bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Android-based learning game on the concept of buffer solution
Authors: Helsy I , Subarkah C Z , Hermawati S 
Published: December 2019

Abstract
In the digital era it is now necessary to develop android-based learning media. Important buffer concept developed through android games because it includes abstract concepts, memorization and calculations. The research method used is the stages of developing the ADDIE model (analysis, design, development, implementation, and evaluation). This research only reaches the development stage which produces an Android-based learning game product. The results of the validation carried out on 3 expert lecturers, namely material experts, media experts, and learning experts showed that the Android-based buffer solution learning game is valid with a calculated value of 0.78. The results of a limited trial analysis of 10 students as respondents showed a percentage of 94.2%. Android characteristics that has an interesting visualization, practical and flexible and varied questions that students can develop their thinking skills by using android based learning media. Based on the results of the validation and trial, the Android-based learning game was declared feasible to be used as a learning medium on the concept of buffer solution.
The making of e-module based in inquiry on chemical bonding concept with representation ability oriented
Authors: Fauzi H , Farida I , Sukmawardani Y , Irwansyah F S 
Published: December 2019

Abstract
This study aims to produce teaching material products in the form of electronic modules with inquiry learning steps on the concept of chemical bond with representation ability oriented (macroscopic, submicroscopic, and symbolic) and find out the feasibility based on responses from experts and student respondents. The research method used is the Design Based Research (DBR) method with the ADD model covering the stages of analysis, design and development to be able to produce products in the form of electronic modules that are displayed in the form of text, images, animation, flash and video. Validation of the content and display aspects was carried out through consideration of three experts. In general, the results of the average value of the validation test in the form of rcount are between 0.77-0.81 so that the module is declared valid. Furthermore, the product was tested to 15 student respondents using a feasibility test instrument. The results of the feasibility test show that the percentage of feasibility in each aspect is in the range of 90-98% which agrees to all criteria. This shows an electronic module that has been made feasible to use.
Method validation for nitrate analysis in water using spectrophotometer visible with cadmium reduction
Authors: Nugraha W C , Ridwan Y S 
Published: December 2019

Abstract
The modified method for nitrate analysis in water sample by means of spectrophotometer visible using cadmium reduction has been validated. The method was validated according with analytical parameters. The result of this study were linear range 0,069-5 mg.L− 1, limit detection and quantitation were 0,025 mg.L−1 and 0,069 mg.L−1, respectively. repeatability of the method 2,19 % rsd and accuracy with 102,7 % recovery. Statistically, the results were in good agreement. The accuracy of this modified method has improved considerably in total. The method showed a good performance and can be applied for nitrate monitoring in water sample.
An effective alternative of pre-dawn meal using milk kefir
Authors: Listiawati M , Kurniati T , Windayani N 
Published: December 2019

Abstract
In this study, the nutritional composition of milk kefir cream and hunger resistance on its use as a menu of a pre-dawn meal were examined. The pre-experimental design of intact group comparison was used on 34 research subjects. The experimental group (n = 17) treated a pre-dawn meal using milk kefir cream and cereal while the control group used a regular predawn meal menu. The time of preparation, the implementation of the meal and hunger resistance were calculated and recorded. Based on the results of the study, in terms of methods, consuming 250 mL of milk kefir cream and cereal only takes about 7.9 minutes with a hunger resistance of up to 9.4 hours. With this composition and method, it is suggested that the results of this study can be useful to be an effective alternative of the pre-dawn meal both in Ramadan and other Sunnah fasting.
Computational study of inclusion complex between Omeprazole enantiomer and β-Cyclodextrin: NBO and RDG analysis
Authors: Ivansyah A L , Nurhidayah E S , Sundari C D D , Martoprawiro M A , Buchari B 
Published: December 2019

