bluuebunny/crossref_metadata_2025 huggingface dataset:
Wireless software-hardware complex for testing semiconductor structures
Authors: Loganchuk S M , Touel L , Chebotarev S N , Goncharova L M , Varnavskaya A V , Touel S , Mohamed A A A
Published: December 2019

Wireless system for measuring current-voltage characteristics was developed. Software for a smartphone was developed in the integrated development environment Unity. The data about current and voltage was transmitted by Bluetooth and Wi-fi for smartphone and computer respectively. I-V curves were built on computer using program, developed in the Visual Studio package and coded in C#. For data verification the simulation of diodes’ parameters was provided by solving the Poisson equations and the drift-diffusion model.
Magnetic-field-driven electron transport in SOI back-gate device
Authors: Shanidze L V , Tarasov A S , Lukyanenko A V , Rautskii M V , Yakovlev I A , Zelenov F N , Baron F A , Volkov N V
Published: December 2019

In this work, we studied the electronic transport properties of silicon nanowire field-effect transistors with a back gate. A nontrivial magnetic field influence on the drain current at low temperature (10 K) was found. The strongest effect was observed in the majority carrier accumulation mode. In this mode magnetic field of 0.5 T increases current through the device by more than an order of magnitude. The paper describes the possible mechanisms of the magnetic field influence on the electronic transport characteristics of the structures.
Contact resistance and lifecycle of an ohmic MEMS switch with single and multiple contact bumps
Authors: Marukhin N V , Uvarov I V
Published: December 2019

Microelectromechanical systems (MEMS) switches potentially have a wide range of applications due to their promising characteristics, but relatively low reliability limits implementation of these devices. Contact region degrades during operation that increases the resistance and lowers the lifecycle. In this paper we demonstrate how these parameters can be enhanced by changing the design of the switch. The devices of four types having different number of contact bumps and beams are fabricated by surface micromachining and tested in a cold switching DC regime. The switch with two bumps has about 25% lower contact resistance and almost two times longer lifecycle than the one-bump device. Using four beams instead of one gives threefold increase of the lifecycle, but does not reduce the resistance significantly.
Microwave low mass-dimensional frequency standard on Hg- 199 ions
Authors: Lukashev N A , Davydov V V , Glinushkin A P , Yu Rud’ V , Lukyantsev V S
Published: December 2019

In the paper the design of a magnetic trap for low mass-dimensional microwave frequency standards is presented. The dependencies between the number of registered photons by PMT and magnetic field values are established. The new algorithm for optical processing is developed. The results comparison of experimental Allan deviation researches for different designs of microwave standard on 199Hg+ ions are performed.
Investigation of the piezoresistive properties and temperature coefficient of resistance of epitaxial GaN layers for applications in MEMS and thermal flow sensors
Authors: Kazakin A , Enns Y , Mizerov A , Kleimanov R , Bouravleuv A
Published: December 2019

The paper presents the results of an experimental determination of the piezoresistive gauge factor and temperature coefficient of resistance of a GaN films grown by molecular beam epitaxy on sapphire substrates. The measured values were used to calculate the design and characteristics of the GaN hot-wires anemometer for the MEMS gas flow sensor.
Contrast simulation in the phase shift dynamic magnetic force microscopy depending on the MFM probe geometry and materials
Authors: Zhukov M V , Belousov K I , Golubok A O
Published: December 2019

The gradient of the magnetic force caused by the interaction of various shapes magnetic nanoprobes with magnetic materials has been simulated. Because the force gradient is proportional to the phase shift in probe oscillations the data obtained allow us to compare the contrast of dynamic magnetic force microscopy images for probes with various shapes. A comparison of standard pyramidal probes and probes with cylinder-shaped nanowiskers with different aspect ratios has been carried out. The probes with optimal parameters such as the shape, the thickness and type of the magnetic coating giving the maximum phase shift and as a result giving the best quality visualization of magnetic fields on the sample surface in the phase shift mode have been selected.
Laser sintering of silver nanoparticles deposited by dry aerosol printing
Authors: Khabarov K M , Kornyushin D V , Masnaviev B I , Tuzhilin D N , Efimov A A , Saprykin D L , Ivanov V V
Published: December 2019

This work is devoted to the sintering of silver nanoparticle arrays in the form of lines by the local treatment with laser radiation with wavelengths of 527, 1054 and 1064 nm in pulsed and continuous laser modes. The silver nanoparticle lines were formed by the dry aerosol printing, free from organic solvents and surfactants. To form the lines with a width of 25–300 μm and a thickness of 0.1–15 μm a focused stream of nanoparticles with an average size of about 60 nm was used. It is shown that when using continuous laser radiation with a wavelength of 1064 nm, the minimal specific resistance of silver nanoparticle lines was achieved 3 times higher than that for the bulk material was reached.
Composition, structure and hardness of titanium after pulse laser processing in graphite
Authors: Koshuro V , Voyko A , Fomina M , Papshev V , Antropov A
Published: December 2019

