bluuebunny/crossref_metadata_2025_split huggingface dataset:
The development of maritime-based educational games for mathematics learning media
Authors: Jatmiko D D H , Hobri  
Published: March 2021

Abstract
This research was intended to develop the Android-based learning media on the system of linear equations in three variables whose theme was maritime. The results of this learning media development were reviewed based on the validity, practicality, and effectiveness. The instruments used were the media validation sheets, material validation sheets, students’ responses questionnaires, and test scores on the students’ learning outcomes. The learning media testing was given to the students of grade X at SMK Negeri 4 Probolinggo. The results showed that it was classified as the “excellent” category. The average scores of total validity obtained were 4.43 out of 5 on the learning media experts; it was then into “very valid” category. This learning media was considered very practical since the average score obtained on the students’ responses questionnaires was 4.49 out of 5. According to the test on the learning outcomes, 93.33% of the total number of students in grade X KTPI 1 scored ≥ 70 as the minimum scores. Hence, it can be said that this learning media was effective. The conclusion drawn from the research results revealed that maritime-themed educational games for mathematics learning media were valid, practical and efficient.
An analysis of undergraduate students’ higher order thinking skills in Geometry
Authors: Safrida L N , Susanto  , Setiawan T B , Ambarwati R , Hussen S 
Published: March 2021

Abstract
Higher order thinking skill (HOTS) becomes important thing and issue in teaching and learning, especially in Mathematics. By using HOTS, students could solve the complicated problems and situation that could be used in real life. So that, the students could be ready to encounter high technology developing and industry revolution 4.0. Then, students could compete with foreign students. The purpose of this study is to describe the higher order thinking skills’ students in proving geometry theorem. This study uses qualitative research and conducted to the undergraduate students. The result of this study shows that the highest HOTS score equal to 80 and the lowest HOTS score equal to 30, then the average of HOTS score is 62. The subjects with low score, only try to analyse the statement without clear reason. The subjects with medium score begin to analyse and evaluate the problem with reason although it’s not clear enough. The subjects with high score begin to create new idea in proving theorem although sometimes could explain the reason. At the end, they could draw the conclusions based on the problems.
Increased extreme rains intensify erosional nitrogen and phosphorus fluxes to the northern Gulf of Mexico in recent decades
Authors: Tan Zeli , Leung L Ruby , Li Hong-Yi , Tesfa Teklu , Zhu Qing , Yang Xiaojuan , Liu Ying , Huang Maoyi 
Published: March 2021

Abstract
Soil erosion delivers enormous amounts of macro-nutrients including nitrogen (N) and phosphorus (P) from land to rivers, potentially sustaining water column bioavailable nutrient levels for decades. In this study, we represent erosional N and P fluxes in the Energy Exascale Earth System Model (E3SM) and apply the model to the continental United States. We estimate that during 1991–2019 soil erosion delivers 775 Gg yr−1 (1 Gg = 109 g) of particulate N (PN) and 328 Gg yr−1 of particulate P (PP) on average to the drainage basins of the northern Gulf of Mexico, including the Mississippi/Atchafalaya River and other rivers draining to the Texas Gulf and the Eastern Gulf. Our model simulation shows that in these rivers PP is the dominant P constituent and over 55% of P exported by erosion comes from soil P pools that could become bioavailable within decades. More importantly, we find that during 1991–2019 erosional N and P fluxes increase at rates of about 15 Gg N yr−1 and 6 Gg P yr−1, respectively, due to increased extreme rains in the Mississippi/Atchafalaya river basin, and this intensification of erosional N and P fluxes drive the significant increase of riverine PN and PP yields to the northern Gulf of Mexico. With extreme rains projected to increase with warming, erosional nutrient fluxes in the region would likely continue to rise in the future, thus complicating the effort of reducing eutrophication in the inland and coastal waters.
Energy absorption and deformation pattern analysis of carbon fibre reinforced composite crash box under frontal load model
Authors: Primawan Prayoga Bintang , Choiron Moch. Agus , Purnowidodo Anindito 
Published: March 2021

