bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reemergence of superconductivity by 4d transition-metal Pd doping in over-doped 112-type iron pnictide superconductors Ca0.755La0.245FeAs2
Authors: Xing Xiangzhuo , Li Zhanfeng , Veshchunov Ivan , Yi Xiaolei , Meng Yan , Li Meng , Lin Bencheng , Tamegai Tsuyoshi , Shi Zhixiang 
Published: August 2019

Abstract
In 112-type iron-based superconductors (IBSs), rare earth (e.g. La) doping enhanced antiferromagnetic (AFM) order and 3d transition-metal (e.g. Co, Ni) doping induced reemergence of superconductivity (SC) in the over-doped regime (non-SC) are of particular interest, providing a significant opportunity to further understand the relationship between SC and AFM order in IBSs. Recently, 4d transition-metal Pd-doped 112-type Ca1-y
La
y
Fe1-x
Pd
x
As2 (x > 0.2, 0 ≤ y ≤ 0.3) compounds, which crystallized in new orthorhombic and tetragonal structures, have been identified (Inorg. Chem. 56 3030 (2017)). However, none of them exhibit SC, probably due to the oversubstitution of Pd for Fe. Here, to reveal the impact of slight Pd doping on the over-doped Ca1-y
La
y
FeAs2 and compare to 3d Co/Ni doping series, single crystals of Ca0.755La0.245Fe1-x
Pd
x
As2 with 0 ≤ x ≤ 0.08 are successfully grown using the self-flux method. We find that, upon only a small amount of Pd doping (x = 0.013), bulk SC with a maximum T
c of 28.5 K is reemerged, in contrast to the case with high Pd doping level. Moreover, based on the electrical resistivity and magnetization data, we construct the temperature-composition (T–x) phase diagram, the shape of which, particularly for the region where the AFM and SC phases coexist microscopically, is almost identical to that of Ca0.76La0.24Fe1-x
Ni
x
As2, but is distinctly different from that of Ca0.74La0.26Fe1-x
Co
x
As2, presumably due to the presence of complex doping mechanism in 112-type IBSs. Finally, for one selected single crystal with x = 0.013, superconducting properties including critical current density, vortex pinning mechanism, and vortex diagram are systematically studied by magnetization, magneto-optical imaging, and magneto-resistivity measurements. Our work provided more insight into the phase diagrams and superconducting properties of 112-type IBSs, allowing better understanding of its superconducting mechanism and developing the potential applications.
Students’ ability to analyse empirical data in practical work
Authors: Pols C F J 
Published: August 2019

Abstract
Although students in upper secondary education are often asked to carry out practical work independently to a large extent, it is questionable whether they already have the knowledge to do so successfully. This study looks into the data analysis skills students aged 15 should possess according to various curriculum documents and investigates whether this is the case. To do so, the 51 students involved carried out two practicals using worksheets with questions in which they ought to apply each of the ten identified data analysis skills at least once. The analysis of their work shows that students master the skill of visualising data in graphs. In applying each of the other skills, students make many mistakes or do not know what to do or how to proceed. Students do not have a preconceived plan but work mostly ad hoc. They are able to draw valid but superficial conclusions which could have been drawn without an extensive 50 minute practical. Their lack in data analysis skills may result in not attaining the learning goals set in other practicals. Students thus should be taught how to analyse empirical data, the practicals used in this study may serve as a basis for this.
Relativity of simultaneity in secondary school: an analysis based on the Theory of the Conceptual Fields
Authors: Otero María Rita , Arlego Marcelo , Muñoz Edwin 
Published: August 2019

