bluuebunny/crossref_metadata_2025 huggingface dataset:
High-resolution He I 10830 Å Narrowband Imaging for a Small-scale Chromospheric Jet
Authors: Wang Ya , Zhang Qingmin , Ji Haisheng
Published: May 2021

Solar jets are ubiquitous phenomena in the solar atmosphere. They are important in mass and energy transport to the upper atmosphere and interplanetary space. Here, we report a detailed analysis of a small-scale chromospheric jet with high-resolution He i 10830 Å and TiO 7057 Å images observed by the 1.6 m aperture Goode Solar Telescope at the Big Bear Solar Observatory. The observation reveals the finest dark threads inside the jet are rooted in the intergranular lanes. Their width is equal to the telescope’s diffraction limit at 10830 Å (∼100 km). The jet is recurrent and its association with the emergence and convergence of magnetic flux is observed. Together with other important features like photospheric flow toward the magnetic polarity inversion line, a bald-patch magnetic configuration, and earlier excitation of helium atoms, we propose that the jet might be initiated by magnetic reconnection in a U-shaped loop configuration. The plasmoid configuration results from the possible buoyancy of the magnetic reconnection, which reoccurs in a second step with an overlying magnetic field line. Notably, the second-step magnetic reconnection produces not only bidirectional cool or hot flows but also a new U-shaped loop configuration. The feature may be used to explain the recurrent behavior of the jet, since the new U-shaped loop can be driven to reconnect again.
The JCMT BISTRO-2 Survey: The Magnetic Field in the Center of the Rosette Molecular Cloud
Authors: Könyves Vera , Ward-Thompson Derek , Pattle Kate , Di Francesco James , Arzoumanian Doris , Chen Zhiwei , Diep Pham Ngoc , Eswaraiah Chakali , Fanciullo Lapo , Furuya Ray S. , Hoang Thiem , Hull Charles L. H. , Hwang Jihye , Johnstone Doug , Kang Ji-hyun , Karoly Janik , Kirchschlager Florian , Kirk Jason M. , Koch Patrick M. , Kwon Jungmi , Lee Chang Won , Onaka Takashi , Robitaille Jean-François , Soam Archana , Tahani Mehrnoosh , Tang Xindi , Tamura Motohide , Berry David , Bastien Pierre , Ching Tao-Chung , Coudé Simon , Kwon Woojin , Wang Jia-Wei , Hasegawa Tetsuo , Lai Shih-Ping , Qiu Keping
Published: May 2021

We present the first 850 μm polarization observations in the most active star-forming site of the Rosette Molecular Cloud (d ∼ 1.6 kpc) in the wall of the Rosette Nebula, imaged with the SCUBA-2/POL-2 instruments of the James Clerk Maxwell telescope, as part of the B-Fields In Star-forming Region Observations 2 (BISTRO-2) survey. From the POL-2 data we find that the polarization fraction decreases with the 850 μm continuum intensity with α = 0.49 ± 0.08 in the p ∝ I
−α
relation, which suggests that some fraction of the dust grains remain aligned at high densities. The north of our 850 μm image reveals a “gemstone ring” morphology, which is a ∼1 pc diameter ring-like structure with extended emission in the “head” to the southwest. We hypothesize that it might have been blown by feedback in its interior, while the B-field is parallel to its circumference in most places. In the south of our SCUBA-2 field the clumps are apparently connected with filaments that follow infrared dark clouds. Here, the POL-2 magnetic field orientations appear bimodal with respect to the large-scale Planck field. The mass of our effective mapped area is ∼174 M
⊙, which we calculate from 850 μm flux densities. We compare our results with masses from large-scale emission-subtracted Herschel 250 μm data and find agreement within 30%. We estimate the plane-of-sky B-field strength in one typical subregion using the Davis–Chandrasekhar–Fermi technique and find 80 ± 30 μG toward a clump and its outskirts. The estimated mass-to-flux ratio of λ = 2.3 ± 1.0 suggests that the B-field is not sufficiently strong to prevent gravitational collapse in this subregion.
Multispacecraft Observations of Coronal Loops to Verify a Force-free Field Reconstruction and Infer Loop Cross Sections
Authors: McCarthy Marika I. , Longcope Dana W. , Malanushenko Anna
Published: May 2021

Active region EUV loops are believed to trace a subset of magnetic field lines through the corona. Malanushenko et al. proposed a method, using loop images and line-of-sight photospheric magnetograms, to infer the 3D shape and field strength along each loop. McCarthy et al. used this novel method to compute the total magnetic flux interconnecting a pair of active regions observed by SDO/AIA. They adopted the common assumption that each loop had a circular cross section. The accuracy of inferred shape and circularity of cross sections can both be tested using observations of the same loops from additional vantage points as provided by STEREO/EUVI. Here we use multiple viewing angles to confirm the 3D structure of loops. Of 151 viable cases, 105 (69.5%) matched some form of visible coronal structure when viewed approximately in quadrature. A loop with a circular cross section should appear of a similar width in different perspectives. In contradiction to this, we find a puzzling lack of correlation between loop diameters seen from different perspectives, even an anticorrelation in some cases. Features identified as monolithic loops in AIA may, in fact, be more complex density enhancements. The 30.5% of reconstructions from AIA that did not match any feature in EUVI might be such enhancements. Others may be genuine loop structures, but with elliptical cross sections. We observe an anticorrelation between diameter and brightness, lending support to the latter hypothesis. Of 13 loops suitable for width analysis, 4 are consistent with noncircular cross sections, where we find anticorrelation in both comparisons.
Solar Origin of Compressive Alfvénic Spikes/Kinks as Observed by Parker Solar Probe
Authors: He Jiansen , Zhu Xingyu , Yang Liping , Hou Chuanpeng , Duan Die , Zhang Lei , Wang Ying
Published: May 2021