Abstract
Crash boxes as a passive safety system in vehicles had been developed to produce high energy absorption performance. This study investigates the influence of cross-section geometry and fibre orientation angle on the composite crash box design to determine deformation pattern and energy absorption performance. The cross sections studied are circles and squares with variations in fibre orientation angles 0°, 15°, 30°, 45°, 60° and 75°. Carbon Fibre Epoxy CFS003 / LTM25 Prepegs with the type of plain woven fibre used to model crashbox structures. The computer simulation test model was carried out using a frontal load model with velocity of 7.76 m s−1. The results showed a circle cross-section at each variation of the orientation angle has a higher energy absorption than a square cross-section. Deformation patterns in each model show different characteristics including fragmentation mode, lamina bending, brittle fracturing, and local buckling as well as a combination of several patterns. The highest energy absorption obtained in the C60 model was 3.664 kJ with Specific Energy Absorption (SEA) of 36.799 kJ kg−1 and a CFE value of 0.59. While the lowest energy absorption occurs in the S45 model with 1.287 kJ which has a SEA value of 12.667 kJ kg−1with a CFE of 0.49. The CFE value indicates that the model with a circular cross section has better crushing stability than a squarecross section.
Deformation pattern and energy absorption of polylactic acid (PLA) carbon crash box under quasi static loading
Authors: Bintara Redyarsa Dharma , Choiron Moch. Agus 
Published: March 2021

Abstract
The purpose of this study is to investigate the deformation pattern and of energy absorption (EA) in Polylactic Acid Carbon Crash Box. The crash box specimen was produced by using 3D printer machine. The quasi static testing method is performed to compress the specimen with a speed of 2 mm min−1 using universal testing machine. It was pressed until it reaches deformation of 80 mm from its original length of 120 mm. The deformation was analyzed in three different variations of wall thickness (Wt), 1.6 mm; 1.8 mm; and 2 mm. The deformation pattern and the maximum EA are analyzed to determine the best design specifications. The results show that the highest EA occurs on Wt 2 mm (357.986 J), whereas the lowest EA occurs on Wt 1.6 mm (224.012 J). The local buckling and discontinue folding consist on three model of crash box. In addition, the fragmentation is also formed on Wt 2 mm of crash box but it is not looked on remain models.
Identification of damage in a ship hull sandwich plate by natural frequency
Authors: Ariesta Rizky Chandra , Zubaydi Achmad , Ismail Abdi , Tuswan  , Al-Syachri Mohammad Zircham 
Published: March 2021

Abstract
The damage of the sandwich plate occurs in the core material identification used for modal analysis on the ship hull using finite element analysis. This analysis detects the effect of damage. Five varied models using different damage percentage size is developed to ensure whether the hull is appropriate. This paper investigates the influence of the increasing damage percentage on the sandwich plate using the based natural frequencies as a parameter to determine the location of the damage. Five cases are being simulated for the damage. The location of the damage modelling used utilizing FEA software to adapt to the problems. Moreover, the sensitivity influence of percentage damage size, boundary condition, and application of spring element on the natural frequency behaviour of damage identification is also executing. The damage is detected by comparing the natural frequency reduction of the intact and damaged plate using free vibration analysis. The mode shape of the sandwich plate displayed to observe the location of damaged. The results show that the damage in the sandwich plate decrease the natural frequency and influence the mode shape, and evaluating both reveals the location of the damage.
Fatigue simulation with pedalling load and vertical load for city bike frame following British standard EN 14764
Authors: Wikarta Alief , Wahyudi Tambun Edwin Togi 
Published: March 2021