Abstract
In this paper, we present results about the conceptualization of the relativity of simultaneity and the operational invariants used by high school students. The Theory of Conceptual Fields is adopted to design, analyse and evaluate a didactic sequence to teach the basic aspects of the Theory of Special Relativity in secondary school. Only the situations related to the relativity of simultaneity are analysed here. An inductive categorization is constructed from 256 protocols generated in the implementations carried out in four 11th grade courses (15-16 years) (N = 128) in a public school of Colombia. The categorization identifies the resolutions of the students and the operative invariants that they use in each situation. The results indicate that the proposed situations would produce the emergence and awareness of the operational invariants linked to the relativity of Galileo, which would open the way to the conceptualization of the relativity of simultaneity in secondary school.
Navigating four dimensions – upper secondary students’ understanding of movement in spacetime
Authors: Kersting Magdalena 
Published: August 2019

Abstract
In contrast to classical physics, general relativity (GR) interprets gravity as geometry. Objects follow geodesic curves in four-dimensional spacetime and curvature creates the illusion of a gravitational force. Despite the scientific relevance of this theory, educational research in the domain of GR is scarce. This study contributes to a growing body of knowledge concerning secondary students’ understanding of GR. Based on a thematic analysis of audio records of student discussions of 97 Norwegian physics students (18-19 years), we present results on students’ understanding of geodesic movement in spacetime. Our findings can give guidance to improve learning and instruction of a key concept of GR at the upper secondary school level.
Embedding Diagrams - a Hands-on Activity for Understanding Spatial Curvature
Authors: Ryston Matěj 
Published: August 2019

Abstract
Even the basics of General Relativity are considered difficult for students due to its abstract nature and the lack of concrete demonstrations suitable for a typical classroom. One area that offers some possibility of hands-on activities for students are embedding diagrams, the curved surfaces that we use to illustrate spatial curvature. Plastic models of these surfaces can easily be made using a 3D printer, which is a piece of equipment that is rapidly becoming more and more available to schools and even students themselves. In this contribution, we will propose a chain of activities, with some of which the reader might already be familiar, meant for students to help them understand what spatial curvature is and how it relates to the motion of planetary bodies (not only) in our Solar System.
Infrared vision of artworks based on web cameras: a cross-disciplinary laboratory of optics
Authors: Daffara Claudia , De Manincor Nicole , Perlini Luca , Bozzo Giacomo , Sapia Peppino , Monti Francesca 
Published: August 2019

Abstract
Applied optics offers a way to teach fundamental concepts of light properties and radiation-matter interaction through interdisciplinary experimental activities. In this framework, we designed a cross-disciplinary laboratorial activity on optics applied to artworks based on DIY instrumentation for the secondary school level. The teaching sequence includes inquiry-based seminars and laboratorial activities on imaging, spectrometry, infrared applications to conservation science.
Collaborative Learning vs. Lecture for Introductory Physics Students: A One-Year Longitudinal Study
Authors: Feldman G , Schiltz G , Vaterlaus A 
Published: August 2019

Abstract
A collaborative group-learning classroom was implemented on a trial basis at ETH Zürich in the Spring 2017 semester. Data on conceptual understanding, problem-solving ability, and student feedback were collected from the class and compared to a parallel large lecture class. In addition, a comprehensive Final Exam was given in January 2018 to assess the overall learning achievements of the students in both sections. These comparative data will be presented in order to gauge the effectiveness of the collaborative pedagogical approach.
Highly precise analytic solutions for classic problem of projectile motion in the air
Authors: Chudinov Peter , Eltyshev Vladimir , Barykin Yuri 
Published: August 2019

Abstract
Here is studied a classic problem of the motion of a projectile thrown at an angle to the horizon. The number of publications on this problem is very large. The air drag force is taken into account as the quadratic resistance law. An analytic approach is used for the investigation. Equations of the projectile motion are solved analytically. All the basic functional dependencies of the problem are described by elementary functions. There is no need to study the problem numerically. The found analytical solutions are highly accurate over a wide range of parameters. The motion of a baseball and a badminton shuttlecock is presented as examples.
Visual and gestural metaphors for introducing energy to student teachers of primary school and kindergarten levels
Authors: Corni Federico , Fuchs Hans U. , Landini Alessandra , Giliberti Enrico 
Published: August 2019

