A weighted residual relationship for the contact problem with Coulomb friction

International audienceIn this work, a weighted residual relationship is proposed as an extension of the standard virtual work principle to deal with the large deformation contact problem with Coulomb friction. This weak form is a mixed relationship involving the displacements and the multipliers defined on the reference contact surface of the contactor and is shown to be equivalent to the strong form of the initial/boundary value contact problem. The discretization in space by means of the finite element method is carried out on the mixed relationship in a simple way in order to obtain the semi-discrete equation system. The contact tangent stiffness is derived and numerical examples are presented to assess the efficiency of the formulation. (c) 2009 Elsevier Ltd. All rights reserved

Factors Influence Organic Food Purchase Intention of Vietnamese Consumers

The research focuses on examining factors influencing the organic food purchase intention of Vietnamese consumers. The organic food market has been developing steadily and growing in popularity, but the factors affecting organic food purchase intention are not well-studied. A conceptual model of factors was created based on evaluating other conceptual models from global research. The conceptual model includes 8 independent variables: Health consciousness (HC), Environmental concern (EC), Personal attitude (PA); Subjective norms (SN); Perceived behavior control (PBC); Food price (FP); Food availability (FA); Transparent information (TI) which affect the dependent variable “Organic food purchase intention” (OFPI). A survey was conducted and received responses from 528 Vietnamese consumers; the data collected was analyzed by SMARTPLS to examine the factors and determine the impact of each factor. The results depict that factors affecting organic food purchases include Perceived behavior control (PBC); Transparent information (TI); Subjective norms (SN); and Food availability (FA) with a decreasing level of influence. The other factors such as Food price (FP); Environmental concern (EC); Health consciousness (HC), and Personal attitude (PA) don’t possess enough statistical significance to conclude. With the results, exchanges and discussions to enhance the organic food market are drawn

Study on the antioxidant capacity of Hibiscus rosa-sinensis decoction in vivo in Mus musculus var. albino

This study proved that Hibiscus rosa-sinensis has the antioxidant activity and the ability to recover liver functions when it was coordinated with cyclophosphamide in mice mode

Numerical modelling of moisture motion in heterogeneous soils using 1D-MIRBF method

In the present paper, we develop an efficient and accurate numerical approach based on one-dimensional-moving integrated radial basis function (1D-MIRBF) and fully implicit modified Picard method for simulating fluid movement in heterogeneous soils governed by the highly non-linear Richards equation. The major advantages of the proposed 1D-MIRBF method include (i) a banded sparse system matrix that helps reduce the computational cost; (ii) the Kronecker Delta property of the constructed shape functions, which helps impose the essential boundary conditions in an exact manner; and (iii) high accuracy and fast convergence rate owing to the use of the IRBF approximation. The performance of the present method is demonstrated through several 1--D and 2--D soil infiltration problems. Numerical results obtained are in agreement with other published results in the literature. This solver for moisture motion in soils will be incorporated into a surface-water-flow solver to handle the surface irrigation problem

Une formulation variationnelle du problème de contact avec frottement de Coulomb

International audienceA variational relationship is proposed as the weak form of the large deformation contact problem with Coulomb friction. It is a mixed relationship involving both the displacements and the multipliers; the weighting functions are the virtual displacements and the virtual multipliers. It is shown that the proposed weak form is equivalent to the strong form of the initial/boundary value contact problem and the multipliers are equal to the contact tractions.Dans ce travail, on propose une formulation variationnelle du problème de contact en grandes transformations avec frottement de Coulomb. Il s'agit d'une formulation mixte où les champs inconnus sont à la fois le champ des déplacements et le champ des multiplicateurs, et où les fonctions poids sont le champ des déplacements virtuels et le champ des multiplicateurs virtuels. On montre que le problème faible proposé équivaut bien au problème fort de contact et que les multiplicateurs sont égaux aux contraintes de contact