Abstract
The frame supports both the load from the rider and the riding conditions. When the loading conditions occur repeatedly, the bicycle frame will experience fatigue failure. This study discusses the fatigue simulation for city bike frames made of titanium, intending to know the safety factor and the service life of the bicycle frame according to a pedal load and a vertical load following British Standard BS EN 14764. The bicycle frame used for this research is a frame for the city bike type, where each composing tube of the bicycle frame has a thickness of 1.2 mm. The pedalling load applied to each pedal is repeated downward with 1000 N. While the dynamic load vertically downwards with a force magnitude from 0 to +1000 N. The results of the fatigue test simulation with each type of loading indicate that the titanium material with 1.2 mm thickness is overdesigned. Therefore, it is necessary to modify the bicycle frame by reducing the thickness of the frame to 1 mm on each tube. The safety value of the resulting fatigue simulation shows a decrease due to the reduction in thickness, however it still safe in terms of the material strength limit. The resulting bicycle frame after modified is lighter, where the initial mass was 6.79 kg and reduce to 3.92 kg.
Coil spring type analysis using the finite element method
Authors: Dwi Ananto Rifqi Ryandi , Andoko  
Published: March 2021

Abstract
Manoeuvre ability and driving comfort are the most important things in the automotive sector. Spring is a fundamental mechanical element that widely used in vehicle suspension applications. Holds loads perpendicular and absorbs shock loads from wheel vibrations so that they are not transmitted directly to the chassis. Therefore, the coil spring was made from a coil of high carbon steel rods in the form of a coil. The purpose of this article was to determine the differences in stress and strain strengths of several different types of coil springs. The types of springs used include the constant pitch spring, variable pitch spring, and barrel coil spring. Various types will be designed using Inventor software while the simulation used ANSYS 19.2 software. ANSYS engineering data used SUP 9 material and was subjected to a load of 6315 N. The results of the analysis showed that among the other three types, barrel coil spring has the lowest equivalent stress and maximum shear stress of 509.72 and 293.41 MPa, respectively, so it has the highest strength.
Analysis of low cycle fatigue in titanium materials 15-3-3-3
Authors: Wiryasanjani Yugo Nusa , Andoko Andoko 
Published: March 2021

Abstract
Microstructure changes of the properties of welded material effects the strength of the welds resulting in cracks and fractures in the weld joints. The 15-3-3-3 titanium alloy has excellent formability and is also cost effective in the fabrication process when compared to any other type materials. Low cycle fatigue is the dominant failure in titanium materials, requiring consideration of the design and analysis of material life. Low cycle fatigue test performed on tig welding of plate-shaped titanium material. Cyclic hardening causes an increase in the peak stress with the cycle, while cyclic softening results in decreasing the seek rate with the cycle. Cyclic loading which produces plastic strain is described as more complex and forms a hysteresis loop. Analysis of the hysteresis loop needs to analyze the stress distributions using the raindrop method in order to obtain a hysteresis loop pattern. The hysteresis loops consistently show the behavior of the material. behavior of the material. Hysteresis loop were analyzed to study the LCF property. Titanium material exhibits toughness from the start of the cycle to the end of the cycle. Second before the ‘material failure’ happens, it doesn’t show any drastic decrease in quality in the term of toughness.
Automatic baby incubator system with fuzzy-PID controller
Authors: Utomo Satryo Budi , Irawan Januar Fery , Mujibtamala Arizal , Nari Mochamad Irwan , Amalia Rosida 
Published: March 2021

Abstract
Deaths due to temperature instability often occur in premature babies. Negligent handling of new-borns can pose a risk of temperature instability as well. Therefore, interventions to keep the baby’s body temperature warm can reduce the risk of infant death. An incubator is a box equipped with a temperature controller to maintain a baby’s average body temperature. The faster nursery controlled the heat, the quicker the handling of the baby from the risk of temperature instability. This research aims to design a baby incubator that has an automatic control system for working temperatures quickly. The method to be used is Fuzzy-PID control, which functions to maintain temperature stability and accelerate the system’s response to the incubator. The temperature in the nursery is measured using a DHT22 sensor. The temperature measured from the sensor use error and delta error as input parameters in the design of the fuzzy membership set. The heater used in this study is an incandescent lamp to produce heat that is safe for babies. An experiment was carried out by comparing the PID control to determine the speed of the system response. Besides, measurements to assess the stability of the controller are also carried out by analyzing the effect of the load on temperature variations. The test results show a faster system response compared to the PID control and stability at a temperature set point of 32 ° C, 33 ° C, 34 ° C and 35 ° C. The time needed to achieve balance at the highest temperature of set points is 205 seconds with a max overshoot of 0.5%. With the max overshoot, the incubator can still work at a temperature that is safe for babies.
Design of a single-phase flux radial generator with opposite poles (U-S) using permanent Neodymium magnet (NdFeB)
Authors: Utomo Satryo Budi , Irawan Januar Fery , Hadi Widyono , Amam Dendy Sandrolis 
Published: March 2021

