The Interactional Features of Billingual Teacher Talk in the Classroom of Arabic as a Foreign Language

Communication is essential in studying Arabic as a foreign language to make the lesson interactive. This research aimed to identify and assess three aspects. First, the Teacher Talk (TT) interaction feature appeared in the Arabic Education Study Program, Faculty of Tarbiyah and Teacher Training, Raden Intan State Islamic University of Lampung. Second, each lecturer's primary type of TT interaction element. Third, the utilization of code-switching as a component of bilingual learning interactions. This research was a case study of three Arabic lecturers (T1, T2, and T3) who used Google Meets to conduct online learning. Each lecturer was videotaped three times and then examined using Miles and Huberman's qualitative approach. The findings of the L2 investigation demonstrate that 1) T1 produced twelve different types of interaction features. Furthermore, T2 produced eleven different types of interaction features. Finally, T3 produced twelve different types of interaction features. 2) The most dominant TT interaction features in the classrooms by T1 was Scaffolding (18.2 percent), T2 was Display Questions (24.6 percent), and T3 was Confirmation Check (23.1 percent). 3) In the context of bilingual classes, this study also found that L2 lecturers used other interaction features to facilitate interaction, namely code-switching from Arabic (L2) to Indonesian (L1) and vice versa. The total occurrence of code-switching by T1 was 9.1 percent (the least), code-switching by T2 was 27.3 percent, and code-switching by T3 was 63.6 percent (the most dominant). Code-switching can be an excellent alternate approach or interaction tool for facilitating communication in the classroom when learning Arabic; nevertheless, it must be used appropriately and proportionally.

Consistent Tangent Stiffness of a Three-Dimensional Wheel–Rail Interaction Element

Consistent tangent stiffness plays a crucial role in delivering a quadratic rate of convergence when using Newton’s method in solving nonlinear equations of motion. In this paper, consistent tangent stiffness is derived for a three-dimensional (3D) wheel–rail interaction element (WRI element for short) originally developed by the authors and co-workers. The algorithm has been implemented in finite element (FE) software framework (OpenSees in this paper) and proven to be effective. Application examples of wheelset and light rail vehicle are provided to validate the consistent tangent stiffness. The quadratic convergence rate is verified. The speeds of calculation are compared between the use of consistent tangent stiffness and the tangent by perturbation method. The results demonstrate the improved computational efficiency of WRI element when consistent tangent stiffness is used.

Numerical analysis of pipeline response to slow landslides: case study

A numerical analysis is carried out to study the behaviour of pipelines subjected to slow landslides at three at-risk landslide zones of Manitoba Pipeline Network. The pipeline’s longitudinal axis is parallel to the slow landslides at all three research sites. The ground displacements monitored for 5 years are imposed on the pipe using a special purpose pipe–soil interaction element (PSI element) using ABAQUS/Standard. The stiffness of PSI elements is defined based on soil–pipe interface properties according to a 2017 technical report from Pipeline Research Council International Inc. The results of the numerical analysis are compared with the instrumentation data to draw recommendations for future monitoring programs in slow landslide zones.

An experimental investigation into the behavior of sand reinforced by tubular braided structures

This study introduces the tubular braided structure as a new geosynthetic material for sand reinforcement. The performance of a tubular braid under the influence of similar soil–reinforcement interaction mechanisms has been investigated to emphasize the effect of the reinforcement form on the performance of the reinforced soil composite. For this purpose, three series of interaction element tests including direct shear tests, pull-out tests, and soil stress control tests were conducted on the unreinforced and reinforced sand. Finally, the overall performance of the reinforced foundation bed with the planar and tubular reinforcing textile (with similar materials, properties, texture, and areal density) was evaluated through a series of standard plate load tests. The results indicated that the performance of the sand-braid composite was better compared to the similar typical planar reinforcement, except for the case of pull-out test. Tubular braid resulted in the enhanced shear strength of the reinforced soil composites, mobilization of the excess compressive stress in the enclosed soil inside the tubular braids, reduction in the vertical stress level of the footing model transferred down through the soil bed, the increase of the average bearing capacity of the footing model, and a significant reduction in the footing settlement.

A Practical Wheel-Rail Interaction Element for Modeling Vehicle-Track-Bridge Systems

A novel practical element is presented for simulating the vertical wheel-rail interaction (WRI) of vehicle-track-bridge (VTB) coupling systems. The WRI is time- and location-varying, which makes the simulation of the VTB system complicated. The new element simulates the WRI using a location dependent internal resisting force, which enables the finite element (FE) model of the VTB system to remain unchanged in analysis. This element is capable of simulating the nonlinear WRI, the rail irregularity and the ‘additional’ displacement of the rail. The ‘additional’ displacement is the extra displacement caused by the WRI besides that interpolated from the element nodal displacements, which is usually ignored by existing models, but may be non-negligible in some cases. The WRI element is implemented into a general FE software framework, OpenSees, and verified by the dynamic analysis of a simply-supported beam subjected to a moving sprung mass. Furthermore, a realistic VTB system with a moving four-wheel vehicle is investigated to evaluate the cases where the additional displacement and nonlinear WRI should be considered. Finally, using another realistic VTB system subjected to rail irregularities and earthquakes, the effects of rail irregularity and earthquake on the dynamic responses of the WRI system are studied and compared.