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Research in the field of Telecommunication is dynamic and continuously working towards the social community of the people. Among that predicting the customer’s who likes to switch from the current network provider is the most important part of telecom industry. However, there are a lot of research has done on this topic, but still more improvements and advancements are expected. In this position paper, we put forward the comparison model of different churn mining methods that intends to help in predicting the customer churn rate in a better way. This paper provides a benchmark of various mining algorithms and its methods for prediction of customer churn rate, which makes the telecommunication industry to setup the retention policies with the increase of their profit.

The presence of heavy metal in wastewater is a major concern due to their toxicity towards living organism and also human. There are different methods in removing heavy metals and one of it is biosorption. The aim of this study is to investigate the ability of mangosteen rind as biosorbent in removal of zinc in wastewater, a typical Malaysian agricultural waste. The mangosteen rind are washed, dried, cut and grounded into powder form. Then it is rinsed with 0.1 mol nitric acid, filtered using filter paper, and neutralized by washing with distilled water. Batch adsorption study was carried out to determine the optimum pH condition for zinc removal. Therefore, experiment was conducted with different pH condition for wastewater by addition of acid or base. By referring to Beer’s Law calibration graph from spectrophotometer, the final concentration of zinc in the wastewater was determined. In order to ensure the consistency of data, three trials were carried out and the results are found to be consistent. The optimum pH for zinc removal is 5.5, with an average removal of 91.5 %, equivalent to 4.55 mg/g removal out of 5.00 mg/g of zinc solution. The condition is compared with past research that uses lemon and banana peels as biosorbent, and mangosteen rind is found to be the best agriculture waste among the three.

Due the environmental problem and limited resources of petroleum has increase, the concern to produce biodiesel has increase too. This paper studies the physical properties of trans esterification from Palm Oil Mill Effluent (POME) to be biodiesel. POME is a liquid waste from palm oil production. Trans esterification of POME has been done by using methanol and catalyst from natural zeolite which are heat at 60 °C in 4 hours. The physical properties analyses of POME trans esterification are density, kinematic viscosity, flash point and pour point. The result is compared with Biodiesel Standard (KDJMGB No. 13483 K/DJM/2006).Due the environmental problem and limited resources of petroleum has increase, the concern to produce biodiesel has increase too. This paper studies the physical properties of trans esterification from Palm Oil Mill Effluent (POME) to be biodiesel. POME is a liquid waste from palm oil production. Trans esterification of POME has been done by using methanol and catalyst from natural zeolite which are heat at 60 °C in 4 hours. The physical properties analyses of POME trans esterification are density, kinematic viscosity, flash point and pour point. The result is compared with Biodiesel Standard (KDJMGB No. 13483 K/DJM/2006).

The beverage industry wastewater contains high COD, TSS, and color. The development of efficient process treatment is needed to reduce the pollutant concentration from beverage industry wastewater. In this paper, the application of electrocoagulation and adsorption using activated carbon were investigated. The optimum conditions for electrocoagulation process were inter-electrode distance 2 cm, 12 voltage and monopolar arrangement which reduced color, COD, and TSS for 51.3, 56.3, and 70.2%, respectively. The further step was adsorption process with 10 g/L dose of powder activated carbon. It reduced color, COD, and TSS for 98.66, 92.15, and 90.12%, respectively. The results showed that electrocoagulation and adsorption could treat beverage industry wastewater into fulfilled the established quality standards.The beverage industry wastewater contains high COD, TSS, and color. The development of efficient process treatment is needed to reduce the pollutant concentration from beverage industry wastewater. In this paper, the application of electrocoagulation and adsorption using activated carbon were investigated. The optimum conditions for electrocoagulation process were inter-electrode distance 2 cm, 12 voltage and monopolar arrangement which reduced color, COD, and TSS for 51.3, 56.3, and 70.2%, respectively. The further step was adsorption process with 10 g/L dose of powder activated carbon. It reduced color, COD, and TSS for 98.66, 92.15, and 90.12%, respectively. The results showed that electrocoagulation and adsorption could treat beverage industry wastewater into fulfilled the established quality standards.

Biomass from palm oil plant waste in the form of palm fronds that are abundant but underutilized. Considering the large and consistent supply, oil palm fronds (OPF) could be a promising source of biomass energy through gasification. This Paper presents an experimental evaluation the quality of the producer gas in a two-stage gasifier, for different operating conditions. Varying the equivalent ratio (ER) to the gasifier and the distribution of gasification air between each gasification stages (ARpir-oks). The gas composition and its lower heating value (LHV) were also determined. Experimental tests were performed varying the operating conditions of the gasifier: the air flow between 17,3 kg/h, 23,1 kg/h, and 28,9 kg/h (the proximate equivalence ratio from 0,3, 0,4 and 0.5) and the air flow ratio in the two stages (ARpir-oks) between 0%, 70%, 80%, and 90%, evaluating the effects of these parameters over the quality of the gas. The results show that a highest CO content (22.1% v) was achieved for airflow 23.1 kg / s (ER 0.4) at AR 90% along with decreasing CH4 (0.97% v) while H2 (16, 27% v) highest achieved at AR 80%. LHV gas shows maximum value at 4542.5 Kj/kg achieved at Air Ratio (AR) 90% with air flow 23.1 kg / s (ER 0.4). Gasification of two-stageair supply increase gas composition and allowed to reduce the tar content in the producer gas. This result can be explained by increasing temperature in pyrolysis and combustion zone. Good stability and performance of pyrolysis and combustion zones, H2O and CO2 formed in this zone and their interaction with charcoal is excellent in endothermicwater-gas reaction and boudouard reaction.Biomass from palm oil plant waste in the form of palm fronds that are abundant but underutilized. Considering the large and consistent supply, oil palm fronds (OPF) could be a promising source of biomass energy through gasification. This Paper presents an experimental evaluation the quality of the producer gas in a two-stage gasifier, for different operating conditions. Varying the equivalent ratio (ER) to the gasifier and the distribution of gasification air between each gasification stages (ARpir-oks). The gas composition and its lower heating value (LHV) were also determined. Experimental tests were performed varying the operating conditions of the gasifier: the air flow between 17,3 kg/h, 23,1 kg/h, and 28,9 kg/h (the proximate equivalence ratio from 0,3, 0,4 and 0.5) and the air flow ratio in the two stages (ARpir-oks) between 0%, 70%, 80%, and 90%, evaluating the effects of these parameters over the quality of the gas. The results show that a highest CO content (22.1% v) was achieved for airflow 23....

