Chairul Hudaya
University of Indonesia, Electrical Engineering, Faculty Member
Analisis implementasi teknologi batubara bersih dalam rangka penurunan emisi gas rumah kaca pada PLTU program pembangunan 35.000 MW = Analysis on clean coal technology implementation for reduction of greenhouse gas emissions from coal fired power plants of electricity development program 35. 000 ...more
In this study, 238 power transformers (PTs) with operating voltages between 150500 kV and capacities in the range of 60–167 MVA are tested for partial discharge (PD). Thirty-eight of the PTs exceeded the pre-determined value of 70 pC at... more
In this study, 238 power transformers (PTs) with operating voltages between 150500 kV and capacities in the range of 60–167 MVA are tested for partial discharge (PD). Thirty-eight of the PTs exceeded the pre-determined value of 70 pC at 1.5 maximum voltage of the PT. Failure analysis of the failed 38 PTs showed that 21% of the PD sources originate from the winding cylinder, which is formed by bonding the edges of a pressboard with an adhesive. Therefore, in this study, the effect of casein- and polyvinyl-based adhesives used in winding cylinders was investigated through standard PD measurements. The results indicate that pressboards bonded with casein-based adhesives exhibit PD values 20–25 pC lower than those bonded with polyvinyl-based adhesives (50–400 pC) at identical applied voltages (7.5–25 kV or 3–10 kV/mm). The excellent performance of casein-based adhesives is mainly attributed to its porous structure, which accelerates the impregnation of oil into the adhesive and pressboard, as revealed by scanning electron microscopy observations. This practical study will be beneficial in the process of designing and manufacturing PTs and highlight materials for producing PTs with low PD values.
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In a furniture decorative laminate industry, boiler is an important component to produce steam for machinery operation. Thus, improving efficiency of boiler becomes crucial step to reduce the operational cost and to increase the... more
In a furniture decorative laminate industry, boiler is an important component to produce steam for machinery operation. Thus, improving efficiency of boiler becomes crucial step to reduce the operational cost and to increase the productivity. In this study, we investigated the replacement of steam trap in a boiler system using orificebased steam trap. Based on the real operational data, we found that the modified steam traps installed in an impregnation machine line could increase the boiler efficiency and decrease the fuel consumption by 7.1%, reduce the treated water by 5.5%, and decrease the condensate water volume by 1.9%. These phenomena occurred because there are no steam losses thus the boiler will work efficiently leading to the reduction in the use of fuel and treated water. The cost calculation concluded that the replacement of steam traps contributes to 2 months pay back period, Net Present Value (NPV) of USD 57,457, and Internal Rate of Return (IRR) of 562%.
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The electricity load growth should be planned appropriately to meet energy demand in a certain area. Electricity consumption growth is generally proportional with the economic and population growth. Using historical data on Gross Domestic... more
The electricity load growth should be planned appropriately to meet energy demand in a certain area. Electricity consumption growth is generally proportional with the economic and population growth. Using historical data on Gross Domestic Regional Product (GDRP) and population growth, the electricity load growth in the near future can be statistically predicted. The relationship between economic and population growth trend and total customers as well as the demands of contract electricity energy growth trend could be connected by the linear regression method to predict electricity energy consumptions. Through a Simple Econometric Simulation System (SIMPLE-E) program run in Microsoft Excel application, linear regression trend can be calculated. The purpose of study is to predict the growth of electricity consumption in Tangerang City-Indonesia, for the next ten consecutive years (2019-2028). Customer data that will be analyzed consist of five segments, which are Residential (R), Comm...
The energy crisis in the future will be a threat for human life. Many advancements of technology currently focus on creating something that perform better than its predecessor but consuming less power. Light-emitting diode (LED) lighting... more
The energy crisis in the future will be a threat for human life. Many advancements of technology currently focus on creating something that perform better than its predecessor but consuming less power. Light-emitting diode (LED) lighting technology has been introduced as a breakthrough of technology which possesses big advantages rather than other lighting technologies. LED lighting technology is able to produce a high luminous flux with very low power consumption, and also lasts longer than others. By consuming lower power, hence the amount of energy being consumed in order to generate the same amount of light will be reduced, and hence, energy saving will happen. This study discusses the replacement analysis of lighting at classrooms at Engineering Center of Faculty of Engineering Universitas Indonesia. The analysis is in terms of illuminance aspect, power quality performance and cost, and it is done by replacing the existing compact fluorescence lamps (CFL) with three different o...