A simple weak form for contact problems with Coulomb friction

This paper proposes a weak form for the contact problem with Coulomb friction, written as extension of the standard virtual work principle and involving both the displacements and the multipliers defined on the reference contact surface. The mixed relationship is shown to be equivalent to the strong form of the initial/boundary value contact problem, and it can be discretized by means of the finite element method in a simple way. Typical numerical examples are given to assess the efficiency of the formulation in statics and dynamics

PERCEPTIONS OF ENGLISH-MAJORED STUDENTS IN THE HIGH-QUALITY PROGRAM AT CAN THO UNIVERSITY TOWARD LEARNING ENGLISH THROUGH WATCHING MOVIES

This descriptive study aims to answer three main research questions, namely 1) What are the perceptions of English-majored students regarding the impact of watching English movies on their learning motivation?, 2) What are their perceptions of the impact of watching English movies on their language development?, and 3) What challenges do the students encounter when learning English through watching movies? In order to address these key questions, the data collected from 175 freshmen and juniors majoring in English Studies of the High-Quality Program at Can Tho University through a 5-point Likert scale questionnaire were quantitatively analyzed. The statistical analysis of the gathered data revealed that all the study participants strongly agreed with the positive impacts of watching English movies on their motivations to learn the target language as well as on their language development. Despite these positive effects, the students also admitted that they inevitably encountered several challenges while learning English through movie-watching, particularly in terms of rapid speech, extensive use of slang, and figurative language in English movies. Based on these research outcomes, possible implications have been further discussed for the effective use of movies in EFL classrooms to support the students’ learning process.  Article visualizations

Multiobjective Logistics Optimization for Automated ATM Cash Replenishment Process

In the digital transformation era, integrating digital technology into every aspect of banking operations improves process automation, cost efficiency, and service level improvement. Although logistics for ATM cash is a crucial task that impacts operating costs and consumer satisfaction, there has been little effort to enhance it. Specifically, in Vietnam, with a market of more than 20,000 ATMs nationally, research and technological solutions that can resolve this issue remain scarce. In this paper, we generalized the vehicle routing problem for ATM cash replenishment, suggested a mathematical model and then offered a tool to evaluate various situations. When being evaluated on the simulated dataset, our proposed model and method produced encouraging results with the benefits of cutting ATM cash operating costs

Education and the livelihood of households in the Northwest Region, Vietnam

Using the updated data from the 2016 Vietnam Household Living Standard Survey, this study examines the role of education in the livelihood of households in the Northwest Region, the poorest region in Vietnam. Our micro-econometric analysis shows that education has a positive effect on choosing better livelihoods, on household income and poverty reduction, even after controlling for all other factors in the models. However, our quantile regression analysis reveals that the returns on education are substantially heterogeneous across percentiles of income distribution and tend to be higher for better-off households. This implies that education has an increasing effect on within-level income inequality. The finding suggests that a conventional approach employing only mean regression to study the effect of education on income could miss heterogeneity of interest to policymakers

Predicting water allocation trade prices using a hybrid Artificial Neural Network-Bayesian modelling approach

This paper proposes an integrated (hybrid) Artificial Neural Network-Bayesian (ANN-B) modelling approach to improve the accuracy of predicting seasonal water allocation prices in Australia’s Murry Irrigation Area, which is part of one of the world’s largest interconnected water markets. Three models (basic, intermediate and full), accommodating different levels of data availability, were considered. Data were analyzed using both ANN and hybrid ANN-B approaches. Using the ANN-B modelling approach, which can simulate complex and non-linear processes, water allocation prices were predicted with a high degree of accuracy (RBASIC = 0.93, RINTER. = 0.96 and RFULL = 0.99); this was a higher level of accuracy than realized using ANN. This approach can potentially be integrated with online data systems to predict water allocation prices, enable better water allocation trade decisions, and improve the productivity and profitability of irrigated agriculture