Journal of Engineering and Technological Sciences
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Microplastics Abundance and Uptake by Meretrix lyrata (Hard Clam) in Mangrove Forest
Get PDFThe aim of this study was to determine the abundance and distribution of microplastics in a mangrove ecosystem, while investigating its uptake by Meretrix lyrata. Microplastics were extracted from 10 L of mangrove sediment using a floatation method. Soft tissues of M. lyrata were digested and the microplastics were filtered and observed under a light microscope. Microplastics ranging from 21 µm to 100 µm were the most abundant in the mangrove layers at 936 ± 34 particles/kg (dry sediment) to 1,227 ± 55 particles/kg (dry sediment) (27.19% to 31.16% of the total quantity of recovered microplastics). The most abundant microplastics, with size from 5 µm to 1000 µm, were found in the deepest layer. M. lyrata accumulation of microplastics averaged at 0.35 ± 0.08 particles/g tissue and 0.23 ± 0.07 particles/g tissue (wet weight) before and after three-day depuration, respectively. Microplastics with size from 5 to 20 µm were the most commonly uptaken by the clams, averaging at 58% to 72% for pre-depuration and post-depuration, respectively. This study revealed that the most predominant size of microplastics in the sediment was 5 µm to 20 µm, which concurs with the results of the microplastics most commonly accumulated by M. lyrata. It is believed that microplastics accumulation in mangrove areas increases over time. On the other hand, the uptake rate of microplastics by Meretrix lyrata decreases over time, flushing microplastics from its system more frequently
Adsorption of Ethylene using Cobalt Oxide-Loaded Pillared Clay
Get PDFClay is an abundant material that is widely used as an adsorbent in pristine or pillared form. Pillared clays feature better properties, e.g. higher specific surface area, thus they can adsorb a higher quantity of adsorbates compared to pristine material. In this work, a preparation of pillared clay using Indonesian natural bentonite and its potential for ethylene removal are presented. The novelty is that a pillaring agent of cobalt (mixed with aluminum) was used, which not only served as a pillar but also as an active metal adsorbent for ethylene. Natural bentonite was pillared using Al (NO3)3.9H2O and Co (NO3)2.6H2O. The resulting material was then calcined at 250 °C. The final material was characterized by N2-sorption analysis, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The cobalt to aluminum ratios used were 1:9, 1:3, 1:1, 1:1/3, and 1:0. From characterization, the Co-Al pillared bentonite featured a specific surface area of up to 114 m2/g (pristine bentonite = 42 m2/g). In the adsorption test, an enhanced ethylene uptake of up to 6 times (at ambient temperature) compared to pristine bentonite was obtained. Thus, the results highlight the potential of cobalt oxide/pillared clay as ethylene scavenger
Exceptional Aromatic Distribution in the Conversion of Palm-Oil to Biohydrocarbon Using Zeolite-Based Catalyst
Get PDFA series of four catalysts, i.e. ZSM-5 (Si/Al = 25) (Z1), a combination of ZSM-5 (Si/Al = 25) and zeolite Y (Si/Al = 25) (Z2), zeolite Y (Si/Al = 25) (Z3), and ZSM-5 (Si/Al = 80) (Z4), was successfully prepared for catalytic cracking of palm oil. All three catalysts utilized silica as a binder without other additional components. Catalytic cracking tests showed that the aromatic distribution was very high, according to the following order: Z4 (98%) > Z1 (90%) > Z2 (84%) > Z3 (60%). It was shown that ZSM-5 promotes the formation of aromatics better than zeolite Y does. From 98% of aromatics products in Z1, 71% were benzene, toluene, and xylene (BTX). It appears that the formation of aromatics needs milder acidity since a higher number of acids extends the cracking reaction, resulting in the formation of more gaseous and heavy aromatics products. The results of this study show potential for the sustainable production of bio-hydrocarbons with exceptional aromatic distributions, which may fulfill the demands of the petroleum, petrochemical, and fine chemical sectors
Experimental Investigation of LPG/H2/Air Premixed Flame Stability Zone
No full textFlame stability, environmental changes and fossil fuel shortage represent major challenges to any successful combustion device utilization. In this study, the stability zone of laminar premixed ILPG/ -air flames was investigated experimentally. Non-swirling burners with different diameters (10, 12.5, and 17 mm) were employed to characterize the flashback and blow-off limits. Different hydrogen blends (0%-50%) at equivalence ratios (ER) (0.6-1.4) were used. The results show that maximum flashback limits occurred at ER slightly richer than stoichiometric, with the mixture flow rate at a flashback of (3.75, 7.25 and 14) LPM for the 50% hydrogen blending ratio and a burner diameter of (10, 12.5 and 17 mm), respectively. When hydrogen blending was 50% at stoichiometric condition, the critical velocity gradient at flashback increased from (469.9-650.8 1/s) with 10 mm diameter, and the critical velocity gradient at blow-off increased from (1538-2936 1/s). It was observed that the flashback limits decreased with increasing burner diameter. Its limit increased with increasing hydrogen addition to the ILPG. The blow-off limit increased with increasing fuel concentration. This paper further presents the stability zone for ILPG/air combustion for a non-swirling burner with a 10-mm diameter and different hydrogen blends. It was found that the stability zone was narrow on the lean combustion side and enhanced with increasing diameter and hydrogen addition
Experimental Study of Wind Flow in a Street Canyon between High-Rise Buildings Using PIV
