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Modelling analysis of high effect of roll hoop main on the strength of student car formula chassis

Tamjidillah M., Subagyo R., Isworo H., Nanlohy H. Y.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 100, nr 1

26--40

EN

Purpose: To analyse the strength of materials by means of optimization, find the best value of the strength test of mutually influential materials with a variation of roll-hoop height. Design/methodology/approach: The research began with the design of a threedimensional model by varying the height of the roll-hoop on chassis types: A, B, C, D, E, F, G, H ,and I. The height of the main roll hoop at each chassis is: 502, 504, 506 508, 510, 512, 514, 516 and 518 mm. Then by using the student version of Autodesk Inventor, a simulation is made to test: Deflection, Normal stress, Shear stress (T-x / T-y) and Torsional stress. The results of this test are used to analyse the types of chassis that have been designed so that the best chassis design is obtained. Findings: The results obtained in this study are the value of Normal stress decreases with increasing roll-hoop height, and applies inversely to the torsional stress value. Deflection values tend to be stable with increasing roll-hoop height, while Shear stress T-x and T-y values tend to fluctuate. Research limitations/implications: The chassis material uses carbon steel which has mechanical property values in accordance with 2015 FSAE Standard regulations. Practical implications: The optimization results of the design of the roll hoop height on the chassis show that the chassis type B with the main roll hoop height of 504 mm is the best with the lowest deflection value and the difference in tension according to the FSAE rules. Originality/value: The research that has been done only tests the strength of the ingredients separately. In this study trying to analyse the strength of the material by way of optimization to find the best value from the strength test of material that influence each other with a variation of roll-hoop height.

2

The role of hydrogen gas buble in hydrophobic properties in mixed micro layer (Al2O3+Mg)

Subagyo R., Wardana I. N. G., Widodo A., Siswanto E.

Archives of Materials Science and Engineering

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2020

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Vol. 105, nr 1

5--16

EN

Purpose: To find out more about the role of hydrogen gas bubbles in improving the hydrophobic nature of a layer, especially in the layers of microparticles Alumina (Al2O3) with Magnesium (Mg). Design/methodology/approach: The method used is an experimental method by first conducting the SEM-Edx test, testing the content of the elements in the waxy layer and observing the topographic shape on the surface of the taro leaves. Then prepare a mixture of Alumina micro particles with Magnesium to investigate the hydrophobicity of the taro leaves. The mixed presentations between Alumina and Magnesium are: (0, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%). Findings: The results of this study found three conditions of the Alumina and Magnesium mix layer when in contact with a droplet, namely: Hydrophobic conditions occur when the surface structure of the rough mixed micro layer forms micro crevices, then bubbles of hydrogen gas fill it to form trapped gases. When droplets come in contact with the surface of the mixed layer the effect of the gas being trapped is very effective at creating hydrophobic properties. While the transition conditions occur when more and more hydrogen gas bubbles along with the increasing percentage of Mg and the opposite occurs in micro particle fissures. Bubbles fill the micro-gap space fully so that the tops of the micro particles are covered by bubbles. This causes the droplet surface tension to weaken, so the droplet contact angle decreases. Furthermore, hydrophilic conditions occur when the micro gap is getting narrower as the percentage of Mg increases and the formation of hydrogen gas bubbles increases. The high level of bubble density in the micro gap closes the peaks of the micro particles, which results in the surface tension of the droplet getting weaker. In this weak surface tension condition, the hydrogen bubble can break through the droplet surface tension and change its hydrophobic nature to hydrophilic. Research limitations/implications: This research is limited to the hydrophobicity of Alumina and Magnesium materials, mainly to investigate the role of hydrogen gas in supporting the hydrophobic nature of taro leaves (Colocasia esculenta). Practical implications: The practical implication in this study is the use of hydrophobic membranes which are widely applied to filtration. Originality/value: Discovered the composition of a membrane mixture of Alumina (Al2O3) and Magnesium (Mg) to create hydrophilic and hydrophobic conditions.

3

Modelling study of flue gas flow pattern with pressure, amount and shape variation catalytic converter

Ghofur A., Isworo H., Subagyo R., Tamjidillah M., Siswanto R., Ma’ruf, Purwanto H., Muchsin

Archives of Materials Science and Engineering

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2020

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Vol. 103, nr 1

5--17

EN

Purpose: The purpose of this study is to analyse the modelling of exhaust gas flow patterns with variations in pressure, number, and shape of filters on the catalytic converter. Design/methodology/approach: The research method used is a simulation using ANSYS, which starts by creating a converter catalytic model with pressure variations: (0.5-1.5 atm), number of filters: (2-5), and the form of filter-cut/filter-not-cut. Findings: The decrease in velocity is caused by non-uniform velocity in the exhaust gas flow that occurs when passing through a bend in the filter-cut that serves as a directional flow to create turbulence. Filter-cut type tends to have fluctuating pressure, turbulence flow pattern shape so that contact between filter and exhaust gas is more effective. Based on the analysis of flow patterns, the speed and pressure of the 5 filter-not-cut design at a pressure of 0.5 are the best, while at pressure (1-1.5 atm) the type 5 filter-cut is the best. Research limitations/implications: This study is limited to filter-not-cut and filter-cut types with variations in the number of filters: 2, 3, 4, and 5, and the inlet pressure between 0.5-1 atm. Practical implications: The practical implications of this study are to find a catalytic converter design that has advantages in the effectiveness of exhaust gas absorption. Originality/value: The results show that the filter-not-cut and filter-cut types have the best effectiveness in the number of 5 filters. Filter-not-cut at the pressure of 0.5 atm and filter-cut at pressure (1-1.5 atm).

4

Physical and chemical mechanisms of hydrophobicity of nanoparticle membranes (Mg+Al2O3)

Wahyudi Wahyudi, Subagyo R., Gapsari F.

Journal of Achievements in Materials and Manufacturing Engineering

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2019

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Vol. 96, nr 2

57--68

EN

Purpose: Investigate the hydrophobic, superhydrophobic and hydrophilic properties of Alumina (Al2O3) and Magnesium (Mg) nanoparticles. Design/methodology/approach: This research was conducted by SEM-EDX analysis of Magnesium and Alumina nanoparticles, observation of gas bubbles when droplets of water contact with membrane surfaces, measurement of surface roughness and detection of Hydrogen gas production using Gas Chromatography. There are eleven compositions (Al2O3:Mg) membranes used in this study, namely: (0:100; 10:90; 20:80; 30:70; 40:60; 50:50; 60:40; 70:30; 80:20; 90:10; and 100:0). Findings: Successfully found an alloy membrane between Alumina (Al2O3) and Magnesium (Mg) nanoparticles in the composition of Mg:Al2O3 (0:100%) having Hydrophobic properties; Mg:Al2O3 (50:50%) has Superhydrophobic properties and Mg:Al2O3 (100:0%) has hydrophilic properties. Three conditions occur when H2O droplets come in contact with the membrane layer, namely: hydrophobic conditions when the trapped gas pressure is smaller than the droplet pressure. Superhydrophobic conditions when the trapped gas pressure is equal to the droplet pressure. Hydrophilic conditions occur when the trapped gas pressure is greater than the droplet pressure. Research limitations/implications: This research is limited to the hydrophobic nature of Nano Alumina (Al2O3) and Magnesium (Mg) membrane particles. Practical implications: Superhydrophobic properties are very suitable to be applied to membranes that are useful for destiny. Originality/value: The novelty of this study is to find the right mixture of nanoparticles of Alumina and Magnesium in a composition that is capable of creating hydrophobic, superhydrophobic and hydrophilic properties.