bluuebunny/crossref_metadata_2025_split huggingface dataset:
A mathematical model for solar cookstoves: the relation between thermal and optical parameters
Authors: Servín H , González-Avilés M , Sobral H , Peña-Gomar M 
Published: March 2021

Abstract
The article presents a mathematical model that relates the thermal properties of a concentration solar cooker with some optical properties of several of the materials used in its elaboration. Solar cookers are studied from the point of view of its functionality through their thermal performance, in terms of calculating the standard cooking power and thermal efficiency with field tests. Some of the materials characteristics that are important to make concentrating solar stoves are: the reflectance of the surface of the concentrator, the transmittance of the cover and the absorbance of the surface of the food container. Through an analysis of heat transfer, it is built a model for calculating thermal parameters depending on the optical parameters. A comparison of the model is made by varying the absorbance and reflectance of the coating that covers the food container. The results of the model agree with those found experimentally.
Optical Characterization of Biomass Soot Samples
Authors: Peña-Gomar M , Sobral H , Servin Campuzano H , González-Avilés M 
Published: March 2021

Abstract
Soot from different biomass sources is investigated to develop absorbent coatings for use in solar cookers. Soot samples were analysed by spectral and solar reflectance in the range 280-2400 nm, by its organic elemental composition and through Raman spectroscopy. The soot was obtained from biomass burning of sugarcane, pine resin and firewood in a hearth. The averaged spectral reflectance for sugarcane soot is 3.5%, for wood-stove soot is 2.7% and the lower value corresponds to pine resin soot at 1.4%. Likewise, the lowest value of the solar reflectance was of 14.8 Wm−2 for pine resin soot. In addition, elemental composition analysis showed that pine resin also has the highest carbon content. Raman spectroscopy measurements were performed to find the structure and the degree of disorder in the graphite structure.
3-D printing of crystal and polycrystal physical properties
Authors: Batista-Fierro B , Duarte-Ortiz C A , Villalobos-Portillo E E , Fuentes-Cobas L E 
Published: March 2021

Abstract
The article contains a compact summary of cause-effect relationships regarding the structure-properties link in crystals and polycrystals. Neumann’s principle is addressed and visualized in tensor and longitudinal surface treatments. Properties databases and representation algorithms are presented. A software package for 3D printing of physical properties’ surfaces, as a helpful tool for anisotropy visualization, has been created. The required parameters and equipment are disclosed. The article includes examples of experimental data obtained from the MPOD database and several practical illustrations.
N-AcetylLaspartic Acid Phantom for Proton Magnetic Resonance Spectroscopy at 1.5 T and 3 T
Authors: Martin R , Marrufo O , Solis-Najera S , Rodriguez A O , Vazquez F 
Published: March 2021

Abstract
Proton Magnetic Resonance Spectroscopy (MRS) phantoms are an important tool for quality assurance and reliability. Some of the contents are not easily available in some countries due to some company policies. We built a phantom using N-Acetyl-DL-aspartic acid as a substitute for N-Acetyl-L-aspartic acid for proton magnetic resonance spectroscopy of human brain at 1.5 T and 3 T. To quantify the B0 homogeneity, phase and magnitude images of a commercial phantom were also acquired with a standard gradient echo sequence. Spectra obtained were corrected and dismissed critical chemical shift due to inhomogeneities. Spectra numerical simulations at 1.5 T and 3 T were performed using a free jMRUI and point resolved spectroscopy sequence for various times of echo. In vitro single-voxel spectra were obtained with the phantom prototype and a commercial phantom using the substitute acid and the same pulse sequence and magnetic field magnitudes as before. Simulated and in vitro spectra showed a very good concordance and majority of metabolites were readily identified for both fields. Spectra acquired with the phantom prototype complied with those quality control criteria for clinical use for both field strengths. This approach offers an alternative way to conduct clinical magnetic resonance spectroscopy.
Gas measurement system for Bio-hydrogen production based on nejayote’s dark phase fermentation
Authors: Tavera-Romero F , Ríos-Maravilla A , Granados-Samaniego J , Turpin S 
Published: March 2021

