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The Effect of Curing and Leaves Cutting in Longterm Storage of Shallot

IOP Conference Series: Earth and Environmental Science 2020年第1期542卷

作者： M Kusmali U Ahmad E Darmawati Postharvest Technology Study Program Graduate School IPB University Bogor Indonesia Mechanical and Biosystem Engineering Department IPB University Bogor Indonesia

Shallot is important as one of the spices for cooking various foods, as raw materials for the food industry, and as one of the ingredients for Indonesian traditional herbs. Postharvest handling is needed to extend its shelf life and to maintain its quality during storage. The aims of this research are: 1) to evaluate the effect of curing and leaves cutting on the quality changes of shallots during storage, and 2) to get the best pre-storage procedure in maintaining the quality of shallots during storage. Shallots leaves were cut before drying while the others are stored with leaves as control. Then, half of the samples were cured for three days, and sundried for four days, while other samples were sundried directly for seven days without curing them first. Then samples were stored for 16 weeks in two different conditions. The results showed that the treatment of curing without leaves cutting and stored at 5°C with 65-70% RH gave the best quality than other treatments. It could minimize damage and weight loss, maintaining hardness, color, and important ingredients until 12 weeks of storage. However, there were drastic decreases in some quality parameters, 32.0% damage and 38.7% weight loss after 16 weeks of storage.

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Experimental study of the effect of adding prismatic fin to the air flow under v-corrugated absorber plate for solar air heater performance

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AIP Conference Proceedings 2018年第1期1983卷

作者： Mohammad Hakam Djatmiko Ichsani Budi Utomo K. W. Wawan A. W. Clarissa Suroso 1Mechanical Engineering Department of Sepuluh Nopember Institute of Technology Surabaya - Indonesia 2Safety Engineering Study Program of Shipbuilding Polytechnic of Surabaya – Indonesia

One of the easiest alternative energy to get in Indonesia is solar energy. Solar energy can be applied to solar air heater in many industries. With using the radiation of solar energy to be absorb by absorber plate, solar air heater transfers heat in convection to the fluid under the absorber plate. Thermal efficiency of solar air collector can be improved by increasing the absorption area wider by adding prismatic triangle fin. Experimental sets to test the effect of fin addition to solar collector’s performance and efficiency. The experiment uses v-corrugated absorber plate and 30° bill shaped obstacle with fin addition. The geometry of the fins is prismatic triangle fin where fin thickness is 3 mm, with 0.5L spacing between obstacles. Intensity of radiation are varied from 431; 575; 719 W/m2, respectively, and mass flow rate are varied from 0.002; 0.004; 0.006; and 0.008 kg/s, respectively. The result of experimental study, the highest efficiency is 91.77 % achieved by 0.008 kg/s mass flow rate and radiation intensity 431.372 W/m2.

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Exact constructions of a family of dense periodic packings of tetrahedra

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Physical Review E 2010年第4期81卷 041310-041310页

作者： S. Torquato Y. Jiao Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Center for Theoretical Science Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA School of Natural Sciences Institute for Advanced Study Princeton New Jersey 08540 USA Department of Mechanical and Aerospace Engineering Princeton University Princeton New Jersey 08544 USA

The determination of the densest packings of regular tetrahedra (one of the five Platonic solids) is attracting great attention as evidenced by the rapid pace at which packing records are being broken and the fascinating packing structures that have emerged. Here we provide the most general analytical formulation to date to construct dense periodic packings of tetrahedra with four particles per fundamental cell. This analysis results in six-parameter family of dense tetrahedron packings that includes as special cases recently discovered “dimer” packings of tetrahedra, including the densest known packings with density ϕ=40004671=0.856347…. This study strongly suggests that the latter set of packings are the densest among all packings with a four-particle basis. Whether they are the densest packings of tetrahedra among all packings is an open question, but we offer remarks about this issue. Moreover, we describe a procedure that provides estimates of upper bounds on the maximal density of tetrahedron packings, which could aid in assessing the packing efficiency of candidate dense packings.

