Gravitasi

Subsurface Utility Mapping on SYT Road Segment, Yogyakarta Using Ground Penetrating Radar (GPR) Frequency 500 Mhz

Gresia Ginting, Putu Andika, Andri Paembonan — Tue, 31 Dec 2024 12:59:37 +0000

This research was carried out aimed to detect the presence of subsurface utilities and map the utilities contained in the SYT road segment, Yogyakarta. This aims to prevent damage and leakage when planting new utilities in the future. Ground Penetrating Radar (GPR) method with a frequency of 500 MHz measure in 12 lines, processed using ReflexW. The result shows the utilities consist of cable and pipe utilities. The wires will provide a nested hyperbolic anomaly response, while the pipe provides a single hyperbole anomaly. The continuity anomaly is suspected as a utility network. The continuity is seen based on the depth and dimensions of the hyperbola are similar. The utilities contained in the SYT road segment; Yogyakarta are at a depth of 0.5 m - 2.8 m. Where there is continuity which is suspected as a cable and pipe network.

Acoustic Material Capability of Pineapple (Ananas comosus) Leaf Fibre with PVA (Polyvinyl Alcohol) Adhesive as Noise Absorbent

Maria Antoinet, Nurlaela Rauf, Sri Suryani — Tue, 31 Dec 2024 13:00:25 +0000

Noise is noise pollution that can disturb health if its intensity exceeds the hearing threshold. Acoustic material is one way to control noise. This research uses pineapple (Ananas comosus) leaf fibre as an acoustic material with Polyvinyl Alcohol (PVA) adhesive. The purpose of this research is to measure the value of the sound absorption coefficient using the impedance tube method with variations in composition and thickness. The results showed that for variations in the composition of pineapple leaf fibre with PVA (7:3, 3:1, 8:2, and 6.5 :3.5) at a frequency of 800 Hz, the sound absorption coefficient values were 0.18; 0.17; 0.37 and 0.18, respectively. In the thickness variation (1 cm, 1.5 cm, and 2 cm), the sound absorption coefficient values were 0.47; 0.65 and 0.73, respectively. The results show that the amount of sound absorption in the composition variation and thickness variation has met the ISO 11654 standard.

Measurement of the Sound Absorption Coefficient of Rice Straw (Oryza Sativa) Acoustic Material as Noise Dampener

Yuni Bandhaso, Nurlaela Rauf — Tue, 31 Dec 2024 13:01:11 +0000

This study determines the sound absorption coefficient values of rice straw acoustic material as a noise reducer using the two-microphone impedance tube method based on ISO 10534-2:1998 standards. Two test variables were employed in this research. Composition variation consisting of three samples and thickness variation also comprising three samples. Composition variation was conducted to evaluate the ability of rice straw as a sound absorber, while thickness variation was used to determine the effect of thickness on the sound absorption coefficient of rice straw acoustic material. All test samples obtained the highest absorption coefficient values at a frequency of 1600 Hz. The acoustic material in the composition variation achieved the highest absorption coefficient values of 0.30, 0.34, and 0.37, respectively. The thickness variation obtained the highest absorption coefficient values of 0.73, 0.79, and 0.95, respectively. The obtained sound absorption coefficient values meet the standards established by the International Standardization Organization 11654.

Application of the LEM-Bishop Based on the Generalized Hoek-Brown Criteria for Assessing the Stability of Rock Slopes at Mining Area of PT. Karya Sopai Sejahtera, Palu City

Tue, 31 Dec 2024 13:01:42 +0000

PT. Karya Sopai Sejahtera (PT. KSS) operates in rock mining using an open-pit system in Watusampu, Palu, Central Sulawesi. Excavation alters slope geometry, affecting stability and risking landslides, impacting safety, equipment, and productivity. To address this, a geotechnical study assesses slope stability using the Limit Equilibrium Method (LEM) - Bishop method. Geological surveys and Electrical Resistivity Tomography (ERT) reveal predominantly andesite rock with fresh gray and weathered brown colors, hypocrystalline and equigranular textures, and quartz, pyroxene, biotite, and hornblende minerals. The slope design includes a 150-meter overall height, bench heights of 15-25 meters, widths of 3-5 meters, a single slope angle of 70°, and an overall angle of 61°. Static analysis shows stability (FS 1.94), but dynamic conditions, including earthquakes, reduce FS to 0.43, causing instability (FS < 1.1) with a 100% failure probability. The slope is stable except during strong earthquakes.

Pertamax Quantity Optimization by Controlling Losses Using Vapor Recovery Unit at Fuel Terminal Bandung

Mirza Faris Rahman, I. L. Pratama — Tue, 31 Dec 2024 13:02:22 +0000

This research was conducted at the fuel terminal, a storage and distribution facility for Pertamax fuel, with the aim of addressing Pertamax losses due to evaporation in fixed roof tanks. This evaporation leads to the emission of hydrocarbon vapors, which have a negative impact on the environment. One proposed solution was the use of a Vapor Recovery Unit (VRU), which can capture up to 95% of hydrocarbon vapors and convert them back into liquid form. This study employed the calculation methods of breathing loss and working loss to analyze the efficiency of the VRU in controlling losses. The research findings shows that the VRU was effective in reducing emissions and controlling losses, making the implementation of VRU a recommended strategic step to enhance operational efficiency and reduce environmental impact at the fuel terminal. This research is expected to serve for further studies on optimization of VRU usage in the field

Evaluating the Stability of Red Dragon Fruit (Hylocereus polyrhizus) as Natural Dyes: Impact of Concentration, pH and Storage Duration

Iqbal, Zainuddin Basri, Abyudan Adyatma — Tue, 31 Dec 2024 13:02:53 +0000

This reseach explores the application of Hylocereus polyrhizus extracts as natural dyes, emphasizing anthocyanin content, stability, and light absorption under varying conditions. The findings indicate that undiluted extracts attain maximum light absorption in the 520-550 nm spectrum, aligning with the anthocyanin pigments that impart the fruit's vivid color. Increased dilution results in diminished absorbance, attributable to reduced anthocyanin levels. The research highlights the importance of pH on pigment stability, with optimal absorption at pH 3-4, while elevated pH leads to decreased absorption due to anthocyanin structural alterations. Notably, a rise in absorbance on Day 15 of a 15-day storage period may indicate pigment stabilization, potentially through copigmentation with phenolic compounds. Nonetheless, a general decline in total anthocyanin content across samples is noted, likely influenced by environmental conditions and extraction inefficiencies. This investigation underscores the potential of red dragon fruit extracts as viable, sustainable dye sources for DSSCs and other applications.