bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of paratransit performance as public transport in Medan City
Authors: Anas Ridwan , Kholis Hasibuan Ami , Bayu Endrayana Dharmowijoyo Dimas , Sembiring Irwan S. , Ariessa Dewi Rezky
Published: June 2020

Although bus comfort is a crucial indicator of service quality, existing studies tend to focus on passenger load factor and headway. This study examines the performance of paratransit in Medan city by using those criteria. The analysis is conducted using survey passengers onboard expressed as a percent of available seats and number of fleets required to operate a transport route for a given interval. The result showed there is significant gap in paratransit load factor from government regulation, and average headways of paratransit still fulfilling the level of services except for 2 operators which is National and Mars. Government intervention is needed to increase the service’s reliability of public transport.
Effect of compaction and direct shear test values on peat soil of Batubara Regency, Sumatera Utara Province
Authors: Roesyanto  , Rizki Eka Putri Vini
Published: June 2020

Peat soil is an organic soil and is usually found in low-lying areas where the water table is near the ground surface. The peat Soil has very large water reserves, high compression and has a low carrying capacity. This study aims to ascertain the index properties, to classify the peat soil classification according to ASTM 4427-92 (2002), to get the optimum water content and maximum dry unit weight by Standard Proctor test, and to analyze the shear strength of peat soil by direct shear test. The peat soil had water content (w) of 752.833 % and specific gravity (Gs) of 1.533. According to ASTM 4427-92 (2002), the peat soil was classified as high-ash peat with more than 15 % ash and as slightly acidic peat with a pH between 4.5 and 6.5. From the Standard Proctor test, the peat soil had an optimum water content of 37.235 % and 0.474 gr/cm3 maximum dry unit weight (γdmax). The Standard Proctor test increased the value of the dry unit weight (γd) of 0.169 gr/cm3 to 0.519 gr/cm3. The original internal friction angles (φ) and cohesion (c) were 0.885º and 0.015 MPa respectively while the Standard Proctor test resulted in 5.294º of internal friction angle (φ) and 0.023 MPa of cohesion (c).
Study of CBR (California Bearing Ratio) value on peat soil of Asahan Regency Sumatera Utara Province
Authors: Roesyanto  , Lestari T P
Published: June 2020

Peat soil is a type of soil within condition dominated by the litter of remaining plants which dead and rotten by nature so enrich with organic structure and water content in high concentration. This type of soil usually found in saturated water areas like swamp and basin. Called peat soil if organic structure content inside soil more than 30%, but swamp forests in Indonesia usually have more than 65% and more than 50cm depth. This research goal was to know the physical character (index properties) from peat soil and also the classification, to know the CBR (California Bearing Ratio) value of laboratory test and to know the CBR value after soaking the samples for 3 days. From this research it was found that peat soil from Pertanahan village, Sub-district Sei Kepayang Asahan Regency had 518.090% water content, 1.302 specific gravity, 3.672 void ratio, 0.454gr/cm3 moist unit weight, 0.098gr/cm3 dry unit weight, 45.032% ash content, 54.968% organic content, and it was classified as High Ash Peat. The peat soil had acidity pH of 4 and it was classified as Highly Acidic Peat with a pH less than 4.5. The CBR unsoaked value of peat soil was 6.750 % and the CBR soaked in three days was 2.800%.
Study on displacement and strain of concrete cubes using digital image correlation (DIC)
Authors: Putri Wijanarko Nadia , Arijoeni Essy , Okto Bangkit Sentosa Bastian
Published: June 2020

Digital Image Correlation (DIC) is a new, cutting edge technology employed the study full-field displacement of materials; concrete included. DIC uses the help of digital images that was recorded sequentially during testing period. There had never been a research conducted using the method in Universitas Indonesia using conventional tools. This research proves that such thing is possible. The component and steps to DIC are extensively discussed in the research; speckle pattern, method of record, images produced, and data computation. Through this research, the behavior of how displacement and strain were developed when concrete is subjected to compressive testing can be studied. The results of the research were analyzed quantitatively using the digital images and its computation based on computer software used. Additionally, provided that this was a preliminary research, there are many aspects and suggestions found from this research that will be applicable for future researches.
Integrated systems of major drainage and minor drainage towards low impact development
Authors: Siregar R I , Nursyamsi N , Indrawan I , Sembiring R A , Karolina R , Dewi R A
Published: June 2020

Many studies have been conducting in providing urban floods solutions to reduce runoff water in various ways. In developing urban areas equipped with drainage systems, where the channel has full capacity and flooding in some urban areas. One of the problems that can be identified is the condition where drainage has a peak flow load at the same hour leading to the same meeting point, outlet, or discharge, resulting in an increase of peak flow. This paper give an approach to how to integrate the runoff capacity of flow from minor drainage to mayor drainage for anticipating a peak flow in a particular area. The most important result was when high rainfall intensity started in the first hour, it should be no obstacles until the flow from minor drainage flow through the outlet towards major drainage, in the four hours after rainfall, peak flow happens to flow through study area. In the analysis, it is known that the peak flood discharge period of 5-yr and 10-yr returns is one hour after the rainfall. Therefore this will not happen when the flow from the drainage outlet has a travel time of under one hour or after 3 hours after rainfall.
Numerical study of damage index of 2d steel building with eccentrically braced frame using OPENSEES
Authors: Jonathan Victor , Orientilize Mulia , Okto Bangkit Sentosa Bastian
Published: June 2020