Bio-energy is renewable energy made from plant. Biomass-based energy sources are potentially CO2 neutral and recycle the same carbon atoms. In order to reduce pollution caused by fossil fuel combustion either for mechanical or electrical energy generation, the performance characteristic of purified palm oil blends are analyzed at various ratios. Bio-energy, Pure Plant Oil, represent a sustainable solution.A generator has been modified due to adapt the viscosity ofblended fuel, PPO - diesel, by pre-heating. Several PPO - diesel composition and injection timing were tested in order to investigate the characteristic of mixed fuel with and without pre-heating. The term biofuel refers to liquid or gaseous fuels for the internal combustion engines that are predominantly produced fro m biomass. Surprising result showed that BSFC of blended PPO - diesel was more efficient when injection timing set more than 15° BTDC. The mixed fuel produced power with less mixed fuel even though the calorie content of diesel is higher than PPO. The most efficient was 20% PPO in diesel with BSFC 296 gr fuel / kwh rather than 100% diesel with BSFC 309 gr fuel / kwh at the same injection timing 18° BTDC with pre-heating. The improvement of BSFC is caused by heating up of mixed fuel which it added calorie in the mixed fuel. Therefore, the heating up of blended PPO - diesel is not only to adapt the viscosity but also improving the efficiency of fuel usage representing by lower BSFC. In addition, torque of the 20% PPO was also as smooth as 100% diesel representing by almost the same torqueat injection timing 15° BTDC. The AIP Proceedings article template has many predefined paragraph styles for you to use/apply as you write your paper. To format your abstract, use the Microsoft Word template style: Abstract. Each paper must include an abstract. Begin the abstract with the word “Abstract” followed by a period in bold font, and then continue with a normal 9 point font.

Polybenzimidazole (PBI) was prepared as thin coatings on aluminium substrates at different final curing temperatures. Their tribological properties were tested at room temperature in comparison to coatings made of polyamideimide (PAI), using various test methods. The adhesion to the substrates was best for PBI processed at a final curing temperature of 280°C. This was also reflected in a better scratch resistance, whereby in all cases PBI was superior to PAI. The same was true for sliding wear of the coatings against smooth steel counterparts. Under abrasive wear against sand paper, the friction and wear values were lower for smaller abrasive grains, but no remarkable differences were visible between PBI and PAI, regardless of the curing temperature.Polybenzimidazole (PBI) was prepared as thin coatings on aluminium substrates at different final curing temperatures. Their tribological properties were tested at room temperature in comparison to coatings made of polyamideimide (PAI), using various test methods. The adhesion to the substrates was best for PBI processed at a final curing temperature of 280°C. This was also reflected in a better scratch resistance, whereby in all cases PBI was superior to PAI. The same was true for sliding wear of the coatings against smooth steel counterparts. Under abrasive wear against sand paper, the friction and wear values were lower for smaller abrasive grains, but no remarkable differences were visible between PBI and PAI, regardless of the curing temperature.

We extracted natural Eucommia ulmoides gum and studied its application in natural rubber tire compounds in this paper. The result showed that addition of Eucommia ulmoides gum could improve the properties of Natural rubber tire compounds greatly.We extracted natural Eucommia ulmoides gum and studied its application in natural rubber tire compounds in this paper. The result showed that addition of Eucommia ulmoides gum could improve the properties of Natural rubber tire compounds greatly.

Chitosan is natural polymer that has non-toxic properties, biodegradable and biocompatibility material. This study aimed to investigate the effect of chitosan as antitermite in papermaking. The effectiveness of chitosan as antitermite was determined by measuring weight loss of cellulose paper. The concentration of chitosan used in this study was varied from 1% to 5%. Chitosan was dissolved in 1% acetic acid and then applied it to paper sample with soaking treatment. They were exposed to subterranean termite for two weeks. The effectiveness of chitosan were evaluated by determining the weight loss of paper. The results showed that concentration of chitosan solution affected the weight loss of paper. As concentration of chitosan increased, the percentage of weight loss decreased. This study indicated 3% of chitosan as optimum concentration and chitosan was effective as biotermicide in papermaking. Chitosan has potential to be used as antitermite in paper making.

Aerobic composting technology is an effective solution to treat organic waste. Sludge, as one kind of organic waste, the traditional way to treat is to dewater it to less than 80% mositure content and use for aerobic composting, which may cause the problems like low fermentation efficiency, serious odor and large area. In this paper, municipal sludge is compressed and dewatered to about 60% moisture content, then aerobic composting is carried out with organic waste such as domestic waste, and the fermentation period is reduced from 30 days to about 20 days. The composting system is basically odorless, and the area of composting system is reduced by more than 50%.

This paper describes the reaction mechanism to deposit pyrolytic carbon within porous body of char derived from oil palm empty fruit bunch (EFB) via an integrated pyrolysis-tar decomposition process, which employs chemical vapor infiltration method. This process was developed to produce a value-added EFB-derived char and to make EFB able to be utilized as a supplementary solid biofuel. The product, namely carbon-deposited char, was characterized in comparison with metallurgical coke breeze used in iron-steel industry.

Demand for fossil fuel of coal, petroleum and natural gas has always increased from year to year. Therefore, the development, expansion and utilization of biomass from non no-fossil fuels need be carried out. Efforts to explore, develop, process and utilize biomass from non-fossil fuels, which is the cultivation of microalgae containing triglycerides that can be extracted into methyl esters (biodiesel). The sample extraction process is carried out in 5 stages, such as harvesting, weaving, methylation, extraction, and washing. The amount and ratio of saturated and unsaturated fatty acid is a key that determines the suitability of microalgae as a biofuel feedstock. This paper aims to compare the potential microalgae in Indonesia with the other countries as feedstock for biofuel production. The fatty acid composition of Synechococcus sp. HS-9, Spirulina platensis, Glagah consortium microalgae, and Nostoc HS-20 from Indonesia could be a promising feedstock for biofuel production. The quantity of fatty acid microalgae from Indonesia higher than the other countries.

