Simulation of Event-Based Technique for Harmonic Failures

MAR

Influence of sulfate and chloride on the mechanical properties of fired clay masonry wall

This paper presents the influence of aggressive environment on the mechanical properties of masonry systems. The investigation involved the measurement of strength and modulus of elasticity of single leaf brick masonry wall which were built from fired clay bricks in conjunction with designation (iii) mortar with proportions of 1: 1: 6 (OPC: lime: sand). After being constructed, the specimens were cured under polythene sheet for 14 days in a controlled environment room with 80 ± 5% relative humidity and temperature of 25 ± 2ºC. The specimens were then exposed to the solution containing sodium sulfate and sodium chloride. The strength and modulus of elasticity of the brickworks were determined at the ages of 28, 56 and 180 days. The strength and modulus of elasticity of the brickworks, unbonded bricks, and mortar prisms were determined at the ages of 28, 56 and 180 days to quantify the contribution of bricks and mortar on the deformation of the masonry walls. As a result, fired clay brickwork is not durable and deteriorate in the environment containing sodium sulfate but durable in sodium chloride. The deterioration of the brickwork clearly influenced by the deterioration of mortar joint. The present of sodium chloride also retarding the attack of sodium sulphate

Authenticity testing and detection of Eurycoma longifolia in commercial herbal products using bar-high resolution melting analysis

The present study demonstrated High Resolution Melting (HRM) analysis combined with DNA barcode (Bar-HRM) as a fast and highly sensitive technique for detecting adulterants in Eurycoma longifolia commercial herbal products. Targeting the DNA barcoding of the chloroplastic region-ribulose biphosphate carboxylase large chain (rbcL) and the nuclear ribosomal region-internal transcribed spacer 2 (ITS2), PCR amplification and HRM analysis using saturated Eva green dye as the source of fluorescence signals, was accomplished by employing a real-time cycler. The results were further validated by sequencing to identify unknown sequence from Genbank database and to generate phylogenetic tree using neighbour joint (NJ) analysis. Both of the DNA markers exhibited a distinguishable melting temperature and shape of the normalised curve between the reference and the adulterants. In the case of species identification, ITS2 was more successful in differentiating between species. Additionally, detection of admixture sample containing small traces of targeted E. longifolia DNA (w/v) can be detected as low as 5% for rbcL and less than 1% for ITS2, proving the sensitivity and versatility of the HRM analysis. In conclusion, the Bar-HRM analysis is a fast and reliable technique that can effectively detect adulterants in herbal products. Therefore, this will be beneficial for regulatory agencies in order to regulate food safety issues

Effects of nano-palm oil fuel ash and nano-eggshell powder on concrete

Palm oil fuel ash (POFA) is a by-product from palm oil manufacturing and is currently disposed to open areas and landfills without treatment, thereby causing environment pollution. Grinding POFA to nanoparticles called NPOFA results in increased pozzolanic activity. Meanwhile, eggshells (ESs) are a biowaste from restaurants. They are disposed to landfills, thus generating undesirable gases and causing environmental damages. ES powder (ESP) has a large amount of calcium oxide, which is essential for hydration in concrete production. In this study, ESP was used to induce low calcium content in NPOFA. Cement was replaced with NPOFA at ratios of 0%, 10%, 20%, and 30% to produce green concrete, and the ESP proportions constituted 2.5% and 5% of the total binders. The curing ages were 7, 14, and 28 days. The results showed that NPOFA exhibited a significant improvement in strength of developed green concrete. ESP improved concrete durability by reducing water absorption. Therefore, this concrete may have high resistance to environmental attacks, such as those involving sulfates and acids

Histopathological and cholinesterase changes in the gills of Clarias gariepinus as a result of cadmium exposure

Aim : The cholinesterase (ChE) based inhibition and histopathological studies from fish were investigated and represented in this study to develop as one of the great potential biomarkers for heavy metals monitoring. Methodology : In this study, the histopathological study of gills were observed a under microscope. The capability of ChE extracted from the gills of Clarias gariepinus was assessed for declining Cd. ChE was purified through affinity chromatography and continued with the optimisation and inhibition study (IC50) of cholinesterase. Results : Histopathological study of gills was carried out and several changes such as aneurysm, necrosis and lamella fusion were noted. Purification fold obtained from purified enzyme was 1.15 with 30% a yield specific activity 20.726. The optimum temperature for purified AChE was 35°C along with acetylthiocholine iodide (ATC) as a preferable substrate that had the highest Vmax value of 0.5452 U mg'1 and the lowest Km value of 0.0311 mM. The optimum pH was observed to be 10 of Tris-HCl as a medium. Meanwhile, the IC50 of cadmium was 6.808 mg ľ with R2 value of 0.9532. Interpretation : The result of the study can be used as a tool for further developing a biomarker for the detection of heavy metals in aquatic ecosystems. In addition, the baseline data provided can also be used for designing a kit, which would give rapid and accurate result