The solar wind is found by the Parker Solar Probe to be abundant with Alfvénic velocity spikes and magnetic field kinks. Temperature enhancement is another remarkable feature associated with the Alfvénic spikes. How the prototype of these coincident phenomena is generated intermittently in the source region is an important and wide-ranging subject. Here we propose a new model introducing guide-field discontinuity into the interchange magnetic reconnection between open funnels and closed loops with different magnetic helicities. The modified interchange reconnection model not only can accelerate jet flows from the newly opening closed loop but also can excite and launch Alfvénic wave pulses along the newly reconnected and post-reconnected open flux tubes. We find that the modeling results can reproduce the following observational features: (1) Alfvén disturbance is pulsive in time and asymmetric in space; (2) Alfvénic pulse is compressive with temperature enhancement and density variation inside the pulse. We point out that three physical processes co-happening with Alfvén wave propagation can be responsible for the temperature enhancement: (a) convection of heated jet flow plasmas (decrease in density), (b) propagation of compressive slow-mode waves (increase in density), and (c) conduction of heat flux (weak change in density). We also suggest that the radial nonlinear evolution of the Alfvénic pulses should be taken into account to explain the formation of magnetic switchback geometry.
Improved Constraints for the XUV Luminosity Evolution of Trappist-1
Authors: Birky Jessica , Barnes Rory , Fleming David P.
Published: May 2021

We re-examine the XUV luminosity evolution of TRAPPIST-1 utilizing new observational constraints (XUV and bolometric luminosity) from multi-epoch X-ray/UV photometry. Following the formalism presented in Fleming et al., we infer that TRAPPIST-1 maintained a saturated XUV luminosity, relative to the bolometric luminosity, of log10(L
XUV/L
bol)

=
−

3.03

−
0.23

+
0.25

at early times for a period of t
sat

=

3.14

−
1.46

+
2.22

Gyr. After the saturation phase, we find L
XUV decayed over time by an exponential rate of β
XUV

=
−

1.17

−
0.28

+
0.27

. Compared to our inferred age of the system,

age
=

7.96

−
1.87

+
1.78

Gyr, our result for t
sat suggests that there is only a ∼4% chance that TRAPPIST-1 still remains in the saturated phase today, which is significantly lower than the previous estimate of 40%. Despite this reduction in t
sat, our results remain consistent in the conclusion that the TRAPPIST-1 planets likely received an extreme amount XUV energy—an estimated integrated XUV energy of ∼1030–1032 erg over the star’s lifetime.
« Comme des enfants avec un jeu de lego »
Authors: Roumanos Rayya , Strick Benjamin
Published: May 2021

Quelles sont les marques d’une bonne enquête OSINT ? Pour Benjamin S Strick , membre du collectif Bellingcat et collaborateur régulier de la cellule Africa Eye de la BBC, la curiosité, l’esprit critique et le travail collaboratif sont les trois ingrédients indispensables d’une recette qui change au gré des enquêtes et des cellules d’investigation.
Les promesses et les défis journalistiques de l’ Open Source Intelligence (OSINT)
Authors: Roumanos Rayya
Published: May 2021

Appliquées de plus en plus souvent dans les rédactions, les techniques issues de l’ Open Source Intelligence (OSINT) ouvrent de nouvelles perspectives en matière d’investigation. Des révélations, en 2014, sur le crash du vol MH17 au-dessus de l’Ukraine à l’identification, en 2021, des assaillants du Capitole, elles constituent une aide précieuse pour mener à bien des enquêtes nourries quasi exclusivement par des ressources disponibles librement sur Internet.
La communauté de pratiques Open Source Intelligence (OSINT) : un réseau qui se consolide
Authors: Le Deuff Olivier , Roumanos Rayya
Published: May 2021

L’existence d’une communauté OSINT s’observe par le développement de lieux d’échanges et de projets dédiés. Au-delà des différences évidentes, un esprit commun se dessine autour de certaines pratiques, méthodes et valeurs qui reposent sur des logiques collaboratives et humanitaires.
Une représentation sous contrôle : visions du système politique et réformes institutionnelles dans le mouvement des Gilets jaunes
Authors: Bedock Camille , Bonin Loïc , Liochon Pauline , Schnatterer Tinette
Published: May 2021

