Md. Rezaur Rahman

Physico-Mechanical Properties of Jute Fiber Reinforced Polypropylene Composites:

Jute fiber reinforced polypropylene composites were manufactured using a single extruder and an injection molding machine. Raw jute fiber was oxidized and manufactured composites were post-treated with urea to increase the compatibility of the jute fiber with the polypropylene matrix. Both raw and oxidized jute fiber was utilized and four levels of fiber loading (20, 25, 30, and 35 wt%) was used during composite manufacturing. Microstructural analysis (scanning electron microscopy) and mechanical tests (tensile, flexural, impact, hardness, and water absorption) were conducted. Post-treated jute fiber reinforced specimens yielded better mechanical properties compared to the oxidized and raw ones. Based on fiber loading, 30% fiber reinforced composites had the optimum set of mechanical properties. Authors propose that the bonding between the polypropylene matrix and urea treated jute fiber must be increased in order to have improved mechanical properties at higher fiber content.

Influence of Fiber Treatment on the Mechanical and Morphological Properties of Sawdust Reinforced Polypropylene Composites

In the present work, sawdust reinforced polypropylene composites were fabricated using an extruder and an injection molding machine. Raw sawdust was chemically treated with benzene diazonium salt in order to improve the mechanical properties of the composites. The effect of the chemically treated sawdust reinforced PP composites was evaluated from their mechanical and surface morphological properties. The values of the mechanical properties of the chemically treated sawdust–PP composites were found to be significantly higher than those of the raw ones. Water uptake tests revealed that composites prepared from the chemically treated sawdust absorb lower amount of water compared to the ones prepared from raw sawdust, suggesting that hydrophilic nature of the cellulose in the sawdust has significantly decreased upon chemical treatment. The surface morphology obtained from scanning electron microscopy (SEM) showed that raw sawdust–PP composites possess surface roughness with extruded filler moieties, and weak interfacial adhesion between the matrix and the filler while the chemically treated one showed improved filler–matrix interaction. This indicates that better dispersion of the filler with the PP matrix has occurred upon chemical treatment of the filler.

Models for Cyclone Shelter Planning in Bangladesh

ABSTRACT The coastal areas of Bangladesh are prone to disaster due to storm surge floods generated by tropical cyclones which form in the Bay of Bengal. A master plan, prepared at the request of the Government of Bangladesh, estimated that 2,500 new cyclone shelters are needed to provide adequate protection for the projected population in the year 2002. Since this will require an investment of 300 million USD (12 billion Bangladeshi Taka) which may not be possible in the near future, a means of identifying priority areas is needed. To this end, a mathematical programming model is developed. The model relies on input from hydrologic simulation models which determine the spatial distribution of flood depth, as well as from surveys and an infrastructure inventory which provide an estimate of population vulnerability. Using the mathematical programming model, a multi-objective analysis is conducted to explore some trade-offs involved in allocating shelters among a number of planning units. Results indicate th...

Review on the Risk Assessment of Heavy Metals in Malaysian Clams.

The current review discusses the levels of six heavy metals in different clam species from 34 sites of Malaysian coasts. The concentrations (µg/g dry weight) of these heavy metals ranged around 0.18–8.51, 0.13–17.20, 2.17–7.80, 0.84–36.00, 24.13–368.00, and 177.82–1912.00 for Cd, Pb, Ni, Cu, Zn, and Fe, respectively. It was observed that the concentrations of metals slightly depend on different clam species but mostly depend on site locations. According to Malaysian Food Regulation (1985), about 30% and more than 50% sites are safe from Cd and Pb contamination, respectively, and also the clam species from the other populations studied were safe for consumption.

Synthesis and Characterization of Cellulose from Green Bamboo by Chemical Treatment with Mechanical Process

Bamboo cellulose was prepared by chemical process involving dewaxing, delignification, and mercerization process. Four samples namely, green bamboo fiber (GBF), dewaxed bamboo fiber (DBF), delignified bamboo fiber (DLBF), and cellulose fiber (CF) had been analysed. FTIR and TGA analysis confirmed the removal of hemicellulose and lignin at the end stage of the process. FTIR results reveal that the D-cellulose OH group occurred at 1639 cm−1 region. SEM micrograph showed that mercerization leads to fibrillation and breakage of the fiber into smaller pieces which promote the effective surface area available for contact. Barrer, Joiyner, and Halenda (BJH) method confirmed that the effective surface area of CF is two times larger compared to GBF. CF showed the highest activation energy compared to GBF. It indicates that CF was thermally stable.

