bluuebunny/crossref_metadata_2025 huggingface dataset:
Route to form skyrmions in soft magnetic films
Authors: Navas D. , Verba R. V. , Hierro-Rodriguez A. , Bunyaev S. A. , Zhou X. , Adeyeye A. O. , Dobrovolskiy O. V. , Ivanov B. A. , Guslienko K. Y. , Kakazei G. N.
Published: August 2019

Magnetic skyrmions which are topologically nontrivial magnetization configurations have attracted much attention recently due to their potential applications in information recording and signal processing. Conventionally, magnetic skyrmions are stabilized by chiral bulk or interfacial Dzyaloshinskii-Moriya interaction (DMI) in noncentrosymmetric B20 bulk crystals (at low temperatures) or ultrathin magnetic films with out-of-plane magnetic anisotropy (at room temperature), respectively. The skyrmion stability in the ultrathin films relies on a delicate balance of their material parameters that are hard to control experimentally. Here, we propose an alternate approach to stabilize a skyrmion in ferromagnetic media by modifying its surroundings in order to create strong dipolar fields of the radial symmetry. We demonstrate that artificial magnetic skyrmions can be stabilized even in a simple media such as a continuous soft ferromagnetic film, provided that it is coupled to a hard magnetic antidot matrix by exchange and dipolar interactions, without any DMI. Néel skyrmions, either isolated or arranged in a 2D array with a high packing density, can be stabilized using antidot as small as 40 nm in diameter for soft magnetic films made of Permalloy. When the antidot diameter is increased, the skyrmion configuration transforms into a curled one, becoming an intermediate between the Néel and Bloch skyrmions. In addition to skyrmions, the considered nanostructure supports the formation of nontopological magnetic solitons that may be regarded as skyrmions with a reversed core.
Radiation enhanced oxidation of proton-irradiated copper thin-films: Towards a new concept of ultra-high radiation dosimetry
Authors: Gorine Georgi , Pezzullo Giuseppe , Bouvet Didier , Ravotti Federico , Sallese Jean-Michel
Published: August 2019

The effects of extreme radiation levels on the electrical resistivity of metal thin films made of copper were studied by means of electrical measurements and post irradiation imaging. Different 3x3 mm2 chips were produced by depositing 500 nm of meander shaped copper on top of a silicon substrate. A subset of samples was also passivated by sputtering 300 nm of SiO2. During irradiation with 23 GeV protons up to 1.2 x 1017 p/cm2 at the CERN IRRAD Proton Facility, only not-passivated copper samples have shown an increase of resistivity proportional to the particle fluence, indicating that the dominant factor of the resistivity increase is not directly an accumulation of displacement damage, but the radiation enhanced oxidation of the copper film exposed to air. Post-irradiation imaging of the chips cross sections has confirmed the presence of a grown copper oxide film on the surface as well as oxide wells that extended within the bulk following the grain boundaries. This permanent increase of resistance due to radiation enhanced oxidation, can be used for monitoring high energy particles fluence up to levels currently not reachable by standard silicon technology.
Asymmetric viscothermal acoustic propagation and implication on flow measurement for SOFC
Authors: Zhou Dan , Sun Ke , Chen Xixiang , Zheng Weimin , Chen Yong
Published: August 2019

In the applications of heating generation based on the solid oxide fuel cells (SOFC) technology, a high-accuracy performance of flow measurement is of great importance. Due to the advantage of non-invasive no-moving-parts construction and bi-direction measurement, ultrasonic flow meter, where viscothermal dissipation and asymmetric acoustic modes cannot be overlooked, may be a promising method in the SOFC-based applications. The present paper mathematically formulates asymmetric linear disturbance dynamics in terms of velocity and temperature disturbances based on the conservations of mass, momentum and energy. An iterative calculation procedure, which is similar to Galerkin method, is presented. Numerical analysis of asymmetric acoustic features (phase velocity and attenuation coefficient) are comprehensively given under the effects of viscothermal dissipation and shear flow convection. In the end, flow measurement performance of asymmetric acoustic modes is literally discussed. Numerical study shows that viscothermal dissipation affects the cut-on frequency of acoustic modes and couples nonlinearly with shear convection when the flow Mach number is large. These parameters impose significant influences on measurement performance. Each acoustic mode has inherent measurement derivation which can be theoretically used to compensate the acoustic flow measurement error. Apparent prediction error may occur if the viscothermal dissipation is taken out of consideration.
Numerical analysis of auto-catalytic glycolysis model
Authors: Ahmed Nauman , S. S. Tahira , Imran M. , Rafiq M. , Rehman M. A. , Younis M.
Published: August 2019

The main purpose of this paper is to investigate the solution of general reaction–diffusion glycolysis system numerically. Glycolysis model demonstrates the positive solution as the unknown variables show concentration of chemical substances. Three numerical methods are used to solve glycolysis model. Two methods are well-known finite difference (FD) schemes and one is proposed FD scheme. The proposed scheme is explicit in nature. The main feature of the proposed FD scheme is to preserve the property of positivity retained by the glycolysis model. Results are compared with forward Euler explicit scheme and Crank Nicolson implicit scheme. All the attributes are verified by simulations.
Formation and transformation of Al–Fe phases after friction stir processing
Authors: Ding Zhimin , Li Zhiwen , Zhao Yadong , Chen Ying
Published: August 2019

