HO CHI MINH'S VIEW ON BUILDING A GOOD PARTY CELL

President Ho Chi Minh - the founder and trainer of the Communist Party of Vietnam to become a genuinely revolutionary party. Hence, Ho Chi Minh also became the leader of the Communist Party of Vietnam before being elected Party Chairman at the Second Congress of the Party in February 1951. In this article, the author studies two main contents in Ho Chi Minh's view on building a party cell. First, Ho Chi Minh's view of the role and tasks of the party cell. Second, Ho Chi Minh's view on building a good party cell.  Article visualizations

Near-microscale modelling of dry woven fabrics under in-plane shear loading

This article proposes a near micro-scale modelling technique to predict nonlinear shear behaviour of dry woven fabrics in a picture frame test using the digital element method. In the proposed model, the fabric yarns are modelled as bundles of virtual fibres that are then modelled by the truss elements in finite element code. Additionally, our finite element analysis was performed in a repeated unit cell and the contact friction among the fibres is explicitly considered. Especially, we proposed so-called enhanced periodic boundary conditions to capture the mechanical behaviour of fabrics both in the small and large shear angle regimes

Creating Fatigue Curve for Steel Machine Elements Using Fatigue Test Method with Gradually Increasing Stress Amplitude

In order to create a fatigue curve, the traditional fatigue test method is applied to specimens using a cyclic stress with constant amplitude. However, this method has disadvantages such as the experimental results could not be used because of specimens broken before reaching the expected stress amplitude, or the tests may be stopped before specimen broken because of limitation of time. To overcome this hurdle of the traditional method, a new experimental method using cyclic stress with gradually increasing amplitude was proposed to build the fatigue curve for steel machine elements

Mesoscale finite element analysis of cracked composite laminates under out-of-plane loads using 3D periodic boundary conditions

The behavior of composite materials under out-of-plane loads is strongly affected by the presence of transverse ply cracks. The cracks perturb the distribution of stresses leading to large out-of-plane shear stiffness reductions. It is crucial to include these effects in the damage material models to improve their accuracy. Therefore, the stress transfer and stiffness reduction in cracked laminates have been studied with a mesoscale finite element model (FEM) under general in-plane, out-of-plane normal and shear loads. A symmetric laminate containing ply cracks in a single orientation has been considered under the hypothesis of periodicity using a novel relaxed three-dimensional formulation of Periodic Boundary Conditions (PBCs). The local stresses have been verified versus different analytical and numerical methods. In addition, the degraded effective thermo-elastic constants involving out-of-plane properties have been calculated as a function of crack density. Both uniform and non-uniform distributions of cracks have been considered for different lay-ups including angle-ply and unbalanced laminates. The effect of contact between the crack surfaces has been studied for specific loading conditions. It is shown that a single formulation based on three-dimensional periodic boundary conditions is sufficient to determine the interfacial stresses and the complete thermo-elastic constants under in-plane and out-of-plane loads accurately

Vortex flow generator utilizing synthetic jets by diaphragm vibration

This paper develops a millimeter scale fully packaged device in which a vortex flow of high velocity is generated inside a chamber. Under the actuation by a lead zirconate titanate (PZT) diaphragm, a flow circulates with increasing velocity after each actuating circle to form a vortex in a cavity named as the vortex chamber. At each cycle, the vibration of the PZT diaphragm creates a small net air flow through a rectifying nozzle, generates a synthetic jet which propagates by a gradual circulation toward the vortex chamber and then backward the feedback chamber. The design of such device is firstly conducted by a numerical analysis whose results are considered as the base of our experimental set-up. A vortex flow generated in the votex chamber was observed by a high-speed camera. The present approach which was illustrated by both the simulation and experiment is potential in various applications related to the inertial sensing, fluidic amplifier and micro/nano particle trapping and mixing

Multiscale fatigue modelling of additively manufactured metallic components

Additively manufactured metallic components have been used in medical and aerospace applications. In these components, surface roughness and porosity are integral features that might significantly reduce their fatigue lives, especially in the high cycle fatigue regime. Thus, to precisely estimate the fatigue life of an additively manufactured component, these defective features are incorporated into our proposed fatigue model. To capture the local plasticity caused by the defects, a nonlinear isotropic-kinematic hardening elasto-plasticity model is employed in our finite element (FE) models. Additionally, the gas-entrapped pores are modeled as circles whilst the surface topography, which was measured using stylus-based profilometer, is explicitly mo deled in the FE models. The finite element results are post-processed by our in-house software to extract the Smith-Watson-Topper (SWT) fatigue indicator parameter. This parameter is calculated at each element centroid of the FE mesh, i.e., the local indicator. Afterward, an average value of the SWT parameter over a so-called critical area whose center is located at the considered centroid is also calculated, i.e., the nonlocal indicator. The results show that the local SWT indicator is too conservative in predicting the fatigue life of the componentwhile the nonlocal SWT one can provide good results

Estimation of methane emissions from local and crossbreed beef cattle in Daklak province of Vietnam

Objective: This study was aimed at evaluating effects of cattle breed resources and alternative mixed-feeding practices on meat productivity and emission intensities from household farming systems (HFS) in Daklak Province, Vietnam. Methods: Records from Local Yellow×Red Sindhi (Bos indicus; Lai Sind) and 1/2 Limousin, 1/2 Drought Master, and 1/2 Red Angus cattle during the growth (0 to 21 months) and fattening (22 to 25 months) periods were used to better understand variations on meat productivity and enteric methane emissions. Parameters were determined by the ruminant model. Four scenarios were developed: (HFS1) grazing from birth to slaughter on native grasses for approximately 10 h plus 1.5 kg dry matter/d (0.8% live weight [LW]) of a mixture of Guinea grass (19%), cassava (43%) powder, cotton (23%) seed, and rice (15%) straw; (HFS2) growth period fed with elephant grass (1% of LW) plus supplementation (1.5% of LW) of rice bran (36%), maize (33%), and cassava (31%) meals; and HFS3 and HFS4 computed elephant grass, but concentrate supplementation reaching 2% and 1% of LW, respectively. Results: Results show that compared to HFS1, emissions (72.3±0.96 kg CH 4 /animal/life; least squares means± standard error of the mean) were 15%, 6%, and 23% lower (p < 0.01) for the HFS2, HFS3, and HFS4, respectively. The predicted methane efficiencies (CO 2 eq) per kg of LW at slaughter (4.3±0.15), carcass weight (8.8±0.25 kg) and kg of edible protein (44.1±1.29) were also lower (p < 0.05) in the HFS4. In particular, irrespective of the HSF, feed supply and ratio changes had a more positive impact on emission intensities when crossbred 1/2 Red Angus cattle were fed than in their crossbred counterparts. Conclusion: Modest improvements on feeding practices and integrated modelling frameworks may offer potential trade-offs to respond to climate change in Vietnam