The structure, composition and hardness of the surface layer of titanium after laser processing in a solid carburizer (graphite) were studied. As a result of the processing, a coating containing Ti, C, O and characterized by a thickness of up to 10 μm, hardness up to 11.5±0.9 GPa and the presence of nano-sized structural elements was formed on the surface of titanium. The resulting diffusion layer with a fine dendritic structure consisted of Ti and C. The diffusion layer with a thickness of 130±20 μm was distinguished by a high microhardness of 16.7±0.6 GPa.
Synthesis, Raman enhancement, and chemical stability of CaCO3 microparticles with copper coating
Authors: Markina N E , Danchuk A I , Zakharevich A M , Markin A V
Published: December 2019

The aim of the work is the microwave-assisted (MW) synthesis of SERS-active copper nanoparticles (CuNPs) and the core-shell composite based on nanostructured copper layer deposited over CaCO3 microspheres (CaCO3@Cu; 1.4±0.4 μm). The comparison of MW synthesized CuNPs and gold nanoparticles showed the equal orders of magnitude of the Raman enhancement. The temporal stability of CaCO3@Cu samples was found significantly better than that of CuNPs: 4 days vs. 30 min. Stabilizer- and organic solvent-free synthesis of CaCO3@Cu enables to minimize background SERS signal. The applicability of CaCO3@Cu for chemical analysis was showed by detection of antibiotic drug (ceftriaxone) in a range of concentrations which is relevant for practical purposes (5–500 μg/mL).
Magnetic-force microscopy of thin Bi:IG films for thermomagnetic recording
Authors: Vysokikh Yu E , Krasnoborodko S Yu , Danishevskaya Y V , Mikhailova T V , Nedviga A S , Berzhansky V N , Bulatov M F , Churikov D V
Published: December 2019

Thermomagnetic recording on thin films is currently one of the most promising methods for copying records with high density and weak magnetization. These films can be characterized by a couple of parameters very suitable for recording reconfigurable magnetic atomic traps whose geometry is visible. Different types of materials are investigated to be the most effective for thermomagnetic recording propose. In this paper authors showed possibility and features of thermomagnetic recording on Bi:IG thin films. High coercivity thin films with low Curie temperature and different film-lattice mismatch parameters were synthesized. Thermomagnetic recording of magnetic disc was performed. Features of magnetic records were investigated and influence of film-lattice mismatch parameters on meta-stable domain structure that defines the thermomagnetic recording resolution was showed. Magnetic-force microscopy was used for topography and magnetic structure characterization of thin films with different film-lattice mismatch parameters. Some features of films morphology were investigated using atomic-force microscopy with sharp AFM probe.
Molecular dynamics study of As dimer formation on the GaAs (001) As-rich surface
Authors: Prasolov N D , Gutkin A A , Brunkov P N
Published: December 2019

Using the molecular dynamics modelling the study of the process of As dimer formation on the GaAs (001) surface was carried out at different temperatures as a function of time. To describe GaAs properties the bond-order potential was used. It was found that the activation energy of formation of single dimer is about 38 meV, while the dimer dissociation energy is about 2 eV. The characteristic time of the single dimer generation lies in the range 10-6 – 10-8 s for temperatures from 28 to 37 K.
Formation of a Corrugated Graphene Substrate on the Paraffin Surface
Authors: Votyakov S A , Samorodov N A , Pakharukov Yu V , Shabiev F K , Safargaliev R F
Published: December 2019

In this paper, we propose a method of creating a wave-like corrugated surface from graphene nanoparticles. Due to the Kelvin-Helmholtz instability, the graphene suspension flowing onto the melted paraffin forms a wave-like surface. The inhomogeneity wavelength λ can be controlled by changing the relative surface tension.
Influence of carbon in the Sp1 state on the Schottky transition Si-Cd
Authors: Kokshina A , Kochakov V , Vasilyeva O
Published: December 2019

This article presents the results of a study of the photoactive film of metal-carbon system as an example cadmium - linear-chain carbon (Cd-LCC). It is shown that when this system is annealed in a nitrogen atmosphere, the addition of cadmium atoms to cumulene carbon chains occurs. Investigation of the properties of the Si-Cd-LCC system doped with nitrogen showed a significant increase in the photoactivity of the Schottky transition in the Si-Cd system.
Development of technology for the formation of vacuum field emission cells using focused ion beams
Authors: Panchenko I V , Shandyba N A , Kolomiytsev A S
Published: December 2019

The article presents the results of the development of technology for the formation of vacuum field emission structures. Experimental studies of local ion-stimulated deposition of W and C and ion-beam etching were carried out and their effects on the formation of final structures were studied. The technological process of manufacturing nanoscale field emission structures was developed, and experimental samples were fabricated. It is shown that the use of the method of focused ion beams (FIB) demonstrates its advantages compared with other methods.
Features of construction of the scheme of fiber-optic communication system for transmission of analog signals in the frequency range from 0.135 to 40 GHz
Authors: Fadeenko V B , Pchelkin G A , Davydov V V , Glinuchkin A P , Beloshapkina O O , Rud’ V Yu
Published: December 2019

