Experiences of African American male engineering students: a qualitative analysis

Prior to the 1970s, African Americans were essentially invisible in the science and engineering academic and professional communities (Babco, 2001a). The few who did earn degrees in these fields, obtained them primarily from historically Black colleges and universities (HBCUs), and these institutions also served as the primary employer for these graduates in science and engineering (Hines, 1997; Babco, 2001a, 2001b). Since the 1970s, African Americans have made considerable progress, but still are not on a level playing field with White males in terms of opportunities for preparation of science and engineering careers or for employment and advancement in those careers. The purpose of this study was to explore second and third-year African American male engineering students’ perceptions and examine what experiences have contributed to their access to and persistence in engineering. A qualitative research design was employed to gather data necessary to answer the research questions. Eight second and third-year African American male engineering students from Research University (pseudonym) participated in interviews with the researcher. The data from the interviews was used to consider the themes that emerged from the participants. The findings from this study suggest that African American male engineering students at Research University have specific experiences that influence their persistence and academic achievement. Themes identified from the interview data include: (1) pre-college experiences; (2) participation in academic and social networks; (3) institutional programming and organizational support; (4) personal accountability and motivation; and (5) goals outside of engineering. As a result of this research, several future implications are highlighted. These include acknowledging the value of diversity, continued support through organizations, and increased knowledge of best practices.

In situ characterization of sediment oxygen demand across the spectrum of non-resuspension to full resuspension with varying bed shear stress

Sediment oxygen demand (SOD) can be a significant oxygen sink in various types of water bodies, particularly slow-moving waters with substantial organic sediment accumulation. In most settings where SOD is a concern, the prevailing hydraulic conditions are such that the impact of sediment resuspension on SOD is not considered. However, in the case of Bubbly Creek in Chicago, Illinois, the prevailing slack water conditions are interrupted by infrequent intervals of very high flow rates associated with pumped combined sewer overflow (CSO) during intense hydrologic events. These events can cause resuspension of the highly organic, nutrient-rich bottom sediments, resulting in precipitous drawdown of dissolved oxygen (DO) in the water column. While many past studies have addressed the dependence of SOD on near-bed velocity and bed shear stress prior to the point of sediment resuspension, there has been limited research that has attempted to characterize the complex and dynamic phenomenon of resuspended-sediment oxygen demand. To address this issue, a new in situ experimental apparatus referred to as the U of I Hydrodynamic SOD Sampler was designed to achieve a broad range of velocities and associated bed shear stresses. This allowed SOD to be analyzed across the spectrum of no sediment resuspension associated with low velocity/ bed shear stress through full sediment resuspension associated with high velocity / bed shear stress. The current study split SOD into two separate components: (1) SODNR is the sediment oxygen demand associated with non-resuspension conditions and is a surface sink calculated using traditional methods to yield a value with units (g/m2/day); and (2) SODR is the oxygen demand associated with resuspension conditions, which is a volumetric sink most accurately characterized using non-traditional methods and units that reflect suspension in the water column (mg/L/day). In the case of resuspension, the suspended sediment concentration was analyzed as a function of bed shear stress, and a formulation was developed to characterize SODR as a function of suspended sediment concentration in a form similar to first-order biochemical oxygen demand (BOD) kinetics with Monod DO term. The results obtained are intended to be implemented into a numerical model containing hydrodynamic, sediment transport, and water quality components to yield oxygen demand varying in both space and time for specific flow events. Such implementation will allow evaluation of proposed Bubbly Creek water quality improvement alternatives which take into account the impact of SOD under various flow conditions. Although the findings were based on experiments specific to the conditions in Bubbly Creek, the techniques and formulations developed in this study should be applicable to similar sites.