bluuebunny/crossref_metadata_2025_split huggingface dataset:
Millimetron microvibration analysis at low frequency range
Authors: Kravchunovsky A P 
Published: June 2021

Abstract
This paper presents the results of Millimetron microvibration analysis at low frequencies. Millimetron telescope structure behavior was studied in order to predict its central mirror response from microvibration disturbance caused by mechanical cryocoolers. The results contain the most significant values of acceleration which appeared on the mirror surface as well as rotational deflections which affect the telescope optical axis stability. To make it possible the microvibration analysis technique was derived from the theoretical aspects and other researches results. This technique was adapted to Millimetron microvibration analysis using its finite-element model and taking into account several assumptions which were also discussed at this paper.
Creation of a joint group and a decision support system to improve the after-sales support of civil aircraft
Authors: Zryachev S , Larin S 
Published: June 2021

Abstract
This work focuses on the problems of the existing approach to servicing Russian civil aircraft. The work aims to create a joint group for the analysis and processing of after-sales support flows, working together through the decision support system. The main difference from the current approach is the continuous joint work of all participants of the after-sales support, as well as the automated processing of the information received at all stages of the life cycles of aircraft. The work with a decision support system is presented as a work of joint group and operators through a decision support system. The presented methods and algorithms are the basis for increasing the competitiveness of Russian civil aircraft on the world market.
Accuracy of the short fibers reinforced composite material plasticity models
Authors: Kurkin E I , Spirina M O 
Published: June 2021

Abstract
Composite materials reinforced with short high-strength fibers are used in the aerospace industry, due to their high specific stiffness and strength. The anisotropic nonlinear nature of a short fiber reinforced composites requires the usage of anisotropic plasticity model of the material representative volume mechanical characteristics to predict the stress-strain state of the molded products. In this work, was made a comparison of three models of binder hardening – power, exponential and linear-exponential laws. The models were built in the Digimat MF system. The models describe tension of ISO 527-2 samples of 50% short glass-fiber reinforced polyamide PA6, cut out from plate at angles of 0°, 45° and 90° to the molding direction. The models parameters were identified by reverse engineering in the Digimat MX. The paper gives estimates of the accuracy of approximating the plasticity curve in each tension direction by the investigated models. The influence of the Mori Tanaka and the double inclusion homogenization schemes is investigated. It is shown that the exponential hardening law makes the best tension curve approximation with mean relative error less than 3.8% and maximum relative error less than 9.7%.
Improvement of the architecture of a universal robotic platform designed for swarm structures basis of small unmanned aerial vehicles
Authors: Pasechnikov I , Vospitanyuk A , Nazarov A , Rybakov D 
Published: June 2021

Abstract
The model of the landing system for swarms of small unmanned aerial vehicles in fact consists of a queuing system with a space-time holding zone serving as a gathering device for small unmanned aerial vehicles, where the holding elements are represented by the sequentially connected buffer zone for aerial vehicle landing and the landing line itself with a robotic landing platform. The passage of aerial vehicles from the holding area to the landing zone is controlled by the landing line access protocol. Safe movement of small unmanned aerial vehicles in the holding and landing zones is ensured by the information-measurement and management landing system of a universal robotic platform. The article suggests using the “landing system capacity” as one of the indicators of system performance efficiency.
UAV navigation using opto-electronic and inertial means in GNSS-denied environment
Authors: Savkin A , Antonov D , Kolganov L , Ryabinkin M , Chekhov E 
Published: June 2021

Abstract
The article presents an approach to improving navigation solution of unmanned aerial vehicle in GNSS-denied environment by means of optoelectronic and inertial measurements. An approach is based on locating and tracking keypoints on the underlying surface to correct inertial system errors. The approach is based on EKF-SLAM and can be applied both in the presence and in the absence of a terrain map. The simulation results of the optical-inertial navigation system readings are presented.
Compressed stiffened composite panels design with skin postbuckling behavior
Authors: Mitrofanov O V , Ryzhova E S 
Published: June 2021