La mobilisation des Gilets jaunes, diverse et protéiforme, s’est caractérisée par des discours et des revendications institutionnelles et démocratiques. À partir d’une base de données de questionnaires recueillis in situ et d’entretiens approfondis, cet article s’intéresse aux visions du système politique et aux réformes revendiquées par les Gilets jaunes. L’article montre que malgré l’existence de critiques très fortes des organisations politiques instituées ou élues et la conviction d’évoluer dans un système non démocratique, les Gilets jaunes ne revendiquent pas une sortie de la représentation politique, mais sa refondation autour de trois principes : le contrôle des élu·es notamment par la démocratie directe, l’écoute, et la proximité statutaire et géographique des élu·es.
Gamification Design Elements to Enhance Adolescent Motivation in Diagnosing Depression
Authors: Jamaludin Nurul Fasihah , Tengku Wook Tengku Siti Meriam , Mat Noor Siti Fadzilah , Qamar Faizan
Published: May 2021

Depression is a critical public health problem, mainly when it affects young people (adolescents). This condition is most challenging to detect in this group because they tend to think about other people's negative assumptions. Adolescents with depressive symptoms refuse to seek professional help due to their stigma and their future if they were labeled as depressed teenagers. Depression is a severe mental issue that should be detected from an early stage so that the problem can be curbed and resolved immediately. Diagnosis should be carried out to assess mental health, followed by referral to professional help. This study aims to motivate adolescents to diagnose depression levels through gamification techniques. Fifty-three secondary students participated in a survey designed in this study to measure motivation enhancement factors. The result of this study was used to develop a depression diagnosis model. The proposed model applied a gamification design technique consisting of three main ideas: gamification elements, user types, and motivational elements. This model will serve as the foundation to develop a mobile application system that can benefit users, especially adolescents, in self-diagnosing depression.
AI for Facial Autobiographical Memory Recovering and Transmission. A Study for a Mobile and Web Application
Authors: Soro Elsa , Barbotto Silvia , Gramigna Remo , Santangelo Antonio Dante , Voto Cristina , Leone Massimo
Published: May 2021

Drawing on research conducted within the ERC Consolidator Project FACETS, this presentation aims at describing the state of art of solutions currently offered by AI for coping with loss of memory and identity in the pandemic scenario and at discussing advantages and disadvantages of these digital tools. On the one side, the presentation will focus on how the interpersonal physical distance imposed because of the risk of contagion might be dealt with by applications based on Artificial Intelligence purposed to mitigate the loss of memory in elderly people by building new bridges between them and the generation of digital natives. On the other side, the paper will concentrate on obstacles that hamper the adoption of Artificial Intelligence across the generations. Lack in digital literacy as well as inappropriate interaction design as obstacles to effective cooperation between humans and artificial intelligence will be particularly stressed.Finally, the presentation aims at presenting a concept study for a mobile and web application for autobiographical memory recovering, digitalization, preservation, recreation and transmission. The app is intended to bear on the visage as a memory and identity catalyst so as to enhance the neurophysiological functions of users, training their memory, and improving their ability to communicate.
A Business Merger and Acquisition Knowledge Management System Using Artificial Intelligence Techniques
Authors: Pal Kamalendu
Published: May 2021

Knowledge is recognized as a strategic resource, with major key drivers being the need to cut time to market and gain the business opportunities in a global market with new products and services. This chapter presents a knowledge management system known as guidance for business merger and acquisition (GBMA) process. This application uses a hybrid knowledge-based system to place bidding on the target company, formulating a strategy, and modification of the initial strategy if necessary, for the business acquisition processes. Legal knowledge for GBMA is represented in two forms, as rules and cases. Besides distinguishing the two different forms of knowledge representation, the chapter outlines the actual use of these forms in a computational architecture that is designed to generate a suitable solution, for a given new business scenario, using different reasoning mechanisms (e.g., rule-based reasoning, case-based reasoning). Business scenarios are used to show the functionalities of the presented architecture.
Knowledge Management in Human-Robot Interaction Approaches and Processes
Authors: Brown-Acquaye William Leslie , Yeboah-Boateng Ezer Osei , Lempogo Forgor
Published: May 2021

Cognitive robots, exhibiting cognitive characteristics and synthesizing knowledge to perform tasks and interacting with humans in both industrial and social settings, have become a big part of modern societies. In this chapter, the authors review the processes and approaches to knowledge management in cognitive robot agents for effective human robot interaction. They present the current state of the art in current robotics technology and human-robot interaction. They state current requirements of cognitive robot agents in human-robot interaction and examine the role of knowledge in human-robot interaction. They finally propose a knowledge management framework for cognitive robots that consist of three main stages: knowledge acquisition and grounding, knowledge representation and knowledge integration, and instantiation into robot architectures.
Big Data Analytics in Developing Economies
Authors: Lempogo Forgor , Yeboah-Boateng Ezer Osei , Brown-Acquaye William Leslie
Published: May 2021

In a world increasingly driven by data, most developed economies are leveraging big data to achieve greater feats in various sectors of their economies. From advertisement, commerce, healthcare, and energy to defense, big data has given new insights into the huge volume of data accumulated over the past few decades that is helping reshape our knowledge and understanding of these sectors. Unfortunately, the same cannot be said about the state of big data in the developing world, where investments in IT infrastructure are dangerously low, keeping huge proportions of the population offline. This chapter discussed the challenges that exist in developing countries, which affect the smooth take-off of big data and data science as well as recommendations as to how countries and companies in the developing world can overcome these challenges to harness the benefits and opportunities presented by this technology.
An Assessment of the Quality of Data From the EPI for Knowledge Management in Healthcare in Ghana
Authors: Gyaase Patrick Ohemeng , Boye-Doe Joseph Tei , Okantey Christiana
Published: May 2021

