bluuebunny/crossref_metadata_2025 huggingface dataset:
The Fermi-GBM Gamma-Ray Burst Spectral Catalog: 10 yr of Data
Authors: Poolakkil S. , Preece R. , Fletcher C. , Goldstein A. , Bhat P. N. , Bissaldi E. , Briggs M. S. , Burns E. , Cleveland W. H. , Giles M. M. , Hui C. M. , Kocevski D. , Lesage S. , Mailyan B. , Malacaria C. , Paciesas W. S. , Roberts O. J. , Veres P. , von Kienlin A. , Wilson-Hodge C. A.
Published: May 2021

We present the systematic spectral analyses of gamma-ray bursts (GRBs) detected by the Fermi Gamma-Ray Burst Monitor during its first ten years of operation. This catalog contains two types of spectra: time-integrated spectral fits and spectral fits at the brightest time bin, from 2297 GRBs, resulting in a compendium of over 18,000 spectra. The four different spectral models used for fitting the spectra were selected based on their empirical importance to the shape of many GRBs. We describe in detail our procedure and criteria for the analyses, and present the bulk results in the form of parameter distributions both in the observer frame and in the GRB rest frame. 941 GRBs from the first four years have been refitted using the same methodology as that of the 1356 GRBs in years five through ten. The data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.
The Atomic Gas Mass of Green Pea Galaxies
Authors: Kanekar N. , Ghosh T. , Rhoads J. , Malhotra S. , Harish S. , Chengalur J. N. , Jones K. M.
Published: May 2021

We have used the Arecibo Telescope and the Green Bank Telescope (GBT) to carry out a deep search for Hi 21 cm emission from a large sample of “Green Pea” galaxies, yielding 19 detections, and 21 upper limits on the Hi mass. We obtain Hi masses of M
Hi
≈ (4–300) × 108
M
⊙ for the detections, with a median Hi mass of ≈ 2.6 × 109
M
⊙; for the non-detections, the median 3σ upper limit on the Hi mass is ≈ 5.5 × 108
M
⊙. These are the first estimates of the atomic gas content of Green Pea galaxies. We find that the Hi-to-stellar mass ratio in Green Peas is consistent with trends identified in star-forming galaxies in the local universe. However, the median Hi depletion timescale in Green Peas is ≈0.6 Gyr, an order of magnitude lower than that obtained in local star-forming galaxies. This implies that Green Peas consume their atomic gas on very short timescales. A significant fraction of the Green Peas of our sample lie ≳0.6 dex (2σ) above the local M
Hi
–M

B
relation, suggesting recent gas accretion. Further, ≈30% of the Green Peas are more than ±2σ deviant from this relation, suggesting possible bimodality in the Green Pea population. We obtain a low Hi 21 cm detection rate in the Green Peas with the highest O32 ≡ [O iii]λ5007/[O ii]λ3727 luminosity ratios, O32 > 10, consistent with the high expected Lyman-continuum leakage from these galaxies.
Evidence for TiO in the Atmosphere of the Hot Jupiter HAT-P-65 b
Authors: Chen Guo , Pallé Enric , Parviainen Hannu , Murgas Felipe , Yan Fei
Published: May 2021

We present the low-resolution transmission spectra of the puffy hot Jupiter HAT-P-65b (0.53 MJup, 1.89 RJup, T
eq = 1930 K), based on two transits observed using the OSIRIS spectrograph on the 10.4 m Gran Telescopio CANARIAS. The transmission spectra of the two nights are consistent, covering the wavelength range 517–938 nm and consisting of mostly 5 nm spectral bins. We perform equilibrium-chemistry spectral retrieval analyses on the jointly fitted transmission spectrum and obtain an equilibrium temperature of

K and a cloud coverage of

%, revealing a relatively clear planetary atmosphere. Based on free-chemistry retrieval, we report strong evidence for titanium oxide (TiO). Additional individual analyses in each night reveal weak-to-moderate evidence for TiO in both nights, but moderate evidence for Na or VO only in one of the nights. Future high-resolution Doppler spectroscopy as well as emission observations will help confirm the presence of TiO and constrain its role in shaping the vertical thermal structure of HAT-P-65b’s atmosphere.
Framework for Coordinated Efforts in the Exploration of Volatiles in the South Polar Region of the Moon
Authors: Lemelin Myriam , Li Shuai , Mazarico Erwan , Siegler Matthew A. , Kring David A. , Paige David A.
Published: May 2021