The paper presents the design of a fiber-optic microwave signal transmission line. The use of the developed design of a fiber-optic microwave transmission line allows the radar operating frequency range to be at least doubled. In addition, the number of functional blocks is reduced to ensure the operation of the radar in this frequency range. The results of experimental studies are presented.
Simulation of quantum transport in doped carbon nanotube diode controlled by transverse electric field
Authors: Timkaeva D A , Sibatov R T
Published: December 2019

Using first-principle and semi-empirical methods, optical responses and transport characteristics of hybrid CNT-based diodes are studied. The junction is realized by a combination of doping of one half of a nanotube and applying a transverse electric field to the other. Calculations are carried out in the framework of the density functional theory and the nonequilibrium Green function method. The possibility of using these rectifiers in optical nanoantennas is discussed.
Detailed Monte-Carlo simulation of PMMA chain scissions in e-beam lithography
Authors: Sidorov F A , Rogozhin A E
Published: December 2019

Detailed Monte-Carlo simulation of e-beam events in PMMA/Si system has been carried out. Polymer chains are modeled using random walk algorithm with subsequent assignment of simulated e-beam events to certain monomers. The processes leading to PMMA chain scission are determined to be ionization events on C atoms of PMMA backbone bond due to analysis of resist weight distributions, obtained by gel permeation chromatography.
Laser formation of nano-Si structures in glasses
Authors: Babich E S , Redkov A V , Melehin V G , Khlopin D , Lipovskii A A
Published: December 2019

The irradiation of a BOROFLOAT® 33 glass plate with lithographically-fabricated array of aluminum nanodisks on the surface by a focused low-power 523 nm laser beam resulted in the formation of silicon nanocrystals in the subsurface layer of the glass. The nano-Si was registered with Raman scattering technique. The formation of the nano-Si is local and grown nanocrystals are stable.
Discriminating a Nuclear Blast from A Natural Seismic Event Using A Full Moment-Tensor Inversion Method
Authors: Prastowo T , Madlazim  , Supardiyono
Published: December 2019

Identification of seismic signals if they are generated by tectonic or volcanic origin or underground nuclear tests is of primary importance for impacts on environmental issues. The recent blast on September 3, 2017 has been in question due to its potential destruction on the global environment. Here, we applied a method of full moment-tensor inversions to analyse broadband waveforms generated by such an explosion. The signals were recorded by a network of 4 regional seismic stations (MAJO, INCN, MDJ, BJT), situated between 360 and 1,100 km away from the explosion epicenter. The results showed that a variance reduction of 72.6%, providing high confidence for all values obtained from the method used: a seismic moment of Mo
= 6.25 · 1024 dyne cm, corresponding to a moment magnitude of M
w = 5.8, with a dominant volumetric component (ISO) of 50% relatively compared to a 6.8% double-couple (DC) part and a 43.2% compensated linear vector dipole (CLVD) part, and a centroid-depth of 1.0 km. The relative dominance of the ISO seismic component over the other two components, along with the shallow source extracted from the cross-correlation and source mechanism analysis, suggests that the September 3, 2017 explosion was induced by a suspected nuclear test.
Simple Glucose Measurement System Based on Uncladded Fiber Bragg Grating Etched with Nitric Acid
Authors: Asnawi  , Rahmawati E , Qomariyah N , Siddiq N A , Goshals S K , Pramono Y H
Published: December 2019

The demand for a non-invasive, fast, and accurate glucose detection for diabetic patients is increasing nowadays. It is predicted that diabetic patient will increase from 415 million people at 2018 to 640 million people at 2050. Glucose is also present in saliva, therefore glucose concentration measurement in saliva can be an alternative way during diabetics monitoring. In this study, we measure 0-60% glucose concentration through optical systems. The optical system consists of an erbium-doped fibber laser, uncladded fiber bragg gratings that have been etched with nitric acid (HNO3), and optical spectrum analyser (OSA). The measured parameter is a Bragg wavelength shift due to changes in glucose solution concentration. The results show that the wavelength shifts to lower value (blue shift) as the glucose concentration increases. The sensitivity obtained from this measurement system is 1.2 pm/% in glucose solution. This result is a preliminary study to detect glucose concentration in saliva based on Fibber Bragg Grating which has advantages for diabetic patients such as simple setup, non-invasive, fast, and low cost.
Development of Optical Fiber Sensor Performance as a Tool to Determine Cholesterol Concentration
Authors: Budiyanto M , Purnomo A R , Sabtiawan W B , Suhariningsih  , Yasin M
Published: December 2019

