INVESTIGATING COGNITIVE AND METACOGNITIVE STRATEGY USE DURING AN ENGLISH PROFICIENCY TEST

 This paper reports on the results of a study of cognitive and metacognitive strategy use and its effect on the students’ test performance at the tertiary level in a Chinese EFL context. A 18-item survey involving 526 undergraduate non-English majors revealed that: (1) the students had a medium use of both cognitive and metacognitive strategies during the test; (2) cognitive and metacognitive strategy use was closely related to each other, but neither was a predictor for the other; and (3) though cognitive and metacognitive strategy use significantly correlated with the students’ performance in certain parts of the proficiency test, only the metacognitive strategy of evaluating one’s performance proved to be a positive predictor of the students’ performance in listening and reading comprehension and the overall written test. Based on the results, some implications and suggestions for future research are discussed. Keywords: Strategy use; Cognitive; Metacognitive; Test performance; Tertiary

Bubble Flow Analysis of High Speed Cylindrical Roller Bearing under Fluid-Solid Thermal Coupling

Heat generation model of high speed cylindrical roller bearing is constructed by calculating the local friction in the bearing. Bubble flow calculation model of roller bearing considering fluid-solid thermal coupling is constructed based on two-body fluid model and k-ε turbulent model, in which diameter and size of bubbles, breakup, and coalescence model of bubbles are considered. Using dynamic mesh method, a new method for evaluating bearing temperature is set up treating the rolling elements as moving heat sources. Based on these models and finite element method, bubble flow of a high speed roller bearing is studied based on FLUENT software. The numerical study reveals the relationship between velocity of bearing, air volume fraction, and velocity and pressure of oil-air flow. An increase of air content in the oil produces a lower pressure at the bearing outlet while the exit fluid velocity increases. When fluid-solid thermal coupling effect is considered, velocity and pressure at outlet of the bearing both become larger, while temperature of bearing is lower than that without coupling. In comparison, the coupling effects on flow pressure and temperature are obvious. For a given rotating speed, there is an optimal value for air volume fraction, such that temperature rise of the bearing reaches the lowest value. Experiments verify the outcomes of the method presented in this paper

Investigating Cognitive and Metacognitive Strategy Use During an English Proficiency Test

This paper reports on the results of a study of cognitive and metacognitive strategy use and its effect on the students\u27 test performance at the tertiary level in a Chinese EFL context. A 18-item survey involving 526 undergraduate non-English majors revealed that: (1) the students had a medium use of both cognitive and metacognitive strategies during the test; (2) cognitive and metacognitive strategy use was closely related to each other, but neither was a predictor for the other; and (3) though cognitive and metacognitive strategy use significantly correlated with the students\u27 performance in certain parts of the proficiency test, only the metacognitive strategy of evaluating one\u27s performance proved to be a positive predictor of the students\u27 performance in listening and reading comprehension and the overall written test. Based on the results, some implications and suggestions for future research are discussed

Stratification Prediction and Bottom Boundary Layer Dynamics over the Texas-Louisiana Continental Shelf

The bottom boundary layer is an unstratified thin layer above the sea floor, separated from the more strongly stratified interior. Formation of a thin bottom boundary layer in the presence of stratification and a sloping bottom is common, and well characterized by theory. This thin layer is an important source of mixing over the continental shelf, and it plays a fundamental role in several continental shelf physical and biogeochemical processes, such as buoyancy advection, bottom material transport and hypoxia formation. In this research, Both observations and numerical models are used to study models' ability of reproducing observed stratification and bottom boundary layer dynamics over the Texas-Louisiana shelf. Simulated vertical stratification, which is also representing the vertical density structure, was first evaluated since it directly controls the bottom boundary layer structure itself and is important for other bottom boundary layer dynamics. A new metric, the histogram of vertical stratification, is introduced in this research to evaluate the models' ability of reproducing observed stratification in a bulk sense. The improvement in model performance is attributed to the finer horizontal and temporal resolutions of a model, while factors like open boundary conditions and vertical resolutions are modified without any improvement in the ability of the model to simulate observed stratification. Towed, undulating CTD profiles collected during Mechanisms Controlling Hypoxia (MCH) program also detected mid-water oxygen minima in many transects. These intrusions are connected with the bottom boundary layer and follows the pycnocline seaward as a mid-water column tongue of low oxygen. We calculate convergence within the bottom boundary layer relative to density surfaces using the simulated results; there is a convergence in the bottom boundary layer at the location where the pycnocline intercepts the bottom, creating an injection of bottom boundary layer water into the pycnocline. Convergent flow at the bottom, relative to isopycnal surfaces, is strongest in the density classes associated with the oxygen minimum layer. We believe these mid-water oxygen minima are actually intrusions of low oxygen protruding from the bottom boundary layer via buoyancy advection driven convergence, following the main pycnocline