bluuebunny/crossref_metadata_2025 huggingface dataset:
Screening of biosurfactant producing bacteria from hydrocarbon contaminated soil
Authors: Kurniati T H , Rahayu S , Sukmawati D , Maharani W
Published: December 2019

Biosurfactants are surface-active molecule produced by microorganisms and have several advantages over the chemical surfactants. The objective of this research was to obtain biosurfactant-producing bacteria from hydrocarbon contaminated soils in Jakarta Bay and to observe their biosurfactant activity through emulsification capacity and surface tension reduction capability. Overall, 19 isolates were screened for biosurfactant production by hemolysis assay, drop collapse assay and oil spreading assay. The result showed that 13 strains gave positive results on the screening tests and were determined as biosurfactant-producing bacteria. Three strains (TKY 3, TKY 14 and TKY 19) had the best biosurfactant activity. The lowest surface tension value was achieved by two strains (TKY 19 and TKY 14) with the same value of 37,84±1,45 mN/m.
Application of biochar and compost to changes in physical and chemical properties of soil and corn yield on dry land
Authors: Putra I G L A A A , Situmeang Y P , Yuliartini M S , Udayana I G B
Published: December 2019

The purpose of this study was to determine the effect of biochar and compost fertilizer and their interactions on changes in the physical and chemical properties of soil and corn products on dry land. This experiment uses a randomized block design with factorial patterns. The first factor, the biochar dose consisted of 4 levels, namely: 0; 5; 10; and 15 tons ha−1. The second factor, compost dosage consisted of 2 levels: 0 tons ha−1 and 20 tons ha−1. The highest dry corn seed per ha was obtained from the treatment of 10 tons ha−1 biochar which was 9.21 tons which increased 35.56% compared to dry corn seeds per ha which were obtained from the treatment without biochar which was 6.79 tons. The treatment of compost doses of 20 tons ha−1 gave the highest value of dry corn seeds per ha, which was 8.73 tons, an increase of 16.58% compared to the lowest yield, which was 7.49 tons in the treatment without compost. The interaction between the treatment of biochar and compost dosages had no significant effect on all observed variables, except for organic C, available P, available K, and very significant CEC effect.
Phytochemical test on herbal drinks loloh cemcem at Penglipuran Village, Bali
Authors: Cahyawati P N , Lestari A , Subrata T , Dewi N W E S , Wiadnyana I G P
Published: December 2019

Loloh is a traditional Balinese drink that is believed to be able to overcome certain diseases. The Balinese people make loloh independently for self-consumption or trading in the small-scale home industry. The making of loloh is usually passed down from generation to generation, but until now has not been standardized. Loloh cemcem is one of the traditional drinks from The Penglipuran Village, Bangli Regency, Bali. This study aims to conduct phytochemical tests on loloh cemcem in Bali, especially from Penglipuran Village. Phytochemical tests include levels of alkaloids, steroids, terpenoids, phenolics, saponins, flavonoids, steroid, and tannins. The results of this study indicate that loloh cemcem produced in Penglipuran Village contains flavonoids, terpenoids, tannins, phenols, and alkaloids. But do not contain saponins and steroids. Loloh cemcem has the potential to be an antibacterial, antioxidant and another benefit that still needs further investigation.
Smartphones application in alkali metal flame tests
Authors: Sari S , Magfiroh E , Irwansyah F S , Farida I , Sobandi O
Published: December 2019

The purpose of this study is to determine alkali metal content by means of flame using smartphone application with experiment. Method stages are performed by making a standard solution and test solution first. Standard solution for determining density line equations to vector norm value. While the test solution is to determine the known concentration of NaCl from the line equations. The standard solutions of each RGB value is tested to get an equation with the value R2 must be close to or equal to 1. The analysis shows that the use values of RGB obtained from a captured image of the video is the color intensity resulting from the flame sodium metal. Level of the standard solution 1 shows result that is quite accurate with test solution levels of 0.0313 g/mL. Likewise with standard solution 2, the result is 0.0063 g/mL and standard solution 3 is 0.00032 g/mL. The value of R2 of the standard solutions must have a value close to or equal to 1. This is because the value of R2 affects the concentration results obtained. If R2 has a value that is very close to 1, an accurate result will be obtained.
The making electronic modules visualization chemical equilibrium process based on predict-oberve-explain
Authors: Sahara R , Subarkah C Z , Rahmatullah S
Published: December 2019

