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High dependence on fossil energy sources is still a major problem in the national energy supply. To overcome these problems, the government encourages the utilization of renewable energy sources, one of which is biomass energy. Arthrospira platensis is one of the potential biomass as a future renewable energy source. This study aims to understand the thermal behavior and determine the kinetic parameter of the Arthrospira platensis activated carbon mixture with mass ratios of 10:3 during the combustion process. Thermal behavior analysis was carried out with the thermogravimetric analysis (TGA) instrument under the heating rates of 10 ℃/min using an oxygen flow rate of 100 ml/min with a temperature range of 25−1000 ℃. The results of the TGA showed that the mixed samples underwent three decomposition processes: moisture removal, volatile matter release, and solid residue decomposition. The Coats-Redfern fitting method was applied to calculate the activation energy in 2nd stage of decomposition by using ten reaction models. The result indicated that the order reaction model of F1 and the diffusion model of D1 were the most proper models for Phase I and II, respectively. [ABSTRACT FROM AUTHOR]

The biomass briquet in this research was intended to provide a fuel alternative with better combustion characteristics to reduce household air pollution (HAP) in remote communities. This article presented the effect of mixture ratio and densification pressure on the water resistance characteristics of a bio-briquette composed of carbonized rice husk (CRH) bound by Eichhornia crassipes (EC). The CRH and EC mass ratios are 80/20 (CRH80/EC20) and 20/80 (CRH20/EC80). The bio-briquettes were fabricated using a hydraulic press machine at 25 and 50 MPa pressure. The water resistance analysis was performed according to the ASTM D779-03 standard. The result shows that the highest water resistance was observed at 80CRH/20EC at a densification pressure of 50 MPa. [ABSTRACT FROM AUTHOR]

Power generation utilizing biomass thermal conversion has become one of the clean energy solutions. Arthrospira platensis (AP) microalgae belongs to 3rd-gen biomass. AP has high protein and relatively low ash content compared to other microalgae. On the other hand, AC has a high energy density and also provides a catalytic effect due to its high surface area. Inorganic material is one of the main factors in determining the potential of thermal conversion feedstock. Reactor fouling is caused by inorganic deposits, resulting in a decrease in heat transfer efficiency. Inorganic elements (Na, K, Ca, and Mg) also interact with biomasses' volatile matter, reducing thermal conversion to final product quality, such as pyrolysis oil. This study aimed to analyze inorganic elements change and its possible interaction with the thermal conversion product of AP and AC mixture at a mass ratio of 10:1 (10AP:1AC) compared to parent material using X-ray fluorescence (XRF) spectroscopy. The result indicated that AP contained chlorine and potassium as major inorganic elements of 54.8 and 19.6 (wt.%), respectively. AC inorganic elements are dominated by calcium and iron at 33.6 and 19.8 (wt.%) in that order. Blending AP and AC does not drastically increase total inorganic elements with maximum change in iron with 0.92%, which is the desired output where there is feedstock quality improvement without significant inorganic element increase. [ABSTRACT FROM AUTHOR]

Coconut, as an evergreen plant, grows abundantly and generates coconut shell waste (CSW) as a by-product, often mistreated when it can be used as a renewable energy source. This research aims to study the kinetics of CSW combustion through thermogravimetric analysis (TGA). The sample was combusted from a temperature of around 27℃ to 1000 ° C at a constant heating rate of 30 ° C min-1 and an airflow rate of 100 ml min−1. The thermogravimetric (TG) and derivative thermogravimetric (DTG) curves show that the thermal decomposition of the CSW existed in three phases: from room temperature to 135 ° C occurred the release of moisture content, followed by a phase of active combustion in which cellulose and hemicellulose were decomposed and burned, and finally after the temperature of 550℃ was the solid residue decomposition occurred. The combustion kinetic parameters of CSW were evaluated using Horowitz-Metzger's integral method. The moisture content release phase possessed a lower activation energy value (80.99 kJ mol−1) compared to the main phase of the biomass combustion of CSW (127.80 kJ mol−1). Thermodynamic parameters were investigated as well, and it was revealed that a certain amount of heat was needed to decompose the CSW sample into an activated complex throughout the combustion reaction. [ABSTRACT FROM AUTHOR]

