bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of voltage bias on the yield and electrical properties of Exfoliated Graphene synthesized via electrochemical method
Authors: Abdillah O B , Floweri O , Iskandar F 
Published: March 2021

Abstract
Graphene has been gaining immense attention from scientists over the world for its exceptional properties, which makes it promising for several applications such as energy storage, electronic devices, and biomedicine. Graphene synthesis via the electrochemical exfoliation route offers a cheap, simple, eco-friendly, and scalable process for industrial purposes. In this work, the effect of voltage bias during electrochemical exfoliation on the electrical properties and yield of the obtained exfoliated graphene (EG) was studied. Graphite sheet as raw material was pre-treated by immersing it into H2SO4/H2O2 mixture before the electrochemical process. By applying the optimum voltage of 10 V, the electrochemical method was able to produce EG with yield as high as 40.95% in a relatively shorter time. Moreover, EG also demonstrated the highest electrical conductivity of 25.45 S/cm.
Nature of Science learning design for elementary school students
Authors: Yuniasih N , Widodo A 
Published: March 2021

Abstract
This study aims to describe the increased understanding of NOS students after the application of the Nature of Science learning design. This study uses a pre-experimental research with a one-group pretest-posttest design research design. The number of samples in this study were 29 students. The research instrument used in this study was in the form of students NOS understanding questionnaire. The results showed that the level of understanding of NOS students got a percentage of 77,5% means that with this percentage students understanding of NOS is included in both criteria. The results of the study also showed a significance value of 0,000 <0.05 then H0 was rejected and H1 was accepted so that it could be concluded that there were significant differences between students NOS understanding before and after learning by using the NOS learning design. In accordance with these results it can be concluded, the teaching of NOS in Elementary Schools can be done effectively through the use of appropriate learning designs, so as to improve students NOS understanding.
Performance of fan chips on drilling aluminium process
Authors: Sifa A , Suwandi D , Endramawan T , Rachman A A 
Published: March 2021

Abstract
The metal fabrication process, especially in the metal drilling process, one of the parameters that affect the quality of metal drilling results is cooling media, because it affects the life of the tool used. This paper aims to determine the performance of using fan chips as an alternative to cooling media in the metal drilling process area. The method used with flow simulation and drilling process experiments on workpiece made from aluminum alloy 5086 in experimental testing uses a variation of the spindle rotation of a metal drilling machine with the aid of taking test data with an anemometer and infrared thermometer in the drilling process of the aluminum alloy 5086 workpiece. After experimenting with chips through spindle rotation variations, cooling of the process area occurs when the engine spindle rotation rotates above 1000 rpm and the temperature decreases at the end of the tool area by 5°C compared to without using fan chips. A decrease in the temperature of the work area of the drilling workpiece aluminum alloy 5086 compared without using fan chips has an impact on increasing the tool life limit by 12% or increasing tool life by 5 minutes.
Flame spread simulation of fire occurrence at motorcycle parking building
Authors: Setyadi P , Yoga N G , Kusumohadi C S , Triyono T , Nanda Y F 
Published: March 2021

Abstract
This research is motivated by the condition of the parking building in A Campus, State University of Jakarta that development that very compact and crowded with wide openings. This study aims to estimate the flame spread of motorcycle parking. This study used computer fire modeling by simulating flame starting point and direction of the wind, numbers of fuel source and forms. This research will discuss about the development of the fire where the fire development will be represented by HRR (Heat Release Rate), burning rate, and visualization of each simulation. This step is very advantageous because it can figure out how the spread of fire during a fire and how fire simulated. With the fire of this modeling can be a practical engineering approach to provide additional review of aspects of fire safety on campus parking building at Jakarta State Univeristy. From these results it can be concluded that the rapid spread of the fire affected by the starting point of fire, wind speed and direction. HRR where the greater value the greater the value of burning rate obtained and the greater the level of occurrence of fire.
Optimum parameters of Organic Rankine Cycle (ORC) power plant using coconut shell as fuel
Authors: Harmiansyah H , Hartulistiyoso E , Widodo S , Nugroho L P E 
Published: March 2021