Quality data from the Expanded Immunization Programme (EPI), which is pivotal in reducing infant mortalities globally, is critical for knowledge management on the EPI. This chapter assesses the quality of data from the EPI for the six childhood killer diseases from the EPI tally books, monthly reports, and the District Health Information Management System (DHIMS II) using the Data Quality Self-Assessment (DQS) tool of WHO. The study found high availability and completeness of data in the EPI tally books and the monthly EPI reports. The accuracy and currency of data on all antigens from EPI tally books compared to reported number issued were comparatively low. The composite quality index of the data from the EPI is thus low, an indication poor supervision of the EPI programme in the health facilities. There is therefore, the need for effective monitoring and data validation at the point of collection and entry to improve the data quality for knowledge management on the EPI programme.
Redox Behavior of Chelate Complexes Based on 8-Oxyquinoline Promising in OLED Display Technology
Authors: Arutyunyants A.A. , Salamova N.A.
Published: May 2021

The electrochemical behavior of 8-oxyquinoline and chelate complexes based on it (Sn (Oxin)Cl3, Ge (Oxin)Cl3, Ti (Oxin)Cl3, W(Oxin)2Cl4, Fe (Oxin)Br, Sb (Oxin)Cl2, Sb (Oxin)Cl4, Sn (Oxin)2Cl2, Ti (Oxin)2Cl2 have been studied by cyclic voltammetry in aprotic solvents in a three-electrode system on platinum and glass-graphite disk electrodes. It has been shown that in the case of metal oxyquinolinates, the ligand is 8-oxyquinoline reducing in two one-electron diffusion waves. The first wave is observed at less negative potentials than the first quinoline one, while the second waves have almost the same potentials. The first wave is related to the OH- proton discharge.
The complexes under study are electrolytically oxidizable. A single two-electron peak is observed in the cyclic voltammogram in the anodic region for the Ti (Oxin)Cl3 chelate complex. This is probably associated with two irreversible sequential or parallel stages with close oxidation potentials. By analogy to the processes considered for 8-oxyquinoline, the rupture of the oxygen-metal bond is observed at the first stage. The resulting radical cation is unstable and decomposes into a radical and a cation with a positive charge in the titanium atom. Electrolytic oxidation of complexes Fe (Oxin)Br, Sb (Oxin)Cl2, Sb (Oxin)Cl4, and Sn (Oxin)2Cl2 is similar to that of Ti (Oxin)Cl3.
Optimization of the Choice of Technological Methods for Nanomodification of Natural Aluminosilicates through the Parameters of the Element-Oxygen Chemical Bond
Authors: Sirotkin O.S. , Buntin Artem E.
Published: May 2021

The paper shows the possibility of using such quantitative characteristics of the element-oxygen chemical bond as the covalent character, metallic character and ionic character in substances to select a set of technological methods and develop a technology for nanomodification of natural bentonite aluminosilicates. The research results showed that thermal activation of bentonite at 200, 300, 380 and 400 °C with different modes of isothermal exposure (15, 30, 60, 120 minutes) does not significantly affect the efficiency of its modification with silicon (SS) and aluminum (AS) oxide nanoparticles, estimated by the increment of the compressive strength and the adsorption index for methylene blue. Obtaining a 46 % aqueous suspension of bentonite and modifying it with silicon and aluminum oxide nanoparticles followed by ultrasonic treatment after standing decreases the particle size by more than 4 times, which is a promising technological solution for improving the performance properties of ceramics, molding mixtures, adsorbents and other materials based on bentonite from various deposits.
Elasticity Modulus and Hardness of Bearing Steel after Laser Treatment
Authors: Morozov V. , Gusev V.G. , Gavrilov D.
Published: May 2021

The article considers the effect of laser treatment of bearing steel on the change in the elasticity modulus and hardness of the steel SHH15SG. Multi-factor models were obtained that relate the output parameters to the power W of laser radiation, the longitudinal feed Spr of the laser beam and the distance L from the protective glass of the focusing head to the workpiece surface. According to the degree of reduction of the influence on the elastic modulus of steel SHH15SG subjected to laser treatment, these factors are arranged in a sequence: W, Spr, and L. With increasing W and L the modulus of elasticity and hardness of the treated surface layer increase. 3M-XYZ surface-graphs, 3M-XYZ contour-graphs of interactive influence of independent factors on the elastic modulus and hardness of the surface layer are constructed, which simplifies the procedure for assigning the processing mode. The research results are useful for manufacturing and design companies that implement laser technologies and create laser equipment.
Features of the Structure of the Material Formed from AK4-1 Powder Using Laser Energy
Authors: Kulchin Yuri N. , Nikiforov Pavel A. , Pivovarov D.S. , Yatsko D.S. , Timchenko V.A.
Published: May 2021

