Aceh International Journal of Science and Technology
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Promotion and Implementation of Bioenergy for a Better Environment
Get PDFAbstract - There is strong scientific evidence that the average temperature of the earths surface is rising and this may be attribute to increased concentration of carbon dioxide (CO2), and other greenhouse gases (GHGs) in the atmosphere as released by burning fossil fuels. One of the chief sources of greenhouse gases is burning of fossil fuels. Biogas from biomass appears to have potential as an alternative energy source, which is potentially rich in biomass resources. In the present paper, current literature is reviewed regarding the ecological, social, cultural and economic impacts of biogas technology. In this article an attempt has been made to give an overview of present and future use of biomass as an industrial feedstock for production of fuels, chemicals and other materials. However, to be truly competitive in an open market situation, higher value products are required
Preliminary Study on the Kinetics and Mechanism of the Oxidation of Naphthol Green B by Dichromate Ion in Aqueous Hydrochloric Acid Medium
Get PDFAbstract - The kinetics of the oxidation of naphthol green B (NGB3-) by Cr2O7 2- has been studied in aqueous hydrochloric acid medium at an ionic strength, I = 0.50 mol dm-3 (NaCl), H+ =1.0 10-4 mol dm-3 (HCl) and T = 25 1C. The redox reaction displayed a stoichiometry of 1:1 and obeys the rate law: -dNGB3-/dt = k2NGB3-]Cr2O7 2- . The second order rate constant increases with increase in acid concentration and in the ionic strength of reaction medium. The rates of reaction displayed a positive salt effect. Addition of acrylonitrile to a partially reacted mixture in the presence of excess methanol did not lead to gel formation. Added cations and anions inhibited the naphthol green B - Cr2O7 2- reaction. Results of the Michaelis Menten plot gave no evidence of intermediate complex formation during the course of the reaction. Based on the results obtained, the reaction is believed to proceed through the outersphere mechanistic pathway.Keywords: Intermediate; Redox; Pseudo-octahedral; Michaelis Menton; Outerspher
Role of Age Hardening Heat Treatment on the Hardness Values of 93.95 Al-5 Zn-1.05 Sn/5 Al2o3- Sio2 Particulate Composite
Get PDFAbstract - The effect of age hardening heat treatment on the hardness values of 93.95Al-5Zn-1.05Sn/5Al2O3-SiO2 particulate composite has been studied. The data used for the work was generated at the National Metallurgical Development Centre, Jos Foundry shop, where the composite was developed. The composite was developed using the stir cast method. The result of the work has shown that the composite has a response to age hardening heat treatment with the optimum hardness value occurring at 2 hours of age hardening. A model was developed for the relationship between age hardening time and hardness of the composite. It was tested, and the product moment of correlation and the coefficient of correlation values attested to the degree of correlation existing between the two variables
Antibacterial Activities and Mechanism of Action of Acetone Extracts from Rabdosia rubescens
Get PDFThe antibacterial activities and mechanism of action of acetone extracts from R. rubescens were reported in this paper. The results showed that 80% acetone extracts had both the highest contents of total phenolics and flavonoids. Acetone extracts showed better antibacterial activities against Gram-positive bacterial strains and there were no inhibitory effects found on tested Gram-negative bacteria. In addition, 80% acetone extracts from R. rubescens had relatively higher antibacterial activities with the lowest values of MIC and MBC at 2.5 mg/mL and 5 mg/mL against B. subtilis. The antibacterial mechanism of 80% acetone extracts against Bacillus subtilis might be described as disrupting cell wall, increasing cell membrane permeability, and finally leading to the leakage of cell constituent
Preparation of Metal Immobilized Orange Waste Gel for Arsenic(V) Removal From Water
Get PDFAbstract - The toxicity of arsenic is known to be a risk to aquatic flora and fauna and to human health even in relatively low concentration. In this research an adsorption gel was prepared from agricultural waste material (orange waste) through simple chemical modification in the view to remove arsenic (V) from water. Orange waste was crushed into small particles and saponified with Ca(OH)2 to prepare saponified orange waste, which was further modified by immobilizing gadolinium(III) to obtain desired adsorption material (Gd(III)-immobilized SOW gel). The effective pH range for arsenic adsorption was found to be 7.5 8.5. Adsorption capacity of the gel was evaluated to be 0.45 mol-arsenic (V)/kg. Dynamic adsorption of arsenic (V) in column-mode was conducted and a dynamic capacity was found to be 0.39 mol/kg. Elution of arsenate was tested after complete saturation of the column packed with gadolinium-immobilized orange waste adsorption gel. A complete elution of arsenate was achieved with the help of 1 M HCl and 28 times pre-concentration factor was attained. This study showed that a cheap and abundant agro-industrial waste material could be successfully employed for the remediation of arsenic pollution in aquatic environment.Keywords: Arsenic; Orange waste; Gadolinium(III); Adsorption; Elution
Corrosion Inhibition Study of Mild Steel in Acidic Medium by Antibiotic Drugs: A Comparative Study
Get PDFAbstract - A comparison of the inhibiting efficiency of antibiotic drugs (ciprofloxacin, cloxacillin, and amoxicillin) on the corrosion of mild steel in 1 molL1 HCl were studied at room temperature using mass loss measurement. The main reason is probably be due to the formation of protective coverage by the inhibitor as other authors reported previously. Adsorption characteristics of the inhibitor has also been studied using simple equation and it was found that drugs inhibits the corrosion of mild steel by being adsorbed on the surface of mild steel by a physical adsorption mechanism. The adsorption of drugs on the mild steel surface was found to be spontaneous and obey the Langmuir adsorption isotherm model. It was observed that the test drug has a promising inhibitory action in acid medium against corrosion of mild steel. Moreover it was revealed that an inhibition efficiency of 80.1 % can be achieved with 310-3M ciprofloxacin drug treatment on mild steel.Keywords: Steel corrosion; Antibiotic drugs; Adsorption isotherm; Inhibition mechanism
