bluuebunny/crossref_metadata_2025 huggingface dataset:
Re-design tony kart mitox gokart model (Re-design analysis of chain-drive components)
Authors: Mubarak I
Published: December 2019

The purpose of this study was to determine the type of chain suitable for use on karts, besides that this study aimed to determine the safety factors of chain hinges and sprocket gears used in redesigned karts. The method used in this study uses descriptive analysis method, namely by describing the data about the chain wheel on karts, after describing the data, the data are analyzed theoretically about the forces that occur in the chain wheel and the safety of the use of chain wheels used in redesigned kart After analysing the data, it was found that the chain wheels on the redesigned karts were safe to use. This is indicated by the acquisition of a hinge safety factor value of 4.02. The results of this study have an impact on the use of chain wheels on the redesigned karts in the safe category to be used for kart racing purposes.
An experimental investigation on the effects of mineral oil flow rate on CPU immersion cooling
Authors: Kristian S N , Wibowo K M , Pambudi N A , Harjanto B , Bugis H , Biddinika M K , Kuncoro I W , Hijriawan M
Published: December 2019

The aim of this research is to analyze the effect of using immersion cooling with different flow rate and fan rotation on decreasing the temperature on CPU. The study used three variables of flow rate: 0.5, 1 and 1.5lpm. in addition, three other variables of fan rotation, 400, 600, and 800 rpm, were used as well. Data collection was by means of benchmark software to load the CPU to work maximum and the logging software to record the temperature. The results show that the immersion cooling could potentially be utilized as the new and more effective cooling system. The most optimum variable to decrease the temperature was 1, 5 lpm with fan rotation at 800 rpm. It decreased the maximum temperature from 60 °C to 47 °C, a deviation of 13 °C lower compared to the conventional fan cooling system with air as a medium. The study established that the higher the flow rate and the fan rotation, the higher temperature can be decrease. Therefore, immersion cooling can be the solution to decrease the consumption of energy on IT sector on a bigger scale.
Public knowledge in changes of fossil fuel become biofuel on the transportation sector
Authors: Untari R , Pambudi N A , Biddinika M K , Harjanto B
Published: December 2019

The government of Indonesia through vision energy 25/25 saves energy by saving fossil fuels. One sector that consume the largest fossil fuel is transportation. Through the vision, this sector has a great opportunity to make savings by converting fossil fuels into biofuels as stipulated in the mandatory B20 policy. The success of the implementation of the policies depends on providing socialization to the public. Therefore, the objective of this study is to collect the information about the level of knowledge of the community in receiving information about the use of biofuels in the transportation sector. This is a quantitative study using a questionnaire in data collection, finding that people’s understanding of biofuels, including the perception and information of biofuels, still needs to be improved. The results of the study can be used to assist in the planning, implementation and evaluation of policies made by the government in the use of biofuels in the transportation sector in Indonesia. The implications of this study are as a material consideration for increasing the dissemination of information to the public about biofuels, so that the use of biofuels can increase.
Structural, optical, and room temperature dielectric properties of La1-xAxFeO3 (A = Mg, Sr, and Ba) perovskite nanomaterials
Authors: Masta N , Rafsanjani R A , Triyono D
Published: December 2019

This paper investigated the variation of structure, optical and electrical properties of LMFO, LSFO, and LBFO. All samples were synthesized by sol gel method. For this present research study, the structure of the material was investigated by X-Ray Diffraction (XRD). Nevertheless, the electrical properties of this materials were investigated by using RLC Meter. The optical band gap energy was obtained by using UV-Vis Spectroscopy. The optical gap energy evaluated by Kubelka Munk method are 1,58 eV, 1,32 eV and 1,38 eV for LMFO, LSFO and LBFO respectively. Therefore, this small gap energy impacted sensitivity of the material towards its optical properties. To sum up, this what makes all samples are the suitable candidates for alcohol gas sensor.
Analysis of Uranyl Nitrate Hexahydrate composition for optimum neutron multiplication factor of SAMOP
Authors: Wahyono P I , Syarip S
Published: December 2019

Subcritical Assembly for Molybdenum Production (SAMOP) is a concept of nuclear reactor where the neutron multiplication factor (keff) less than one (keff ∼ 0.99). Therefore, SAMOP reactor need an external neutron source for its operation. Uranyl Nitrate Hexahydrate, UO2(NO3)2 or UN is used as fuel as well as target material for 99Mo production. The 99Mo isotope is used to generate 99mTc which is the most widely used radioisotopes for diagnostic in nuclear medical fields. The composition of Uranyl Nitrate Hexahydrate (UNH) should be analyzed to achieve the required subcritical level in the SAMOP core i.e. k-eff ∼ 0.99. Methodology for this analysis is an elemental composition calculation of UNH, with enrichment of uranium of 19.75% and 2.81 gr/cc of density. The analysis result shows that the elemental composition of 235U, 238U, N, O, and H, are 4.9715%, 20.2009%, 5.3448%, 37.4138%, and 32.069% respectively, and therefore, the composition of U and N-O-H are 25.1724%, and 74.8276% respectively. The composition is then used as input for the neutronic analysis using the WIMS-D/4 computer code for keff calculation of SAMOP. The result shows that the optimum keff of 0.99 is achieved with the above elemental compositions.
Microstructural and electrical properties of human blood
Authors: Handoko E , Budi S , Fahdiran R , Saptari S A , Humairrah A , Mutmainnah Z , Puspitaningrum R , Alaydrus M
Published: December 2019

