bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proposing a More Efficient Maintenance Scheduling for an Overhaul Maintenance Project in Engineering Asset Management
Authors: Cahyo W N , Hasibuan F W , Hendradewa A P 
Published: January 2020

Abstract
In maintenance activity, scheduling planning is an important step to improve the performance of maintenance department. In some cases, the data to support the process to develop the maintenance schedule is unavailable. In this research, it is argued that Genetic Algorithm (GA) is an appropriate tool to support the decision maker in order to develop the schedule. The data required in this research is obtained from the maintenance data in the sugar milling company in Yogyakarta. The company run the production of sugar and spirits/alcohol. The Production process (milling seasin) is usually performed within the harvesting months of the raw material: the sugar cane. It is approximately in the month of February to August. On the other hand, the overhaul maintenance process is performed after the milling season. The overhaul maintenance planning is created by the manager of the maintenance department, and usually is done using the manager qualitative approach without any sciencetific approach. To get a more efficient schedule of maintenance, several parameters are set in this research. The parameters are then applied as the paramenters in GA. Those are: The number of manpower required and the duration of operation each activity. To run the GA model, Python programming is used. Before start the GA process, the parent chromosom and its fitness are determined. The date of maintenance activity start per each activity is set as the parent chromosome and the fitness is determined using a formula. The process of finding the better maintenance schedule is then performed based on the procedures in GA. It is indicated from the result that the proposed schedule generated in GA required less number of manpower.
An ergonomic, mobile and portable design of porang cutting and drying machine on motorcycle
Authors: Nurmianto E , Anzip A , Kusrini D E 
Published: January 2020

Abstract
This research is aimed to improve management of Porang (Amorphophallus Muelleri Blume, Indonesia Konjac), in Glucomannan Industrialization. The problem arises when they cut and dry manually on porang with very low productivity. Problems solved when there is a machine for cutting and drying porang on motorcycle which are Mobile, Portable and Ergonomic. This machine used to process with a higher production capacity. This porang processing innovation in the form of cutting and drying machine as well as processing porang into various preparations that combine several processing functions that are safe, comfortable, and healthy for its users and effective for their products. The conclusion is (1) from the data test of the machine it got 15 mm diameter of porang with maximum force of cutting machine is 22,1 kg, (2) Already build drying machine porang that can produce 1,061 kg/hours porang chips, (3) Based on the test and calculation, the porang’s cutting and drying machine can produce 190,89 kg/hours porang chips. Then if it observed from manual cutting that can only produce 65 kg/hours porang chips, so this machine can increase 3 times of productivity of the farmers. Finally, it is hoped that after using this machine, farmers will be prosperous.
Ni Metal Extraction with Surfactant Variation on Double Surfactant Emulsion Liquid Membrane Technology
Authors: Yuliusman  , Nafish A R , Salsabila C S , Ayu M P , Isa M 
Published: January 2020

Abstract
Nickel metal extraction from hydrotreating catalyst waste is an attempt to recover purer Ni metal using extraction process. Emulsion liquid membrane with double surfactant was chosen because this extraction method has the highest separation efficiency, shorter time of process, and simple process steps. The double surfactant that was varied in this study was a mixture of Span 80 with Tween 20 and Span 80 with Tween 80. The experimental results showed that the best nickel extraction was obtained using Cyanex 272 extract with a concentration of 0.06 M, 8% (w / v) surfactant double Span 80 with Tween 20, with an internal phase ratio and organic phase of 1: 1. The extraction process lasts for 15 minutes with a stirring speed of 250 rpm.
Proposed Reaction Mechanism of Chitosan-graft-Maleic from Chitosan and Maleic Anhydride
Authors: Timotius D , Kusumastuti Y , Putri N R E , Rochmadi  
Published: January 2020