Based on the preparation of magnesium (AZ31B) – aluminium (1060) composite materials by friction stir processing, a study of the formation and transformation of Al–Fe phases in the aluminium solid solution near the Al–Mg interface was performed by transmission electron microscopy. The results show that there are many Al6Fe particles with the size span range of 100–300 nm in the aluminium solid solution, and the morphology of Al6Fe centre phase encapsulated by Al3Fe thin-layer phase was observed. Meanwhile, the interface types of Al–Al3Fe and Al3Fe–Al6Fe are both coherent interfaces, and there are crystallographic orientation relationships between them, namely: [Formula: see text] [Formula: see text]

The crystallographic orientation relationships have not been reported yet.
Review of cold spraying and its use for metallic glass coatings
Authors: Su Juan , Kang Jia-jie , Yue Wen , Ma Guo-zheng , Fu Zhi-qiang , Zhu Li-na , She Ding-shun , Wang Hai-dou , Wang Cheng-biao
Published: August 2019

Cold spraying (CS), a solid-state spraying technology, is expected to become an appropriate supplementary for traditional spraying methods owing to its plenty of merits such as high deposition efficiency, low temperature and little influence on the particles/substrate. The most reported researches are bulk alloys fabricated by CS. However, the systematic introduction and cold-sprayed metallic glass coatings have not been summarised. Therefore, in this paper, the international research status of CS including equipment structure, spraying process and parameters, advantages and disadvantages, deposit features and bonding mechanism were introduced. By using this technology, the successful researches about Fe-, Al-, Ni-, Cu- and Zr- based amorphous alloy coatings are reported. To overcome the limitations, further development and solutions were proposed.
Magnetooptical response of permalloy multilayer structures on different substrate in the IR–VIS–UV spectral range
Authors: Patra Rajkumar , Mattheis Roland , Stöcker Hartmut , Monecke Manuel , Salvan Georgeta , Schäfer Rudolf , Schmidt Oliver G , Schmidt Heidemarie
Published: August 2019

The magnetooptical (MO) response of Ru/Py/Ta thin film stacks with 4, 8, and 17 nm thick Ni81Fe19 permalloy (Py) films on a SiO2/Si and a ZnO substrate was measured by vector magnetooptical generalized ellipsometry. The MO response from VMOGE was modelled using a 4  ×  4 Mueller matrix algorithm. The wavelength-dependent, substrate-independent and thickness-independent complex MO coupling constant (
Q
) of Py in the Ru/Py/Ta thin film stacks was extracted by fitting Mueller matrix difference spectra in the spectral range from 300 nm to 1000 nm. Although the composition-dependent saturation magnetization of Ni
x
Fe1−x
alloys (x  =  0.0…1.0), e.g. of Ni81Fe19, is predictable from the two saturation magnetization end points, the MO coupling constant of Ni
x
Fe1−x
is not predictable from the two
Q
end points. However, in a small alloy range (0.0  <  x  <  0.2 and 0.8  <  x  <  1.0) the composition-dependent
Q
of Ni
x
Fe1−x
can be interpolated from a sufficiently high number of analyzed Ni
x
Fe1−x
alloys. The available complex MO coupling constants of six different Ni
x
Fe1−x
(x  =  1.0 to 0.0) alloys were used to interpolate MO response of binary Ni
x
Fe1−x
alloys in the range from x  =  0.0 to x  =  1.0.
In situ electrochemical oxidation of electrodeposited Ni-based nanostructure promotes alkaline hydrogen production
Authors: Pang Yajun , Yu Yong , Chen Hao , Xu Guangqing , Miao Linqing , Liu Ximeng , Pan Zhenghui , Kou Zongkui , Wu Yucheng , Wang John
Published: August 2019

Highly active and stable electrocatalysts based on non-precious metals for hydrogen evolution reaction (HER) in alkaline solution are urgently required for enabling mass production of clean hydrogen in industry. Herein, core–shell NiOOH/Ni nanoarchitectures supported on the conductive carbon cloth have been successfully prepared by a facile electrodeposition process of Ni, and a subsequent in situ electrochemical oxidation. When explored as an alkaline HER electrocatalyst, the as-synthesized NiOOH/Ni nanoarchitecture requires only a low overpotential of ∼111 mV to attain a current density of −10 mA cm−2, demonstrating its strong catalytic capability of hydrogeneration. The excellent HER activity could well be attributed to the decreasing charge transfer resistance and competitive electrochemical active area of the amorphous NiOOH, compared with inactive Ni substrate. The feasible methodology established in this study can be easily expanded to obtain a series of nano-sized metal oxyhydroxide materials for various energy conversion and storage applications, where Ni-based nanomaterials are among the highly active ones.
Tunable topological valley transport in two-dimensional photonic crystals
Authors: Wang Yujing , Zhang Weixuan , Zhang Xiangdong
Published: August 2019