Abstract
Nejayote is the residual water from the corn nixtamalization process, this is considered a pollutant when it is discharged into the public sewer system due to its high demand for oxygen, high temperature, and pH. There is Biohydrogen production with the use of dark-phase fermentation of nejayote in the presence of clostridius. To determine the concentrations of the different gases produced H2, CH4, CO2, was designed and build a data acquisition system on Lab View development platform, using MQ-X type sensors and Arduino UNO prototyping board. Was adapted an airtight plastic container with capacity of 30 ml with special nozzles to allow multiple needle entries and injections of different samples. This device allows us to quantify the biohydrogen obtained from the various concentrations used in the reactors to obtain the optimal mixture.
Index development with the keyword in context method in the online library catalog
Authors: Safii M , Martutik  , Harsiati T , Kurniawan T , Asari A , Rahmania L A , Prasetyawan A , Arraja Y G 
Published: March 2021

Abstract
Academic libraries have an essential role in the academic community. As a reference center, libraries provide access to online reference sources or book collections. One of the facilities provided is the library automation which facilitate users to access library resources. With an online catalog that is easy to operate, it will be easier for users to get information. However, libraries generally only provide interface search facilities which make it difficult for users to find information. This study aims to produce an index on the online library catalog using the KWIC (KeyWord in Context) method. The data was collected from the Open Archive Initiative Protocol for Metadata Harvesting (OAI-PMH) on the Library server. In the data harvesting process, around 50,000 data were found to be processed. The finding in this study indicates that the library’s online catalog metadata index makes it easier for users to retrieve information.
The design of learning media using JavaScript and its implementation in the local web server
Authors: Laini S , Kalam A N , Anjelina S , Alfat S 
Published: March 2021

Abstract
The ranking of Indonesian science competencies at the global level in 2018 was in the 70th of 78 countries. The low student learning activities is one of the trigger factors. One impacts the use of learning media which is not appropriate, such as decreased learning motivation which ultimately impacts the low student learning activities. This research intends to design learning media based on offline using JavaScript programming language and combined in a local network system. The method used is Research and Development. The specifications of the tools and materials used are MAC Mini Intel Core I7 Quad-Core 3.6 GHz, 16 GB DDR4 memory, and SATA 2 TB HDD. The use of learning media is expected to overcome several problems in conventional learning and become one of the solutions to distance learning systems.
The development of the implementation of discovery learning and the influence to the student’s conjecturing ability to solve local irregularity vertex coloring in graphs
Authors: Nikmah N , Kristiana A I , Dafik  , Hobri  , Slamin  
Published: March 2021

Abstract
This research aims to explain about development of the implementation of discovery learning and the influence of student’s conjecturing ability to solve local irregularity vertex coloring in graphs. Discovery learning is one of the learning model that can be used to improve the ability of students to conjecture in solving mathematical problems. For processing of data their conjecturing ability using a triangulation methods, namely a combination of qualitative and quantitative methods. Students majoring in Mathematics Education at Jember University are research subjects. Subjects of this research using experimental class and control class. Different treatments are offered to both class. This research results findings indicate that there is a major gap between both class implementing discovery learning and teacher centered learning.
An analysis of STAD cooperative learning implementation and its effect on the collaborative skill in solving the problems of addition and subtraction
Authors: Supratiningsih  , Dafik  , Farisi M I 
Published: March 2021