Abstract
Chitosan (Ch), a natural polysaccharide derived from chitin is a widely used raw material in biomaterial research. Modification of chitosan using maleic anhydride (MA) have been done by several researchers with dimethyl sulfoxide (DMSO) and acetic acid as a common solvent. In the present work the chitosan was grafted with maleic anhydride using acetic acid and water as a solvent toward ecofriendly functionalization process. In addition, proposed mechanism of this grafting was further studied. The total acidic content and conversion of grafted films were calculated with varying concentration of MA:Ch ratio and temperature. The success of chitosan grafting with maleic was verified by Fourier Transform Infrared Spectroscopy (FTIR) analysis. FTIR analysis showed the appearance of new ester group and shifting of amide group from FTIR spectra which indicates that the esterification and amidation occurred in this grafting process.
Analysis of effectiveness of heat exchanger shell and tube type one shell two tube pass as cooling oil
Authors: Napitupulu Farel H. , Situmorang Romulus , Sihombing H V 
Published: January 2020

Abstract
Heat exchanger is a device that produces heat transfer from a fluid to another fluid, which can be applied as a cooling oil to maintain the oil temperature at the operating standard. This study was conducted to determine whether the oil temperature exit the shell and tube heat exchanger one shell and two tube pass, by calculating the effectiveness of the cooling oil on the tube (tube) using water as cooling fluid flowing through the shell (shell) using NTU-ε and experimental studies. Shell and tube heat exchanger one shell and two tubes pass effective used to cooling oil, because it can reduce oil temperature up to 32 %.
Design of microhidro turbine for electricity plants based on techno park in cimanggu village
Authors: Samosir Rahmad , Turnip Kimar , Simanjuntak Sutan LMH 
Published: January 2020

Abstract
The utilization of water as a natural resource of renewable energy for power plant is one of the alternative solutions to replace the need for fossil fuels. In Cimanggu village, there is a river that has a waterfall, which can be used to generate electricity. But the waterfall is currently used as a village tour. From observations and the calculation speed of the flow by using buoys, and river cross-sectional area obtained the total river debit Q more than 0.07 m3 / s. From the measurements is also obtained high fall the waterfall H = 22 m. Based on the existing height and debit of the water fall the major dimensions of a water turbine Pelton Micro Hydro type as the driving power generator was planned. The results of calculations for effective head = 18 m, with a water debit that is used to drive the runners Q = 0.07 m3/s, gained power generated by 7,0 kW. By the data is planned the main dimensions of micro turbine, Pelton outer runner diameter D = 250 mm, the diameter of the circle pin DL = 346 mm, number of blades z = 12 with 2 nozzles, and a shaft diameter ds = 30 mm. In planning this turbine, water is only directed to radiate to one side in order to replace the function of the waterfall. Because water is directed to one side, the shaft will experience an axial force (which is parallel to the shaft).
Study on the performance of the Otto engine by using mixtures of gasoline-bioethanol of nira
Authors: Sitorus T. B. , Siagian J. A. R. , Christopel B. 
Published: January 2020

Abstract
One of the alternative fuel that can be used for Otto engines is bioethanol. Bioethanol has a high octane number and higher oxygen content than gasoline and produced emissions are more environmentally friendly. This research to determine the Otto engine stationary four-stroke performance when using a gasoline-bioethanol mixture. The study was carried out with variations in the composition of the mix of bioethanol-gasoline, variations in engine speed and load engine. The experiment results show that the maximum thermal efficiency obtained is 29.63% when using gasoline at 1000 rpm and the load of 20 kg. The minimum SFC value is obtained 284.47 gr/kWh at 1000 rpm when using gasoline for the load of 20 kg. The SFC has increased when using a bioethanol-gasoline mixture. However, the exhaust emissions produced when the engine uses a mix of bioethanol-gasoline, it becomes more environmentally friendly.
Manufacturing and testing prototype of a gamma type Stirling engine for micro-CHP application
Authors: Jufrizal  , Napitupulu Farel H. , Ilmi  , Ambarita Himsar 
Published: January 2020