Recently, exploring the valley degree of freedom in photonic crystals has attracted considerable attentions since it opens up the possibility of extending valleytronics to optics. However, the fixed structural parameters limit the practical applications of valley photonic crystals. How to design steerable valley photonic structures becomes an important research topic. In this work, we design a tunable valley photonic crystal using an array of regular triangular metal rods embedded in liquid crystals. Electrically controlled valley-selective excitation, valley-locked beam splitting behavior and valley-projected edge transportation have been numerically demonstrated. Using these novel effects, a switchable valley filter device has also been designed. Our proposed valley-based photonic devices are beneficial for the development of robust wave manipulation.
Magnetization dynamics and related phenomena in semiconductors with ferromagnetism
Authors: Chen Lin , Zhao Jianhua , Weiss Dieter , Back Christian H. , Matsukura Fumihiro , Ohno Hideo
Published: August 2019

We review ferromagnetic resonance (FMR) and related phenomena in the ferromagnetic semiconductor (Ga,Mn)As and single crystalline Fe/GaAs (001) hybrid structures. In both systems, spin-orbit interaction is the key ingredient for various intriguing phenomena.
High temperature magnetic semiconductors: narrow band gaps and two-dimensional systems
Authors: Gu Bo
Published: August 2019

Magnetic semiconductors have been demonstrated to work at low temperatures, but not yet at room temperature for spin electronic applications. In contrast to the p-type diluted magnetic semiconductors, n-type diluted magnetic semiconductors are few. Using a combined method of the density function theory and quantum Monte Carlo simulation, we briefly discuss the recent progress to obtain diluted magnetic semiconductors with both p- and n-type carriers by choosing host semiconductors with a narrow band gap. In addition, the recent progress on two-dimensional intrinsic magnetic semiconductors with possible room temperature ferromangetism and quantum anomalous Hall effect are also discussed.
Generalised ‘Arcsine’ laws for run-and-tumble particle in one dimension
Authors: Singh Prashant , Kundu Anupam
Published: August 2019

The ‘Arcsine’ laws of Brownian particles in one dimension describe distributions of three quantities: the time t

m
to reach maximum position, the time t

r
spent on the positive side and the time of the last visit to the origin. Interestingly, the cumulative distribution of all three quantities are the same and given by Arcsine function. In this paper, we study distribution of these three times and in the context of single run-and-tumble particle in one dimension, which is a simple non-Markovian process. We compute exact distributions of these three quantities for arbitrary time and find that all three distributions have a delta function part and a non-delta function part. Interestingly, we find that the distributions of t

m
and t

r
are identical (reminiscent of the Brownian particle case) when the initial velocities of the particle are chosen with equal probability. On the other hand, for , only the non-delta function part is the same as the other two. In addition, we find explicit expressions of the joint distributions of the maximum displacement and the time at which this maxima occurs. We verify all our analytical results through numerical simulations.
Adsorption of toluene and xylene from aqueous solution on SBA-15 from rice husk
Authors: Prestianggi Y , Maylisa N , N Subagyono RR D J , Sitorus S , Daniel
Published: August 2019

Synthesis of Santa Barbara Amorphous-15 (SBA-15) from rice husk ash (Oryza Sativa L.) as toluene and xylene adsorbents has been performed. SBA-15 was synthesised by the modified surfactant template method. SBA-15 from rice husk ash has a surface area of 680 m2/g, a pore diameter of 1.49 nm and a pore volume of 12.5 cm3/g. SAXS pattern of the SBA-15 showed the presence of three distinctive peaks of SBA-15 at 0.99°, 1.54° and 1.74° 2 theta with miller indices [100], [110] and [200]. SEM pictures showed that SBA-15 from rice husk ash has an irregular shape and the particles are in aggregate form. The maximum adsorption capacities of SBA-15 from rice husk ash to toluene and xylene based on the Langmuir isotherm were 175.44 mg/g and 142.86 mg/g, respectively with RL (equilibrium parameter) value within the range 0-1.
Antioxidant and anticancer activity of Eleutherine bulbosa (Mill.) Urb on leukemia cells L1210
Authors: Lestari D , Kartika R , Marliana E
Published: August 2019

Antioxidant and anticancer activity test on Leukemia cells L1210 were carried out on four fractions (ethanol extract, n-hexane, chloroform, and water fraction) of Eleutherine bulbosa [Mill.] Urb. The purpose of this research is to obtain IC50 antioxidant and anticancer activity of the active fraction of Eleutherine. bulbosa [Mill.] Urb on Leukemia cells L1210. The research method includes antioxidant activity test with DPPH (2,2-diphenyl-1-picrylhydrazyl) method, anticancer activity test of active fraction on Leukemia cell L1210, and GC-MS analysis to determine the active compound. Chloroform fraction has the best antioxidant activity with IC50 value 19.694 ppm (very strong category). The IC50 value of the chloroform fraction on L1210 Leukemia cells was 9.56 ppm (very strong category). Based on GC-MS analysis of the chloroform fraction, some compounds such as hexadecanoic acid, 9,12-octadecadienoic acid, linolenic acid, octadecanoic acid, androstan-17-one, and 1-(2,3,5,6-tetramethylphenyl)- ethanone were detected.
Carbon monolith from Victorian brown coal for hydrogen storage
Authors: Alfadlil B R , Knowles G P , Parsa M R , N Subagyono RR D J , Daniel  , Chaffee A L
Published: August 2019

