bluuebunny/crossref_metadata_2025 huggingface dataset:
The analysis of the implementation of project based learning and its influence to the student deductive reasoning based on cognitive style on solving super edge local antimagic total labelling
Authors: Karimah M , Dafik  , Tirta I M , Wangguway Y , Jabbar Z L A
Published: June 2020

In this study, we tried to test students’ deductive reasoning based on cognitive style in the application of super edge total local antimagic labels by applying Project Based Learning (PjBL) learning models. This study uses a mixed method, namely qualitative methods and quantitative methods. The research subjects consisted of two classes, namely 28 control class students and 30 experimental class students. The instruments used in this study were pretest, posttest, observation sheet, and interview sheet. Before the research activities, we tested the homogeneity of both classes using the results of the pretest. Homogeneity test results show the sig value is 0.481> 0.05, so the average difference between the two classes is not significant. This shows that both classes are homogeneous or have the same ability. Next, we also discuss the normality of using posttest data. This shows that the independent sample test on the posttest data from the control class and the experimental class obtained a sig score of 0.657 <0.05, so that it was significant which meant the difference between the control class and the experimental class. While the effect of punishment increases based on students’ cognitive style, it shows that 52% are in the very high category, 31% depend on the high category, 13% depend on the average category, and 4% depend on the low category. Project-Based Learning Model (PjBL) and the influence of deductive reasoning based on students’ cognitive styles in the super edge study of total local antimagic labeling.
The analysis of algebra creative thinking skill based on strong mathematical habit of mind
Authors: Nugroho S W P , Riyadi  , Triyanto
Published: June 2020

This research aimed to describe the student’ creative thinking skill of two variables on linear equations system viewed from the strong mathematical habit of mind. The indicators of creative thinking skill include fluency, flexibility, and novelty. This research was a qualitative descriptive study. The subjects of this research were 7 students of IX A class at SMP N 4 Playen Gunungkidul. The data collection methods were a questionnaire, test, and interview to discover the students who had strong mathematical habit of mind. The research instruments had been validated by using triangulation method. The result showed that there were 2 students (2 8.58%) conformed with fluency indicator (it was categorized as less creative), there was 1 student (1 4. 2 8 °%o) conformed with flexibility indicator (it was categorized as adequate creative), and there were 4 students (5 7. 1 4°%o) namely 3 students conformed with fluency and flexibility indicator and student conformed with the indicators of fluency and novelty (it was categorized as creative). The analysis showed that the students who had strong mathematical habit of mind still there in the students who had less creative. There was no students who had strong mathematical habit of mind in the students who had very creative thinking skill. This was caused by the difficulty of students in turning contextual questions into mathematical sentences and lack of confidence in using various ways to solve the problems. The students tended to use some procedural steps in solving the problems. Therefore it was necessary to emphasize a good understanding of algebra concept and the practice of varying questions so that the students were not mistaken in using algebraic concepts and had no difficulty in solving non-routine algebraic questions.
Students’ mathematical communication abilities in solving geometry problems viewed from learning styles
Authors: Sholihah A N , Riyadi  , Triyanto
Published: June 2020

The purpose of this research is to describe student mathematical communication abilities in solving the problem of material transformation (reflection and rotation) in terms of student learning styles. This research is a qualitative descriptive study. The subjects consisted of 6 classes of IX students in Wonogiri 7 Junior High School who were selected by purposive sampling. Data collection tools used were written tests of communication abilities and questionnaires to categorize students based on their learning styles and interviews. The data validity of the data used triangulation method. Analysis of this data shows that the communication of visual students can meet indicators: 1) Reflecting and answering about mathematical concepts; 2) Connecting daily news with language mathematics symbols; 3) Expressing and evaluating into mathematical theory; 4) Using mathematical opinions to make detailed conjectures. The mathematical communication of the auditory students can meet the indicators: 2) Connecting daily news with language mathematics symbols; 3) Expressing and evaluating into mathematical theory; 4) Using mathematical opinions to make detailed conjectures. The mathematical communication of kinesthetic students can meet indicators: 1) Reflecting and answering about mathematical concepts; 3) Expressing and evaluating into mathematical theory. This shows that dominant students have mathematical communication abilities with visual learning styles caused by students who were being able to communicate their mathematical ideas connected in their daily lives.
Investigation of the students’ number sense in seventh grade
Authors: Marga S A , Kusmayadi T A , Fitriana L
Published: June 2020