Measuring degree of damage of structure under an earthquake has been researched by numerous researchers since it is difficult to ensure whether the designed building structure could withstand. In earlier research, structural damage detection method used natural frequency to indicate damage. However, this method is not spatially specific, nor are they sensitive to damage. Thus, damage index is introduced as a tool to measure the damage in specific scale of zero to one. Among different types of damage index, Park-Ang damage index is used. Model of building structure that will be analysed is steel building with Eccentrically braced frame system. EBF system has extraordinary characteristics which has high ductility of dissipating energy and also sufficient stiffness to prevent from buckling. 2D model of EBF building with variation of number of story (one, three and five story) is identified regarding to behaviour, damage index and natural frequency. The behaviour of EBF building is identified by observing the monotonic and semi-cyclic pushover analysis. Damage index of EBF building structure is identified using OpenSees program. Furthermore, natural frequency that also measure degree of damage is identified using SAP2000. By determining damage index and natural frequency, the correlation between two can be observed.
Shear behavior of interlocking masonry brick wall portal with the substitution of Mount Sinabung volcanic ash against pushover static load
Authors: Karolina R , Syahrizal  , Handana M A P , Ramadhan P
Published: June 2020

Earthquake events produce a shear damage effect on the interlocking masonry wall brick in the form of diagonal cracks. This shows that there’s an influence of the resistance of the masonry to bear the shear force against the horizontal force in the direction of the wall plane caused by the earthquake. The purpose of this research is to determine the shear strength and crack patterns of walls against static loads and to utilize volcanic ash from Mount Sinabung as one of the constituent materials of interlocking masonry brick because the eruption activity of Mount Sinabung is also one of the most active in the world. The samples are in the form of a 3 m x 3 m wall surrounded by a 0.13 m x 0.13 m beam-column portal filled with interlocking masonry brick of 0.25 m x 0.125 m x 0.1 m with the optimum substitution of Mount Sinabung volcanic ash by 20% as a substitute for sand. Wall portal test was done by giving a pushover static load on the wall joint which refers to ASTM E 564-2003 to get the value of shear strength and crack pattern of the wall. From the static test results of interlocking masonry brick wall portal, the samples are able to accept a pushover load of 63931.2 N which results in an ultimate displacement of 35 mm with a crack thickness of 4 mm. The wall shear strength obtained is 21.31 N / mm. Based on the analysis of the equivalent energy elastic plastic (EEEP) curve, it is obtained that the elastic stiffness of the wall is 5905.88 N / mm and the wall’s yield load is 57237.55 N with the deviation of 9.69 mm. Failure of the interlocking masonry brick wall portal is a shear failure characterized by cracking like a ladder pattern on the wall. Based on the crack pattern that occurs, the wall portal is a type of stepped cracks shear failure.
Comparison of road inequality values using roughometer III and roadroid applications
Authors: Surbakti Medis S , Ginting Puja
Published: June 2020

Roads are essential in the development of an area, where driving safety and comfort are a measure of road construction. We can check road construction by getting an IRI value on a road segment. IRI (International Roughness Index) is the roughness index that most commonly obtained from measured longitudinal road profiles. Roughometer III and Roadroid applications are the tolls to collect IRI data. Roughometer III has more precision than Roadroid, but the Roughometer III is more expensive and more complex than Roadroid. This study tries to make a comparison of IRI values and their correlation between the Roughometer III and Roadroid. The results show that the comparison of IRI Roughometer III values and Roadroid Applications is slightly different. The linear correlation analysis of IRI values on Roughometer III and eIRI values on Roadroid is IRI = 0.8999eIRI + 0.5786 with a correlation level of = 0.8391.
Green campus concept based on architect perspective
Authors: Tamiami Fachrudin Hilma
Published: June 2020

The green concept is a part of a sustainable concept. The application of the green concept to buildings is an important thing to be realized. At this time, the university is trying to apply the green concept to the building and its environment. The application of green concepts on campus requires a large investment but many benefits can be obtained such as low maintenance costs and good environmental quality. This research aims to develop a green concept that can be applied to the campus based on architect perspective. The method used is qualitative with the technique of data collection is interviews with ten architects who have participated in green assistance organized by the Green Building Council Indonesia. The data obtained were analysed descriptively. The results of the study showed that the architect agreed on the application of green concepts to the campus both in the building and its environment. Some green concept indicators that should be applied are building, water conservation, landscape, energy conservation, transportation, waste management and education. The green campus can be realized if it is supported by the vision, mission, and regulations by the rector and gets support from students and staff in its implementation.
Design of heat exchanger (evaporator) type of staggered tube cross-flow as modified evaporator AC-split
Authors: Napitupulu F. H. , Fellix  , Sihombing H.V.
Published: June 2020