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Transformer is one of the main components in distribution system of electrical power system towards the consumers, thereby any damage to the transformers will hinder the distribution of electricity towards the consumers, and in turn will... more
Transformer is one of the main components in distribution system of electrical power system towards the consumers, thereby any damage to the transformers will hinder the distribution of electricity towards the consumers, and in turn will make the SAIDI and SAIFI levels go up. High temperature in transformers can cause degradation in the insulation of transformers which in turn will cause failure in transformers. When the temperature in winding reaches or goes beyond the limit of $110^{\circ}\mathrm{C}$, a degradation in insulation will start happening and the remaining life of transformers will decrease. Damage in transformers will cause disturbance in electrical power system and result in a major economic loss. Before damages occur, transformers need to be changed up until it is deemed to be no longer efficient, this can be done by replacing the transformer that is about to be damaged. To predict when a transformer is about to break, a calculation is made based on thermal modelling...
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The grid-connected Photovoltaic (PV) System was installed in the rooftop of Energi Building, PUSPIPTEK in 2017 located in Serpong, South Tangerang. The System consists of 40 modules @265 Wp, a 10 kWh battery system, and a 10250 kW... more
The grid-connected Photovoltaic (PV) System was installed in the rooftop of Energi Building, PUSPIPTEK in 2017 located in Serpong, South Tangerang. The System consists of 40 modules @265 Wp, a 10 kWh battery system, and a 10250 kW grid-tie inverter. This study presents the performance analysis of the PV system based on the eight-months monitored data from July 2019 to February 2020. The evaluated parameters of the PV system include yields, performance ratio, capacity factor, energy efficiency, and average daily energy output of the PV system. The results show that the average value of the performance ratio and capacity factor during the eight-months monitored period were 82.42% and 14.07% with average values of the array (Ya), final (Yf ) and reference (Yr ) yields were 3.49 kWh/kWp/d, 3.38 kWh/kWp/d, and 4.12 kWh/kWp/d, respectively. Meanwhile, the average daily energy output of the PV system during the eight-months monitored period was 36.92 kWh per day with the average values of ...
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Battery Energy Storage System (BESS) can be utilized in various ways to improve the reliability, durability, and efficiency of grid operations. With the advancement of battery technology and rapid cost reduction, BESS has become very... more
Battery Energy Storage System (BESS) can be utilized in various ways to improve the reliability, durability, and efficiency of grid operations. With the advancement of battery technology and rapid cost reduction, BESS has become very promising. An accurate BESS model in simulation platform is very important to design an efficient BESS-connected powered system. Battery as one of the main components that govern BESS perfomance need to be modeled. There are many battery models that has been developed. In this paper, some of battery models will be studied and the comparison of different battery models is also presented.
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In a rural area, where electricity supply is limited, water accessibility for the society generally becomes a major concern. Here, we proposed the alternative solution which is an integrated solar-powered water pump system using the DC... more
In a rural area, where electricity supply is limited, water accessibility for the society generally becomes a major concern. Here, we proposed the alternative solution which is an integrated solar-powered water pump system using the DC concept. We investigated the optimum condition and the power conversion before and after the installation of photovoltaic (PV) panels. The correlation between the total water lift and flow rate has been determined as one the parameter designing the PV panel integration by assuming the total water lift as independent variables ($\mathrm{H}_{0}, \mathrm{H}_{1}, \mathrm{H}_{2}$, and H3 with 1-meter increment) and the electrical power as a dependent variable (the power supply only comes from battery). Using these schemes, we calculated the efficiency of these four different conditions were 2.73%, 12.21%, 18.44%, and 15.34%, respectively. Meanwhile, after PV panel integration in which the total head H1=1.33 meter as dependent variables and PV modules as in...
