Advances in Science and Technology Vol. 128

Abstract: Aim of this study is to investigate the effect of tempering with various heating temperatures (200, 300 and 450°C) and time (2, 4 and 6 hours) on toughness and microstructure of high carbon steel in order to improve its properties. The toughness was measured using the Charpy test and the changes of microstructures were evaluated by Optical Microscope. The analysis was performed for specimens before and after tempering. The results showed the energy of impact and the impact number (toughness) of high carbon steel JIS G4401 were increased by rising tempering temperature. Besides, by addition of the time of tempering, the energy of impact and the toughness were also enlarged. The microstructures of specimens after tempering consisted of ferrite and pearlite phases where the pearlite phase appeared more dominantly during increasing temperature and time of aging.

Abstract: The natural resources of the coastal sands of North Sulawesi are very potential and need to be explored and developed. Sand is composed of compounds based on the location of the sand along the coast. The potential of beach sand, namely Si (Silicon) can be a basic material such as SiC (Silicon Carbide) functional materials, semiconductors, and others. The first stage is sampling of white sand at several points and varying sand depths. Furthermore, the white sand is cleaned of impurities and iron sand. The second stage is sand preparation, sand identification and the third stage is silica extraction using the Alkali Fusion method using a high concentration base. Testing of elemental composition using XRF (X-ray Fluorescence), crystal structure using X-Ray Diffraction, and functional groups using Fourier Transform Infrared. The results of XRF analysis show that beach sand is composed of chemical compositions with a chemical component of CaO > 80%, the results of XRD analysis show that Silica (SiO2) compounds are in the form of quartz and show the Si-O functional group.

Abstract: Fabrication of Disperse Orange 3 thin film for photonics technology application has been carried out by using PVD method. The molecular structure of this film have been investigated by using FTIR and also by IRRAS methods. The optical properties have been investigated by UV-VIS measurement. In this paper the effect of molecular orientation and the molecular stcking/arrangement within the thin film were discussed.

Abstract: This study aims to produce and characterize CaO (calcium oxide) from limestone, a natural product of Lobong Village. Calcination is the thermal decomposition of limestone to remove carbon so that it can produce calcium oxide. One of the functions of CaO is as an eco-friendly catalyst that does not produce toxic or hazardous waste and can be reused. CaO resulting from the calcination process at a temperature of 900°C for 1.5 h was characterized using XRD, SEM, FTIR, and EDS. XRD analysis of calcined limestone produced 2θ (h k l) diffraction peaks, namely 32.228^o (1 1 1), 37.389^o (2 0 0), 53.864^o (2 2 0), 64.169^o (3 1 1), and 67.404^o (2 2 2) which indicates the dominance of CaO. SEM analysis shows that the morphological structure of Lobong limestone after calcination is more porous than before. Studies by FTIR show that the chemical bonds of carbonate groups in the calcined limestone are decreasing. EDS analysis also shows that the mapping of carbon, which forms carbonates in calcined limestone, is decreasing.

Abstract: This research aims to design a human body temperature detection system based on the Internet of Things (IoT) and featuring the output with human voice. The implementation of the IoT concept using the MQTT Protocol. The stages in developing this system are needs analysis, design, develop, testing and evaluation. Principally, this system works as follows, once the temperature sensor detects a human temperature, the microcontroller will process this temperature data (1) convert the data into human voice and (2) sending (publish) the data to a web server in the internet. In this research uses Adafruit.com as Mqtt broker. Anyone subscribes to the feeds of the Adafruit will receive such temperature data automatically. To determine the output of the human temperature we must adjust with +3 from the original result of MLX90614 in the normal room temperature. By this adjustment we have the best of error average 0.96% and an average difference of result 0.35°C. It means, by adjustment +3 from the original result of the sensor will conform with the standards of IEC No. 13B-23 and the 13th revision of Melexis in 2019, where the maximum of error tolerance is 5% and the temperature difference is 0.5°C. For distance testing, the result is that the farther the object from the MLX90614 sensor will result the greater errors value and the object closer to the sensor, will result the smaller error. The average delay time to send data to the Adafruit Webserver and android application is 1.53 seconds.

Abstract: Ignition energy is an important key factor needed in modern life concept with regard to a high technology usage. Almost 90% of the world's energy needed is obtained from fossil fuels, where diesel fuel is one of them. Coconut oil is one of bio-diesel resources which is very potential to be developed and it has a potency to replace diesel fuel. It is, therefore research regarding the effect of diesel fuel and coconut oil mixture on engine torque and rate of fuel consumption at various RPM variations is needed to be done. The tested engine was done on a 1200 cc Isuzu Panther using a mixing ratio of diesel fuel (S) and coconut oil (MK), namely: (1). 100% S: 0% MK (pure diesel), (2). 95% S: 5% MK, (3). 90% S: 10% MK, and (4). 85% S: 15% MK. The research method was a quantitative testing method on a laboratory scale. Research finding shows that the engine torque at the 95: 5 and 100: 0 mixtures has almost the same value of almost all of engine rotations. At the 90: 10 and 85: 15 mixing ratio, the engine torque tends to be unstable significant. It can be concluded that the ideal and stable engine torques were found at the combustion of 100: 0 and 95: 5 fuel mixtures. The lowest fuel consumption rate occurred at the combustion of 100: 0 and 95: 5; while the highest fuel consumption were occurring on a mixture of 90:10 and 85:15.