This study aims to make a tube group type evaporator design alternately with crossing flow as a result of modification of split PK 1 evaporator AC and to evaporate the working fluid, namely R-22, to environmental so that it also simultaneously cools the room. The evaporator designed has a length of 26 cm, a width of 16 cm and a height of 84.2 cm, with a tube diameter of 6.35 mm, a tube length of 58 cm and as many as 25 passes, consisting of 5 rows and 5 columns with alternating positions, distance between tubes 15 mm vertically and horizontally. With this design, the evaporator can absorb heat duty from the room of 813 W.
Effect of choline hydroxide catalyst in the production of methyl ester from crude palm oil
Authors: Manurung R. , Syabri D. K. , Bestari N. G. , Anggreawan M. D. , Risnaidi  , Siregar A. G.
Published: June 2020

Ionic liquids as catalysts are very potentials for transesterification reactions for biodiesel synthesis. Choline hydroxide (ChOH) has a better catalytic reaction than other ionic liquids because during the reaction takes a shorter reaction time and only requires a small dose of catalyst, the conditions required to produce biodiesel with very high yields. Determination of the optimum conditions for methyl esters resulting from the transesterification reaction of crude palm oil (CPO) using response surface methodology (RSM). The experimental design used three variables, the use of catalyst dose, the molar ratio of crude palm oil (CPO) to methanol and reaction time. Optimal conditions showed the highest methyl ester content was 99.45% at 60 ° C, the molar ratio of methanol: CPO 12: 1 and catalyst dose of 3% and a time of 60 minutes. The final product met the selected biodiesel fuel properties by European Standard (EN) 14214. ChOH showed high potential to be used as a low-cost, easy to prepare and high-performance catalyst for biodiesel synthesis.
Effect of sulphuric acid (H2SO4) and sodium hydroxide (NaOH) addition to prevent silica scaling in geothermal power plant projection pipes at PLTP X
Authors: Trisakti B , Sidabutar R , Lumbangaol A K , Lumbangaol A K , Hutagalung A , Lumbangaol P , Irvan
Published: June 2020

Geothermal energy is energy stored in the form of water or steam in certain geological conditions at a depth of several kilometers in the earth’s crust. Power plants utilize geothermal combined cycle units that are more efficient than conventional types of geothermal power plants. PLTP X has 3 steam turbines with a pressure of 20 bar as the main generator drive and 18 steam tubs with a pressure of 10 bar. The process of Integrated Geothermal Power Plant is divided into two plants, namely dry steam power plant and binary cycle power plant. Heating working fluid in the binary cycle power plant itself uses condensate and brine water. One of problems in this PLTP X is the presence of silica scaling in production pipe and the increase of acid pH value in some production well which causes corrosion in production pipe. Therefore it is necessary to modify pH. The addition of sulfuric acid (H2SO4) and sodium hydroxide (NaOH) is needed to slow down the rate of silica deposition and to prevent corrosion of pipe.
Optimization and design of energy monitoring system in fuels terminal: a case study in North Sumatera province of Indonesia
Authors: Yurisman Edy , Bin Nur Taufiq , Ambarita Himsar , Putra Simanjuntak Adi , Sitorus Asril
Published: June 2020

Optimization of energy use in the PERTAMINA’s fuel terminal (TBBM) was carried out by the Energy Audit method. The data obtained during energy audit activities then processed to carry out the Energy Performance Indicators (EnPis) which produces Specific Energy Consumption (SEC) and energy baselines. The energy cost center that creates a web-based energy monitoring system is carried out to facilitate monitoring and control and will become supporting tools. The information provided from the energy monitoring system displays the profile of total energy consumption, distribution of energy consumption, the energy consumption of equipment in production facilities in the form of daily, monthly, and annual data. Energy intensity and baseline values obtained from energy consumption and production data for the past several years will be the target and warning system to maintain energy usage that exceeds reasonable limits. The results obtained by the value of energy intensity of 0.0023 GJ / KL, while the total emissions generated from energy consumption amounted to 1,144.4 tons-CO2 / year. 51% of energy is used for production facilities and the rest is used for supporting facilities. The use of electricity as well as thermal energy does not have a strong correlation with the level of fuel sales throughout the year and the use of NGS (New Gantry System) technology does not show a significant decrease in energy intensity, where IKE values fluctuate throughout the year. This reinforces the need for continuous and real time energy monitoring. By implementing the potential for energy savings, an energy use optimization is obtained by reducing energy consumption by an average of 10% - 15% per month or as much as 18,057 - 27,086 kWh per month, equivalent to 25 - 38 million rupiah per month.
Experimental of collector box solar water heaters using finned pipes as water flow
Authors: Ambarita H , Siahaan Firman W , Herdy
Published: June 2020