Abstract
The linguistic expressions scientists and educators use for energy are in most cases expressions of the principal metaphor of substance, although energy is an imponderable concept. The substance metaphor is embodied and familiar to students, so we can rely on it as useful for helping them develop a productive framework for understanding energy.
In this paper we will introduce a laboratory course for student teachers of primary school and kindergarten levels using visual and gestural metaphors for introducing energy,
TSPK and beliefs about teaching and learning electricity in lower secondary: A comparison between teacher students and first year teachers
Authors: Schubatzky Thomas , Haagen-Schützenhöfer Claudia , Krumphals Ingrid 
Published: August 2019

Abstract
The relationship between teachers’ beliefs, topic specific professional knowledge (TSPK) and their teaching practice has driven research in the field of teachers’ professional knowledge for the last decades. Currently in Austria teacher education programmes and induction phases are reformed. In the course of the development of new curricula and courses knowledge about their quality and effectiveness is essential. Therefore, appropriate test-instruments are needed. This contribution presents results of a pilot study focusing on teacher students and first-year teachers TSPK and beliefs. In order to investigate whether and to what extent TSPK varies between teacher students and fully educated teachers, the presented study focuses on the comparison of TSPK-test results of pre-service teachers and first year teachers in Austria. Additionally, the relationship between TSPK, beliefs and knowledge of the Nature of Science was investigated.
Teaching Critical Thinking in the physics classroom: High school students think about antimatter
Authors: Sadidi Farahnaz , Pospiech Gesche 
Published: August 2019

Abstract
Teaching students the skills that they need for everyday life like Critical Thinking (CT) is the goal of education. Embedding Critical Thinking skills within a content-specific instruction is expected to improve students’ critical-thinking skills. In this article, we present our content-specific instructional design for promoting students’ critical-thinking skills. The target group comprises German high school students of grades 11 and 12. The specific topic of learning modules is antimatter. To design the instruction, we combined the model of “First Principles of Instruction” with our domain-specific interpretation of Halpern’s general definition of Critical Thinking skills. To develop and optimize our instructional design, we use Design-Based Research cycle.
Science Club activity at Székely Mikó High School
Authors: Pető M 
Published: August 2019

Abstract
The aim of the Science Club is to organize workshops that improve the technical and IT competence and skills of students. These transcurricular activities are based on STEM topics, Arduino applications, robotics and space research, which are not included in the school curricula. Through these activities, students are acquainted with the latest results of science and technology, which they can apply in practical workshops. The achievements of the Science Club (Arduino controlled meteorological station, minisatellite, rescue and fire robot, etc.) show that these activities can motivate students to participate more effectively at classroom activities in order to learn theoretical subjects and later choose a career in this field.
Numerical Study on Enhancing Heat Transfer of the Belt-type Resistance Heater in the Hypersonic Wind Tunnel
Authors: Mao Qing , Chen Jiufen , Xu Xiaobin , Fan Xiaohua 
Published: August 2019

Abstract
Numerical studies of Heat transfer enhancement of belt-type Electric-resistance Heater is reported in this paper. The effect of different kinds of belt arrangements is studied in detail. Results show that, for changing m and n, which is the spacing between adjacent belts both in vertical and horizon, the comprehensive Performance Evaluation Criterion(PEC) increases as belt spacing decreases; For the case of model adding several baffles, the PEC reaches 1.6, with Nu/Nuo and f / f0
comes to 3.38 and 9.51; For the staggered arrangement belt geometry, the PEC attains 1.18 and the flow field uniformity improves significantly compared with the aligned arrangement one.
Optimization of duct structure and analysis of its impact on temperature inside the shelter
Authors: Lu Jiawei , Wang Tao , Wang Liangmo , Chen Wei , Chen Yandong 
Published: August 2019