The exploration of the lunar south polar region and the ground truthing of polar volatiles is one of the top priorities for several space agencies and private partners. Here we use Moon Mineralogy Mapper surficial water ice detections to investigate the location of water-ice-bearing permanently shaded regions (PSRs) near the south pole. We extract a variety of parameters such as their temperature regime, slope, hydrogen content, number of ice detections, depth stability for water ice and dry ice, and mobility aspects. We identify 169 water-ice-bearing PSRs and use their characteristics to identify sites that allow us to access the highest abundances of volatiles, sites that can be visited to characterize the lateral or vertical distribution of volatiles (water ice and dry ice), and sites that allow for the fastest recovery of a scientifically interesting sample. Collectively, 37 PSRs are identified as sites of interest, including 11 that would address more than one mission objective and may be, for that reason, higher-priority targets of exploration. These PSRs are found in Shoemaker, Faustini, Cabeus, Malapert, Nobile, Sverdrup, Wiechert J, and Haworth craters, as well as three unnamed craters (PSRs 57, 120, and 89). These sites are all located within 6° of the south pole. We present case studies for a relatively short traverse mission (20–50 km) to PSR 89, a medium-length traverse (∼100 km) to Sverdrup 1, and a longer traverse (∼300 km) to Cabeus that can serve as a guide in planning upcoming exploration missions.
A picture is worth a thousand words: using digital tools to visualize marine invertebrate diversity data along the coasts of Mozambique and São Tomé & Príncipe
Authors: Niza Henrique , Bento Marta , Lopes Luis , Cartaxana Alexandra , Correia Alexandra
Published: May 2021

The amount of biological data available in online repositories is increasing at an exponential rate. However, data on marine invertebrate biodiversity resources are still sparse and scattered in these countries. Online repositories are useful instruments for biodiversity research, as they provide a fast access to data from different sources. The use of interactive platforms comprising web mapping are becoming more important not only for the scientific community, but also for conservation managers, decision-makers and the general public as they allow data presentation in simple and understandable visual schemes. The main goal of this study was to create an interactive online digital map (MARINBIODIV Atlas), through the collection of data from various sources, to visualize marine invertebrate occurrences and distribution across different habitats, namely mangroves, seagrasses, corals and other coastal areas, in Mozambique and São Tomé and Príncipe. The acquired biodiversity data were managed and structured to be displayed as spatial data and to be disseminated using the geographic information system ArcGIS, where data can be accessed, filtered and mapped. The ArcGIS web mapping design tools were used to produce interactive maps to visualize marine invertebrate diversity information along the coasts of Mozambique and São Tomé and Príncipe, through different habitats, offering the foundation for analysing species incidence and allocation information. Understanding the spatial occurrences and distribution of marine invertebrates in both countries can provide a valuable baseline, regarding information and trends on their coastal marine biodiversity.
Return of the walking dead: First verified record of the shrew Crocidura leucodon (Hermann, 1780) in Hamburg, Germany
Authors: Klesser Robert , Jessen Frederik , Ringenberg Jörgen , Preuß Matthias , Kaiser Thomas , Husemann Martin
Published: May 2021

The bicolored shrew Crocidura leucodon so far has not been reported in Hamburg with certainty. Some plausible historical records before 1920 are present; in turn, two more recent records are doubtful for different reasons. Hence, the Red List status of the species for Hamburg has to be considered uncertain (either not present, or extinct). A citizen scientist provided a specimen of an unknown shrew, an accidental catch by a snap trap, to the Centrum für Naturkunde. The specimen was caught on the 12th of September 2019 in Tatenberg, Hamburg. It was morphologically and genetically clearly determined as C. leucodon. This find represents the first confirmed record of C. leucodon for the federal state of Hamburg and increases the number of shrew species recorded in Hamburg to five. The Red List status of the species will have to be reevaluated.
Open Source Intelligence (OSINT) : retour aux sources
Authors: Le Deuff Olivier , Roumanos Rayya
Published: May 2021

Acronyme d’ Open Source Intelligence , l’OSINT désigne un ensemble de méthodes et de techniques qui permettent d’exploiter efficacement des sources d’information librement accessibles. Née au sein des services de renseignement pour s’étendre ensuite aux domaines de la cybersécurité, de l’intelligence économique, du journalisme et, plus largement, de l’activisme citoyen, elle offre à quiconque sait manier certains outils la possibilité de mener des recherches ciblées pour repérer des informations clés, surveiller des activités suspectes et se prémunir contre les attaques. Raconter l’histoire de l’OSINT c’est revenir sur cette ouverture spectaculaire d’une pratique historiquement réservée à une poignée de professionnels pour tenter d’en déceler la portée actuelle et les limites.
Journalistes et citoyens, main dans la main ? L’exemple du Capitol Hill Project , fondé sur les méthodes de l’ Open Source Intelligence
Authors: Schwartz Arnaud
Published: May 2021

Baptisé Capitol Hill Project , le travail d’enquête journalistique mené aux États-Unis par Ronan Farrow et John Scott-Railton , dans le sillage des événements de janvier 2021 à Washington, est un exemple fort de collaboration entre citoyens et journalistes. En valorisant l’apport de chacun, les méthodes de l’Open Source Intelligence (OSINT) pourraient contribuer à réduire la défiance que les premiers expriment souvent à l’encontre des seconds.
« L’Open Source Intelligence (OSINT), c’est avant tout un état d’esprit »
Authors: Manach Jean-Marc , Le Deuff Olivier , Roumanos Rayya
Published: May 2021

