160 research outputs found

    Examining the Relationship Between CBI Methods and Student Academic Achievement Scores in Higher Education

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    The international tertiary community continues to experience a substantial growth in ESL students, which represent a significant portion of total enrollment. To meet this demand for bilingual education EAP (English for Academic Purpose) programs such as CBI (content-based instruction) curriculum have been widely adopted as the preferred pedagogical approach to address this growing trend in higher education. Despite this popularity, there is a lack of longitudinal research on the efficacy of CBI courses, that link this approach to sustained improvement on student academic achievement scores. This study incorporates a mixed- methods design that investigates the academic performance of two sample groups over a three- year (2014-2016) period, by using ex post facto academic GPA scores. The quasi-experimental sample is compared to the control group after receiving the CBI intervention in the second semester of the participants 2014 freshmen year. The findings suggest a positive sustained relationship between CBI curriculum and increased academic performance post intervention. Additionally, a survey and semi structured interviews were conducted on students and faculty to evaluate perceptions of CBI’s efficacy to promote enhanced L2 proficiency and improved long- term academic achievement scores. The results of this effort support the quantitative analysis, and indicate the majority of participants strongly consider CBI methods as a suitable pedagogical technique, to acquire language and content knowledge while enhancing long-term academic performance. This study was unique because it investigated the longitudinal impact of CBI methods on student performance in Mainland China. This research may inform future practitioners, administrators, and policy makers when developing ESL programs in the higher education environment

    Theoretical and experimental investigation of additive drag

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    The significance of additive drag is discussed and equations for determining its approximate value are derived for annular and open-nose inlets. Charts are presented giving values of additive drag coefficient over a range of free-stream Mach numbers for open and for annular-nose inlets with conical flow at the inlet. The effects on additive drag of variable inlet-total-pressure recovery and static pressures on the centerbody are investigated and an analytical method of predicting the variation of pressure on the centerbody with mass-flow ratio is given. Experimental additive-drag values are presented for a series of 20 degree and 25 degree cone half-angle inlets and one open-nose inlet operating at free-stream Mach numbers of 1.8 and 1.6. A comparison with the theoretical values of additive drag shows excellent agreement for the open-nose inlet and moderately good agreement for the annular inlets. (author

    Theoretical and experimental investigation of additive drag

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    The significance of additive drag is discussed and equations for determining its approximate value are derived. Charts are presented giving values of additive drag for open-nose inlets and for annular-nose inlets with conical flow at the inlet. The effects of variable inlet total-pressure recovery and static pressures on the center body are investigated, and an analytical method of predicting the variation of pressure on the center body with mass-flow ratio is given. Experimental values of additive drag are compared with values predicted by the methods

    Models of Giant Planet formation with migration and disc evolution

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    We present a new model of giant planet formation that extends the core-accretion model of Pollack etal (1996) to include migration, disc evolution and gap formation. We show that taking into account these effects can lead to a much more rapid formation of giant planets, making it compatible with the typical disc lifetimes inferred from observations of young circumstellar discs. This speed up is due to the fact that migration prevents the severe depletion of the feeding zone as observed in in situ calculations. Hence, the growing planet is never isolated and it can reach cross-over mass on a much shorter timescale. To illustrate the range of planets that can form in our model, we describe a set of simulations in which we have varied some of the initial parameters and compare the final masses and semi-major axes with those inferred from observed extra-solar planets.Comment: Accepted in Astronomy & Astrophysic

    Stationary bathtub vortices and a critical regime of liquid discharge

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    A modified Lundgren model is applied for the description of stationary bathtub vortices in a viscous liquid with a free surface. Laminar liquid flow through the circular bottom orifice is considered in the horizontally unbounded domain. The liquid is assumed to be undisturbed at infinity and its depth is taken to be constant. Three different drainage regimes are studied: (i) subcritical, where whirlpool dents are less than the fluid depth; (ii) critical, where the whirlpool tips touch the outlet orifice; and (iii) supercritical, where surface vortices entrain air into the intake pipe. Particular attention is paid to critical vortices; the condition for their existence is determined and analysed. The influence of surface tension on subcritical whirlpools is investigated. Comparison of results with known experimental data is discussed

    Boundary layer measurements at supersonic nozzle throats

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    Wall static pressure measurements and boundary layer pitot pressure surveys were made near the throat of a flexible wall supersonic wind-tunnel nozzle at three settings having throat radii of curvature from 33 to 59 inches. It is found that the longitudinal static pressure gradient at the nozzle throat calculated from one-dimensional flow theory agreed with the measured wall static pressure gradient. The boundary-layer velocity profiles at the nozzle throat are presented and discussed. The boundary layers were turbulent and 0.046 to 0.107 inch thick. It is found that the boundary-layer momentum thickness at the nozzle throat calculated using the momentum-integral-equation and several approximations agrees with the values determined from the measured boundary layer profiles. Finally, it is noted that in spite of the different static pressure gradients, the boundary-layer velocity profiles for the different nozzle settings are similar, and it is shown analytically that this similarity is to be expected
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