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All Journal Journal Of Engineering Sciences (Improsci)
Harmi Tjahjanti, Prantasi Harmi Tjahjanti
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Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Electrical & Electronics Engineering Industrial & Manufacturing Engineering Mechanical Engineering

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Acetylene Welding of Brass Materials for Radiator Cover: A Study on the Weld Quality and Performance Setyo, Nugroho; Harmi Tjahjanti, Prantasi Harmi Tjahjanti
Jurnal Improsci Vol 1 No 1 (2023): vol 1 No 1 Agustus 2023
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v1i1.28

Abstract

Brass material is important for all industrial parts. Brass had good ability work in cold or hot conditions, in solid state CuZn is capable of dissolving more crystals in the mixture. At temperatures of 902°C peritectic transformation occurred where Zn soluble in 32.5%. Solubility is increased up to a temperature of about 450 ° C to 39% and then in equilibrium will decrease, the length of the heating and cooling process is very long. With descriptive technique showed that the weld strength brass highest (7863.1 kgf / mm2) is that the surface of the specimen suffered welding rubbing with a gap distance of 0.2 and 0.3 mm, both with water cooling or air cooling, and the condition other relatively much lower strength (3144.89 kgf / mm2). Welding the workpiece surface is not polished strength is low. Specifically, properties - mechanical properties of brass can be improved by the addition of small amounts of other alloying elements without reducing the characteristics of the brass in general. But with a maximum limit zinc levels should not exceed 42% because it will result in a brass are fragile because of excess levels of zinc, and cannot be used commercially. with the addition of other elements as reinforcing elements of brass such as silicon, bismuth, selenium and others to improve the ability of the brass in the machining process. Welding results by using three different types of welding wire shows that, at the time of welding is performed with brass welding wire in the market there is no trouble found. Welding speed specimen is also calculated using a stopwatch, and the speed required for welding in 3 specimens, the average in the first specimen takes 5 minutes for the welding process. And the visual results produced is also satisfied.
Electric Wheelchair Manufacturing Analysis For Physical Disabilities Reviewed from the Aspect of Ergonomics Harmi Tjahjanti, Prantasi Harmi Tjahjanti; Mulyadi; Iswanto; Artha Gumelar, Buyung; Rudyansyah Christie, Rakhmad; Prastio, Anggit; Mustakim, Annas
Jurnal Improsci Vol 2 No 1 (2024): Vol 2 No 1 August 2024
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v2i1.429

Abstract

The high rate of physical disability is a trigger and spur in the development of research/research for people with disabilities to help with their daily activities, one of which is with a wheelchair. There is a sense of concern to see manual wheelchairs used daily by people with physical disabilities, especially with their abnormal hands and feet, so it becomes a problem in itself because they are quite tricky and tired of pedaling a manual wheelchair. This condition impacts their work productivity, thereby reducing their income/economy. Therefore, the purpose of this research is to manufacture electric wheelchairs belonging to two people with physical disabilities (i.e., belonging to Bagus and Huda). The ergonomics tests are carried out, including (a) Compatibility of the anthropometry of the user's body and the dimensions of the wheelchair, (b) Results of the user's postural analysis with RULA (Rapid Upper Limb Assessment) (c) Conformity of the dimensions of the wheelchair with the standard, and (d) Evaluation of the usability of the wheelchair based on observation. The results obtained for the Bagus electric wheelchair are from the anthropometric side. The popliteal height is longer than the distance between the seat and the footrest in the wheelchair. For Bagus to be more comfortable in using his wheelchair and for his legs not to be crooked (which will potentially cause more excellent musculoskeletal disorders), it is recommended that the distance between the seat and the footrest be extended. As for Huda electric wheelchairs, in general, they have been modified to adjust to the needs and conditions of Huda's body and make the design of Huda wheelchairs more ergonomic. However, the postural analysis showed that the forearm position was raised, and the hand was twisted when Huda operated the electric wheelchair controller. It is, therefore, recommended to lower the position of the controller in line with the wheelchair mount.
Core Material Manufacturing Study On Aluminum Composite Panel (ACP) Harmi Tjahjanti, Prantasi Harmi Tjahjanti; Fahruddin, A'rasy; Mulyadi, Mulyadi; Hardy Sujiatanti, Septia; Eryandrie Wicaksono, Majdi; Bamban Jakaria, Ribangun
Jurnal Improsci Vol 2 No 3 (2024): Vol 2 No 3 December 2024
Publisher : Ann Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62885/improsci.v2i3.579

Abstract

An aluminum composite panel (ACP) is a flat panel with aluminum plates/sheets that are rigid and strong but relatively lightweight. Between the two plates, the core material content is generally made of polyethylene and polyurethane. However, the two core materials are not resistant to high temperatures/heat. They are flammable, so it is urgent to make variations of other core materials resistant to high temperatures. This study aims to provide variations for ACP core materials using polymer materials resistant to high temperatures, namely Low-Density polyethylene (LDPE) and Polyoxymethylene (POM). The method used is experimental/fabrication of ACP making. The high-temperature test was carried out in a furnace with a temperature of 3000C, 3500C, and 4000C, each with a holding time of 1 hour. The results obtained from observing the microstructure using an Optical Microscope before and after the test damaged the core material while the Aluminum metal was still intact. The mass of ACP before and after testing also changed. Overall, at the three temperatures above, the LDPE core material does not withstand this temperature because the temperature is above the melting point of the LDPE material.
Co-Authors Artha Gumelar, Buyung Eryandrie Wicaksono, Majdi Fahruddin, A'rasy Hardy Sujiatanti, Septia iswanto MULYADI Mulyadi Mulyadi Mustakim, Annas Prastio, Anggit Ribangun Bamban Jakaria Rudyansyah Christie, Rakhmad Setyo, Nugroho