Human blood has been prepared from healthy human body. Structure, and electrical properties of human blood are studied. Scanning electron microscope (SEM) image exhibits a uniform size distribution of thrombocyte of human blood with an average size less than 15 μm. Electrical analysis of the blood sample was measured by linear sweep voltammetry in the potential range between -1 and 1 V with scan rate 50 mV/s to 200 mV/s at room temperature.. At scan rate of 250 mV/s, a peak was clearly observed from 300 mV to 750 mV. The peak should be attributed to an oxidation process of occurred to blood sample.
Complex permittivity, complex permeability and microwave absorption properties of human blood
Authors: Handoko E , Fahdiran R , Budi S , Saptari S A , Humairrah A , Alaydrus M , Mutmainnah Z , Puspitaningrum R
Published: December 2019

This paper reports a method for measuring for the complex permittivity, permeability and microwave absorption properties of human blood of healthy human body. The proposed measurement method can be a useful technique for microwave absorption properties of human blood. The measurement using a waveguide in the microwave band. In order to measure the s-parameter of human blood, a sample should completely fill in the waveguide end and the samples holder using the vector network analyzer (VNA). The complex permittivity and permeability of human blood are resulted in the frequency range from 7 to 13 GHz. Their complex permeability and permittivity, microwave absorption properties values were calculated. The blood sample has the magnetic loss and magnetic energy dissipation. The reflection loss (RL) of blood sample has different absorption with its minimum value of -3.53 dB at 9.36 GHz.
The profile of critical thinking skills students on science learning
Authors: Hidayati Y , Sinaga P
Published: December 2019

Critical thinking skills are an important and necessary skill to confront the challenges in the 21st century. Critical thinking define as basic skills that should be owned by someone to be able to develop thinking skills at a more complex level. This research is aimed to determine junior high school students’ critical thinking skills in science learning. This research is descriptive qualitative research using instruments developed based on aspects of critical thinking skills according Ennis which include elementary clarification, basic support, inference, advanced clarification and strategies and tactics. The subjects in this research were 30 students in grade eight of a junior high school in Bandung which was chosen using purposive sampling technique. The results of the study show that the average percentage of the five aspects of critical skills received by students is 45 and falls into a very low category. The conclusion from this skill of the students still was in a low category, so that needed a way to enhance on indicators of students’ critical thinking skills.
Phase transition in one-dimensional hydrogen chain: A dependence on basis orbitals, cut off radius, and doping
Authors: Prayitno T B , Fahdiran R
Published: December 2019

We demonstrated the dependence of the phase transition in the one-dimensional hydrogen chain on the basis orbitals, the cut off radius, and the doping. For reducing the computational cost, we employed the so-called generalized Bloch theorem, where a hydrogen atom was used in the unit cell. For the non-doped case, we showed a strong dependence of the phase transition on the basis orbitals and the cut off radius, which yields either the antiferromagnetic ground state or the ferromagnetic ground state. When the doping was considered, the spiral ground state appeared between the antiferromagnetic state and the ferromagnetic state. Therefore, we showed that the doping induced the spiral ground state.
Controlling band gap of monolayer MnCl2 with LDA+U
Authors: Prayitno T B , Fahdiran R
Published: December 2019

We performed the noncollinear first-principles calculations to control the band gap of 1T monolayer MnCl2 using LDA+U. It was shown that the increase of the band gap is proportional to the increase of the effective Coulomb energy U, as long as the magnetic moments of the atoms do not reduce. The reduction of the magnetic moment leads to the so-called low spin state, in which the magnetic moment is almost half of the magnetic moment of the high spin state. It seems that the monolayer MnCl2 can be a promising candidate for the spintronics applications.
Implications of higher order tensor in Einstein field equations on vacuum condition
Authors: Prayitno T B , Fahdiran R
Published: December 2019

We investigated the implications of introducing the higher order tensor in the Einstein field equations for the Schwarzschild metric on the vacuum condition and non de Sitter. Since the components of this tensor contain the fourth-order derivative, the solution of the Einstein field equations was solved by using the Frobenius method. To see the implications, we tested two cases, i.e., the deviation of light and the time delay of light. We found that the deviation of light has no correction while the time delay of light needs a correction.
Analysis characteristics of viscosity coefficient using viscometer stromer
Authors: Malik A , Hakiki M A , Imiyati N , Kurnia P , Zakwandi R , Setya W , Chusni M M
Published: December 2019