Transparent conducting oxide (TCO) glasses play important role in many recent modern technologies including its application for dye sensitized solar cell. One of the most commonly used is indium tin oxide (ITO), however its price is... more
Transparent conducting oxide (TCO) glasses play important role in many recent modern technologies including its application for dye sensitized solar cell. One of the most commonly used is indium tin oxide (ITO), however its price is rather expensive. Therefore, the main purpose of the current research is aimed at replacing ITO with fluorine-doped tin oxide (FTO) which is easier and more economic for fabrication. For this purpose, tin chloride dehydrate (SnCl2.2H2O) precursor doped with ammonium fluoride (NH4F) source by using sol-gel method and spray pyrolisis technique can be considered as a new breakthrough in the making of conductive glass. In this work, the ammonium floride was doped at a ratio of 2 wt persen to tin chloride precursor with variations of deposition time (10,20 and 30 minutes) and substrate temperature (250, 300 and 350 °C) upon spray pyrolysis technique. The results showed that the longer deposition time the thicker glass layer is, providing smaller resistivity. ...
To meet the increasing electricity demand in the island of Indonesia, especially in areas that are lack access of electricity, it would be beneficial for these these islands to produce electricity using local potential renewable energy... more
To meet the increasing electricity demand in the island of Indonesia, especially in areas that are lack access of electricity, it would be beneficial for these these islands to produce electricity using local potential renewable energy sources. In this study, Papua Province, the eastern region of Indonesia with 28 Districts, where 2,114 villages do not have electricity access was taken as the region of interest. We focused the study in Pelebaga District where 2,073 households were unelectrified. To generate electricity, we simulated the district to be supplied with local energy resources combining renewable energy sources (wind and solar power system) and conventional one (diesel power plant) by taking the reliability and optimal generation cost into account. Furthermore, the economic analysis of hybrid power generation were carried out to get electricity price and electricity subsidy that fit the system. We found that the lowest possible electricity price that fulfill capacity shor...
Purification water has several methods; one of them is the plasma generation. The circuit used to generate plasma is Zero Voltage Switching (ZVS), where its use uses the resonance circuit concept. The main category to generate plasma glow... more
Purification water has several methods; one of them is the plasma generation. The circuit used to generate plasma is Zero Voltage Switching (ZVS), where its use uses the resonance circuit concept. The main category to generate plasma glow discharge is the circuit should generate high voltage output with a current range from 10 A to 1 A. In this study, when ZVS connected to the flyback converter with an input voltage of 12 V, the output values of 11 kV and 11 μA were obtained. In comparison, if ZVS was not connected to the flyback converter, the circuit is less stable, and the output value is weak because the output values only reach 8.97 kV and 8.97 μA. For maximum output, the ZVS circuit should be connected to the converter circuit due to the flyback converter can repair and strengthen the voltage. The flyback converter circuit is affected by the diode and capacitance effects. The effect of using capacitors in a flyback converter circuit is when the capacitance is too low, the ripp...
The coal shortage in the stockpile of the coal-fired power plant will possibly stop the power plant operation, which leads to negative impact to the company’s operational performance as well as the interconnected electrical power system.... more
The coal shortage in the stockpile of the coal-fired power plant will possibly stop the power plant operation, which leads to negative impact to the company’s operational performance as well as the interconnected electrical power system. Coal inventory is usually stored in the stockpile with an excess amounts to maintain service level. But the excessive level of coal would make a financial burden in terms of storage and maintenance costs. The objective of this study is to plan the optimum coal safety stock level in XYZ coal-fired power plant so it could serve the system with the low cost of inventory without affecting the operation reliability. The results showed that continuous review policy was more suitable to calculate coal inventory than periodic review policy because it stored less coal and limited stockpile capacity in the power plant. This scenario could reduce the cost of coal inventory planning up to ~ 14%.