Abstract
Nowadays, the energy crisis is one of the main problems in Indonesia. The depletion of fossil fuels is the most dominant factor. Therefore, new energy solutions are needed. Generators are an essential factor in renewable energy in generating electricity.Further research is required to create a generator that may work at low rotational speeds. Electricity supply service from year to year continues to increase in any hemisphere due to the needs of the community that separated from the demand for electrical energy, especially in Indonesia. There are still many regions of Indonesia that have not to be electrified, especially remote areas, borders, and outer islands. Thus, alternative energy sources are needed, such as new and renewable energy, as electricity producers. One effort to overcome the scarcity of electrical power is the use of water and wind energy in electricity generation both on a large scale and on a small scale. Indonesia has considerable wind potential related to the energy sector, but this system also requires batteries or energy storage media. Innovations on energy conversion technology, especially in permanent magnet NdFeB permanent radial and axial flux generators have been developed. An electric generator is a device that can convert mechanical energy (motion) into electrical energy. In designing radial flux generators with opposite poles, they have 24 coils on the stator and 12 magnets on each rotor, where each coil has 450 windings connected in series with 24 Neodymium Iron Boron (NdFeB) magnets on the rotor. The diameter of the email wire used in this generator is 0.3 mm. Tests carried out using a resistive load of 3000 Ω, which is paralleled as much as 1, 2, and 3 as a load. Tests carried out on the voltage, current, and rotational speed of the rotor to determine the power and efficiency of the generator. The test results show that this magnetic flux change produces a voltage of 101 volts without load.
A strength analysis of conventional and sandwich plate deck using finite element method
Authors: Ismail Abdi , Zubaydi Achmad , Piscesa Bambang , Panangian Ervan , Ariesta Rizky Chandra , Tuswan Tuswan 
Published: March 2021

Abstract
Ship materials are required to have good strength but with the lightest mass possible. The faceplate layer is made of a material with high strength and stiffness, while the core layer is made of a material with lower strength, stiffness, and density. In this study, a PU composite was applied to ship sandwich plates. Strength analysis was carried out to determine the feasibility of applying the sandwich plate to the oil tanker deck using the Finite Element Method. Sandwich plate deck has a stress value of 139.73 MPa. When compared with conventional models, the difference in stress reaches 80.26 MPa or about 36.48% of conventional models. The highest stress on the sandwich model meets the permitted stress. This study proves that the sandwich plate system (SPS) could reduce stress in the tanker deck structure. Steel faceplate and polyurethane elastomer composite cores have outstanding potential to be applied as sandwich plate systems on ship decks.
A comparative study of conventional and sandwich plate side-shell using finite element method
Authors: Ismail Abdi , Zubaydi Achmad , Piscesa Bambang , Panangian Ervan , Ariesta Rizky Chandra , Tuswan Tuswan 
Published: March 2021

Abstract
Ship material technology needs lightweight and strong enough material, where one of the solutions is a sandwich plate. Steel faceplate and room temperature cured polyurethane elastomer (RTC-PU) cores are frequently used configurations on ship sandwich plates. But RTC-PU has a relatively high cost. Polyurethane elastomer casting has a lower cost and easy-to-obtain. More economical core materials can be achieved by combining casting polyurethane elastomer with fiberglass, so fiberglass-reinforced polyurethane elastomer (FRPU) composite is obtained. In this study, FRPU is used as a core for ship sandwich plates. Strength and weight assessment of conventional and side-shell sandwich plates were performed to determine the benefits of applying the sandwich plate to side-shell tankers using the Finite Element Method. The application of the sandwich plate results in a stress reduction of 27.02% and a weight reduction of 4.2% compared to conventional side-shell structure. The highest stress of the side-shell sandwich plate is below the steel yield stress so that the sandwich plate is acceptable for the side-shell structure. The implementation of sandwich plates can reduce the weight of ship structure so that the ship’s payload can be increased and its operation will be more efficient.
Experimental investigation of the area ratio of double-layer blades as obstacle blades on swirling savonius rotor performance
Authors: Siregar Indra Herlamba , Effendy Moch , Akhmad Hafizh A R 
Published: March 2021