The purpose of this study was to determine cholesterol concentration by developing the performance of optical sensors. The use of this optical sensor is equipped with an optical fiber bundle to guide the wave in the hope of not reducing the intensity of the wave source. This sensor is simpler and inexpensive to use to determine the concentration of a material. The research method for determining cholesterol levels can be determined through the character of the laser beam to the material through a fiber optic sensor. The optical fiber sensor method is simpler and cheaper to use to determine the concentration of a material. Based on this description, research on fiber optic sensors will be developed as an instrument model to determine cholesterol concentration using a fiber optic bundle type sensor. The method used is the modulation of laser beam intensity. A beam of light that enters the optical fiber of the receiver and is processed by an optical detector into an electrical signal that will be displayed on the computer. The experimental results will obtain a linear relationship between the sensor output peak voltage as a function of variations in cholesterol concentration and parameters and sensor performance will be measured including sensitivity and linearity. The results showed that maximum voltage detection showed a linear decrease with increasing concentration with a sensitivity of 0.15 mV/ppm and a linearity of more than 97%. high sensitivity, simplicity of design, and low cost of promoting the developed sensor results in good performance detecting cholesterol concentration.
A Water Surface Cleaning Robot
Authors: Rahmawati E , Sucahyo I , Asnawi A , Faris M , Taqwim M A , Mahendra D
Published: December 2019

This paper describes the design of a robot for cleaning rubbish floating on the water surface. Three important issues for designing the aquatic robots are a cost-effective solution along with robustness and durability. Due to the nature of the cleaning work, we designed the vehicle structure that can provide high stability, good ability in maneuver and can easily collect all the waste flowing in between. A pontoon shaped hull works best for this case and fulfils all the hydrostatic, structural stability criteria. For removal and collection of surface waste, a motor-driven collecting-arm system has been designed for collecting the wastes and redeploying it into a rectangular basket on the hull. This design provides simple and effective waste removal and accommodates large amounts of waste within a small space. For the prototype, the hulls were made up of styrofoam which is wrapped by fibre and then coated with waterproof and resin. It supported together by aluminum. This light and tough structure support the total weight of the system. The propulsion system based on a differential drive mechanism has been designed, which allows the robots to take a 360 turn on the spot and provides high thrust. Electronic circuit and motors have been placing inside the hull, in order to protect them from water. The robot is manually controlled by remote control based on Xbee Pro wireless modules. The testing of the robot prototype proved to be effective in waste collecting and removal. The maximum trash loads that robot can bear is up 16 kg.
Multinomial Logistic Regression and Support Vector Machine for Osteoarthritis Classification
Authors: Aroef C , Yuda R P , Rustam Z , Pandelaki J
Published: December 2019

Everyone joints go through a cycle of damage and repair during their lifetime, but sometimes the body’s process to repair our joints can cause changes in their shape or structure. When these changes happen, it’s known as osteoarthritis. Osteoarthritis is the most common form of arthritis, affecting millions of people worldwide. Osteoarthritis causes pain, swelling, stiffness in the areas, and decreased the ability to move for the sufferers. Therefore it requires accurate method of classification. Many methods have been used to classify osteoarthritis, but this study will apply Multinomial Logistic Regression and Super Vector Machine (SVM) as the machine learning methods. We used CT scan result data from RSUPN dr. Cipto Mangunkusumo, Central Jakarta. The results show the SVM provides better results than Multinomial Logistic Regression in terms of classification accuracy. The highest accuracy of SVM reaches around 85%, while Multinomial Logistic Regression only 71%.
A Split Plot Design for an Optimal Mixture Process Variable Design of a Baking Experiment
Authors: Sitinjak Mika Alvionita , Syafitri Utami Dyah , Erfiani
Published: December 2019

A mixture process variable (MPV) design consists of mixture design and process variable(s). The problem in MPV experiment is the number of experiment runs will be larger if the process variable increases. An optimal design can be a solution to produce a good design with a certain criterion and a limited number of runs. In practice, the compositions of the mixture design are running on each level of the process variable(s). It has a consequence that the randomization is restricted. A split-plot design can be an alternative to overcome the problem. In this research, the whole plots of the split-plot design were the levels of the process variable(s) and the subplots were the compositions of the mixture experiments. In addition, two optimality criteria were used: D-optimality and I-optimality criterion. The D-optimal design is searching a design by minimizing covariance of model parameters meanwhile the I-optimal design is seeking a design by minimizes average of the prediction variance. The study case was a baking experiment in which consisted of three flours and a process variable. It is surprised that the D-optimal design out performed compared to the I-optimal design in terms of the variance prediction in this case.
Analysis between Temperature and Wind Speed in East Java using Bivariate Extreme Value Theory
Authors: Oktaviarina A , Sofro A
Published: December 2019

Extreme weather now is the biggest effect of climate change. It is also a major issue over the past decade. High heat and hurricanes are some of its indicators. Both natural disasters have a big impact not only on humans but also on the presence of animals and the environment. Therefore, modelling of the disaster, especially for prediction extreme events is the basic need to minimize the damage and the losses. Both of the hazards come from extreme temperatures and wind speeds, respectively. Hence, this paper will analyze the issues using extreme value theory (EVT) approach. We will investigate it separately and then analyze both two cases simultaneously. The results show that using peaks over threshold univariate or separately approach is the best model among other approaches since providing the smallest AIC value. Meanwhile, the value of AIC for the block maxima is smaller than peaks over threshold using the bivariate approach.
The New Convergence Definition for Sequence of k-Dimensional Subspaces of an Inner Product Space
Authors: Manuharawati  , Yunianti D N , Jakfar M
Published: December 2019

We discuss the convergence for sequence of subspaces of an inner product space. This paper is an extension of the work by Manuharawati et al [10 and 11]. In this paper, we present a concept of convergence of sequence of k-dimensional subspaces of an inner product space. The properties of the concept are established. Moreover, we also study its connection with angles in an inner product space.

