PHASE ANALYSIS AND PHYSICAL PROPERTIES OF B2O3-ADDED ZIRCON CERAMICS SINTERED AT 1300 °C

This study was aimed to know the effect of B2O3(boria) addition on the phase composition and physical properties of zircon ceramics.The raw zircon powder used in the study was a purified natural zircon sand from Kereng Pangi, Central Kalimantan, Indonesia. The zircon ceramics were prepared by a solid state reaction method with variation of B2O3 addition of 3 wt%, 6 wt% and 9 wt% and sintered at 1300 °C for 5h. The phase composition, density and microstructure were characterized using X-ray diffraction (XRD), densimeter and Scanning Electron Microscope (SEM), respectively. Vickers Hardness measurement was perfomed at the polished surface of the ceramics. Results showed that all samples contained pure zircon phase, i.e. there was no effect of B2O3 addition on the phase composition. In general, the density and hardness increased with increasing B2O3 addition, but addition up to 9 wt% is not optimum to achieve ultra-dense zircon ceramics. Furthermore, the SEM image also showed no significant difference in average grain size. The crystallite size has grown nearly eight times (325 nm) of its original powder. The Vickers hardness of the ceramics is not significantly influenced by the addition of boria. It appears that the boria failure to increase densification also results in the extent of contact between grains which then produces relatively large zircon grains.

SMARTPHONE-BASED ANALYSIS OF CLOTH MASKS PORES SIZE

Until now, the world is still facing the spread of the SARS-CoV-2 virus that causes COVID-19. This virus can be transmitted from human to human through droplets, so more vigilance is needed to avoid contracting this virus. One of the steps to minimize the spread of Covid-19 is to wear a face mask. In practice, most people prefer to use cloth masks than disposable medical masks because they are cheap and reusable. Cloth pore size influences the filtering ability of the cloth masks. Therefore, it is necessary to analyze the efficiencies of the cloth masks. In this study, we developed a method for measuring the pores of a cloth mask using a smartphone. In this study, we developed a method for measuring the pores of a cloth mask using a smartphone. We used the camera zoom application on a smartphone and analyzed the image using image processing software, ImageJ. We appliedHuang's algorithm to adjust the image binarization threshold then calculated the Feret diameter as the pore size of the mask. According to the analysis, the pore size ranged from 0.133 to 0.232 mm, and the efficiency ranged from 77.4 to 82.6%.

CHARACTERIZATION OF CLAY MATERIALS USED FOR POTTERY PURPOSES FROM RENDENG, MALO, BOJONEGORO

Clay material from Rendeng, Malo, Bojonegoro was studied by mineralogy and physicochemical characterization to evaluate its potential suitability as a raw material in pottery application. X-ray Diffraction (XRD) and Fourier Transform-Infrared (FTIR) spectrometry were used to establish the mineralogy composition. Meanwhile the physical properties were identified by particle size distribution and consistency limits. Chemical composition was carried out by X-ray Fluorescence Spectrometer (XRF). The results of XRD characterization revealed that clay from Rendeng Village, Malo, Bojonegoro contained kaolin, quartz, and feldspar. Physical characterization shows that clay material is a less plastic type based on Atterberg method. Based on the chemical compositions indicated that SiO2, Al2O3, CaO, and Fe2O3 were abundance oxides. Therefore, clay from Desa Rendeng was only suitable for the pottery purposes because most of its mineral compositions did not meet the quality requirements for making advanced ceramics.

DESIGN OF KEMPLANG CRACKERS DRYER USING TRAY DRYER BY UTILIZING BIOMASS ENERGY

The drying process on kemplang crackers is one of the factors that determine the quality of the resulting product. Conventional drying has many disadvantages, namely fluctuating heat and poor hygiene that will affect product quality. So that kemplang crackers can be stored for a long time, it is necessary to reduce the water content of kemplang crackers. Drying kemplang crackers can use a drying rack with a biomass energy source from coconut shells. This study aims to design a tray dryer with biomass energy to obtain dryer performance based on the drying rate and to obtain a product that meets SNI No. 8272-2016. The treatments that were varied were set point temperatures of 55oC, 60oC, 65oC, and 70oC with mass variations of 50 gr, 100 gr, and 150 gr. The results showed that the optimum drying conditions at 70oC for 4 hours with an air velocity of 5.2 m/s2 obtained 9,84% moisture content in 50 gr kemplang crackers, 15.39% in 100 gr crackers and 19,2 in kemplang crackers 150 gr and a drying rate of 0,035028 kg/hour m2. The drying process requires 5,24 kg of dried coconut shell to produce heat energy of 95.358,81024 KJ with a by-product in the form of liquid smoke.