This research aims to develop methods of measuring the coefficient of viscosity using viscometer stromer are analyzed using Newtons law of 1. The viscometer stormer came from the simple equipment modifications in the form of a hollow cylinder, laver, a pulley, a ruler, a stopwatch, burdens, taps, boards, iron rods, and rope. The trial results do indicate fairly accurate results with the reference. Furthermore, the equipment used, reaching a level of precision that is good at the moment in the trial to the school community. According to the trial results obtained the relationship between viscosity coefficients against time is inversely proportional. The resulting coefficient of viscosity is greater when the mass of the given object is getting bigger. Thus, the viscometer stomer can describe the relationship between the value of the viscosity coefficient, the time and mass of several types of liquid.
[RAV] current meter: Manufacture a measuring instrument of water current using a spring balance
Authors: Malik A , Zakwandi R , Agustina R D , Anjani R , Syamsudin N R , Rochman C , Nasrudin D
Published: December 2019

This research aims to build physics tools of measurement of river flow is current. The tool was developed with the balance spring as a means of collecting the data. data measurement results then analysed mathematically. It is designed using chloride polyvinyl (PVC) which is waterproof. The result of the test tool shows the average error value of 0.3342% and the value of the standard deviation of 0.1893. So, it can be stated that RAV current meter has a level of accuracy and the level of accuracy that is high enough. This equipment still needs to be optimized by performing test audiences to see the ease of the user. In addition. the size of the adjustment to the attention of the research further.
Selection method to identify the dominant elements that contribute to magnetic susceptibility in sediment
Authors: Iswanto B H , Zulaikah S
Published: December 2019

Measurements of magnetic susceptibility (χ) and chemical elements have been carried out on soils or sediments in various depositional environments for various purposes. Theoretically, the magnetic mineral content in nature is generally ferromagnetic which is characterized by the presence of a dominant element of Fe and is positively correlated with the value of χ and can be used as an indicator of environmental conditions. However, the presence of measured Fe elements does not always have a positive correlation with χ and if it has a positive correlation, often the correlation coefficient is very low. In this study, we offer simple steps to find out the dominant elements that correlate significantly with χ. First, a correlation analysis between χ and each measured element is carried out; Second, the elements that have a positive correlation coefficient are chosen; Third, summed all elements that have a positive correlation with χ and carried out a correlation test to χ (R). This step has been tested on sediments in various depositional environments and yields conclusions, if there is a positive correlation value between Fe and χ, even though the low value of r ∼ 0.3, a very significant correlation value will be obtained between total elements having positive r and χ, which is R approximately 0.9. The discovery of a dominant element that contributes to χ, then it will facilitate the determination of the minerals carrying magnetic properties.
TUMPULS teaching aids as an alternative media for physics learning
Authors: Mulhayatiah D , Ningsih R F , Suhendi H Y , Nasrudin D , Yuningsih E K
Published: December 2019

Development of learning media needs to increase students’ interest in learning and stimulate teacher creativity in creating an interactive learning atmosphere. This study aims to develop teaching aids as an alternative to physics learning media in momentum material. The method used in this study is research and development with the stages of analysis, design, development, implementation and evaluation. The stage described in this study is the development stage in the laboratory test section. The laboratory test results for momentum props found that the relative error of the data obtained for the initial momentum was 0.1% and the final momentum ranged from 9%. The momentum props developed were able to present data and show momentum calculations through equations.
Waste to Energy (WtE) as the basis for developing physics learning materials
Authors: Nasrudin D , Rachmadanti F E , Rochman C , Mulhayatiah D , Millah M F , Malik A
Published: December 2019

Many social and environmental issues that the world of education can respond to. One of them is learning physics. One issue that is still a problem is urban waste. This paper aims to describe the development of physics teaching materials by using the waste to energy issue as a learning context. The method used is Research and Development with ADDIE design. This study shows that: (1) student literacy about waste to energy is still low so it needs to be improved (2) The design of physics teaching materials must contain four literacy domains namely content, process, context and attitude (3) Physics teaching materials in the context of waste to energy is declared feasible to use (4) The results of limited implementation in several schools show positive results and (5) Further development is needed to get teaching materials that are simpler, flexible, easy to learn, easy to understand and easy to study. This study concludes that we can present many social topics as the application of the main principles of physics, one of which is Waste to Energy by integrating it in physics learning. Integrated physics teaching materials are proven to improve student literacy on the issue of waste to energy.
Learning materials of natural science of characters-based problems on light and optical concept
Authors: Tirmayasari T , Jufri A W , Harjono A
Published: December 2019

Problem-based learning (PBL) is one of the recommended teaching materials model in the 2013 curriculum. The purpose of this research was to develop learning materials of natural science of characters-based problems on light and optical concept in junior high School four east Praya. Research and development study refering to Dick & Carey model. Validaton by three experts (media, content, and language). The results of the first validation obtained an average of 3.6 and second validation obtained an average of 4.1, this indicates that learning materials are feasible and relevant to be used as learning resources for class VIII. The results of the reading level by Kincaid readability showed that out of 76 pages there were 40 pages of text that corresponded to the junior high school class VIII with a percentage of 52.6%, while the non-compliant text contained 36 pages with a percentage of 47%. The results of a limited trial showed that responses from students by 28% with categories quite interesting, 36% interesting, and 36% very interesting. In conclusion, learning materials of natural science of characters-based problems on light and optical concept was feasible to be applied in science learning processes.
Development of tools problems-based learning model assisted by virtual experiment to increase students’ generic science skills
Authors: Jiniarti B E , Harjono A , Makhrus M
Published: December 2019