The application of carbon monolith from VBC (Victorian Brown Coal) for H2 storage has been studied. The storage capacities of the monolith were measured using an isothermal adsorption process at different temperatures and pressures. In this study the adsorption capacities of monolithic carbon and those of activated carbon from other literature were compared. It was found that temperature and pressure affected the hydrogen adsorption capacity. It was also observed that density of the carbon monoliths can also have a significant effect on hydrogen storage capacity.
Theoretical study of the electron-withdrawing and donating groups effects on luminescent properties of the europium complexes with substituted 1,10 phenanthroline
Authors: Sudarlin  , Abdulkadir Martoprawiro Muhamad
Published: August 2019

Effects of EDG and EWG on the luminescent properties of Eu(III)1,10-phenanthroline complexes have been studied theoretically using DFT/B3LYP and TDDFT method. The 6-31G basis set was used for the ligand atoms and Stuttgart_RSC_1997_ECP for europium. The groups were varied as 2-X-1,10-phenanthroline and 5-X-1,10-phenanthroline where X is CH3; CH=CH2; F; OH as EDG and CN; CF3; NO2; CHO as EWG. The results showed that the energy difference between singlet and triplet excited state of the ligand (ΔEISC) increasing when using EDG and decreasing when using EWG. The different pattern occurs for energy difference between the triplet excited state of the ligand and the 5D0 level of europium (III) (ΔEET), which increasing when using groups without a double bond (CH3; F; OH; CF3) and decreasing when using groups with a double bond (CH=CH2; CN; NO2; CHO). The highest energy transfer rate (WET) was Eu(III)2-NO2-1,10-phenanthroline which was caused by interaction between NO2 with europium.
Type of earthworm in the banana tree habitat
Authors: Budijastuti W
Published: August 2019

The purpose of this study was to evaluate the types of earthworms found in banana tree habitat in different areas. This research method is observational research. The sampling place was chosen in the banana tree habitat with the purphosive random sampling method. Sampling areas in 4 cities (Surabaya, Sidoarjo, Gresik and Bangkalan). The results showed that there were five types of earthworms found in Bangkalan, four types of earthworms were found in Gresik and Sidoarjo, three types of earthworms in Surabaya. Conclusion there are five types of earthworms found in banana tree habitat, namely Methaphire javanica, Amynthas robbustus, Methaphire postuma, Methaphire californica, and Pheretima recemosa.
BEM solutions to exponentially variable coefficient Helmholtz equation of anisotropic media
Authors: Azis M. I.
Published: August 2019

Boundary value problems (BVPs) governed by a Helmholtz type equation for anisotropic exponentially graded media are solved using Boundary Element Method (BEM). The variable coefficient governing equation is transformed to a constant coefficient equation which is then transformed to a boundary integral equation. The results show the convergence, consistency, and accuracy of the BEM solutions.
Stability analysis of mangrove forest resource depletion models due to the opening of fish pond land
Authors: Nugraheni K , Burhan M J I , Pancahayani S , Azka M
Published: August 2019

The existence of Mangrove Forest is very necessary for the cycle of the food chain of marine fauna and its ecosystem. Balikpapan City has several Mangrove forest conservation areas that contain some rare – protected species. In this paper, a mathematical model is formulated to examine the problem of decreasing Mangrove forest resources due to the population of Bekantan (Nasalis larvatus), and the land clearing for fish ponds in the area of Mangrove forest conservation areas. The cumulative density of Mangrove forest resources and density of Bekantan (Nasalis larvatus) are assumed to follow the logistic model with predator-prey types of non-linear interactions. The main focus of this paper is to develop a Mangrove forest model derived from assumptions on the forest resource model and direct observation in the Mangrove Graha Indah forest conservation area of Balikpapan city. Furthermore, the model was analyzed using the stability theory of differential equations and numerical simulations to obtain an illustration that the cumulative density of Mangrove forest resources and Bekantan (Nasalis larvatus) would be significantly decreased if the land clearing for fishponds was not controlled.
Analysis of spatial autocorrelation of diarrhea events in East Kalimantan in 2015-2017 using a local indicator of spatial autocorrelation
Authors: Hayati M N , Purnamasari I , Wahyuningsih S
Published: August 2019