COMPARISON OF EFFICIENCY AND CARBON EMISSIONS OF FILAMENT ELECTRIC STOVES AND INDUCTION ELECTRIC STOVES

Issues related to energy sustainability and carbon emission reduction are continuously being concerned by the Government of the Republic of Indonesia. Various efforts and programs have been launched to achieve targets of the related issues. As known that energy use for cooking by the household is continuously increasing in relation to population growth that will of course increase in energy need which relates to the sustainability of presence energy and carbon emission. Accordingly, the LPG stove conversion program to an electric stove was introduced in order to achieve the target to solve such issues. This paper compared of efficiency and carbon emissions of both electric filament stoves and induction stoves. The result indicated that the induction stove has better efficiency compared with the electric stove. The study also was proved that the carbon emissions for both types of stoves were relatively low in comparison with LPG stoves. However, the enormous operational power of the induction stove is still a challenge that must be resolved to achieve the target of energy sustainability in Indonesia.

THE USE OF (Mg0.9Zn0.1)TiO3+2wt.% Bi2O3 CERAMICS AS A DIELECTRIC RESONATOR OSCILLATOR MATERIAL AND CHARACTERISATION OF STRUCTURE, MICROSTRUCTURE, AND DENSITY

Magnesium titanate (MgTiO3)-based ceramics have the potential for use in the telecommunications industry at microwave frequencies, including as a resonator in dielectric resonator oscillator (DRO) circuit. This research is intended to study the application of (Mg0.9Z0.1)TiO3+2wt.% Bi2O3 (abbreviated MZT01-2) ceramics as DRO material and characterize the structure, microstructure, and bulk density. Fabrication was carried out by ball milling between (Mg0.9Z0.1)TiO3 crystalline powder and 2wt.% Bi2O3 powder. The milled powder was compacted at certain pressure using a die press to become pellets. All pellets were sintered at 1000, 1100, 1200°C for 4 h to obtain ceramics. The structural characterization using XRD showed that the three ceramics contained the main MgTiO3 phase, each 93.63, 93.83, and 90.78% molar, the rest was the MgTi2O5 phase. The increase in sinter temperature causes the lattice parameter and the unit cell volume to decrease. The Archimedes bulk density was 2.928; 2.832 and 2.736 g/cm3. The microstructure is solid surfaces with a grain diameter of 1.9-2.3 μm accompanied by pores. As DRO materials, the three ceramics exhibited a resonant frequency at 5.11, 5.08, and 5.12 GHz which shows that the ceramics can be applied as DRO materials at microwave frequencies. The sinter temperature variation tends not to affect the resonant frequency position.

SOC (STATE of CHARGE) THREE-CELL LEAD DYNAMIC BATTERY MODEL

Three-cells dynamic lead-acid battery has been widely manufactured as the latest secondary battery technology. It is being carried out by 10 cycles of charge-discharge treatment with a various types of SoC, such as 100% (Full charge 5100 mAh), 50% (2550 mAh), 25% (1275 mAh) and discharge current of 0.8A. This experiment aims to analyze the treatment of SOC conditions on the performance of the lead-acid battery. The cyclicality test has performed using a Battery Management System (BMS) by applying an electric current at charging 1 A and discharging 0.8A. The results of the SOC charging conditions at 100%, 50%, 25% respectively gave a difference in the value of voltage efficiency of 84%, 87%, 88%, capacity efficiency values of 84%, 80%, 69%, energy efficiency values of 70%, 70%, 62%. The 100% and 50% SOC treatments showed better performance and battery energy the 25% SOC treatment. This research can be a recommendation to predict the performance of the lead-acid battery model during the charging and discharging process.

DESIGN AND BUILD OF AUTOMATIC WASTAFEL USING ULTRASOUND HC-SR04 SENSOR BASED ON ARDUINO

The lack of public concern for washing hands during the Covid-19 pandemic, the authors designed an automatic sink using an arduino-based HC-SR04 ultrasound sensor to attract the public's interest. By making automatic sink technology using the HC-SR04 ultrasound sensor based on Arduino for use in hand washing by the community. This study uses experimental research that examines the effect of automatic washbasin with people's behavior in washing hands. By testing the use of water in 20 seconds, 43 people can use it in one day, and soap can be used by 6 people in one day in 5 seconds. The automatic sink using the HC-SR04 ultrasound sensor based arduino can be used with a distance that is made less than 15cm designed to be practical and sterile because it is used that does not touch faucets or soap. The conclusion of the study is that if there is an object that approaches the ultrasound sensor within a distance of less than 15cm, the water pump will be active for 20 seconds or the soap pump for 5 seconds will automatically come out. And it will run out if used for 934 seconds in 1 liter gallon or 46 people a day and the use of soap for 5 seconds will run out approximately 6 people in one day.