Jean-Marc Manach est l’un des pionniers de l’enquête sur le numérique en France. Depuis plusieurs décennies, il puise dans les techniques propres au data journalisme et à l’OSINT les ressources nécessaires pour composer ses travaux de recherche et d’investigation. Dans cet entretien, il revient sur son parcours singulier, celui d’un outsider dont les références sont surtout celles de la contre-culture.
Les mobilisations pétitionnaires en ligne sur le survol de Bruxelles et de ses environs : du syndrome Nimby à l’effet foot-in-the-door
Authors: Contamin Jean-Gabriel , Léonard Thomas , Paye Olivier , Soubiran Thomas , Kelbel Camille
Published: May 2021

Alors que la digitalisation semble de nature à intensifier considérablement les pratiques pétitionnaires, peu d’études systématiques ont été consacrées aux e-pétitions. Basé principalement sur des données individuelles issues d’un site belge francophone de pétitions en ligne, cet article analyse la propension différenciée à l’engagement politique au travers de pétitions portant sur un enjeu spécifique : le survol de Bruxelles par les avions. Il conclut que c’est l’exposition aux nuisances environnementales et davantage encore la dotation en ressources qui expliquent les dynamiques e-pétitionnaires, nuançant ainsi la thèse de la mobilisation. Toutefois, la politisation induite permettrait parfois à l’engagement de survivre à la disparition de la nuisance et de l’intérêt « direct » des acteurs ayant mis un « pied dans la porte ».
Origines et impacts des hyper-utilisateurs et hyper-utilisatrices en cyberdémocratie. Le cas du pétitionnement en ligne
Authors: Bright Jonathan , Pilet Jean-Benoît , Soubiran Thomas , Bermudez Sandra , Carey-Libbrecht Liz
Published: May 2021

La répartition fortement inégale des niveaux d’engagement entre personnes utilisant les sites web de participation citoyenne (e-forums, sites de pétitionnement en ligne, etc.) est l’une des caractéristiques les plus connues de ces plateformes : alors que la majorité de leurs membres n’y participe que très peu, une petite minorité, souvent qualifiée d’« hyper-utilisatrice » ( power users ), y contribue abondamment. Cette minorité est sous-étudiée dans le corpus actuel de recherches portant sur la participation en cyberdémocratie ; cet article vise à combler cette lacune. En nous appuyant sur un jeu de données observationnelles unique, portant sur des centaines de milliers de personnes utilisant une plateforme de pétitions en ligne, nous montrerons que la quantité de temps libre, ainsi que le fait d’avoir eu un premier contact positif avec le site, sont des facteurs en favorisant un usage intensif. Nous montrerons également que les « hyper-utilisateurs et utilisatrices » sont plus efficaces que les membres habituels de ces sites dans leurs entreprises de mobilisation collective, mais que leurs centres d’intérêt diffèrent considérablement de ceux de la majorité utilisant moins intensivement ces sites. Cela signifie, globalement, que ces petits groupes exercent une puissante influence sur ces sites, avec un effet de distorsion à la clé.
Pétitions électroniques au Québec : entre transfert et résistance
Authors: Montigny Eric , Brennan Audrey
Published: May 2021

En 2009, l’Assemblée nationale du Québec a introduit les e-pétitions. Cette réforme a-t-elle modifié l’agenda parlementaire et contribué à davantage de participation citoyenne ? Il s’avère que les élus ne se sont pas véritablement approprié les nouveaux mécanismes de suivi des pétitions. Seuls des enjeux qui transcendent les clivages partisans ont fait l’objet d’une étude approfondie en commission. Pour attaquer le gouvernement et recueillir des données personnelles, les partis optent plutôt pour leurs propres plateformes. Nous constatons enfin une hausse du nombre de pétitions, sans pour autant que ce phénomène se traduise par une augmentation du nombre de signataires.
Quand le pétitionnement contribue au façonnage de l’agenda politique. L’abolition de la tenure seigneuriale au Canada français (1849-1854)
Authors: Carpenter Daniel
Published: May 2021

On reproche souvent aux pétitions de n’avoir aucune efficacité dans le champ des politiques réelles. Or, l’histoire politique de la démocratisation nord-américaine nous montre que les pétitionnaires peuvent changer la donne et façonner l’agenda politique. Dans les années 1840 et 1850, les Bas-Canadiens (aujourd’hui, les Québécois) débattent de la question de la tenure seigneuriale, et des mécanismes pour la remplacer par une tenure allodiale (soit par une abolition immédiate, soit par une commutation, soit par une réforme plus graduelle). Après des décennies de débats, le Bas-Canada ne parvient pas à réformer la tenure seigneuriale. Mais à partir de 1849, les réformistes pétitionnent massivement, avec des demandes de plus en plus souvent écrites en français et de plus en plus radicales. L’agenda politique se transforme, et le Bas-Canada abolit la tenure seigneuriale en 1854.
Probiotic Escherichia coli Nissle inhibits IL-6 and MAPK-mediated cardiac hypertrophy during STZ-induced diabetes in rats
Authors: Chiang C.J. , Chao Y.P. , Ali A. , Day C.H. , Ho T.J. , Wang P.N. , Lin S.C. , Padma V.V. , Kuo W.W. , Huang C.Y.
Published: May 2021