Abstract
The scarcity of energy sources is an important issue now. The increasing number of populations causes higher energy needs. The use of renewable energy as an alternative is a good solution. Organic Rankine Cycle (ORC) is a Rankine cycle that can work at low temperatures and pressures. The working fluid of ORC is an organic one such as R-134a refrigerant; because its boiling point is lower than that of water and has low environmental impact. In this study, work simulations were performed by using Cycle Tempo software to analyze the performance of the ORC system using coconut shells and to obtain optimum parameter variations based on thermal efficiency values. The simulated data consists of 12 variations of fuel rate parameters and mass flow rate. Based on the simulation results, 2.5 kg 2 GPM variation is obtained as the optimum parameter variation with a thermal efficiency value of 6.17%.
Analysis of number propeller blades on traditional boats 3 GT capacity with engine rotation speed variation
Authors: Endramawan T , Sifa A , Dionisius F , Rachman R D 
Published: March 2021

Abstract
Limited range of fishing areas is one form of loss experienced by fishermen in Indonesia, especially fishermen who still use traditional boats 3 GT capacity. The driving component of one of the problems, one of which is a propeller. Propeller commonly used by fishermen still uses 3 blades propeller with less than maximum thrust distribution and fluid velocity. The purpose of this study is to optimize the number of propeller blades in traditional boats 3 GT capacity with variations in the number of propeller blades 2,3 and 4 and rotational speed of 700 RPM, 1200 RPM, 1700 RPM, and 2200 RPM. The method used to determine the amount of thrust and fluid velocity through CFD simulations. Flow simulation results show the maximum thrust obtained at 1700 RPM rotational and the maximum fluid velocity obtained at 2200 RPM with a pressure of 15.3Mpa and a fluid speed of 3340.16 m/s on a propeller of 2 blades. Whereas the minimum thrust force is obtained at 700 RPM rotational with pressure 0.21Mpa in propeller with 3 blades and the minimum fluid speed is obtained at 700 RPM rotational with a fluid speed 369.33 m/s on propeller with 4 blades.
Analysis of ST-37 metal cutting with machine-cut tools using Oxy-LPG
Authors: Tauvana A I , Widodo W , Subekti M I , Syafrizal S , Nulhakim L 
Published: March 2021

Abstract
This gas cutting machine is a ST-37 metal cutting tool in a semi-automatic way using LPG and Oxygen gas materials. LPG gas is used with a composition of propane 99,5% and Isobutan 5%. In the process of cutting metal must pay attention to several parameters, namely: metal thickness, oxygen gas pressure and LPG gas and cutting speed. Before cutting down the metal, the preparation stage is done by conditioning the test equipment and work equipment used to collect test data. The method used in this research is to select the type of metal and cutting equipment then do the recording and taking test data. Further analysis and examination are carried out as follows: visual inspection of the results of cutting and flame shape, a better composition results from testing in accordance with applicable rules such as pressure, plate thickness and time of cutting. 99,5% and 0,5% LPG gas composition at gas working pressure: 0.2 kg / cm2; oxygen pressure: 2.5 kg / cm2, cutting distance of 2mm. The results of this test are overall in good condition and no defects occur.
Optimization of relative density to geometric parameter ratio for honeycomb structure using Finite Element Analysis
Authors: Octarina A J , Saptaji K , Kurniawan T 
Published: March 2021

Abstract
Honeycomb structures are becoming preferred choice for increasing the efficiency of automotive, aerospace, construction and other related industries as it provides low-density ratio to specific strength. Out-of-plane orientation honeycomb core structure has significant advantage in load-bearings and energy absorption. However, previous studies were mostly focusing on the specific strength of the structure. In this paper, optimization of relative density to geometric parameter ratio for honeycomb structure is conducted with the focus on compressive properties. It is expected that high compressive properties with low relative density can be achieved. Relative density and geometric parameter are obtained from RVE (Representative Volume Element) which affected by variable-thickness. Finite Element Analysis (FEA) using ANSYS software were conducted to simulate compression test with 300kN compressive load to the honeycomb structure with various ratios. FEM results illustrate that relatively higher geometric parameter tends to have higher compressive properties. Initial analysis shows that structure with the lowest ratio of relative density to geometric parameter of around 22.70% has higher equivalent elastic strain and equivalent stress around 0.50896 and 1.7152 GPa compared to other parameters.
Armadillo modelled foldable motorcycle helmet: A preliminary design concept for rider in Indonesia
Authors: Maulidati N , Cahyo A D N , Irodatillah K , Triawan F 
Published: March 2021