Type of research is research and development (R &D). This development research aims to produce physics learning tools using qualified problem based learning model assisted by virtual experiment has a valid, practical, and effective which to increase students generic science skills in subject of optical instruments. In this study, the generic skills that discussed on the science field, called generic science skills. The development model had used a four-D model consisting of define, design, develop and dessiminate phases. Trial of product conducted in students of eleventh grade of the state senior high school 1 east Praya in second semester the academic year 2018/2019and the method used was pre experiment. Generic science skills (GSS) was measured using student worksheet when the learning process was descriptively analyzed based on descriptors appeared on the observational sheet. Based on GSS observation data, that students were in the category “skilled” and “highly skilled”.
A systematic effect of clay volume on porosity – p-wave velocity relationship
Authors: Prakoso S , Burhannudinnur M , Yasmaniar G , Rahmawan S , Irham S
Published: December 2019

It has been believed that P-wave velocity is strongly influenced by complexity of pore arrangement. In Sandstones, the pore complexity is influenced by the constituent material of rock including clay volume. Rocks with a certain clay volume will have a certain pore geometry and pore structure and also, they have certain qualities. This research is intended to study the effect of clay volume on rock quality and its effect on the relationship of porosity with P-wave velocity. This research used 3 sandstone data sets from the North West Java basin, Kutai basin and Southern Sumatra basin. The mineralogy of each rock sample is dominated by quartz and kaolinite. The three data sets show the relationship of porosity and P-wave velocity can be clearly separated by clay volume. Each of these rock groups indicates different qualities called rock types. It can be concluded that the variation of P-wave velocity is influenced by rock type. The lower rock quality is denoted by the larger rock type number and is indicated by the increase in clay volume.
Coating of TiO2 nanoparticles in the surface of transparent plastic grains and its aplication for photocatalyst under solar irraidation
Authors: Amalia I F , Gumilar S , Ismail A , Amalia L , Abdullah M
Published: December 2019

A cylinder milling has been modified by adding a heating controller for coating TiO2 photocatalyst on the surface of polymer at constant temperature. By testing the polystyrene, polypropylene, and linear-low-density polyethylene polymer density before and after coating, it is obtained that polypropylene polymer is suitable for polymer-coated TiO2 because the surface is transparent and can remain floating on the surface of water although it has been coated with TiO2 catalyst. Coating process of TiO2 nanoparticles on the surface of the polypropylene is performed through three stages, that is stirring while heating in the cylinder milling, washing, and drying. The coating temperature is 1100C for 90 minutes. Photocatalytic activity was observed by testing the photodegradation of methylene blue dissolved in water using a container with a surface area 750 cm2 and illuminated by sunlight for 12 days. The experiment was done at 6 containers with similar volume and area and variable amount of catalyst, which is without catalyst (0 g) to 5 layer of catalyst (550 g). From the colour, turbidity, and UV-Vis characterization, the methylene blue decomposition effectively occurred with amount of 220 g catalyst (2layer of catalyst).
Application of the contextual teaching and learning model as an efforts to improve student results and scientific performance of student physics
Authors: Arygunartha G Y , Situmeang Y P
Published: December 2019

This study aims to improve student learning outcomes and scientific performance of physics. This research is a classroom action research. Subject from this study were students in the semester an odd number of school year 2018/2019 as many as 19 male students. This research implemented in two cycles with each cycle stage consisting of planning, action, observation/evaluation, and reflection. The results of this study indicate that 1) there is an increase in students’ scientific performance. In the first cycle, the average value of performance the scientific achievement of students is 77.37 with a fairly high category, while at the second cycle increased to 87.90 with a very high category, 2) an increase student physics learning outcomes. In the first cycle, the average value of physics learning outcomes is achieved students are 73.00 while in cycle II it increases to 77.50. Research This class action is categorized as successful because it has reached the level of completeness Hornax of 94.7%.
Implementation of OPTIKU pocket book based Android for enhancing problem solving ability
Authors: Mulhayatiah D , Fitriyanti N , Setya W , Suhendi H Y , Nasrudin D , Malik A
Published: December 2019

Problem-solving ability is one of the abilities that must be possessed by students in the 21st century. Field studies obtain data that some students have low problem-solving abilities. This study aims to determine the feasibility of learning, improvement of problem-solving abilities, and differences in problem-solving abilities of students between classes using Android-based pocketbook learning media with classes that do not use Android-based pocketbook learning media on optical instrument concept. The method used in the study was a quasi-experiment with the design of a non-equivalent control group. The sample was selected using a purposive sample technique. The results showed that the implementation of learning was classified as a good category and there were differences in the problem-solving abilities of the two classes of students because the N-gain experimental class was 0.63 and the control class was 0.53. This shows that Android-based pocketbook learning media can improve students’ problem-solving abilities in the optical instrument concept.
Kalman filtering to real-time trace water level measurements using ultrasonic sensor
Authors: Iswanto B H , Parmono I F , Delina M
Published: December 2019