2013 curriculum is the latest center of attention, especially in emphasizing the students’ understanding in learning mathematics not just only counting. The students understanding especially about these numbers can be seen from the students’ ideas to solve a problem. The students’ skills in solving the problem can be seen from their sensitivity to the numbers. This number sense ability can help the students’ performance by using some strategies that are useful for solving problems. Therefore, this study aimed to know the extent of number sense component possessed by VII H students at SMPN 3 Ponorogo. The subjects in this research were 30 students. The data collection used in this research was written number sense test result. This research was a qualitative descriptive study. The data that was obtained in this research such as the description of students’ number sense. The results indicated the ability of students based on component number sense, the lowest component number sense in recognizing the relative size of number and the students’ ability to decide wisely the strategies used from the calculation results. Overall, the average of students’ numbers sense was 50.78. Thus, it could be concluded that the ability of number sense that possessed by VII H students could be categorized as medium. However, the results of students’ work were still dominated by procedural understanding. The often problem faced by students were the lack knowledge about numbers concepts, the students used procedural ways, and the students did some errors in calculations.
Mathematical connections ability of junior high school students viewed from mathematical resilience
Authors: Rohmah S , Kusmayadi T A , Fitriana L
Published: June 2020

The mathematical connections ability is the ability to link between topics in mathematics, between mathematics with other disciplines and between mathematics and life. This study discusses about designing mathematical connection skills in terms of students’ mathematical resilience involving 31 students 8th grade students as research subjects. The method used in this research is descriptive method using qualitative. The research instruments used were mathematical resilience questionnaires and essay tests. The results of this study indicate for students who have high resilience, student success in recognizing and using relationships between mathematical ideas (70.31%), students’ success in understanding the relationship of mathematical ideas (80.15%), and student success in recognizing and applying one mathematical content to another mathematical content (83.33%). Students who have moderate resilience, student success in recognizing and using relationships between mathematical ideas (48.04%), students’ success in understanding the relevance of mathematical ideas (40.28%), and student success in recognizing and applying one mathematical content to another mathematical content (40.28%). Students who have low resilience, student success in recognizing and using relationships between mathematical ideas (35.94%), student success in understanding the relationship of mathematical ideas (39.71%), and student success in recognizing and applying one mathematical content to another mathematical content (37,5%).
The SOLO taxonomy: classify students’ responses in solving linear program problems
Authors: Claudia L F , Kusmayadi T A , Fitriana L
Published: June 2020

The aim of this study is to classify students’ responses in solving mathematical problems. Using the taxonomy by Biggs and Collis in 1982, called taxonomy is SOLO (Structure of Observed Learning Outcomes). In the SOLO taxonomy, there are five levels of students’ responses, such as pre-structural, uni- structural, multi-structural, relational, and extended abstract. Every student has different abilities, one of the ability is to understand mathematical concepts because sometimes students make misconceptions that result in students not being able to solve mathematical problems correctly. The concept in a linear program problem is that students can change story problems into mathematical modeling after that student can solve with the procedures that have been learned. This study used descriptive qualitative research and the selected of subjects is senior high school students in the City of Kediri and then used purposive sampling techniques. One of the chosen class consisting of 35 students was selected 5 students to represent each level of SOLO Taxonomy. The results from this study are: (1) Pre-structural level: Students cannot process information properly, (2) Uni-structural level: Students do not make the most of available information, (3) Multi-structural level: Students understand one concept which is example with variables and can model mathematics, (4) Relational level: Students can process information appropriately, and (5) Extended abstract level: Students can understand concepts well. With the levels of students’ response can be known to what extent students understand mathematics so they can solve mathematical problems.
NanoSQUIDs based on Nb nanobridges
Authors: Rodrigo R. , Faley M.I. , Dunin-Borkowski R.E.
Published: June 2020

We have developed nanoSQUIDs with Josephson junctions in the form of Nb nanobridges, whose thickness, width and length are in the order of the superconducting coherence length in Nb thin films, which is 15 nm at 4.2 K in 20-nm-thick films. The thin Nb films were deposited using pulsed DC magnetron sputtering. A 30-nm-thick mask of PMMA resist was formed by electron beam exposure using a dose of 50 mC/cm2 at 100 kV, at which PMMA operates as a high-resolution negative resist. Compared to the previously used HSQ resist, PMMA has a much better availability, lower health risk, a longer shelf life and a simpler development procedure, while maintaining sufficient resolution. Both Nb nanobridges with widths down to 10 nm and nanoSQUIDs with the incorporated nanobridges were fabricated using reactive ion etching with pure SF6 gas. They show non-hysteretic I(V)-characteristics and a modulation of the critical current at both directly injected or externally applied magnetic field fluxes. The obtained spin sensitivity of

S
n

1
/
2

≅
135

μ
B

/
√
H
z

is very promising for the use of the nanoSQUIDs as magnetic field sensors for the investigation of nanoscale objects.
Optimal SQUID Loop Size in Arrays of HTS SQUIDs
Authors: Crété Denis , Lemaître Yves , Marcilhac Bruno , Recoba-Pawlowski Eliana , Trastoy Juan , Ulysse Christian
Published: June 2020

