertically aligned carbon nanofibers (VACNFs) of diameter ~100 nm were grown on a Si substrate using plasma enhanced chemical vapor deposition. SiO[subscript]2 embedded CNF NEAs were then fabricated using techniques like chemical vapor deposition, mechanical polishing, and reactive ion etching, with CNF tips exposed at the final step. The effect of the interior structure of CNFs on electron transfer rate (ETR) was investigated by covalently attaching ferrocene molecules to the exposed end of CNFs. Anomalous differences in the ETR were observed between DC voltammetry (DCV) and AC voltammetry (ACV). The findings from this study are currently being extended to develop an electrochemical biosensor for the detection of cancerous protease (legumain). Preliminary results with standard macro glassy carbon electrodes show a significant decrease in ACV signal, which is encouraging. In another study, NEA was employed to capture and detect pathogenic bacteria using AC dielectrophoresis (DEP) and electrochemical impedance spectroscopy (EIS). A nano-DEP device was fabricated using photolithography processes to define a micro patterned exposed active region on NEA and a microfluidic channel on macro-indium tin oxide electrode. Enhanced electric field gradient at the exposed CNF tips was achieved due to the nanometer size of the electrodes, because of which each individual exposed tip can act as a potential DEP trap to capture the pathogen. Significant decrease in the absolute impedance at the NEA was also observed by EIS experiments. In a final study, we modified gold nanoparticles (GNPs) with luminol to develop chemiluminescence (CL) based blood biosensor. Modified GNPs were characterized by UV-Vis, IR spectroscopy and TEM. We have applied this CL method for the detection of highly diluted blood samples, in both intact and lysed forms, which releases Fe[superscipt]3[superscript]+ containing hemoglobin to catalyze the luminol CL. Particularly, the lysed blood sample can be detected even after 10[superscript]8 dilution (corresponding to ~0.18 cells/well). This method can be readily developed as a portable biosensing technique for rapid and ultrasensitive point-of-care applications.

ABSTRACT SWIMMING UPSTREAM: A STUDY OF BLACK MALES AND THE ACADEMIC PIPELINE Rhonda D. Wilkins Post secondary participation and graduation rates of Black males are declining rapidly. Black women, however, are realizing substantial growth in both of these areas and account for the majority of the increase in Black student college enrollment. This qualitative case study addresses the decline in Black male participation in higher education by focusing on six Black men who completed college programs and the academic pipeline that brought them to their degree. The purpose of the research inquiry was to determine various factors that either helped or hindered the academic progression of the six Black male participants. For the study participants the two-year college was a component of their academic pipeline and was assessed based on its function as a conduit aiding degree attainment. The common factors that emerged from the findings as influential to the academic progression of the six Black males were categorized as: (a) personal attributes and perceptions, (b) relationships and external influences, and (c) institutional factors. The personal attributes of the participants included self-efficacy, endurance and resilience, and self-regulation. These attributes were framed within the central context of personal agency. Factors external to the participants consisted of family messages about higher education, role models, mentors and advocates, early exposure to college and participation in athletic sports. The institutional factors that surfaced were insufficient college preparation in high school, contrasts between the climate and culture of the two-year college and four-year institution, the lack of promotion of the transfer function at the two-year college. Race and gender were also considered relative to the men and their experiences with the academic pipeline. The salient factors included: (a) the general social and economic conditions faced by young Black males, (b) the perpetuation of negative or one-dimensional stereotypes in the media, (c) pre-college educational inequities, (d) the lack of assistance with college transition, and (e) the unwelcoming climates and lack of Black faculty at predominately white institutions. The study concluded that Black males may face many hurdles to postsecondary attainment and will therefore require personal, family, community, and institutional forces to push them through the academic pipeline.

The present study was largely concerned with measuring accurate absolute values for the electronic state excitation cross sections in H2O, in the incident electron energy range 15eV to 50eV. It is hoped that these data will eventually help to improve the current state of electron - molecule scattering theory, as well as being useful in various fields of modelling. As an illustration of this latter point, the cross sections determined here were used to calculate quantities of importance in atmospheric modelling, namely, electron energy transfer rates and rates for the excitation of water molecules by auroral secondary electrons.

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