The present study was carried out to beneficiate coal tailings sample using froth flotation technique. The aim of the investigation was to remove the carbonaceous material present and to reduce the environmental pollution generated through large volume of tailings from a coal preparation plant. The characterization studies show that the sample contains D80 passing size as 276 µ and D50 as 182 µ. The proximate analysis indicated that the coal sample contains 45.3% ash and 34.5% fixed carbon. Froth flotation experiments were carried out at varying parameters of collector dosages (0.60, 0.67 & 0.71 kgpt), frother dosages (0.33, 0.44& 0.51 kgpt) and pulp density (8%, 10% & 12% w/w). The experimental results indicated that the optimum amount of clean coal may be recovered from tailings with an ash content of 18.46% in the clean coal with an appreciable yield of 64.13%. The optimum results were obtained at frother dosage of 0.44 kgpt and collector dosage of 0.60 kgpt with pulp density of 10% (w/w).

Dewatering and drying is one of the important parts in municipal sludge treatment and disposal. In this paper, the sludge rapid dewatering process was studied and put into simulation in sewage treatment plant in pilot scale. The advantages of the two processes of “gravity concentration + conditioning press” and “mechanical concentration + conditioning press” were compared, and the formulation of conditioning reagent was selected and optimized. Compared with gravity concentration, mechanical concentration efficiency is higher. Adding the filtering reagent B had the advantages of high dry-base treatment efficiency, neutral pH and low moisture content after dewatering, which met the requirements of moisture content and pH for subsequent aerobic composting. Finally, the stability of this process and its system were further tested verified in practical production.

Black liquor from paper pulp industry contains lignin and spent pulping chemical. Conventionally, it is combusted in a recovery boiler to utilize the heat energy for steam production and for power generation. The steam is utilized in the pulping process. To improve the efficiency of power generation, a gasification process is proposed to replace the combustion process. However, it is still under research and development stage. Concentrated black liquor fed to the recovery boiler or gasifier usually has a solid content about 60 – 80%. Therefore, significant amount of water is still in the liquor and may impact the combustion or gasification process. In this work, the drying rate and early stage of devolatilization of concentrated black liquor is studied using DTA/TGA equipment. The experiment will be conducted in nitrogen atmosphere from room temperature up to 300°C. The heating rates that are used are 5, 10, 20, and 30 °C/min. From the experimental data, the drying and devolatilization stages can be distinguished. In this study, the drying kinetic is modeled using five semi empirical model. The models can give good fitting with the experimental data. The second stage, or devolatilization, comprised of the evaporation of the remaining moisture together with pyrolysis reaction. The kinetic analysis of the devolatilization reaction is performed using Distributed Activation Energy Model (DAEM).

The use of two stage anaerobic reactors is intended to separate the hydrolysis process and the acidogenesis process from the methanogenesis process, thus allowing optimization of different operating conditions in each of these processes. With such optimization, this reactor has some advantages in processing the complex substrate compared to a single stage anaerobic reactor, especially when the substrate has high fat content, such as palm oil mill effluent (POME). The purpose of this research is to get the strategy of separating the acidogenesis process from methanogenesis process, with pH adjustment and air injection. The experiments were run in 8 batch reactors with each working volume of 500 mL. Each reactor was filled with 10 mL aqueous glucose solution with the concentration of 1.5 g/L as the ideal substrate, 5 mL of aqueous Na2CO3 solution with 1.5 g/L concentration as buffer, and 400 mL of inoculum. Four of the reactors were adjusted to pH 4, while the other four reactors were set on pH 5. In each pH variation, two reactors used biodiesel waste inoculum, while the other two used cow manure inoculum. Prior to data collection, all reactors were flushed using a mixture of 85% v/v N2 and 15% v/v CO2 to ensure zero oxygen environment. For every inoculum type, one of the reactors was run as a completely anaerobic reactor, the other was run with periodic injection of air 10 ml/day. The results showed that separation of acidogenic/acetogenic and methanogenic stages in anaerobic digestion could be conducted effectively by pH adjustment and controlled air injection. With air injection, pH value was not significantly essential for suppressing methanogenic activity as oxygen presence will inhibit methanogenic microbes and the pH will automatically drop as VFA start accumulating. The information presented in this paper is quite useful to define further study in manipulating the performance of anaerobic microbial consortium. Although this consortium is widely known as syntrophic community, which will be difficult to isolate each species in the community, it is still possible to enhance the dominance of one stage (acidogenic/acetogenic) over the other (methanogenic) by controlled air injection.

The concept of using network centrality measures in the selection process of memetic differential evolution algorithm is proposed. The usual aim for introducing changes in global optimization algorithms is to make it perform better. This short paper does not intend to provide enough experimental details to decide upon the performance of the new method, nevertheless, we definitely obtain interesting insights on how the discovery of local optima were done.

The improvement of air pollution issues and excessive road transportation dependence on crude oil is not possible today without the implementation of new mobility concepts, preferably complying with the principles of sustainable social and economic development. The lack of these concepts, as emphasized in the White Paper, Roadmap to a Single European Transport Area – Towards a competitive and resource efficient transport system, will preserve transportation dependence on crude oil so deeply that only 10% of energy will be derived from renewable sources. According to this scenario, until 2050 the CO2 emissions in the transportation sector will increase by one third compared to 1990. Moreover, there will be an increase in the costs of traffic congestion until 2050 by ca. 50%. The difference in availability between central and peripheral areas and social costs of accidents and noise pollution will increase as well [1].

Nitrogen is the most important substance in fertilizer to produce high quality harvest. Nitrogen, which comes from the air, can formed as ammonia and nitrate in fertilizer. In industry, the most common fertilizer contain ammonia not nitrate because of its production process easiness compared to nitrate. Ammonia has fertilization efficiency 40% and nitrate has fertilization efficiency 60%. Industrial fertilizer production process nowadays, ammonia synthesis which called Haber-Bosch process, still not environmental friendly and also consume high energy. Environmental friendly and lower energy process is needed to produce fertilizer. Some study related to nitrogen fixation to produce fertilizer has been made including plasma electrolysis method. Plasma electrolysis is an effective method to fix nitrogen from the air because of its ability to produce OH radicals and other radicals to break the N2 bound to produce nitrate with lower energy consumption compared to Haber-Bosch process. This method is implemented in batch reactor with variation of anode depth. This study has proven can produce nitrate up to 1,200 ppm in condition power 800 watt, anode depth 1.5-3.5 cm and Na2SO4 electrolyte concentration 0.02 M.