AbstractIn this study, a gamma type Stirling engine was produced and tested for the micro-CHP system with a swept volume of compression 106 cc. The engine is tested by air and uses LPG fuel as a heat source. Air pressure at the beginning of the compression process is considered to be the ideal gas pressure of 0.987 bar. The best working characteristics of the machine were obtained in the first test with a temperature difference on the hot and cold side of an average of 74.7°C. Maximum output and power output were obtained at 1.82 bar charge pressure of 242.6 rpm and 12.9 W. The results found were encouraging to begin the prototype gamma type Stirling engine for micro-CHP applications.
Experiemental study on solar dryer with extended flat plate collector
Authors: Qadry Al , Hutagalung Tommy , Harry Kevinta J.M , Napitupulu Richard A. M. , Ambarita Himsar 
Published: January 2020

Abstract
These study relates to coffee dryers sourced from solar energy, the main objective of these experiements are make solar drying tools more effective, save time, and get good quality coffee beans, so that they can be received by the community. The parameters that are used in this combustion are temperature, rh, sun intensity, weight, and Mr. the results obtained are that the temperature can vary between 40-60°C, with a maximum rh is 5%, weighing 4.291 kg, and finally getting the drying rate. The main conclusion are these temperatures are very suitable for drying coffee beans, the higher the intensity of solar radiation will reduce the drying Moisture ratio and can be reduce of mass coffee.
Design tools multifunction equipment
Authors: Siregar Ikhsan 
Published: January 2020

Abstract
Product design can be defined as idea generation, concept development, testing and implementation of manufacturing (physical objects) or services. Product designers create concepts and evaluate ideas, making ideas come true through products in a more systematic approach. The purpose of this research is to help farmers who are engaged in SMEs chips. Tool attributes are derived from results brainstorming by tool designers. Design size data is obtained from direct observation and survey market of sliced chips on the market and according to consumer tastes. This versatile slicer is used to increase the production of farmers. The data obtained for the specification of the tool is data from the results of answers on questionnaires distributed directly to entrepreneurs SMEs chips residing in some areas, Medan Tuntungan, Medan, Indonesia. Brainstorming is a method used to generate a large number of ideas that most of these ideas will be discarded. With QFD method, compared multifunction slicing tool with 3 other competitors with the same attribute. Sub solutions are generated from the completion of any emerging issues, including in selecting attributes for bird repellents using measures Nigel Cross to maintain excellence and improve product quality. From an alternative generation with a combination of attributes, the result is an alternative 1 as the basic criterion in making an orange-drawer. Evaluate alternatives using Pairwise Comparison and scales AHP to calculate the weighting of each attribute and determine the ranking of each alternative. Value engineering is the final step in the design process with the aim of increasing the value of the product to the consumer and lowering the costs that must be incurred by the manufacturer
Using filtration as a technology to remove pollutants in domestic wastewater
Authors: Utari Andiny Widya , Herdiansyah Herdis 
Published: January 2020

Abstract
Most of the wastewater produced comes from household activities. Household wastewater currently tends to be directly disposed into water bodies without prior treatment. As a result, the concentration of pollutants, especially TSS and COD in the waters became high. It is necessary to manage household wastewater, so that the disposed waste is still within safe limits that do not pollute the environment. Filtration is one of treatment methods which is generally used in the processing of clean water, but the materials used in the filtration process also have the ability to reduce pollutant levels in wastewater. This study aims to find out that filtration can be used as a method of household wastewater treatment. The method in this study is to conduct a trial using a simple filtration method to analyse the decrease in household waste levels. The result shows that the percentage of TSS and COD removal are 79.01% and 77.84%. The conclusion in this study is that filtration can be used as a method of household wastewater treatment because the material used can reduce the concentration of TSS and COD to below the specified quality standard.
Air temperature analysis in Kalijodo green open space (study in penjaringan, North Jakarta)
Authors: Pardamean Mbarep Daniel Putra , Herdiansyah Herdis 
Published: January 2020