Arrays of Superconducting interference devices (SQUIDs) deserve much attention for high frequency magnetic field detection because of the combined advantages of wideband radiofrequency operation and improved dynamic range compared to single SQUID magnetometers. Indeed, in principle the dynamic range should scale as the square root of the number of SQUIDs. It is well-known that the size of a SQUID designed for magnetometry has an optimum resulting from a trade-off between large magnetic flux in its loop and small loop inductance. Among the factors affecting this optimum when using arrays of SQUIDs, we discuss the impact of Josephson junction characteristic dispersion, experimentally observed with high temperature superconductors (HTS) and wideband requirement. Both limit the SQUID size to lower values, in particular for arrays of SQUIDs connected in series.
Design, Performance and Cabling Analysis of Nb3Sn Wires for the FCC Study
Authors: Hopkins Simon C , Baskys Algirdas , Bordini Bernardo , Fleiter Jerome , Ballarino Amalia
Published: June 2020

The hadron collider proposed by the Future Circular Collider (FCC) study would require high-field superconducting magnets capable of producing a dipole field of around 16 T in a 50 mm aperture. To develop a suitable conductor for these magnets, CERN is coordinating a conductor development programme aiming to obtain Nb3Sn wire with a non-copper critical current density of 1500 A mm−2 at 16 T and 4.2 K, in lengths suitable for manufacturing 14 m long magnets, and able to withstand cabling without significant degradation. Here we report the superconducting characterisation and quantitative microscopy of recently-developed Nb3Sn wires with novel layouts and compositions, and evaluate their suitability for Rutherford cabling based on cabling trials and rolling studies. An analysis of the influence of wire layout, materials and mechanical characteristics on cabling performance is presented, to support recommendations for future wire designs.
Microwave investigation of pinning in Te- and cubic-BN- added MgB2
Authors: Alimenti A. , Torokhtii K. , Grigoroscuta M. , Badica P. , Crisan A. , Silva E. , Pompeo N.
Published: June 2020

MgB2 has great potential for many applications, thanks to its relatively high critical temperature and low fabrication cost. Large efforts are done to improve the current carrying capabilities of bulks and tapes in view of different application fields, e.g. with the addition of Te and cubic-BN to MgB2. To elucidate the vortex pinning physics exploiting a different dynamic regime, we present here a microwave study of the pinning properties of spark plasma sintered bulk MgB2 with and without the addition of 0.01 % at. Te or cubic-BN. We show the surface resistance Rs
of the MgB2 samples measured with a dielectric-loaded resonator at ~ 16.5 GHz and ~ 26.7 GHz in the 10 K-Tc temperature range at fields up to 1.0 T. Then, the MgB2
Rs
is studied with high frequency vortex motion models in order to obtain the pinning constant (Labusch parameter) and the depinning frequency. Finally, the microwave behavior of MgB2 in the mixed state is compared with the recent results obtained on Nb3Sn.
Correlations between the structure and superconducting properties of MT-YBaCuO
Authors: Prikhna T A , Moshchill V E , Rabier J , Chaud X , Joulain A , Pan A V , Litskendorf D , Habisreuther T.
Published: June 2020

Comprehensive experimental results of fully oxidized (up to YBa2Cu3O6,9-7) melt-textured YBaCuO materials with different microstructures are presented. These microstructures are built respectively: (1) with a high dislocations density but almost without twins (after high temperature treatment at 2 GPa) and (2) with a high twin density, but practically free from dislocations and stacking faults (after high temperature oxygenation at 10-16 MPa). It is shown that for attaining high critical current densities and fields of irreversibility (jc(H‖c, 0 T)=9·104 A/cm2, H
irr=9.7 T at 77 K), a high twin density in YBa2Cu3O6.9-7 matrix of MT-YBCO is required. The density of twins in fully oxidized materials depends on the distances between Y2BaCuO5 inclusions, larger twin densities are related to shorter distances between inclusions. The influence of phase composition of the initial powder mixtures on the distances between Y2BaCuO5 inclusions have been characterized and discussed.
Frequency-dependent demagnetisation rate of a shielded HTS tape stack
Authors: Tomkow Lukasz , Climente-Alarcon Vicente , Mineev Nikolay , Smara Anis , Glowacki Bartek A.
Published: June 2020

This work presents results of investigation of crossed-field demagnetization in 2G high temperature superconducting stacks at temperatures in the range of 77 - 20 K and in a variable frequency, corresponding to the particular rotor application.

We propose a method to reduce the demagnetization rate for a given stack configuration necessary for the superconducting rotor operating at a cryogenic temperature. This technique involves 3-D wrapping the stack of tapes with perpendicular layers of similar superconducting properties.