Abstract
In this study, it has been done NBO and RDG analysis of the R/S-Omeprazole and β-Cyclodextrin inclusion complexes by using density functional theory computational method, one-point calculation with the exchange-correlation functional of B3LYP and basis set of 6-31g (d). The results of the NBO analysis show that there are 7, 52, 5, and 44 of hydrogen bonds in the inclusion complex of β-Cyclodextrin and R-Omeprazole (1: 1), β-Cyclodextrin and R-Omeprazole (2: 1), β-Cyclodextrin and S-Omeprazole (1: 1), and β-Cyclodextrin and S-Omeprazole (2: 1), respectively. The results of the RDG analysis confirm that the R/S-Omeprazole inclusion complex with β-Cyclodextrin formed a Van der Waals interaction and also the effect of other than hydrogen bonds. However, the steric effect can be ignored because the amount is relatively small compared to hydrogen bonds and the Van der Waals interactions.
Application of the principle of hydraulic cranes on the conductivity tester
Authors: Farida I , Kheiriah R , Sari S , Irwansyah F S 
Published: December 2019

Abstract
This research is based on the idea that the need for an innovative experimental learning media in the study of electrolyte and non-electrolyte solutions. The innovative experimental learning media produced in this study is miniature cranes to test the electrical conductivity of electrolyte and non-electrolyte solutions. Crane equipment with hydraulic power is widely used to lift heavy loads at construction sites. The working principle of hydraulic cranes that utilizes the nature of the pressure of the liquid in the hydraulic pump according to Pascal’s Law. The working principle of the hydraulic pump has been applied to design a solution of electrical conductivity test equipment. The hydraulic system of a large device has been modified using tools and materials that are easily available in everyday life. The design of the electrical conductivity test equipment is composed of a hydraulic pump made from used injection hydraulic hose and hydraulic fluid. When the hydraulic pump is given pressure, the fluid (colored liquid) will continue the pressure through the hydraulic hose to the hydraulic working cylinder, so that the crane connected to the two electrodes can move. As a current source, Power bank circuits are used with a USB (Universal Serial Bus) cable and 5 Watt LED lights for conductivity indicators. Miniature props with hydraulic working principles are expected to provide new experiences in the electrical. Miniature props with hydraulic working principles are useful as innovative, interesting and learning media fun for students.
Product testing of recycled dried coconut leaf ash and olive oil for forehead makeup of Solo Putri style bride
Authors: Ambarwati N S S , Siregar J S , Amiruddin J , Ahmad I 
Published: December 2019

AbstractPidih is a cosmetic used on Javanese bride’s foreheads called paes. Peel material that is commonly used is wax which is colored as desired and has easy sticking properties. The aim of this research is to provide an alternative use of natural ingredients for pidih that used on the bride’s forehead makeup. Experiment was conducted to obtain black powder made from recycled dried coconut leaves and olive oil with the appropriate composition and then applied as paes in the Solo Putri style bride. The use of cosmetics with natural ingredients such as the leaves of the ash of dried coconut leaves added with olive oil with a ratio of 5 grams: 4 mL can produce black, shiny, easily painted on the forehead, and rather oily. The use of cosmetics in this material can be used as an alternative for pidih that is made of wax. Alternative pidih from the ash of dried coconut leaves can be used as a substitute for conventional pidih.
Kurzichalcolactone A and B, two chalcone derivatives from Indonesian Cryptocarya
Authors: Kurniadewi F , Nurjayadi M , Kartika I R , Hakim E H , Juliawaty L D , Syah Y M 
Published: December 2019

Abstract
Kurzichalcolactone A (1) and B (2), two chalcone derivatives were isolated from two species of Indonesian Cryptocarya: Cryptocarya phoebeopsis and Cryptocarya morotaiense. The structures of the isolated compounds were elucidated based on the analysis of spectroscopic data, including UV, IR, NMR, and mass spectra. On biological evaluation of these compounds for their cytotoxic activity, it was found that (1) exhibited moderate inhibition activities against murine leukemia P388 cells while (2) was inactive.
Antioxidant activity of Ethanol Extract, n-Hexane fraction, Ethyl Acetate fraction and Water fraction of Garut Orange Leaves (Citrus reticulata Blanco)
Authors: Fadhlillah F M , Oktaviani W , Mariani R 
Published: December 2019