Water level monitoring systems are needed in various related fields. However, to accurately determine water levels typically difficult due to the effect like sloshing in dynamic environments. In this paper, we proposed Kalman filter based approach to reduce uncertainty in the water level measurements. Experiments have been performed by filling the tank with water and installing an ultrasonic sensor module at the top center of the tank. The water tank is vibrated with an artificial vibrator, then measuring the water level is done by the ultrasonic sensor. To reduce measurement errors we introduced the Kalman filtering. This technique is developed for improving the precision of water level measurements in the presence of various noise sources. The Kalman filter performance is demonstrated to be adaptive to real-time noise. Experiment results indicate reducing the errors of measurement significantly up to about 60% for a dynamic water condition by adjusting appropriately the Kalman filter tuning parameters.
Band gap control of bilayer zigzag graphene nanoribbon by direction of magnetic moment
Authors: Prayitno T B , Budi E , Fahdiran R
Published: December 2019

We have demonstrated the first-principles calculation to tune the band gap of the bilayer zigzag graphene nanoribbon by arranging the direction of the magnetic moments of carbon atoms at the edges. These directions were specified by the polar angle, as defined in the spherical coordinates. From the ferromagnetic configuration to the antiferromagnetic configuration, as the polar angle increases, the band gap increases. We also showed that the ferromagnetic configuration leads to the metallic system while the others lead to the insulator, in a good agreement with the previous calculations. These results indicated that the bilayer zigzag graphene nanoribbon is potential for the spintronics devices.
Dilated cardiomyopathy with long QT secondary to hypothyroidism and hypocalcaemia in patient with post total thyroidectomy: A case report
Authors: Yudistira K A , Pranata I G B , Bagiari K E
Published: December 2019

The linkage between cardiac dysfunction and the lack of thyroid hormones has been well elucidated. A case involving a woman aged 44 years suffering a dilated cardiomyopathy (DCM) and long QT secondary to hypothyroidism and hypocalcaemia emerges. Thyroid hormone acts on the myocardium of the heart and peripheral blood vessels. There are two types of thyroid hormone effects, such as genomic and non-genomic. These effects are associated with cardiovascular and hemodynamic function. The prolongation of the QT interval is the most overlooked and well-documented sign in hypothyroidism. Ventricular fibrillation is usually the leading factor for the long QT syndrome. The incidence is characterized by an increased risk of sudden death and the abnormal QT-interval prolongation on the surface of ECG. The mechanism of hypothyroidism on the occurrence of the ventricular tachycardia and the OT prolongation is unrecognized, and although coexistent, the effects might be distinctive.
Fouling resistance study of poly (ether sulfone) ultrafiltration membrane which in-situ polymerized with polydopamine
Authors: Meirisa F , Muchtar S , Arahman N , Mulyati S
Published: December 2019

This works focuses on the fouling resistance evaluation of polydopamine-blended poly (ether sulfone) (PES) ultrafiltration membrane for water treatment application. The supporting PES membrane was prepared via a common phase inversion method. The dopamine was introduced to the membrane by blending technique and the modification occurred by in-situ polymerization of dopamine into polydopamine which triggered by peroxide. The antifouling performances were studied in terms of flux recovery, reversible fouling, irreversible fouling, and total fouling. The relevant characteristics of the membranes such as surface porosity, chemical composition, water permeation, and solute rejection were also provided to support the analysis of antifouling performances. The results revealed that the presence of polydopamine in the membrane system significantly enhanced the fouling resistance of the polydopamine-blended PES membrane. The hydrophilic component in polydopamine reduced the interaction of membrane with foulant thus lowered the total fouling of only 18.92% with 13.50% reversible fouling and 5.42% irreversible fouling for modified membrane. In addition, the polydopamine-modified membrane successfully recovered up to 95% of the flux after backwashing, much higher than that of original PES which was only 67%.
Removal of Fe (II) in groundwater using rice husk-sourced biosorbent in continuous column adsorption
Authors: Maliki S , Rosnelly C M , Adisalamun A , Husin H , Bilqis N
Published: December 2019

Ferrous is one of the groundwater contaminants that negatively impacts health and the environment. The allowed ferrous content is < 1 ppm in water for daily use. Removal of Fe in groundwater by adsorption using low-cost bio-sorbent from rice husk has been conducted. The process was carried out in continuous mode using two types of rice husk-sourced adsorbents, one was only carbonated at 400 C and another was followed by a physical activation at 650 C. To study the effects of physical activation on the surface characteristics, both types of biosorbents were characterized by Scanning Electron Microscope and Fourier-transform infrared spectroscopy. The concentration of artificial sample before and after adsorption was evaluated using the Atomic Absorption Spectroscopy. From the results, the adsorption using physically activated sorbent had greater removal efficiency of 74.02% compared to that of without activation treatment, which was only 65.70%. In addition, the concentration of ferrous was successfully reduced to 1,029 and 0.779 ppm from the initial concentration of 3 ppm for the process using the adsorbent without and with activation, respectively. It can be concluded that the physically activated rice husk has the potential to be used for adsorption of Ferrous in continuous column.
Enhance photocatalytic of hydrogen production from water-glycerol solution over RuO2-loaded
Authors: Husin H , Pontas K , Zaki M , Darmadi D , Masna A
Published: December 2019