TiO2 has a variety of uses, including gas sensors, catalytic performance, and as a reasonably priced and environmentally friendly photocatalyst. By synthesizing titanium dioxide nanoparticles with samarium and different sintering times, this work seeks to boost the effectiveness of these particles. A solvothermal technique was used to create nanoparticles of TiO2 that were doped with samarium. X-ray diffraction, fourier transform infrared (FTIR), vibrating sample magnetometer, scanning electron microscopy (SEM), and (VSM). First, 10 ml of ethanol and 0.1 ml of distilled water were used to dissolve 58 mol of samarium (III) acetate hydrate. The mixture then received 1 ml of titanium diokside that had been dissolved in 10 ml of ethanol. For three hours at room temperature, the solution was agitated with a magnetic stirrer. After stirring, the solution was transferred to a 20 ml stainless steel autoclave that had been lined with teflon and heated to 120 °C for 5 hours. The solution was also three times cleaned with ethanol after being allowed to cool at room temperature. The resulting white precipitate was gathered and allowed to dry for 12 hours at 60 °C. The dry sample underwent sintered for 1 or 2 hours at 500 °C. The XRD results demonstrated that the addition of sintering time decreased the crystallinity of Ti(Sm)O2. The SEM analysis revealed that the Ti(Sm)O2 sample had nice spherically shaped particles. The FTIR results revealed that the Ti-O bending mode of vibration has characteristics of 844 cm-1 and 815 cm-1 at various sintering times of 1 and 2 h. The sample's paramagnetic characteristics were shown by the VSM result. [ABSTRACT FROM AUTHOR]

Advances in nanotechnology today vary widely when viewed from the background of its application, the volume of nanoparticles has become the focus of researchers in the last decade. Hybrid nanoparticles are advances in the world of nanotechnology in which nanoscales of different sizes are added to each other using either the one-step method or the two-step method. This study intends to examine the hybrid titanium oxide-aluminium oxide (TiO2−Al2O3) nanoparticles by looking at the ratio of the volume to mass of different nanoparticles with different proportions of TiO2 (80%) and Al2O3 (20%) nanoparticles added with basic liquid with a fixed volume concentration of 0.1%. Ultrasonic testing and magnetic stirring ensure the stability of nanofluids as well as a way to synthesize nanofluids. Characterization of hybrid nanoparticles using x-ray diffraction (XRD), fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis to determine the phase of the crystalline material and see the morphology of the microstructure. The incorporation of TiO2+Al2O3 nanoparticles when viewed from the thermal conductivity and viscosity testing efficiently shows that the thermal conductivity has increased compared to the decreased viscosity, therefore hybrid nanofluids have a potential influence on the heat transfer system for increasing thermal conductivity and low viscosity. [ABSTRACT FROM AUTHOR]

This study is about the comparison between the effect of mixing of surfactant sodium dodecyl sulfate (SDS) and without surfactant on the oxide, which consists of Al2O3, TiO2, and CuO. Obtained by synthesis using a mass fraction of 0.1% SDS and 1 gram of Al2O3/TiO2/CuO dissolved in 1000 ml of distilled water and then stirred using a magnetic stirrer for 1 hour at a speed of 650 rpm. Furthermore, without surfactant, using 1 gram of Al2O3/TiO2/CuO was dissolved in 1000 ml of distilled water and then stirred using a magnetic stirrer. Then the ultrasonic process was for 1 hour to get more homogeneous nanoparticles. The addition of surfactants to nanofluids can increase the stability and viscosity of the nanofluids. Obtained from the results of the Viscometer test with temperature variations from 20 °C-60 °C, the values of viscosity, shear rate, and shear stress. Then tested on Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), and the results of the analysis of Conductivity Thermal and Specific Heat tests. This study aims to determine whether the addition of surfactant to oxide affects the value of viscosity, shear rate, shear stress, and thermal conductivity. [ABSTRACT FROM AUTHOR]