Co-combustion testing of Low-Rank Coal (LRC) and Medium-Rank Coal (MRC) was carried out in a Circulating Fluidized Bed (CFB) Boiler with a capacity of 16.5 MWe to determine the effects on the performance and characteristics of operational... more
Co-combustion testing of Low-Rank Coal (LRC) and Medium-Rank Coal (MRC) was carried out in a Circulating Fluidized Bed (CFB) Boiler with a capacity of 16.5 MWe to determine the effects on the performance and characteristics of operational boiler parameters. Coal was initially divided in two different bunkers based on its quality. The big bunker was filled with LRC and the smaller one was filled with MRC. To observe further impact on boiler performance, four different flow ratio percentages were set up through the coal feeder. We found that increasing the MRC ratio contributed to the rising furnace bed and inlet cyclone temperature. This also positively affected the boiler efficiency with the highest value of 86.77 % with full of MRC. However, the co-combustion caused drawbacks due to inhomogeneous temperature distribution within those furnaces. The average bed temperature ranged from 974 0C to 1,000 0C. The Net Plant Heat Rate (NPHR) increased slightly by 3.95 % of the original fuel...
Thermoelectric Generator (TEG) is an application of the thermoelectric module forgenerate electricity according to the seebeck effect which takes advantage of the temperature differenceoccurring on both sides of the module. This study... more
Thermoelectric Generator (TEG) is an application of the thermoelectric module forgenerate electricity according to the seebeck effect which takes advantage of the temperature differenceoccurring on both sides of the module. This study aims to design a toolportable power generator by exploiting the energy loss in motorcycle exhaustin order to produce a power of 10. The design that is built is in the form ofelectrical design with series configuration and series-parallel configuration ascomparison, using 8 pieces of thermoelectric modules of type SP1848-27145 and modulesDC / DC converter. The mechanical design consists of 4 layers with visualizationusing Autodesk Inventor software. The shape of the tool is adapted to the shapeexhaust so that it can be removed and reinstalled with dimensions of 164.3 ????????× 205 × 23.135 ???????? and can maintain the temperature difference (????????) of 60 ° ????. ResultThe selected design uses a series configuration because it has the same amount of ...
Manufacturing process of oil immersed Power Transformer (PT) has significant effect to the value of its partial discharge (PD). PD is one of the most important parameters of PT to ensures the reliability and quality of the PT's... more
Manufacturing process of oil immersed Power Transformer (PT) has significant effect to the value of its partial discharge (PD). PD is one of the most important parameters of PT to ensures the reliability and quality of the PT's operation PT. As PT is one of the most important parts in electrical power system, PD becomes one of the key performance indicators for PT. The quality of manufacturing process of both liquid and solid insulations will reflect to the PD value of PT. Both solid and liquid insulation will form the overall insulation of integration of PT. One of the important manufacturing processes is vacuum and oil impregnation process. These processes ensure the removal of the moisture from PT insulation and keep maintaining PT from moisture ingress. In this study, the experiment is conducted to investigate the relation between vacuum and impregnation process duration to partial discharge value of 167 MVA 500/150 kV on single phase power transformer. Twelve (12) samples a...
Harmonics are a phenomenon of voltage waveform deviationand currents that are transmitted and distributed from source to load in the formpure sinusoidal waves. This research aims to learn aboutthe influence of harmonics on distribution... more
Harmonics are a phenomenon of voltage waveform deviationand currents that are transmitted and distributed from source to load in the formpure sinusoidal waves. This research aims to learn aboutthe influence of harmonics on distribution transformers in office buildings as wellcompare the effect on weekdays and holidays. From the measurement results inSudirman Central Business District is known that transformers 1 and 3 existharmonics with a current THD percentage of 25.27% and 22.32% on weekdays.While on holidays there is transformer 1 which has a percentage of THD current17.24% which exceeds the IEEE 519-1992 allowable limit of 15%.The dominant harmonics are the 3rd, 5th, and 7th harmonics. With a percentage of THDcurrents that exceed the standard limits will result in performance and even degradationdamage to electrical equipment or components. The results of the study show that at the momentsmall load (holidays) THD the resulting current is not too large due to the loadless use th...