Driven by the exacerbating urbanization and population, there has been a shoot up in the global energy demand over the past few years. The technological exploration efforts in the field of biofuels have proven to be a promising alternative to the slumping fossil reserves. The main aim of this work is to inspect the potential of palm oil as a biofuel with aluminum oxide nanoparticles as an additive in it. The experimental work was carried out on a single-cylinder four-stroke CI engine running at a constant speed of 1500 rpm at varying loads using palm oil biodiesel blends and the emissions and performance parameters were compared with that of neat diesel. The results concluded a significant increase in BTE with increase in alumina concentration in the blend owing to catalytic behavior of alumina which accelerates the combustion process. Furthermore, reductions in HC and CO emissions were also recorded.

Recently, there has been considerable attention in the development of biodegradable plastic. Our current use and disposal of synthetic-based conventional plastics caused high rates of land-fill problems because of its persistence in the environment. Many renewable resources have been used as a source of starch and cellulose as bioplastic constituents. One of the most available biomasses that have not been explored is water hyacinth (Eichornia crassipes). In the present study, we investigated the fabrication of biodegradable plastic made with a matrix of 3% and 5% mixture of starch and cellulose extracted from water hyacinth in different weight ratios of 10:0, 9:1, 8:2, and 7:3. The addition of water hyacinth cellulose was purposed as a reinforcing agent to improve the performances of the starch bioplastics. Chitosan with a matrix of 1% was also added to improve the mechanical function of starch bioplastic. There were two main steps performed to isolate water hyacinth cellulose, i.e., bleaching and alkali treatment. The chemical and physical characteristics of starch-based bioplastics and their composites were then analyzed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Moreover, the tensile strength and bioplastic degradation tests were also conducted to study the performance and biodegradability. The FTIR data shows that the functional group’s absorption revealed corresponds to the pure cellulose indicating the successful cellulose isolation from water hyacinth. The tensile strength of bioplastic starch- chitosan increases with the addition of water hyacinth cellulose. The improvement of the physical properties of bioplastic starch was achieved through the addition of chitosan and water hyacinth. The mixture of starch-chitosan combined with water hyacinth cellulose produces environmentally friendly bioplastics shown by the increased mechanical and physical properties compared to starch-alone bioplastic.

Photobioreactor have been a prominent way to produce biomass in case of biofuel production. One of the most important procedure in this line of production is harvesting. Nowadays, microalgae biomasses are harvested by using many methods such as flocculation, filtration, centrifugation, and the other methods. Those methods are the commonly used by many bioenergy companies to accumulate their biomass before extraction phase. This process requiring a lot of cost and times. In order to increase cost and time efficiency, examination of ultrasound wave trapping method has been done. A harvesting module was assembled as a system consisted of two piezoelectric circuit (ultrasound wave generator) in a transparent box. Data shown by generating 1.7 MHz wave for 20 minutes, turbidity of Synechococcus (coccoid cyanobacteria) biomass was decreased from 56.3 NTU to 55.6 NTU. The other data also shown decreased turbidity of mixed culture biomass from 46.5 NTU to 16.4 NTU. This results also followed by weight measurement for both biomasses. This module capable to accumulating microalgal biomass a number of 0.0138 gram for Synechococcus and 0.8544 gram for mixed culture. The difference in biomass accumulation results are caused by cell size and density. Synechococcus cell size range between 0.5-2 µm with a very low density. This phenomenon makes any kind of small-sized coccoid cyanobacteria are need more time to be accumulated. Meanwhile mixed culture of microalgae is easier to accumulated due their variety of size and density.

Activated carbon is one of the solutions to overcome the cigarette smoke problem where durian shell waste is chosen as the base material. Durian shell waste is chosen because it has a high cellulose, lignin and starch content, plus its production reaches 746.805 thousand tons per year. Activated carbon from Durian shell waste will be firstly processed with cleaning, drying, and semi-carbonizing at 200°C for 3 hours with 12.5% yield. The step continued with chemical activation by K2CO3 with variations in impregnation, which are 1:1, 3:2, and 2:1. Next, the activated carbon is physically activated by using a temperature of 600°C with N2 stream of 200 ml/min. Activated carbon as a result of activation and modified activated carbon are then characterized by Iodine Number test and SEM test. As a result, activated carbon with K2CO3 3:2 had the largest iodine number with 414.43 mg/g and after it was physically activated, the 3:2 variation was still had the largest iodine number with 579.49 mg/g.

This research aimed to determine the effects of catfish meat addition to the fulfillment of protein and vitamin A (beta-carotene) and to study physicochemical properties (density, iron, beta-carotene, and proximate) in instant baby porridge using the drying method of the freeze dryer. Fish meat is added to fulfill the content of instant baby pulp protein in accordance with SNI. Baby porridge is dried using a freeze dryer tool which then becomes a form of instant baby pulp. The baby porridge sample was compared with baby control porridge (without fish meat addition) which was the result of previous studies. This research used a completely randomized design with one factor, namely variation in the percentage of catfish as 7.5%, 10%, and 12.5%. The results showed the addition of catfish meat with variations in the concentration of fish meat influenced the nature of the content both physically and chemically. The best baby porridge in terms of chemical properties in meeting the needs of protein and vitamin A (beta-carotene) was found in instant baby porridge with 10% concentration of catfish meat for protein and baby porridge and 7.5% concentration of catfish meat for vitamin A. The addition of catfish meat provided good chemical properties than control sample.

Successful research has been done to extract oil from Ketapang seeds that are converted to biofuel. The method used is Soxhletation and evaporation to get Ketapang seed oil which is continued with conversion to biofuel by catalytic hydrocracking method. Characterization of ZnO catalyst was performed by XRD instrument. From this study, it was found that Ketapang seeds can produce oil by 50.2% and after being tested with the GC-MS instrument found that Ketapang seed oil contains several compounds such as palmitic acid, ethyl oleate, etc. From the content, it can be concluded that Ketapang seed oil can be converted into biofuel. Biofuel produced through catalytic hydrocracking stages using ZnO with a ratio of 10:1 between Ketapang seed oil and catalyst which is seconded by hydrogen gas flow rate of 30ml/minute. The oil conversion results in the form of light and heavy fractions of gasoline such as n-hexane, heptane, octane, nonane, decane, undecane and, dodecane.