Abstract
Green open space is a public space created with the aim of carrying out one of the ecological functions as a climate regulator to create an air temperature that matches thermal comfort. Regarding the function of Kalijodo’s green open space in regulating microclimate, a study was conducted to measure air temperature using Thermo-hygrometer in 5 (five) monitoring location points (TP1, TP2, TP3, TP4, TP5) at different times. The measurement results show that the air temperature in the green open space of Kalijodo has a mean value of 33.22°C and exceeds the specified threshold (20.5-27.1°C). This is influenced by the physical conditions of the environment such as damaged and arid soil conditions and vegetation density. So that it is necessary to arrange green open space in accordance with applicable provisions so that functions in green open space can run ideally and sustainably.
Review on community-based strategies for improving the quality of lake waters (Case study: Urban Lake Rawa Besar, Depok, West Java, Indonesia)
Authors: Saragi Putri Andreyna , Budhi Soesilo Tri Edhi , Abidin Chairil Abdini 
Published: January 2020

Abstract
Lakes provide important habitat for fish, birds, reptiles and aquatic plants, and produce fishing, tourism and recreation industries. However, the condition of the lake’s water quality continues to decline. Until now, lake management has not reflected sustainable lake management. This paper aims to provide a review of community-based water quality improvement strategies. The case study is in urban lake Rawa Besar, Depok, West Java, Indonesia. This paper not only provides a strategy but before that there is a comprehensive analysis of the factors causing a decline in the quality of lake waters, so that the strategy is expected to be appropriate. The community is also expected to be the main and first protector of the condition of the quality of the lake waters.
Sustainability assessment in construction industry supply network: a review
Authors: Sitepu Muhammad Haikal , Matondang Abdul Rahim , Tryana Meilita 
Published: January 2020

Abstract
Construction industry plays important role to support human welfare by providing access for living and moving. Developed countries are characterized by having good infrastructures such as roads, bridges, office towers, residential buildings, seaports and airports. To have these infrastructures, massive construction projects must be implemented by construction industry. This industry consists of several activities such as extracting raw materials, manufacturing construction’s materials, construction projects, infrastructure operational, and after operational activities that are run by different organizations and companies. These organizations and companies configure construction industry supply networks. Despite of the positive impact of these supply networks in improving human and product mobility, these supply networks also responsible for significant negative impacts such as consuming high energy and material resources, producing greenhouse gas emission and creating waste. To monitor and maintain these negative impacts, a sustainability assessment process is required. This paper aims to review sustainability assessment process in construction industry supply networks. It was found that different indicators are required for assessing activities in each stage of supply networks.
Analysis of mechanical and physical behaviour of post-burn concrete
Authors: Karolina Rahmi , Yulia Corsika M. S 
Published: January 2020

Abstract
The occurrence of a high temperature change, such as in a fire incident will have an impact on the concrete structure, cracked surface structure, damage/collapse, and discoloration of the concrete. This research is conducted on K300 concrete with a sample of 15 cm x 15 cm x 15 cm cubes. Burning is carried out at temperatures of 250°C, 500°C, 750°C, and 1000°C with a containment time of 2, 4 and 6 hours. The cooling process is carried out by immersion then rested for 24 hours at room temperature. From the results of the research obtained at temperatures of 250°C, 500°C, 750°C, and 1000°C, the decrease in compressive strength are 4.44% -7.41%, 12.59% -22.96%, 56.44% -66.22%, and 76.74% - 100%. At the containment time for 2 hours, 4 hours and 6 hours, the decrease in compressive strength are w = 4.44% - 76.74%, 6.67% -93.70%, and 7.41% - 100%. At temperatures of 250 °C, 500°C, 750°C, and 1000°C, the increase in porosity are 8.09% - 9.57%, 11.79% - 15.50%, 16.98% - 18.46%, and 19.20% - 26.61%. At the containment time for 2 hours, 4 hours, and 6 hours, the increase in porosity are 8.09% - 19.20%, 8.83% - 22.16%, and 9.57% - 26.61%. From this research, it can be seen that the increase in temperature has a greater impact on the decrease in the compressive strength of concrete and the increase in the porosity of concrete compared to the increase in the combustion duration. Through this research, regression equations are generated which can be used to calculate the residual compressive strength at other combustion temperatures.
Analysis of quenching heat treatment, martemper on structure micro and hardness in SCMn3 steel.
Authors: Max Sesmaro Yuda 
Published: January 2020