Abstract
Collaborative skill is needed in 21st century era. However, there is an indication that the learning model has not been able to improve the collaborative skill. This research was intended to analyze the implementation of Student Team Achievement Division (STAD)-based learning instruments and its effect on the students’ collaborative skill in solving the problems of addition and subtraction. A mixed research model was used in this research. The triangulation design which combined both quantitative and qualitative researches. As many as 28 students of class 3A were targeted as the control class and 28 students of class 3B as the experimental one. The data was collected by filling out questionnaire, observation, validation sheet, test, documentation as well as pretest and posttest. The results revealed that the percentage of students’ collaborative thinking skills in the control class after being implemented by STAD-based learning instruments covered of 57% of cooperation, 62% of responsibility, 60% of compromise, 59% of communication and 65% of flexibility. Whilst, the experimental class got better than the control class as it consisted of 83% of cooperation, 79% of responsibility, 76% of compromise, 80% of communication and 78% of flexibility. The scores obtained from independent sample t-test of post-test showed that there was a significant difference between the control class and the experimental class with a sig (2-tailed) value of 0.003 (p = <0.05). It can be concluded that the implementation of STAD-based learning instruments was able to improve the collaborative abilities of elementary school students in solving the addition and subtraction problems.
Contact pressure analysis of acetabular cup surface with dimple addition on total hip arthroplasty using finite element method
Authors: Ammarullah Muhammad Imam , Md Saad Amir Putra , Syahrom Ardiyansyah , Basri Hasan 
Published: March 2021

Abstract
This research aims to analyze the contact pressure on acetabular cup surface with dimple addition and without dimple addition. The main contribution in this research is to explore the influence of dimple addition to contact pressure that affects implant lifetime. The simulation is carried out by giving fully 3D physiological loading of the hip joint under normal walking conditions. Contact pressure analysis conducted on dry contact condition and meshing with the two-pole method performed to provide a comprehensive contact pressure result. The results show that the total hip arthroplasty model with dimple addition can reduce contact pressure for all phases in one full cycle with average decreased by 15.53% which indicates that adding dimple to the contact surface in the total hip arthroplasty bearing can extend the life of implant use.
Stress analysis bottom plate block B-03 on patrol ship construction using finite element methods
Authors: Khristyson Samuel Febriary , Jamari  , Bayuseno Athanasius Priharyoto 
Published: March 2021

Abstract
On the process of constructing ships with the block system has a tendency to dealing time production process for assembly. The waiting time makes the construction of the bottom plate to receive the burden during the waiting time so that the deformation often occurs due to excess stress received. The purpose of this study to know the stress value of the bottom construction of a block due to the static load on the ship building process. The method used is the Finite Element method is a form of the approximation method commonly used to solve an equation numerically in a stress analysis. The variables used in this study are the different types of meshing, the number of focuses on stop block. Based on the results start of the construction stress analysis Plate Bottom block B-03 on the construction of patrol ship. Obtained the highest stress value in the use of 4 stop block so, it is advisable to increase the number of stop blocks in order to reduce the results of excessive deformation.
Dimensional optimization of clutch disc with simulation of stress analysis (Study cases : clutch disc Hino FM 260Ti)
Authors: Jonoadji Ninuk , Sutrisno  , Siahaan Ian Hardianto , Simanjuntak Melvin Emil , Hamonangan Sitorus Melvin Bismark , Suryajaya Michael 
Published: March 2021

Abstract
The function of clutch disc is to transmit the power from the engine to the transmission. There are a lot of vehicle that equipped with different size of engine capacity. Therefore, it is required to use a clutch disc with the appropriate capability to transmit the power from the engine. Note that there is a clutch disc modification type that combine the Japanese and European design called clutch disc Hino MB. This type clutch disc is used for Hino FM 260Ti. By using the combination design, the clutch disc will have longer lifetime and lower risk to crack. There is a crack problem that happened from the usage of clutch disc Hino MB. Therefore, it is necessary to do a research to optimize the design of clutch disc Hino MB. This research is done by making several new designs of clutch disc Hino MB and tests it through simulation of stress analysis. The parameter that had been analysed is the value of von mises stress from each design. The length of grooves is also analysed to get a better design result. This research produces a new design of clutch disc Hino MB that has better design structure. The best result of the simulation that has been done to the clutch disc with interval 5 mm reduction is owned by clutch disc with 35 mm groove’s length reduction and the value is 121.1 MPa.
Application of semi reverse innovative design for a boot’s shoes orthotic for children with club foot
Authors: Anggoro P.W. , Nugrahanto Y.K. , Anthony A.A. , Jamari  , Bayuseno A.P. , Tauviqirrahman M. 
Published: March 2021