Escherichia coliNissle (EcN), a probiotic bacterium protects against several disorders. Multiple reports have studied the pathways involved in cardiac hypertrophy. However, the effects of probiotic EcN against diabetes-induced cardiac hypertrophy remain to be understood. We administered five weeks old Wistar male (271±19.4 g body weight) streptozotocin-induced diabetic rats with 109cfu of EcN via oral gavage every day for 24 days followed by subjecting the rats to echocardiography to analyse the cardiac parameters. Overexpressed interleukin (IL)-6 induced the MEK5/ERK5, JAK2/STAT3, and MAPK signalling cascades in streptozotocin-induced diabetic rats. Further, the upregulation of calcineurin, NFATc3, and p-GATA4 led to the elevation of hypertrophy markers, such as atrial and B-type natriuretic peptides. In contrast, diabetic rats supplemented with probiotic EcN exhibited significant downregulated IL-6. Moreover, the MEK5/ERK5 and JAK2/STAT3 cascades involved during eccentric hypertrophy and MAPK signalling, including phosphorylated MEK, ERK, JNK, and p-38, were significantly attenuated in diabetic rats after supplementation of EcN. Western blotting and immunofluorescence revealed the significant downregulation of NFATc3 and downstream mediators, thereby resulting in the impairment of cardiac hypertrophy. Taken together, the findings demonstrate that supplementing probiotic EcN has the potential to show cardioprotective effects by inhibiting diabetes-induced cardiomyopathies.
Validation of an analytical method based on QuEChERS and LC-MS/MS to quantify nine mycotoxins in plant-based milk
Authors: Pinto L. , Santos A. , Vargas E. , Madureira F. , Faria A. , Augusti R.
Published: May 2021

Plant-based beverages (popularly known as vegetable milk) have become increasingly important in recent years. However, the nonexistence of information on mycotoxin contamination is noticeable. We herein describe the development and validation of an analytical methodology that employs QuEChERS and LC-MS/MS for the simultaneous determination of nine mycotoxins (aflatoxins B1, B2, G1, and G2, fumonisins B1 and B2, ochratoxin A, zearalenone, and citreoviridin) in seven types of vegetable milk (peanut, oat, rice, cashew, maize, soybean, and coconut). The method provided the following quantification limits, recoveries at the lowest validated concentration and relative standard deviations under repeatability conditions at the lowest validated concentration, respectively: aflatoxin B1 (0.023 μg/l, 84.98 and 9.23%); aflatoxin B2 (0.024 μg/, 93.00 and 4.85%); aflatoxin G1 (0.057 μg/l, 98.85 and 5.53%); aflatoxin G2 (0.031 μg/l, 96.64 and 4.08%); fumonisin B1 (2.166 μg/l, 75.55 and 16.78%); fumonisin B2 (1.105 μg/l, 70.47 and 11.89%); ochratoxin A (0.104 μg/l, 72.05 and 5.12%); zearalenone (8.093 μg/l, 107.10 and 6.37%); citreoviridin (1.305 μg/l, 97.25 and 7.28%). The method uses small amounts of samples, solvents, and other inexpensive reagents with no need for laborious clean-up and pre-concentration steps. Its attractive characteristics (simplicity, low cost compared to procedures that use immunoaffinity columns, and full compatibility with routine analyses) make it potentially valuable. As a proof-of-principle, the validated methodology was applied to seven commercial samples of different compositions showing that some were contaminated with aflatoxins and ochratoxin A.
A Systematic Review of Augmented Reality Applications in Language Learning
Authors: Majid Siti Norzaimalina Abd , Salam Abdul Rahim
Published: May 2021

Augmented reality (AR) is one of the emerging technologies gradually venturing into the education field. Although AR is strongly linked to subjects related to Science, Mathematics, and Technology in schools and tertiary education, there is no mention of AR in non-technical subjects, such as language. Thus, this study aims to discover the AR application trends in language learning and the language skills prevalent in AR usage. In this systematic literature review, AR-related research in language learning began in 2016 and has continued to be on the rise. Furthermore, the preferred language skills used with AR technology required lower cognitive levels, such as identifying words, understanding meanings, and spelling, and pronouncing words. Based on the gap indicating the rare usage of AR for more complex and critical language skills, such as reading and writing, this study hopes to enlighten the researchers, educators, and application developers to focus on developing AR applications for languages other than English, incorporate higher-order learning outcomes in the language learning activities, and pursue qualitative investigations.
Establishing Continuous App Improvement by Considering Heterogenous Data Sources
Authors: Scherr Simon André , Hupp Steffen , Elberzhager Frank
Published: May 2021