Previous ‘proof of concept’ studies documented some improvements in flux demagnetisation reduction for basic configuration. In the present study a more advanced approach based on magnetic flux shielding is adopted. The presented results provide an important contribution to development for design solutions that aim to increase the operational time before remagnetisation of the stacks would be required.
Impact of 440 GeV Proton beams on Superconductors in a Cryogenic Environment
Authors: Will A. , Bernhard A. , Bonura M. , Bordini B. , Mentink M. , Mueller A.-S. , Oslandsbotn A. , Schmidt R. , Schubert J. , Senatore C. , Siemko A. , Verweij A. , Wollmann D.
Published: June 2020

The superconducting magnets used in high energy particle accelerators such as CERN’s LHC can be impacted by the circulating beam in case of specific failures. This leads to interaction of the beam particles with the magnet components, like the superconducting coils, through direct beam impact or via secondary particle showers. The interaction causes energy deposition in the timescale of microseconds and induces large thermal gradients within the superconductors, which are in the order of 100 K/mm. To investigate the effect on the superconductors, an experiment at CERN’s HiRadMat facility was designed and executed, exposing short samples of Nb-Ti and Nb3Sn strands in a cryogenic environment to microsecond 440 GeV proton beams. The irradiated samples were extracted and analyzed for their critical transport current I
c. This paper describes the results and analysis of the measurements of I
c as well as thermo-mechanical simulations of the Nb3Sn strands to evaluate the degradation of I
c as a function of the mechanical strain present during and after the beam impact.
Transport current distribution in soldered joint of BSCCO and REBCO tapes
Authors: Chikumoto Noriko , Yamaguchi Satarou , Shyshkin Oleg
Published: June 2020

Transport current density distribution at the solder joints of BSCCO tapes and GdBCO tapes are examined by means of scanning 3-dimensional (3D) Hall sensor. After measuring the three components,
B
x, B
y
and
B
z
, of self field distribution near the tape induced by the transport current, the current density distribution was calculated by solving the inverse problem through matrix method implemented in the code in MATLAB environment. By using this technique, we successfully obtained the profiles for perpendicular component
J
z
of transport current that is passing through the joint area.
Long term operation of the superconducting triplet quadrupoles with cryocoolers
Authors: Kusaka K
Published: June 2020

Superconducting triplet quadrupoles (STQs) with cryocoolers characterize the BigRIPS in-flight separator and radioactive isotope (RI) beam delivery lines in the RIKEN RIBF (Radioactive Isotope Beam Factory) project. The STQ magnet is a large-aperture superferric quadrupole triplet cooled by liquid helium bath cooling method in a single cryostat. The STQ cryostat is designed to be operated continuously with a Gifford-McMahon (GM)/Joule-Thomson (JT) cryocooler and a GM cryocooler. We operate 22 STQ systems for more than twelve years without warm-up the magnets. We report operational experiences, such as degradation of cooling capacity and failures of compressors, in the long-term operation of the STQ systems. Replacement of ageing cryocooler unit is discussed to improve the cooling capacity.
Mechanical design of a nested 4-layer Canted Cosine Theta (CCT) dipole
Authors: Ortwein Rafal , Blocki Jacek , Kirby Glyn , van Nugteren Jeroen
Published: June 2020

Nested CCT dipoles could be used in particle accelerators and proton therapy machines to bend a beam of charged particles in any direction. In the present study, a mechanical design of a 4 layer nested CCT dipole is evaluated with Finite Element Method (FEM). A full parametric 3D model of a 2.5 Tm 4-layer CCT dipole has been developed using the APDL scripting in the ANSYS software. The, so called, bottom up approach with direct generation of nodes and elements has been utilized, optimizing for the speed of the model generation as the time consuming meshing was bypassed. The properties of the Nb-Ti strands with the surrounding CTD-101K epoxy were obtained with a dedicated homogenization model. Resulting orthotropic properties were fully accounted for in the simulation. The shear stresses in the bonding composite layer: Kapton+S2-glass+CTD-101K were computed. With the results above the limit of 10 MPa, the necessity to provide additional rigidity against the torque was confirmed – castellated design. The shear stresses were mostly caused by thermal effects, and only ~25 % was caused by the Lorentz forces. The influence of the boundary conditions was analysed, leading to their optimal choice limiting the deformation due to Lorentz forces to 91 μm.
Feasibility of ultra-compact HTS CrossConductor based Power Transmission Cables
Authors: Kottonau Dustin , Wolf Michael , Fietz Walter , Stammen Jörg , Hirsch Holger
Published: June 2020

HTS CrossConductor is a compact stacked-tape REBCO conductor of high current density. In this contribution, a non-concentric three-phase cable design based on HTS CroCos is presented, which offers the possibility to reduce the cable diameter significantly. One of the important aspects of HTS-AC power cables are the AC-losses, which are investigated both theoretically and experimentally. For the measurement of the dissipated power loss in both single-phase and three-phase conductor arrangements, a calorimetric method is used. The results indicate that it is possible to reduce the outer cable diameter compared to concentric cables designs by a factor of two. When the losses of such a cable with HTS CroCo design shall not exceed 2 W/m for all three-phases, the maximum ampacity results in a current of 600 A(rms) per phase. Depending of the target there are many potential applications for such an ultra-compact HTS CroCo-based power transmission cable design.
Effect of a PTFE film on bubble triggered DC breakdown characteristics in liquid nitrogen
Authors: Gao Lei , Xiang Bin , Junaid Muhammad , Liu Zhiyuan , Geng Yingsan , Wang Jianhua
Published: June 2020