Solar energy is a renewable energy where heat obtained from the sun can be utilized without damaging the environment. The most common use of solar energy is to heat water both the active system and the thermosifon system. Using photovoltaic cells as an energy source to pump water is a promising breakthrough. This study aims to improve the efficiency of flat plate collectors with a size of 1.62m x 1.14m x 0.08m to heat water with a capacity of 120 L by adding finned pipes as continuous water circulation. After the collector finishes in the design, it isi being tested and analyzed in order to obtain the efficiency and total value of calorific waste of collector.
Experimental and numerical simulation of two 20° angled solar collectors with trapezoidal groove plate
Authors: Sirait Adolf Ronny H , Hutapea Gery P , Ambarita Himsar
Published: June 2020

Experimental and numerical study of two 20 ° angled solar collectors. The solar collector is operated in the 4th floor of the Mechanical Engineering Masters Building, University of North Sumatra, with the working principle that the radiation entering the solar collector will heat the absorber plate further with the help of the natural convection optimum air temperature on the absorber plate will make the temperature the collector’s room goes up. Data obtained from experimental measurements are then analyzed or validated using CFD software. The assumptions used in CFD simulations include: steady, incompressible conditions, k-epsilon flow, and models made in the form of 3-D, as well as giving boundary conditions to the object to be analyzed. The purpose of this numerical study is to analyze and study: temperature distribution and fluid flow numerically on the surface of the absorber plate. Based on the simulation results, conclusions are drawn both on temperature distribution and fluid flow according to the recording of results at the time of measurement.
Study of recycle spent brick lining as refractory castable product
Authors: Yudiarto Kukuh , Saleh Taufik , Rahadian Ferdy , Ashad Firman
Published: June 2020

Every year INALUM has produced around 500-1000 ton spent brick lining which placed in the dump yard. After it has been placed, it sells to the third party. Spent Brick lining which has been cleaned has no or little harmful content and some chemical composition can be utilized as a new product as the refractory application in INALUM. Some research proves that spent brick has some good mechanical properties if applicated as concrete and INALUM’s spent brick production high enough to fulfill castable needs in INALUM in a year. The General flow process of castable making is sorting and drying, crushing and grinding, screening, mixing (with other aggregate and additive). With this general production, its predicted to produce earnings after taxes (EAT) around IDR 678.232.000 per year.
Essential oil extraction from citronella grass by microwave-assisted hydro-distillation technique: a preliminary study
Authors: Sarah M , Estherina D
Published: June 2020

This study evaluates potency of microwave hydro-distillation method to yield citronella oil from citronella grass. The presence of microwave energy provides sufficient thermal heat to accelerate extraction process. Penetration of microwave energy into citronella grass sample facilitates temperature increment inside-out from the sample which enhance citronella oil released from cell wall immediately. Parameters to be evaluated in this study are temperature profile during extraction process and citronella oil yield. The variables observed in this study were power (300 Watt,450 Watt and 600 Watt) and time (30 minutes, 45 minutes and 60 minutes). This study observed the effect of power and time to the yield of essential oils. In this study, it was observed that the highest yield obtained during extraction using power of 600 Watt for about 60 minutes that yielded 9.7% citronella oil. The results indicate potency of microwaves as a heating medium for extracting essential oils as an effective method with respect to their efficient time feature.
Application of converting HSD to LNG
Authors: Husnuari Muhammad
Published: June 2020

Anode baking furnace uses oil as fuel. The baking process is decisive for the quality and cost of an anode, and the environmental impact. Using natural gas as fuel can reduce the cost production of the anode by $ 9.45, and reduce emission from combustion in the furnace for CO2 by 28%, NOx by 79 %, and SOx by more than 95 %. Emission reduction correlated to the consumption of NaOH that used for wastewater. NaOH can save by $ 34,000 per year and make more durability of the equipment. The total profit for this improvement is $ 1,245,345 per year.
Triacetin production using SiO2-H3PO4 catalysts derived from bamboo leaf biomass waste for esterification reactions of glycerol and acetic acid
Authors: Manurung Renita , Dedi Anggreawan Muhammad , Gery Siregar Alwi
Published: June 2020