Abstract
The flow field of the air duct in a shelter was studied using the computational fluid dynamics (CFD) and experiment methods. The improvement methods of vortexes at the bends were analysed. It was found that the corner chamfer and the installation of guide plates have significant effect on improving the vortex. The optimized scheme expanded the inlet and outlet area of the air duct and chamfered the inner bends, then the uniformity of velocity at outlets on both sides of the straight duct was increased by 47% and 42% respectively. The duct was placed in the shelter for simulation. The results showed that the total air volume of the air duct has increased, so the cooling effect is better. The temperature distribution in the shelter is more uniform after optimization, especially in the front part due to the improvement of vortexes.
Comparative Study of Free Vortex and Random Vortex in the Design of Wind Tunnel Axial Fan
Authors: Geng Zihai , Cai Jinsheng , Huang Zhilong 
Published: August 2019

Abstract
The design methods of axial flow fan mainly include free vortex design method and random vortex design method. The random vortex design method and free vortex design method were used to design aerodynamic parameters of two fan systems, and then the performance of these two fan systems was compared by numerical simulation. In the numerical simulation, the random vortex method and free vortex method are applied, respectively, based on the fan design parameters given by the acoustically guided wind tunnel fan section, and the physical model was established, the numerical simulation comparison study was conducted for the two sets of fan systems. The comparative analysis of the numerical simulation results shows that compared with the free vortex method, the fan designed by the random vortex method can reduce the local separation of tip and root of the blade, and the axial velocity distribution of fan blade and fan section outlet can be more uniform, and there is a certain increase in fan blade efficiency. These results verify that the design method of random vortex fan is feasible in large wind tunnels, especially in wind tunnels with aerodynamic noise reduction requirements, and can provide powerful conditions for optimizing aerodynamic and acoustic performance of the fan.
Research on the temperature field model of plate hot rolling process based on CUDA
Authors: Liu Wenhong , Guo Siying , Zhang Siyu 
Published: August 2019

Abstract
The current temperature field model of plate rolling process is generally based on CPU programming, due to the influence of computer performance, the accuracy and speed of the model can not be improved at the same time. To solve this problem, this paper studies the temperature field model with particle swarm optimization to modify the heat transfer coefficients, and the parallel program of this model is written under CUDA architecture, on premise of ensuring the accuracy of the model, the computation speed of the model is improved. To get the best acceleration, this paper analyzes the factors affecting GPU performance, the accuracy and speed of the temperature field model before and after modification are compared under the best acceleration configuration. Final temperature field model calculation error reduced to an average of 15.57 °C, better than the model based on the empirical formula, the computing speed is also improved, which is 1.78 times that of CPU.
Clothing Design Model for High Temperature Work based on Heat Conduction
Authors: Wang Zhenzhen , Feng Shaofen , Chen Hongyu , Chen Xueyue , Zhou Shijie , Pan Wenwen 
Published: August 2019

Abstract
By analyzing the temperature changes of the three-layer high-temperature clothing and the air layer of the fourth layer, according to the calculation of the temperature distribution of the high-temperature clothing, the temperature changes of the high-temperature clothing are related to the heat, ignoring the heat transfer of heat radiation in the clothing and the internal heat sources between the layers, defining three variables of time, temperature and thickness, according to the law of conservation of energy and Fourier’s law of heat transfer. The law obtains the heat conduction equation. The forward difference method in the finite difference method is used to solve the equation, and the numerical model is obtained. Then, the relationship diagrams of temperature, time and thickness are drawn. The experimental results show that the heat absorbed by the outside is consumed layer by layer in the process of heat transfer, and finally the air layer contacted with human body tends to 48 C. Finally, according to the formula Q = cm Delta U of heat absorption in physics, further analysis is carried out, and the optimal thickness of Layer II and Layer IV is obtained by using the optimization algorithm.
Study on Flow Field Optimization for SCR System of Coal-fired Power Plants
Authors: Liu Xiuru , Sun Yiqing , Xue Fangming , Su Jingcheng , Chen Feng 
Published: August 2019