Study of hydrogen production from aqueous glycerol solution on RuO2-loaded LaNaTaO3has been studied. This research aim is to investigate the influence of co-catalyst RuO2and glycerol as a sacrificial reagent on the photocatalytic process of hydrogen production. La-doped NaTaO3was prepared via sol-gel route. The RuO2was loaded onto the LaNaTaO3surface by impregnation method. The sample was characterization by Scanning Electron microscopy (SEM) and X-ray Diffractometer (XRD). From XRD spectrum shows that the La-NaTaO3photocatalyst has high crystallinity. The SEM analysis indicates that the size of La-NaTaO3photocatalyst is ranging from 100 to 250 nm without agglomeration and RuO2as a co-catalyst is well loaded into the La-NaTaO3surface. The rate of hydrogen production increased significantly with a glycerol concentration. Loading RuO2on La-NaTaO3photocatalyst is proved to increase the rate of hydrogen production of 3.2 times with the addition of glycerol as a sacrificial reagent. The highest hydrogen production activity was obtained for 0.3 wt.% ruthenium loading. The role of co-catalyst RuO2and glycerol as a sacrificial reagent has enhanced the performance of La-NaTaO3photocatalyst since both play an active role in the separation efficiency of electrons and holes and the reaction of hydrogen formation.
Initial screening of AOS, its performance in EOR to improve oil recovery
Authors: Pratiwi R , Setiati R , Andryan R , Fadliah F , Fajarwati K
Published: December 2019

Continuous increasing of fuel need in Indonesia, at least in the last ten years, is the reason for improving domestically crude oil production. Exploitation in the form of oil drainage activities needs to be investigated further. Surfactants as an agent that believed can reduce interfacial tension, need to be determined the formulation and compatibility in their use for oil drainage from reservoirs. Screening of the conditions of surfactant operation needs to be done in order to provide optimal oil recovery. In this study a surfactant behavior test was carried out on AOS (Alpha Olephin Sulfonate) in a laboratory scale, using sandpack as a sandstone reservoir rock prototype, measured the effect of salinity and concentration on oil recovery in chemical flooding, where interfacial tension (IFT) as the main variable. From the measurements, it was found that a surfactant concentration of 1.5% worked optimally in formation water with a salinity of 10,000 ppm, by producing IFT of 16,75 mN/m and recovery factor of 7.5%. This is compatible with the properties of AOS surfactants which can work well in solutions with low salinity The emulsion formed shows that the surfactant works in the upper phase, or tends to dissolve in oil, correlates with the basic ingredients of surfactant which is an oil base.
Laboratory study on the effect of salinity, surfactant type and concentration to recovery factor for carbonate rock
Authors: Yulia P S , Kasmungin S , Fathaddin M T
Published: December 2019

The needs of petroleum as energy, have increasing while the oil production has depleting. Due to that needs, the method of Enhanced Oil Recovery (EOR) or in other hands as tertiary recovery (after primary recovery and secondary recovery) is being developed. EOR has many methods; one of the methods is chemical injection that consists of surfactant, alkaline and polymer. In this experiment, the author is using surfactant injection. The using of surfactant is to decrease the interfacial tension between oil and water, with the result is surfactant can displace oil through rock pores. This study will be discussing about the effect of salinity, surfactant types and surfactant concentrations on surfactant injection for carbonate rock. The surfactant types are Alpha Olefin Sulfonate (AOS) and Tween 20. The surfactant concentration varieties are 0,1%; 0,25%; 0,5%; 0,75% and 1%. Salinity varieties are 10.000 ppm; 15.000 ppm; 20.000 ppm and 25.000 ppm. From this study, it had determined that surfactant can displace the oil from rock pores based on the influence of salinity, surfactant concentrations and surfactant types to recovery factor. The determination of recovery factor will be using these methods; Amott apparatus (imbibition process) and injection using core holder and syringe pump. From experiments that have been done, the effect of surfactant injection on carbonate rocks is more optimal in core flooding process compared with imbibition process, with the recovery factor percentage is 57%. Core flooding process uses the external thrust, therefore the oil displacement with surfactant is more evenly and optimally.
The effect of concentration of Ceremai (Phyllanthus Acidus) Fruit extract on FH (Friesh Holland) cattle milk clumping in cheese making
Authors: Mulyani L S , Ardiana C , Kurniasih N , Hernawati D , Rohayat A
Published: December 2019