Conversion of fossil fuels as an energy source can be achieved by optimizing the use of renewable energy. One of the most used renewable energy is solar photovoltaics (PV). At present, solar power plant is an electrification support... more
Conversion of fossil fuels as an energy source can be achieved by optimizing the use of renewable energy. One of the most used renewable energy is solar photovoltaics (PV). At present, solar power plant is an electrification support system for certain buildings because the abundant availability of solar radiation. On this research, Power and energy observations are carried out to determine measure the load power trend, the amount of energy flow from PV to the load, as well as import or export power from or to utility grid by direct measurement on Mosque of Faculty of Engineering, Universitas Indonesia. According to the study, the highest power generated by solar power plant mostly occurs at 12:00 – 13:00 with the highest power generated by PV is 2,344 W and the exported power is 939 W, and 32.19% – 55.67% electricity energy savings consumption from utility grid.
Building sector is one of the biggest energy consumption along with residential, transportations and industrials. Building Integrated Photovoltaic (BIPV) can be an alternative to reduce energy consumption in the building and to secure the... more
Building sector is one of the biggest energy consumption along with residential, transportations and industrials. Building Integrated Photovoltaic (BIPV) can be an alternative to reduce energy consumption in the building and to secure the energy reserves. This study investigates the application of BIPV on the rooftop and facade of a high-rise building in Jakarta. Here, both technical and economic feasibility study are outlined. We employed the Sunny Web Design software and econometric spreadsheet program to calculate the energy generation and required specifications. BIPV rooftop produces greater energy yield compared to BIPV facade. This is because more radiation can be captured by BIPV rooftop on optimum azimuth and tilt angle. The BIPV reduce 5.97% of energy consumption. From the economic side, the total project cost and revenue of BIPV application is, respectively, 11.4 million USD and 1.2 million USD. This study can be broadened to develop BIPV in Indonesia.
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Soekarno-Hatta Airport Railink Project is one of the projects prioritized by the Government of Indonesia (GoI) in order to provide reliable mass transportation to and from Soekarno-Hatta International Airport. This research discusses... more
Soekarno-Hatta Airport Railink Project is one of the projects prioritized by the Government of Indonesia (GoI) in order to provide reliable mass transportation to and from Soekarno-Hatta International Airport. This research discusses electricity needs for the operation of Soekarno-Hatta Airport Railway and compared them to those of the existing substation. The availability of electric power became the most crucial aspect for the viability of the project and will depend on the capacity of substations that will sustain this train trip. It was assumed that Manggarai – Batu Ceper line will be integrated with other electric train service, which is Commuter Line, and this condition results in a clash as to their operation and electric power demand. Two separate services, two different companies, and two different types of train that use the same one line and substations are the focus of this research. This research examines the reliability of substations that already exist as well as the additional ones, if necessary. The findings of this research indicate that Karet and Manggarai substations require a slight additional capacity, but, overall, the existing substations remain reliable even though there will be an additional capacity in 2030 in order to maintain reliability in performing power supplies to two different services. It is calculated that the cost incurred if the capacity is added reaches USD 4.3 million. As for the cost of electricity, it is estimated that it ranges from USD 85,000 to USD 100,000/month for the first year with 89 trips per day.
The electrification ratio in Indonesia has not yet achieved 100%, meaning there are still many areas without electricity access. As a key driven country development, electricity has a significant impact to the growth of telecommunication... more
The electrification ratio in Indonesia has not yet achieved 100%, meaning there are still many areas without electricity access. As a key driven country development, electricity has a significant impact to the growth of telecommunication industries. In such situations, it is therefore difficult to guarantee the reliability of the telecommunication network, in particular, the electricity supply for the base transceiver station (BTS). To overcome this shortage, locally available renewable energy sources can be a solution as a power supply for a BTS. This study proposes the use of the integrated photovoltaic (PV) system as a power sources for BTS in the remote and isolated areas where the electricity from the grid is unavailable. The results show that the use of PV system is capable of supplying the electrical load requirement of BTS and is very feasible in financial analysis. The designed PV system output can produce 1.16 kW, while BTS load is 1.15 kW. We found that the integrated PV system is capable of handling BTS load. In economic perspective, the investment cost to deploy PV system is affordable due to the advantage of PV system, which is easy to maintain and operate.