Diarrhea is still a public health issue in developing countries, one of which is Indonesia. This is indicated by an increase in diarrhea morbidity rates from year to year. Therefore, it was necessary to conduct research related to diarrheal diseases. Factors that influence the incidence of diarrhea in an area depend on the condition of the environment or the surrounding area. Spatial autocorrelation is the correlation of a variable with itself based on space or can be said similarity of objects in space, both in terms of distance, time or region. Local Indicator of Spatial Autocorrelation (LISA) is a method for measuring and identifying spatial autocorrelation locally. The purpose of this study was to determine whether there is spatial autocorrelation in the incidence data of diarrhea in East Kalimantan in 2015-2017 by using LISA testing and to determine the level of vulnerability to the incidence of diarrhea in East Kalimantan. The results of data analysis with α = 10% indicated that there were spatial autocorrelations in several districts/cities in East Kalimantan in 2015, 2016 and 2017. The results of the analysis also showed that Samarinda City and Mahakam Ulu District were categorized as prone to diarrhea.
Prediction of the number dengue hemorrhagic fever patients in district Jombang Regency using transfer function model approach
Authors: Sediono  , Tjahjono E , Maulana T D
Published: August 2019

Transfer function describes the values of future prediction from output series (Yt
) based on its past value and also based on one or more input series (Xt
) as the dependent variables. Single input transfer function model is a transfer function model that use one variable as input series (Xt
).Then, this single input transfer function model was applied to make the model and forecast the number of dengue hemorrhagic fever (DHF) cases (Yt
) in Jombang based on rainfall (Xt
). From the model, it couldbe described that the number of dengue hemorrhagic fever cases in a month was affected by rainfall on that month, rainfall two month earlier, rainfall twelve month earlier, rainfall thirteen month earlier, the number of dengue hemorrhagic fever cases a month earlier, the number of dengue hemorrhagic fever cases twelve month earlier, the number of dengue hemorrhagic fever cases thirteen month earlier, and also residual value on that month. Based on the transfer function model result, it the number of dengue hemorrhagic fever cases in Jombang could be predicted for next 20 months. After comparing the prediction result and the actual data, we obtained that almost all the prediction results (75%) were valid.
Active learning of weightlessness with the bottle-and-water-jet demonstration: Which new experiments do students propose to test an alternative explanation?
Authors: Balukovic J , Slisko J
Published: August 2019

Students learn physics better if they are involved in active learning modes, consisting of different sequences of hands-on and minds activities. The usual way of teaching weightlessness is not adequate for students’ active learning. The concept is typically introduced through “thought experiment” with a free-falling lift in which a person standing on a balance reads “zero weight”. Although some physics textbooks ask students to explain why a water jet stops to flow out of a bottle in free fall, we couldn’t find any experimental study concerned with students’ explanations of this particular demonstration of weightlessness. Therefore, we designed and carry out a corresponding research with students of primary and high schools from Bosnia and Herzegovina and Serbia. The students were asked to explain in a paper-and-pencil format why water flows out of a bottle with a hole when the bottle is at rest? Why does water stop flowing out when the bottle is in free-fall? Propose an experiment that would show that your explanation is right. What should happen in that experiment and why? The students’ answers and drawings revealed many different alternative explanations. They show that active learning of weightlessness might be possible in physics classrooms.
Interdisciplinary science concept maps to orient middle secondary school students learning outcomes
Authors: Farcas L C , Caltun I , Caltun O F
Published: August 2019

The initial and continuing training of natural science teachers should be implemented in interdisciplinary contexts. This paper shows how concept maps can generate training activities in which teachers of various disciplines can discuss macro concepts such as water, air, wind, temperature, motion, power, energy, etc. mapping the students’ learning pathway. Drawing concept maps and discussing them in training sessions from the perspective of students, teachers and trainers can be a decisive professional experience in changing the ways of improving concepts representations of all the actors of classroom activities and educators.
Magnets and magnetic field around them: what can we learn from simple experiments
Authors: Dvořák L
Published: August 2019

Small neodymium magnets are useful tools enabling us to do a lot of experiments usable in physics teaching and learning. Simple experiments with these magnets can be done quickly and at minimal cost. Such experiments are usually used to demonstrate or investigate just qualitative features of magnetic field. However, simple experiments, when combined with small pieces of theory, offer much more than that. In the workshop, the participants went from very simple qualitative observations to experiments that, being still simple and low-cost, enable the measurement of the force between magnets and even to estimate the value of magnetic field B inside magnets and around them. The workshop was led in an inquiry-based style and offered a teaching-learning sequence that teachers can adapt for various levels of schools.
Space mishap as a stimulus context for thermal conduction exploration in secondary school
Authors: Komáromi A
Published: August 2019