Abstract
Antioxidants are compounds that are able to eliminate, cleanse, and resist radical effects. Antioxidants can stabilize free radicals by complementing the lack of electrons possessed by free radicals. Several studies have shown that citrus leaves of other species have been shown to have antioxidant activity. This study aims to determine the antioxidant activity of ethanol extract, n-hexane fraction, ethyl acetate fraction and water fraction of Garut orange leaves (Citrus reticulata Blanco) using DPPH (2,2-Diphenyl-1-Picrylhydrazyl) method. Garut orange leaves were extracted with ethanol 96% by macerator apparatus. Concentrated extracts were fractionated by liquid extraction method with n-hexane, ethyl acetate and water solvent. Furthermore, the ethanol extract, n-hexane fraction, ethyl acetate fraction and water fraction of Garut orange leaves were tested for antioxidant activity using the DPPH (2,2-Diphenyl-1-Picrylhydrazyl) method. The antioxidant activity test results showed that ethanol extract of Garut orange leaves had better antioxidant activity with IC50 value of 42.925 ppm, followed by n-hexane fraction with IC50 value 46.156 ppm, ethyl acetate fraction with IC50 value 49.371 ppm and water fraction with IC50 55.662 ppm.
Improving the quality fruit of Citrus cv. Siam out off-season through the application of fertilization and pruning
Authors: Astiari N K A , Sulistiawati N P A , Mahardika I B K , Rai I N 
Published: December 2019

Abstract
This study aims to determine the efforts to improve the quality of Siamese citrus fruits during the growing season through fertilization and pruning. This experiment used a factorial randomized block design consisting of 2 factors. The first factor is fertilization, namely: P0 (manure/control), P1 (manure, N, P, K, and Ca) and P2 (manure, N, P, K, Ca, Zn and Cu). While the second treatment is pruning, namely: M0 (without trimming), M1 (trimmed young shoots) and M2 (trimmed young shoots, twigs, and leaves affected by disease and shaded). The results showed that the interaction between fertilization and pruning treatment had no significant effect on all observed variables. P2 treatment can improve fruit quality, which is reflected by the weight of the fruit harvest per tree (3442.76g); weight per fruit (173.58g) and total dissolved solids (9.48°brix) or increase by 99.79%; 35.69% and 30.22% compared to P0 which is 1673.13g; 127.92g and 7.28°brix. In the M2 treatment can improve fruit quality, which is reflected by the weight of fruit harvest per tree (3638.77g), weight per fruit (173.58 g) and total dissolved solids (9.63°brix) or increase by 40.91%; 19.56% and 25.55% when compared with treatment M0 which is 2582.34g; 145.92g and 7.67°brix.
CO2 MMP determination on L Reservoir by using CMG simulation and correlations
Authors: Ginting M , Wijayanti P , Cindra R A 
Published: December 2019

Abstract
CO2 minimum miscibility pressure (MMP) is an important parameter in CO2 enhanced oil recovery (CO2-EOR) process. The CO2 injection must be conducted at the pressure equal or greater than MMP. The aim of this study is to determine CO2 MMP by using one-dimensional CMG simulation model and CO2 MMP correlations on L reservoir. To make an accurate simulation model and to choose the most satisfying correlation, it is necessary to validate by comparing the obtained CO2 MMP with experiments in the laboratory on eight type oil from various fields. The result showed that Zhang’s correlation is the best correlation which have -13.9% average percentage of errors while using the CMG simulation model shows the average percentage errors approximately -6.5 %. Using Zhang’s correlation, CO2 MMP on L reservoir is about 3166 psia and from CMG simulation, CO2 MMP equals to 3219 psia.
Laboratory studies of sand problem prevention using Mechanical Methods and Gravelpack design performance analysis in Field X
Authors: Priatmoko A Y , Kasmungin S , Setiati R 
Published: December 2019