This study aims to determine the effect of the implementation of the Integrated Hajj Computerized System (SISKOHAT) on the improvement of Hajj services at the Ministry of Religion Office of Sumbawa Regency. This research is quantitative... more
This study aims to determine the effect of the implementation of the Integrated Hajj Computerized System (SISKOHAT) on the improvement of Hajj services at the Ministry of Religion Office of Sumbawa Regency. This research is quantitative descriptive. The type of data used, namely primary data, was obtained from the results of distributing questionnaires to prospective pilgrims, the general public, and SISKOHAT officers/managers in Sumbawa Regency. The sample in this study were 101 respondents who were prospective pilgrims, 113 respondents who were the general public, and 11 respondents who were SISKOHAT officers/managers. The data analysis method used is simple linear regression analysis which includes data quality test, classical assumption test, and coefficient of determination test. The results showed that the application of SISKOHAT had a positive and significant effect on Hajj services. In addition, the implementation of SISKOHAT has an effect of 82.1% on increasing hajj service...
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Lithium-Ion Capacitor (LIC) has shown promising performance to meet the needs of high energy and power-density-energy storage system in the era of electric vehicles nowadays. The development of electrode materials and electrolytes in... more
Lithium-Ion Capacitor (LIC) has shown promising performance to meet the needs of high energy and power-density-energy storage system in the era of electric vehicles nowadays. The development of electrode materials and electrolytes in recent years has improvised LIC performance significantly. One of the active materials of LIC electrodes, activated carbon (AC), can be synthesized from various biomass, one of which is the water hyacinth. Its abundant availability and low utilization make the water hyacinth as a promising activated carbon source. To observe the most optimal physical properties of AC, this study also compares various activation temperatures. In this study, full cell LIC was fabricated using LTO based anode, and water hyacinth derived AC as the cathode. The LIC full cell was further characterized to see the material properties and electrochemical performance. Water hyacinth derived LIC can achieve a specific capacitance of 32.11 F/g, the specific energy of 17.83 Wh/kg, a...
Lithium-ion capacitors (LIC) is believed to be an ideal option in certain application as energy storage device due to its properties either possessing high energy density (four times higher than electrical double-layer capacitor) or... more
Lithium-ion capacitors (LIC) is believed to be an ideal option in certain application as energy storage device due to its properties either possessing high energy density (four times higher than electrical double-layer capacitor) or having as much power density as a supercapacitor. In this study, a biomass-based activated carbon (WHAC) was prepared by using the water hyacinth plant through the activation process utilizing a chemical activating agent, KOH. The water hyacinth was carbonized at 500 °C for a 1 h holding time with a ramping temperature of 10 °C/min. Then, the LICs electrode is constructed by two different types of electrode, WHAC as the main active material of cathode and lithium titanate oxide (LTO) for the anode. The biomass-derived activated carbon exhibits a high specific surface area of 791.8 m2/g and a high pore volume of 1.13 m3/g. The assembled LiCs shows a reasonable electrochemical performance with a maximum specific capacitance of 1.12 F/g with the highest spe...
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The research and development of biomass-based activated carbon (AC) has attracted much attention from researchers due to the abundant resource of biomass, including corncob waste. The urgency to find alternative and innovative... more
The research and development of biomass-based activated carbon (AC) has attracted much attention from researchers due to the abundant resource of biomass, including corncob waste. The urgency to find alternative and innovative applications for simple, inexpensive carbon material can be obtained by synthesizing the corncob waste which is abundant renewable resource and suitable for carbon properties. The use of chemical agent during activation process is of important to produce the desired AC, including high surface area and excellent electrical conductivity. Among the various chemical agents, KOH and ZnCl2 have been widely applied for synthesizing AC. This study aims to find out the characteristics of corncob-originated activated carbon (CAC) using these two chemical agents. Step by step of activating carbon from corncob will be determined briefly. Corncob was dried and chopped. Then it was carbonized. After that, the carbon result was soaked in each chemical agent solution, KOH and...