Abstract
Club foot is one of the foot deformities due to genetic factors, diseases, the condition of pregnant women is too small, or the result of a marriage that has a kinship. For every 1000 normal childbirths, there is usually one birth of a child with a leg like this. Children with this leg shape often have difficulty doing daily activities. In this paper, the prosthetic limbs used by children with clubfoot are very uncomfortable and often cause excessive pain. This paper comprehensively explains the process of designing boots for club sufferers using a semi-reverse innovative design (semi RID) method. The collaboration of 3D replica with Handyscann 700TM is used to get 3D mesh foot models with. STL format that is truly precise and accurate. Computer-Aided Design (CAD) with PowerShape 2019i software is used in this paper to get a variety of shoe lasts and insole designs that are truly precise and accurate according to the foot contours of clubfoot children. The results showed the error tolerance geometry was less than 5.0 mm for each dimension.
Leaf spring type simulation with finite element method approach
Authors: Kurniawan Pradhana , Andoko Andoko , Sunu Putu Wijaya 
Published: March 2021

Abstract
The leaf spring is one of the main components of the suspension system which functions as a shock absorber due to uneven road surfaces and a vibration damper from the wheels. Continuous shocks and vibrations can cause the leaf spring to receive high cyclic loads which can cause fatigue failure. The purpose of this article is to determine the differences in equivalent stress, fatigue life and safety of factor of different leaf spring types. The types of leaf springs used include the trailing leaf spring, the semi elliptical leaf spring and the parabolic leaf spring. Various types of leaf spring will be designed using solidworks software, while the simulation uses ANSYS 19.2 software. ANSYS engineering data uses SUP 9 material and the load used is 6350 N. After simulation analysis it is concluded that high fatigue life is generated by the parabolic leaf spring. with a cycle of 106, fatigue sensivity 1.996 105 cycles and a minimum safety factor of 1.1336. The safety factor value on the parabolic leaf spring shows that the component will not fail until the life design is achieved.
Simulation on the spindle of a five-axis multifunctional CNC machine using finite element method
Authors: Pradica Dhanang R. , Andoko  , Lubis Didin Zakariya 
Published: March 2021

Abstract
Computer Numerically Control (CNC) machines are manufacturing machines that are capable of cutting materials with many axes and various types of equipment and operations controlled using a computer. The analysis system used in this software is static structural with linear analysis, because the main focus is to get the value of the stress on the fastening bolts and the stress on the end mill when doing the milling process. The results of the stiffness simulation at the end mill, get the smallest stress results of 0.93783 MPa at a variation depth of feed 1 mm, and get the highest stress results of 5.6272 MPa at a variation depth of feed 6 mm. The result of spindle bolt stiffness simulation shows that the lowest value occurs at 1 mm variation depth of feed, about 1456.4 MPa for equivalent stress, 196.62 MPa for shear stress, and 0.036601 mm for total deformation. Meanwhile, the highest value occurred at the 6 mm variation depth of feed, about 1456.9 MPa for equivalent stress, 196.69 MPa for shear stress, and 0.03664 mm for total deformation. The greater the force that occurs, the greater the stress that occurs on the object, but the stress can also be smaller if the cross-sectional area is larger.
Robust protein based organic electrocatalyst for hydrogen production through instant noodle wastewater electrolysis
Authors: Willy Satrio N , Winarto  , Sugiono  , Wardana ING 
Published: March 2021

