Journal of Engineering and Technological Sciences
Not a member yet
888 research outputs found
Sort by
Promising Adsorption of Sulfidic Acid Gases Using Wet Banana Plant Adsorbent (Musa spp.)
Get PDFBananas have the highest production rate among fruits in Indonesia, which leads to the generation of a significant amount of banana fruit solid waste. In this study, we assessed the potential use of banana waste to remove hydrogen sulfide (H2S) gas. In particular, the purpose of this study was to analyze the efficiency of banana waste as an adsorbent for H2S gas. We tested the stems, leaves, and peels of banana plants as H2S gas adsorbents with varying contact times. To obtain a microscopic view of the adsorbents before and after the experiment, we conducted measurements using scanning electron microscopy with dispersive X-ray spectroscopy. The banana leaves, stems, and peels were found to have H2S gas absorption efficiency values of 76.52%, 51.83%, and 6.44%, respectively. Based on the experiment, the leaves of the banana plant appear to be the best adsorbents, with an adsorption capacity of 1.67 mg/g. The results also revealed that there was a change in the fiber and stomata appearance of the banana leaves after the adsorption process. Overall, this research indicates that banana leaves have the potential to be used as effective H2S adsorbents
Wastewater Processing Technology Opportunities for Palm Oil Mill Effluent as a Raw Material for Renewable Bioenergy
Get PDFThe effect of pH on the formation of hydrogen and ethanol using POME as the substrate has not been widely studied. Indonesia, which is the largest producer of palm oil, has a high potential for the utilization of this liquid waste as a substrate for the formation of hydrogen and ethanol. This study determined the optimum hydrogen and ethanol production conditions by controlling pH. POME was used as substrate in an anaerobic reactor and operated in feed batch mode for 72 hours. Mixed culture anaerobic bacteria as biomass were used in the reactor. The pH of the reactor was adjusted to 4.5, 5.5, 6.5, and 7.5 using NaOH 0.1 N and HCl 0.1 N. The reactor’s performance was investigated by measuring hydrogen production, ethanol production, and volatile fatty acid product. It was found that with an initial pH of 5.5, hydrogen production was higher than for the other pH conditions, at about 14.7% v/v. In contrast, the most increased ethanol production occurred in the reactor with an initial pH of 6.5 with a concentration of 347.7 mg/L. Based on the results of this study, the right pH setting can optimize hydrogen and ethanol production
Operating Variables on Production of High Purity Bio-silica from Rice Hull Ash by Extraction Process
Get PDFThe huge amount of rice hull biomass available in Indonesia can be utilized as raw material for bio-silica production. This study investigated the production of high-purity bio-silica from rice hull ash through an alkaline extraction process. A full factorial design (FFD) was used to screen for significant effects of the observed variables. Three operating variables – acid concentration, solvent to feed ratio (RS/F), and extraction time – were investigated with the purpose of obtaining a high yield and high purity of bio-silica. Yield and purity above 96% were achieved by using pretreatment with 1 mol/L HCl. Employing an RS/F of 5 and a longer extraction time improved the bio-silica yield. The operating variable that enhanced the bio-silica yield and purity most was acid concentration. All variable interactions had an insignificant effect on purity, while two interacting variables had a significant effect on bio-silica yield. Based on the results of this study, rice crop residue can be optimally converted to a bio-silica product in terms of yield and purity by optimizing the most effective operating variables
Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products
Get PDFVolatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data
Experimental and Theoretical Analysis of Throughput of MIMO PLC Network
Get PDFIn this study, we mainly focused on a theoretical analysis of HomePlug 1.0 and an experimental analysis of modem data rates through a section of a PLC network with several configurations. We introduce the utilization of the MIMO technique to increase the throughput over a PLC channel. Besides, we propose a MIMO PLC channel model to evaluate the channel transfer function of MIMO PLC. We used an equivalent per-unit-length model of the indoor power line network to characterize the three-conductor cable. Based on this mathematical model, we analyzed the throughput of the PLC network with different household appliances. The equivalent circuit of each appliance is also given. The simulation results showed that the throughput is influenced by household appliances connected to the sockets of a MIMO PLC network. Moreover, we also compared the throughput between single and multi-antenna systems. Based on the simulation results, we found that the data rate increased with frequency. In addition, the performance of the MIMO PLC system was almost 90% higher than that of a SISO PLC system in terms of channel capacity
Adaptive Fuzzy Proportional Integral Sliding Mode Control for Two-Tank Interacting System