The paper presents the results of studying the microstructure of samples obtained with laser processing of AK4-1 aluminum alloy powder. It has been found that increasing the initial temperature of the substrate to 100...150 °C allows to use this powder material in directed energy deposition (DED) additive process to create stiffening elements on the surface of thin-walled aluminum parts. When the specified temperature condition is satisfied, the crystallization rate decreases, allowing to obtain samples with almost no internal cracks. The results of comparing the microstructure and the microhardness of commercial AK4-1 wrought alloy and the samples obtained with DED process are presented. The structure of the samples prepared with laser cladding is more disperse in comparison with wrought alloy. The microhardness of the sample prepared at pre-heated substrate is comparable with wrought alloy. The conceptual architecture of the decision support software for laser powder cladding processes is presented. Its information and software components are briefly described.
Features of the Formation of Structure and Geometry during Direct Laser Deposition of 321L Stainless Steel on Complex Groove Using the LENS Method
Authors: Bobyr Vitaly , Kuznetsov P. , Zhukov A. , Shakirov I.
Published: May 2021

Additive manufacturing is a new approach to solving the problems of creating high-performance instrument components. This article is devoted to the solution of the narrowly directed problem of surfacing metal powder 321L using the LENS method on the solenoid valve core. The core is made of electrical steel, in which a complex groove is machined. The difficulty of this work was to accurately perform the geometry of the melt layer that is not standard for this method. As a result, the product was obtained according to a completely new approach to its design, which subsequently gave increased operational characteristics of the final product. The article presents the problems that can be encountered when performing complex crevice surfacing on a complex groove. The structure of the deposited layer is considered, defects characteristic of this method in the form of interlayer pores, unalloyed powder particles are identified and described. The LENS process control modes are presented in order to reduce defects and improve the development of surfacing geometry.
Features of Glass Plate Hardening by the Ion Exchange Method
Authors: Petrov D. , Bragina L. , Demydchuk L.
Published: May 2021

In this work various methods of glass plate hardening are considered. These plates are used to protect defense devices. As a glass was used system R2O-B2O3-SiO2. The method of thermal hardening was considered. Technological disadvantages of this method were discovered by analyzing Newton's rings and a polarizing plate. The use of chemical hardening has shown its advantages over the thermal method. The essence of the method is the ion exchange of alkali metals between glass plates and the chemical mixture melt. The operating principle of the chemical hardening equipment and its technology were considered. As a result, hardened glass plates with preservation of planar geometry were obtained.
Precast Textured Tool and the Construction of an Intensive Grinding Process Based on It
Authors: Gusev V.G.
Published: May 2021

The article deals with the construction of an intensive process of grinding materials using a precast textured wheel and a device for the centrifugal giving of lubricating and cooling liquid (LCL) directly to the local contact zones of the cutting and pressing abrasive grains with the processed material. The design of the tool and an effective method of coolant giving to the cutting zone are described, which provide the required roughness of the treated surface and eliminate structural changes in the surface layer under intensive grinding conditions. An increase in the rate of heat removal from the grinding zone is achieved by using a textured tool design, a device for centrifugal giving of coolant and accelerating the liquid to approximately the cutting speed. A method for constructing an intensive grinding process with a precast textured tool has been developed, the implementation of which can significantly increase the processing efficiency. The results of the research are recommended for grinding steels, cast iron and other metals and alloys that are prone to the formation of cauterization, tensile residual stresses and other thermal defects that occur under the influence of high temperature in the grinding zone.
On the Durability of Concrete under the Action of Ultra-Low (up to -196 °C) Technological Temperatures
Authors: Yarmakovsky V.N. , Kadiev D.
Published: May 2021

The article presents the physical-chemical bases and as result – the technological bases of concrete resistance to ultra-low cryogenic (up to-196 °C) technical (engineering) temperatures, which is applied to the reinforced concrete structures of engineering constructions such as storage tanks for liquefied gases (in particular, liquid nitrogen and oxygen with cryogenic temperatures), as well as the enclosing structures of blocks (units) for air separation for various inert gases. The above-mentioned physical and chemical bases of concrete resistance to the ultralow cryogenic technical temperatures are developed, using the results of the analysis of modern ideas (hypotheses and theories) about the mechanism of low negative temperatures exposure on structural lightweight aggregate concrete and normal weight concrete due to the characteristics of their macro-and microstructure. The resistance of structural lightweight aggregate concrete in comparison with equal-strength normal weight concrete to the cyclic exposure of cryogenic temperatures was performed by the authors based on the results of the relevant analytical and experimental investigations. The results of these investigations are considered in the article as a modern scientific basis for the development of the main provisions for the manufacturing technology of structural lightweight aggregate concrete and normal weight concrete with high durability (frost resistance and water resistance) in conditions of cyclic exposure to cryogenic temperatures. The results of changes in strength and deformative characteristics of concrete in the process of cyclic freezing and thawing are accepted as evaluation criteria of the resistance of concrete, manufactured using the above-mentioned technologies, to such temperature exposure.
Effective Fine Concrete Modified with a Highly Dispersed Wollastonite-Based Additive
Authors: Karpikov E.G. , Lukuttsova N.P. , Blagoder T.P. , Bondarenko E.A.
Published: May 2021