Cement plays a major role in the production of paver blocks. Cement manufacturing industries pollutes the surrounding areas. The main objective of this work is to reduce the use of cement in the concrete paver block by partial replacement with rice husk ash. An experimental investigation is conducted to analyze the compressive strength, water absorption and flexural strength of paver blocks with partial replacement of cement by rice husk ash dumped near Chengapalli, Tiruppur. Rice husk ash were collected from the dump yard and utilized for experimental investigation after doing the initial cleaning process and property study of material. Cement replacement with Rice husk ash were done in proportions of 10% 20%, 30%, 40% and 50% in volume of concrete. Various strength parameters like compressive strength, flexural strength and water absorption were determined. Weight of concrete blocks is considerably reduced with increase in the amount of rice husk ash.

Gasoline used in an Otto engine can be substituted by pure Bioethanol or Gasoline-Bioethanol blends. The engine performance can be affected by the mixture. Specifically, the blends can affect (Increasing or decreasing) power, torque, and emission produced by the engine. It is caused by the different characteristic of the Gasoline-Bioethanol blends depending on the volume percentage of the Bioethanol. Theoretically, as the increasing of the volume percentage of Bioethanol to the mixture, the power and torque produced would be decreased because of the lower energy contained rather than gasoline. As a biofuel, Bioethanol is a natural product and created by the fermentation of plants containing sugar and starch which has a similar physical and chemical characteristic to gasoline. The objective of this experiment was to determine the effect of Bioethanol-gasoline blended fuels on the performance of an engine. In this case, the performance includes specific fuel consumption, power, and torque. The experimental test was using gasoline with octane number 88, 92, 98, and 30%, 40% Bioethanol blend. The effect carried out by increasing the volume number of Bioethanol to the gasoline is the increasing of the power and torque produced by the engine. Keywords: Gasoline, bioethanol, research octane number, engine performance.

Wastewater of the laterite hydrometallurgy process which still contains nickel more than 0.25 % and other metals. One method which able to treat wastewater is the electrocoagulation process. In this work, the electrocoagulation process using batch recycle methods has been successfully coagulated nickel and other metals from the wastewater of the laterite hydrometallurgy process. In this work, a tubular aluminum electrode was used in the electrocoagulation reactor. Sodium hydroxide is used to increase the pH of waste. Taguchi design of experiment has been used to analyze and optimize the electrocoagulation process using batch recycle methods. Taguchi analysis results show that the optimum conditions are at 21 of voltage, 5 of pH, 5 hours of time operation, and 0.53 liters/minute of flow rate.

The adverse environmental degradation created by various plastics produced from petroleum products is a major concern for the world nations. The developed and developing nations have adopted various strategies on the production and usage of highly hazardous conventional plastics. Various research works have been undertaken to formulate a sustainable alternative for the conventional plastics. In this regard, an effort was made to synthesis a biodegradable polymer for large scale commercial usage in packaging applications. Biodegradable polymers can be produced from various resources. The study involves the production of bio-plastic from Banana peel and Prosopis juliflora. Cellulose, a major component required for biopolymer synthesis was extracted from Prosopis juliflora which then combined and processed with dried banana peel. Additives and preservatives that contributes to the polymer characteristics were added in suitable proportions and processed under defined conditions. The mixture was then dried at a temperature of 130 ℃ to yield the final product. The biopolymers thus produced were tested for its water absorption capacity, thermal resistance, tensile strength, biodegradability and microbial attacks. It was observed that water absorption capacity of the biopolymer was lower for lesser starch and higher cellulose concentrations. The tensile strength was found to be 0.67 N/mm2 which was due to the addition of zinc oxide. No microbial attack was observed during storage and it was also found that the biopolymer was able to withstand high temperature up to 130 °C during its usage.

The level consumption of Polyethylene Terephthalate (PET) as a packaging of colored beverage bottles occupies the fourth largest in the world. In Indonesia, PET consumption increased reaches 7% per year so that it can cause environmental impacts. This study aims to process the recycling PET waste by obtaining a simple potential process to remove the color from PET waste. The decolorized PET waste will be an alternative carbon source for Carbon Nanotube (CNT) synthesis. The colors of PET waste are blue and green bottles. The selected color removal agent is hydrogen peroxide (H2O2) because it is inexpensive reagent and has lower toxicity to environment. The colored PET waste and H2O2 will be heated in the oil bath system at temperature 110°C and pressure 1 atm. The result showed that color removal time for blue PET waste faster than the green PET waste, 72 and 115 minutes per 15 grams PET waste. The quality of color removal of blue PET waste is better than the green PET waste because it has a reflectance value closer to colorless PET waste, namely 80%. The CNT synthesis process from decolorized blue PET waste produce 8.58% yields. The average diameter of CNT crystals from its process is obtained at 37 nm. This shows that PET waste plastic which has been discolored can be used as a carbon source in CNT synthesis.

Maharashtra Industrial Development Corporation (MIDC) has established in Navi Mumbai region an industrial estate which spreads over 2562 hectares with about 3,450 industries. The industrial units cover various categories such as textile, chemical pharmaceuticals, dyes, pesticides and plastic moulding and fabrication, foundry etc. with varying sizes. All the major & medium industries have provided full-fledged effluent treatment plants and the small industries have only primary effluent treatment units. Thane Belapur Industries Association initiated and promoted formation of Common Effluent Treatment Plant (CETP) with 12 MLD capacity in 1997, which was further expanded to 15 MLD in 2006. The partially treated effluents from the industries are carried through closed pipelines to CETP for further treatment. In the present study, treatment efficiencies of CETP at the outlets of primary and secondary stages were determined based on one-year data. Analysis of values of BOD, COD and TSS at discharge point conform to the discharge standards of Maharashtra Pollution Control Board (MPCB) throughout the year.

Disposal of untreated waste in the environment leads to the creation of harmful diseases, greenhouse gases and climate change. So the demand arises to eliminate or avoid these kinds of risks to both the society as well as environment. Because of this there are enormous solutions and ideas that are playing a crucial role in this risk avoiding activity. In this study, adsorbent has been synthesized by hydrothermally treating the horse manure. The effect of this synthesized adsorbent produced from horse manure was studied for the removal of toxins like methylene blue, ethyl orange, azo dyes and crystal violet dyes which is presented in the textile effluent. These dyes can create severe illness to both the people as well as aquatic species while it is mixed with natural water bodies.