Mathematics Subject Classification 2000: Primary 40A05; Secondary 14M15, 15A63, 46B20
Stability and Numerical Simulation of Prey-predator System with Holling Type-II Functional Responses for Adult Prey
Authors: Savitri Dian
Published: December 2019

In this paper, we analyze the local stability of the prey-predator model. This model was constructed from two prey involving stage-structure and one predator. The population of prey is divided into two subpopulations, adult prey and immature. The ratio of intrinsic growth of predator population density divided by adult prey conversion factors into a predator. Reduction of predator populations has a reciprocal relationship with the availability of favorite foods determined by the environmental resources. We also consider that Holling type II the functional response for the predator. We have investigated the local stability and the solution of the system. We have studied the existence and feasibility of various equilibrium points. The system has three positive equilibria, namely the original, the extinction of the predator and the interior point. We explore the stabilities of all nonnegative equilibrium point by the real parts of the eigenvalues of the Jacobian matrix at each equilibrium point must be negative. We also use the Routh-Hurwitz criterion to investigate the stability at the interior equilibrium point. This study aims to detect the limit cycle with its phase portrait and its time-series graphs of the prey-predator system. Numerical simulated are represented as phase portraits to draw the stability of the equilibrium point. In our Numerical outcomes confirmed the analytical results and the local behavior prey-predator model which start from their positive initial condition. The parameter value is taken mainly from the literature and assumption. By a computational Python using the fourth-order Runge-Kutta method, we solved the prey-predator system and showed some new phase portraits such as the existence of the stable or unstable equilibrium point under a suitable value of the parameter. The next research, we will explore the global stability analysis behavior of the interior equilibrium point.
Estimation of Super Pairwise Alignment (SPA) parameters on zika virus mutation using Artificial Bee Colony
Authors: Rahmalia D , Rohmatullah A , Pradana M S
Published: December 2019

There are many diseases caused by viruses or bacteria. The structure of virus and bacteria always mutate to create new structures. Sequence alignment is important so that it can be used to research genetic diseases and epidemics. In this reseach, we take case study of zika virus. To see the similarity between original virus and the mutation virus, it is required the alignment process of two virus sequences. The method used for aligning two virus sequences is Super Pairwise Alignment (SPA). Due to the value of objective function depends on SPA parameters, in this research we will apply heuristic method, such as Artificial Bee Colony (ABC) algorithm to optimize SPA parameters minimizing penalty value or maximizing similarity value as objective function. ABC is the optimization method which is inspired by the behaviour of bee colony in which the advantages are there are three types of bees that will update optimal solution in approaching. From the ABC simulations, we can obtain optimal SPA parameters resulting minimum penalty value or maximum similarity value between two aligned zika virus protein sequences in approaching.
Magnetic property approach for identification of dominant crystal structure in AISI420 treated by RF-DC Plasma N2-H2
Authors: Herdianto H
Published: December 2019

The nitridation of RF-DC plasma N2-H2 into AISI420 produces several phases namely α’ (bcc),ε (hcp), and γ (fcc) which are randomly distributed in a number that is difficult to identify. So the most dominant justification of crystal phase was needed. Based on the concept of isothermal transformation of AISI420 transformed from the α’ phase (ferromagnetic), to ε phase (paramagnetic), and to γ phase (nonmagnetic). It can be used as the underlying theory that magnetic property approach can potentially identify the dominant crystal phase. This study measured the magnetic properties of AISI420 treated by RF-DC plasma N2-N2 for identification of dominant crystal structure. Based on the hysteresis curve (M-H loop) of VSM method, magnetic characteristics can be produced such as susceptibility. Furthermore, the atomistic simulations were performed with the LAMMPS. Modelling of schematic picture of the structure using VESTA v.3.3.2 64 bit. Susceptibility value of AISI420 treated with RF-DC Plasma N2-H2 is range in the notation of 10-5 to 10-3, so it meets criteria of 10-5 ⩽ 10-3 which can be categorized as paramagnetic and super-paramagnetic. It has the dominant ε-Fe3N phase with trigonal-hcp microstructure based on magnetic property approach and simulations of LAMMPS and VESTA.
The Potency and Food Safety of Lamp Shells (Brachiopoda: Lingula sp.) as Food Resources
Authors: Ambarwati R , Rahayu D A , Faizah U
Published: December 2019