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Abstract Despite the advantage of chemical vapor deposition (CVD) for realization of large area epitaxial growth of graphene on transition metal catalysts, both etching and transfer process of CVD-grown graphene sheets still remain a big... more
Abstract Despite the advantage of chemical vapor deposition (CVD) for realization of large area epitaxial growth of graphene on transition metal catalysts, both etching and transfer process of CVD-grown graphene sheets still remain a big challenge. Here we demonstrate the formation of multilayer graphene (MLG) sheets tailored from C60 thin films on the top of Si/Ni substrate without etching and transfer steps based on Ni films. This self-assembled process separates the MLG sheets from the conductive Ni catalyst, embarking a possibility for direct characterizations of MLG sheets. The fine-tuned C60 films (30 nm) are transformed into approximately 17 MLG sheets, thus making it large-area MLG sheets for a variety of direct applications.
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SiOC@C is a lithium-ion battery (LIB) anode candidate that is expected to suppress the high volume expansion of Si by the presence of activated carbon as a buffer layer. Silicon oxycarbide (SiOC) was obtained from phenyl-rich silicone oil... more
SiOC@C is a lithium-ion battery (LIB) anode candidate that is expected to suppress the high volume expansion of Si by the presence of activated carbon as a buffer layer. Silicon oxycarbide (SiOC) was obtained from phenyl-rich silicone oil through pyrolysis at 900°C with flowing Ar gas. The variation of samples used were 4 and 10wt.% SiOC and a pure carbon sample was also prepared for comparison. SEM images show a porous microstructure with a few chunks of agglomerate present. According to Brunner-Emmet-Teller (BET) test, the largest surface area of 542.738 m2/g was obtained at 10wt.%SiOC. Based on the performance test result, the highest discharge capacity of 223.3 mAh/g was obtained at the mentioned prime condition.
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Homogeneously dispersed Sn nanoparticles approximately ⩽10 nm in a polymerized C (PC) matrix, employed as the anode of a Li-ion battery, are prepared using plasma-assisted thermal evaporation coupled by chemical vapor deposition. The... more
Homogeneously dispersed Sn nanoparticles approximately ⩽10 nm in a polymerized C (PC) matrix, employed as the anode of a Li-ion battery, are prepared using plasma-assisted thermal evaporation coupled by chemical vapor deposition. The self-relaxant superelastic characteristics of the PC possess the ability to absorb the stress-strain generated by the Sn nanoparticles and can thus alleviate the problem of their extreme volume changes. Meanwhile, well-dispersed dot-like Sn nanoparticles, which are surrounded by a thin SnO layer, have suitable interparticle spacing and multilayer structures for alleviating the aggregation of Sn nanoparticles during repeated cycles. The Ohmic characteristic and the built-in electric field formed in the interparticle junction play important roles in enhancing the diffusion and transport rate of Li ions. SPC-50, a Sn-PC anode consisting of 50 wt % Sn and 50 wt % PC, as confirmed by energy-dispersive X-ray spectroscopy analysis, exhibited the highest electr...