The increasing of scarce of petroleum availability, unstable prices, and potential environmental damage due to the use of fossil fuel encourage the development of alternative fuels that can replace fossil fuels, including jet fuel. Bio-jet fuel is a renewable fuel that has similar characteristics to jet fuel. The potential raw material for bio-jet fuel production in Indonesia is coconut oil. The composition of fatty acids in coconut oil corresponds to the range of carbon atomic chain of jet fuel. Indonesia is also the country with the second-largest share of coconut oil exports in the world which shows that the use of coconut oil in Indonesia is very less. In this study, bio-jet fuel was synthesized from coconut oil through hydrodeoxygenation reaction to convert fatty acids to hydrocarbons by removing oxygen. The catalyst used in this reaction was NiMoP/Al2O3 catalyst. The hydrodeoxygenation reactions were carried out with variations of pressure and temperature, at pressures of 10, 15, and 20 bar, and temperatures of 375, 385, and 400°C. The reactions were stopped if they had reached equilibrium based on GC-TCD analysis of the gas product. The hydrodeoxygenation reaction at 400°C and 20 bar was able to produce high conversion (92.56%), much hydrocarbon content (91.91%), high selectivity and also yield of bio-jet fuel (82.93% and 54.34%). Liquid products were distilled to obtain jet fuel fraction products. From the results of the density, viscosity, acid number, heating value, and freezing point analysis of the bio-jet fuel distillate, good values were obtained.

Biogas is one of promising renewable fuel produced from several numbers of organic substrates. In fact, biomass as the organic matters has an opportunity to generate a cheaper and cleaner energy than using other resources. Therefore, many researchers have been studied about the production of biogas from various kinds of biomass. In Indonesia, there are many cows and lemongrass in nature. Therefore, this study is focused on the utilization of cow manure and lemongrass as the substrate for the production of biogas. The purpose of this study is to obtain the optimum condition of biogas production, including composition of the substrate and temperature of the bio digester. Besides, the addition of rumen bacteria was also investigated in this study. The composition of cow manure and lemongrass were varied at the ratio of 1:0, 3:1, 1:1, 1:3 and 0:1 in weight. The temperature of bio digester was also varied at room temperature, 39℃, and 50℃. Result shows that the volume of biogas produced by using lemongrass was less than using cow manure. However, the mixture of cow manure and lemongrass improved the quality and quantity of biogas produced. Based on the results, the highest volume of biogas at 890 mL and the highest percentage of methane at 14.90 % were produced from the composition of substrate with the ratio of 1:1 at the temperature of 50℃ with the addition of rumen bacteria. It was revealed that the higher temperature of bio digester was better for the production of biogas in the range of room temperature to 50℃. It was also proved that rumen bacteria are important for the production of biogas.

Batik industry in Indonesia frequently dispose liquid waste containing high level of toxic and carcinogenic dyes to the drainage without being treated. In accordance with it, plasma electrolysis has been proved as the efficient method to degrade dyes waste, yielding higher hydroxyl radicals than other methods. The experiment was conducted by generating plasma in circulated reactor using stainless steel cathode and tungsten anode with 2 cm depth immersed in 0.02 M Na2SO4 electrolyte solution added by 20 mg/L Fe2+ and 100 mg/L of Remazol Red initial concentration, with addition of varying air injection rate at maintained power. The results show that 1 L/min is the optimum air injection rate value to operate this reactor effectively at 450 W of optimum operating power so that it could lower the breakdown voltage, reduce energy consumption, produce more OH radicals and other reactive species, and elevate the degradation percentage. The experiment conducted in optimum operating condition provide result of 99.61% in degradation percentage for 60 minutes with final concentration of dye is 0.39 mg/L, 41.55 mg/L of COD, and 3177.16 kJ of energy consumption.

Quality control of cocoa is an important matter to ensure safe consumption of cocoa products. Conventional elemental analysis of cocoa beans uses chromatography that requires extensive sample preparations. This poses a problem for Indonesian cocoa farmers who have limited resources. Laser Induced breakdown Spectroscopy (LIBS) is one of the best techniques for elemental analysis owing to its distinct features such as inherent rapidity and simple sample preparation methods with small quantities of samples. This means that LIBS can be used as an alternative technique for elemental analysis of cocoa beans. We report a study of elemental composition of fermented cocoa beans from Flores Island, Indonesia.

One of the main factors that cause the earth that we live in is not as clean as it was before is the utilization of fossil fuel. Motorized vehicles still utilize fossil fuel as energy sources, and the number of motorized vehicles is growing every year. Biomass energy are one of the alternative energies currently being developed. Bioethanol are one of the technologies for fuel in motorized vehicles to utilize biomass as an alternative energy. The addition of bioethanol to gasoline will certainly change the fuel properties, the fuel will be more difficult to self-ignite so the pressure generated in the combustion chamber will be more consistent. Coefficient of variation (COV) represent the ratio of the standard deviation to the mean of a set of data, in this study in cylinder pressure data (IMEP) is used. Based on previous research that discussed the analysis of emission gas and fuel consumption on SI engine fueled with low-grade bioethanol and oxygenated additive, the authors examined further to analyze the characteristic of ethanol blend and oxygenated additive to COVIMEP and Heat Release Rate (HRR) of various fuel mixture as well as COVIMEP correlation with HRR at variable engine speed were investigated. The result show that compared with pure gasoline, ethanol blend decreases HRR. When oxygenated additive added to gasoline – ethanol blend, it increases its maximum heat release rate especially on fuel mixture E5 about 6.2% compared to E0. And the Correlation of COV and HRR; as COV value increases, HRR decreases. Whereas, when COV value decreases, HRR increases.

Microbial Desalination Cell (MDC) is a developed technology for reducing salt concentration of seawater, so it could be used for people’s daily needs. Since there were many tofu industry in Indonesia, so that the substrate in this research came from model of tofu wastewater. For increasing MDC performance, there was modification in reactor design, whereas the IEM (Ion Exchange Membrane) was arranged in two stacked design, yet in the end of desalination cycle there was a recirculation through anolyte-catholyte solution to maintain pH level. The variations of flowrate recirculation were 0.5 and 5 mL/ min. The result showed that the optimum flowrate for anolyte-catholyte recirculation was 0.5 ml/minute with TDR (Total Desalination Rate) of 2.447 g/h and it showed that recirculation process could increase the salt removal of desalination process.

