THE IMPLEMENTATION OF COMMUNICATIVE LANGUAGE TEACHING IN THE CONTEXT OF ONLINE LEARNING: A LITERATURE REVIEW

With the occurrence of the COVID-19 crisis, there has been dramatically growth and adoption of online education. As a consequence of the epidemic, institutes have been compulsory to close, and teaching and learning have changed fully to home studying. As a result, numerous educational institutions have adopted online teaching and learning on a massive scale. To combine the Communicative Language Teaching (CLT) approach with a framework of computer-assisted language learning seems to be the best strategy during a coronavirus outbreak. This study offers a survey of the literature on Communicative Language Teaching in the situation of online teaching and studying. This paper begins with an overview, definition, and characteristics of CLT. It then examines how CLT can be beneficial in a virtual classroom: advantages and disadvantages. Besides, it discusses the approaches to using CLT in online teaching and learning. This paper's goal is to provide an effective overview that can be used for online language instruction. The study will add to our understanding of Communicative Language Teaching and its use in an online setting.  Article visualizations

Influence of transition metal ions on the oxidation of L-proline amino acid initiated by HO● radical in the aqueous phase

The oxidation of L-proline (Pro) amino acid by HO● radical and the influence of transition metal ions on this process have been investigated by using the density functional theory (DFT) method at the M05-2X/6-311++G(3df,3pd)//M05-2X/6-311++G(d,p) level of theory in the aqueous phase. The results show that Pro can be oxidized by HO● radical via formal hydrogen transfer (FHT) reactions at multiple sites, with the highest branching ratio found at hydrogen atoms H10 (30.04%) and H12 (25.60%). The overall rate constant at 298.15K is determined as 6.04 × 108 M-1 s-1, and its expression from 250 to 400K is k=1.634×T2.990×exp[1.591(kcal mol-1)/RT] M-1 s-1. In addition, Pro tends to form the stable mono- and bidentate complexes with both Fe and Cu ions via the–COO functional group of dipole-salt form, which significantly increases when the concentration of Pro doubles. The most stable Cu(II)-Pro complexes have high potential oxidant risks by enhancing the HO● radical formation when reducing agents such as superoxide anion, or ascorbate anion are available. Besides, the oxidant reaction of the high oxidation state complexes, including Fe(III)-Pro and Cu(II)-Pro, by HO● radical as FHT reactions have a lower rate constant than that of free-ligand, while the ones for SET reactions is extremely low even though they are higher than that of free-ligand. As a result, the Pro’s oxidation enhancement of these complexes is negligible. In contrast, the rate constants of SET reactions of low oxidation state complexes (i.e., Fe(II)-Pro and Cu(I)-Pro) are likely to be many times faster than the oxidation rate of free ligand, and thus, these complexes promote the oxidation of Pro. Finally, the FHT chemical nature of HO-initiated oxidation for free Pro, Fe(III)-Pro, and Cu(II)-Pro complexes are evaluated to determine whether these processes occur via hydrogen atom transfer (HAT) or proton-coupled electron transfer (PCET)

Do the transition metal ions (Fe, Cu) influence on the oxidation of L-proline amino acid initiated by HO radical in the aqueous phase?

International audienc

Numerical Study of Bearing Strength of Infilled Concrete in Large Diameter CFST Column Reinforced by Shear Stoppers

Ensuring an adequate bond between the steel tube and infilled concrete interface plays an essential role in achieving composite action for concrete-filled steel tubular (CFST) columns. Thus, this study proposes a new type of large diameter CFST column where the steel tube is reinforced by shear stoppers. The bearing strength of the infilled concrete is the decisive factor in evaluating the overall working efficiency between infilled concrete and steel tube. In this paper, we use nonlinear finite element analysis (NFEA) to investigate the bearing strength of the infilled concrete concerning the ratio of the steel tube’s diameter to its thickness (D/t), the number of shear stoppers N, the height of the shear stopper hb, and the concrete compressive strength (CCS) fc′. Our results show that the influencing factors on the bearing strength of the infilled concrete were arranged in descending order as follows: the number of shear stoppers, the height of shear stopper, the CCS, and the D/t ratio. We also analyze and highlight some significant parameters related to the bearing strength of infilled concrete

Seismic Performance of Exterior RC Beam–Column Joints Retrofitted using Various Retrofit Solutions

Abstract Beam–column joints in existing concrete buildings might not satisfy the design requirements for seismic reinforcement details specified in current seismic design codes. Thus, in this study, various retrofit solutions for existing exterior beam–column joints with non-seismic details were developed: head re-bars anchoring, carbon fiber reinforced polymer (CFRP) wrapping, haunch retrofit element, and steel jacketing with various shapes and sizes. To investigate the seismic performance of exterior joints strengthened with the proposed retrofit solutions, seven half-scale exterior reinforced concrete beam–column joints including one control specimen and six retrofitted specimens were fabricated and tested under cyclic loading simulating earthquake loading. The test results showed that the proposed retrofit solutions could partially enhance the seismic capacity of the beam–column joints: steel jackets could increase deformation and load-carrying capacities; steel haunch elements could increase the load-carrying capacity, stiffness, and dissipated energy; and head re-bar anchoring and CFRP wrapping did not significantly effect on the seismic capacity of the beam–column joints

An Improvement of the Camshift Human Tracking Algorithm Based on Deep Learning and the Kalman Filter

Automated human tracking in real time has been applied in many areas such as security, surveillance, traffic control, and robots. In this paper, an improvement of the Camshift human tracking algorithm based on deep learning and the Kalman filter is proposed. To detail an approach by using YOLOv4-tiny to detect a human in real time, Camshift is used to track a particular person and the Kalman filter is applied to enhance the performance of this algorithm in case of occlusion, noise, and different light conditions. The experiments show that the combination of YOLOv4-tiny and the improved Camshift algorithm raises the standard of speed as well as robustness. The proposed algorithm is suitable for running in real time and adapts well to the same color and different light conditions

Oxidation of l-leucine amino acid initiated by hydroxyl radical: are transition metal ions an enhancement factor?

Hydroxyl radical (HO·) formation initiated by the Fenton-type reactions of Fe and Cu complexes of l-leucine (Leu) amino acid as well as its oxidation reaction by HO· was computationally investigated by using the density functional theory method at the M05-2X/6-311++G(3df,2pd)//M05-2X/6-311++G(d,p) level of theory in the aqueous phase. The results showed that dipole-salt is the main form of Leu in the physiological condition. Leu exhibits high chelating potential towards both Fe(III)/Fe(II) and Cu(II)/Cu(I) ions with the most favourable coordinating positions at two oxygen atoms of the –COO functional group. Furthermore, the Leu-ions complexes show a high risk of HO· formation via Fenton-like reactions, especially when ascorbate anion exists in the environment as a reducing agent. Finally, the oxidation reaction of l-leucine by HO· demonstrated a relatively high overall apparent reaction rate, koverall, being 1.18 × 109 M−1 s−1, in which formal hydrogen transfer reactions of the dipole-salt form occur as the primary mechanism. Consequently, the Leu oxidation by HO· radical can be promoted by the Fenton reaction enhancement of its transition metal complexes

Interaction Behaviors and SERS Spectra of Chlorpyrifos Insecticide Adsorbed on Silver Nanoparticles

International audienc

Interaction Behaviors and SERS Spectra of Chlorpyrifos Insecticide Adsorbed on Silver Nanoparticles

International audienc