In the resistive type DC superconducting fault limiter (R-SFCL), the insulation strength will be decreased seriously when the R-SFCL quenched. Insulation barriers are used inside of the R-SFCL to enhance the electrical breakdown strength of the SFCLs. The objective of this paper is to study the barrier effect on the DC breakdown characteristics of the liquid nitrogen (LN2)/insulation barrier composite system with and without bubbles. In the experiment, the DC breakdown voltage of a pair of rod-plane electrodes with an insulation barrier was measured in the presence of thermal bubbles. The results show that for both the positive and negative polarities, the breakdown voltage of the LN2/insulation barrier composite system is higher than that without the barrier. In the presence of the bubbles, the breakdown voltage of the LWinsulation barrier composite system is about 1.5 times higher than without the barrier. Furthermore, the breakdown voltage of the LN2/insulation barrier composite system with 0.04 mm PTFE is higher than with 0.1 mm PTFE. The results suggested that the barrier effect could not only improve the insulation strength of the normal state but also the quench state of the R-SFCLs.
Quench Protection for Superconducting Insertion Magnets
Authors: Green Michael A.
Published: June 2020

Quench protection for Nb-Ni insertion magnets (wigglers and undulators) has not been a problem. The reasons are; the quench is relatively easy to detect, the stored energy is low, the quench propagates rapidly, quench heaters work because the coil thermal diffusivity at 4.5 K is high, and quench protection resistors will work. Superconducting insertion magnets require very high current densities in the magnet coil in order to be competitive with permanent magnet insertion magnets. The need for high coil current densities makes superconductors like Nb3Sn and ReBCO HTS tapes attractive. The higher temperature superconductors have much lower quench propagation velocities, and the high-current-density versions of these materials often have much less copper in them than Nb-Ti. Since the quench temperature for these superconductors is two to ten times higher than Nb-Ti, the coil thermal diffusivity is much lower. This paper presents a number of quench protection options for insertion magnets made from materials other than Nb-Ti.
Novel HTS coil protection method using secondary windings as a quench heater
Authors: Onodera Y , Mito T , Takahata K , Hirano N
Published: June 2020

In NIFS, research and development of HTS magnets have been begun aiming at the application to a next experimental device of Large Helical Device which is a heliotron-type fusion plasma experimental device. The next experimental device needs large coil current density such as 80 A/mm2, therefore it is important to develop a coil protection method. In this study, we have proposed a novel coil protection technology of HTS magnets using secondary windings. By embedding secondary windings which are electrically isolated in a part of the conductor and using the secondary windings as a quench heater, the occurrence of normal conduction is quickly diffused, then prevented local temperature rise in the HTS coil. We applied this method to the conductor and coil under development, and analysed the thermal behaviour of the secondary windings. As a result, we found that the temperature rise of the entire coil can be suppressed and the hotspot region can be diffused. This shows the applicability of coil protection by using the secondary windings, therefore optimal coil protection is possible by changing the ratio of magnetic stored energy between internal consumption and external recovery depending on the value of external resistance.
Screening Current-Induced Field and Field Drift Study in HTS coils using T-A homogenous model
Authors: Berrospe-Juarez Edgar , Trillaud Frederic , Zermeño Víctor M R , Grilli Francesco
Published: June 2020

The emergence of second generation (2G) high-temperature superconductor (HTS) tapes has favored the development of HTS magnets for their applications in areas such as NMR, MRI and high field magnets. The screening current-induced field and the field drift are two major problems hindering the use of HTS tapes in the mentioned areas. Both problems are caused by the screening current, then it is necessary to have a modeling strategy capable to estimate such phenomena. Thus far, the H formulation has been a widely used approach to model medium-size systems (hundreds of tapes). However, its application to large-scale systems is still impaired by excessive computation times and memory requirements. Homogenization and multi-scaling strategies have been successfully implemented to increase the computational efficiency. In this contribution, we show that using the homogenization technique with the recently developed T-A formulation allows reducing the computation time and the amount of memory up to the point that realtime simulations of slow ramping cycles of large-scale systems are possible. At the same time, the T-A homogeneous model provides enough resolution to investigate the screening current using numerical simulations.
Measurement of splice resistance and normal zone propagation velocity in REBCO tapes for the Superconducting Link of HL-LHC
Authors: Matras M. , Fleiter J. , Ballarino A.
Published: June 2020