This study aims to create an e-module visualization chemical equilibrium processes based on POE (Predict-Observe-Explain) which includes sub-concepts of dynamic equilibrium, homogeneous and heterogeneous equilibrium, and factors that influence chemical equilibrium. The three main activities in this e-module are predicting, observing and explaining. The e-module was created using the Design Based Research method with ADD design (Analysis, Design, Development) which was validated by two material expert lecturers and two multimedia expert lecturers producing an overall average calculation of 0.87 while the results of the feasibility test conducted at ten students show a percentage of 98.11%. This shows that this e-module is very feasible to be used as teaching material.
Challenges and opportunities of green chemistry concepts in the Synthesis of Sodium Lignosulfonate (SLS) surfactant
Authors: Setiati R , Siregar S , Marhaendrajana T , Wahyuningrum D , Listyani A
Published: December 2019

Green chemical is the designing of products and processes that minimize the use and generation of hazardous substances. Synthesis of Sodium Lignosulfonate (SLS) Surfactant can be processed from bagasse, waste of sugar cane. The aim of this study was to show that sodium lignosulfonate surfactant (SLS) can be made from bagasse using the Microwave-Assisted Organic Synthesis (MAOS) with the concept of green chemistry. Bagasse processing becomes SLS with hydrolysis and sulfonation process using microwave radiation. The process is closed system, for 1 hour, with a microwave power of 300 watts at 80oC. The process is using Microwave Assisted Organic Synthesis (MAOS) which is equipped with chemical flask and condenser. Reagents are used in small concentrations, 2% NaOH and 0.1 M sodium bisulfite. The result of synthesized SLS from bagasse is brown powder. The synthesized SLS product using Green Chemical concepts has been tested with Fourier Transform Infra Red (FTIR) consisting of Alkene, Sulfonate, Carboxylic Acids and Ester. This composition is similar to the composition of the commercial SLS standard which petroleum based, using as surfactant injection in the EOR process. The Green Chemical concept has the challenge and opportunity of synthesizing Sodium Lignosulfonate Surfactant using Microwave Assisted Organic Synthesis.
Cytotoxic sesquterpenoid compound from the stembark of Aglaia simplicifolia (Meliaceae)
Authors: Kurniasih N , Supriadin A , Fajar M , Abdulah R , Harneti D , Supratman U , Taib M N A B M
Published: December 2019

Previous phytochemical studies from the Aglaia genus reported the presence of terpenoid compound. This research describes the isolation and structure elucidation of sesquiterpend compound from the stembark of Aglaia simplicifolia. Dried stembark of A. simplicifolia extracted with methanol and then partitioned with n-hexane, ethyl acetate, and n-butanol, respectively. The n-hexane extract then was separated and purified with chromatography techniques to obtain isolated compound. The chemical structure of isolated compound was elucidated by IR, NMR 1D, NMR 2D as well as mass spectra and by comparison with those previously reported spectra data. The compound identified as senecrassidiol. This compound showed cytotoxicity activity against HeLa cervical cancer cells with IC50 values of 2.18 µM.
Antioxidant activity of volatile compounds from Syzygium aromaticum (L.) leaves
Authors: Alawiyah A L , Senania A , Sari H , Perdana F , Musthafa I
Published: December 2019

Syzygium aromaticum (L.) leaf essential oil have been identified as antioxidants. This study aimed to determine the volatile compounds and antioxidant activities of Syzygium aromaticum (L.) leaf essential oil. Syzygium aromaticum (L.) leaves were extracted by steam distillation. The identification of volatile compounds was done by Gas Chromatography Mass Spectroscopy (GC-MS). DPPH test was used to evaluate the sample’s antioxidant activity. The results provide information that the extract have 15 of volatile compounds from Syzygium aromaticum (L.) leaf essential oil. Moreover, DPPH test has identified a very strong antioxidant by IC50 values was 8.224 µg/mL.
Titration pre-lab demonstration videos in basic chemistry laboratory activity: Design and development
Authors: Fitriani E , Paristiowati M , Mukarromatunnisa B
Published: December 2019