Abstract
Sand problem is one problem that can disrupt oil well production. With the sand problem, the productivity of the well decreases so that there will be a decrease in oil production. Sand problems that occur result in increased production loss and cost lost. The purpose of this research is to find the right solution in overcoming sand problem, by studying the characteristics of the rock. Laboratory experiments were carried out using a mechanical method approach which was then used to determine the appropriate gravelpack design. The steps taken include testing the strength of the core of the three zones, the decrease of strength can conclude that the core of the three zones has begun to weaken. The results of the analysis of the grain size of the D50 then used to determine the appropriate gravelpack design in each zone. Zone A, using gravelpack 60/80, zone B using gravelpack 16/20, and zone C using gravelpack 30/50. From the gravelpack design obtained then a sand retention test is performed to determine the gravelpack’s performance. With the results of the sand retention test showing good gravelpack performance for each zone, where the permeability value is good and the solid produced is not too much.
Corrosion assessment of a leakage pipeline in the seabed: A case study
Authors: Fatah M C , Diaz A , Darwin A 
Published: December 2019

Abstract
A pipeline in the seabed was successfully commissioned and had commenced production from the well. The pipeline has life time design for 20 years. However, a leakage from the flange connection was detected a couple months after start of production. The pipeline was isolated by closing the valves on the line tee, and shutdown the well production. This condition remains for 6 months before any remedial action was taken. During that period, it is believed that there is any corrosion mechanism occurred which might reduce the pipeline integrity. The paper briefly described the corrosion threats and assessed the corrosion rate of the leakage pipeline with limited information of factors that affecting corrosion rate. Additionally, recommendations for preparation of the pipeline to minimize internal risks are given.
Non-empirical study on pressure dependence of ruby bond length
Authors: Novita M , Cholifah N , Ogasawara K 
Published: December 2019

AbstractDue to its potential application in luminescence technologies, the complete understanding on pressure dependence of ruby is especially important. Up to recently, the theoretical prediction on the structural properties of ruby under pressure has been made involving the empirical parameters. Therefore, here we performed a non-empirical study on the pressure dependence of ruby bond length. Due to the Cr3+substitution and the applied external pressure, the local structure of α-Al2O3: Cr3+was changed. We estimated this effect by performing the first-principles band-structure calculations using Cambridge Serial Total Energy Package (CASTEP) method and compared with the Shannon’s crystal radii method. The two different bond lengths; Cr-1stnearest neighbour oxygen (d1) and Cr-2ndnearest neighbour oxygen (d2) were investigated in detail. The results show that under 0-110 GPa thed1andd2decreased ca. 0.172 and 0.145 Å, respectively. These results were slightly smaller than thed1andd2decreases in the case of pure α-Al2O3crystal, they were observed to be ca. 0.167 Å ford1and 0.177 Å ford2. In the other words, thed1-d2differences were larger at the higher pressure, ca. 0.052-0.080 Å for 0-110 GPa.
The effects of substrate on enhancement of UV emission of ZnO nanorods
Authors: Sugihartono I , Silmina A D , Fahdiran R , Isnaeni I 
Published: December 2019

Abstract
We have synthesized ZnO nanorods by hydrothermal at 95 °C for two hours on different substrates i.e. glass, ZnO, and ITO. Morphologically, the average diameter of ZnO nanorods on glass, ZnO, ITO are 117.6 µm, 133 µm, 98.4 µm, respectively. According to the international center for diffraction data (ICDD) number #01-079-0207, the ZnO nanorods on all substrates possess a polycrystalline wurtzite structure. By full width at half maximum (FWHM) of ZnO NRs in (002) plane, we have determined crystallite size and micro-strain using Scherer’s equation and Stokes-Wilson equation, respectively. The crystallite size and micro-strain of ZnO NRs vary with different kind of substrates. Optically, ZnO nanorods on a glass substrate have the strongest excitonic-related ultraviolet (UV) emission. Further observation, we have determined the UV/GB ratio to confirm the crystalline quality of ZnO NRs on glass, ZnO, and ITO substrates. These UV/GB ratios are 101.35, 68.14, and 22.74. It is indicating the ZnO NRs on glass has a better crystalline quality which indicates fewer native defects concentration compared to the others.
Influence of layer thickness and 3D printing direction on tensile properties of ABS material
Authors: Dwiyati S T , Kholil A , Riyadi R , Putra S E 
Published: December 2019