关键词： constructions family tetrahedra tetrahedrons family Dense Platonic solid

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Analysis of Welding Strength S45C Material in Spot Welding Process with Variations in Welding Press Time and Electrode Diameter

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IOP Conference Series: Materials Science and engineering 2020年第1期1007卷

作者： Sobron M.Lubis Rosehan Styven Erlely Study Program Mechanical Engineering Engineering Faculty Universitas Tarumanagara Jl. Let.Jen S. Parman No.1 Jakarta 11440 Indonesia

Spot welding is one system of connecting to steel materials or other materials that make up sheets. The welding time and electrode diameter are the factors that determine the formation of welding nuggets. This study was conducted to analyze the effect of welding time and electrode diameter on the joint strength of the S45C steel plate with a thickness of 1 mm. The welding process takes place with variations in welding time lasting 1 second, 1.5 seconds, 2 seconds, 2.5 seconds, 3 seconds, and variations in the electrode diameter of 6 mm, 8 mm, 10 mm. The results of welding are then carried out a tensile test to determine the strength of the formed nugget. From the data obtained, an analysis is performed. The highest output voltage analysis result of a 6 mm electrode diameter is 0.92 V with a welding time of 1.5 seconds, 8 mm electrode diameter is 0.9 Volt with 2 seconds welding time and a 10 mm electrode diameter is 0.98 Volt with welding time 1 second. The results of the highest electric power analysis of the 6 mm electrode diameter were 9655.12 Watt with 3 seconds welding time, 8 mm electrode diameter was 9227.66 Watt with 3 seconds welding time, and 10 mm electrode diameter was 9260.64 Watt with 3 seconds welding time. The highest tensile stress analysis results were 20.97 N/mm2 at 6 mm electrode diameter, 21.7825 N/mm2 at 8 mm electrode diameter and 29.555 N mm2 at 10 mm electrode diameter

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Analysis of the use of biogas fuel from palm oil waste as a gas engine (electrical generator)

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AIP Conference Proceedings 2021年第1期2342卷

作者： Rahmad Samosir Budiarto Andreas Kristiawan Mechanical Engineering Study Program Faculty of Engineering Universitas Kristen Indonesia Jakarta Jl.Mayjen Sutoyo no.2 Cawang East Jakarta 13630 Indonesia

An analysis of the use of biogas fuel from palm oil waste has been carried out o produce mechanical energy, including moving generators that produce electricity. In this study two different types of gas are used, namely natural gas and biogas obtained from palm oil waste. This test aims to analyze what the impact of each gas on the performance of the gas engine both in terms of electricity output, fuel consumption and efficiency level. The low calorific value of natural gvvas is 9424 kKal / Nm 3 (39,458 kJ / Nm3 and from the test results the power generated is 10.169 kWh / Nm3 while for biogas the power is 6.062 kWh / Nm3, then the low heating value of biogas is 10.169 kWh / Nm3 while for biogas the power is 6.062 kWh / Nm3, then the low heating value of biogas is obtained. 5615 kJ / Nm3 40.32% lower than the low heating value (LHV) of natural gas. From the results of the analysis it was concluded that the biogas from palm oil waste fulfills the requirements as engine fuel.

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Hot forgeability of SCr420 low-alloy steel for piston rod application

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Journal of Physics: Conference Series 2020年第1期1595卷

作者： L Anggraini H Kartomi Study Program of Mechanical Engineering President University Jl. Ki Hajar Dewantara Jababeka Education Park Cikarang Bekasi 17550 Indonesia

Microstructure development and mechanical property of SCr420 low-alloy steel (equivalent to AISI 5120) obtained by the forging process have been investigated. The relationship between the forgeability and mean grain sizes were examined. The type of forging was carried out by die-forging at a temperature of around 1150 - 1190°C using a machine tonnage of 1600 tons capacity with 2 times forging variation. The high aspect ratio can be maintained through the steel forming applied for piston rod by the hot forging process. Vicker's hardness mechanical tests in initial and forged conditions were carried out at room temperature. The results demonstrate that the Vickers hardness of initial condition of 254.5 HV is much higher in comparison with the hot-forged material of 152.6 HV. The forged low-alloy steel processes the desired ferrite-pro eutectoid and pearlite microstructures, when followed by normalizing process, and deformation are achieved.

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Numerical investigation of heat transfer and fluid flow characteristic of V-corrugated plate solar air collector with prismatic fin as an extended surface

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AIP Conference Proceedings 2016年第1期1778卷

作者： Mohamad Hakam Djatmiko Ichsani Clarissa Suroso 1Mechanical Engineering Department of Sepuluh Nopember Institute Of Technology Surabaya - Indonesia 2Safety Engineering Study Program of Shipbuilding Polytecnic of Surabaya – Indonesia

As the time goes by, fossil energy consumption is increasing. Absolutely, It will cause the decreasing on fossil energy. Because of that it is essential to look for renewable energy, for example is solar energy. Solar energy can be implicated on solar air collector. Solar air collector consists of absorber plate, ducting channel, cover glass, and blower.A numerical investigation of heat transfer and fluid flow characteristics in v-corrugated plate solar air collector having prismatic fin on the absorber plate is presented in this study. Three-dimensional simulations are conducted using FLUENT 6.3.26 and SST-Kω turbulence model. The computations are performed for different fin dimension with a varying thickness and spacing of fin. Simulations were used to find the optimal thickness of the 3mm, 4mm, and 5mm fin with 0.25ℓ, 0.50 ℓ, and 0.75 ℓ spacing between the obstacle on each thickness variation. The effects of the fin dimension and spacing on pressure drop and pressure difference are obtained and analyzed. As the result, using fin on the plate absorber enhanced the heat transfer. The maximum value of the thermal performance parameter was found in 3 mm fin thickness and 0.50ℓ spacing with ΔP/ΔT 37.0672 compared to solar air collector without fin. Presence of prism fin generate turbulence in the flow that obviously increase the heat transfer, but it also gives effect on the pressure drop along the ducting channel.