The Superconducting Link (SC-Link) being developed at CERN in the context of the LHC High-Luminosity upgrade (HL-LHC) will supply the current to superconducting magnets of the HL-LHC Inner Triplets and Matching Sections. The SC-Link consists of MgB2 highcurrent cables, and it includes high temperature superconducting REBCO cables making the electrical transition between the MgB2 and the current leads. Electrical protection of superconducting devices made of REBCO against unexpected quenches is challenging especially when operation is at high current density. Adequate electrical protection of REBCO cables is crucial to insure good performance of the circuit over the lifetime of the machine; protection relies on the detailed knowledge of the quench propagation velocity. In this paper we reviewed the electromagnetic properties of REBCO tapes procured for prototype work. We measured the splice resistance (Rs
) of the REBCO conductors and found a significant variation among the different batches of conductor. The normal zone propagation velocity (NZPV) was reported to be affected by the interfacial resistance which is governing the splice resistance: increasing the interfacial resistance enhances the NZPV. In order to determinate the influence of the internal resistance on the quench behaviour of the tapes, we investigated the normal zone propagation velocity of the epoxy-impregnated tapes at 77 K in self-field and 4.2 K in field up to 7 T in the FRESCA test station. We found that despite the Rs
variation observed (up to factor 4), the tapes show similar NZPV at both temperatures. In addition we observed a significant field dependence of the NZPV of the tapes at 4.2 K. The results are compared to numerical simulation and discussed.
Electromagnetic Performance of 10-MW HTS Double-Stator Flux Modulation Generators Considering Distributed/Concentrated Armature Winding
Authors: Cheng Yi , Qu Ronghai , Gao Yuting , Zhang Yuanzhi , Wang Qian
Published: June 2020

For HTS conventional synchronous generator, the superconducting (SC) field windings or armature windings are rotating, which could complicate their industrial feasibility for the off-shore wind generation. In order to overcome this drawback, a kind of HTS double-stator flux modulation generator (HTS-DSFMG) with stationary seal is proposed. Meanwhile, the electromagnetic performances of 10-MW HTS double-stator flux modulation generators with two different armature winding structure, i.e., distributed and concentrated armature windings are compared in this paper. In detail, the magnetomotive force (MMF) harmonic and the saturation effect of each armature winding structure have been studied. The objective is to intensive study the advantages and disadvantages of HTS-DSFMG with different armature windings, and to find the suitable configuration of the armature winding for large scale HTS double-stator flux modulation generators.
Superconducting Propulsion System with LH2 Cooling for All-Electric Aircraft
Authors: Dezhin D , Dezhina I , Ilyasov R
Published: June 2020

The article discusses the advantages of using liquid hydrogen to cool superconducting electric machines for an all-electric aircraft. Calculation schemes and basic parameters of superconducting electric machines with liquid hydrogen cooling are presented. It is shown that liquid hydrogen is practically a non-alternative type of fuel for future electric aircraft because of its high energy intensity and environmental cleanliness.
Principal analysis of hybrid power systems with HTS electrical machines
Authors: Kovalev K L , Ivanov N S , Ilyasov R I , Penkin V T , Zechikhin B S
Published: June 2020

The hybrid power systems (HPS) for transport application are currently under consideration. It causes with ecological and fuel efficiency aspects. The successful solving the problems of enhancing the specific output power parameter, fuel efficiency and diminishing weight of such systems focus on a use the cryogenic cooling and cryogenic fuel as a source of on-board energy. The article is devoted to the analysis and comparison of HPS of different design. The comparison is provided for HPS with different fuel (diesel oil, kerosene, petroleum, liquid natural gas, and liquid hydrogen). The analysis of application in HPS of different types of conventional and HTS electrical machines illustrates the advantage of the latter. The prospective of application of cryogenic power electronics is considered like advanced for HPS. Besides the article provides specific parameters of the HPS with HTS generator, motor, cryogenic electronics and HTS power cable at different cooling
Temperature and strain rate effect on flow stress of al2075/bottom ash composite
Authors: Supriyanto F D , Seputro H , Rinaldi H , Akbar H I
Published: June 2020

This study focused to determine the flow stress of Al 2075 composites with bottom ash reinforcement. Metal forming process is very important in an industry, materials can be plastic deformed requires several parameters of the forming process, such as the material flow stress. Temperature and strain rate affect the flow stress material. In this paper the tensile test carried out at 350°C, 400°C and 450°C and the strain rate varied 1 mm.s−1, 10−1 mm.s−1 and 10−2 mm.s−1. Tensile test showed that the highest flow stress is obtained at 350°C and a draw rate of 1 mm.s−1, the higher the temperature will decrease the flow stress, while the faster the strain rate increased the material flow stress.
The failure farmers in panti district to control tungro disease which endemic in 2014-2019
Authors: Wahyuni W S , Sayekti J B A
Published: June 2020