Biogas has been one of the promising renewable fuel produced from organic substrates. Cocoa husk has a potential to be a substrate for biogas production. Based on various studies, cocoa husk has the potential as a substrate for methane production from anaerobic co-digestion. However, lower biodegradation efficiency of anaerobic co-digestion of cocoa husks was affected by high cell wall content of cellulose and association between cellulose and lignin, which would hinder the anaerobic microbes to convert cocoa husk into methane. Cow rumen fluid has been proposed for method for biodegradation of lignocellulosic biomass, since it has advantages in degradation of plant material by the Fiblolytic enzymes from the rumen ecosystem. The ratio of cocoa husk to cow manure are as follows, 1:3, 1:1, 3:1, and 1:0, where the substrate used for all four variations is 100g, the variation of substrate to cow rumen fluid is also applied with the following ratio 1:1, 1:0, 2:1, 1:2, and incubation operating temperature is as follow 25°C, 37°C, 50°C, and 70°C. This research would see the potential of cocoa husk as a substrate, and the effect that will happen if cow rumen fluid is used as its inoculum, and to know if there is an increase in efficiency of digestion, in form of higher solids degradation and higher biogas methane composition. The purpose of this research is to know the optimum ratio between cow manure and cocoa husk and feasibility of rumen fluid as inoculum. Based on the results of the research, the following can be concluded: The optimum ratio of cocoa husk to cow manure is 1:1, the optimum ratio of substrate to cow rumen fluid is 1:1, and the optimum temperature for biogas production incubation is 37°C or mesophilic condition.

In order to improve the quality and the separation effect of CO2 in X gas field, the influence of swing on removing of water content on purification of CO2 from offshore natural gas by pressure swing adsorption (PSA) and triethylene glycol (TEG) absorption was investigated by simulation. This method is to reduce the water content in the CO2 gas for enhanced oil recovery (EOR) method. In the EOR injection process at Y oil field, the purity of CO2 is more than 95%. The purity of CO2 plays an important role in determining the amount of oil that can be recovered. In system using PSA, the mass of activated carbon is needed of 11,555.3 lb/day, whereas by TEG absorption is required 91.27 gpm TEG adsorbent. Economic analysis was also carried out based on the oil yield that can be recovered from well (20.53 MMstb) using CO2 from X gas field for EOR injection in Y oil field. In PSA integrated system showed net present value (NPV) of 349,376,372.23 $ US, internal return rate (IRR) of 19.87%, with an investment cost of 214,918,114 $ US. The system integrated with TEG dehydration has an NPV of 390,869,013.8 $ US, IRR of 20.37%, and an investment cost of 240,111,000 $ US. These results showed that CO2 purification from X gas field is the most optimal and efficient when the system used the TEG absorption with NPV of 423,392,895.6 $ US, IRR of 20.71%, and payback period of 4.06 years. Based on the results of comparisons between the PSA and TEG features of upgrading technologies of CO2 in X gas field, the specific requirements for CO2-EOR in Y oil field, recommendations are made regarding appropriate technology for CO2−EOR

The impact of emerging agriculture as the dominant sector in Indonesia was abundant in agricultural waste such as rice husk and rice straw. Slow pyrolysis was proposed as processing treatment of residue to get bio-char and bio-oil at 250 °C using a simple stainless-steel reactor. The selected temperature for the pyrolysis process based on TGA result and the optimum condition of the combustion process. Bio-char produced was 57 wt% which porosity range around 50 µm identified from SEM image, which could be used as bio-sorbent materials. While bio-oil has phenol as a dominant compound known with its bactericidal activity. Based on IR spectrum, the pyrolysis process only reduces the small amount of water and organic compound of biomasses. Even though from physical appearance after the pyrolysis process both biomasses become different, but from SEM image, pyrolysis process did not change materials structure excessively. The impact of the pyrolysis process on rice husk difference with rice straw because of its chemical compound and also size of materials.

Coal consumption in the Indonesian metallurgical industry in 2015 has reached up to 3.5 million tons. One ton of pig iron required 0.5-0.6 tons of coke, 1.4 tons of iron ore, and 0.25 tons of limestone. Coke added by the charcoal is called bio- coke. Charcoal, as the raw material of coke from the carbonization process of Indonesian redwood residues, can reduce the consumption of coking coal. Biomass has been applied as an alternative renewable fuel to the industrial sector to reduce CO2 emissions. The use of biomass reduces the dependence on traditional fossil fuels whose resources are reduced every day. The purpose of this study was to obtain the best charcoal sizes from redwood and improve the quality of bio-coke through the dry cooling process. The final method of bio-coke can be done coke dry quenching to prevent the occurrence of cracks in the coke, increase coke strength, and less chemical activity during cooling. Redwood charcoal with particle size (10, 25, 50, and 80) mesh is blending with coking coal. The mixing, composition of coal with redwood charcoal is 90:10. Blended briquettes with the addition of molasses and wood tar are processed by re-carbonization at 1100 °C for 4 hours. Bio-coke charcoal 50 mesh has bulk density of 1071.44 kg/m3. The strength of bio-coke increases as bulk density increases. The maximum size of the redwood charcoal particles of the study on 50 mesh generated a compressive strength of 4.87 MPa.

Today, microalgae have been attracting as promising raw material for biofuel production. Hydrothermal liquefaction is a proposed technology to convert microalgae biomass into liquid fuels, called bio-crude oil. This study investigated the effect of biomass weight-water volume ratio (1:20, 1:30, 1:40), temperature (200, 225, 250 °C) and residence time (10, 20, 30 minutes) on bio-crude oil yield of non-catalytic hydrothermal liquefaction from Indonesian microalgae Skeletonema sp. The highest bio-crude oil yield was 2.20%, obtained at at biomass weight-water volume ratio of 1:20, temperature of 250 oC and residence time of 10 minutes. The highest component of bio-crude oil was hydrocarbon (37.20 %). The low product yield was caused by the longer process residence time (especially in cooling step), low amount of carbon-hydrogen content and high amount of oxygen-ash content in biomass.