Mobile apps have penetrated the market and are being used every­where. Companies developing apps face increasing challenges such as short time to market or demand for high quality. Furthermore, the success of an app also depends on how users perceive its quality. Feedback provided by users influences other potential users and provides new opportunities for identifying features. Consequently, it is a valuable source of input for app developers with respect to product improvements. One form is textual feedback. This kind of feedback is usually distributed across various data sources. Therefore, it must be captured from these sources and put into one single pool of data before it can be analyzed. The analysis must take into account the peculiarities of the short release cycles and high change rate of features for mobile apps. In this article, we present User Echo Service (UES), which was built to address heterogeneous data sources.  The aim of UES is to allow product managers to be able to be always up to date with the latest feedback data. Therefore, we have created an extensible architecture aimed at supporting different data sources and present the feedback collection scheduling system. This forms the prerequisite for subsequent analyses of the collected data. We discuss our solution and provide ideas for future development.
Mobile-Assisted Writing Instruction: Affordances, Challenges, and Future Directions
Authors: Zhang Xiaodong
Published: May 2021

Mobile-assisted language learning (MALL) is popular worldwide. One related issue under discussion is how to effectively harness mobile devices to help English writers. This paper first unpacks writing as a meaning making process from the perspective of systemic functional linguistics. It then summarizes the major MALL-based studies on writing instruction, including the affordances and challenges of MALL-based writing instruction. This paper then discusses how to address challenges as identified in the existing studies on MALL-based writing instruction, centering on writing as a meaning making process. The paper ends with pedagogical tips for educators who are interested in using mobile technology to comprehensively improve students’ English writing construction across different contexts.
Mobile Phones in Classrooms and in Professor-Student Communication: Ukrainian, Omani, and U.S. American College Students’ Perceptions and Practices
Authors: Tovares Alla V. , Gordon Cynthia , Al Zidjaly Najma
Published: May 2021

The unprecedented expansion of wireless technologies and the global pandemic of 2020-2021, which forced many educational establishments out of traditional face-to-face and into online instructional environments, have created an urgency for achieving a better understanding of the various education-related uses of mobile phones, and students’ attitudes toward them, worldwide. We conducted a questionnaire-based study to explore college undergraduate students’ perceptions and uses of mobile phones, with a focus on instructor-student communication and classroom use, across three diverse cultural contexts: Ukraine, Oman, and the United States. Based on our findings, we suggest that conceptualizing mobile phones as cultural tools and situating their use within cultural discourses illuminates how – and explains why – mobile phones are not “the same” tools for all students. The findings offer insights into students’ (developing) perspectives on uses of mobile phones, and provide grounds from which to formulate productive, and culturally appropriate, means of using them for educational purposes.

 
Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites
Authors: Sabirova G.A. , Safin R.R. , Galyavetdinov N.R.
Published: May 2021

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus.
We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.
Physicochemical WPC Modification Techniques
Authors: Shkuro A.E. , Artyomov A.V. , Savinovskikh A.V.
Published: May 2021

The paper studies issues related to physicochemical and chemical techniques for the modification of wood-polymer composites with a thermoplastic polymer matrix (WPCs) to improve their physical and mechanical properties. The physicochemical modification was performed by photochemical crosslinking with the exposure of WPC specimens to UV irradiation. Chemical modification was performed by introducing benzoyl peroxide into the material composition, leading to chemical crosslinking of polyethylene macromolecules of the WPC polymer matrix. As a result of the study, quantitative characteristics of the effect of the benzoyl peroxide content in the composite, as well as the WPC specimen UV irradiation intensity and duration on the basic physical and mechanical properties of the material have been obtained. The efficiency of physicochemical techniques for modifying WPCs has been estimated by changing the specimen properties such as Brinell hardness, water absorption, and impact strength. It has been found that the Brinell hardness increases by 80 % as compared to unmodified WPC specimens. Effective modification of wood-polymer composites with polymer matrices based on high-density polyethylene may lead to a significant improvement in the quality of products made of these materials.
Synthesis of 5-Hydroxymethylfurfural-Acetone Resins
Authors: Shabliy Ekaterina A. , Klushin Victor A. , Smirnova Nina V.
Published: May 2021

5-hydroxymethylfurfural-acetone (5-HMFA) resins are obtained on the basis of 5-hydroxymethylfurfural (5-HMF) and acetone, that is, from monomers whose source of raw materials is renewable resources (agricultural waste). The 5-HMFA condensation reaction was carried out under various experimental conditions. The synthesis conditions for 5-HMFA were selected with a yield of the desired product of 51%. The resulting resins were pressed at various curing temperatures and tested for compressive strength and absorption of water. The optimum pressing temperature was set to 180 ° C. The resulting composites have a strength not inferior to the strength of phenol-formaldehyde resin composites, but have a 3 times higher water resistance.
Microstructure-Impact Toughness Relationships in Quenched and Tempered Low Carbon Low Alloy Steels
Authors: Kantor M. , Vorkachev K. , Solntsev K.
Published: May 2021

The quantitative microstructure - impact toughness relationships in two batches of the same steel grade subjected to quenching and tempering (Q&T) have been established via characterization using EBSD technique and FIB visualization. The EBSD-based criterion for separation of structural constituents in microstructure of Q&T low carbon low alloy steels is proposed. Impact toughness differences between two steel batches subjected to nominally identical Q&T are caused by the changes in the volume fraction of structural constituents caused by various cooling conditions at quenching stage. High volume fraction of bainite containing more distorted bainitic ferrite and the highest amount of brittle cementite precipitates leads to the increase in strength and to the decrease in impact toughness.
Features of Structural-Phase Transformations during Oxidation of Metals with Bulk Submicrocrystalline Structure and Fine Metal Powders
Authors: Korshunov A.V.
Published: May 2021