A large body of literature underlines the relevance of personal involvement and in-context assignments in increasing student engagement in physics education at secondary level. The research-based teaching/learning experience offers different kinds of suggestions for physics education on the level of curricular proposals, on the level of feasibility of inquiry-based learning approaches, on the level of strategies and methods for learning environment settings, and on the level of conceptual understanding of students. During the activities, students find a good opportunity to discuss how heat is transferred, both on Earth and in space. Students discover through their own exploration what types of radiation space objects are exposed to in near-Earth orbits. By means of a “flipped classroom” methodology the students analyse radiant heat absorption and reflection. The activity was extended to learn about heat radiation incident on Earth and emitted by Earth. It was interesting to see the reaction of students when they realized that “radiant heat” has a wavelength, and that it is part of the electromagnetic wave spectrum. Tutorials and post-tests were used in order to gauge the students’ understanding of the processes involved, and in particular what their conception of heat is. Students proposed different materials for heat shields used in the experiment, and in this way we touched on the subjects of thermal insulation and heat capacity. This leads us to examine the inner structure of materials, and essentially the link between macro- and micro-world. Discussion of heat absorption is a way to introduce the concept of energy, and consequently the role of macro-micro models in material science processes description. Characteristics and main results of the intervention module will be presented together with data of the monitored learning process.
Developing second level students’ understanding of the inverse square law and electric fields
Authors: Moynihan R , van Kampen P , Finlayson O E , McLoughlin E
Published: August 2019

There are specific mathematical tools involved in building an accurate model of introductory electric field theory. Algebra operations, vectors, field lines, proportional reasoning and the inverse square law are all integral parts of gaining a complete understanding of an electric field. In this paper we present a small body of research, taken from a case study with a group of 14 upper second level students, in which they developed their understanding of the inverse square law, using a pre-test-tutorial-post-test tutorial lesson model. Students struggle to understand the inverse square law unless they are repeatedly exposed to it. Using the context of intensity, our students develop their understanding of the inverse square law using a variety of representational forms, such as diagrammatic, tabular / graphical and calculations using formulae. Using our pre-test and post-test results, our students showed gains in their reasoning used to explain the variation of intensity when an object is moved various distances from a source, which we attribute to their reasoning developed in the tutorial lessons. Additionally, students completed quantitative problems involving the inverse square law in the context of Newton’s gravitational law. Six weeks after the completion of the inverse square tutorial, our students completed a tutorial lesson, in which they applied their understanding of the inverse square law to Coulomb’s law and the electric field. Our results show that our students could apply the inverse square law to these contexts when guided, but some difficulties still remained, such as proportional reduction / increase based on variation of the distance, and transfer between representations, such as algebraic to graphical.
Flipped classroom in secondary school physics education
Authors: Finkenberg F , Trefzger T
Published: August 2019

This quasi-experimental pre/post-study with control group examines the effect of the flipped classroom method applied to basic physics courses at two German secondary schools (N = 150) in a three-month treatment. The focus of the study is the performance in a content knowledge test and the related non-cognitive attitudes as interest in the subject physics, motivation to do physics and the physics related self-concept. First results indicate that flipped classroom has a positive effect on the learning gain as well as on motivation and self-concept. Further analysis will look into parameters that moderate the effect of flipped classroom.
Collaborative Group Learning in a Swiss introductory physics class
Authors: Feldman G , Schiltz G , Vaterlaus A
Published: August 2019

We report on the implementation of the SCALE-UP collaborative pedagogical approach in a first-year undergraduate physics class at ETH Zürich. The performance of the students on various assessments was compared with identical assessments in a parallel lecture class in order to gauge the effectiveness of this approach. Surveys were also given to get feedback on how students were reacting to this innovative style of pedagogy.
Light the world and change its color: A case study in Italian secondary school using IBSE methodology
Authors: Adesso M G , Capone R , Del Sorbo M R , Fiore O
Published: August 2019

What color is it? It is not a trivial question: answer depends on the lamp used to light the world! Let’s fix a light and measure with our human instruments, eyes and ears, a colored and orchestral environment: may we distinguish, at the same time, all the colors and sounds? Here we show a case study using Inquiry Based Science Education (IBSE), a teaching methodology, focused on the wave-matter interaction in daily experience and some ways to detect it by our senses. IBSE methodology engages students eliciting investigation of physical phenomena. General expected outcomes are an improvement of students’ motivation and a more successful learning experience. We planned an educational path, based on investigation, for students attending the first year of high school. The course has been developed in four lessons (2.5 hours each) for a total of 10 hours. This path has been experimented in four different parallel classes. In each class, students have been divided into 5 or 6 groups. The first phase, “engage”, is a simple trick: try to guess the color of four cards lighted with a monochromatic beam, red, blue, or green, in the dark. Once a white light is turned on, students will be surprised to see the true colors of the cards. After this “engagement”, students “explore” interaction between wave and matter, accomplishing some tasks and trying to “explain” the observed phenomena. The third and most important step is to “extend”: students directly experience additive color synthesis, with attention to pointillism, to subtractive color synthesis, and to superposition of sound. Later, each group, as in a flipped lesson, looks for answers to preliminary questions, by investigation: ear and eye behaviour, differences between electromagnetic and sound waves, electromagnetic spectrum. ICT is a valuable support in this phase. A multimedia product is requested at the end of investigation. In order to “evaluate” this educational path, it has been proposed to think about the use of a monochromatic lamp to change a colored word in another one, without some yellow and red letters. A feedback questionnaire has been also used to evaluate the educational path. The results of the questionnaire show that students are satisfied with this new methodology and activities. Satisfactory results, however, depend upon teacher’s ability to motivate all students in attending classes.
Some reasons that influence dropout in a Physics Teachers Training program
Authors: Kussuda S R , Nardi R
Published: August 2019