There are difficulties for first-year chemistry students to adapt to chemistry laboratory activities due to their lack of experience in their schools. As a result, it affects their confidence and also their safety awareness in the laboratory. One of the very basic required skills in a chemistry laboratory is undertaking titration. This multi-year study aims to design and develop chemistry pre-laboratory demonstration videos to make students familiar with the required laboratory skills before they start laboratory activities. The data were collected by paper-based and online questionnaires, observation, and inverview. According to the evaluation by users and experts, the usability and feasibility of the videos were categorized as very high. Moreover, corrections and suggestions were implemented to improve the quality of the videos.
Using Android-based learning game on the concept of buffer solution
Authors: Helsy I , Subarkah C Z , Hermawati S
Published: December 2019

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

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

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

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

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

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

Pidih 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

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

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

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

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

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

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

Due 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

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

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

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

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

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

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.
Fourier transform for feature extraction of Electro Encephalo Graph (EEG) signals
Authors: Hindarto H , Muntasa A , Sumarno S
Published: December 2019

Electro Encephalo Graph (EEG) is a device that can capture electrical activity in the brain and inform the mind’s condition such as emotional, fatigue, alertness, health and concentration level. Modelling the EEG signal before classification needs to be done, several studies have been carried out using Wavelet, Power Spectral, or Autoregressive transformations as feature extraction. This study explains the application of K-Nearest Neighbour as a classification and Fourier transform by taking the value of Power Spectral for feature extraction from the wave signal Electro Encephalo Graph (EEG). This study aims to identify EEG signals used for cursor movements. The data used are EEG data originating from the 2003 BCI competition (BCI 2003 Competition). The data contains data class 0 (for movement of the cursor up) and class 1 (for movement of the cursor down). Decision making is done in two stages. In the first stage, the Power Spectral value for each EEG signal is used to extract the feature. The feature is input to K-Nearest Neighbour. In the second stage of the identification process into two classes (class 0 and class 1) EEG signal data files, there are 250 EEG signal file training data and 25 from EEG signal file testing data, so that the total becomes 300 EEG signal data files. The results obtained for the classification of EEG signals are 84 % of the signal data tested.
Study of image reconstructions of Indonesian traffic sign using Criminisi and Hung method
Authors: Asmara R A , Lazim F , Rahutomo F , Ariyanto R , Rahmad C , Nurhasan U , Muhiqqin I
Published: December 2019

Image reconstruction of traffic signs serves in order to improve the image quality of traffic signs that are covered leaves, tree branches or pole so that it can facilitate the process of recognize or detecting traffic signs. Inpainting is one of the image restoration methods to reconstruct images that have been damaged or the removal of unwanted objects where the area to be restored is based on information around the area. Criminisi introduces an inpainting method with an exemplar-based approach that combines the structure-oriented and texture-oriented scheme. While Hung popularized the Criminisi method and combined it with contour construction (Bezier curve). The researcher tried to compare the two methods by using a number of images of traffic signs, one of them by using images with a size of 400 x 407 pixels, issuing the results of Peak Signal to Noise Ratio (PSNR), the Criminisi method gets results from PSNR 36,479 decibel (dB), while the Hung method gets results from PSNR 36,827 dB. This means the result of Hung method is more similar to original image than Criminisi method.
Mobile learning in promoting student’s engagement
Authors: Purwanti Y , Imania K A N , Rahadian D , Bariah S H , Muljanto S
Published: December 2019

Students engagement is an important element in learning. Mobile learning is a learning media that can’t facilitate student’s engagement. The purpose in this study is to measure student’s engagement in problem solving behavior abilities; explanation; and analysis using mobile learning. In this research we used a qualitative research method with a case study approach combined with a literature study. Library studies are needed before or together with case study with the intention that when observers encounter difficulties in the field, they can refer to the theories that have been studied. Or you can compare truth from theory with real events in the field. The field survey was conducted as a first step to find out student involvement especially in 1) problem solving ability, 2) explain or re-express material in the student’s language style, 3) analyze material. With field surveys, we will get a clear picture of how the learning simulation uses the student’s involvement. The engagement of students shows a sufficient tendency to solve problem, explain learning material and analyze.
The 3D simulation of Lorentz Force based on augmented reality technology
Authors: Bakri F , Sumardani D , Muliyati D
Published: December 2019

