PERANCANGAN GIRDER PADA FLEKSIBEL GANRTY CRANE KAPASITAS 1 TON

Lifting and transporting equipment is one of the keys to carrying out work in the manufacturing and construction industries. Due to limited access, various obstacles must be overcome in some working areas. A ganrty crane is an alternative lifting equipment that has high flexibility. This article reports the research results on the girder’s main components. This component gets direct contact with loading when lifting and rigging work is carried out. This research method was conducted by comparing manual calculation models and CAE using the Solidworkss Simulation software. From these two methods, this study yielded 23.091 and 25.54MPa for manual calculations and the finite element method, respectively. Furthermore, in the finite element method with direct contact loading, a stress of 40.52MPa is obtained. From the three stress calculations, it can be concluded that the safety factor has exceeded the requirements set out in the standard. Furthermore, utilizing the Goodman model, mitigating the possibility of fatigue failure also indicates a safe condition. Based on recent research reports, a potential self-healing is not yet possible to be recognized well especially for metals having a grain size of micron

Evaluation Of Subcooling With Liquid-Suction Heat Exchanger On The Performance Of Air Conditioning System Using R22/R410A/R290/R32 As Refrigerants

This paper presents a numerical study to investigate the effect of subcooling with liquid-suction heat exchanger (LSHX) on the performance of air conditioning system using R22, R410A, R290 and R32 as refrigerants. In the near future, R290 and R32 refrigerants are projected to replace R22 and R410A as working fluids in the residential air conditioning. In this study, four parameters, i.e., the refrigerating effect, compressor work, COP and discharge temperature were investigated. In the numerical modelling, the evaporating and condensing temperatures were assumed constant at 5 oC and 40oC, respectively. The results showed that the COP improvements increased with the increase in the subcooling. R32 and R290 had the lowest and the highest COP improvement when subcooling was applied, i.e., 3.3% and 5.3% for subcooling of 5K and 6.2% and 10.2% for subcooling of 10K, respectively. Due to low global warming potential and almost identical refrigerant properties as compared to R22, system with LSHX and R290 has huge commercial potential as a replacement for conventional system in the futur

Limestone Industry on PM2.5 Air Quality in Padalarang and Surrounding Areas

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