Lamp shells is one of primitive brachiopods that can be found in the tropical region. One species of brachiopod has been reported found in Indonesia. This invertebrate is collected by local people for consumption as well as traded in the local market in the area of the southern shore of Madura Island and the northern shore of East Java, Indonesia. This research aimed to analyze the potency of lamp shells as food resources based on the protein and fat content and to evaluate the food safety based on the content of lead (plumbum) and cadmium. The sample of lamp shells was collected from Probolinggo beach. Fresh samples of flesh and pedicle of lamp shell were kept in a cool box for laboratory analysis. The protein content was analyzed using Kjeldahl method, while the content of fat was analyzed using soxhlet method. In addition, the level of plumbum and cadmium in the flesh and pedicle of lamp shell were tested using atomic adsorption spectroscopy. The results revealed that both of the flesh and the pedicle of lamp shells contained protein, namely 14.02±0.62% and 12.06±0.44% respectively. The flesh contained 1.12±0.13% of fat, meanwhile, the pedicle contained 0.84±0.07% of fat. These nutrient content were comparable other marine invertebrates. It seems that the nutrient content outweighs the content of heavy metal that can be accumulated in the sessile invertebrate. The content of plumbum in the flesh and pedicle of lamp shells were 0.10±0.01 ppm and 0.08±0.01 ppm respectively. Meanwhile, the content of cadmium in the flesh and pedicle of lamp shells were 0.09±0.01 ppm and 0.06±0.01 ppm respectively. These numbers are considerably lower that the level permitted. Hence, it can be concluded that lamp shells has potency as food recources.
The Content Validity of Digital Test Items for Evaluation Courses Based on Superitem-Wondershare Using Aiken’s Calculation
Authors: Divayana D G H , Adiarta A , Sudirtha I G
Published: December 2019

The digital test item for evaluation courses that is designed with tiered arrangements use super item concept and is showed digitally use the Wondershare application makes it easy for students to practice the quality of their critical thinking in working on test questions whenever and wherever they are. But to get the good quality test items, then it is still necessary to test the item validity properly and accurately. The method that can be done to determine the valid test items is through calculating the validity of the items uses the Aiken model. Based on those matters, the purpose of this study was to show the calculation process of the test items validity uses the Aiken model. Subjects that were involved in the calculated process the validation of each test item were four experts, including two experts in the field of evaluation and two experts in the field of informatics engineering. The tool was used to assess the test items was a questionnaire consisting of 42 question items. The method used to analyze the test items was by comparing the results of the test item validation used the Aiken model with the validation classification according to Guilford. The study results were showed that from 42 test items tested; there were two invalid items and 40 valid items.
Statistical reasoning or statistical method: Students’ preferences for learning Statistics
Authors: Kusumarasdyati
Published: December 2019

Statistical reasoning should precede the statistical method in the teaching of statistics because the students should master the concepts before they perform computations. To find out whether the students were aware of this principle, the present study explored their preference and the underlying reasons. Twenty undergraduates were taught central tendency and variability by using statistical method (with machine computation) and statistical reasoning (with manual computation) respectively in one session. Most of them turned out to prefer to reason and compute numeric data manually because they understood the statistical concepts and the process of the computation. On the other hand, the rest of the undergraduates preferred the teaching of statistics using the statistical method with machine computation for three reasons: accuracy, efficiency, and convenience. The implications of these findings for the teaching of statistics were presented.
Ancient China history-based task to support students’ geometrical reasoning and mathematical literacy in learning Pythagoras
Authors: Fachrudin A D , Ekawati R , Kohar A W , Widadah S , Kusumawati I B , Setianingsih R
Published: December 2019

This study aims to identify the potential learning opportunities provided by ancient china’s geometric diagram introduced by Liu Hui into student task in learning Pythagorean theorem. We investigate the role of the history-based task, from Nine Chapter, in supporting students’ mathematics literacy and geometrical reasoning. Design research was chosen as a method to reach the purpose. Our discussion is limited only from a part of one phase, namely pilot experiment, from three main phases of design research. This research was conducted at three different Junior High schools in Indonesia. The instructional activities were designed based on history-based problem-solving. The analysis was focused on students’ learning process, and specifically, the results of their visual reasoning and mathematical literacy. The result indicated that the use of figures or diagrams, with written information act as a support for performing algebraic calculations for students who are unfamiliar using symbol or algebraic operation. In this way, by using geometric manipulation, a new figure is arrived at on which the solution can now be read easier. Furthermore, by using history-based context, students got more opportunities to improve their performance in mathematics literacy by formulating various contextual mathematics problem, sourced from history, into mathematical form.
Student’s Mathematical Representation in Solving Geometry Problems Based on Cognitive Style
Authors: Adnan S , Juniati Dwi , Sulaiman Raden
Published: December 2019