An effective highly dispersed additive based on the wollastonite Miwoll 05-97 with an average particle diameter of 6.5 microns is obtained. A stable effect of interacting the additive components with Portland slag cement CEM II/A–Ш 42.5H is revealed; it results in improving the strength of fine-grained concrete produced with the raw materials mentioned above. It is established that using water suspension of wollastonite solid particles, highly water-reducing/superplasticizing modifier based on the polycarboxylate ether Master Glenium 430, as a stabilizer of the surface-active substance allows producing an additive with an evener distribution of solid particles in the liquid, and with stable functional properties. A highly dispersed wollastonite-based additive, obtained by ultrasonic dispersion for 10 minutes in the bath-type activator at the frequency of 35 kHz in the aquatic environment with a suspension stabilizer, enables producing the wollastonite-modified fine concrete with a compressive strength of more than 50 MPa, with the 10% additive being 2 times higher than that of the control.
Modified Gypsum Binder for Plastering Systems
Authors: Asamatdinov M.O. , Popov I.I. , Chernukhin S.P. , Zhukov Alexey D.
Published: May 2021

A natural gypsum binder or its analogs, which are the products of local raw materials recycling or by-products of other industries, is used as a basic component in the composition of interior plastering mixtures. Plaster coatings based on a gypsum binder have two main features. The first is the ability to control room humidity and absorb harmful emissions. The second is the ability to implement the barrier protection function in case of fire.Improvement of plastering works quality and optimization of their cost is related to the development of modified gypsum-based compositions, the justified use of waste, and local building materials, which include a clay-gypsum binder. Clay gypsum as a natural material of sedimentary origin is widespread both in Russia and in post-Soviet countries. In terms of energy intensity and manufacturability, raw materials recycling into clay-gypsum binder does not differ from the conditions of traditional processing of natural gypsum. Compared with lime or cement mortars, mortars based on clay-gypsum binders have greater elasticity and plasticity. Such properties as convenient masonry and thixotropy as well as the interval for maintaining the viability of the mixture are related to application technology and regulated by the insertion of modifying additives, which formulation was the aim of the research. The research results are presented in this article. Studies have shown that varying the recipe parameters allows us to control both the strength and operating characteristics of clay-based mixtures, as well as their application technology.
The Influence of Ferrous Metallurgy Waste in the Aktobe Region on the Frost Resistance of Ceramic Bricks Based on Low-Melting Clay
Authors: Kairakbaev A.K. , Abdrakhimova E. S. , Abdrakhimov V.Z.
Published: May 2021

The research objective is studying the effect of tailing slurry of chromite ore beneficiation on the phase composition and frost resistance of ceramic bricks obtained based on low-melting clay. For the study, two compositions were taken, % wt.: 1) the optimal composition ─ low-melting clay of the Ilek deposit - 70, tailing slurry of chromite ore beneficiation, 2) the reference composition ─ low-melting clay of the Ilek deposit - 100. Raw materials were crushed to pass through a sieve No. 1.0 mm; then, the components were thoroughly mixed. The bricks were prepared by melting at a batch moisture content of 22 %. The mold bricks were dried to a residual moisture content of 5 % max. The dried bricks were fired at temperatures, оС: 950 (the glass phase emergence), and 1,050 (the final brick firing temperature). The increased content of iron oxide (Fe2O3=12.3 %) and alkali oxides (R2O=3.2 %) in the tailing slurry of chromite ore beneficiation contributed to the liquid phase emergence at 950 оС. Colorless, yellowish, and brown glasses with refractive indices N within 1.50-1.54, forming as a result of melting of spars and mixed-layer clayey formations, were observed under the microscope in the studied prototypes of composition No. 1 at a firing temperature of 950 °C. In the composition No. 2, a liquid phase also emerges, but in smaller quantities.
Adding tailing slurry of chromite ore beneficiation to ceramic masses contributes to the formation of anorthite and glass phase in prototypes based on low-melting clay at a firing temperature of 950 °C. An increase in the firing temperature to 1,050 °C increases the content of the glass phase and anorthite, which significantly improves the frost resistance of ceramic bricks.
Filled Heat Efficient Ceramics
Authors: Zhukov Alexey D. , Popov I.I. , Bessonov Igor V. , Chernukhin S.P.
Published: May 2021

The increase of thermo-physical properties of masonry made of ceramic burnt products is possible through the use of heat-efficient ceramics and, in particular, porous building tiles. The use of combustible additives or foaming technology is related to increased energy costs and difficulties in obtaining products with uniformly distributed porosity.The analysis of the state of the technology of ceramic materials made it possible to formulate a research hypothesis according to which the use of a porous non-combustible additive in the composition of ceramic masses, on the one hand, will make it possible to obtain materials with a lower density compared to traditional ceramic products, and, on the other hand, will allow the use of hard mixtures with reduced water content, and therefore significantly save the cost of drying products, while increasing the uniformity of the porous ceramic crock.The purpose of the research was to develop recipes for ceramic porous products and to develop modes of their burning. The use of crushed foam glass as a lightweight non-burning and exhausting additive, on the one hand, made it possible to use tough ceramic mixtures (with a water content not exceeding 18%), and, on the other hand, to use more rigid and shorter drying modes, which also reduced the energy and material consumption of the technology.The most energy-intensive burning process was optimized by the methods of mathematical planning and processing of experimental results. The average density of crushed foam glass (140–150 kg/m3), optimal for the burnt product, was established, and also, as a result of analytical optimization and interpretation of the experimental results, dependencies that allow choosing parameters and evaluating product properties depending on foam glass consumption and burning temperature were obtained.
Relieving of Residual Stresses in Metal Workpieces at High and Low Temperatures
Authors: Polonik Marina V.
Published: May 2021