Research on nanofluids has developed rapidly in the application of its heat mechanism to a machine's performance. Heat mechanisms in nanofluids have emerged as promising fluid heat transfers, as for example in applications as a coolant in Thermal Photovoltaic. This study will discuss the effect of the Hybrid Copper Oxide/Titanium Dioxide (CuO/TiO2) Nanofluida on the rheological properties using based water. The purpose of this study was to determine the rheological properties and dynamic viscosity of the hybrid Copper Oxide/Titanium Dioxide (CuO/TiO2) nanofluids based-water performance on system. Hybrid nanoparticles were used to synthesize nanofluids using a volume ratio of 50:50 at 1L of water. Begin by mixing both of nanoparticles CuO and TiO2 with based-water using a magnetic stirrer at a speed of 650 rpm for 60 minutes, then followed by an ultrasonic stirrer for 1 hour so that the two nanoparticles become more homogeneous. The dynamic viscosity obtained using the NDJ-8S Viscometer uses variations in temperature of 20 °C, 30 °C, 40 °C, 50 °C, 60 °C with speeds of 6 rpm, 12 rpm, 18 rpm, 24 rpm, and 30 rpm. The results obtained in the form of viscosity, shear rate, and shear stress. [ABSTRACT FROM AUTHOR]

SWCNTSs nanofluids have high mechanical strength, good electrical conductivity, and high tensile strength. This research focuses on analyzing the thermophysical properties, heat transfer characteristics, and pressure drop of Single-Wall Carbon Nano Tube (SWCNT). Volume fractions used in nanofluids are 0.1%, 0.3%, and 0.5% and PVP surfactant 0.02% with distilled water as a base fluid (Aquades). SWCNTs nanoparticle characterization process was carried out by means of thermal conductivity test, and specific heat, viscosity test, density test, mettler toledo, FTIR (Fourier Transform Infra Red) test, XRD (X-Ray Diffraction) test, and SEM (Scanning Electron Microscope) test. The results obtained in this study include thermophysical properties, namely for the highest thermal conductivity of 0.690 W/m.oK, density of 1736.95 kg/m3, viscosity of 0.00166 kg/m3, and for specific heat of 3097.08 J/kg.oC, then for the heat transfer characteristics, the result is that it has an increase in the value of the heat transfer coefficient of 4.17 W/m2.°C, and the pressure drop value gets a value of 1.1968 N/m2. [ABSTRACT FROM AUTHOR]

These magnetic material samarium ferrite metal oxide nanoparticles have great potential to be applied in various industrial fields, especially electronic equipment because they have chemical-physical properties superior to the same material in large sizes, such as mechanical, electrical, magnetic, and optical strength. This study describes the synthesis and characterization of samarium ferrite and KOH additions obtained by hydrothermal method using 0.04 g Sm(NO3)3, 0.04 g Fe(NO3)3, and 9 g KOH dissolved in 100 mL deionized water with a magnetic stirrer for 30 minutes. After the synthesis process, it was transferred into a stainless-steel autoclave and kept at 120 °C for 5 hours, then the next step was cooling to room temperature, then washing with 10 mL ethanol in 3 stages, then drying at 60 °C for 12 hours, then continued with the calcination process in a furnace at 500 °C with a variation of time of 1 hour and 2 hours. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transmitter infrared (FTIR), then the samples were vibrated using a magnetometer (VSM). The SEM results showed that samarium ferrite nanoparticles consisted of agglomerates of soft nanoparticles, and XRD testing indicated an amorphous structure. The FTIR characterization results present the difference in functional groups between the sample with 1 hour sintering time and the sample sintering 2 hours. The VSM results successfully demonstrated the magnetic properties of samarium ferrite with different components and particle morphologies. [ABSTRACT FROM AUTHOR]

