CORROSION INHIBITION PERFOMANCE OF FOUR NATURAL THIAZOLE DERIVATIVES: QUANTUM CHEMICAL AND MONTE CARLO SIMULATION STUDIE

Some thiazole derivatives: 2-acetyl-thiazole, 2-isobutyl-thiazole, 4-methyl-5-(2-hydroxyethyl)-thiazole, 2,4,5-trimethyl-thiazole used as corrosion inhibitors for iron were calculated at DFT-PBEPBE/6-31+G(d,p) level of theory and by Monte Carlo simulations. Quantum chemical parameters such as EHOMO, ELUMO, and HOMO and LUMO energy gap, chemical potential (m), electronegativity (c), global hardness (h), softness (S), dipole moment and electrophilicity index (w) have been calculated and discussed in detail to evaluate their inhibiting effectiveness. Mulliken-charges distribution and Fukui function were also calculated in order to visualize the reactive sites of the inhibitor molecules. Calculated results show that 2-acetyl-thiazole represents as the most efficient corrosion inhibitor. The –C4=C5– atomic center of thiazole ring demonstrates as the adsorption site in reaction with metallic surface. Corrosion inhibition effectiveness can be classified in decreasing order: ATZ TMTZ » SFR ISTZ.  Adsorption energies and interaction configurations of the four thiazole derivatives on Fe (110) were obtained using the Monte Carlo simulations. The results indicate that sulphur and nitrogen atoms as well as π-electronic systems within the thiazole ring aided the interaction between the inhibitor molecules and the Fe surface. All the four thiazole molecules adsorbed in parallel orientations on Fe (110) surface which ensures strong interactions with Fe. The adsorption energies were in accord with the results obtained using quantum chemical calculations.

The Organizational Structure of the Securities Company Under the Law of Vietnam Current

Purpose: The article researches on the organizational structure of securities company under the Securities Law 2019 in order to point out some limitations and shortcomings and propose for recommendations to improve law about organizational structure on this form of company.   Theoretical framework: Recent literature points out that securities companies play very important role in the development of Vietnam's stock market. However, in the current stage of development, from the influence and impact of international integration and the increasingly fierce competitive pressure, the securities companies have encountered many difficulties to survive. In there, limits and problems in regulations about securities company organizational structures has caused many difficulties for these companies when organization and operation. On the other hand, in the context of judicial reform in Vietnam, the issue of complete law system and expanding the freedom to business has always been paid special attention by the Party and Vietnam State.   Design/methodology/approach: The authors have combined traditional research methods of legal science such as legal analysis method, legal efficiency assessment method and legal comparison method.   Findings: According to research, regulations on the organizational structure of a securities company are directly related to the efficiency of management and administration of this company. In there, Supervisory Board/Internal Audit Committee always ensuring to limit negative and fraudulent acts of the company’s leaders, to better ensure the legitimate rights and interests of the company's members and customers. Therefore, the authors have proposed several solutions such as the need to stipulate the mandatory requirement of a Supervisory Board for the securities trading company under the model of limited liability company, and expand and strengthen the powers of the Supervisory Board/Internal Audit Committee, independent members in securities companies doing business in the form of joint stock company. These are important bases to contribute to perfecting the Law on the organizational structure of securities companies in Vietnam and further enhancing the stability and safety of the Vietnamese stock market.   Research, Practical & Social implications: This research may support many develop future research in Vietnam. At the same time, the research to help foreign investors' activities in Vietnam's stock market.   Originality/value: The research of the freedom to business and organizational structure of securities companies become more and more urgent and very important in Vietnam

A Model of Organizational Culture for Enhancing Organizational Commitment in Telecom Industry: Evidence from Vietnam

The aim of this study is to investigate the influence of organizational culture on organizational commitment in the context of the Vietnam telecom industry. The model was tested with a sample of 324 employees working for telecom companies. The result from the partial least squares method (PLS) using SmartPLS 3.0 program revealed a good fit between collected data and measurement scales which were introduced and developed in the Western contexts. Besides, the findings showed that the six dimensions of organizational culture had positive impacts on organizational commitment decreasingly: innovativeness, teamwork, training and development, reward and recognition, organizational communication, empowerment. This discovery highlighted the importance of organizational culture in enhancing employee commitment towards the organization as well as calls the management attention to these dimensions and long-term development policies

Energy-Efficient Design for Downlink Cloud Radio Access Networks

This work aims to maximize the energy efficiency of a downlink cloud radio access network (C-RAN), where data is transferred from a baseband unit in the core network to several remote radio heads via a set of edge routers over capacity-limited fronthaul links. The remote radio heads then send the received signals to their users via radio access links. We formulate a new mixed-integer nonlinear problem in which the ratio of network throughput and total power consumption is maximized. This challenging problem formulation includes practical constraints on routing, predefined minimum data rates, fronthaul capacity and maximum RRH transmit power. By employing the successive convex quadratic programming framework, an iterative algorithm is proposed with guaranteed convergence to a Fritz John solution of the formulated problem. Significantly, each iteration of the proposed algorithm solves only one simple convex program. Numerical examples with practical parameters confirm that the proposed joint optimization design markedly improves the C-RAN's energy efficiency compared to benchmark schemes.This work is supported in part by an ECR-HDR scholarship from The University of Newcastle, in part by the Australian Research Council Discovery Project grants DP170100939 and DP160101537, in part by Vietnam National Foundation for Science and Technology Development under grant number 101.02-2016.11 and in part by a startup fund from San Diego State University