Abstract
The 3D printing process is a kind of additive manufacturing, that the basic principle of this process is adding material layer by layer to form a product. The purpose of this research was to study tensile properties of 3D printing ABS (Acrylonitrile Butadiene Styrene) material with axial and lateral direction. The specimen was printed according to ASTM D 632-02 by layer thickness variation around 0.1 mm, 0.2 mm and 0.3 mm. Moreover, three specimens were made for each printing axial and lateral direction. Tensile test was performed using Zwick Roell Series Z 021 machine. Then, the fracture surface was studied by SEM testing used ZEOL JSM-6510LA. Based on the research from 6 variation layer of 3D printing, the optimal result was found on the axial direction of 0.3 mm thickness layer with tensile strength 30.60 MPa and able to receive maximum load 551.13 N. The lateral direction of 0.3 mm thickness layer has tensile strength 19.42 MPa and able to receive maximum load 349.12 N. The voids were seen at the fracture surface of specimen.
Effect of reduced graphene oxide addition on the performance of zinc oxide nanorod based dye-sensitized solar cell
Authors: Wahab M S , Madsuha A F , Rosa E S , Yuwono A H 
Published: December 2019

Abstract
As one of third generation photovoltaic device, dye-sensitized solar cell (DSSC) plays important part in search for new and renewable energy resources. As part of this device, dye has a very critical function due to its responsibility in absorbing the photon energy from the sunlight. The more light can be absorbed, the higher the value of photon to electricity conversion efficiency can be obtained. For increasing the absorption capacity of the dye, this work investigated the effect of reduced graphene oxide (rGO) addition into the dye solution with rGO to dye weight % ratio of 1:100; 3:100; and 5:100 respectively. On the basis of investigation, it was found that the ratio of 3:100 produced a higher power conversion efficiency (PCE) of about 0,02% as compared to the reference cells which displayed a value of 0,005%. It confirms that introducing rGO into the dye can enhance the DSSC performance, though several fabrication handling procedures still need to be improved as well.
Modification of the Maxwell model for calculation of stress relaxation and creep behavior for polyester yarns
Authors: Rosyidan C , Maulani M , Samura L , Putra V G V 
Published: December 2019

Abstract
Textile materials, especially yarns formed from polymers such as polyester during deformation, have viscoelastic properties, namely a combination of elastic and viscous properties. Several studies have been conducted to model viscoelastic on textile materials, especially yarns. In this study, modelling is done by fitting data through experiments which are then modelled with a theory of the modification of the Maxwell model as a reference in making predictions through the data fitting method. The results of the data fitting prediction in the form of exponential curves have a regression value that approaches the experimental curve (R
2 = 0.999 and 0.999).
Temperature and additive coconut shell charcoal effect on density and porosity of ceramic membrane based on zeolite and clay
Authors: Budi A S , Budi E , Mujadi M 
Published: December 2019

Abstract
Temperature and additive coconut shell charcoal effect on density and porosity of ceramic membrane based on zeolite and clay have been analysed. By the addition of the additive in the form of charcoal can lower the density of the ceramic membrane. It can also increase the porosity of the zeolite membrane-based ceramic and clay. From scanning electron microscopy (SEM) images can be seen that the largest pore size owned by the sample that contains 80% zeolite and 10% additives. As for the large number of pores generated depends on how much the content of additives contained in the sample. There is a tendency with the rising temperatures and a growing number of additives contained in the sample, the more the pores generated.
Expected likelihood based query for active learning of Gaussian mixture models based classifiers
Authors: Iswanto B H 
Published: December 2019

Abstract
Typically, a supervised machine learning requires sufficient labelled data to achieve satisfying performance. In many domains, however, the labelled data are often expensive to obtain and requires laborious human effort. In order to minimize the labelled data, we propose an active learning method by introducing the expected likelihood as a criterion in the query system, especially for the Gaussian mixture models based classifiers. In this scenario, the expected log-likelihood is calculated for all unlabelled examples in a pool data set, then an instant with the lowest value is chosen to query the object of the label. Experiments were performed to evaluate the effectiveness of the method. Empirically, using the two class artificial data set we observed that the proposed method can reduce significantly the number of labelled examples required to achieve a certain performance compared with passive learning.