Abstract
The aim of this paper is development of stiffened composite panels design method taking thin skin postbuckling behavior and stringers elastic behavior in case of longitudinal compression into account. Statement of the problem takes geometrically non-linear correlations into account. Variant of rigid boundary conditions is considered for both stiffened panels and skin. Analytic solution of non-linear problem using Ritz method which is reduced to solution of non-linear system of two equations in skin and stringer deflection amplitudes is shown. Obtained analytical solution is used for development of load-bearing panels design method based on postbuckling state. A design method based on thin skin postbuckling state not taking stringers influence into account is shown as an example. In this case following variants of strength criteria are considered: reaching longitudinal normal or tangential transverse critical stress. Besides stiffened composite panels design method taking skin postbuckling behavior in case of stringers elastic behavior into account is shown. With known stringer parameters design task is reduced to solution of non-linear system of two equations in skin thickness and stringer deflection amplitude. In this case stipulation of reaching critical normal stress in the skin is taken as strength criterion.
Molding gate optimization for weld line location away from structures loaded area
Authors: Kurkin E I , Lukyanov O E , Chertykovtseva V O , Espinosa Barcenas O U 
Published: June 2021

Abstract
Weld lines, generated during injection molding, can significantly reduce the mechanical performance of structures. The choosing optimal gate location technique has been developed to set weld lines as far as possible from the region of maximum stresses. A flat product case was considered as an example of a typical aircraft structural element – a pin-joint lug molding from short-fiber reinforced thermoplastic composite material. The Golden-Section search method allowed to solve the optimization problem. Autodesk Moldflow in batch mode controlled by Matlab code through Synergy API was used to solve the direct molding task of determination of the weld line location from gate location dependence. An experiment of the lugs injection molding from several gate positions was carry out to verify the numerical weld line prediction. The solved problem allows choosing the gate position for ensuring the weld lines location away from structures loaded area.
3-D Modelling and prototyping of complex-shaped heterogeneous parts
Authors: Pavlov V , Valkov V 
Published: June 2021

Abstract
This article provides a description and results of a study of the feasibility and applicability of encapsulation of various elements in parts of complex shapes, produced using 3-D printing and 3-D modelling. The relevance of this study is confirmed both by the general high rate of development of 3-D printing technologies in the world, and by the abundance of innovations in the application of these technologies, as well as by the specific features and needs of the specific production of optical sensor prototypes. This article describes the stages of the process and provides examples of encapsulated elements. A set of programs was used to create and modify gCode files in order to carry out the experimental part of the study. Experiments on the encapsulation of fasteners, insulating elements and elements of optical paths were successfully carried out in the course of the study in order to estimate feasibility of these encapsulation techniques. The objectives of the study have been achieved. The results or the research allows us to outline further ways of research, as well as to note the possibility of developing a single software package combining the functions of a slicer and gCode editor.
The reduction of computation load in SBAS system during the polynomial approximation of observations
Authors: Sernov V , Podkorytov A , Isaev Y 
Published: June 2021

Abstract
Processing of the observations from GNSS augmentation system on an example of SBAS system is considered in the study. To compute the corrections the SBAS control center collects and processes enormous amount of data, some of the applied matrix algorithms of estimation of the polynomial coefficients are computationally expensive. Instead of the estimation of the polynomial coefficients with the matrix operations the representation of polynomial value by means of a linear combination of previous observations is suggested in the study. Significant advantage in terms of computation time (up to 250 times) for cycle-slip detection procedure is demonstrated for presented method which is important for aviation because of strict integrity requirements in avia-space sector.
Principles of forming procedures for justifying the economic efficiency of space debris removal processes
Authors: Kaloshina M , Zemlyanskaya A 
Published: June 2021

Abstract
Near-Earth space pollution can be classified as an international problem. The research considers variation technical and technological innovative projects that can decide this problem, as well as methods for calculating the costs of their realization. Cost and labor intensity modeling takes into account the concept of designing systems for the disposal of cataloged space debris. Unitized approaches to technical and economic assessment of the feasibility of space debris disposal concepts are considered and a mechanism for justifying economic efficiency is developed, which includes the following synergistic differentiated principles: the objectivity and subjectivity, the accuracy and reliability increasing, the marginal cost estimation, the probabilistic risk assessment accounting, the principle of logical-probabilistic modeling of development obsolescence in outer space, the principle of risk assessment and monitoring of space projects. The proposed mechanism for evaluating the economic efficiency based on additive factors can be used for economic justification of scientific, technical and experimental-design developments of space vehicles for technological designated purpose.
Test technique for turbine cooled blades of gas turbine engines
Authors: Lepeshkin A , Remchukov S , Yaroslavtsev N , Guanghua Z , Meng Z , Fetisov M , Ilinskaya O , Fedin M , Kuleshov A 
Published: June 2021