Abstract
Coal-fired power plants are undergoing ultra-low emission retrofits. When the flue structure of the SCR denitrification system of the existing unit is fixed, the internal baffles and static mixers need to be optimized to ensure the flow field uniformity, thus ensuring the denitrification efficiency and controlling the ammonia escape rate. For a 660 MW SCR system, numerical simulation of flue gas flow uniformity and cold state test of physical model were carried out. The results show that the uniformity of the flow field distribution and the mixing effect of ammonia and gas in the SCR denitrification system are effectively improved by adding deflectors and optimizing the static mixers. The research in this paper provides reference for similar engineering design and construction in the future.
Radiative Heat Flux of a Burning Crude Oil Tank to the Adjacent Tank under the Conditions of Varied Wind Flows
Authors: Zhou Feng 
Published: August 2019

Abstract
Simulation about the large-scale crude oil tank fire is conducted. By utilizing the FDS to simulate the 105m3 crude oil tank fire and gaining the feature of the flame under four different wind conditions, the incident radiation distribution of the flame on the adjacent tank is acquired. The cylindrical flame radiation model is used to simplify the flame and the radiation simulation is conducted with COMSOL software. It suggests that the wind condition influence the incident radiation distribution as well as the radiation intensity. In the same wind condition, the position and the incidence angle hold different effect on radiation distribution. Finally, according to the characteristics of incident radiation, some suggestions are proposed for firefighting.
The stall of different ice accretion airfoil
Authors: Feng Yupeng 
Published: August 2019

Abstract
Ice along the leading edge of upper surfaces have detrimental effects on performance and control of an aircraft. Various icing shapes airfoil have various influence on aerodynamic characteristics and stall phenomenon. The mechanics model, of which ice accretion zone is on the leading edge, is produced by the assembly of various ice shapes (rime ice and mixed ice) and NACA0012 airfoil, In order to analyse the cause of stall phenomenon. The Reynolds averaged Navier-Stokes (N-S) equations are solved using Spalart-Allmaras (S-A) turbulence models the entire flow field. The results show: 1) the stalling angle of attack is various in case of various ice shapes on the leading edge. The stalling angle of attack is 15.5° in case of none ice, about 9° in case of rime ice and about 7.8° in case of mixed ice. 2) The way of airflow separation is different in case of various ice shapes on the leading edge. The vortex zone is expanded from the trailing edge to the leading edge in case of rime ice. Both vortex zones at the leading edge and the trailing edge are expanding meanwhile into one vortex zone in case of mixed ice.
Airflow Inclination Sensor Based on Temperature Field
Authors: Zheng Yonghong , Peng Shiliu , Xiao Wei 
Published: August 2019

Abstract
It is the temperature field of the closed cavity that plays a decisive role in sensitive inclination. With numerical simulation of ANSYS, the temperature field was analyzed separately under the environmental temperature and heat source temperature unchanged. When the temperature difference between environment and heat source remains constant, the temperature gradient of flow field remains invariant. A circuit can be designed so that the temperature difference between the environment and the heat source does not change during the operation of the inclination sensor, and improving the stability of sensor performance further with the circuit.
Study on the influence of pumping system on the hydrodynamic performance of air tanker
Authors: Xiao Zhijian , Wang Lili , Huang Miao , Jiang Rong , Wan Yuxiang 
Published: August 2019

Abstract
The influence of the pumping system on the hydrodynamic performance of the air tanker were investigated in this paper. The hydrodynamic performance of the air tanker with different displacements under the different Froude numbers was studied by experimental method. RANS methods and overset mesh were used to compute the viscous flow field of an air tanker under three conditions at different Froude numbers. Numerical method adopted in this paper was verified and validated by comparing the experimental results with the simulation results. The experimental results showed that the total resistance and the heave amplitude of air tanker with different displacements increased, while the pitch angle decreased, as the speed increased. And the larger the displacement, the greater the total resistance, pitch angle and heave amplitude. The simulation results showed that the drainage efficiency, the load of the baler and the additional pitching moment showed non-linear growth with increasing speed. As the baler lowered, the total resistance and heave amplitude of the aircraft increased, but the pitch reduced. The effect on the hydrodynamic performance of air tanker was not obvious as the baler closed.