Abstract
Safety is an important thing while riding a bicycle or motorcycle. Using a helmet is one of the solutions to increase safety of the rider, but sometimes people are too lazy to bring the helmet because of its big size. In the present work, a foldable helmet adopting the Armadillo concept was proposed to make people feel more comfortable in carrying the helmet. The design also follows the safety standard required by the SNI (Indonesia National Standard). A locking system for the folding mechanism is discussed, and a honeycomb foam for impact absorber is considered in the design. As a result, the proposed foldable helmet can have a reduction volume of 23.75% compared with the non-foldable one. This work is expected to contribute to the innovative engineering design field.
Performance analysis of R290 as a substitute for R404A on 12,000 Btuh cold storage capacity
Authors: Widodo W , Syafrizal S , Tuvana A I , Subekti M I , Nulhakim L 
Published: March 2021

Abstract
Cold Storage is a machine that has a very low temperature:-30°C which is used for the freezing process. Cold storage used for this research has a capacity of 18,000 Btuh with R404A. This refrigerant does not contain ODP but still contains a very high GWP: 3940 compared to R290. R290 (propane) is GWP:4 and ODP:0. But this refrigerant has flammable properties between LFL-UFL: 2-10%. The cold room dimensions: 3 x 1.5 x 2.5:11.25m3. The testing methodology by comparing the performance of R404A with R290 cold storage conditions was tested without using a cooling load with a room temperature setting of -29°C, room temperature of 35°C and RH: 70%. Time Testing is carried out for 90 minutes. From the test results obtained data: evaporator temperature: -29°C with a time of 68 minutes for R290 and 95 minutes for R404A, LP: R404A / R290: 12/6 Psig, discharge pressure: 215 / 175 Psig and the amount of refrigerant entered in the system: 3500/1800 grams and electric current: 4.1/2.9 Amperes. From the data analysis, it can be concluded that R290 has better performance, energy-saving, and environment friendly compared to R404A.
Effects of the superficial gas velocity on the distribution of solid particles in the circulating fluidized bed using CFD simulations
Authors: Daryus A , Siswantara A I , Budiarso B , Pujowidodo H , Gunadi G G R 
Published: March 2021

Abstract
The purpose of the study is to investigate the effects of various air flow rate or superficial gas velocity in term of excess air to obtain the optimum distribution of solid phase in the Circulating Fluidized Bed (CFB). The Computational Fluid Dynamics (CFD) method used for simulations uses the Multi-fluid Eulerian approaches incorporating the Kinetic Theory of Granular to calculate the motion of particles and the standard k-ॉ turbulence model to simulate the fluid flows. The simulations were carried out using five different air mass flow rates, based on the air consumption in the combustion of coal used in real CFB boiler operation. Since this simulation is the preliminary study of the particle dynamics in CFB, the combustion process had not simulated yet. In this work, the complex flow has been resolved by applying the CFDSOF commercial CFD software. The pressure on bed, the distribution of pressure, the particle velocity and volume fraction in the CFB were investigated to obtain the optimum results of the fluidization. The values of the pressure found from experiments at the bottom of bed was around 4,500 Pa, and the results from simulations were not different significantly with this values. At the excess air of 90%, the velocity of particles at the surface of bed is highest that can lead to the erosion on the firewall in long term operations, meanwhile at the lower excess air values, their velocity were relatively small. The optimum of excess air that found to be safe for boiler to operate was around 60% - 75% for average particle size 1 mm.
Investigations on properties and tribological behavior of AlMg4.5Mn0.7(AA5083)-MoO3 composites prepared by stir casting method
Authors: Anandaraj T , Sethusundaram P P , Meignanamoorthy M , Ravichandran M 
Published: March 2021