This research aims to describe the student’s mathematical representation of junior high school who had field independent cognitive style and field dependent in solving geometry problem. Subjects were selected based on the test results of the Group Embedded Figures Test (GEFT), and had equivalent mathematical abilities. The research subjects consisted of two female students who had field independent and field dependent cognitive style. This research uses a qualitative method. The results showed that the subject used mathematical representation in expressing his idea to solve geometry problems by using Polya’s problem solving. The mathematical representation of field independent in solving geometry problem is: understanding information and what is asked in verbal, devising a plan in a visual of geometric images, then presenting verbal plans, carrying out the plan in symbolic by doing calculations, and looking back in symbolic by doing recalculation. Where as field dependent mathematical representations to solving geometry problems is: understanding information and asking in visual of geometrical images and verbal, devising a plan in a visual in the form of subsequent images presenting verbal plans, carrying out the plan in symbolic by performing calculations, and looking back in symbolic in the form of recalculation.
Student’s Multiple Representation in Solving Addition and Subtraction of Fraction Problem
Authors: Yuliani T W , Fuad Y , Ekawati R
Published: December 2019

Fraction is one of mathematics’ topics that difficult to be understood. Many representation form from fraction. Representation has an important role in mathematic. Representation helps student to create mathematic ideas more concrete. So, multi-representation is needed in fractional problem solving. This study is to describe students’ ability of multi-representation in solving fraction problem. The sample of this study is the VII-B grade students of a state junior high school in Munjungan city, East Java. There are eight classes from A to H, VII-B was chosen purposively. There were 10 boys and 12 girls in VII-B. Multi-representation test was given to each student. Three volunteer were chosen as our respondents. The semi-structured interview was utilized to investigate the process and students conceptual of fraction. This study shows that the students still have difficulties to represent fraction. The students were success to solve model representation, but they have difficulty to solve fraction in number line. The error in representation on addition and subtraction of fraction problem shows that student did not understand fraction concept well. Student ability on multi-representations should be conducted through exercise continually.
Relationship of Teacher’s Content Knowledge on Fraction Topic Toward Student Performance
Authors: Kutub A H W , Wijayanti P , Manuharawati
Published: December 2019

The aim of this study was to describe the relationship between teacher content knowledge and student performance in Fraction. This study used the mixed method that provided Content Knowledge test for fifteen teachers who taught the seventh class. The test consists of multiple choices to measure facts and procedures, knowledge of concepts and relationships, and knowledge of generalization. The study was divided into two phase, Quantitative phase and Qualitative phase. The Quantitative phase, teachers were mapped in two different levels, low and high based on score of Content Knowledge test. Two samples were classified into low level and high level. Furthermore, two groups/classes of the teacher samples were analyzed using Chi-Square test to investigate the relationship between teachers and student performance. The Qualitative phase of the study were included into three stages: (1) teacher interview, and (2) Student Problem solving, (3) description of the relationship of teacher’s content knowledge and student learning performance. The results of the study showed that the Teachers content knowledge in Fraction were affected to student performance, in addition, there were also similarities in the pattern of student performance tests on fraction and the teacher’s answers based on the results of the CK test.
Creative Mathematical Reasoning of Prospective Teachers in Solving Problems Reviewed Based on Working Memory Capacity
Authors: Palengka I , Juniati D , Abadi
Published: December 2019

Reasoning requires logical thinking in solving problems, and working memory capacity becomes something important. This study aimed at investigating the creative mathematical reasoning of prospective teachers in solving problems reviewed based on working memory capacity. This research was qualitative. The study conducted at Indonesian Christian University of Toraja to Mathematics Education study program students. The selection of research subjects was done by giving operation span (O-SPAN) assignments to select 1 student with a high category of working memory capacity and 1 student with a low category of working memory capacity. Then they were given a creative mathematical reasoning test and interview. Based on the data analysis, it obtained that the creative mathematical reasoning of prospective teachers in solving problems on the research subject who had low working memory capacity showedcreativityandplausibilitycriteria but it did not showanchoringbecause he could not provide arguments that supported the selection of strategies based on mathematics. Furthermore, creative mathematical reasoning of prospective teachers in solving problems on the research subject who had high working memory capacity met the three criteria for creative mathematical reasoning, namelycreativity, plausibility and anchoring.
Student Teachers’ Construction of Mathematical Theorem of Set and Cardinality
Authors: Palupi Evangelista Lus Windyana , Rosyidi Abdul Haris , Putri Hani Rizkia
Published: December 2019