Effect of fiber treatment and nanoclay on the tensile properties of jute fiber reinforced polyethylene/clay nanocomposites

The tensile properties of chemically treated jute fiber reinforced polyethylene/clay nanocomposites were investigated. Nanocomposites were prepared using hot press moulding technique by varying jute fiber loading (5, 10, 15 and 20 wt%) for both treated and untreated fibers. Raw jute fibers were chemically treated with benzene diazonium salt to increase their compatibility with the polyethylene matrix. Physical and mechanical properties were subsequently characterized. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis was utilized to study physical properties. Tensile test was conducted for mechanical characterization. FTIR and SEM study showed interfacial interaction among jute fiber, polyethylene and nanoclay. It was observed that at optimum fiber content (15 wt%), treated composites exhibited improvements in tensile strength and modulus by approximately 20 % and 37 % respectively over the raw ones. On the other hand, this composite exhibited improvements in tensile strength and modulus by approximately 8 % and 15 % respectively over the composites without nanoclay. However, treated jute fiber reinforced composites showed better tensile properties compared with untreated ones and also nanoclay incorporated composites enhanced higher tensile properties compared without nanoclay ones.

Cadmium and Lead in Blood Cockle (Anadara granosa) from Asajaya, Sarawak, Malaysia

The concentrations were ranged from 1.35 ± 0.16 to 2.22 ± 0.34 µg/g (dry weight) and 2.65 ± 0.34 to 4.36 ± 0.53 µg/g (dry weight) for Cd and Pb, respectively, in blood cockle Anadara granosa from four sites of Sabang River, namely, Kampung Sambir, Kampung Tambirat, Beliong Temple, and Kampung Tanjung Apong, which are located at Asajaya, Sarawak, Malaysia. All values exceeded safety limits set by Malaysian Food Regulation (1985). It may be the cause of serious human health problems after long term consumption. Thus, consumer should have consciousness about such type of seafood from mentioned sites and need further investigation.

A-class: A classroom software with the support for diversity in aptitudes of autistic children

The burgeoning growth of the e-Learning technologies implies the fact that the future education system will largely depend upon the electronic devices and computer aided technologies. It has already been proved that the computer aided teaching techniques are much more effective for the children than the traditional teaching system in most of the cases. A large number of software has been designed to assist the teachers in the classroom to teach and evaluate the students. Although those software systems are good enough for a class with normal (neurotypical) children, those very often fail to address the special needs of the autistic children. Hence, the autistic children face various challenges in participating with neurotypicals in the same classroom. We have addressed this problem by designing and implementing an intelligent classroom software, named “A-Class”, which takes care of the diversity of tastes among the autistic children of a classroom and helps the teacher to teach in a class participated by both autistic and neurotypical children. In this paper we discuss the idea, design and implementation of A-Class based upon our five months of intervention with the autistic children at Autism Welfare Foundation (AWF) in Dhaka.

Influence of Alkali Treatment on the Surface Area of Aluminium Dross

Aluminium dross is an industrial waste from aluminium refining industry and classified as toxic substances. However, the disposal of dross as a waste is a burden to aluminium manufacturer industries due to its negative effects to the ecosystem, surface, and ground water. Therefore the purpose of this study is to evaluate the influence of sodium hydroxide (NaOH) on the surface area and pore size of aluminium dross. There were 3 stages in the treatment activities, which were leaching, precipitation, and calcination process. The optimum result from this study was the surface area of aluminium dross increases from 10.1 m2/g up to 80.0 m2/g at 40°C, 1% NaOH, and 15-minute reaction time. Thus, aluminium dross has a potential to be converted into other useful material such as catalyst and absorbent. The benefit of this research is that the hazardous industrial waste can be turned into wealth to be used in other applications such as in catalytic activities and absorber in waste water treatment. Further investigation on the physicochemical of aluminium dross with different acid or alkali should be conducted to get deeper understanding on the aluminium dross as a catalyst-type material.

Thermal Stability and Decay Resistance Properties of Tropical Wood Polymer Nanocomposites (WPNC)

The effects of nanoclay on the thermal stability and decay resistance properties of tropical wood polymer nanocomposites (WPNCs) were investigated in this work. WPNC were prepared from several selected tropical wood species by impregnating the selected woods with a combination of nanoclay and phenol formaldehyde (PF) prepolymer mixture. The formation of WPNC was confirmed by the fourier transform infrared spectroscopy (FTIR) analysis. Thermal property of manufactured WPNC in terms of thermogravimetric analysis (TGA) was evaluated, and an improvement in thermal stability was found for fabricated WPNC. The wood was then exposed to two types of fungi; white-rot (polyporous versicolor) and brown-rot (postia placenta), for 12 weeks. Decay was assessed through percentage (%) of weight loss. A significant improvement was found in the treated woods compared to the untreated ones. In addition, the fabricated WPNC showed lower moisture content compared with raw one.