Investigation of aerodynamic characteristics of subsonic wings

An analytical strake design procedure is investigated. A numerical solution to the governing strake design equation is used to generate a series of strakes which are tested in a water tunnel to study their vortex breakdown characteristics. The strakes are scaled for use on a half-scale model of the NASA-LaRC general research fuselage with a 44 degrees trapezoidal wing. An analytical solution to the governing design equation is obtained. The strake design procedure relates the potential-flow leading-edge suction and pressure distributions to vortex stability. Several suction distributions are studied and those which are more triangular and peak near the tip generate strakes that reach higher angles of attack before vortex breakdown occurs at the wing trailing edge. For the same suction distribution, a conical rather than three dimensional pressure specification results in a better strake shape as judged from its vortex breakdown characteristics

Professional Development for Science Teachers on Integrating STEM: A Case Study

In the United States, the Next Generation Science Standards (NGSS) bring both commitment and challenges to science education in K-12 schools. New focus areas within the NGSS are engineering education and the integration of multiple disciplines as seen in science, technology, engineering and mathematics (STEM). Providing professional development (PD) is necessary in order to assist K-12 teachers with the implementation of the NGSS in their classrooms (NGSS Lead States, 2013). This case study shares the results of a unique style of PD workshops provided for K-12 teachers on the NGSS and engineering design where participants were immersed in inquiry-based STEM activities with an earth and space science theme. Twenty-six teachers agreed to participate in the study. This qualitative research focused on self-reported data through surveys, interviews, focus groups, and observation of participants during the workshops. Findings from this case study revealed self-reported increases in teachers’ dispositions and self-efficacy regarding their implementation of the NGSS in an integrated STEM teaching context

Influence of microRNAs from Semen on Bovine Fertility

The objective of this study was to compare the miRNAs within sperm cells of bulls considered to have high and low fertility