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Test development involves many required stages, including examining the psychometric characteristics of the test and each test item. This study describes the development of an English vocabulary test designed for EFL learners in Vietnam and provides an analysis using the Rasch model to evaluate the test quality and test items. The data was collected from 202 students from a Vietnamese university and analysed with the use of the Conquest computer program. The results show that the test had high reliability. Four out of 50 items were removed from the test as not fitting the Rasch model. 36 items were ranked very good, and 10 items require some revision efforts for better distractors. The paper is expected to contribute to the wide application of the Rasch model in the practices of test development and suggest the development of more reliable instruments for EFL learners to assess their vocabulary.

This research aims to guide teachers in designing and conducting science lessons for junior high school students. The 5E model was revised to create a five-step teaching procedure suitable to natural science characteristics. The lesson plans contain learning activities and assessment tools to measure students’ learning outcomes based on science competence criteria that students need to develop. A sample project of the Sixth Grade curriculum was planned and conducted in three classes with more than one hundred students. The qualitative (interview) and quantitative data (marks) collected after the experiments showed the interest and concentration of students in the lessons. Moreover, the data also proved the reliability and validity of assessment tools used in each 5E activity to assess students’ science competence. The results indicated the effectiveness of the 5E model in helping students practice and nurture competence in teaching natural science.

Fused Deposition Modeling (FDM) 3D printing is one of the most popular 3D printing technology today and its products is always interested to improving their mechanical properties by printed engineering parameters. In this study, the influences of infill density and printing pattern on mechanical properties of FDM 3D printing structure have been studied on some common printing materials including Acrylonitrile Butadiene Styrene (ABS), Polylactic Acid (PLA), carbon fibre reinforced PLA composites (PLA-CF). Each material is printed with different patterns such as hexagonal, square, triangular, zigzag structures at 15% infill. Particularly for the triangle printed structure of ABS, there are three infill densities at 15 %, 25 % and 40 %. The experimental process has evaluated the strength and deformation of the printing patterns. The results have shown that the influence of printing patterns on compressive strength are significant because of the relationship between printing patterns and sample weight. Besides, infill density also have a great influence on the compressive strength of 3D printed products.

In this work, commercial Viscose (cellulosic based precursor) rayon-based carbon fibers were oxidized to make activated carbon fibers (ACFs). Carbon fibers were made from Viscose fibers in carbonization process at 1200°C. The ultimate carbon fibers possessed carbon content above 94 mass% and fiber dimension about 8 mm. These fibers were activated to make ACFs by oxidizing gas such as steam of carbon dioxide. The experiments were conducted at temperature ranged from 800°C to 900°C with carbonic steam’s flow of 3 l.min-1. The vaporous benzene adsorbability of activated carbon fibers was then measured by Mark Bell method. The adsorbability (a) and specific surface area (ABET) of ACFs were determined. The properties of the produced ACFs were investigated and analyzed by SEM and TEM imaging. The results showed that obtained fibers have maximum benzene adsorbability of 4.58 mmol.g-1 and BET surface area reached 1357 m2.g-1. These activated carbon fibers were able to use for toxic chemical prevention equipment.

Bulk moulding compounds (BMCs) are composite materials of thermosetting polymer matrix reinforced by short glass fibers. BMCs have known as the alternative of the traditional materials thanks to their optimal properties such as lightweight, durability, corrosion under certain environment, formable, high electrical resistance... The previous study mentioned the process of manufacturing composite materials BMCs from unsaturated polyester resin reinforced with short glass fiber and CaCO3 filler by Z axis mixer and applying in the circuit breaker bottom, [1, 2]. To improve the thermal resistance of BMCs under high temperature condition in the industry, in this research, alumina filler was added to investigate the influence of alumina with the different content of 15wt.% and 20wt.% on the mechanical, thermal and electrical properties of BMCs. Specimens manufactured with and without alumina filler content were compared. The results show clearly that adding alumina could improve the thermal properties whereas this might decrease the tensile strength of BMCs. The experimental results also indicated the influence of mass fraction of alumina filler content on properties of BMCs.

In this work, commercial Viscose fibers (cellulosic based precursor) were used for making carbon fibers. The experimental procedures include two main steps: Stabilization in air atmosphere and Carbonization in inert gas atmosphere. In the first step, the Viscose fibers are stabilized with the catalyst of mixture urea/diamonium hydrogen phosphate in air at temperature of 250 °C. The stabilized fibers are then carbonized in argon at heating rates of 3 °C.min-1 (below 600 °C) and 5 °C.min-1 (above 600 °C). Ultimate carbonization temperature is 1200 °C. Commercial Viscose fibers possessed carbon content about 40 wt% and fiber dimension is approximately 18 μm. After carbonization, obtained fibers have carbon content above 94 wt% and diameter of about 8μm. The Thermogravimetry Analysis (TGA), Carbon analysis, SEM imaging and XRD analysis are used for this study.