Get PDFThis paper presents an adaptive fuzzy proportional integral sliding mode control (AFPISMC) for two-tank interacting system (TTIS). In order to maintain the desired liquid level of the TTIS and meet the reference values for attenuated chattering problems, this paper proposes a combination of a sliding mode control (SMC) with a proportional integral (PI) sliding surface and a fuzzy inference system. Fuzzy logic and the universal approximation theorem of fuzzy systems are used to approximate the uncertain function in the PISMC. The stability of the control system is proved by the Lyapunov theory. The simulation results of the proposed method in MATLAB/Simulink were compared to a fuzzy control, a sliding mode control with conditional integrals, a fuzzy-PID control, and a conventional PID control. The comparison results showed that the proposed controller was most effective when the rising time reached 0.2375 s, the percent of overshoot was 0%, the steady state error converged to zero, the settling time was 0.4612 s, and chattering was reduced
Geothermal System in Parang Wedang, Yogyakarta, Indonesia
Get PDFGeothermal manifestations in Parangtritis, Indonesia, known as Parang Wedang Hot Spring, indicate a geothermal system in the subsurface. This circumstance motivated our research to model the Parang Wedang geothermal system in order to determine its subsurface conditions. Geological mapping, the geophysical method, and geochemical analysis were integrated to produce a conceptual model of the Parang Wedang geothermal system. The study area consists of structural hills, karst hills, and eolian plains with andesite breccias, limestone, andesite, and sand deposits as lithological variations. The results of magnetic modeling indicate that the research area is associated with the presence of an andesite intrusion and shows a NE-SW trending geological structure that is thought to be a path for hydrothermal fluid to the surface. Geochemical analysis was performed at two hot springs with temperatures of 47 °C and 49 °C. Geothermometer calculation showed that the geothermal reservoir in Parang Wedang has a temperature of 100 to 120 °C, a depth of about 180 to 285 m, and can be classified as a low enthalpy geothermal system
A Study on Small Vehicle Structure in Rear Under-Ride Impact by Using A CAE Based Methodology
Get PDFThis study simulated and evaluated the safety of a small car structure in a collision with the rear of a truck. The parameters of bumpers currently used in Vietnam were employed to build a model of the rear truck bumper. The setting of simulation conditions was based on the NCAP (New Car Assessment Program) crash test. According to actual crash conditions, a collision simulation was performed with different vehicle speeds from 40 to 60 km/h, corresponding to the case of a passenger vehicle moving in a city colliding with a truck standing still. In addition, the percentage of rear-end collision was also taken into account, just like in real-world collisions, at 25%, 50%, and full rear impact. The simulation results were analyzed and evaluated according to the IIHS rating (Institute Insurance for Highway Safety). The results from different case studies showed that the rear bumper typically used on trucks is only safe for passenger cars in a collision at a low speed of 40 km/h and that in a collision at a higher speed will affect the passenger’s safe space and cause high injuries and casualties. Therefore, it is necessary to improve safety by optimizing the rear bumper design and the frontal structure of the small car chassis
Development of Gold Nanoparticle (AuNP)-based Colorimetric Aptasensor for Penicillin G Detection
Get PDFAntibiotics are chemical or biological substances that have the ability to kill pathogens selectively. Currently, high-performance liquid chromatography (HPLC) is used routinely in the detection of antibiotics. However, the cost of analysis and running time are bottlenecks for HPLC to be used for routine tests to detect antibiotics. Alternative methods need to be developed to overcome this issue. In this study, the development of a penicillin G specific biosensor by using a DNA aptamer and gold nanoparticles (AuNPs) was done. Optimal aptasensor conditions were achieved with the concentrations of NaCl and aptamer at 0.25 M and 2 μM, respectively. An aptasensor of this type showed LOD for penicillin G at 3 mg/L and was able to detect penicillin G in the range of 3 to 27 mg/L. The established aptasensor showed specific sensitivity toward penicillin G after testing with several antibiotics, i.e., ampicillin, kanamycin, chloramphenicol, and erythromycin. The aptasensor could detect the presence of penicillin G from culture medium of wild-type, ultraviolet irradiation mutant, gamma irradiation mutant, and ultraviolet irradiation and gamma irradiation mutant strains of P. chrysogenum, at detection concentrations of 9.75 ± 0.004; 25.25 ± 0.005; 37.5 ± 0.005; and 45 ± 0.004 mg/L, respectively
Selective H2S Absorption Using the Mixture of NaOH-NaHCO3-Na2CO3 Buffer Solvent Solution
Get PDFAcid gas enrichment unit (AGEU) involves selective separation of H2S from acid gas mixture, for example using absorption with an NaOH solvent solution. Sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) buffer addition to NaOH solution suppresses CO2 absorption, thereby increasing the selectivity of H2S absorption. This study evaluated the effect of buffer addition to increase H2S absorption selectivity using an NaOH solution. It was shown that both buffer addition and L/G ratio decrease could increase H2S selectivity by limiting CO2 absorption. Based on the simulation results, in the 0.006 to 0.030 L/G ratio range and NaOH solvent concentration greater than 2%-mass, the addition of NaHCO3 with mass ratio greater than 1.5:1 to NaOH and the addition of Na2CO3 at 1.26 times NaHCO3’s mass increased H2S absorption selectivity up to 17.3%. The combination of an L/G ratio of 0.006 and solvent with a composition of 5%-mass NaOH, 15%-mass NaHCO3, and 18.9%-mass Na2CO3 produced the highest H2S selectivity of 23.1 (379.7% H2S selectivity increase)