Abstract
Molybdenum Trioxide (MoO3) has received extensive consideration as a prospective reinforcement for metal matrix composites (MMCs) to improve the properties. The goal of this work is to fabricate and examine the properties of AA5083-MoO3 composites. AA5083-MoO3 composites by several weight percentages were produced via liquid metallurgy technique. The compositions of the composites are AA5083, AA5083-4wt.%MoO3, AA5083-8wt.%MoO3 and AA5083-12wt.%MoO3. The microstructure inspection was made on the synthesized AA5083-MoO3 composites using Scanning Electron Microscope (SEM). The effect of MoO3 weight percentage on the properties such as density, porosity, mechanical and wear behavior were investigated. The SEM images expose the even dispersion of MoO3 particles with AA5083 matrix. The combination of MoO3 particles enhanced the properties of the composites. The wear behavior was examined via pin on disc apparatus at various process parameters wt.%, load, sliding velocity (V) and sliding distance. Trials were conducted as per L16 orthogonal array (OA). Optimum process parameters to acquire least wear rate and co-efficient of friction (COF) was done by Grey Relational Analysis (GRA). The ANOVA results exposes that wt.% is the major important parameter inducing wear and COF.
Exploration of PTFE sub-micron particles for enhancing the performance of commercial oils
Authors: Solanki Raghavendra , Saini Vinay , Bijwe Jayashree 
Published: March 2021

Abstract
This paper reports on the tribo-performance enhancement of commercial gear oil and engine oil by inclusion of PTFE particles of submicron (230 nm) size (SMPs). It also reports on the investigations on various concentrations of SMPs to find the optimum doses. Results revealed that optimum dosage of 6 and 3 wt.% SMPs led to a significant improvement in EP property by 175% and 58% respectively in Engine oil and Gear oil. The EP performance of PTFE added engine oil surpassed that of PTFE added-gear oil confirming that it can be used as multipurpose oil. Importantly anti-wear and anti-friction properties also showed improvement confirming no antagonistic influence of PTFE particles on selected commercial oils. Synergistic action between SMPs and other additives led to formation of stable tribo-film as a result of chemical interaction of mating surfaces. The mechanisms involved were analyzed by investigating worn surfaces using SEM-EDX, x ray photoelectron spectroscopy (XPS) techniques. The stability of suspension in case of engine oils was up to 2 months and for gear oil it did not show any deterioration in the observed period of 4 months.
Effect of FSP on mechanical properties, wear and corrosion behavior of A356 Al alloy
Authors: Hasona Khadija M , Afify Rasha M , Mansour El-Sayed H , Gaafer Ahmed M , Mahmoud Tamer S , Mosleh Ahmed O 
Published: March 2021

Abstract
Grain refining and microstructure homogenization are fundamental challenges for enhancing the performance of the materials. One of the effective ways to solve these challenges is the Friction stir processing (FSP) technique. This paper investigates the FSP parameters’ impact on the microstructure, hardness, wear, and corrosion behavior of A356 Al–Si cast alloy. The FSP parameters are rotational speed (355–900 rpm), trasverse speed (10–40 mm min−1), and two different tool geometries. The results revealed that the intense plastic deformation and dynamic recrystallization fragmented the needle-shaped eutectic silicon particles. The particle size change was more pronounced as the rotational speed was increased than the transverse speed and the pin profile tool geometry. The fragmented and homogeneously distributed Si particles in the investigated alloy increased their hardness, wear, and corrosion resistance compared with those of the unprocessed base metal. The hardness increased by two times, and the wear rate reduced by ten times, while the corrosion rate decreased by 200 times than the BM at lower tool rotational speeds and higher transverse speed. The Possible reasons were discussed for these enhancements.
Molecular dynamics simulation of monocrystalline copper nano-scratch process under the excitation of ultrasonic vibration
Authors: Jian-Hao Chen , Qiu-Yang Zheng , Zhen-Yu Zhou , Cong Ding , Zhong-Yu Piao 
Published: March 2021