On the basis of previously accumulated irreversible deformations, and, consequently, residual stresses, the process of removing residual stresses in metal workpieces under the action of low and high temperatures is simulated. Boundary value problems are solved and here are described regularities that are responsible for removing residual stresses for processing modes: high-temperature heating - cooling, high-temperature heating - holding - cooling, low-temperature heating - holding - cooling. The holding stage is modeled, taking into account the creep properties of materials under Norton creep conditions. According to the dependences of the obtained exact solutions, it is shown that it is the holding process that leads to the relaxation of residual stresses.
Designing of Thin Composite Panels with the Post-Buckling Behavior Considering Rigid Support and Loading with Shear Flows
Authors: Mitrofanov O. , Mazen O.
Published: May 2021

Geometrically non-linear problem of orthotropic thin rectangular panel post-buckling behavior with shear is solved. Deflection function takes all-boundary rigid support conditions into account. Based on derived solution method of smooth panels design which can be used for aircraft structures rib and spar webs optimal parameters is suggested.
Seismic Resistance of Nonlinearly Deformable Large-Span Spatial Structures, Taking into Account Changing Dynamic Stiffness
Authors: Razzakov S.R.
Published: May 2021

Elaboration analytical and computer modeling, changing dynamic parameters of short-term and long-term loaded nonlinearly deformable large-span spatial shell structures are investigated in this research paper. The proposed physical and geometrically nonlinear models of deformation and computational algorithms for solving dynamic problems are applied to assess the stress-strain state of smooth and ribbed spatial systems with variable stiffness caused by the accumulation of damage and the orthotropic structure reinforced by the ribs of the structures of the studied systems. The possibility of using the proposed method of accounting for variable dynamic stiffnesses in calculations for solving problems of dynamic strength and stability of spatial large-span shells of complex geometry is shown.
Behavior of Polygonal Shells of Complex Geometry, Taking into Account the History of a High Level of Loading
Authors: Razzokov J.S.
Published: May 2021

The paper presents the results of the study of the stress-strain state of polygonal shells of positive and negative curvature with different geometric shape of the plan, taking into account the influence of the prehistory of a high loading level. To derive the resolving equation, equation, a mixed-type equation of the moment theory of shells was used. The calculation of the investigated out according to the moment theory, taking into account the influence of a complex stress state edge effect. The numerical implementation of this solution is carried out in relation to hinged and restrained shells. The bearing capacity of short-term and long-term loaded reinforced concrete polygonal shells was investigated by the method of limiting equilibrium.
Navigating in Deep Waters: How Tissue Damage and Inflammation Shape Effector and Memory CD8+ T Cell Responses
Authors: Borges da Silva Henrique
Published: May 2021

Memory CD8+ T cells promote protective immunity against viruses or cancer. Our field has done a terrific job identifying how CD8+ T cell memory forms in response to Ag. However, many studies focused on systems in which inflammation recedes over time. These situations, while relevant, do not cover all situations in which CD8+ T cell memory is relevant. It is increasingly clear that CD8+ T cells with a memory phenotype form in response to infections with extensive or prolonged tissue inflammation, for example, influenza, herpes, and more recently, COVID-19. In these circumstances, inflammatory mediators expectedly affect forming memory CD8+ T cells, especially in tissues in which pathogens establish. Notwithstanding recent important discoveries, many outstanding questions on how inflammation shapes CD8+ T cell memory remain unanswered. We will discuss, in this review, what is already known and the next steps to understand how inflammation influences CD8+ T cell memory.
Sheaf representations and locality of Riesz spaces with order unit
Authors: Di Nola Antonio , Lenzi Giacomo , Spada Luca
Published: May 2021

We present an algebraic study of Riesz spaces (=real vector lattices) with a (strong) order unit.  We exploit a categorical equivalence between those structures and a variety of algebras called RMV-algebras.  We prove two different sheaf representations for Riesz spaces with order unit: the first represents them as sheaves of linearly ordered Riesz spaces over a spectral space, the second represent them as sheaves of "local" Riesz spaces over a compact Hausdorff space.  Motivated by the latter representation we study the class of local RMV-algebras.  We study the algebraic properties of local RMV-algebra and provide a characterisation of them as special retracts of the real interval [0,1]. Finally, we prove that the category of local RMV-algebras is equivalent to the category of all Riesz spaces.
Bihomogeneous symmetric functions
Authors: Billig Yuly
Published: May 2021