There currently exist several countries experiencing problems related to the lack of teachers, as indicates the Organization for Economic Cooperation and Development. Part of this problem is related to the quantity of students that dropout teacher training programmes, reducing the quantity of teaching workforce. We conducted a research to understand the main reasons to former students to dropout a physics teachers training programmes. To obtain the data we applied an online questionnaire with 274 former students, 37 of them answered the questionnaire. Although this number represents 13.5% of the total, the main answers are recurrent, indicating that those could be similar to other former students. Through the analysis of the answers was possible to note that, although this physics’ teaching programme may be considered difficult among former students, such difficulties seem to be related to several factors, beside the complexity of the Physics as need to work during the morning or the demotivation that occurs within this programme. We argue that the dropouts seem to be more related to problems such as the pedagogical performance of the professors of Higher Education, than difficulties related the complexity of Physics.
Study of the implantation of an experiential approach to science teachers’ training in Francophone minority communities: results from the second phase of a three phases design research
Authors: Trudel L , Métioui A
Published: August 2019

To remedy the problems of science teaching in francophone minority communities in Canada, we propose an “experiential” approach to train future science teachers. In this regard, our research aims to conceive and identify the conditions for implementing such experiential training, as well as evaluate its effect on the development of science teaching skills, as part of a collaboration between a university education faculty and two high schools in a French minority environment. The experiential approach had been implemented in one physics education course in a teacher training program taught in a Canadian university. To assess the achievement of our research objectives, we used qualitative methods, following a design research model. We report here on the results of the second phase of a three phases design research process. As for the implantation in local minority settings, some key findings are reported here from the second phase. Finally, we conclude by stating advantages and limits of our research.
Seeking co-production of knowledge in alternating training: insights from DESCI first round of world cafés
Authors: Valente A , Pennacchiotti C , Smyrnaiou Z , Kotsari K , Petropoulou L , Tudisca V , Ricci F L
Published: August 2019

In the last years the debate on competences and their role in the development of a more inclusive societies and in promoting innovation processes has become increasingly crucial at European level. The European Commission identified 8 key competences (basic and transversal competences and soft skills) that have to be attained by all citizens during their learning process. Also employers require from their employees more and more these kind of skills, and this is true also in the scientific education and research context. Indeed “Communication, working with others, problem solving and other similar abilities are considered very important requisites for a recently graduated student by a large section of the research laboratories responsible.” Nevertheless, European school curricula bestow little attention to transversal competences and soft skills. In this framework DESCI1 project, funded by Erasmus + Program, aims to develop a methodological pattern for alternating training in secondary school systems, adopting participatory design methodologies based on a Living Lab environment, to improve the connection between school, research, enterprise and territory and to promote the development of soft and transversal skills in students, needed to allow them to foster the innovation process, to increase their employability, express themselves, acting consciously in the system and driving the innovation and social inclusion in their communities. The DESCI approach undergoes to a continuous and participated evaluation process, under RRI principles, meant in order to explore, in a process of co-creation of knowledge, the ongoing results of the project. The evaluation outputs emerged at this stage of the project confirm that, in the learning AT process, the DESCI approach promote the increase of transversal competences and soft skills in the students, mainly referring to those included in the 8 key competences identified by the EU Commission.
Conceptual metaphor in physics education: roots of analogy, visual metaphors, and a primary physics course for student teachers
Authors: Corni F , Fuchs H U , Dumont E
Published: August 2019

We show in what sense macroscopic physical science is a product of figurative (imaginative) structures of the human mind. Conceptual structure in physics is perception based and schematic and uses metaphoric, analogical, and narrative forms to extend direct perception and conception to cases of less directly accessible phenomena. For instance, a theory of the dynamics of heat can be rendered in a form analogous to that of fluids or electricity. We show how tools using visual forms of metaphors employed in macroscopic physical science can be designed and applied, and we briefly outline one application of the principles discussed here: a novel course for kindergarten and primary school student teachers.
Economical Comparisons of Interconnection Technology for Asynchronous AC Power Grids
Authors: An Byeonghyeon , Jeon Jin , Lee Minho , Park Taesik
Published: August 2019

There is growing interest in grid connections between different micro grids, countries, and the selection of interconnection method should be based on an economic analysis. This paper analyses the economics of VFT (Variable Frequency Transformer) and HVDC (High Voltage DC) and proposes an optimal grid interconnection method. The economic evaluation was conducted based on the new investment cost depending on the capacity of the facilities needed for the grid connection, and the feasibility study was carried out to find out which method is more advantageous economically.
An Integrated Energy Power Generation with Energy Storage System
Authors: Zhang Peng , Wang Yize , Wang Wei
Published: August 2019