Increasing the demand for renewable fuels especially for biodiesel has the effect of increasing by products during biodiesel production. Therefore, the efforts made to make biodiesel by products in the form of glycerol become more economic value, then further processing is carried out into biofuel additives. One of the biofuel additives that can be synthesized from glycerol is triacetin. In this study, the production of triacetin compounds was carried out through an esterification reaction using calcined SiO2-H3PO4 catalyst originating from bamboo leaf biomass waste so that glycerol conversion, concentration and selectivity of the best triacetin products from various reaction variables were obtained. The esterification process is carried out by reacting glycerol and acetic acid with a mass ratio of glycerol: acetic acid which is 1 : 9 at a temperature of 100 ± 5°C to produce the main product triacetin. The influence of various process variables such as catalyst type, catalyst weight, and reaction time on glycerol conversion was observed in this study. The best conditions produced in this study were the highest conversion of 100% glycerol, the concentration of triacetin products 18.53%, and selectivity of triacetin products 22.84% with catalyst type SiO2-H3PO4 1 : 2 (M/M), catalyst weight 5% from glycerol weight, reaction time of 4 hours, and stirring speed of 300 rpm.
Extraction of tannin from garlic skins by using microwave with ethanol as solvent
Authors: Pardede C. , Iriany  , Tambun R , Fitri M D , Husna R
Published: June 2020

Tannins are phenolic compounds which have benefits as an anti-oxidant, anti-diarrhea, anti-bacterial and astringent. This study aims to determine the tannin content and antioxidant activity of garlic skins by microwave assisted extraction method. In this research, ethanol is used as solvent and the various experimental consist of 1:6 g/ml, 1:8 g/ml and 1:10 g/ml of garlic skin (solid) to ethanol (liquid) ratio; 30 s, 60 s, 120 s, 180 s and 240 s of extraction time; and 100 W and 180 W of microwave power. The tannin content of garlic skins is determined with Folin-Ciocalteu method. The antioxidant activity of garlic skins is evaluated with DPPH method. The results showed that extraction conditions had significant effect on the extraction content of tannin compounds, and the optimum condition is found at solid to liquid ratio of 1:8; extraction time of 180 s and microwave power of 100 W. Tannin content under this condition is about 1.77% and the antioxidant activity index of garlic skin extract is 1.994. The results showed that microwave-assisted extraction method is suitable and effective to extract tannin from garlic skin.
Evaluation study of electrical energy usage using prayer models on post payment for electric customers household
Authors: Setiono I , Sasmoko P , Heru W
Published: June 2020

This study aims to find solutions for saving electricity consumption in households. This electricity consumption savings need to be done because it is seen from the supply side management, the availability and limitations of natural resources, especially for fossil materials that are widely used in power plants, are decreasing in number, not to mention the issue of potential CO2 emissions polluting the environment due to activities at this power station. Whereas seen from the demand side management, the savings in electricity consumption will reduce electricity expenditure for the consumer community, especially household customers. The method of research is carried out with a survey in the field. Respondents were divided into two groups, namely the experimental group from prepaid electricity customers and control groups from postpaid electricity customers. By applying the same load to the control group with the experimental group, then the level of accuracy is measured. Samples taken randomly. From the data generated in the analysis of whether there are significant differences in the experimental group can bring changes in electricity consumption in the control group. Furthermore, from the results of data analysis can be used to draw conclusions. This is where there will be benefits to be gained, namely a new concept of how to use electricity that is economical. and this concept is ready to be implemented in the community, through a community service program, which is certainly very useful for stakeholders and published through international seminars and made as a supplementary textbook for electrical power installation courses.
Improving the utilization of palm oil mill through fulfillment of fresh fruit bunch
Authors: Masril Muntashir , Nazaruddin  , Hidayati Juliza
Published: June 2020

Asahan District consists of Sei Dadap Estate, Bandar Selamat Estate, Sei Silau Estate, Pulau Mandi Estate, Ambalutu Estate, Hutapadang Estate, and Sei Silau Palm Oil Mill. Asahan District has a factory capacity of 50 tons of FFB per hour. The analysis was carried out using the Food Supply Chain Networking (FSCN) method. The FSCN method is carried out by discussing six aspects of the supply chain in the form of supply chain objectives, supply chain structure, supply resources, chain management, chain business processes, and supply chain performance. This study aims to design the fulfillment of FFB supply needs at PTPN III in the district of asahan with a factory installed capacity of 50 tons of FFB per hour based on the projected calculation of the availability of FFB from the supplier’s farm. The number of FFB available based on the calculation of production results for the next five years for 2019-2023 is 337,156 tons, 328,885 tons, 323,296 tons, 311,253 tons and 300,401 tons. Based on the target if as much as 92% of factory utilities, plantation production will decrease by around 3% per year, in the third to the fifth year of Sei Silau POM will experience a shortage of FFB supply, so an additional third party is needed. the composition of the mature plant is not balanced, namely in juvenile palm by 35% whereas for young palm FFB production will increase by 13%, FFB production will decrease in adolescents by 42% and for the palm of old age will start in Replanting by 9%.
Quality improvement of liquid smoke from oil palm frond pyrolysis through the adsorption-distillation process using activated carbon as adsorbent
Authors: Maulina S , Amalia R
Published: June 2020