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Among semiconductors, zinc oxide (ZnO) has received great attention due to its wide band-gap and high electron mobility, resulting in various strategic applications. Controlling the physical properties of ZnO is therefore a critical issue... more
Among semiconductors, zinc oxide (ZnO) has received great attention due to its wide band-gap and high electron mobility, resulting in various strategic applications. Controlling the physical properties of ZnO is therefore a critical issue in the fabrication of related electronic and optical devices. In this study, ZnO nanorods layers were grown on an ITO glass substrate via chemical bath deposition at low temperature. Prior to the growing process, the layers were deposited using a spin-coating technique. The seeding solution was made by dissolving zinc nitrate tetrahydrate and hexamethylene tetraamine in cold water (0C) for an hour using a cooler bath. The as-synthesized ZnOs were further subjected to different post-hydrothermal treatment series at a temperature of 150C for three hours at atmospheric pressure and at 100°C for one hour under one bar of nitrogen gas (N2) pressure. The characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and UV-Vis spectroscopy. The SEM results showed that the ZnO nanorods were grown as a vertically aligned hexagonal structure, while the XRD patterns showed a high intensity at the (002) plane. On the basis of investigation, it was found that under post-hydrothermal treatment at 150C for three hours with atmospheric pressure, the synthesis procedure resulted in nanostructures in the form of ZnO rods. Meanwhile, post-hydrothermal treatment at 100°C for one hour under one bar of nitrogen gas (N2) produced ZnO rods and tubes. In general, the posthydrothermal process provided a high degree of crystallinity. The optimum ZnO layer was obtained after post-hydrothermal treatment at 150C for three hours at atmospheric pressure, with a crystallite size and band-gap energy of ~18 nm and 3.20 eV, respectively.
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Lithium-ion capacitors (LICs) and lithium-ion batteries (LIBs) are important energy storage devices. As a material with good mechanical, thermal, and chemical properties, low-carbon silicon oxycarbide (LC-SiOC), a kind of silicone... more
Lithium-ion capacitors (LICs) and lithium-ion batteries (LIBs) are important energy storage devices. As a material with good mechanical, thermal, and chemical properties, low-carbon silicon oxycarbide (LC-SiOC), a kind of silicone oil-derived SiOC, is of interest as an anode material, and we have examined the electrochemical behavior of LC-SiOC in LIB and LIC devices. We found that the lithium storage mechanism in LC-SiOC, prepared by pyrolysis of phenyl-rich silicon oil, depends on an oxygen-driven rather than a carbon-driven mechanism within our experimental scope. An investigation of the electrochemical performance of LC-SiOC in half- and full-cell LIBs revealed that LC-SiOC might not be suitable for full-cell LIBs because it has a lower capacity (238 mAh g-1) than that of graphite (290 mAh g-1) in a cutoff voltage range of 0-1 V versus Li/Li+, as well as a substantial irreversible capacity. Surprisingly, LC-SiOC acts as a pseudocapacitive material when it is tested in a half-cell configuration within a narrow cutoff voltage range of 0-1 V versus Li/Li+. Further investigation of a "hybrid" supercapacitor, also known as an LIC, in which LC-SiOC is coupled with an activated carbon electrode, demonstrated that a power density of 156 000 W kg-1 could be achieved while maintaining an energy density of 25 Wh kg-1. In addition, the resulting capacitor had an excellent cycle life, holding ∼90% of its energy density even after 75 000 cycles. Thus, LC-SiOC is a promising active material for LICs in applications such as heavy-duty electric vehicles.
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Polymer electrolyte membrane fuel cells (PEMFCs) use the bipolar plate of various materials between electrolyte and contact electrode for the stable hydrogen ion exchange activation. The bipolar plate of various materials has... more
Polymer electrolyte membrane fuel cells (PEMFCs) use the bipolar plate of various materials between electrolyte and contact electrode for the stable hydrogen ion exchange activation. The bipolar plate of various materials has representatively graphite and stainless steel. Specially, stainless steels have advantage for low cost and high product rate. In this study, SUS 316 was effectively coated with 600 nm thick F-doped tin oxide (SnOx:F) by electron cyclotron resonance-metal organic chemical vapor deposition and investigated in simulated fuel cell bipolar plates. The results showed that an F-doped tin oxide (SnOx:F) coating enhanced the corrosion resistance of the alloys in fuel cell bipolar plates, though the substrate steel has a significant influence on the behavior of the coating. Coating SUS 316 for fuel cell bipolar plates steel further improved the already excellent corrosion resistance of this material. After coating, the increased ICR values of the coated steels compared t...