Abstract
The effect of the area ratio of the double layer obstacle blades to the performance of the swirling savonius rotor model has been identified. There are 4 studied ratios of 1: 6,2: 6, 3: 6 and 4: 6 which are equivalents to 300, 600, 900 and 1200 of the double layer obstacle blades arc angles in wind tunnels with wind speeds between 3 m s−1 to 6 m −1 which is equivalent to Reynolds number 56323 to 112645. The results of the study show that a small ratio of 300 and 600 blades arc angles can improve the performance of swirling savonius rotor, especially at Reynolds number 112645. Besides that, the existence of double-layer obstacle blades can increase the resistance of swirling savonius rotor toward the load.
Shrouded wind turbine for low wind speed
Authors: Nasrul Muhammad , Rizianiza Illa 
Published: March 2021

Abstract
The problem of electrification in Indonesia for remote areas is difficult to access and far away from the grid of PLN, so an alternative is needed to overcome this problem. One alternative to this problem is to build off-grid power plants by utilizing natural potential in an area such as wind energy, but not all regions have sufficient wind speed to use wind turbines, so the wind turbine must operate at low wind speeds with good efficiency. Shrouded can be used to increase the efficiency of conventional wind turbines, even at low wind speeds. In this study, the shrouded wind turbine can increase power output by up to 92.71%, with an average of 62.91% compared to conventional wind turbines under wind speed conditions of 2 m s−1 - 6 m s−1.
Evaluation of single stage centrifugal pump performance 103-P-509B after 26300 hours of use
Authors: Yohanna Eflita , Rozi Khoiri , Yulianto Mohamad Endy , Fikri Hafiz Rachmad , Muliyawan Anggi 
Published: March 2021

Abstract
Centrifugal pump is a type of pump used in low viscosity fluids. Therefore centrifugal pumps are widely used in the petroleum industry and power plants. At the Residual Fuel Catalytic Cracking (RFCC) there are 103-P-509A and 103-P-509B centrifugal pumps that function as cosolvent circulation media on the 103-V-503 vessel. To circulate cosolvent 103-P-509A and 103-P-509B pumps are arranged in parallel. While the operation of the 103-P-509A, pump impeller has become porous and destroyed. So it is necessary to know the actual performance of the 103-P-509B pump through analysis with analytical methods to process data and then compare it to the design performance. After calculating and comparing with the design performance, the differential head increases by 0.2 m, the decrease in NPSHa and NPSHr are 53.6 m and 0.62 m, and the pump efficiency decreases by 2%. Cosolvent circulation process does not experience interference, but the time needed to circulate cosolvent becomes longer. It can be concluded that the impeller pump 103-P-509B is in good condition.
Co-combustion characteristics of low-rank coal mixed with candlenut shell by using Thermogravimetry analysis - differential thermal analysis
Authors: Patabang Daud , Siang Jeri T. , Basri  
Published: March 2021

Abstract
CNS is one of the plantation wastes that can be used as alternative fuel which can be mixed with LRC. The research aims to obtain thermal and chemical characteristics of LRC – CNS mixing and the impact of adding CNS into LRC on combustion characterization. An experimental test was conducted to obtain thermal characteristics by using proximate and ultimate analysis based on ASTM standard. Combustion characteristics are obtained by using differential thermal analysis (DTA) and thermal gravimetry analysis (TGA) by using air as an oxidant. The Composition of CNS mixtures with LRC are 10, 30 and 50 respectively. The result of CNS mixed with LRC generalized improves the quality of the fuel mixture by the increase combustion reactivity, and this has an impact on increasing differential internal energy. The optimum addition of CNS into LRC was obtained of 10%.