Abstract
Natural resources carbonization doping using heavy atom is the common method to synthesize organic electrocatalyst for waste to hydrogen energy conversion. This study provides one-step solution to synthesize organic electrocatalyst using enzymatic protein of Lumbricus Rubellus. L,Rubellus extract and its combination with graphite flakes in powder form are tested as electrocatalyst for instant noodle wastewater electrolysis and pre-hydrolyzed instant noodle wastewater by direct mixing. Pre-hydrolysis has doubled the hydrogen production rate for each tested catalyst. Lumbricus Rubellus extract without graphite flake mix performs better in pre-hydrolyzed wastewater. Graphite flakes form polar substrates in pre-hydrolyzed wastewater. Positive substrates inhibit the hydrogen evolution reaction of pre-hydrolyzed wastewater by electron deposition. Negative substrate inactivates L,Rubellus protein due to competitive inhibition.
Analysis of supercapacitor as a battery substitute in motorcycle
Authors: Irdianto Windra , Nauri Imam Muda , Nursalim Moh. 
Published: March 2021

Abstract
Lead acid battery is the main resource of motorcycle. It has some disadvantages, look like long charging time, short cycle life and also is not environment friendly. Supercapacitor is an electronic tool which can conserve electric current. It has higher power density compared to lead acid battery, but lower energy density. It is also faster in terms of charging, environment friendly, and has longer life cycle than lead acid battery. In this article, supercapacitor is used to substitute battery. The model is able to charge, discharge, and support engine starter in motorcycle. The result of this research shows that supercapacitor is able to substitute battery in motorcycle.
Characterization of heat transfer on concentric tube heat exchanger using ethylene glycol/TiO2 nanofluid
Authors: Irawansyah Herry , Ghofur Abdul , Subagyo Rachmat , Tamjidillah Mastiadi , Pratama Bagus Harits , Suroso Bekti , Wibowo Budi Santoso 
Published: March 2021

Abstract
This study aims to determine the effect of temperature and volume fraction on heat transfer rate and heat transfer coefficient on concentric tube heat exhanger with nano ethylene glycol / TiO2 fluid. From the results of tests and analyzes that have been done, it is obtained the best temperature and volume fraction that supports the rate of heat transfer. The best heat transfer rate of 22,430.25 W is done at the condition of the 0.03% TiO2 Volume Fraction and at a temperature of 100 ° C. The best heat transfer coefficient occurs at a volume fraction of 0.03% and at a temperature of 100 ° C. It can be concluded that, TiO2 will increase the heat capacity and heat conductivity of the base fluid which will optimize the performance of the fluid.
Performance evaluation of vertical axis hydrokinetic turbine (VAHT) helical blade using duct system for low current speed application
Authors: Amarta Zain , Ismail Abdi 
Published: March 2021

Abstract
This study evaluate the performance of vertical axis hydrokinetic turbine (VAHT) - Helical Blade using duct system. Experimental study has been performed in the open channel with measured current speed of 0.7 m s−1, 0.9 m s−1, and 1.1 m s−1. Rotational speed and torque were measured to obtain the performance factor (C

P
) and tip speed ratio (TSR). The gain of current speed has good response on rotational speed and torque. VAHT - Helical Blade using duct system has greater C

P
than non-duct system at three different current speed. The maximum C

P
is 0.44 reached on TSR of 2.92. The addition of duct system has good response on C

P
of VAHT - Helical Blade due to increasing current speed around the turbine.
Application of factorial design to analyse the effect of brick powder size on biogas purification results
Authors: Wahyudi Slamet , Lais Abu , Bintarto Redi 
Published: March 2021

Abstract
This study aims to know the effect of differences in grain size variation in fine and coarse bricks in the biogas purification process by reducing carbon dioxide gas levels using the adsorption method, so as to obtain the most suitable size to produce the most optimal purification results. In this research, the biogas purification process uses brick powder as an adsorbent, utilizing the alumina and silica content in bricks to absorb carbon dioxide gas. Testing the purified gas content in biogas using Gas Chromatography - Mass Spectrometry (GCMS). The data processing method used in this study was a factorial design method 23. The variations used in this study were the size of fine and coarse bricks, the purification time variation of 5 minutes and 20 minutes and the flow rate variation was 1 Liter minute−1 and 2 Liter minute−1. Fine size variation, a flow rate of 1 L Min−1 and a purification time of 20 minutes give the best results with the percentage level of carbon dioxide falling reaching 10.319%.