Abstract
Microstructure analysis and hardness analysis has been carried out on cast steel for components of soil digging machines due to heat treatment of quench, and martemper. The presence of residual austenite causes wear resistance and reduced fracture strength in the earth quarry component to function as a support for the designed arm. In its manufacture, it uses metal casting technology and heat quenching treatments and templates in suitable cooling media, to meet standard requirements. The temperature treatment of austenite 875 °C temperature was held for 90 minutes, and then quenched with variations in the cooling media of water, oil, and salt bath. Furthermore, the martemper process at 425 °C for 90 minutes is cooled to air to room temperature. Microstructure testing and weight percent composition using SEM-EDX and Brihnell scale hardness test. The analysis shows that the hardness value (388 HB) of cast steel quenched in salt bath media is greater than ordinary water (299 HB) and oil (260 HB). However, after the martemper process the value of hardness drops to (342 HB) in the salt water medium, which remains larger than ordinary water (264 HB) and oil (233 HB). This is due to the faster cooling speed in brine and produces martensitic microstructure and residual austenite after being observed with SEM-EDX. The results of this study meet the quality requirements according to the JIS G5111 standard where the minimum hardness value is 222 HB, to be used as a component in excavator.
Analyze the proportion of volcanic ash of Sinabung volcano at the most optimum to get the compressive strength and tensile strength of concrete
Authors: Sebayang Melya Dyanasari 
Published: January 2020

Abstract
The development of concrete as construction material is growing very rapidly followed by the needs of diverse communities. Based on the problems, we need knowledge and inovation to get a good quality concrete with low cost. In this study, volcanic ash of Mount Sinabung was chosen as an alternative material plus concrete filler. Materials derived from the bowels of the earth will be tested optimum levels that can be used to achieve the compressive strength and maximum tensile strength. The concrete to be tested is a concrete mixture design with fc ′249 kg / cm2 (K-300). The concrete mix design was done by reducing the use of cement and the addition of volcanic ash of Mount Sinabung (0%, 10%, 15%, 20%). Compressive strength is tested when it’s 7, 14, and 28 days old. But, ultimate tensile strength is tested when it’s 28 days old. From the test result, we get optimum percentage with volcanic ash from Mount Sinabung is 10% with compressive strength 19.689 Mpa and ultimate tensile strength 1.348 Mpa. However, material is still worthy to use as concrete because it is compressive and ultimate tensile strength that almost reach normal compressive and ultimate tensile strength. Moreover, the using of material as admixture for concrete can be used as an alternative to save the environment from pollution.
Estimating the opportunities of ester content improvement through variation of NaOH, KI And KIO3 developed impregnators on activated natural zeolite catalyst for methyl ester synthesis
Authors: Kurniasih E , Pardi P 
Published: January 2020

Abstract
The Content of esters are the number of compositions of esters formed after the esterification and / or when transesterification reaction takes place. Esters are formed by breaking up the alkyl acid carboxylic group of fatty acids or triglycerides which react with methyl groups from methanol. To increase the reaction rate, heterogeneous catalysts were synthesized using impregnators NaOH, KI and KIO3. The impregnator is carried out in the framework of natural zeolite with a concentration of 2.5% (w/v). The zeolite framework was previously activated using 6M HCl solution for 10 hours at a temperature of 90°C. To strengthen the impregnator bond on a heterogeneous zeolite catalyst, calcination was carried out at a temperature of 600°C for 4 hours. Heterogeneous catalysts were tested on biodiesel production using a transesterification reaction. The transesterification reaction was carried out at a temperature of 65°C for 2 hours based on crude ester with 5%-10% (w/w) heterogeneous zeolite catalyst ratio shows the percentage decrease in free fatty acid content of 74.05% for zeolite/NaOH, 75.01% for zeolite/KIO3 and 75.77% for zeolite/KI. Based on the results of gas chromatography analysis, it was found that zeolite/KI catalysts of 77.1591.86%.