The pyrolysis characteristics and kinetic parameters of coal and water hyacinth blend have been investigated by using thermogravimetric analysis. Those of pure coal and pure water hyacinth were also each studied as a comparison. The coal sample was taken from a Sub-district of Gunung Panjang, Berau, East Kalimantan, Indonesia. The as-received sample was ground to be a mesh size of 60. The sample of water hyacinth originated from Dams of Selorejo and Sengguruh, district of Malang, Indonesia. The raw material was cleaned with water and subsequently cut and dried at the temperature of around 85 °C for 6 hours. The dried biomass was then crushed and sieved at a size of 60 mesh as well. The blended fuel was composed of coal and water hyacinth in a mass ratio of 40:60 (wt%). The thermogravimetric experiment was performed for the coal, the water hyacinth, and their blend under the instrumentality of thermal analyzer at a single heating rate of 40 °C/min. The sample was heated up from 27 to 1000 °C with a nitrogen flow rate of 100 ml/min. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves were obtained. The kinetic evaluation was performed under the fitting method of Coats-Redfern. The results indicated that three stages of decomposition process were encountered during thermal degradation of the individual samples of coal and water hyacinth, as well as their blend. The addition of 60% water hyacinth to the coal provoked the thermal degradation toward the lesser temperature and forced the increase of maximum mass loss rate. The activation energy went to decrease together with the increasing of water hyacinth fraction, i.e., 84.02, 66.72, and 44.45 kJ/mol for respectively the coal, blended fuel, and water hyacinth. These results could be valuable in designing and developing of the reactor of the thermal conversion system on an industrial scale.

Present scenario requires methods for treatment of industrially waste water polluted with hazardous chemicals and dyes. This work reports efficient utilization of nano-ceramic ‘hydroxyapatite’ for degradation of Indigo Carmine dye present in waste water under ultra violet light illumination. The photo-catalytic experiment is carried out via artificially polluting water with Indigo Carmine dye at three different dye concentration (5, 10, and 20 mg/L) in presence of hydroxyapatite nano-powder (25 mg). After 180 min ultra violet light illumination, almost 63, 61 and 43 % dye degradation is observed in above dye solution. Treatment of such dye polluted water is necessary for making it usable water for society and for the development of sustainable ecosystem.

There is a lot of energy potential in biomass wastes in Indonesia, and one of those is rice husk. This research will create a suitable model for drying and pyrolysis zones in rice husk gasification. The single particle model is chosen as the model since it can help to observe conversion happened within a particle in detail. This is important because with that, we can understand the compositions of pyrolysis gas, char, and primary tar in drying and pyrolysis zones in rice husk gasification. To validate the model, air flow rate is chosen as the variable that would be varied. The objectives of this research are to check whether the model is suitable for modelling drying and pyrolysis zones in rice husk gasification as well as to understand the effects of air flow rate in the product compositions using the simulation. The results show that the primary tar content is increasing by the increase of air flow rate, while the pyrolysis gas content is decreasing, and the char content is constant. The results show that the numerical model is considerably suitable for modelling drying and pyrolysis zones in rice husk gasification.

The research which had been conducted in March–June 2019 had the purpose of determining the effect of water spinach (Ipomoea aquatica) on BOD and COD levels in Krebet Sugar Mill wastewater with phytoremediation technique. The research used the posttest-only control group design. Liquid waste experiments were taken at three points on the waste stream using water spinach (Ipomoea aquatica) with three repetitions. Data analysis using statistical description by comparing each data obtained from the treatments with controls. The results of the study showed that the Krebet Sugar Mill wastewater treatment using water spinach plants (phytoremediation technique) was able to reduce BOD parameters by 5.49 mg/L at the first point; 2.53 mg/L at the second point; and 5.20 mg/L at the third point; while COD parameters was 7.79 mg/L at the first point; 12.56 mg/L at the second point; and 12.15 mg/L at the third point. The conclusion of this research is the phytoremediation technique using water spinach plants influential can reduce the levels of BOD and COD in liquid waste.

The study of nanocellulose has been emerging due to its highly possible applications. The main objective of this research is to fabricate nanocellulose crystalline filament from Sugarcane Bagasse through wet-spinning method. Sugarcane Bagasse is chosen due to its abundance in Indonesia and high cellulose content. In this research, the Sugarcane Bagasse were mechanically treated in order to minimize the size. Secondly, the biomass is pre-treated with NaClO2 (Bleaching) in order to eliminate lignin and hemicellulose. Thirdly, the biomass is treated with Acid Hydrolysis. The variation used in Acid Hydrolysis is HCl with 1%, 3%, and 5%. After obtaining Nanocellulose Crystalline, the biomass was spun through wet-spinning method using 16G needle, 18G needle, 1.5%, and 2% in concentration as the variation. The wet spinning method used a coagulating bath that is filled with Acetone. The characterization used in this research would be Cellulose Content Test, TEM, XRD, and Tensile Strength Test. The average results of this research are 42.75% on cellulose isolation, 63.9% on CNC crystallinity index, 45.3 nm on particle size, and 4.3 lbs. on tensile strength at fracture with 11.91 % on elongation. Nanocellulose Filament used in this research would be applicable for the future textile and material industry that possibly replace fossil fuel-based material.

Hydrogen is an alternative energy source that can replace fossil fuels. The latest breakthrough idea for producing hydrogen fuel is by utilizing biomass in bioelectrochemical systems, which is Microbial Electrolysis Cell (MEC). MEC is a method for producing hydrogen gas that is managed from organic materials, including from wastewater. In addition to very low energy consumption, the MEC system is able to use sludge waste as a substrate for the bacterial community to be implemented. The rate of hydrogen production with MEC is relatively lower when compared to air fermentation and electrolysis methods. Efforts that can be made to increase hydrogen production are by operating the MEC system at optimal distance between electrodes. One of the major problems that arises from the use of the MEC system is methanogens, the methane-producing bacteria. This methanogen consumes biohydrogen produced at the cathode which cause the loses of biohydrogen production in MEC system. In this research, biological control methods is utilized in bioelectrode by enriching it with denitrifier bacteria to inhibit the growth of methanogens. The MEC reactor is carried out in configuring a single-chamber MEC. Variation in denitrifier bacteria used and distance between electrodes aim to find the optimal conditions. The composition of the reactor chamber gas head is supported by using Gas Chromatography to analyze hydrogen and methane reserves. The addition of Pseudomonas stutzeri as biological control of methanogenesis could reduce the methane up to 76.28% compared to the control reactor at the first cycle. The presence of Pseudomonas stutzeri was also able to increase the H2 produced 128% higher compared to the control reactor. With the electrode spacing 0.5 cm, the H2 produced 65% was higher than the MEC reactor with 1 cm-electrode spacing. The 0.5 cm space was the optimum space for this experiment since it still supported the growth of the exoelectrogen bacteria and reduced the internal resistance within the MEC system.