2.45 GHz passive RFID tag antenna mounting on various platforms

This paper presents the design of a passive RFID tag antenna operating at 2.45 GHz. The electromagnetic simulation software called CST is used for design and simulation. A high gain (5.842dB), a good impedance matching with the microchip (-30.0 dB Return Loss) and a satisfactory read range performance (upto 5 m) was obtained. One approach of designing RFID tag is that the tag should be less sensitive to the various types of objects. The effects of obstacles on antenna’s characteristics have been investigated by placing the tag antenna against a metallic, rubber, glass and wood surfaces. Simulation results show slight variations which is within tolerance range. Key words: RFID, Tag Antenna, CS

The present state of the use of eggshell powder in concrete: a review

Eggshell (ES) is a bio-waste material obtained from bakers and fast-food restaurants. This waste material is generally disposed of in landfills, causing health hazards and polluting the environment. Eggshell powder (ESP) has high amounts of calcium and can be combined with pozzolanic materials, such as fly ash, which have low calcium content. This paper presents the results of the latest studies on the utilization of ESP as a filler, cement and fine aggregate. The chemical composition, physical properties and fresh and hardened properties of ESP concrete at different proportions are also presented. Results indicate the potential of using ESP with other pozzolanic materials to improve concrete properties and reduce cement production, thereby minimizing environmental pollution. The compressive, flexural and tensile strengths have also been improved with the use of some materials with ESP as cement replacement. However, some studies reported a reduction when cement is replaced with high percentages of ESP, particularly those larger than 10%. Furthermore, the modulus of elasticity decreases with high levels of replacement. The specific gravity of ESP was found to be lower than that of cement. The durability and water absorption of concrete were reduced with the addition of ESP

Optimising concrete containing palm oil clinker and palm oil fuel ash using response surface method

Cement production led to the consumption of high energy and generated harmful gases, such as CO2. Therefore, the use of alternative materials becomes necessary. The research attempts to use palm oil clinker (POC) and ultrafine palm oil fuel ash (UPOFA) as a full replacement of coarse aggregate and partial cement replacement, respectively. This study aims to use the response surface method (RSM) to optimise the properties of concrete, namely, density and water absorption. The study investigated the density and water absorption of concrete using RSM. Results showed that the density reduced sharply owing to the full replacement coarse aggregate by POC aggregate. Meanwhile, water absorption increased significantly due to the rise in the POC aggregate replacement. However, water absorption decreased because of the use of UPOFA as cement replacement. The study recommended the use of more UPOFA as cement replacement because of its high pozzolanic property

Sustainable use of palm oil fuel ash as a supplementary cementitious material: A comprehensive review

Cement concrete has been popularly used as a construction material with an approximate annual consumption of 10 billion tons. Increase in urbanization and industrialization increased the demand of concrete materials at recent days. It has been estimated that the cement industry alone generates approximately 6–7% of the total CO2 emissions. These environmental concerns demand the use of alternative renewable and sustainable materials to produce green concrete. Meanwhile, a large amount of agricultural waste, especially palm oil waste is disposed into the open area and landfills, causing serious environmental problems. An estimated 12 million tons of palm oil fuel ash (POFA) is generated in the world per annum. To minimize the passive effects of concrete production using traditional Portland cement, it was recommended by many researchers to adopt the palm oil waste fall-outs as a supplementary cementitious material. It may be considered a suitable and reliable source for better solutions to magnify the sustainability of the construction industry. This paper reviews the potential utilization of POFA as an alternative cementitious material in concrete. The impact of POFA on the fresh, hardened and durability properties of concrete are deliberated, providing a brief of the current knowing about a suitable utilization of POFA as SCM to promote a sustainable environment in the construction industry. The grinding treatment of raw POFA particles significantly enhances the quality of POFA in terms of compressive strength, resistance against aggressive environments and assist in reducing the drying shrinkage of concrete, although there is a tendency to increase the water absorption and delay the hydration heat of cement mortar. The high quantity of SiO2 in POFA enables pozzolanic reaction and delays the setting times with the addition of CaO to produce further C–S–H gels. The utilization of POFA (20%), ultrafine POFA and nano POFA (30%) can produce high strength and durable concrete, proving to be a promising contribution towards the sustainability of the construction industry

Compressive and flexural strength of concrete containing palm oil biomass clinker and polypropylene fibres

This paper presents the effects of using palm oil biomass (POB) clinker with polypropylene (PP) fibres in concrete on its compressive and flexural strength performances. Due to infrastructural development works, the use of concrete in the construction industry has been increased. Simultaneously, it raises the demand natural sand, which causes depletion of natural resources. While considering the environmental and economic benefits, the utilization of industrial waste by-products in concrete will be the alternative solution of the problem. Among the waste products, one of such waste by-product is the palm oil biomass clinker, which is a waste product from burning processes of palm oil fibres. Therefore, it is important to utilize palm oil biomass clinker as partial replacement of fine aggregates in concrete. Considering the facts, an experimental study was conducted to find out the potential usage of palm oil fibres in concrete. In this study, total 48 number of specimens were cast to evaluate the compressive and flexural strength performances. Polypropylene fibre was added in concrete at the rate of 0.2%, 0.4% and 0.6%, and sand was replaced at a constant rate of 10% with palm oil biomass clinker. The flexural strength of concrete was noticed in the range of 2.25 MPa and 2.29 MPa, whereas, the higher value of flexural strength was recorded with 0.4% polypropylene fibre addition. Hence, these results show that the strength performances of concrete containing POB clinker could be improved with the addition of polypropylene fibre