This research studied the effect of CTAB and PVP surfactants on the rheological properties of DWCNTs and MWCNTs nanomaterials in water-based nanofluids. Surfactants are used to bind between nanoparticles and fluid molecules, because some nanoparticles experience sedimentation on the nanofluid, so the addition of the surfactant is necessary. Mixing is carried out using a magnetic stirrer for 1 hour at a speed of 650 rpm, followed by sonication for 1 hour. This mixing uses a mass fraction ratio of 0.1% nanomaterial and 1:1 surfactant with nanomaterial. Nanofluids were tested by Scan Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Fourier Transform Infra-Red (FTIR). The NDJ-8S viscometer is a tool for finding the viscosity value of nanofluids with temperature variations of 20 °C, 30 °C, 40 °C, 50 °C and 60 °C using speeds of 6, 12, 18, 24 and 30 rpm. The results of the research included the effect of surfactant and temperature in the nanofluid on the viscosity and shear stress of the DWCNTs and MWCNTs nanofluids. [ABSTRACT FROM AUTHOR]

The experimental process carried out in this paper is to determine the convection heat transfer coefficient, overall heat transfer coefficient, and nanofluid heat transfer rate based on DWCNT (double-wall carbon nanotube) nanotubes applied to a shell and tube heat exchanger. The advantage of using DWCNT nanoparticles is the high thermal conductivity value. The volume fractions of nanoparticles were 0.1%, 0.3%, and 0.5% with the addition of PVP surfactant. Experimental tests were conducted to determine the heat transfer performance applied to a shell and tube type heat exchanger with upright baffles. This study aims to improve the heat transfer performance by utilizing nanofluids based on DWCNTs nanoparticles. As a result, using DWCNT nanofluids instead of base fluids increases the convective heat transfer coefficient values and overall heat transfer. The increase in the volume fraction of DWCNTs nanoparticles is also accompanied by an increase in the heat generated. The highest thermal conductivity was obtained by adding 0.5% volume of DWCNTs nanoparticles, which was 0.640 W/m.K. The highest heat transfer rate was produced by adding 0.5% volume fraction and 0.02% PVP with a result value of 70.191 W. [ABSTRACT FROM AUTHOR]

The most used instrument for solar energy harvesting is flat plate solar collector (FPSC). To improve the performance FPSC to get the optimal energy multi-walled carbon nanotubes (MWCNT) used on flat plate solar collector. This study describes the effect of synthesis of MWCNT-water based with concentrate ratio variations 0,1%, 0,3%, 0,5% and light intensity variations 415 W/m2, 515 W/m2 and 615 W/m2 with radiation from the sun simulator of 750 W/m2. Every light intensity was tested with different MWCNT-water nanofluids with concentrate variations 0,1%, 0,3%, 0,5%. The test was carried out 52 times for the collection of experimental data to provide valid test result. This study provides significant results on the use of nanofluids as a substitute for 0.5% multi-wall carbon nanotubes-water as a heat transfer fluid in improving the thermophysical properties that are superior to the base fluid. Increased light intensity and volume of nanoparticles also provide significant results on the performance of FPSC. In this paper, the greatest efficiency was found in the use of nanofluids and radiation intensity of 615 W/m2 with a volume of 0.5% nanoparticles with an efficiency of 90.45%. Increasing the fraction of nanoparticles into nanofluids provides the greatest efficiency-enhancing effect on the performance of FPSC. [ABSTRACT FROM AUTHOR]