This study aims to produce and analyze the quality of purified liquid smoke through the adsorption process with activated carbon and distillation. In this study, liquid smoke was produced from the pyrolysis of oil palm fronds with operating conditions of temperatures of 400°C, 500°C, and 600°C for 40 minutes, 90 minutes, and 120 minutes. Liquid smoke was adsorbed using activated carbon and distilled at 150°C for 45 minutes. The characteristics of liquid smoke were analyzed using GC-MS instrument. The parameters observed were phenolic, acids, and carbonyl compounds. The results showed that acid compounds were the most dominant component in liquid smoke obtained. After purification, the color of liquid smoke turned bright yellow and the pungent smell of smoke from liquid smoke decreased.
Analysis of effect of leadership style, work motivation and work ability to employee satisfaction in increasing performance of harvesters
Authors: Pinayungan Dongoran Ahmad , Nazaruddin  , Purnomo Wibowo Rulianda
Published: June 2020

The purpose of research was to analyze the effect of leadership style, motivation and ability on work satisfaction in improving harvesting performance of harvesters in Bukit Sentang, Padang Mandarsah, Dalu-dalu and Dawas plantation of Indonesia Oil Palm Research Institute (IOPRI). the analytical method used in this research is the analysis of correlation and linear regression with path analiysis. The results of the research showed that simultaneous leadership style, work motivation and work ability had an effect on job satisfaction, as well as leadership style, work ability and job satisfaction had an effect on job performance. Partially, leadership style and work ability have a significant positive effect, but work motivation does not have a significant effect on job satisfaction. While work ability has a significant positive effect, but leadership style and job satisfaction have no significant effect on job performance. The percentage of direct effect of leadership style was 33.41% on job satisfaction, while work ability was only 6.81% and work motivation was 1.44%. The percentage of direct effect of work ability is 17.56% on work performance, while the leadership style is 1.90% and work ability is 1.23%.
Rubber fruit shell: agricultural waste material as a potential sustainable production for wastewater treatment
Authors: Naswir Muhammad , Yasdi  , Rahima Siti , Gusti Wibowo Yudha
Published: June 2020

Water quality is a problem in recent decades, rubber fruit shell in agricultural waste will be a solution to solve wastewater treatment. Rubber fruit shell has dried by sunshine for three days and crushed using crusher until the material becomes ash, ash has sifted in 80 and 120 mesh. Ash burned in 400°C and 500°C, ash has activated use acid activator (H3PO4) 10% for 24 hours, and then carbon cleaned by aquadest till the pH is seven. Then, carbon has dried in oven for 3 hours with temperature 110°C. Specification test using gravimetric method has used to find water concentration and ash content in rubber fruit shell. Titration test used to find adsorption of iodine (mg/g), spectrophotometry UV-VIS used to find adsorption of blue methylene with a wavelength of 560.50 nm, blue methylene has used too for finding a surface area. Freundlich and Langmuir isotherm model has used to find best isotherm model. The isotherm model suitable for adsorption this time is the Freundlich isotherm model because it has a linear line equation that is y = 0.4784x + 3.3971 with the correlation coefficient (r) is 0.9922
Properties of silica reinforced unsaturated polyester composite: The effect of filler content
Authors: Nasution H. , Harahap H. , Pandia S. , Wijaya F. , Al Fath M. T.
Published: June 2020

The effect of filler content on the composite properties of unsaturated polyester reinforced with silica filler has been carried out. The content of the silica filler used varied from 10 to 40%. Preparation of composites was carried out by the pressing method using compression molding at a pressure of 125 psi. From the results, it was found that the content of the silica filler was very influential on the properties and characteristics of the composite. Results have shown, the flexural strength decreased with increasing content of filler, while impact strength increased with optimum value in filler content 30% weight which was 11247 J/m2. For the water absorption of composite, the increasing content of the filler led to the greater the percentage of composite water absorption. Meanwhile, the thermal stability of silica-filled unsaturated polyester composites was better than that of unsaturated polyester. The results showed that at a heating temperature of 470 °C unsaturated polyester was degraded by 90% while the composite filled with silica was degraded by 60%.
Acid-treated halloysite nanotubes filled natural rubber composites
Authors: Surya I , Masa Abdulhakim , Ismail H , Hayeemasae N
Published: June 2020

Halloysite nanotubes (HNT) filled natural rubber composites were prepared in this study. To enhance the properties of the composites, two different approaches were applied to both HNT and rubber. HNT was treated with sulfuric acid (H2SO4) while epoxidized natural rubber was also used as compatibilizer in the composite system. Effect of acid treatment of HNT on BET surface area, mechanical and morphological properties of the obtained composites were investigated. The surface area of acid-treated HNT was greater than that of untreated HNT and it increased over treating time. This has brought to an enhancement of stress at high strain especially when the strain over 500%. From the SEM images, the particle size of acid-treated HNT was seen to be finer and well-dispersed. This is attributed to the possibility of strong adhesion formation among NR, ENR and HNTs, obtaining from acid treatment.
The properties of unfilled natural rubber in the existence of alkanolamide: rheological and crosslink density properties
Authors: Surya I , Philbert
Published: June 2020