Most of the milk consumed by humans comes from cow’s milk. The processed products are cheese as a result of the separation between whey and curd through the fermentation process. This process involves microbial activity that takes place in aerobes and anaerobes. Making cheese involves the process of clumping milk with helping of the rennet enzyme. There are difficult to obtain and the price is relatively expensive. So that a replacement for this enzyme is needed. Ceremai fruit extract can be used in the process of milk clotting. The research aims to find the concentration of it which optimally influences the clotting process of FH (Friesh Holland) cow milk in cheese making from the time of clumping. It is obtained by blending until smooth, then poured into a filter and squeezed to get extract. The extract was used for 5 treatments with a concentration variation of 50%, 60%, 70%, 80%, and 90% with 5 repetitions. The results showed at the concentration of 90% produces the optimal clumping time with an average clumping time of 5.4 minutes. So influences the time of clumping of cow’s milk in making cheese and it can be used as an alternative ingredient for rennet enzymes.
Betung Bamboo Shoot (Dendrocalamus asper Backer ex Heyne) Extracts: Accelerating the growth of Java Apple (Syzygium samarangense) stem cuttings
Authors: Mulyaningsih S , Sumiati D , Hernawan H , Robbiyani R , Sriwahyuningsih S
Published: December 2019

The pruning waste of Java Apple (Syzygium samarangense) tree branch can be used for its propagation by stem cuttings. The rooting process can be accelerated with the help of growth regulators, one of which is betung bamboo shoot extract. Using a randomized block design, this experiment aims at examining the effect of betung bamboo shoot extract with concentrations of 0%, 10%, 20%, 30%, 40% and 50% on the growth of Java Apple stem cuttings. The samples were 48 stem cuttings with a diameter of 1 cm and a length of 15 cm. The results showed that betung bamboo (Dendrocalamus asper) extracts could accelerate the propagation process. The optimum concentration was 50%.
Potential amylase-producing yeast isolated from indigenous fermented beverages originating from Bali, Indonesia
Authors: Sukmawati D , Arman Z , Sondana G A , Fikriyah N N , Hasanah R , Afifah Z N , Balqis M , Enshasy H E , Husna S N A , Rahayu S , Kurniati T H , Puspitaningrum R
Published: December 2019

Indonesia has many fermented beverages, and yeast become one of the agents in fermented process. Yeasts has a role to transform carbohydrate complex into simple compounds with release secondary metabolism to environment like amylase enzyme. This study aims to get the isolate of yeast that can potentially produce amylase enzyme. This research conducted in October 2018 until March 2019 in Microbiology Laboratory of Universitas Negeri Jakarta. The screening test of potential isolate producing amylase enzyme was performed on yeast isolate from eight source of indigenous fermented beverages that can grow in YMA medium with pH 2. Screening was carried out on YPSA medium with diffusion agar method. From 50 Isolates, 16 isolates with the codes IB4, IB15, IB20, IB21, IB26, IB36, IL78, IL80, IL81, IL86, IL88, IL97, IL113, IL136, IL146, and IL150, were able to form clear zone after 1-day incubation in room temperature. The highest amylolytic index was produced by IL86 (1,019 mm). Forming the clear zone is proof that yeast can transform starch become simpler sugar like maltose as iodine-starch reaction is resulting amylose helix and iodine become I3
− that filled main core helix. In addition to this, iodine forms complexes with starch molecules showed a dark purple colour.
Performance of 0-14 weeks-aged super free-range hens that are fed by fermented coconut pulp flour-contained ration
Authors: Suwitari N K E , Suariani L , Yudiastari N M , Kaca N , Tonga Y
Published: December 2019

The research was carried out at the Basic Laboratory of the Faculty of Agriculture, Warmadewa University with a level of use of fermented coconut pulp, namely R0 (ration that contains no fermented coconut pulp, R1 (ration containing 5% fermented coconut pulp flour), R2 (ration containing 10 % fermented coconut pulp) and R3 (rations containing 15% fermented coconut pulp). Each combination of treatments was repeated three (3) times, and each replication consisted of 4 super female free-range chickens. Variables observed included: 1). Age of chicken growth includes the weight gain and final weight of super free-range chicken, 2) Percentage of carcass and non-carcasses for super free-range chicken, 3) Feed Conversion Ratio (FCR, and 4) Feed consumption. From this study it was found that the giving of coconut pulp flour was fermented up to 10% (R2) significantly (P<0.05) could increase weight gain and final weight and flour dregs fermented coconut to the level of 10% also decreases ration consumption and the conversion of ration for super female chicken 14 weeks old.
Design of educational games oriented to chemical literacy on petroleum material
Authors: Sari S , Safitri I , Farida I
Published: December 2019

This study uses the stages of the Research Based Design method to produce an educational game oriented to chemical literacy on petroleum material. This research is driven by the importance of a visual learning media in order to improve the ability of chemical literacy in petroleum material so that students can connect between knowledge of concepts and phenomena that occur. The aim of the study is to describe the appearance of educational games oriented to chemical literacy on petroleum material. Based on the results of the study, it is obtained that the chemical literacy-oriented educational game products in the form of chemical monopolies and chemical energy ladders which have characteristics such as game rules that modify the monopoly and snake ladders games equipped with questions oriented to chemical literacy, obstacles in the games show the levels of difficulty and levels of thinking as well as different visualizations that illustrate the context and application of petroleum.
The making of metal coating props oriented chemical representation
Authors: Mayangsari D , Irwansyah F S , Farida I
Published: December 2019

