Journal of Engineering and Technological Sciences
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Solvent Extraction Optimization of Chlorophyll Dye from Conocarpus Lancifolius Leaves
Get PDFRecently, the green food industry has started using chlorophyll dye as a healthy and safe color additive for food and beverages. In this study, a conventional extraction technique was used to extract chlorophyll dye from Conocarpus lancifolius leaves, using 80% acetone as solvent. Taguchi's L25 orthogonal array was utilized to optimize the extraction parameters with total chlorophyll dye yield as the response. The optimum extraction conditions were 75 minutes of extraction time, 33.5 °C extraction temperature and a 118 ml/g solvent to raw leaves ratio. Analysis of variance using Minitab18 was conducted to identify the most significant extraction parameters and available interactions. It was found that the chlorophyll dye yield from Conocarpus lancifolius leaves is mostly dependent on extraction time, followed by mixing ratio and temperature. The analysis showed a large interaction between the extraction parameters studied. The experimental chlorophyll dye yield was in close agreement with the predicted model. The adequacy of the predicted model was confirmed by an experiment conducted under the optimal conditions, given a 3.9% error percentage
Preparation and Characterization of Biopolymer Electrolyte Membranes Based on LiClO4-Complexed Methyl Cellulose as Lithium-ion Battery Separator
Get PDFThe polymer electrolyte membrane is a main component of lithium-ion batteries (LiBs), serving as separator and electrolyte. In this work, we prepared biopolymer electrolyte (BPE) membranes of lithium perchlorate (LiClO4)-complexed methyl cellulose (MC). Methyl cellulose (MC), a cellulose derivative, has attractive properties for use as biopolymer electrolyte. The bulkier anion size of lithium salt (LiClO4) significantly enhances the performance of biopolymer electrolyte (BPE) membranes. The fabricated biopolymer electrolyte (BPE) membranes were characterized by FTIR, EIS, tensile tester, XRD and TGA. Biopolymer electrolyte membranes with various weight percentages of LiClO4 salt (0%, 5%, 10%, 15%, and 20%) were prepared using a simple solution casting technique. Incorporation of 10% weight of LiClO4 into the MC-based host polymer was selected as optimum condition, because this yielded good conductivity (3.66 x 10-5 S cm-1), good mechanical properties (tensile strength 35.97 MPa and elongation at break 14.47%), good thermal stability (208.4 to 338.2 °C) as well as ease of preparation and low cost of production. Based on its characteristics it can be stated that the 10% LiClO4-complexed MC membrane meets the requirements as a candidate separator for lithium-ion battery application
Reconnaissance on Liquefaction-induced Flow Failure Caused by the 2018 Mw 7.5 Sulawesi Earthquake, Palu, Indonesia
Get PDFThe Mw 7.5 Sulawesi Earthquake 2018 was a catastrophic disaster that resulted in large numbers of casualties. This study aimed to investigate the damages of liquefaction-induced-flow failure in three areas in Palu city, i.e. Petobo, Balaroa, and Jono Oge. It was found that this flow failure occurred on a large scale at a very gentle ground inclination, ranging from 1 to 3%. In order to gain an understanding of the soil conditions in these specific locations, Portable Dynamic Cone Penetration Tests were conducted in Petobo. The results showed that the soil layers in the affected area were in a loose state compared to the non-affected areas. Furthermore, some spots of freshwater inundation were recognized in Petobo and Balaroa, even two weeks after the disaster. Based on this evidence, a mechanism of liquefaction-induced-flow failure caused by a confined aquifer is proposed
Torrefaction of Rubberwood Waste: The Effects of Particle Size, Temperature & Residence Time
Get PDFAgriculture waste has created massive challenges over the last few decades and yet also opportunities. This work aimed to produce high-quality biochar from rubberwood waste with calorific properties close to subbituminous coal. Using a tubular vertical reactor, the effects of rubberwood particle size (wood chips and shredded wood), torrefaction temperature (220, 260, and 300 °C), and residence time (30, 60, and 90 minutes) on the quality of torrefied rubberwood were studied. The results showed that the mass loss of the rubberwood increased as the temperature increased. Also, the particle size and residence time increased due to excessive devolatilization. A higher fixed-carbon content and calorific value as well as lower moisture and volatile-matter content were achieved by increasing the torrefaction temperature and residence time in comparison to the untreated sample (raw rubberwood). The highest fixed-carbon content and calorific value were found to be 56.7% and 6313 kcal/kg, respectively, for the wood chip particles that were torrefied at 300 °C for 60 minutes. Based on the Van Krevelen diagram, torrefaction of woodchip rubberwood at 300 °C with a residence time of 60 minutes demonstrated the optimum condition to generate a product with properties that are close to those of subbituminous rank coal
Challenges and Opportunities for Septage Management in the Urban Areas of Indonesia â Case Study in Bandung City
Get PDFBecause of the burgeoning urban population, there is huge pressure on both natural resources and basic urban infrastructure, especially sewerage systems, with Indonesia as no exception. It is estimated that about 95% of human waste in Indonesia ends up untreated or partially treated in septic tanks before being discharged in the natural environment, contaminating the living environment as well as adversely affecting human health and economic development. This study conducted a comprehensive investigation on septage management in Bandung City, Indonesia, to gain a better understanding of the challenges and opportunities for improved performance of on-site sanitation systems as well as septage management across its sanitation service chain. The results showed that the following issues are the main reasons behind poor sanitation in Bandung city: a) poor design and construction of septic tanks with no or only partial lining, resulting in leaking (>90% of septic tanks are malfunctioning); b) irregular desludging, i.e. about 2/3 of population desludge their septic tanks only once in more than 5 years; c) lack of proper guidelines and awareness about the benefits of regular monitoring and operation of septic tanks; d) lack of good sanitation service providers; and e) lack of funds for building sufficient capacity of septage treatment plants
