List of Accepted manuscripts:

Title: Synthesis of Au50Ag50 Alloy Nanoparticles From Metal Ions and Colloidal Nanoparticles Through Photochemical Reduction Methods Using Femtosecond Laser

Authors: Affi Nur Hidayah* and Yuliati Herbani

Abstract: Nanoparticles synthesized through photochemical reduction using femtosecond involve reducing agent that reduces metal ions into nanoparticles. We synthesized Au50Ag50 from metal ions and colloidal nanoparticles in four different conditions: (i) gold metal ions and silver metal ion, (ii) colloidal gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), (iii) gold metal ions and colloidal silver nanoparticles (AgNPs), and (iv) colloidal gold nanoparticles (AuNPs) and silver metal ions. Gold and metal ions were obtained from dilution of gold and silver metal salts. While gold and silver nanoparticles were obtained from gold and metal ions added into a quartz cuvette and irradiated by femtosecond laser in 10 minutes irradiation time. In the synthesis, every condition respectively mixed in 3 ml solution into a 10x10x45 mm quartz cuvette and irradiated by femtosecond laser in 5-, 10- and 15- minutes irradiation time. The result showed that Au50Ag50 alloy nanoparticles were successfully synthesized in four different conditions, and the LSPR (Localized Surface Plasmon Resonance) in 15 minutes irradiation time was observed at 454.51, 458.74, 459.60, and 457.29 nm in the condition (i), (ii), (iii), and (iv), respectively.


Title: Magnetic Susceptibility of Volcanic Soil on the Surface of Mount Singgalang, Sumatra Barat

Authors: Azmi Renaldi Alrahmadana*, Hamdi Rifai*, Syafriani, Fatni Mufit dan Nofi Yendri Sudiar

Abstract:  Volcanic soil is a part of interest for physical, chemical, and morphology studies of soil derived from volcanic ash, which is known to be fertile and is one of the most productive soils in the world. They are also known to have a high environmental carrying capacity, as evidenced by the dense population in the area around the volcano. The soil contains many minerals, one of which is magnetic minerals. However, there is no document so far that records the value of the magnetic susceptibility of volcanic soil on the surface of Mount Singgalang. This study aims to determine the abundance of magnetic minerals based on their magnetic susceptibility values. To achieve this goal, the rock magnetism method is applied with the Bartington magnetic susceptibility meter type MS2B sensor instrument. Magnetic susceptibility values can be used as initial characteristics to understand past volcanic processes and explain environmental changes. This method is very effective, inexpensive, sensitive, fast, and non-destructive. The results showed that the value of the magnetic susceptibility of volcanic soils varied with a value range of 93.3 - 352.5 (x10−8 m3/kg). Based on this value, it is assumed that the magnetic mineral properties are antiferromagnetic. The average frequency dependent susceptibility (χfd) (%) ranges from 0.831 - 2.090 %, indicating that the measured volcanic soil contains almost no superparamagnetic grains and is generally dominated by multi-domain grains.

Title: Fabrication of Polyaniline Thin Film Using Electrodeposition Method as Alcohol Sensor

Authors:  Ana Yuli Komariyah*, Nugrahani Primary Putri

Abstract: The use of aliphatic alcohols such as methanol as an alternative renewable fuel in high-density engines can harm both the environment and human health. Polyaniline (PANi), a conductive polymer, has emerged as a solution to this problem because of its benefits as a sensor with relatively high conductivity. In this study, PANi was synthesized using a potentiostat electrodeposition method at a constant potential of -0.4 to +1.0 V at a scan rate of 100 mV/s, resulting in a thin film of PANi on the ITO surface. The formed PANi samples were used to determine the sensitivity level of the sensor to methanol at different concentrations. Morphological results of PANi deposited on the ITO surface were observed using SEM showing the shape of nanoparticles with an interconnected-sponge structure and a porous shape with a diameter of 35.3 nm. The PANI sample can be applied as a sensor material for detecting alcohol vapour in indoor air (at room temperature). The sensing measurement results show that the PANi-based sensor can detect methanol vapour at low concentrations up to 5 ppm. The higher the methanol concentration used, the higher the sensor sensitivity.

Title: Design and Implementation of Non-Contact Infrared Thermometer based MLX90614 and Ultrasonic Sensors

Authors: Inayatul Inayah, Heri Kiswanto, Achmad Dimyati, and Muhammad Ghofinda Prasetia

Abstract: : Measurement of body temperature is essential to know the condition of the individual’s body. Temperature measurements need to be carried out without contact between individuals and devices or individuals with other individuals to prevent the transmission of Covid-19. In this study, a non-contact thermometer has been designed using an MLX90614 sensor to measure body temperature, and an HC-SR04 ultrasonic sensor to detect objects at 5-30 cm. The sensor reading results will be displayed via the TFT LCD in real-time. If the detected object temperature exceeds 37.5 oC, the buzzer will sound, and the LED will light up. The constructed thermometer is supplied by 12 V DC adapter to provide 5 V output to the microcontroller. Proximity sensor, temperature sensor, and TFT LCD work on 5 V DC voltage. A Resistor and a transistor were needed to turn on the LED and 12 V high decibel buzzer. This instrument has been tested and compared with a commercial thermometer AD801 model for measuring palms and forehead. Based on our study, the difference in palm and forehead temperature readings between the two thermometers in two individuals ranges from 0 to 0.2 oC. This reading error was still within the tolerance of the reading error listed on the MLX90614 sensor datasheet, which is ± 0.3 oC.





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