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All Journal Mekanika: Majalah Ilmiah Mekanika ASEAN Journal of Chemical Engineering International Journal of Applied Technology Research Jurnal Polimesin
Tritjahjono, Rachmad Imbang
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Aerospace Engineering Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics

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Limestone Industry on PM2.5 Air Quality in Padalarang and Surrounding Areas Yuningsih, Nani; Simbolon, Luga Martin; Hidayat, Syarif; TRITJAHJONO, Rachmad Imbang; Sumeru, Husain Akbar; Raji, Lukman
Jurnal Internasional Penelitian Teknologi Terapan Vol 5 No 1 (2024): February 2024
Publisher : Bandung State Polytechnic (Politeknik Negeri Bandung)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35313/ijatr.v5i1.140

Abstract

The processing of limestone through the combustion process will cause air pollution at the combustion site and its surroundings. At the limestone processing site, Padalarang experiences relatively high air pollution. PM2.5 is one of the main pollutants produced by limestone burning, so it is very necessary to study the concentration of PM2.5 in the air in Padalarang and its surroundings. This study was conducted in Padalarang and its surroundings, where data collection was carried out in five locations, namely at the center of limestone burner, 1 km, 2 km, 3 km, and 4 km to the east of the burning center. Data collection was carried out for ten days, where each data collection was carried out for 12 hours, from 07.00 to 19.00. Based on the national standard of PPRI No. 22 of 2021, which is 55 µg/m3, the concentration in the limestone burning center and 1 km from burning center have exceeded the standard, which is 82.5 and 69.3 µg/m3. While PM2.5 concentrations at distances of 2 km, 3 km, and 4 km are below the national standard, namely 52.0, 51.6 and 50.2 µg/m3, respectively. Based on the Air Quality Index (AQI), the AQI at the burning center, distance of 1 km, 2 km, 3 km, and 4 km are Unhealthy, Unhealthy, Moderate, Moderate and Moderate, respectively. This means that areas less than 1 km away are not healthy places to live. The poor air quality in Padalarang is reflected in the much higher number of ARI cases compared to the surrounding sub-districts that do not have a limestone industry.
The Efficiency of κ-Carrageenan-Chitosan-PVA-MWCNTs Membranes in Removing Methylene Blue, Rhodamine B, Bromocresol Purple, and Murexid from Water Widarti, Sri; Suprianti, Yanti; Kurniasetiawati, Annisa Syafitri; Tritjahjono, Rachmad Imbang
ASEAN Journal of Chemical Engineering Vol 23, No 3 (2023)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ajche.78794

Abstract

The electrocoagulation method has been proven to be highly effective in removing metal ions from water, with a removal efficiency of over 97%. However, in terms of removing organic pollutants such as synthetic dyes, the efficiency of electrocoagulation is still relatively low. A hybrid approach combining electrocoagulation with membrane filtration has been proposed to enhance the removal of organic contaminants. Eco-friendly membranes made from renewable natural polymers like carrageenan and chitosan, reinforced with synthetic polymers such as polyvinyl alcohol and carbon nanotubes, have shown to be promising for this application. In this study, membranes with varying chitosan/carrageenan ratios of 0.2, 0.33, 0.5, and 0.71 (g/g) were used to remove synthetic dyes, including methylene blue, rhodamine B, bromocresol purple, and murexid, at a concentration of 200 ppm from 8.5 ml of water. From the SEM images, the four membranes have almost the same surface and cross-section morphology. The results showed that the membrane with a chitosan/carrageenan ratio of 0.71 exhibited the highest removal efficiency for all synthetic dyes. The parameter affecting the membrane’s removal efficiency is the interaction between the membrane and synthetic dyes. Murexid, an anionic dye, achieved a 100% removal efficiency, surpassing cationic dyes such as rhodamine B and methylene blue. Besides interactions, the dye’s molecular size determines the removal’s efficiency. The molecular size of rhodamine B is larger than that of methylene blue, and the removal efficiency of rhodamine B (98.4%) is greater than methylene blue (91%). Bromocresol purple is almost the same size as rhodamine B but not ionic because it has the lowest removal efficiency of 34.55%.
Energy savings in residential air conditioners using condensate cooling in discharge and liquid lines Yuningsih, Nani; Sumeru, Kasni; Aldiansyah, Muhammad; Tritjahjono, Rachmad Imbang; Nugraha, Fathurahman Yudhi; Abioye, Adenkunle Moshood
Jurnal Polimesin Vol 23, No 4 (2025): August
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v23i4.6739

Abstract

This research investigates the use of condensate produced by the evaporator to cool the discharge and liquid lines in order to reduce electricity consumption in a residential split-type air conditioner (AC). The experimental setup used a 0.75 kW compressor with R32 refrigerant, where the discharge and liquid line heat exchangers were 20 cm and 15 cm long, respectively. Data were collected over 180 minutes at 5-minute intervals. Results show that using the liquid line cooler (LLC) alone reduced electricity consumption by 5.3% and increased cooling capacity by 2.3%. Using the discharge line cooler (DLC) alone reduced electricity consumption by 8.3% and increased cooling capacity by 7.3%. When both coolers were applied simultaneously (LDC mode), electricity consumption decreased by 10.9% and cooling capacity increased by 9.7%. The corresponding improvements in coefficient of performance (COP) were 9.1% (LLC), 18.6% (DLC), and 24.7% (LDC). These results indicate that using condensate to both the discharge and liquid lines is more effective in reducing electricity consumption and improving AC performance than cooling only one line.
Analisys of Tensile Strength, Wear Rate, and Cristallinity of Biocomposite Nano-HA/Magnesium/Shellac Reinforced Cantula Fiber for Bone Screw Material Utami, Dea Pawestry; Triyono, Joko; Raharjo, Wijang Wisnu; Tritjahjono, Rachmad Imbang
Mekanika: Majalah Ilmiah Mekanika Vol 23, No 1 (2024): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v23i1.71127

Abstract

Accidents are a major cause of fractures in Indonesia. One of the treatments for fractures is bone screws with support plates that are placed on broken bone. Currently, many biomaterials for bone screws are being developed which have biodegradable properties so that post-operative bone healing is not required. The purpose of this study was to determine the effect of cantula fiber addition on tensile strength, wear rate, and crystallinity of nano-HA/magnesium/shellac bio-composite for bone screw materials. Nano-HA/magnesium/shellac/cantula fiber materials were mixed using a blender. The material was mixed with a magnesium/hydroxyapatite ratio of 70/30 and cantula fiber was added with variations of 0%, 10%, 20% and 30% of total volume. After that, material mixture was compacted with a pressure of 300 MPa for 10 minutes. Then sintering process was carried out at temperature of 140 °C for two hours. The results showed that the highest tensile strength value was 7.86 MPa at 30% variation. The lowest wear rate was 0.31 x 10-3 mm3/Nm at 30% variation. The highest crystallinity in X-Ray Diffraction observations was obtained at 30% variation, which was 79.65%.
Co-Authors Abioye, Adenkunle Moshood Aldiansyah, Muhammad Joko Triyono Kasni Sumeru KURNIASETIAWATI, ANNISA Nani Yuningsih, Nani Nugraha, Fathurahman Yudhi Raji, Lukman Simbolon, Luga Martin Sri Widarti, Sri Sumeru, Husain Akbar Syarif Hidayat Utami, Dea Pawestry Wijang Wisnu Raharjo YANTI SUPRIANTI, YANTI