4,643 research outputs found
The Experiences Of Black Males In Honors Colleges
The purpose of this study is to explore the experiences of Black Males in honors colleges. Specifically this study aims to highlight the successes, challenges, and common experiences of Black males in honors colleges. To this end, the researcher interviewed six Black men in an honors college located in a predominantly White institution in the southeast. This study sought to share a story of success to counteract the majoritarian narrative of Black male underachievement. Critical Race Theory provided a framework and lens to help understand the emergent themes and findings. Through interviews with the study participants the following seven themes emerged; 1) the importance of faculty, staff, and student relationships 2) involvement in civic engagement, social justice, and advocacy 3) the role of advanced placement and international baccalaureate courses in preparing students for college 4) the importance of personal and familial expectations 5) the role of beyond the classroom opportunities in identity development 6) lack of visibility and representation 7) navigation of stereotypes, microaggressions, and racism. These seven themes help us to understand the experiences of the population being studied and come together to help highlight the successes of the study participants
Angiotensin II and VEGF are Involved in Angiogenesis Induced by Short-Term Exercise Training
Results from our laboratory have suggested a pathway involving angiotensin II type 1 (AT1) receptors and vascular endothelial growth factor (VEGF) in angiogenesis induced by electrical stimulation. The present study investigated if similar mechanisms underlie the angiogenesis induced by short-term exercise training. Seven days before training and throughout the training period, male Sprague-Dawley rats received either captopril or losartan in their drinking water. Rats underwent a 3-day treadmill training protocol. The tibialis anterior and gastrocnemius muscles were harvested under anesthesia and lightly fixed in formalin (vessel density) or frozen in liquid nitrogen (VEGF expression). In controls, treadmill training resulted in a significant increase in vessel density in all muscles studied. However, the angiogenesis induced by exercise was completely blocked by either losartan or captopril. Western blot analysis showed that VEGF expression was increased in the exercised control group, and both losartan and captopril blocked this increase. The role of VEGF was directly confirmed using a VEGF-neutralizing antibody. These results confirm the role of angiotensin II and VEGF in angiogenesis induced by exercise
Reading the Word and the World through Graphic Novels: A Graphic Portrayal of Young Adult Literacy Development in a Ninth Grade English Literature Classroom
This study presents a view of reading instruction based on investigating motivation and engagement related to adolescent literacy practices through graphic novels. A case study utilizing the graphic novels grounded in the theoretical approach of critical literacy demonstrated increases in motivation toward reading from a more critical social lens. Participants in this case study were chosen from a set of ninth grade literature classes in a rural high school. The students were placed as a result of the random selection of heterogeneously mixed student abilities providing a rich mix of perspectives and motivational levels among the students. Allowing students to view character experiences in graphic novels through both graphic and traditional text opened possibilities for opportunities in improving reading comprehension by increasing motivation and engagement. A change from traditional viewpoints that focus on mastery of skills to a critical view about text has the potential to allow adolescent students to question, to challenge, and to seek the unknown which in turn motivates this same learner to read. The primary findings include: (1) a positive connection between student attitudes toward reading and their engagement with text; (2) the reaction of students to elements of popular culture that included graphic novels created a bridge to traditional literature and improved student relationships with reading standard text; (3) challenging students to view text whether from a traditional standpoint or through the medium of sequential comic art supported the students\u27 ability to redefine reading from critical perspectives; (4) critical readings of traditional text and graphic novels gave voice to the students as direct agents of their own learning particularly as it related to real-world social issues; and (5) student motivation toward independent and academic reading was improved by teacher passion and commitment to the understanding and connection of text and graphics to the literature formats. Further study is recommended in the areas of the impact of the teacher on student motivation. Additional study is recommended related to the use of popular culture to enhance learning and motivation
Summary of LOX/CH4 Thruster Technology Development at NASA/MSFC
In recent years, a variety of injectors for liquid oxygen (LOX) and methane (CH4) propellant systems have been designed, fabricated, and demonstrated with hot-fire testing at Marshall Space Flight Center (MSFC). Successful designs for liquid methane (LCH4) and gaseous methane (GCH4) have been developed. A variety of chambers, including a transpiration cooled design, along with uncooled ablatives and refractory metals, have also been hot-fire tested by MSFC for use with LOX/LCH4 injectors. Hot-fire testing has also demonstrated multiple ignition source options. Heat flux data for selected injectors has been gathered by testing with a calorimeter chamber. High performance and stable combustion have been demonstrated, along with designs for thrust levels ranging from 500 to 7,000 lbf. The newest LOX/CH4 injector and chamber developed by MSFC have been fabricated with additive manufacturing techniques and include unique design features to investigate regenerative cooling with methane. This low cost and versatile hardware offers a design for 4,000 lbf thrust and will be hot-fire tested at MSFC in 2015. Its design and operation can easily be scaled for use in systems with thrust levels up to 25,000 lbf
High Thermal Conductivity NARloy-Z-Diamond Composite Liner for Advanced Rocket Engines