Abstract
In order to explore the mechanism of unidirectional ultrasonic vibration-assisted machining from a microscopic point of view, the molecular dynamic (MD) simulation method is used to simulate the scratch process of monocrystalline copper under ultrasonic excitation. By comparing the simulation results of traditional scratching and ultrasonic vibration-assisted scratching, the influences of ultrasonic vibration on the surface morphology, the tangential force, and the evolution of the crystal’s internal defects are discussed. The results show that the ultrasonic vibration can improve the surface quality of the workpiece, reduce the tangential force, and reduce the energy consumption. Simultaneously, ultrasonic vibration promotes the interaction between dislocations, accelerates the annihilation of dislocations, effectively reduces work hardening caused by dislocation accumulation, and forms a large number of vacancies and interstitial atoms.
Study on the effect of singlewalled carbon nanotubes on junction properties of Safranin –T dye-based organic device
Authors: Sen Sudipta , Kumar Das Pallab , Manik N B 
Published: March 2021

Abstract
In this work, junction properties of metal-organic dye contact have been studied and alteration of these properties in presence of single walled carbon nanotubes has been observed. Junction properties of metal-organic interface significantly influence the device performance. Present work studies barrier potential and trap energy under the influence of single walled carbon nanotubes. Barrier inhomogeneity and the effect of image charge on lowering of barrier potential have also been studied. Formation of the organic device has been done by sandwiching Safranin - T dye in between two electrodes which are Indium Tin Oxide coated glass substrate and Aluminium respectively. Charge flow at the metal–organic layer interface has been analyzed by Richardson –Schottky thermionic emission theory. Both barrier potential and trap energy have been estimated from the steady-state current-voltage characteristics of the device. The incorporation of single walled carbon nanotubes lowers both of these parameters results in improvement of current flow at the metal-organic contact.
Piezoelectric property investigation on PVDF/ZrO2/ZnO nanocomposite for energy harvesting application
Authors: Naik Rahul , S Mohit , Chavan Santosh 
Published: March 2021

Abstract
Recent days, considerable research efforts have been emphasized on the development of lightweight, portable, shock resistance, and flexible wearable devices that are powered by harvesting energy from abundant mechanical forces or vibrational energy. In this paper, we report piezoelectric nanogenerator (PNG) based on poly (vinylidene fluoride) (PVDF)/Zirconium oxide (ZrO2)/Zinc oxide (ZnO) nanocomposite. The addition of nanofillers significantly affects the structural property of PVDF, and their addition helps in the improvement of the piezoelectric property. The PNGs are fabricated and tested under various stress conditions (at different loads, tapping and walking). The hybrid PVDF/5% ZrO2/5% ZnO nanogenerator showed a maximum peak to peak voltage (Vpp) of 3.2 V, which is nearly eight times more than pristine PVDF nanogenerator. A prototype of shoe pad nanogenerator is demonstrated as an application.
Spectral broadening and ultrafast dynamics of a nitrogen-vacancy center ensemble in diamond
Authors: Liu Albert , Cundiff Steven T , Almeida Diogo B , Ulbricht Ronald 
Published: March 2021

Abstract
Many applications of nitrogen-vacancy (NV) centers in diamond crucially rely on a spectrally narrow and stable optical zero-phonon line transition. Though many impressive proof-of-principle experiments have been demonstrated, much work remains in engineering NV centers with spectral properties that are sufficiently robust for practical implementation. To elucidate the mechanisms underlying their interactions with the environment, we apply multi-dimensional coherent spectroscopy to an NV center ensemble in bulk diamond at cryogenic temperatures. Our spectra reveal thermal dephasing due to quasi-localized vibrational modes as well as ultrafast spectral diffusion on the picosecond timescale. The intrinsic, ensemble-averaged homogeneous linewidth is found to be in the tens of GHz range by extrapolating to zero temperature. We also observe a temperature-dependent Stark splitting of the excited state manifold, relevant to NV sensing protocols.