Tungro disease in rice plants is transmitted by green leafhoppers (Nephotettix virescens) in a semi-persistent manner. This disease has spread in Panti District from 2014-2019, especially at the beginning and the end of rainy season. This paper wanted to explain why farmers in Panti failed to overcome the endemic tungro disease. The study was conducted by questionnaire and direct observation in the field. Actually farmers in this district had received integrated pest control (IPM) information, but they have not implemented properly. In 2018-2019, based on respondents at Kemuning Lor, Glagahwero and Pakis, most farmers planted rice along the year because of a good irrigation system. Although the plant was infected, the rice yield was still ± 40-60%, except for some field in Pakis (≤ 30%). The farmers in Pakis let their plants infected without hope, but they still grew rice continuously. A few farmers in Kemuning Lor controlled the vector mechanically by yellow light trap, other farmers used pesticides. The failure farmers to control tungro disease caused by several factors, i.e (1) continuous rice planting throughout the year, (2) the varieties grown were mostly remained, it was IR 64 which has good taste, and the selling price was more expensive than other varieties, (3) improper pesticide selection. Although they grew rice almost in the same time, but because of they planted continuously a year, the tungro disease still present there. Therefore, to reduce this damage, further education is needed on IPM and farmers' awareness is needed to work together to implement IPM properly.
Student’s perspective about electrical voltage of fruit cells through STEM
Authors: Setiawan A M , Munzil  , Marsuki M F , Nugraheni D , Hanifiyah F , Husnayaini N
Published: June 2020

The use of batteries in electronic tools can cause environmental pollution. This problem can be solved by using natural ingredients that can replace conventional batteries as a source of electrical voltage. This topic is suitable for students to learn in class by reviewing aspects in the fields of Science, Technology, Engineering, and Mathematics (STEM). For STEM’s activities, we used Yuenyong’s Science-Technology-Society (STS) approach, and for data analysis, we used mixed methods, where quantitative methods to classify the data and qualitative methods to analyze student perspective. In this study, students are given lemons, limes, potatoes, apples, tomatoes, and cucumbers as fruit cells. Then all fruits are connected by coins, nails, cables, multimeters, and LED lamps. The results obtained by students is conventional batteries cells can be replaced by fruit cells. All fruit cells that we used like cucumber, apples, tomatoes, limes, lemons, and potatoes are capable of producing electrical voltage. Cucumbers and tomatoes produce the higher electrical voltage (5,0 volts & 3.0 volts) but have a dim LED’s light, while potatoes, lemons, limes, and apples produce the lower electrical voltage (1.35 volts, 2.0 volts, 2.2 volts, and 3.4 volts) but have bright LED lights.
Development of learning media using VBA excel in physical learning in senior high school
Authors: Safitri A D , Lesmono A D , Maryani  , Wardoyo A A
Published: June 2020

This study aims to examine the practicality and effectiveness of instructional media. This research uses research and development research. The development procedure in this study uses 4D which has four stages namely define, design, develop, and disseminate. This study examines the disseminate stage of validating testing. The results of the development stage to state that they are valid, practical and effective. The subject of the dissemination stage of this study were students of class XI MIA-1, XI MIA-2, and XI MIA-4 at SMA Umbulsari. Data collection is done through pre-test and post-test and student questionnaire responses. The results of validating testing at the disseminate stage to measure the practicality of learning media carried out by XI MIA-1, XI MIA-2, and XI MIA-4 respectively scored 81.32%, 80.20%, and 81.46%, obtaining criteria practical and get effective enough criteria for the effectiveness of learning media using VBA Excel with a score of 40.05% at XI MIA 1, 36.21% at XI MIA 2 and 39.23% at XI MIA 4 based on the N-Gain test criteria.
The analysis of the application of learning materials based on project-based learning to improve the elementary school students’ creative thinking skills in solving contextual division problems
Authors: Shalihah N H , Dafik  , Prastiti T D
Published: June 2020

This study aims to investigate the analysis learning materials implementation based on project-based learning to improve the elementary school students’ creative thinking skills in solving contextual division problems. This type of research is using a mixed research, which is a combination of quantitative and qualitative methods. The research respondents consist of two classes, namely a control class as many as 19 students and an experimental class as many as 20 students. The results shows after the implementation using the application learning materials base on project-based learning, it was found that the presentation of students' creative thinking skills for the control class are 77,19% for fluency, 70,18% for flexibility, and 56,14% for novelty. While the experimental class are 82,5% for fluency, 91,67% for flexibility, and 67,5% for novelty. Then the score of the indepent sample t-test from post-test shows that there is a significant difference between the control class and the experimental class with the sig (2-tailed) value is 0.000 (p = <0,05). It can be concluded that the application learning materials base on project-based learning can improve students' creative thinking skills in solving contextual division problems.
The matthayom and senior high school student’s metacognition profile on solving pisa test shape and space content based on van hiele level
Authors: Firmansyah F F , Aribowo B E , Damayanti R , Sari M P , Sunardi  , Yudianto E
Published: June 2020

Profile of the students’ metacognition observed in this research was an activity that involved the abilities and metacognition processes of the students at each level of van Hiele thinking, including knowledge of metacognition and metacognition settings in solving geometrical problems in shape and space content. This type of research was descriptive with qualitative approach. Descriptive research was used in this research because it described or explained the variables studied, namely the level of van Hiele and Metacognition in schools in Indonesia and Thailand. The data collection methods used were van Hiele, PISA and interview tests. The results of the data analysis found that the students of visual level in Indonesia and Thailand in the planning stage were able to think about what to do, but in the monitoring stage, the students asked themselves questions about the purpose of the problems. However, in the evaluation stage they still doubt of what they decided, the students of analysis level in Indonesia and Thailand in the planning, monitoring and evaluation stages were quite sure of what they have thought.
The analysis of the implementation of multi techniques based learning media in improving the elementary school students’ higher order thinking skill in solving exponential problem
Authors: Masruroh L , Dafik  , Suprapti
Published: June 2020