The oxidation processes for compact and powdery samples of titanium, copper, and molybdenum with different volume structure and dispersivity were studied using thermal analysis, electron microscopy, and X-ray diffraction. It is established that producing of metals with a modified structure under conditions of high-energy impact (severe plastic deformation, electric explosion of a thin wire) in accordance with intermediate annealing leads to an increase in the content of oxygen in the form of solid solutions and oxides; the oxide component’s share, form and localization within the material depend on physicochemical properties of both metal and oxide . It is shown that the structural-phase transformations of the oxide component during heating of fine-grained metals and powders have a significant effect on the parameters of the oxidation process of such materials. The thermally induced effects in the oxygen-containing components might play a critical role for the structure stability during long-term use of such materials under cyclic thermomechanical impacts.
Thermotropic Copolyesters Based on Polyethylene Terephthalate and 4-Hydroxybenzoic Acid for High Modulus Fibers
Authors: Deberdeev T.R. , Akhmetshina A.I. , Grishin S.V.
Published: May 2021

The copolyesters derived from dimethyl ester of terephthalic acid, ethylene glycol, and 4-hydroxybenzoic acid (HBA) have been synthesized via catalytically promoted polycondensation omitting the acetylation step. FTIR spectroscopy results have evidenced an insertion of HBA along a polymer backbone. Of note, thermal gravimetric analysis has shown that the HBA moieties substantially improved the thermal stability of polyesters. As found by differential scanning calorimetry and polarizing microscopy, the copolyesters are capable of forming an anisotropic phase in a temperature range of 150-170 °C. Additionally, the free surface energy of the samples was determined to evaluate the compatibility of thermotropic copolyesters with other high-molecular compounds.
Study of the Impact of Protective Process Agents with Carbon Nanopowder Additives on Chip Forming Processes
Authors: Petrovsky E.A. , Bashmur K.A. , Tynchenko Vadim S.
Published: May 2021

The present study describes the impact of various protective process agents on chip forming processes. The research was conducted on NiCr20TiAl and 34NiCrMoV14-5 nickel-chromium alloys. New lubricant-cooling process agents with carbon nanopowder additives are studied. The optimal composition of the nanopowder additive and its effect during alloy cutting is examined. Experiments reveal the dependence of shrinkage ratio on cutting speed and various protective process agents. The values of H50 microhardness are also defined when cutting these alloys using protective process agents. Experimental studies found the positive effect of developed agents with nanopowder additives on the processes of NiCr20TiAl and 34NiCrMoV14-5 alloys chip formation.
Structural-Mechanical Properties of Polyurethane Surface after Carbon Ion Subplantation
Authors: Morozov I.A. , Kamenetskikh A.S.
Published: May 2021

Ion-plasma modification of polymers has many potential applications, in particular, in the development of biomedical products. Treatment of soft polymers can easily damage the surface; low-energy plasma and subsequent investigation of the structural and mechanical properties of the surface are required. Polyurethane is a widely used block copolymer. Subplantation of carbon ions heterogeneously changes the structural and mechanical properties of the surface (relief, stiffness, thickness of the modified coating), forming a graphene-like nanolayer. Uniaxial deformation of the treated materials in some cases leads to the damage of the surface (local nanocracks, folds). Materials have increased hydrophobicity, good deformability (valid for certain treatment regimes) and can find application in design of products with improved biomedical properties.
The Effect Covering on the Change in the Properties of Hard Alloys
Authors: Bogodukhov S.I. , Kozik E.S. , Svidenko E.V , Garipov V.S.
Published: May 2021

Currently, hard alloys are common tool materials; they are widely used in the tool manufacturing industry. Due to the presence of refractory carbides in its structure, hard-alloy tools feature a high hardness of 80 to 92 HRA (73 to 76 HRC); a high heat resistance (from 800 °С to 1,000 °С); therefore, they can be used at speeds that are several times higher than cutting speeds of high-speed steel grades. Hard alloys are used in the form of plates that are either mechanically fixed on or soldered to tool holders. The main operational parameters, that determine the hard-alloy tool operation mode, are hardness, wear resistance, and bending strength. The operational parameters of alloy are highly dependent on its structure, phase composition, lattice block sizes, and micro-stress values [1-20]. The main methods to enhance physical and mechanical properties of hard-alloy plates are improvement of manufacturing technology, including production of fine-grained alloys and microalloying, as well as applying composite coating by vacuum deposition, which allows to increase the tool resistance 1.5 to 2 times.
Cement Building Materials with Powdered Optical Discs as a Filler
Authors: Ezerskiy V. , Kuznetsova N.V. , Seleznev A.D.
Published: May 2021