In this journal, we present about the thermophysical and rheological properties of MWCNT (Multi-Walled Carbon Nanotubes) in Water-Based Nanofluid with various surfactants added. Cetyl Trimethyl Ammonium Bromide (CTAB), Sodium Dodecyl Sulfate (SDS), and Poly Vinyl Pyrrolidone (PVP) are used as a surfactant to be mixed nanofluids. The synthesis was carried out using magnetic stirring and sonicated at 650 rpm for 1 hour with a mass fraction ratio of 0.1%. Then tested on KD 2 Pro Thermal, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and X-Ray Diffraction (XRD). Viscosity was searched using NDJ-8S Viscometer with temperature variations of 20 ℃, 30 ℃, 40 ℃, 50 ℃, and 60 ℃ with rotations of 6, 12, 18, 24, and 30 rpm. So that the results obtained the value of thermal conductivity, specific heat, analysis of the surface's topography and composition, phase identification of a crystalline material, functional group, viscosity, shear rate, and shear stress. The result of our research is to be able to choose the best surfactant for MWCNT nanofluids as needed. It is hoped that the selection of appropriate surfactants for nanofluids can be further studied to improve the stability and dispersion of nanofluids for industrial production and long-term use. [ABSTRACT FROM AUTHOR]

The current use of energy has begun to lead to the use of renewable energy from nature, one of which is wind energy. A gust of wind can be extracted into new energy using the help of wind power plants. VAWT (Vertical Axis Wind Turbine) is a type of wind turbine whose main axis is arranged transversely to the direction of the wind and its main components are located at the base of the turbine. This study aims to determine the magnitude of the effect of variations in wind velocity and the number of blade levels of Hybrid turbines on turbine performance and aims to determine which variation is the most effective in extracting wind energy. This study uses a quasi-experimental method on the object of research in the form of vertical axis wind turbines of the Darrieus, Savonius and Hybrid types with variations in wind velocity of 3, 5 and 7 m/s and variations in the number of levels of one and two levels of Hybrid blades. The research data was obtained through simulation with the help of ANSYS 17.0 software using the CFD method (Computational fluid dynamics). The output of this research is the value of power, torque, tangential speed and efficiency generated by the wind turbine. The results showed that the wind velocity and the number of blade levels greatly affect the performance of the wind turbine. In this study, it was found that from the results of simulation testing using the CFD method, the best efficiency value was found in the one-stage Hybrid Darrieus-Savonius turbine at a wind velocity variation of 7 m/s of 3,31256% and Hybrid Darrieus-Savonius. Savonius two levels at 5 m/s wind velocity variation of 4,53786%. [ABSTRACT FROM AUTHOR]

Lubrication is one of the crucial elements affecting the engine performance of motor vehicles. It carries numerous functions, such as lowering friction, heat disposal, critical areas sealing, and other essential functions. Lubricant with thermophysical properties is reported to present better performance than conventional lubricant and is mostly used to produce superior lubricant performance. Nanolubricant represents the addition of nanomaterial into the lubricant to enhance its lubrication or thermophysical features. The nanoparticle suspension shows the agglomeration tendency induced by high surface activities. Accordingly, we used Oleic Acid to disperse the nanoparticle, forming a more stable suspension. The nanolubricant was synthesized using SAE 5W-30 lubricant, added with 0.5% of Al2O3, TiO2, and hybrid Al2O3/TiO2 nanoparticle, along with 10% of Oleic Acid. The research procedure was begun with the characterization of Al2O3 and TiO2 using SEM-EDX, XRD, and FTIR. The nanolubricant synthesis was carried out through four hours stirring process at 1000 rpm speed. Further, the thermophysical feature analysis covering the density, dynamic viscosity, and thermal conductivity was completed to identify the effects of nanoparticle addition on SAE 5W-30 lubricant. Meanwhile, the analysis of nanolubricant effects on the Honda Beat motorcycle performance covering the torque and power was completed using a dynamometer test. The results of data analysis showed an increasing nanolubricant's thermophysical properties to 751.7 kg/m3, at 0.06863 Pa.s density and 0.145 W/m.Ka dynamic viscosity in the thermal conductivity value. Meanwhile, the motor vehicle performance test showed an increasing torque of 8.24 N.m and 11.05 HP power. The nanolubricant added with TiO2/Al2O3, and oleic acid surfactant was observed to generate the highest performance of the motorcycle. [ABSTRACT FROM AUTHOR]