How to consume new energy power generation is a very common problem, If we don’t take effective measures, the situation will become more and more serious. Through the application of new energy generation and storage energy management technology, can enhance the level of intelligent low voltage distribution with effectively alleviate this problem. This paper studied the basic control theory of new energy generation and storage system energy management technology, the software support platform based on dispatching automation, to advanced applications as a means to embody the control strategy, research and development of new energy generation and storage system to the management, provide technical support and the effective guarantee for the safe and stable operation of new energy power generation.
Numerical Investigation for the Arrangement of Perforated Tile under a Non-uniform Heat Source Condition in a Raised-floor Data Center
Authors: Huang Jianwen , Chen Cheng , Guo Guiyang , Zhang Zhang , Li Zhen
Published: August 2019

The research object of this paper was a typical raised-floor data center where the heat load of each rack was non-uniform. The non-uniform heat source caused that the temperature field in the room was also non-uniform and part of the rack outlet temperature was relatively high. In view of this problem, a numerical simulation was conducted to investigate the effect of the arrangement of perforated tile on the air distribution and the temperature field. The results indicate that a better arrangement of perforated tile could optimize the air distribution and make the temperature field in the room more uniform. The maximum rack outlet temperature was reduced by about 2.1°C under the proper condition of the tiles opening ratio, which means that the energy efficiency of the cooling system was accordingly improved. The adjustment of the tiles opening ratio could be a solution to the non-uniform heat source problem in a raised-floor data center.
An economic analysis of the solar photovoltaic/thermal (PV/T) technologies in Sweden: a case study
Authors: Zhang Xingxing , Wu Jinshun , Pan Song , Han Mengjie
Published: August 2019

The solar energy share in Sweden will soar over the next decades. Such transition offers not great opportunity but uncertainties for the emerging solar PV/thermal (PV/T) technologies. There are still critical challenges for PV/T development in Swedish scenario. This paper aims to investigate the local policies and market structures in Sweden by a set of analytical economic frameworks and a case study. A macro-economic exposure analysis in Swedish context is conducted and a PEST model is then applied for analysis of external environment of PV/T industry in Sweden. The PV/T market is further analysed based on a case product by means of SWOT and Porter’s five forces. The whole study concludes that the market of solar PV/T is expanding mostly towards small-and medium-sized energy plants. The market position of the case company meets the trend of PV/T market, which has an overwhelming competence against its competitor in the domestic market. This paper is expected to clarify the economic situations of PV/T in Sweden and promote its further development towards sustainable and low-carbon economics.
Experimental study on the thermal performance of ethylene-tetrafluoroethylene (ETFE) foil cushions
Authors: Flor J-F , Sun Y , Beccarelli P , Rowell C , Chilton J , Wu Y
Published: August 2019

ETFE pneumatic foil constructions are used increasingly by designers and builders as an alternative to glass in state of the art building envelopes. Low weight, high transparency, mechanical resistance and self-cleaning properties of ETFE may contribute to the overall performance. However, reliable information on the thermal performance of ETFE cushions in building envelopes is scarce, limiting the performance prediction in energy simulations. The present study aims to investigate the thermal performance of air-inflated ETFE foil cushions and evaluates parameters of material properties and design which might affect the thermal transmittance. The paper reports on the experiments conducted to quantify the thermal performance using a climate chamber and full-size mock-ups. Based on available standards, tests were designed to compare the thermal performance of three different ETFE cushion designs, under changing climate conditions. The design variations, including frit prints and switchable shading mechanisms, were tested and compared at hot, temperate and cold weather scenarios. The test series provided detailed results on the thermal performance of ETFE cushions which may be of use for the comparison with the performance of other building components and materials, serve as input for energy simulations and provide a theoretical basis for future developments of novel building envelopes.
Annealing temperature dependence of properties of CdSe thin films by RF-sputtering
Authors: Wang Ailing , Li Chunxiu , Zhang Jingquan , Wu Lili , Wang Wenwu , Feng Lianghuan
Published: August 2019

Cadmium Selenide (CdSe) is a II-VI group compound semiconducting material with a direct band gap about 1.74 eV, which is widely applied in thin film transistors, light emitting diodes and photoelectrochemical (PEC) cells. In recent years, the application of CdSe thin films to CdTe thin film solar cells has attracted the attention of people. CdSe thin films were synthesized using radio frequency magnetron sputtering method on Corning glass substrates at room temperature. The as-deposited films were annealed at various temperatures (200°C, 300°C, 400°C and 500°C) in N2 atmosphere for 1h and the effect of annealing temperature on structural, morphological, compositional, optical and electrical properties was studied. X-ray diffraction (XRD) indicates that the structure of CdSe thin films transforms from cubic to hexagonal structure when annealing temperature changes from room temperature to 500°C. Scanning electron microscope (SEM) images show that the crystallite size of CdSe thin films has no obvious increase with annealing temperature increasing from 200°C to 400°C, which is all about 33 nm. However, grains with size of 200 nm were precipitated on the surface of CdSe thin film annealed at 500°, and the Se content of CdSe thin film decreased. The band gaps of CdSe thin films were found to firstly decrease, and then gradually increase with the increase of annealing temperature. The minimal band gap of CdSe thin film is 1.63eV when annealed at 300°C. The conductivity of CdSe thin film annealed at 500° increased by two orders of magnitude compared with as-deposited CdSe thin film.