The object of study is a cement composite material with powdered utilized optical discs. The objective is to establish the dependences of the main strength characteristics – com-pressive strength, bending strength, and density – on the amount of waste added into the mix-ture and the water-cement ratio.The compositions of the mixtures for the production of the cement composite material samples consisted of the following components: cement, sand, powdered waste in the form of utilized optical discs and water.Based on the results of testing the samples, mathematical models have been developed which describe the dependences of the physical and mechanical properties of the cement com-posite material samples on the fraction of waste and water-cement ratio. It was found that with an increase in the amount of powdered waste added into the mixture, it reduces the compressive strength, bending strength, and density of the samples under study, however, the optimization of the water-cement ratio makes it possible to obtain equal strength compositions with a differ-ent fraction of waste.Component compositions of cement composite material mixtures with the addition of powdered utilized optical discs in the amount of 10 to 25 % of the total filler mass, which can provide construction products with a compressive strength class B20, are presented.
Assessment of the Impact of High Temperature on the Strength of Reinforced Concrete Structures during Operation
Authors: Rimshin V.I. , Telichenko V.I. , Krishan A.L. , Truntov P.S. , Bykov G.S.
Published: May 2021

Presented here are the results of assessing the effect of elevated temperature on the strength characteristics of reinforced concrete structures during operation. Described here are the features of the technical inspection of structures subjected to temperature effects (after a fire). The strength class of reinforced concrete structures was determined before temperature exposure (in places that were not exposed to fire) and after in the course of the study. Presented are the results of measuring the strength of concrete by the direct method of pulling off with spalling, as well as the results of verification calculations of reinforced concrete structures exposed to temperature effects. When performing verification calculations, the percentage of reduction in the bearing capacity of structures was established. Based on the results of the study, the percentage ratio of the decrease in the strength of prefabricated reinforced concrete structures after a fire during the operation of the facility was established.
Effect of Cement Paste Preparation Procedure and Cement Stone Age on its Phase Composition
Authors: Maksimova I.N. , Makridin N.I. , Dergunova Anna V. , Babenkova Yu.V.
Published: May 2021

Self-levelling and self-consolidating concrete mixtures formed with the use of superplasticizers are worthwhile for the manufacture of reinforced concrete structures. It is important to evenly distribute not only the mixing water in the system, but also the dissociated plasticizer ions for cement dispersed compositions with plasticizing additives. It is established that the optimal sequence of loading and mixing of the components of a cement composition is not only a promising direction for intensifying the manufacture of concrete building structures, but also a tool for improving the mechanical properties of cement brick and concrete made on its basis, as well as for increasing its durability and reliability. When superplasticizers are introduced into the pre-ground cement paste, the rheological properties of the compositions are improved, as well as the structure of the hardened composites. The given article is devoted to the study of the effect of the procedural factor and the duration of mixing of highly concentrated cement compositions with the addition of a superplasticizer based on naphthalene sulfonic acid (SP C-3) on the phase composition of hardened composites during various periods of hydration. Experimental results were obtained using the X-ray phase analysis method. Tested are 15 series of samples of cement stone with W/C ratio range between 0,18 and 0,27 and SP C-3 between 0 and 1.0 % by cement weight. Comparing the phase composition of cement stone after 28 days of hardening with that of 4,5 years, it was found that at first the C3SH2 phase, particularly enriched with calcium oxide, is formed, which decays over time and disappears in the 4,5-year hardening amples.
Sulfide Technology Based on Sulfur Waste Product of Coke Production
Authors: Yusupova A.A. , Baraeva L.R. , Bobrishev A.A.
Published: May 2021

A technology has been developed for the processing recycling of waste - sulfuric cake into building materials with high physical and mechanical characteristics. Sulfur activator (zinc chloride) contributed to the chemical bonding of the components.
Determination of the Chemical Composition of Corrosion Defects on the Inner Surfaces of Hollow Reinforced Concrete Structures
Authors: Bryukhova A.S. , Volkova N.V. , Kuznetsov A.A. , Kuzmenko A.Yu.
Published: May 2021

The paper presents the results of experimental studies on the determination of corrosion products on the surface of reinforced concrete structures. This paper also discusses methods for creating samples with artificial electro corrosion under conditions close to real operation. The paper presents the results of testing samples using laser-inducted breakdown spectrometry (LIBS) devices.
The Construction of the Diagrammatic Deformation Model for Calculating the Core Reinforced-Concrete Structures in Finite Increments under Joint Action of Load Increments and Variable by Cross Sections Low and Ultra Low Subzero Temperatures
Authors: Karpenko N.I. , Karpenko S.N. , Kadiev D.Z. , Moiseenko G.A.
Published: May 2021

The use of the nonlinear deformation model in computer calculation methods involves the use of time-consuming step-iteration methods for solving systems of resolving equations with problems of convergence. To eliminate these difficulties, the physical relations of the deformation model are established in finite increments. The article considers the construction of such a model in finite increments as applied to the calculation of the core reinforced-concrete structures in the overall case of oblique bending and oblique eccentric compression or tension, taking into account the action by the cross sections of low subzero temperatures.
Strain-Stress Distribution of Structural Components from Foam Concrete for Monolithic Construction
Authors: Novikov M.V. , Chernyshov E.M. , Prokshits E.E.
Published: May 2021

