ECONOMIC ANALYSIS OF ASEAN FREE TRADE AREA; BY A COUNTRY PANEL DATA

This paper is an attempt to use the Hausman-Taylor (HT) estimation to examine the determinants of trade flows of Asean Free Trade Area (AFTA). Based on the two-way error component form of the gravity model, we employ the HT technique to estimate export flows by a country panel data of 39 countries for the period 1988-2002. The estimations have shown the following important results. Firstly, export flows among two countries increase more proportionately with GDPs. More interestingly, trade is higher between countries of identical preferences than those of different ones. Secondly, the most crucial result is that AFTA has only produced the trade creation among its members. Finally, this study suggests the importance of trade facilitation policy to support the targets of FTA.AFTA, gravity models, panel data, trade.

Size dependent of the effective conductivity of composite with imperfect interfaces

Based on the circle assemblage model, the effective properties of the inclusion with imperfect interface are derived. The equivalent inclusion is incorporated in the Fourier Transform algorithm to determine the effective conductivity of the composite with lowly conducting or highly conducting interface. The size effect is considered for both cases. Numerical results are provided to illustrate the dependence of the effective conductivity on the size of inhomogeneities

The Power of Qualitative Research: Cultivating Autoethnography for Personal Awakening, Humanity, and Transformation

This article is an autoethnography of how engaging with my previous autoethnographic article facilitated my recovery and self-growth. I wrote my previous piece (Nguyen-Trung, 2022) while stranded in Australia due to the COVID-19 pandemic, which prevented me from visiting my grandfather one last time before his passing in 2021. If my past autoethnography focused on the themes of death, grief, and loss, the current article’s autoethnography revolves around awakening, healing, and self-transformation. In this current article, I reflexively look back on my autoethnographic journey and reflect on how it impacted me as a grandchild and a human being on the one hand, and a qualitative sociologist and a writer on the other. I tell stories of how, since writing my first autoethnography and sharing it with others, whether at an academic conference, a meeting, a social encounter, or via a social media post, I managed to overcome the darkest time of my life and gradually heal my personal crisis and somehow transform myself. There were three key lessons learned from such a journey: the emergence of self-awareness, the significance of empathy and humanity within research communities, and the therapeutic and transformative potential of writing

Appropriate sample size and effects of microscopic parameters on the shear strength and strain localisation of 2D cohesive-frictional granular assemblies

Granular materials are made up of smaller particles, manifestation of microstructure results in a macroscopic response of granular material. Understanding the overall mechanical behaviour from microscopic parameters is one of the main challenges in many engineering fields including civil engineering. When modelling this kind of material by Discrete Element Model (DEM) using idealized circular grains, the effects of appropriate sample size and microscopic parameter changes have been a crucial subject. Previous research has primarily relied on the case of purely frictional granular materials. In this paper, we use DEM to investigate the appropriate sample size and the relationship between microscopic parameters and the macroscopic responses of cohesive-frictional granular assemblies by performing a series of biaxial tests. Our findings indicate that a minimum number of particles is required to balance between mechanical behaviour and computing time. In addition, through extensive parametric studies, the paper explores the impact of factors such as interparticle bonds, intergranular friction coefficients, and initial void index on the overall shear behaviour of granular assemblies. Also, the result reveals a strong correlation between shear band formation and the break field of cohesive contact (static variable) and the translations and rotations of grains (kinematic variable)

Appropriate sample size and effects of microscopic parameters on the shear strength and strain localisation of 2D cohesive-frictional granular assemblies

Granular materials are made up of smaller particles, manifestation of microstructure results in a macroscopic response of granular material. Understanding the overall mechanical behaviour from microscopic parameters is one of the main challenges in many engineering fields including civil engineering. When modelling this kind of material by Discrete Element Model (DEM) using idealized circular grains, the effects of appropriate sample size and microscopic parameter changes have been a crucial subject. Previous research has primarily relied on the case of purely frictional granular materials. In this paper, we use DEM to investigate the appropriate sample size and the relationship between microscopic parameters and the macroscopic responses of cohesive-frictional granular assemblies by performing a series of biaxial tests. Our findings indicate that a minimum number of particles is required to balance between mechanical behaviour and computing time. In addition, through extensive parametric studies, the paper explores the impact of factors such as interparticle bonds, intergranular friction coefficients, and initial void index on the overall shear behaviour of granular assemblies. Also, the result reveals a strong correlation between shear band formation and the break field of cohesive contact (static variable) and the translations and rotations of grains (kinematic variable)

DEM investigation on strain localization in a dense periodic granular assembly with high coordination number

Strain localization is one of key phenomena which have been studied extensively in geomaterials and for different kinds of materials including metals and polymers. This well-known phenomenon appears when structure/material is closed to failure. Theoretical, experimental, and numerical research have been dedicated to this subject for a long while. In the numerical aspects, strain localization inside the periodic granular assembly has not been well studied in the literature. In this paper, we investigate the occurrence and development of strain localization within a dense cohesive-frictional granular assembly with high coordination number under bi-periodic boundary conditions by Discrete Element Modeling (DEM). The granular assembly is composed of 2D circular disks and subjected to biaxial loading with constant lateral pressure. The results show that the formation of shear bands is of periodic type, consistent with the boundary conditions. This formation has the origins of the irreversible losing of cohesive contacts, viewed as micro-crackings which strongly concentrated in the periodic shear zones. This micromechanical feature is therefore strongly related to the strain localization observed at the sample scale. Finally, we also show that the strain localization is in perfect agreement with the sample’s displacement fluctuation fields

A new inverse trigonometric shear deformation theory for isotropic and functionally graded sandwich plates

A new inverse trigonometric shear deformation theory is proposed for the static, buckling and free vibration analyses of isotropic and functionally graded (FG) sandwich plates. It accounts for a inverse trigonometric distribution of transverse shear stress and satisfies the traction free boundary conditions. Equations of motion obtained here are solved for three types of FG plates: FG plates, sandwich plates with FG core and sandwich plates with FG faces. Closed-form solutions are obtained to predict the deflections, stresses, critical buckling loads and natural frequencies of simply supported plates. A good agreement between the obtained predictions and the available solutions of existing shear deformation theories is found to demonstrate the accuracy of the proposed theory