Abstract: The overrepresentation of African American males at risk for academic challenges and special education services, disciplinary actions, dropout rates, and incarceration is an alarming trend in the United States that has been ongoing for over 40 years. Research has shown correlation exists between a teachers’ cultural competence and a students’ positive academic and behavioral outcomes (Boutte & Hill, 2006; Howard & Terry, 2011; Rychly & Graves, 2012). However, many teachers are inadequately prepared with appropriate content knowledge, experience with culturally relevant practices, and training to address culturally and linguistically diverse students’ learning needs (Sobel et al., 2011). A cultural learning gap between teachers and students, along with, inadequate preparation can limit the choices of effective culturally responsive practices. An educator’s beliefs, attitudes, and expectations can have a major impact on student outcomes. (Ladson-Billings, 2006). Culturally responsive teachers understand the impact culture has on the educational system and place culture at the center as they investigate techniques needed for improving the performance of underachieving students of color (Bonner et al., 2018). The aim of this study was to examine perceptions of high school African American males receiving special education services or at risk for academic challenges related to teacher responsiveness to cultural diversity. This study used a phenomenological qualitative method to gain insight into the lived experiences of African American males. Findings, limitations, suggestions for future research, and implications for practice will be discussed.
A supercritical carbon dioxide (sCO2) Brayton power cycle is considered as one of the promising energy conversion systems for a number of applications such as Concentrated Solar Power (CSP) plants due to its high thermodynamic efficiency and small equipment size. The compact heat exchangers such as Printed Circuit Heat Exchangers (PCHEs) with micro-channel geometry are suitable for coupling different heat sources to a sCO2 Brayton power cycle. The objective of this study is to design and optimize an advanced PCHE micro-channel geometry and topology for a sCO2 Brayton cycle. This work is concerned with the design where both sides of the plate are etched forming a double-etched micro-channel design configuration. In this advanced micro-channel topology, shim plates are needed to construct a PCHE stack using diffusion bonding.
Thermo-hydraulic performance of semi-circular micro-channel and advanced semi-circular and circular double-etched micro-channel geometries, and maximum stress, were determined. The results obtained for the advanced double-etched microchannel geometry were compared to the “conventional” semi-circular single-etched (single-side etched) micro-channel design for the counter-flow arrangement. Using ANSYS-Workbench, a multi-objective optimization algorithm employing NSGA-II and Response Surface Approximation (RSA) as a surrogate model was used for design and optimization of the advanced double-etched micro-channel PCHE geometry.
Thermal stress has been identified as one of the major failure causes in the power module. It is generated from the mechanical strain by severely varying temperatures at different loci in the power module and the different coefficients of the thermal expansion of materials, where the varying temperatures result from the real-time power loss across the power converter. This thermal stress accelerates the degradation of semiconductor devices, downgrades the system quality and efficiency, and eventually causes catastrophic system breakdowns and extensive economic losses. Therefore, this research is dedicated to investigating both local control level methods and system level strategies to ameliorate the real-time power loss in order to reduce the thermal stress in the power module, thereby extend the component lifetime and enhance the system reliability. A finite-control-set model predictive control (FCS-MPC) is introduced and deductively investigated from the local control level. Its variable switching frequency property is derived through the geometry analysis on the voltage vector space. It realizes the switching frequency variation autonomously by the loading power. By taking advantage of this property, the power loss is leveled in the real-time operation by FCS-MPC, and a more mitigated thermal profile is acquired compared with the one by the conventional controller. Furthermore, a centralized thermal stress oriented dispatch (TSOD) system level strategy is proposed for multiple paralleled distributed energy resource systems, which helps to reduce the thermal stress in the power module of paralleled converters. It is thermal stress oriented and takes effect according to the real-time junction temperature variation, the health condition of the individual converter, and the system operation. Two local control level methods, the switching frequency variation and the reactive power injection, are imported separately as the dispatch algorithm to generate the expected power loss. Dealing with the varying mission profile, the more mitigated thermal profiles are achieved for all converters with the assistance of the proposed TSOD strategy.
This dissertation explores the association between Founder Social Identity and the two leading component measures of market orientation: customer and competitor orientation. Using the typology of entrepreneurial identities developed by Fauchart and Gruber, this study empirically examines how the degree by which individuals are driven by social motivations captured by the darwinian, communitarian, and missionary founder social identity types predicts the degree by which entrepreneurs enact a customer and competitor orientation. To test this, data was collected from 492 entrepreneurs of small to medium size enterprises across all industries. Results suggest that the social motivations captured by the darwinian founder social identity type are positively related to customer and competitor orientation, the social motivations captured by the communitarian founder social identity type are positively related to competitor orientation, and that the degree to which an individual aligns with the missionary founder social identity type is positively related to customer orientation. These findings extend prior literature suggesting that the social motivations that drive entrepreneurship impact business processes and outcomes by demonstrating their link to key marketing activities.
Localization and communication are critical components for functioning autonomous robots. The infrastructure required for these operations commonly includes global positioning system (GPS) and easily recognizable and re-identifiable landmarks. However, these types of infrastructures are not always readily available. This research has developed a deploy-able electronic way-point system dubbed ’BreadCrumbs’. BreadCrumbs function as electronic landmarks that can provide localization and communication capabilities to a robot in environments where such infrastructure is not inherently present. When deployed by a forward moving agent with a set destination, the BreadCrumbs also form a series of way-points which reduce the possible state space an autonomous robot must search through when path planning in an unknown or unmapped environment. The BreadCrumbs are self localizing and have several methods for initial location determination based on the environment they are placed in. GPS is not required for the BreadCrumbs to function and, once established, they can function as landmarks for autonomous robots by providing range data from radio signal strength with a path loss exponent determined through a Deep Deterministic Policy Gradient algorithm.