We consider two natural gradings on the space of symmetric functions: by degree and by length. We introduce a differential operatorTthat leaves the components of this double grading invariant and exhibit a basis of bihomogeneous symmetric functions in which this operator is triangular. This allows us to compute the eigenvalues ofT, which turn out to be nonnegative integers.
Spontaneous silent sinus syndrome (imploding antrum syndrome): case series of 16 patients
Authors: Babar-Craig H. , Kayhanian H. , De Silva D.J. , Rose G.E. , Lund V.J.
Published: May 2021

INTRODUCTION: Silent sinus syndrome (SSS) is a rare idiopathic collapse of the maxillary sinus and orbital floor. We present the second largest series of sixteen patients with SSS and describe their management. METHODS: A cohort of 16 patients with spontaneous SSS between 1999 and 2009 were reviewed at the Royal National Throat Nose and Ear Hospital. All patients were initially referred from a postgraduate ophthalmic hospital, Moorfields Hospital. RESULTS: Fourteen patients required endoscopic sinus surgery to re-establish maxillary sinus drainage and the remaining two settled with intranasal medical therapy consisting of steroids and decongestions. Follow- up ranged from 6 months to 4 years with a mean of 2.6 years. An improvement in enophthalmos and was seen in all surgically treated patients with a mean improvement of 2.2mm and range 0.5-4mm. DISCUSSION: SSS arises from congestion of the ostiomeatal complex resulting in negative pressure within the maxillary sinus and a gradual implosion of the antral cavity. Endoscopic sinus surgery successfully re-establishes maxillary aeration in our series and leads to clinical and aesthetic improvement in the degree of enophthalmos and has avoided the need for orbital floor repair in all but two cases.
Optical and electromagnetic tracking for navigated surgery of the sinuses and frontal skull base
Authors: Kral F. , Puschban E.J. , Reichelmann H. , Pedross F. , Freysinger W.
Published: May 2021

BACKGROUND: New hardware and software algorithms in electromagnetic tracking for computer assisted surgery (CAS) have been developed. We aimed to compare electromagnetic tracking for navigated procedures in frontal skull base surgery to optical tracking. METHODS: Target registration error (TRE) was determined in 6 anatomic specimens in an experimental wet-lab. As targets, 6 titanium screws were evenly distributed over the surgical areas of interest from the frontal sinus to the clivus. Optical tracking and electromagnetic tracking was evaluated in identical software environment using a last generation commercially available navigation system. RESULTS: Submillimetric application accuracy could be achieved with both tracking modalities. Optical was more accurate than electromagnetic tracking and its reliability was better. Target position did not influence TRE, however TRE varied significantly from skull to skull. CONCLUSIONS: Although less accurate than optical tracking, electromagnetic tracking still offers excellent accuracy and reliability for anterior skull base surgery. Electromagnetic tracking is not dependent on direct line of sight between its hardware components and therefore easily integrated even in cluttered operating theatres.
Об определяющих функциях и ядрах для неограниченных областей. III
Authors: Harz Tobias , Shcherbina Nikolai Vasil'evich , Tomassini Giuseppe
Published: May 2021

Предыдущие результаты авторов о существовании глобальных определяющих функций распространены на ряд новых постановок. В частности, условие строгой псевдовыпуклости области ослабляется до условия строгой $q$-псевдовыпуклости, а также рассматриваются более общие ситуации, когда объемлющее многообразие представляет собой почти комплексное многообразие или комплексное пространство. Также исследуется вопрос о том, насколько предположение о гладкости границы рассматриваемой области существенно для полученных результатов.
Библиография: 27 названий.
A Reconsideration of Grammatical Categorization in English: The Clause
Authors: Wiredu John Franklin
Published: May 2021

Various models for categorizing grammatical units exist in the literature. Particularly nebulous, however, are terminologies for conceptualizing categories at the level of the clause. For example, the term complement has been used, confusingly sometimes, as both a functional term and, on some occasions, as a structural term. In this study, a model of categorization is proposed, which keeps functional classification separate from structural classification, in order that concepts used in grammatical analysis can be clearly understood and be applied more easily in text analysis. Accordingly, the specific aim of this study is to examine some already ‘accepted’ subcategories of the dependent clause and, in the process, propose a new approach for the analysis of this clause type. This approach, it is hoped, will remove (a) semantic considerations from the analysis of these grammatical units and (b) the confusion between the notional and syntactic description of the units. In the end, this work involves a reconsideration of some traditional ways of doing grammatical categorization with the hope that it will ease identification of grammatical categories. The overall goal is to offer a more consistent and structured approach to the grammatical analysis of the clause in English.
The black hole in science journalism: A study of journalism students’ accommodation strategies of scientific writing
Authors: Coker Wincharles , S. Ngula Richmond
Published: May 2021

This study examined strategies employed by journalism students to accommodate scientific communication into public news. Data were collected from news articles of 130 journalism students, 130 science-based research articles, 3,990 minutes of interviews between scientists and trainees, and among 25 focal participants. We found that some journalism students could not adequately accommodate scientific articles into news reports due to their passive knowledge of newswriting journalese. We also observed that journalism students had difficulty in interpreting scientific research claims, and showed less resilience to cope with the angst of scientists about the journalistic profession and the humanities. The paper concluded that the accommodation of scientific communication into public news is a rigorous process that requires the active participation and praxis of journalism students.