Mn0.8Zn0.2Fe2O4 nanoparticles have excellent applications in electronics and computer technologies related to their electronic and magnetic performances. This paper explores various synthesis routes of Mn0.8Zn0.2Fe2O4 nanoparticles using sol-gel, self combustion, and ball milling methods and followed by different treatment sintering at 700, 800, 900 °C. The functional groups of the Mn0.8Zn0.2Fe2O4 nanoparticles was conducted by means of Raman spectroscopy. The raman shift peak positions shown that the sample produced by ball milling process and sintered at 700 oC presented the highest intensity. The 700BM samples consists of three oxides samples which are zinc oxide, iron oxide, and manganese oxide synthesized by self combustion method. It make the concentration of molecules has better properties compared to the other method with the same temperature sintering. The VSM analysis with maximum magnetic field of 20,000 kOe on sol-gel method with different annealing temperature reported the magnetic saturation ranging from 1.3 to 5.9 emu/g. The hysteresis loop magnetic analyses of Mn0.8Zn0.2Fe2O4 by different synthesis method with maximum magnetic field of 15,000 kOe. Sample with ball milling has the highest value of magnetic saturation and coersivity that is 5.909 emu/g, 71.682 emu/g. [ABSTRACT FROM AUTHOR]

Massive utilization of firewood faced problems related to deforestation and harmful emissions. Indonesia experiences the fastest deforestation rate in the world (1000 km2/year). Household air pollution (HAP) resulting from the smoke of burning firewood causes premature deaths of around 165,000 to 68,000 each year in Indonesia. Liquified petroleum gas (LPG) and electricity are projected to be clean energy sources for households; however, switching to LPG fuel or electricity for remote rural households is constrained by their limited financial ability. Therefore, shifting the energy supply of rural communities from wood to fuel from agricultural waste can reduce the risk of deforestation, while reducing HAP is done by forming it into bio-briquettes. Manufacturing rice husk (RH) or carbonized rice husk (CRH) for bio-briquette fuels is intended to solve the problem of massive woody biomass and improve the combustion process to reduce the risk of HAP. This paper specifically investigates and compares the physical and chemical properties of RH and CRH as a first step to verifying their potential as bio-briquette materials. [ABSTRACT FROM AUTHOR]

Porosity is the fundamental property of solid fuel materials, considering that it will affect the diffusion of substances and heat and mass transfer during the thermal conversion process. This work examined the porosity of bio briquettes manufactured from a carbonized rice husk-water hyacinth mixture in a mass ratio of 50:50. Manufacturing was carried out under a hydraulic pressing machine with different pressures of 25 and 50 MPa. The results indicated that the sample of 25 MPa has a porosity of 70.02%, which is more porous than the sample of 50 MPa, which has a porosity of 53.93%. [ABSTRACT FROM AUTHOR]

The efficiency and effectiveness of motor vehicle engine performance in the automotive industry is strongly influenced by the condition of the lubricating oil used. Nanotechnology applied in lubrication has become a topic of research in the field of metal machining and manufacturing. Nanolubricant is useful for increasing the efficiency of lubrication because it has a rolling effect so that it can reduce friction that occurs. This research used SAE 5W-30 lubricant and added 0.5% Al2O3 and TiO2 nanomaterials. The initial step is to test the material characterization using SEM-EDX, XRD, and FTIR. Calculations and testing of thermophysical properties (density, viscosity, and thermal conductivity) were carried out to determine the effect of adding nanomaterials to the thermophysical properties of nanolubricant. Motorcycle performance testing uses a dyno test to determine the effect of nanolubricant on engine torque and power. The results of this study showed an increase in the thermophysical properties of the hybrid nanolubricant at a density of up to 806 kg/m3, an increase in the viscosity value of 0.06816 Pa.s, and a decrease in the thermal conductivity up to 0.101 W/m.K. The addition of nanoparticles to the hybrid nanolubricant also provides an increase in torque of 8.24 Nm and an increase in power up to 11Hp. [ABSTRACT FROM AUTHOR]