The problem of use of hi-tech macroporous concrete in load-carrying structures of low-rise buildings is designated and the forthcoming research problems of power resistance and deformation of the compressed and bent elements from foam concrete of natural solidification are formulated. Results of pilot researches of intense state of strain of the compressed and bent elements from foam concrete of average density of 1200-1600 kg/m3 of different structural modification in the conditions of short-term and long action of loading are provided. It is established that foam concrete meet for nonrigid indicators regulatory requirements and take the intermediate place between full-strength cellular and light concrete on expanded aggregates that creates premises for their successful application in the bearing concrete and reinforced concrete constructions. Deformation and strength characteristics of foam concrete of different structural modifications taking into account the impact of the long processes caused by solidification of concrete and external power factors, necessary for calculation and structural design are offered. The received results of researches will allow to project rationally bearing and enclosing structures from foam concrete that leads to increase in technological level of monolithic construction.
Research Investigation of Deformation Characteristics of Thin Polymer Films at Different Doses of Electron Irradiation
Authors: Niyazov Marat N. , Kupchishin Anatoliy I. , Taipova Buvkhan G.
Published: May 2021

The study of the deformation characteristics of thin polymer films has established 2 stages of increasing strain with increasing stress: the first stage in the elastic region is slow linear; the second stage is sharply exponential. The dependence of deformation (ε) on stress (σ) in polytetrafluoroethylene at various exposure doses has been experimentally investigated. Irradiation of the fluoroplastic films under study with electrons doses of 1, 3, 5, 7, and 10 kGy leads to significant changes in their mechanical properties, while the samples lose their plasticity and begin to break at a lower strain, which is associated with the formation of nanodefects in the structure of the material. A significant decrease in elongation is observed compared with unirradiated material. The reason for this is the degradation of the main chains of the fluoroplastic. With an increase in the absorbed dose, the Young's modulus increases exponentially, which is associated with a decrease in the distance between atoms in the structure of the sample. The resulting effect can be used in industry. The curves obtained for both non-irradiated and irradiated material are satisfactorily described in the exponential model.
Thermal Decomposition Characteristics of Poly((4-Vinylbenzyl) Trimethylammonium Bis (Trifluoromethanesulfonimide)) Studied by Pyrolysis-GS / MS
Authors: Atlaskin A.A. , Andronova A.A. , Kazarina O.V.
Published: May 2021

Over the past decades, significant advances have been made in the development and research of gas separation membranes based on ionic liquids (IL) and their polymer analogs (PIL) for membrane separation of "acid gases" such as CO2 and H2S from gas mixtures. Polymers containing various amino groups are of great interest for the selective separation of acid gases from gas mixtures, since ammonia and its derivatives are used in conventional purification. In this work, we have synthesized a monomeric ionic liquid based on 4 vinylbenzyl chloride with included triethylamine by the Menshutkin reaction. Further, on its basis, polymer ionic liquids were obtained by the method of free radical polymerization, then an anion exchange reaction was carried out to replace the Cl anion with Tf2N. To analyze the process of thermal pyrolysis of poly [VBTEA-Tf2N] a pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS) was employed in this research. The obtained materials, which are high molecular weight compounds, can be used to obtain polymer membranes of various architectures by traditional methods: both non-porous symmetric membranes and microporous asymmetric membranes.
Functional Outcome and Community Reintegration of Survivors Following Disasters
Authors: Lee Su Yi , Mansoor Sahibzada Nasir , Amatya Bhasker , Sayed Tahir M. , Galea Mary P. , Khan Fary
Published: May 2021

Objective:

The objective of the study is to evaluate functional outcomes and community reintegration of disaster survivors in Pakistan.

Methods:

This was a cross-sectional descriptive study of community-based participants at the Armed Forces Institute of Rehabilitation Medicine, Pakistan. The medical records were screened for eligibility of adults with disaster-related disability. Participants were interviewed in ambulatory clinics using validated measures: Neurological-Trauma Impairment Scale (NIS-Trauma), International Classification of Functioning, Disability, and Health-Generic Set, Community Integration Measure (CIM), Community Integration Questionnaire (CIQ), and EuroQol 5-Dimension 5-Level.

Results:

Participants were (n = 117, mean age = 35 years) with postdisaster injury up to 17 years; the majority had spinal cord injury (n = 62; 53%) and amputations (n = 44; 38%). At assessment, 80% were independent with mobility (with aids) and 29% with everyday living activities. They reported ongoing fatigue (54.7%), altered sensations (51.28%), and pain (50.43%), but fewer problems with mood and emotions. The impairment severity negatively impacted community activities (NIS-Trauma vs. CIQ: P < 0.001). As impairments improved with time (NIS-Trauma vs. time since injury: P = 0.003), so did community reintegration (time since injury vs. CIQ; P < 0.001) and perceived health status (time since injury vs. EuroQol; P = 0.001).

Conclusion:

Many participants reported various ongoing disability-related issues; however, majority were dependent with everyday living activities and well adapted in the community. Further robust studies are needed for evaluation of longer-term impact of the disability in disaster victims for the comprehensive healthcare in the community.