Constructivists suggest that teachers should guide and facilitate their students in reinventing and or reconstructing mathematics concepts as in reconstructing a theorem. A theorem in mathematics holds a vital role as a fundamental aspect in building the mathematics itself. Hence, students must learn and acquire this ability. Furthermore, by reconstructing a theorem, students not only learn about the theorem but also learn about problem-solving since the theorem that should be reconstructed can be presented as a problem. In which, this skill is needed and promoted in the 21st century. Hence, the teacher has to be able to reconstruct and prove their construction of theorem. However, many studies were focused on investigating students’ mathematical proof ability, not on the ability to reconstruct a theorem. This study is aimed to investigate mathematics undergraduate students’ ability to reconstruct and prove a theorem. A problem to make a general statement regarding the numbers of all possibility of the cardinality of A B, with A, B is set, and n(A) is a and n(B) is b, is given to 60 undergraduate students who are majoring mathematics education. The statement then is analyzed and categorized into 0 to 5 based on the developed framework. The result shows that most students’ answers (29 answers) are categorized as an incomplete or irrelevant theorem (level 0), while only seven answers can be categorized as level 5 (well structured). As for level 2, 3, and 4, there are 13, 8, 3 answers representatively. Also, there is no student answer, which is categorized as level 1. The mistakes occur because students do not fully understand the mathematics notion. Then, the theorem made is different from the one that is asked, the given condition mentioned by the students is not general enough (does not represent all cases); the conclusion made is false. However, no conclusion is unrelated to the condition.
The Performance of Prospective Teachers in Interpreting Graphs on context-based tasks
Authors: Hidayat D , Siswono TYE , Hartono S , Prihartiwi NR , Kohar AW
Published: December 2019

Graphing ability facilitates students to understand and to connect graphs of data with real-world situations. This ability related to mathematical competencies such as logical thinking and visual representation. One aspect of graphing ability that is important for the student to get meaning from the graph is the interpreting graph. The purpose of this study is to investigate the performance of prospective teachers in interpreting graphs on context-based tasks. This study uses a descriptive-explorative method involving 24 prospective teacher participants at the Universitas Negeri Surabaya. This article presents the performance of prospective teachers’ interpreting graph abilities based on five levels of graph interpretation by Aoyama. The prospective teachers’ graph interpretation is explained along with the difficulties.
The Effectiveness of the Methods and Approaches of ESD for 2030 Sustainable Development Goals; From Analysis of the Questionnaire Survey to the School Teachers
Authors: Icihnose T
Published: December 2019

ESD is a key element of quality education. Its cross-cutting competencies in cognitive, socio-emotional and behavioural dimensions of learning bear relevance to all areas of education. (UNESCO Executive Board 20 February 2019). This study, the result of four years of research in 279 primary and secondary schools in Japan, reveals that in integrated study periods, and with the engagement of local human resources, an increase of activities across different classrooms and grades are a clear result of enhanced ESD and students’ collaboration, cooperativeness, cooperative attitude, and ability to communicate are interconnected. From a pluralistic perspective of ESD, teaching students to confront tensions and conflicts and tackling issues with no single answer seems to be difficult. Since the ESD curriculum has been constructed through whole-school educational activities in Japan by linking it with other subjects and areas, utilizing integrated study periods, it is important to examine approaches to understanding the effectiveness of a whole-school approach of ESD.
Understanding the Nature of Science Through a Content Analysis of Dynamic Fluid: Voices of Pre-Service Physics Teachers
Authors: Suprapto N , Mubarok H , Adam A S
Published: December 2019

Understanding the Nature of Science (NOS) is useful for pre-service, novice, and senior teachers. The specific purposes of this research were analysing the reasoning of NOS among Pre-service Physics Teachers’ (PSPTs) regarding the fact, concept, principle, hypothesize, law, and theory of dynamic fluid, and analysing these NOS variables based on gender, GPA, and score of Philosophy of Science course. This research utilised a mixed-method study, descriptive-interpretive approach with supporting by quantitative analysis of the NOS in relating to PSPTs voices on dynamic fluid. A content analysis was considered in helping the researcher to better comprehend the process of constructing meaning. The study involved of a written questionnaire and followed by a semi-structured interview. A number of thirty one (31) PSPTs in public university in Surabaya, Indonesia were invited to complete the questionnaire form and joined a semi-structured interview. The PSPTs’ voices were categorised into four levels: dissatisfied (naïve), intelligible, plausible, and fruitful that represents the levelling of reasoning. The findings indicated the distribution of PSPTs’ reasoning in dynamic fluid concept varied from the level of dissatisfied to fruitful. PSPTs female performed better in reasoning of NOS than male of dynamic fluid. Moreover, PSPTs whose GPA is better also performed better in reasoning of NOS. Finally, the score of course had also in line with the level of reasoning of NOS.
University Students’ Misconception in Electromagnetism
Authors: Bestiantono D S , Sa’diyah E H , Rachmatya R , Mubarok H , Adam A S , Suprapto N
Published: December 2019

This aim of the research was to analyse the university students’ conception of electromagnetism. This research used a mixed-method design, the combination of a quantitative and qualitative method. For the quantitative part, the research utilised a conception test of electromagnetism, for the qualitative part, the research focused on the descriptive analysis that generated by the university students. The participant in this research was 15 physics students from 9 different classes in the Physics Department of a national university in East Java Indonesia. A conception test included ten different multiple-choice problems and followed by the descriptive analysis of these problems. The participants asked to choose the right answer and write their reasons or arguments that support their answer. In this study, the test was given without giving any treatment for the participant. The analyse method that used in this research was the quantitative and qualitative description. The result showed that the conception of students ranged between 2nd semester (freshman) and 4th Semester (sophomore) in the physics department. Therefore, it is concluded that the students have electromagnetism misconception.