The purpose of this research is to produce metal coating props that oriented to chemical representation and find out the results of validation and feasibility of the props that has been made. This research used research and development method with stages of analysis, design and development. Based on the results of this research, the product is obtained in the form of metal coating props with the characteristics of combining macroscopic, submicroscopic and symbolic representations with guidebooks and worksheets. Validation results indicate that the product is valid with the acquisition of the value of rcount on props of 0.93. The results of feasibility tests conducted on 3rd grade of 27 Senior High School Bandung showed that props are very feasible with the percentage of successive value of 97%. High validation and feasibility values are caused by props that have met the criteria as a good medium and in accordance with metal coating material. The impact, the resulting props can be used as a medium that can help students gain a complete understanding of the concept of metal coating.
Rosa sp and Hibiscus sabdariffa L extract in ethanol fraction as acid base indicator: Application of green chemistry in education
Authors: Paristiowati M , Moersilah M , Stephanie M M , Zulmanelis Z , Idroes R , Puspita R A
Published: December 2019

Green Chemistry principal was introduced in an academic environment in the 1980s as guidelines for sustainable development focused on chemistry. Efforts to realize these expectations can be applied through education by developing learning process based on environmental. This study aims to apply the concept of Green Chemistry in education, especially chemistry learning by producing natural acid-base indicators from the extract of roses (Rosa sp) and Rosella (Hibiscus sabdariffa L). These indicators are produced by the method of extraction using 96% ethanol solvent in an acidic atmosphere at pH 3-4. The results of maceration then extracted in three different solvents (ethanol, n-hexane, and chloroform). The extract was tested in solution with pH 1-12 and used as an indicator to identify the solutions and titration in acid-base topic. It concluded that the roses and Rosella can be used as an alternative raw material for acid base indicator. The use of roses and Rosella indicates an attempt to have applied the principles of green chemistry, including the prevention of the formation of hazardous wastes, the design of safe chemical products, the use of renewable materials, the design of materials that are easily degraded, and the use of safe solvents.
Analyze of chemistry teacher profiles using Technological Pedagogical and Content Knowledge (TPACK) framework
Authors: Paristiowati M , Hadinugrahaningsih T , Fitriani E , Imansari A , Nurhadi M F
Published: December 2019

This study aims to analyze the profile of technological pedagogical and content knowledge (TPACK) chemistry teachers at one of the schools in Jakarta. The criteria for the teachers analyzed are professional teachers who have been certified and have more than 20 years of teaching experience. The method used in this study is a qualitative descriptive research method. The data sources were collected through the TPACK questionnaire, lesson plan analysis, observation of the learning process, and interviews. The results show that chemistry teachers can apply learning methods that vary each meeting according to the characteristics of acid-base material. The teacher also utilizes technology information & communication (ICT) based learning media to simplify and clarify material delivery. It can be concluded that teachers have pedagogical content knowledge (PCK) and technological content knowledge (TCK). The use of ICT media such as interactive power points, videos and mobile phones to support selected learning methods, shows that teachers are also competent in technological pedagogical knowledge (TPK). The results of the study concluded that the teacher had integrated all TPACK components into acid-based learning so that they belonged to the action category (Action Level/An) at the TPACK competency level. This result was obtained base on CK, PK, TPK competencies that met the standard conception (Cn) category, and TK, PCK, TCK competencies that met the standard perception (Pn) category. Cn are indicated by understanding theories about TPACK components and their implementation through learning. While the Pn only understands the theories of components from TPACK.
Ab initioMP2 and DFT studies of ethyl-p-methoxycinnamate and its derivatives as corrosion inhibitors of iron in acidic medium
Authors: Hadisaputra S , Purwoko A A , Hakim A , Savalas L R T , Rahmawati R , Hamdiani S , Nuryono N
Published: December 2019

The efficiency of ethyl-p-methoxycinnamate(EPE) and its derivatives as corrosion inhibitors of iron in acid environment has been studied to find the relationship between molecular structure and electronic parameters with their efficiency of corrosion inhibition. Theab initioMP2 perturbation theory and DFT method were applied to calculate molecular structure and electronic parameters of inhibitors. Computational and experimental corrosion inhibition efficiency show that the electronic properties of molecules, including the orbital molecular frontier energy (HOMO and LUMO energy), ionization potential, electron affinity, electronegativity, number of electron transfer from inhibitor to metal and interaction energy have a strong relationship with inhibition performance. Interaction mechanism obtained from natural bond orbital analysis was employed to study the interactions between inhibitors with iron metal in more detail. The presence of electron donor groups within the frameworks of inhibitors has a less significant effect compared to π-electron contribution on corrosion inhibition performance.