Get PDFIn recent years there have been several occasions of failure of non-buildings such as billboard towers and pedestrian bridges around high-rise areas in urban Indonesia. Most cases did not occur during any particular high-speed wind gusts but rather during normal wind speed. This research aimed to show the increase in wind load for structures built between high-rise buildings. A simplified cluster of 4 symmetrical high-rise building was investigated. The study used a wind tunnel and a Particle Image Velocimetry (PIV) device in the experiment. Several angles of attack and also different distances between buildings were investigated to see the impact of these parameters on the wind flow between the buildings. Wind flow experiences an interaction flow in all central areas, which translates into an increase in speed. The change in distance between buildings changes the behavior of the flow in the cross area while a change in the angle of attack of the wind does not influence the amplification factor. The results show that there was an increase from 7 to 44% in wind speed due to the street canyons and that the highest amplification occurred with an angle of attack of 0°
Improvement of Tar Removal Performance in Biomass Gasification Using Fixed-Bed Biomass Filtration
Get PDFSeveral studies have proven the efficiency of gasification as a thermal process in terms of material decomposition and chemical energy. Synthetic gas (syngas) is a gasification product that can be used as an energy source. However, it needs to undergo treatment to remove the tar content, which could cause several issues in the combustion system. Tar removal can be conducted through biomass filters. In this study, three types of filters were investigated: biochar, rice straw, and rice husk filters. Three thicknesses of the porous media (30, 40, and 50 cm) were investigated. The results revealed that porous media thickness significantly affects tar removal efficiency, as the efficiency was found to increase with the thickness. Biochar was proven to be the best filter media among the three types, with a tar removal efficiency of 59.45% at a thickness of 50 cm
Snap-Fit Joinery System Using Pinewood Material Elasticity Properties
Get PDFThe elasticity of pinewood gives it the potential to be applied in a snap-fit system, a connection system that utilizes the elasticity of a material to connect separate parts to one another. This research was aimed at finding the right shape of the stress-relievers for pinewood snap-fit modules. An experiment was performed using a computer-numerical-control (CNC) router for fabrication with detailed precision
Microplastics Contamination in a High Population Density Area of the Chao Phraya River, Bangkok
Get PDFMicroplastics (MPs) are distributed globally, including in aquatic environments. While a large number of studies on MPs in marine environments have been performed, few studies are available in freshwater environments. Therefore, the distribution of MPs in surface water and sediment from the Chao Phraya River at Tha Prachan, a high population density area of Bangkok, was investigated. Water samples were collected by a manta trawl with a net mesh size of 300 mm. Sediment samples were collected by a Van Veen grab sampler. The total number and concentration of MPs in the water samples were found to be 104 particles/m3 and 805.20 mg/m3, respectively. The dominant MPs were fragments, 0.5 to 1.0 mm in size, for the water samples. In the sediment, MPs were detected only in a size range of 0.053 to 0.5 mm with a total number and concentration of 2,290 particles/kg and 650 mg/kg, respectively. The presence of different types of MPs was confirmed by Fourier-transform infrared spectroscopy with a dominant abundance of polypropylene, polyethylene, and polystyrene. In brief, this study suggests that high levels of MPs occur not only in the water but also in the sediment of the Chao Phraya River at Tha Prachan area
Stress Intensity Factors for Crack Problems in Bonded Dissimilar Materials
Get PDFThe inclined crack problem in bonded dissimilar materials was considered in this study. The system of hypersingular integral equations (HSIEs) was formulated using the modified complex potentials (MCP) function method, where the continuity conditions of the resultant force and the displacement are applied. In the equations, the crack opening displacement (COD) serves as the unknown function and the traction along the cracks as the right-hand terms. By applying the curved length coordinate method and the appropriate quadrature formulas, the HSIEs are reduced to the system of linear equations. It was found that the nondimensional stress intensity factors (SIF) at the crack tips depend on the ratio of elastic constants, the crack geometries and the distance between the crack and the boundary
Investigation of Alkaline Surface Treatment Effected on Flax Fibre Woven Fabric with Biodegradable Polymer Based on Mechanical Properties
Get PDFBiodegradable polymers such as polylactic acid (PLA) are used nowadays due to their degradability, durability and environmentally friendly properties. Alkaline surface treatment of natural fibres is used to increase the flexural properties of composites. This research investigated the flexural properties of dry compressed PLA, wet mix PLA, untreated flax/PLA and treated flax/PLA composites. The flax fibre was first treated with NaOH. The wet mix PLA was prepared via solvent casting with chloroform and dried at room temperature overnight followed by post-drying in an oven. The flax/PLA composites were fabricated using a hot press for 6 minutes. The wet mix PLA showed higher flexural strength compared to the dry compressed PLA. The treated flax fibre composite showed higher flexural strength compared to the untreated flax fibre. The flexural strength and elongation at break of the treated flax fibre composite was increased by 4.79% and 27.76%, respectively, while the flexural modulus decreased by 0.79% compared with the untreated flax composite. The treated flax composite also showed an improvement in impact properties, increasing its impact strength by about 3% and 10% at energy levels of 10 J, 15 J, and 17.5 J compared with the untreated flax fibre. Therefore, the investigation of the surface treatment of flax in a PLA matrix based on its mechanical properties revealed better properties compared to untreated flax/PLA composite