In this paper, selective laser sintering (SLS) was applied to join two materials by printing Ti–6Al–4V powder on a Ti substrate without any support parts. The characteristics of the interface between the as-built Ti–6Al–4V sample and the substrate were investigated. The analysis indicates that a heat-affected zone (HAZ) and the fish-scale type were formed at the joining area. The combination of smaller grains, acicular [Formula: see text] martensite, and lamellar [Formula: see text] structures was observed inside the interface zone. The hardness value at the interface area was measured by about 320 HV which is higher than 280 HV of the substrate and smaller than 369 HV of the as-built sample. The results predict that the SLS process is a promising method for manufacturing of hybrid materials.

Bulk Moulding Compounds (BMC’s) are short fibre reinforced polymer composites that behave, during their forming, as concentrated fibre suspensions. Their suspending fluid is also a concentrated granular suspension made up of the polymer filled with mineral fillers. In this work, a method is proposed to model their flow. Firstly, the rheology of an industrial BMC was analysed by performing two types of mechanical tests, i.e. lubricated simple and plane strain compression experiments. Experimental results underline the roles of the current strain, the strain rate as well as the mechanical loading on the rheology of the BMC. Secondly, a 3D tensorial rheological model is proposed to reproduce the simple and plane strain compression experiments. Then this model is implemented into a Finite Element code dedicated to the simulation of compression moulding. Simulation results are finally compared with experiments achieved with rather complex flow situations.

International audience; X-ray microtomographs of samples cut from non-deformed and compression moulded Sheet Moulding Compounds (SMC) plates have been analysed using the phase contrast mode. Results emphasise a significant decrease of the porosity after moulding, this phenomenon being enhanced with increasing the initial SMC temperature. They also show that pronounced migration of the polymer-matrix occurs through the thickness of the plates during compression moulding. The substructures of compression moulded plates through their thickness exhibit a core zone sandwiched between upper and lower skins. Inside the skins, the fibre content and the porosity are weaker than in core zones, and fibre-bundles are highly broken up. On the contrary, fibre-bundles remain preserved in core zones. Therein, the significant flattening and widening of bundles, their weak bending as well as their orientation have been quantified.

BACKGROUND: WHO recommends screening for TB and evaluation for isoniazid preventive therapy (IPT) based on evidence that they reduce TB-related morbidity and mortality among HIV-infected persons. In Vietnam an IPT pilot was implemented in two provinces; TB screening treatment and outcomes were evaluated to inform the adoption and scale-up of IPT. METHODS: During April 2008 to March 2010 eligible HIV-infected persons aged >15 years with no previous or current TB treatment alcohol abuse or liver disease were screened for TB. If TB disease was ruled out based on symptoms chest x-rays and sputum smears isoniazid was administered for 9 months. RESULTS: Among 1281 HIV-infected persons who received initial eligibility screening 520 were referred to and evaluated at district TB clinics for TB disease or IPT eligibility. Active TB was diagnosed in 17 patients and all were started on treatment. Of 520 patients evaluated 416 (80.0%) initiated IPT: 382 (91.8%) completed IPT 17 (4.1%) stopped treatment 8 (1.9%) died 3 (0.7%) developed TB during IPT and 6 (1.4%) had unknown outcomes. No severe adverse events were reported. CONCLUSIONS: IPT treatment completion was high; no serious complications occurred. Improving and expanding intensified case-finding and IPT should be considered in Vietnam. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Background An estimated 120,000 HIV-associated cryptococcal meningitis (CM) cases occur each year in South and Southeast Asia; early treatment may improve outcomes. The World Health Organization (WHO) recently recommended screening HIV-infected adults with CD4

Bulk moulding compounds (BMCs) are thermoset polymer composites widely used in electric and automotive industries. During their processing by injection, BMCs look like fibre-reinforced granular suspensions in the form of pastes, the rheology of which is not well known. For that purpose, lubricated compression tests were performed on BMC samples with various formulations. Firstly, results show that samples flow without sticking to the rheometer’s plates, validating the efficiency of the lubricant. A correction, which requires few assumptions on the rheology of BMC, is then proposed to account for its contribution to the overall axial stress. Thereby, the influences of the axial strain rate, the loading path, the polydispersity of the mineral filler and the fibre content on the BMC flow are analysed. A 1D elementary non-linear viscoelastic model is proposed to capture the main observed trends.