The Lorentz force concept is classified as an abstract to be understood. The direction of the current, the direction of the magnetic field and the direction of the force generated are difficult to understand without real media. This article will describe the Lorentz Force style simulation by utilizing augmented reality technology. The development of Lorentz force media uses 4D stages (define, design, develop, and disseminate). Interactive media based on augmented reality Lorentz force can display the Lorentz style concept by making changes to magnetic field variables and electric currents. The process of developing this media has been guided by pedagogical content knowledge (PCK). Our simulation successfully displays the relationship between the magnetic field and electric current which is directly proportional to the Lorentz force. AR-based Lorentz force simulation has fulfilled the principle of technological pedagogical content knowledge (TPACK).
Puzzle game solving with breadth first search algorithm
Authors: Rahim R , Dijaya R , Multazam M T , GS A Daengs , Sudrajat D
Published: December 2019

Today’s games have been played by many people from young to old age. There are many types of games, one of which is a puzzle game. Puzzles, which are brain teasers that challenge the skills of their players, never seem to lose their popularity and are never consumed by age. Puzzle is one type of game that is enough to squeeze the brain to solve it. The solution that can be used to simplify problem solving is to apply a search algorithm that is used to check the initial state to the final state and provide the most optimal solution for completing the puzzle, the purpose of this study were using algorithm used to solve these problems using the Breadth First Search algorithm. The use of the Breadth First Search algorithm in solving puzzle games can make it easier for users to get the best solution in the form of completion steps and also the possibility of solving various conditions based on the puzzle conditions that you want to solve.
Model of knowledge portal system for higher education: Literature review
Authors: Syaripudin U , Rahman T K A , Ramdhani M A
Published: December 2019

This study presents a discussion of the Tridharma-based university knowledge portal model (education, research, and community service). This study aims to ensure that lecturers activities are in accordance with the Tridharma of higher education and national standards of higher education. The analytical method used is the literature review, with the object of research being hypothetical colleges in the form of universities. Based on the results of the identification of university needs, the knowledge portal model is required to have the ability to develop lecturer competencies in accordance with the Tridharma of higher education. Knowledge portal is designed to have the ability to manage knowledge well, by providing facilities: information gathering, information categorization, information distribution, information collaboration, information retrieval, and knowledge sharing.
Combination Base64 and GOST algorithm for security process
Authors: Rahim R , Sumarno S , Multazam M T , Thamrin S , Sumantri S H
Published: December 2019

Cryptography in various communications both online and offline is very necessary and generally cryptography is used to secure data in the form of text while non-text data requires special algorithms. Base64 is an encoding algorithm that can convert non-text data into binary data so that the data can be secured with cryptographic algorithms such as the GOST algorithm. The combination of the BASE64 and GOST algorithms is expected to be able to secure all types of data that exist and have the ease of returning to their original form without damaging the original data, besides this combination will increase data security because the combination of these two algorithms produces ciphertext that is difficult to know if the process is done cryptanalyst by third parties. The results of the combination of Base64 and GOST algorithms are expected to be able to deliver dynamic security contributions to various existing data objects so that they can be used both online and offline.
Sleep disorder diagnosis expert system using certainty factor method
Authors: Abidin R J , Kaffah F M , Khaerunisa P , Dauni P , Saputra M I N
Published: December 2019

Sleep disorders is a disorder experienced by a person when the REM and NREM cycle don’t work normally. Prolonged sleep disorders can cause a variety of bad conditions such as depression, fatigue, reduce work, performance and endurance. It quickly offended till affect to our own safety. The latest study in 2018 conducted by Dr. Welly Sondakh, MPH in Jakarta revealed that there were 10% of people with insomnia from the Indonesian population or around 28 million people. The low public awareness of sleep disorders causes them to need alternative media, namely an expert system to diagnose sleep disorders. Expert system is a system that uses the knowledge of an expert to solve a problem in a particular field where the system is not limited by time and can be used by many people. The method used in this system is Certainty Factor as an inference engine to determine the results of the diagnosis based on the symptoms determined. The calculation of this method combines the MB (measure of increased belief) and MD (measure of increased disbelief) values obtained from experts. From 50 test data, 45 data were obtained so that the accuracy level reached 90%. This shows that the expert system of diagnosing sleep disorders is suitable for early diagnosis of sleep disorders.
Local wisdom-based e-encyclopedia as a science learning medium in elementary school
Authors: Kumala F N , Setiawan D A
Published: December 2019