Contribution of Heat Fluxes on Cyclone Narelle as Simulated by a Mesoscale Model
Get PDFAbstract - Heat fluxes from oceanic evaporation particularly latent heat is important to drive the formation and intensification of Cyclone Narelle. The research was carried out by introducing a mesoscale model, namely Weather and Research Forecasting (WRF). One domain with spatial resolution at 10 km was utilized in the model. The model involved significant physical parameters, e.g., Kain-Fritsch in the cumulus scheme, Yonsei University in the Planetary Boundary Layer scheme, and WRF Single-Moment 3-class in the microphysics scheme. The analysis focused on January 8th to 14th upon all stages of Narelle. The result showed that Sea Surface Temperatures (SST) higher than 26C was a favorable environment for Cylone Narelle to form. Surface sensible and latent heat fluxes have strong positive correlation with wind speed and SST. It can be concluded that these variables were highly correlated with surface heat flux that further lead to the formation and intensification of Cyclone Narelle in early January 2013 over South Indian Ocean. The tracks and stages of the model are nearly similar to the observations, the differences are found in late phases of Narelle.Keywords: Latent heat; WRF; SST; Sensible heat; Wind spee
Hydrological Data Banking for Sustainable Development in Nigeria: An Overview
Get PDFAbstract - This paper examines the importance of hydrological data banking for sustainable development in Nigeria. Water related projects have failed woefully in Nigeria because they are executed without recourse to or lack of relevant hydrological data. Hydrologists primarily are saddled with the responsibilities of data gathering, processing, storage and retrieval on all components of the hydrological cycle such as precipitation, evaporation, runoff, infiltration, stream flow to mention a few. This however can only be done when hydrologists are adequately trained and efficient hydrological gauging stations with up to date equipment are established. The current situation in Nigeria is that hydrological data banking is lacking which is linked with inadequate and inefficient guaging stations and trained manpower. There is the need to make hydrological data collection, processing, storage/retrieval and banking for sustainable development a must in Nigeria. Government and relevant agencies and institutions need to step up action in this wise.Keywords: Hydrology, water inventory, river, data bankin
Effects of Dietary Katuk Leaf Extract on Growth Performance, Feeding Behavior and Water Quality of Grouper Epinephelus coioides
Get PDFAbstract - Plant-derived materials are believed as potential nutrient sources to be applied in aquaculture. Although many studies to assess the benefits of plant extracts have been conducted, however effects of dietary katuk (Sauropus androgynus L. Merr.) on growth performances, feeding behavior and water quality of grouper (Epinephelus coioides) are not well known. In this study, 25 grouper juveniles weighing 11.27 2.53 g were reared into 100-L tank (60 x 50 x 35 cm) and cultivated for 70 days. The fish were divided into four groups in triplicate, and were offered diet without katuk extract (control), diet supplemented with 1% katuk extract (SAA); diet supplemented with 2.5% katuk extract (SAB) and diet supplemented with 5.0% katuk extract (SAC) twice daily. Statistical analyses showed that dietary katuk extract caused a significant (P 0.05) increase in growth rate and feed intake. The efficiency of feed was also significant when fish offered diets supplemented with 1% of katuk extract which indicated by a lower feed conversion ratio. However, no statistical differences were observed on the survival rate, condition factor, viscerosomatic index and hepatosomatic index. Observation on feeding behavior found that all treated fish consumed compounded diet just after provided into their tank and there were no abnormal behavior or any healthy problems during experimental periods. It demonstrated that application of katuk extract in fish diets is acceptable and can stimulate the fish appetites. In conclusion, our studies indicated that dietary katuk (Sauropus androgynus) extract can be applied in aquaculture to stimulate the growth and improve feed utilization.Keywords: Feed conversion ratio, feed utilization, plant extract, Sauropus androgynus
Determination of the Cascade Reservoir Operation for Optimal Firm-Energy Using Genetic Algorithms
Get PDFAbstract - Indonesia today face a new paradigm in water management where aim to apply integrated water resources management has become unavoidable task in purpose of achieving greater level of effectiveness and efficiency. On of most interesting case study is the case of Citarum river, one of the most potential river for water supply in West Java, Indonesia. Alongside the river, Saguling, Cirata and Djuanda Reservoirs had been constructed in series/cascade. Saguling and Cirata reservoirs are particularly operated for hydroelectric power and Djuanda is multipurpose reservoir mainly operated for irrigation and contribute domestic water supply for Jakarta (capital city of Indonesia). Basically all reservoirs are relying on same resources, therefore this condition has considered addressing management and operational problem. Therefore, an approach toward new management and operation system are urgently required in order to achieve the effective and efficient output and to avoid conflicts of water used. This study aims to obtain energy production from Citarum Cascade Reservoir System using Genetic Algorithms optimization with the objective function to maximize firm-energy. Firm-energy is the minimum energy requirements must be available in a certain time period. Then, the result obtained by using the energy produced by GA is compared to the conventional searching technique of Non-Linier Programming (NLP). The GA derived operating curves reveal the higher energy and firm-energy than NLP model.Keywords: Genetic Algorithms, Citarum Cascade Reservoir, Firm-Energy, Electrical Energ