NARloy-Z (Cu-3Ag-0.5Zr) alloy is state-of-the-art combustion chamber liner material used in liquid propulsion engines such as the RS-68 and RS-25. The performance of future liquid propulsion systems can be improved significantly by increasing the heat transfer through the combustion chamber liner. Prior work1 done at NASA Marshall Space Flight Center (MSFC) has shown that the thermal conductivity of NARloy-Z alloy can be improved significantly by embedding high thermal conductivity diamond particles in the alloy matrix to form NARloy-Z-diamond composite (fig. 1). NARloy-Z-diamond composite containing 40vol% diamond showed 69% higher thermal conductivity than NARloy-Z. It is 24% lighter than NARloy-Z and hence the density normalized thermal conductivity is 120% better. These attributes will improve the performance and life of the advanced rocket engines significantly. The research work consists of (a) developing design properties (thermal and mechanical) of NARloy-Z-D composite, (b) fabrication of net shape subscale combustion chamber liner, and (c) hot-fire testing of the liner to test performance. Initially, NARloy-Z-D composite slabs were made using the Field Assisted Sintering Technology (FAST) for the purpose of determining design properties. In the next step, a cylindrical shape was fabricated to demonstrate feasibility (fig. 3). The liner consists of six cylinders which are sintered separately and then stacked and diffusion bonded to make the liner (fig. 4). The liner will be heat treated, finish-machined, and assembled into a combustion chamber and hot-fire tested in the MSFC test facility (TF 115) to determine perform
Swirl Coaxial Injector Testing with LOX/RP-J
Testing was conducted at NASA fs Marshall Space Flight Center (MSFC) in the fall of 2012 to evaluate the operation and performance of liquid oxygen (LOX) and kerosene (RP ]1) in an existing swirl coaxial injector. While selected Russian engines use variations of swirl coaxial injectors, component level performance data has not been readily available, and all previously documented component testing at MSFC with LOX/RP ]1 had been performed using a variety of impinging injector designs. Impinging injectors have been adequate for specific LOX/RP ]1 engine applications, yet swirl coaxial injectors offer easier fabrication efforts, providing cost and schedule savings for hardware development. Swirl coaxial elements also offer more flexibility for design changes. Furthermore, testing with LOX and liquid methane propellants at MSFC showed that a swirl coaxial injector offered improved performance compared to an impinging injector. So, technical interest was generated to see if similar performance gains could be achieved with LOX/RP ]1 using a swirl coaxial injector. Results would allow such injectors to be considered for future engine concepts that require LOX/RP ]1 propellants. Existing injector and chamber hardware was used in the test assemblies. The injector had been tested in previous programs at MSFC using LOX/methane and LOX/hydrogen propellants. Minor modifications were made to the injector to accommodate the required LOX/RP ]1 flows. Mainstage tests were performed over a range of chamber pressures and mixture ratios. Additional testing included detonated gbombs h for stability data. Test results suggested characteristic velocity, C*, efficiencies for the injector were 95 ]97%. The injector also appeared dynamically stable with quick recovery from the pressure perturbations generated in the bomb tests
If you dont succeed, should you try again? : the role of entrepreneurial experience in venture survival
There remains considerable scholarly debate about the role that prior entrepreneurial experience
plays in new venture survival. Drawing on entrepreneurial learning theories, we use
panel data on 8,400 new ventures to investigate the impact of four different types of prior entrepreneurial
experience (portfolio, serial, failure (bankruptcy/voluntary dissolution) and a
mix of success (portfolio/serial) and failure (prior bankruptcy/dissolution) on venture survival
outcomes. We find that previously failed entrepreneurs are less likely to survive and, in common
with entrepreneurs with mixed prior experiences, are more likely to experience bankruptcy.
We find that portfolio and serial experience is unrelated to survival or avoiding bankruptcy.
Conclusions for entrepreneurship scholars, entrepreneurs and stakeholders are discussed
Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines
This paper describes the process development for fabricating a high thermal conductivity NARloy-Z-Diamond composite (NARloy-Z-D) combustion chamber liner for application in advanced rocket engines. The fabrication process is challenging and this paper presents some details of these challenges and approaches used to address them. Prior research conducted at NASA-MSFC and Penn State had shown that NARloy-Z-40%D composite material has significantly higher thermal conductivity than the state of the art NARloy-Z alloy. Furthermore, NARloy-Z-40 %D is much lighter than NARloy-Z. These attributes help to improve the performance of the advanced rocket engines. Increased thermal conductivity will directly translate into increased turbopump power, increased chamber pressure for improved thrust and specific impulse. Early work on NARloy-Z-D composites used the Field Assisted Sintering Technology (FAST, Ref. 1, 2) for fabricating discs. NARloy-Z-D composites containing 10, 20 and 40vol% of high thermal conductivity diamond powder were investigated. Thermal conductivity (TC) data. TC increased with increasing diamond content and showed 50% improvement over pure copper at 40vol% diamond. This composition was selected for fabricating the combustion chamber liner using the FAST technique
NWSA News
TASKFORCE REPORTS
Elizabeth Baer
Initial Efforts of theCurriculum Taskforce
The Curriculum Taskforce is fortunate in having several strongly involved participants: the PreK-12, Lesbian, and Student Caucuses, and the New York and Northwest regions. To date, several of the participants have singled out areas of prime concern to them and are inviting those interested to send materials, ideas, and support
The Association of Changes in Local Health Department Resources With Changes in State-Level Health Outcomes
We explored the association between changes in local health department (LHD) resource levels with changes in health outcomes via a retrospective cohort study. We measured changes in expenditures and staffing reported by LHDs on the 1997 and 2005 National Association of County and City Health Officials surveys and assessed changes in state-level health outcomes with the America’s Health Rankings reports for those years. We used pairwise correlation and multivariate regression to analyze the association of changes in LHD resources with changes in health outcomes. Increases in LHD expenditures were significantly associated with decreases in infectious disease morbidity at the state level (P=.037), and increases in staffing were significantly associated with decreases in cardiovascular disease mortality (P=.014), controlling for other factors
- …