Using a semi-efficient vulcanization system; a study was carried out on the utilization of alkanolamide as a curative additive in natural rubber (NR) compounds. The alkanolamide was incorporated into the unfilled-NR compound at 0.2, 0.4, 0.6, 0.8, and 1.0 phr. The effect of alkanolamide on rheological and crosslink density properties of the NR compounds were observed. It was found that the addition of the alkanolamide exhibited shorter scorch and cure times and higher elongation at break of the NR compounds. The alkanolamide also exhibited higher torque differences and crosslink density of up to 0.6 phr of alkanolamide loading and then decreased with further increases in the alkanolamide loading.
The nano-sized montmorillonite-filled natural rubber: vulcanization and reinforcement properties
Authors: Surya I , Khosman H
Published: June 2020

One semi EV vulcanization system was applied for observing the effects of nano-sized montmorillonite on vulcanization and reinforcement properties of natural rubber (NR) composites. The montmorillonite as a nano-sized reinforcing filler was added into NR at varied concentrations i.e 2.0, 4.0, 6.0, 8.0 and 10.0 parts per hundred rubber (phr). It was found that the montmorillonite functioned as a co-curing material and reinforcing filler. It decreased the optimum cure times of the NR composites. The higher the montmorillonite concentration, the shorter the optimum cure times were. The montmorillonite also increased the torque difference, tensile moduli, reinforcement index and tensile strength. The tensile strength was improved up to an 8.0 phr. of montmorillonite concentration.
Inventory optimization in the cigarette industry
Authors: Siregar I
Published: June 2020

The increasing cigarette industry makes cigarette-producing companies continue to make improvements in inventory planning determination continuously in order to improve the effectiveness and efficiency of the company. The company sets the number of production based on a rough estimate of consumer demand in previous periods. This causes an imbalance between the company’s production capacity and the number of demands for consumers. A large accumulation of inventory causes a high carrying cost. The incompatibility in the number of demands with the quantity produced results in the emergence of the other costs so that the company loses the opportunity to get maximum profit. Therefore, it is necessary to analyse the inventory quantity to reduce carrying costs. The company optimizes the inventory quantity based on the concept of the Economic Order Quantity using the quantity of safety stock as a minimum inventory point so that the company can plan the production number in the next periods. The results showed that with the proposed inventory system a total cost savings carrying cost of IDR 722,795,625 obtained.
Minimizing damage of product using six sigma and triz methods
Authors: Boangmanalu Ervi , Abigail Triposa , Sembiring Anita , Tampubolon Jusra
Published: June 2020

Quality control of a product must be considered by all manufacturing companies to maintain product quality. One of the manufacturers of solid drug makers in the city of Medan has problems in the process of packaging/stripping. In the stripping process, there are four types of defects in X solid medicinal products that are leaky / deflated, the packaging is bad, not filled, and in the packaging, the contents are broken. To minimize defective products researchers used the Six Sigma and TRIZ methods. This study aims to determine the value of Defects Per Million Opportunities (DPMO) and sigma level and identify the risk of failure that occurs with the Failure Mode and Effects Analysis method (FMEA) and the Theory of Inventive Problem Solving (TRIZ) method as problem solvers. The result of the value of sigma level before improvement around 3.61 with the possibility of defects approximately 16981 for a million processes. Then, after improving the sigma value to 4.06 with the possibility of a process failure of 1547. The proposed improvements are training or socialization, carry out routine machine maintenance and to give the warning to monitor the performance of each operator.
Hazard identification of repetitive truck loading activities in mineral water industry
Authors: Wahyuni Dini , Panjaitan Nismah , Budiman Irwan , Dora Manurung Elisa
Published: June 2020

A good work system is one of the most important factors in the company’s progress, and is the main key to success to increase productivity, company efficiency, and reduce the risk of injury. This research was carried out in a mineral water industry located in North Sumatra. The activity of loading the product to be distributed includes lifting the gallon from the conveyor to the truck. The problem faced by the company was the lack of supervision of the appointment activities, workers complained about the muscles and skeletons due to the Manual Material Handling (MMH), and because workers were also assigned to other work stations. Complaints were identified using the Standard Nordic Questionnaire, Job Strain Index, and Rapid Upper Limb Assessment. The SNQ results show that before doing work in several parts of the body it does not feel sick, but after doing the activity arises a complaint is very sick. This shows that lifting activities are the cause of complaints. The JSI score shows an index value of 12, which means that the activity enters a hazardous job. The results of the RULA score indicate that there must be action now too. To solve this problem, Participatory Ergonomics intervention methods were carried out. PE intervention is carried out on workers who aim to get input on remedial solutions needed by workers and to management for the implementation of selected solutions.
Human error assessment in batik enterprises located in North Sumatera using HEART method
Authors: Wahyuni Dini , Theresa Sinaga Lamria , Budiman Irwan
Published: June 2020