This study aims to investigate the analysis of the implementation of multi techniques based learning media in improving the elementary school students’ higher order thinking skill in solving exponential problem. This is caused by the lesson plans cannot motivate students to improve higher order thinking skills. The method used in this study is a mixed method which is a combination of quantitative and qualitative methods. The research subjects were the fifth grade students of elementary school consisting of 25 students of experimental class and 24 students of the control class. The instruments of this research are an interview, a questionnaire, observation, and documentation. Quantitative method is applied to analyze the difference of student achievement result among two classes, while the qualitative method is applied to analyze the students' higher order thinking skills. The results show that there are significant differences between the two classes that applied multi techniques based learning and conventional learning. The statistical result indicates that the (2-tailed) significance of the independent sample t-test in the pre-test was 0.000 or α ≤ 0.05. It implies that the implementation of multi techniques media affects the students' higher order thinking skill in solving exponential problem.
Optimization of Management System of Independent Enrollment Based on Quantum Evolutionary Algorithm
Authors: Wang Yanqin
Published: June 2020

The independent enrollment of colleges and universities is a heavy task for colleges and universities. With the development of information technology, when colleges and universities conduct independent enrollment, many data hit in a flash. The statistical analysis of data brings difficulties to the general independent enrollment management system. This paper relies on quantum evolution algorithm to optimize the independent enrollment system, aiming to sort out and optimize the enrollment, the work flow of student management provides real-time data query and analysis services for relevant functional departments and individuals, realizes the linkage between the enrollment system and other systems of the school, improves the efficiency and management level of enrollment management, effectively improves the efficiency of independent enrollment, opens data interface for the access of other systems, and provides new work, student information management and financial management in the later stage work provides convenient and efficient information support.
Multi-attribute Probability Caching Algorithm in Named Data Network
Authors: Zhang Li , Zhang Qiang
Published: June 2020

Since entering the new century, Internet technology has developed rapidly and has become an important infrastructure in today’s society. In recent years, with the popularization of optical fiber applications, the network bandwidth has been greatly improved, and the growth rate of network traffic has also shown explosive growth. The traditional TCP/IP network has exposed many serious problems in the face of increasing traffic. In particular, the issues of scalability, reliability, security, flexibility and mobility are more prominent. In order to solve the shortcomings of the existing Internet architecture, the current domestic and international schemes mainly include "improvement" and "revolution". Improvement is the gradual improvement of the deficiencies of the existing Internet system. However, this method cannot essentially solve these deficiencies, and it is difficult to meet the needs of future network development. The revolution is to redesign the information-centric network as the Internet system structure, completely changing the existing Internet system in terms of scalability, security and mobility, in order to adapt to the needs of future social development. Named-Data Networking (NDN) in many information-centric network architectures is a network architecture with excellent research and development. This article focuses on the research of NDN network caching technology. In terms of caching decisions, a multi-attribute probabilistic caching algorithm is proposed, which can effectively reduce the cache of redundant data in routing nodes in NDN networks and improve the utilization of routing node cache space, reduce network delay, increase the cache hit rate of routing nodes, and improve the overall performance of the NDN network.
Research on control algorithm of the upper limb rehabilitation robot based on PI hysteresis compensation
Authors: Zhiming Wang , Wangwei Ye , Sijia Gong , Qi Hua
Published: June 2020

The upper limb rehabilitation robot is used to assist patients with upper limb hemiplegia for rehabilitation training. During the passive rehabilitation training of the patient, the trajectory of the rehabilitation training must be as smooth as possible, so that the patient will not feel discomfort when pulling the affected limb. The passive control algorithm of the existing upper limb rehabilitation robot is not ideal for the lag processing of the system. This paper designs a passive control algorithm based on PI hysteresis compensation. The hysteresis effect of the system can be greatly reduced by introducing the hysteresis compensation term uc
. Experimental results show that the algorithm can effectively eliminate the hysteresis effect of the system.
An improved salp optimization algorithm inspired by quantum computing
Authors: Tian Fanghao , Wei Hongkui , Li Xu , Lv Meibo , Wang Pei
Published: June 2020

Salp Swarm Algorithm (SSA) is a novel optimization algorithm which is widely used in engineering problems. An improved SSA inspired by quantum computing is proposed in this paper. The principles of quantum computing, such as qubits and quantum states, are introduced into the original SSA in order to overcome the defect of trapping into local optimum easily. Instead of updating the salp position directly, the quantum angle related to the quantum state is updated to increase the diversity of states. Two multidimensional benchmark functions are used to verify the proposed improved SSA, the result shows that the introduction of quantum computing can successfully prevent the SSA from falling into the local optimum and increase the accuracy.