Abstract
Test technique for turbine cooled blades of gas turbine engines is developed. The new approaches during development of inductor structures, induction heating devices, cooling systems, hydraulic force loading system and methods for their design to provide the prescribed nonuniform heating the turbine cooled blades and to carry out more effective the thermocyclic tests are presented taking into account the developed test technique. Study of effect of the clearances between inductor and blade surface and change of inductor efficiency on the thermal state of blade is presented. The test rig and improved systems of induction heating and mechanical loading are used to improve accuracy and simulate more complete the operating thermomechanical loading the full-scale cooled and uncooled blades at the thermocyclic tests. The results of rig testing the turbine cooled monocrystalline blades of gas turbine engine are received according to the developed test technique.
Students’ perspectives on 3D-vision
Authors: Krumphals Ingrid , Haagen-Schützenhöfer Claudia , Stradner Lisa 
Published: June 2021

Abstract
The perception of our surroundings is determined by vision to a large extent. Human vision is not only able to generate a three-dimensional impression of three-dimensional objects, but also of two-dimensional objects. Nowadays, 3D-technologies even provide additional opportunities to trigger visual 3D-perception. 3D-vision provides a context for teaching and learning several topics in physics. In order to develop a learning environment for high school students, following the framework of educational reconstruction, students’ perspectives must be considered. As we could not find any documented students’ conceptions on 3D-vision, an exploratory study was conducted. Main aim of this study was to provide a broad overview on students’ perspectives on 3D-vision. Therefore, the questionnaire mainly consisted of open questions. The questionnaire was administered to Austrian secondary level students of two schools and was finally filled in completely by 215 students. Data was analysed by the means of qualitative content analysis and an inductive category system was developed. The results show that students mainly connect 3D-vision with 3D-technologies in cinemas. However, differences between junior and senior high school students were detected. While junior high school students mainly associate 3D-vision with cinemas, senior high school students additionally mention the physiological process of 3D-vision as well as 3D-technology.
Analysis of some selected FCI tasks using eye-tracking
Authors: Krčmářová Anna , Chvátal Roman , Holubová Renata 
Published: June 2021

Abstract
In our contribution, we focus on the analysis of six FCI tasks which were solved by first-year university students. The analysis is conducted using eye-tracking data obtained from the experiment. Some characteristics, like attention maps and sequences of fixations provide a deeper insight into the students’ approaches to the tasks verifying their conceptual understanding to Newtonian mechanics. We can confirm that the students answering correctly were able to find the solution more straightforwardly, making their decision between fewer options. This is also supported by the analysis of fixation numbers and fixation times. The results show differences in the way novices and experts process questions. Moreover, it enables to identify some persistent misconceptions.
Physics education with multimedia applications in non-English teacher-oriented journals: an analysis of 491 articles about multimedia in physics education
Authors: Girwidz R , Thoms L J 
Published: June 2021

Abstract
Journals, intended for teachers, provide practical ideas about the use of multimedia in physics teaching and learning. However, the articles in such journals are usually written in local languages. Here, ten researchers in physics education from different countries provide a review of articles on multimedia applications and corresponding concepts that are discussed in country-specific languages (excluding English). A total of 491 articles about multimedia applications were analysed, using a list of 81 categories. Central topics included teaching strategies, technologies, and multimedia features. Furthermore, differences between countries, changes over time, and notable patterns of articles in 34 teacher-oriented journals from 10 countries are presented.
Current literature offers a broad range of ideas related to the practical use of multimedia. Topics of focus differ between countries and languages, suggesting more international exchange to circulate the best ideas of concrete teaching material for schools across Europe. Furthermore, our findings also suggest a need for improvement in the dissemination of current research findings, as well as a solid theoretical grounding among those who write articles for teacher-oriented journals in local languages.
This article collects and summarizes findings that may be relevant for the international group of scientists and for possible future collaborations.
Using frustrated internal reflection as an analog to quantum tunneling
Authors: Rossum Aernout Van , Berg Ed Van Den 
Published: June 2021

