Energy, Materials and Product Design

ANALISIS RISIKO KERJA PADA PROSES PEMBUBUTAN MENGGUNAKAN METODE HIRARC

Fikrihadi Kurnia — 2023-11-30

Poor management of occupational safety and health (OSH) has an impact on occupational accidents. This results in losses for both the individual worker and the company. Therefore, the occupational hazard accident risk analysis was carried out using the HIRARC (Hazard Identification Risk Assessment and Risk Control) method. Data collection was conducted from the business owners of SSBC (Sanggar Sarana Baja Cakra) Welding and Turning Shop, located in Cakranegara, Mataram, West Nusa Tenggara. There are 3 work activities for risk identification, namely the clamping process, the engraving process and the drilling process. The results of the analysis show that the highest level of occupational risk occurs during clamping and engraving process. For drilling, it's in low level of risk. As for risk management, it is mainly done for high-risk level. Immediate improvement is needed by providing personal protective equipment (PPE) to workers to reduce these risks. Based on these results, business owners can do evaluation on his business so occupational accidents can be in the workplace.

ANALISA PENGARUH KAMPUH PENGELASAN DAN PERLAKUAN PANAS TERHADAP SIFAT MEKANIK SAMBUNGAN LAS BAJA SUP9

I Made Mara — 2023-11-30

The development of science and technology which is growing rapidly greatly affects industries that produce machine elements that use steel as the main raw material, steel is widely used in construction. This has caused many mechanics to join steel using the SMAW process without regard to the welding method and mechanical properties which causes the steel not to be connected perfectly, thereby endangering safety. The purpose of this study was to see the effect of seam variation V, K and X and normalizing, quenching and no heat treatment on the mechanical properties of welded joints in SUP9 steel. From the variation of seam and heat treatment, there were 9 combinations with 3 repetitions. The results of this study indicate that the weld seam and heat treatment affect the tensile strength and impact price of SUP9 steel. The most optimal treatment to produce high tensile strength is seam variation X with quenching heat treatment with ASTM E8 specimen shape having an average tensile stress value of 84.23 Kgf/mm², and for the most optimal treatment to produce high impact values is variation of seam X with normalizing heat treatment with specimen form ASTM E23 has an average impact value of 1.11 J/mm².

PENGARUH VARIASI pH DAN RAGI TERHADAP VOLUME DAN KADAR BIOETANOL DARI BAHAN MOLASE

Nurchayati — 2023-11-30

Energy is a necessity in carrying out economic activities in Indonesia, both for consumption needs and production activities in various business sectors. As a natural resource, energy must be used optimally for the benefit of society and its management must be based on the principles of sustainable development. Bioethanol is a renewable and environmentally friendly energy that can be used as an alternative to fossil fuels. The use of bioethanol as fuel has several advantages, namely the high oxygen content of bioethanol (35%) so that it can produce clean fuel. The purpose of this study was to determine the effect of variations in pH and yeast on the volume and content of bioethanol from molasses material using and the drying time used was 48 hours. From variations in pH and yeast, 9 types of treatment were obtained with 3 repetitions so that the total sample was 27. From the results of the study, the average volume of alcohol produced was at most 550.67 ml in the yeast mass treatment 10 gr/l with a pH of 4.5 and the least was in the yeast mass treatment 15 gr/l with a pH of 4.2 of 432 ml. Whereas the highest average yield was 91.67% for yeast mass of 10 gr/l with a pH of 4.2 and the lowest was found for yeast mass of 15 gr/l with a pH of 4.8 of 88.33%.

SIFAT TEKAN DAN BENDING PANEL SANDWICH BETON RINGAN SELULAR DENGAN PENGUAT PIN BAMBU

Agus Dwi Catur — 2023-11-30

Bamboo plants are a type of grass with hollow segments in the stems, cylindrical, hard and in each book has buds or branching eyes. This bamboo plant can grow around 1200 meters above sea level and lowlands with humidity conditions and broad soil types. This plant is often found growing wild around river banks, forests, or fields. This plant is used by the community to make matting, bamboo bridges, concrete reinforcement, and so on. Concrete is a mixture consisting of sand, gravel or crushed stone and other aggregates mixed together with a paste made from a mixture of cement and water to from a rock-like mass. Lightweight concrete is concrete with a weight of less than 1900 kg/m³. The value of compressive strength is smaller than ordinary concrete and is not good at conducting heat. The specific gravity of lightweight concrete varies greatly depending on the lightweight aggregate used. Sandwich components are a type of structural composite that has the potential to be developed. Sandwich composite is a composite composed of 3 layers consisting of a flat composite (metal sheet) as the surface skin (skin) and the core material (core) in the middle (the part between). Sandwich composite is a type of composite that is very suitable for resisting bending, impact, vibration and sound dampening. Sandwich composites are made to obtain a lightweight structure but have high stiffness and strength. Usually the selection of sandwich composites materials, the requirements are light weight, heat and corrosion resistance, and price is also considered.

The purpose of this study is to utilize the addition of bamboo as a concrete reinforcement instead of steel, to create a very affordable cost and to find out how much influence the addition of bamboo pins has as a core reinforcement in sandwich composites on the compressive and bending strength of the lightweight concrete. The variation of the spacing of the bamboo pins used is 3 cm and 4 cm for the width, and 4 cm 6 cm for the length of each sandwich composite. The size the sandwich composites varies, while for compression testing it has a length of 15 cm, a width of 15 cm and a thickness of 7,5 cm. And for the bending test it has a length 40 cm, a width of 10 cm, and a thickness of 7,5 cm.

The results showed that there was an increase in strength in the compressive test from those who did not use pins of 0,646 N/mm², and those who used pins with a distance of 3 cm x 4 cm of 1,94 N/mm² and a distance of 4 cm x 6 cm of 1,596 N/mm². Where the longer the distance between the bamboo pins, the strength decreases. For the bending test it also shows an increase from without pins having a value of 0,43 N/mm² to adding pins with a pin spacing of 3 cm x 4 cm having a value of 0,89 N/mm² and experiencing a decrease in pin spacing of 4 cm x 6 cm with a value of 0,25 N/mm².

PENGARUH PROSES PACK NITRIDING TERHADAP ANGKA KEKERASAN PERMUKAAN, KEULETAN DAN STRUKTUR MIKRO PADA BAJA SS 400

Sujita — 2023-11-30

The pack nitriding process is a process of increasing the surface hardness of steel by using nitrogen with the help of organic compounds as a nitrogen source in the process.

The processed steel is put into a vessel which is usually made of ceramic, glass or aluminum along with a compound used as a nitrogen source.

During heating,The organic compounds used in the analysis process are generally stable at temperatures up to 570 oC and removal times of 2 to 16 hours. The purpose of the pack nitriding process is to increase the surface hardness while remaining ductile inside. In this study, nitrogen was added using a pack nitriding process after which it was quenched using water. The elimination times used were 4 and 6 hours with temperature variations of 560°C, 580°C and 600°C and presenting nitrogen for the 150 gram pack nitriding process. The highest hardness value was obtained at 580 °C with a surface hardness value of 234.84 kg/mm² with 4 hours of removal time. And the highest impact value was shown by the specimen without treatment of 158.3 Joules. The results of testing the chemical composition of the specimens without treatment and after the pack nitriding process showed that there was an increase in the nitrogen element.