Industry of batik has been growing since The United Nations Educational, Scientific and Cultural Organization (UNESCO) established the Indonesian batik as a world cultural heritage on October 2, 2009. Batik’s business began to develop in Java and extended to Sumatra, especially North Sumatra. North Sumatra’s Batik comes with a variety of distinctive ethnic motifs which appear attractive with ornamental motifs from various tribes in Sumatera Utara. In order to improve that industrial excellence, North Sumatra batik SMEs are required to further improve the performance, one of them through the supply chain management which are owned. The role of humans in the supply chain of the batik industry tends to be dominant, due to their role as producers, workers, and consumers. Errors caused by humans that have been found in the North Sumatra’s batik industry, such as design or color mistakes that are not in accordance with the wishes of the customer. This study aims to identify human error in the supply chain of North Sumatra batik SMEs in Medan City by adopting the Supply Chain Operations Reference (SCOR) model, namely plan, source, make, deliver, and return. The data processing was conducted by HEART (Human Error Assessment and Reduction Technique) method. The contribution of this paper is to demonstrate the use of HEART method to analyze human error in North Sumatera’s batik industry. The results of the study showed that the highest human error probability is in the process of batik motif design, cutting fabric, dyeing motif, dyeing cloth, and release wax from cloth.
Analysis of production line balancing using genetic algorithms
Authors: Ginting Rosnani , Vito Bayu Aji Indi Benedictus , Fauzi Malik Alfin
Published: June 2020

XYZ company has a problem on the production line that is the build up of work stations and bottlenecks that indicate an imbalance. The aim is to solve the problem of balancing the production line at the company. The production line using the Genetic Algorithm method is done by determining objective parameters and functions, making the encoding of the work station, determining the initial initialization according to the actual production path, then doing iteration with selection, crossover, and mutation to form a new population, and ending with the termination of the algorithm. The results of the actual production line obtained are the number of work stations as many as 8 work stations and with the largest cycle time of 2213 seconds. The genetic algorithm production trajectory is obtained after achieving the maximum objective function value or until the maximum iteration limit is reached and consists of 7 work stations with the largest cycle time of 2203 seconds, and has a higher efficiency value thereby minimizing idle time, having a higher value of balance delay low so that it shows a decrease in waiting time and a lower value of the smoothing index compared to the actual production line where the production line is more balanced, meaning that the division of work elements is quite evenly distributed on the assembly line.
Balancing the production line using the ergonomic approach
Authors: Ginting Rosnani , Khatami Muhammad , Fauzi Malik Alfin
Published: June 2020

Track balance is a process of balancing production lines at a series of work stations (machinery and equipment) that need to be carried out in the product manufacturing process. This aims of this research is to form and balance the work risks allocated to each work station. If the track balance is not carried out it can lead to inefficiencies and reduce the level of flexibility of the production floor. Job Rotation (JR) is a method for designing jobs where staff learn work skills from various parts and by making changes to tasks, fatigue resulting from repetitive work tasks will be eliminated. In principle, the Region Approach method seeks to charge first to operations that have a large preliminary responsibility. Through the research conducted, the optimum trajectory is obtained using the region approach and job rotation methods where the method can produce optimum work center and can reduce the risk of excessive work. Region approach trajectory, as many as 7 work stations. In addition, the efficiency of the production line where there is an increase in efficiency of 10.56% in the region approach trajectory. Then the balance delay decreased by 10.07% in the region approach trajectory, and a decrease in the smoothing index by 298.90 in the region approach trajectory. Based on the results of the calculation of work risk using the RULA method, the results of the calculation of work risk on the work elements of each work center where the results obtained by the reduction of work elements and the addition of work elements are carried out so that the work risks at each work center are balanced, and can reduce injuries when work. Production line on the proposed condition with a cycle time of 2304 seconds and there are 7 work stations. The known value of balance delay is 18.62%, efficiency is 81.76% and smoothing index is 2015.74.
A design of bi-objective optimization model palm refinery export supply chain network: a case study in Indonesia
Authors: Tryana Sembiring Meilita , Sejati Hutapea Saut , Zaky Hadi M , Wahyuni Dini
Published: June 2020

One of the important elements influencing the export development of these products is the export distribution network produced by refining palm oil. The challenge of export distribution of palm oil refining products to generate maximum profit with minimum distribution costs, among others, is high transportation costs, distant transportation / logistics destinations, variations in product types and allocation of the number of products that must be distributed to consumers (foreign markets). The purpose of this study is to maximize profits and minimize distribution costs from the export distribution network of Indonesian palm oil refining products. Multiple goal optimization model (multi objective optimization) with the completion of soft-computing techniques is needed to solve this problem in order to get optimum results with a short solution search time. The NSGA-II algorithm (non dominated sorting algorithm II) was chosen in the completion of the existing optimization model because of the characteristics of the distribution network of export products resulting from complex refining of palm oil. The scenario used for testing the optimization model is by using a system entity consisting of three types of Indonesian palm oil refining products (Stearin RBD, Olein and PFAD RBD).