Abstract
Also in teaching quantum physics one would like to bring experiments to the secondary school classroom, if not for “proofing” theories, then at least for illustrating and visualizing concepts. When EM waves are totally internally reflected from the inside of a prism, so called evanescent waves can tunnel through a narrow slit to another prism [1] and the intensity shows the exponential dependence on the width of the slit typical for tunneling. This is an example for quantum tunneling as quantum particles can tunnel as well due to their wave properties. This paper describes our progress from an ineffective microwave tunneling demonstration which we tried out with 5 teachers and 112 students, to a well-known optical demonstration but newly mounted in a small for loan suitcase with an educational script based on our try-outs and the PhET tunneling applet to link quantum concepts to tunneling phenomena.
Teaching quantum physics as a structured physics theory in high school
Authors: Weissman Efraim Yehuda , Merzel Avraham , Katz Nadav , Galili Igal 
Published: June 2021

Abstract
This study presents a new approach to teaching quantum physics in high-school physics courses facing the extremely deficient and fragmented treatment of quantum mechanics at present. The suggested curriculum adopts the paradigm of discipline-culture in representing physics knowledge. In accordance, the curriculum is structured in nucleus-body-periphery emphasizing the principles (nucleus), their illustration (body) and their contrast with the classical postulates (periphery). Thus, the proposed curriculum presents quantum physics as a structured physics theory, unlike most curricula in the world. The results of an experimental application show a positive impact on students’ conceptual knowledge and students’ nature-of-science understanding.
A sequence of experiments and models to grasp the strange nature of light
Authors: Onorato Pasquale , Malgieri Massimiliano , Polesello Marta , Salmoiraghi Alessandro , Oss Stefano 
Published: June 2021

Abstract
We present a sequence of activities designed to stimulate students to reflect on the nature of light and on the different models (ray, wave, classical and quantum particles) used in teaching and learning optics. These activities are also aimed to help students in evaluating the profound meaning of the “correspondence principle” and develop their own views about some aspects of nature of science even if it is not taught explicitly. In fact, optics is a paradigmatic case where different scientific models are proposed in the University (and high school) courses. Even the oldest of these models have non empty domains of validity and both Maxwellian electromagnetism and geometrical optics are largely still used in the Physics curricula. As a consequence students are often puzzled, and think that each of these theories works in a specific domain, without any connection one with the other. Thus we investigate students’ mental models of light in different contexts and we show how they develop hybrid models in explaining different phenomena or use models inconsistently.
Conceptual Test in Wave Optics
Authors: Roskot Michal 
Published: June 2021

Abstract
The presented article deals with the Conceptual Test in Wave Optics. It describes main steps of its development and structure and properties of the final version. Two sets of pilotage testing have been done so far. In the first part of the research 105 high school students were tested with a test reliability described by Cronbach’s alpha on the level 0.2. Due to this low value another testing was carried out, this time with university students. It has showed reliability on the level 0.72. This article deals with results from the analysis of these two data sets and shows examples of possible wave optics misconceptions detected by this testing. The test is attached.
Workshop Demonstrations with almost nothing: Thirty examples with a glass of water
Authors: Berg Ed Van Den 
Published: June 2021

Abstract
Suppose you are suddenly assigned to a bare classroom instead of your nicely equipped physics room. What can you do to still have a clear and exciting lesson? In this workshop I present a collection of small and quick demonstrations and visualizations for secondary education, which require no equipment beyond what is present in a typical lecture room or bare classroom (chalk, chairs, students, books, paper, student bags and typical contents). The nature of the demos is varied, some are to verify an explanation, but most are to illustrate, visualize, or simulate. In the workshop participants will add their own ideas.
The Jumping Ring as an inquiry project: A learning-opportunities perspective
Authors: Langley Dorothy Vivienne , Arieli Rami 
Published: June 2021

Abstract
Incorporating authentic inquiry into high school physics instruction has been advocated for over a century, and has become an integral part of science instruction standards world-wide. The Inquiry Physics program in Israel is a 3 year, elective course for high school physics majors. Students acquire scientific research knowledge and skills primarily by performing inquiry projects of increasing complexity and finally devoting a full year to researching a significant issue under the guidance of expert mentors. Selecting a suitable research topic requires management of tensions related to complexity of content, experimental practice, data analysis and project logistics. The Jumping Ring phenomenon, in which a metal ring is launched vertically due to a magnetic force generated by a coil carrying AC current, was the subject of a final inquiry project in 2018. The phenomenon offers dramatic appeal and motivation, rich inquiry options and diverse experimental skills, considerable knowledge consolidation and extension (magnetic fields and forces, electromagnetic induction and AC circuits) along with technological and logistic manageability. Mentoring the project involved exploring an uncharted learning-opportunities’ path, balancing direct instruction and independent exploration, as well as dealing with time constraints and variations in the project team’s attendance and commitment.