The number of online encyclopedias is still limited and generally, they are not too interesting to be read by students since they tend to load information about unfamiliar animals for students. This paper seeks to describe the use of local wisdom based electronic encyclopedia as a learning media in the Science subject in Elementary school. This research was conducted on elementary school students in the city of Malang with 82 people using data collection instruments. Such as questionnaires and observation sheets. The research was carried out through several stages, namely the analysis stage, production stages, product design and evaluation stage. The finding show that local wisdom-based animal based e- encyclopedia are good in terms of content, presentation, language and the use of online encyclopedia triggers students to be more motivated and enthusiastic to learn during the learning process. The familiar contents and concepts given made a more meaningful learning process for students.
Synchronization of learning management systems with store-and-forward communication using ship to support e-Learning at rural islands
Authors: Sambul A M , Jacobus A , Ruindungan D , Riyaldi A
Published: December 2019

One of the challenges for the people who live in the rural islands of the developing countries is the lack of access to education. Although ICT (Information and Communication Technology) is increasingly regarded as an essential tool to support learning activities in rural areas, the availability of telecommunication infrastructure in such areas is still problematic, primarily because of high implementation cost and low revenue. This study aimed to develop an e-Learning model for the community in the rural islands which utilize ship to deliver to and receive data from the island using store-and-forward communication technique over a transient long-range wireless link established when the ship is at a certain distance from the island. Here we focused on the design of a synchronization method between databases of multiple learning management systems (LMS) between the ship and the island. The design has been implemented and tested using Moodle installed on low-power Raspberry Pi computers. The result showed that our design is suitable to be used in such requirements, hence making it a feasible solution to support ICT-based learning for the people in rural islands.
Fuzzy string implementation matching on android-based encyclopedia and anatomy quiz
Authors: Firdaus M , Mud’is M H , Nurjaman I , Fauzia I , Busro B
Published: December 2019

Encyclopedia anatomy is an android application to introduce anatomy, equipped with a search feature, multiple choice quizzes and guess image quizzes. Due to some anatomical term is uptake from foreign languages and frequently typing errors by a smartphone user, then search feature in this application implement fuzzy string matching method which uses Levenshtein distance algorithm. However, the results obtained are still not accurate, then added method of splitting and indexing, so the results are more accurate and search process fast enough. Due to more simple than a book and supported by a good appearance, this application can get a positive response from the users.
Implementation of Kansei Engineering on academic information system interface design based on Android
Authors: Mud’is M H , Busro B , Faizin B , Ali H
Published: December 2019

One of the goals of the Android Application is to improve the quality of the Academic Information System. This study uses the Kansei Engineering method where the emotional power of users is involved in getting design material that has a strong influence on the Android Application design concept. This study used 17 Kansei Word and 12 specimens as samples of Android applications. Kansei Word is selected from words related to an Android Application display. While specimen samples or Android applications are selected based on different characteristics between Android applications with each other. This study involved 35 participants. To describe the emotion concept to the E-Learning specimen structure, where there are several relationships between variables, multivariate statistical analysis is carried out by involving the Coefficient Correlation Analysis (CCA), Principal Component Analysis (PCA) and Factor Analysis (FA). The results of the CCA analysis of all participants; it can be seen that the emotional correlation between Kansei Word has two relationships, namely strong relationships and weak relationships. Strong relationships are characterized by high values rather than other Kansei Word values.
The 3-D animation of radiation concept using augmented reality technology
Authors: Bakri F , Kencana H P , Permana H , Muliyati D
Published: December 2019

Radiation concept in Nuclear subject in Physics Learning include some devices, such as Geiger Muller counter, Wilson cloud chamber, scintillation detector. This research aims to visualize the radiation concept from that device using augmented reality technology. The result shows the 3-D animation can: describe the mechanism of the Geiger Muller counter detector to detect radiation; describe the mechanism of Wilsons fog chamber detects radiation; and describe the mechanism of the scintillation detector tool to detect radiation. All the markers developed to get a decent value to be used as a medium for learning physics about radiation concept.