Identification of Micro-plastics (MPs) in Conventional Tap Water Sourced from Thailand
Get PDFIn a period when MP contamination of drinking water is a great concern, this study focused on the size- and morphology-based count, and polymeric identification of plastic particles in tap water sourced from Thailand. A total of 45 human consumable samples (each 1 L) were collected at Thammasat University. The average MP counts sorted by Nile Red tagging were 56.0±14.0 p/L (6.5-53 µm) and 21.0±7.0 p/L (53-300 µm), while those found by optical microscopic observations were 13.0±5.0 p/L (300-500 µm) and 6.0±3.0 p/L (≥ 500 µm). A significantly high MP amount was observed in the 6.5-53 µm fraction. Fibers dominated in all samples, accounting for 58% of the particle count. Most ≥ 300 µm particles tested by ATR-FT-IR spectroscopy were confirmed to be polymeric, identified as PE, PVC, PET, PA, PTFE, PP, and PAM. These particles may have escaped from the treatment plant or were added along the water distribution network. Since MPs in drinking water constitute a potential health risk by exposing humans to direct plastics intake, MP contamination in water supply systems should be controlled
An Investigation of Building Seismic Design Parameters in Mataram City Using Lombok Earthquake 2018 Ground Motion
Get PDFMataram is the capital of West Nusa Tenggara. West Nusa Tenggara is made up of two islands, Lombok and Sumbawa. The 2018 earthquake on Lombok undoubtedly affected spectral acceleration. This is an important factor to be addressed in structural design. Short-period spectral acceleration, SS,increases 18.323% compared to the value listed in seismic code SNI 1976:2012, corresponding to a 2500-year return period. However, even if the SS value increases, the design category of the building does not change and remains in the D category. In general, the acceleration value in this study was found to be relatively greater than that of the existing code for periods of less than 0.462 s for site class D and in periods of less than 0.830 s in site class E. In addition, the seismic response coefficient, CS, for medium soil increases by 10.782% compared to the CS calculated using of the current code. This effect is more severe in soft soil areas, where the increase reaches 13.168%. Improving existing codes with seismic design parameters for new buildings affected by the ground motion of recent strong earthquakes will lead to more preparedness and will be an important part of local disaster risk reduction
Review on Unconventional Wind Energy
Get PDFFossil fuel is the major source of energy and is a fast depleting resource. The phenomenal increase in fossil fuel consumption has adversely affected carbon footprint impacting our environment. With strict environmental regulations in place, the focus towards renewable sources of energy is gaining momentum supported by recent advancement in technologies in wind, hydro and solar. Wind turbines were the first forms of clean energy has seen a major increase in power production. The site restrictions, have limited the wind turbine from being used to its maximum potential. In recent years, the concept of some unconventional methods is being proposed. In this review, the various types of wind turbines are emphasized with their recent advances and depicting the challenges faced in various aspects. The reviews contain details mainly about 4 types of wind turbines i.e. floating offshore wind turbine, airborne wind turbine, highway wind turbine systems and locomotive mounted wind turbine
Study on the Influence of Toilet Siphon Pipe Shape on Flushing Performance
Get PDFThe goal of this work was to explore the influence of toilet siphon pipe shape on flushing performance. The flushing processes of a toilet under different shape parameters were simulated by using computational fluid dynamics (CFD) with a volume of fluid (VOF) multiphase model. The effects of siphon pipe shape on flushing performance were analyzed in detail. The interpretation of the simulation results was experimentally validated. The results reveal that a toilet may obtain good flushing performance under one single shape parameter when the climbing angle, the arc width, the arc height, the pipe diameter, the climbing width, and the climbing height are about 48°, 45 mm, 210 mm, 50 mm, 90 mm and 30 mm, respectively. With the increase of the siphon pipe diameter, the toilet flushing performance peaks in the range between 50 and 53 mm rather than continuing to improve. In order to reasonably evaluate the flushing effect of the toilet, all flow parameters on a characteristic cross section of the siphon pipe, including the average velocity, the average pressure and the average mass flow rate, should be comprehensively considered instead of one single parameter. The findings of this study provide a reference for the pipe shape design of toilets
Behavior of RCS Connections with Void Web Under Cyclic Load Reversals
Get PDFIn this study, the inelastic cyclic behavior of hybrid connections consisting of reinforced concrete column and steel beams (RCS) was investigated. The experimental results from the lateral load testing of four interior RCS subassembly connections are presented. The first specimen was designed based on the ASCE Guidelines 1994, with connection details based on the study of Liang and Parra-Montesinos (2004), while another specimen was a proposed joint detail. The joint detail was developed to overcome the main problems with RCS frame systems, which is constructability. The behavior of the beam-column joints was evaluated in terms of strength capacity, stiffness degradation, energy dissipation, and joint shear distortion. Comparing all specimens based on the load-displacement hysteresis curves indicated that the specimen with the combination of ABP and EBP had relatively better performance in terms of strength, stiffness, and energy dissipation. ABP and EBF in the joint with a void web were able to withstand joint shear deformation exceeding 0.01 rad, with only low to medium level of damage. EBF was proven to be very effective in providing confinement and reducing the damage level in the joint panel. The existence of a void web did not affect the reduction of joint shear strength.