Human cardiac myosin has two isoforms, α and β, sharing significant sequence similarity, but different in kinetics. Small differences in the sequence are responsible for distinct local inter-residue interactions within α and β isoforms, leading to such a dramatic difference in the rate of ADP release. Our analysis of structural kinetics of α and β isoforms using molecular dynamics simulations revealed distinct dynamics in SH1:SH2 helix region, loop 1 region, and loop I289-D324 region of myosin head. We identified permanent salt bridges in these regions on β-isoform, which are not present in the α-isoform. We hypothesized that the isoform-specific electrostatic interactions play a role in the difference of kinetic properties of myosin isoforms. We prepared R694N, E4Q, I303V:I313V,and D208Q:K450L mutants in the β-isoform background to destabilize electrostatic interactions in the proposed regions of the myosin head. We recombinantly expressed Wild type (WT) and the mutants of the human car- diac myosin head construct (1-843 amino acid residues) in differentiated C2C12 cells. Using the transient kinetics assays, we measured the kinetics of ADP release from actomyosin in the WT and mutant constructs of human cardiac myosin β-isoform. Mutant R694N showed faster rate of ADP release from actomyosin, compared to the wild type and other mutants, thus confirming that electrostatic interactions within the force-generating region of human cardiac myosin regulate ADP release and the duration of the strongly bound state of actomyosin.
Most of the coagulation studies done thus far were either site-specific or focused on only one variable and hence do not apply to real-world conditions. Developing a universal and practical model of coagulation has been a near-impossible task because 1) water is a chemically complex medium that varies spatially and temporally 2) the sheer number of factors and their interactions that determine the performance of the coagulant. The focus of this research is to develop a general model for coagulation with aluminum sulfate that has practical applications. The goal is also to identify the parameters that control optimum coagulation conditions while considering the removal of particulate (e.g., bacteria) and dissolved (e.g., organic matter) contaminants as well as chemical costs.
In this paper, we have applied case cohort study design to semiparametric additive hazard models to study the effect of covariates on failure times. We have considered the phase one covariates to have both time varying and constant effect on failure time while phase two covariates have constant effect. We have applied Augmented Inverse Probability Weighted (AIPW) method to estimate the model
parameters and compared the result with widely adopted Inverse Probability Weighted (IPW) method. Our simulation study shows that AIPW estimation is more consistent than IPW estimation method. The method is applied to analyze the RV144 vaccine trial data to assess whether immune response and behavioral risk level has effect on HIV-1 infection.
The purpose of this qualitative study was to explore professional development from the perspective of instructional leaders to identify if the assumptions of Knowles’s (1990) Adult Learning Theory were present in the planning and implementation of continuing education. A qualitative case study research design was utilized, and the research setting was dependent on the participants and the locations in which they were contracted to conduct continuing education sessions with teachers. The instructional leaders were committed to plan and present professional development at three different suburban schools surrounding a city in the Southeastern United States. The participants in the study were instructional leaders and educational consultants with at least 10 years of experience who work across school districts with multiple elementary, middle, and high school sites in suburban and urban districts. Data sources included two rounds of interviews, observations of planned and implemented professional development, and document analysis of staff development materials. The data was analyzed using thematic analysis that included within-case and cross-case investigation.
This dissertation investigates a newly emerging phenomenon in Chinese higher education in which a Chinese university partners with an overseas university to open a new university campus in China which began in 2004. This form of university was established in the context of economic growth and education reform in Chinese society. It has brought a change to the rebuilding of nonpublic higher education in China since the late 1980s. It also reinforces the emphasis on internationalization and diversification of higher education set by Chinese government for the 21st century. However, as a joint venture in higher education, this form of education is still unknown to many education scholars with respect to its formation mechanisms and motivations. Moreover, given the changing landscape of Chinese higher education, the current status and future prospects of this type of university are worthy of study considering its benefits as well as challenges for Chinese and the global higher education development. What is more, the social, economic, and policy implications of these universities are even more enormous than its education perspective.
This dissertation is an exploratory case study involving intensive interviews with seven administrators and nine students from four institutions in this study along with content analysis of mission statements and school documents involving all nine institutions in this group. Findings suggest that the emergence of joint venture universities is consistent with the growing trend of globalization and internationalization in worldwide higher education development. Motivations and goals of institutions in pursuing this cooperation may vary among countries. China’s governmental involvement in this kind of education signifies a new trend in higher education collaboration that incorporates governmental interest in political, economic, and global pursuits rather than focusing on the education per se. Thus, this type of joint venture universities is neither public nor private. An unexpected finding is that the emergence of this form of education did not improve education inequality existing in Chinese higher education due to geographical location but reinforce the reproduction of inequality. Also, the small number of special joint venture universities in China seem to aim more for advancing China’s international goals to engage on the global stage, foster China’s active globalization efforts, and prepare Chinese students to be academically and socially ready for globalization. These findings thus have substantial implications for policymakers in relevant areas and help them in policymaking decisions.