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Multiple Linear Regression Analysis On Effect Of Time Variations And Voltage Variations On Spot Welding Against Shear Strength Of Aa5083 Material Using Ibm Spss Application

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IOP Conference Series: Materials Science and engineering 2020年第1期1007卷

作者： Gugun Wiranto Sobron Y Lubis Rosehan Study Program Mechanical Engineering Engineering Faculty Universitas Tarumanagara Jl. Let.Jen S. Parman No.1 Jakarta 11440 Indonesia

Spot welding is one type of welding that is quite widely used in the vehicle industry, as well as ship manufacturing. This study used AA5083 aluminum plate which has a thickness of 1 mm, and overlapping joint. This study examine the effect of voltage and time variations on the value of the shear strength of the welded joint. The material is cut with a size of 200mm x 40mm, welded with voltage variations of 1.75V, 2.2Vand 2.28V. And time variations between 1s, 1.5s and 2s, 300Nconstant pressure and uses copper electrodes with a diameter of 8mm. Multiple linear regression analysis is carried out and the effect of variabel X1 (stress) + X2 (time) on Y (shear strength) is 50.4%, where X1 is 22.7% and X2 is 27.8%. It states that there is no influence between X1 and X2 on Y, because the more dominant data is the data at 1.75V and 2.2Vvoltages which have no significant difference. At 2.28V the material will receive more heat so as to allow the material to melt and have a greater HAZ area as well as the material thickness decreases so that it will affect the shear strength very significantly.

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Experimental study of the effect of adding incline prismatic triangle fin to the air flow under v-corrugated absorber plate for solar air heater efficiency

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AIP Conference Proceedings 2018年第1期1983卷

作者： Mohammad Hakam Djatmiko Ichsani Budi Utomo K. W. Wawan Aries W. Alifia Mashita 1Mechanical Engineering Department of Sepuluh Nopember Institute of Technology Surabaya - Indonesia 2Safety Engineering Study Program of Shipbuilding Polytechnic of Surabaya – Indonesia

Solar Air Collector is an apparatus that can be applied to convert solar radiation to be thermal energy. To increase the thermal efficiency of solar air collector, modification is needed by constructing the absorption area wider using v-corrugated plate absorber and adding prismatic triangle fin. Experimental sets to test the effect of fin addition to solar collector’s performance and efficiency. The experiment uses v-corrugated absorber plate and 30° bill shaped obstacle with fin addition. The geometry of the fins is prismatic triangle fin. Fin thickness of 3 mm, with 0.5L, spacing between the obstacle and fin angle to air flow 67.5°. Intensity of radiation are varied from 431; 575; 719 W/m2 respectively, and mass flow rate are varied from 0.002; 0.004; 0.006; 0.008 kg/s, respectively. The result of experimental study, the highest efficiency is 92.6% achieved by 0.008 kg/s mass flow rate and radiation intensity 431.372 W/m2.

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Aluminum Alloy Piston Fabrication Technology by Super Forging-KIRIU

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IOP Conference Series: Materials Science and engineering 2020年第1期924卷

作者： Lydia Anggraini Adelya Anjany Study Program of Mechanical Engineering President University Jl. Ki Hajar Dewantara Jababeka Education Park Cikarang Bekasi 17550 Indonesia

This research aims to produce pistons a lighter and stronger piston, even in high compression and high engine speed conditions. The piston fabrication process is carried out by super forging using Aluminum as a raw material with a compound choice by Silicon or Magnesium. In addition, the outer layer of the piston is covered by molybdenum with the coating process as nanotechnology to prevent corrosion. Furthermore, the finishing is controlled by the programming system machine named CNC (Computerized Numerical Control). In addition to CNC, the automation system is carried out by the KIRIU machine which is also used in this study. The results of this study show that the use of Al-Si alloy base material has better piston quality and able to withstand high compression or high engine speed. Then, the Al-Si superforging piston compared to the two final automation processes of CNC and KIRIU. The evaluation results have proved that the KIRIU machine provides high accuracy and the actual production increases by 20% compared to CNC.

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