Abstract: Consumers in choosing clothing products are increasingly considering many things, including models that are up to date with a touch of new technology, good quality but at competitive prices on equivalent products. This condition needs to be observed by a fashion entrepreneur, especially with regard to the issue of how to produce clothing at competitive prices (relatively cheaper for equivalent quality) without compromising on quality and with innovative models. Waste from the fashion production process, especially patchwork, can be utilized so that it can become a new product (and at the same time present innovation) and can bring profits. In this way, the use of raw materials for the main product (clothing) is more efficient, and this will also have an effect on reducing production costs. This analytical presentation is emphasized on the problem of how to make the price of fashion products more competitive without abandoning quality requirements and with up to date models. In addition, it also presents an illustration of how to make fashion products using efficient raw materials, namely by utilizing waste clothing products for product innovation (upcycle). These products are in the form of accessories or complementary clothing and household accessories which are done using patchwork techniques.

Abstract: This study aims to analyze the water quality of Lake Perintis and Lake Limboto as irrigation water sources in Gorontalo Province. This study was carried out by considering the importance of water from these two lakes for irrigating the rice fields. 2 lakes became the locations for sampling in this study, namely Lake Limboto and Lake Perintis. Because this study was an initial survey, the researchers only applied one-site and one-time sampling for each lake. The observed parameters were temperature, TDS, COD, turbidity, phosphate, pH, nitrate, iron, manganese, cyanide, arsenic, fluoride, chlorine, manganese, magnesium, calcium, sodium, potassium, total coliform, and E. coli. The analysis was carried out at the Water Quality Laboratory, Health Office of Gorontalo and Integrated Research & Testing Laboratory of Gadjah Mada University. The sampling for total coliform was carried out aseptically, while measurements in the laboratory applied the MPN method. The way of taking chemical and physical samples followed SNI 8995-2021. Furthermore, the collected data were analyzed following Government Regulation No. 22/2021 Appendix VI regarding Lake Water Quality Standards. In analyzing water for irrigation purposes, the researchers applied the Sodium Adsorption Ratio (SAR) classification. Results showed that the water quality of Lake Perintis and Lake Limboto did not meet the requirements stipulated in Government Regulation No. 22/2021 because the chlorine, COD, and phosphate parameters were above the required quality standard. In addition, we also found that the pollution level in Lake Limboto was higher than that of Lake Perintis. Moreover, the results of the SAR analysis indicated a score of 7.975 for Lake Perintis (classified in the low sodium criteria) and a score of 11.23 for Lake Limboto (classified in the medium sodium criteria).

Abstract: This study aimed to determine the characteristics of activated charcoal from mangroves resulting from pyrolysis and activation with 3M KCl using Fourier Transform Infra-Red (FTIR), X-Ray Diffraction (XRD) and ash content analysis and to determine the ratio of Pb, Fe and Cd metal content in river water before and after filtered with activated charcoal. The results of the FTIR test for charcoal from mangroves resulting from pyrolysis and activation with KCl showed the presence of O-H, C=C, C-H, C-N and C-Cl groups as additional groups that appeared after the activation process. The results of XRD analysis show that the lattice parameter (α) can be calculated, namely in pyrolysis mangrove charcoal = 5.79 and charcoal from pyrolysis and activation mangrove wood = 5.88. The results show that there is a change in the distance between the crystal planes after activation, with the known value of, the results of d-spacing 3 strong peaks are 3.39 , 2.94 and 5.88 . The results of the analysis of the ash content are 15.4% and exceed the maximum percentage that has been determined, because there are still impurities attached to the carbon surface. The results of the analysis using Atomic Absorbtion Spectrophotometry (AAS) showed that there were differences in the levels of Pb, Fe and Cd in river water before and after being filtered with activated charcoal. There was a decrease in Pb levels from points 1,2 and 3 as much as 73%, 49% and 55.23%. Meanwhile, Fe metal decreased from points 1, 2 and 3 as much as 58%, 66% and 81%. And on Cd there was a decrease of 44%, 61% and 92%. From these percentage results, activated charcoal from mangroves can be said to be effective because it can absorb metals in river water. Pb metal in river water in East Kombos Manado City has passed the concentration specified in Government Regulation of the Republic of Indonesia No. 22 of 2021, Class II Water Quality Standards.