Особливості процесів синтезу, мікроструктура і властивості стронцій-анортитової кераміки, модифікованої склом сподуменового складу

To create heat-resistant structural materials capable of operating at high temperatures (up to 1,400 °C), glass crystalline materials based on the SrO–Al2O3–SiO2 system are promising.This paperreports the results of studying strontium-anorthite ceramics modified with boron-containing glass of the spodumene composition. It was established that in order to achieve a set of high physical and technical indicators of ceramics at reduced firing temperatures (1,200‒1,300 °C), it is necessary to introduce glass in the amount of 20‒30 % by weight. In this case, densely baked materials with low TCLE values were obtained (32.0–33.4)·10-7 degrees-7, which predetermine their high thermal resistance (not lower than 850 °C). The principal crystalline phase of the examined ceramics is a monoclinic modification of strontium anorthite that mainly forms its microstructure. The strontium anorthite crystals measuring from 1‒2 µm to 3–4 µm are tightly connected via thin layers of the residual glass phase. In the glass phase, the β-spodumene crystals the size of 0.1–0.3 µm are evenly distributed. The observed microstructure features of ceramics determine zero values of water absorption and open porosity, as well as high density values (2.40–2.50 g/cm3) and mechanical compression strength values (237–246 MPa). The dense microstructure also makes it possible to achieve high dielectric indicators (ε=4.4–4.8; tgδ=0.005–0.007) in an ultra-high-frequency electromagnetic field. Therefore, the designed materials are promising as radio-translucent materials, including structural ones. In addition, the enrichment of the residual glass phase with the refractory components of the SAS system in the process of firing the examined ceramics predetermines its increased resistance to high-temperature heating during operationДля создания термостойких конструкционных материалов, способных работать в условиях высоких температур (до 1400 °С), перспективными являются стеклокристаллические материалы на основе системы SrO–Al2O3–SiO2.В статье приведены результаты исследований стронций-анортитовой керамики, модифицированной борсодержащим стеклом сподуменового состава. Установлено, что для достижения комплекса высоких физико-технических показателей керамики при пониженной температуре обжига (1200–1300 °С) необходимо вводить стекло в количестве 20–30 мас. %. При этом получены плотно спеченные материалы с низкими значениями ТКЛР (32,0–33,4)·10–7 град–7, что обуславливает их высокую термическую стойкость (не ниже 850 °С). Основной кристаллической фазой опытной керамики является моноклинная модификация стронциевого анортита, который преимущественно и формирует ее микроструктуру. Кристаллы стронциевого анортита размером от 1–2 мкм до 3–4 мкм плотно соединены между собой с помощью тонких прослоек остаточной стеклофазы. В стеклофазе равномерно распределены кристаллы β-сподумена размером 0,1–0,3 мкм.Отмеченные микроструктурные особенности керамики определяют нулевые значения водопоглощения и открытой пористости, а также высокие значения плотности (2,40–2,50 г/см3) и механической прочности на сжатие (237–246 МПа). Плотная микроструктура также позволяет достигать высоких диэлектрических показателей (ε=4,4–4,8; tgδ=0,005–0,007) в сверхвысокочастотном электромагнитном поле. Поэтому разработанные материалы являются перспективными в качестве радиопрозрачных материалов, в том числе и конструкционных. Кроме того, обогащение остаточной стеклофазы тугоплавкими компонентами SAS системы в процессе обжига опытной керамики обуславливает повышенную ее устойчивость к высокотемпературному нагреву в период эксплуатацииДля створення термостійких конструкційних матеріалів, здатних працювати в умовах високих температур (до 1400 °С), перспективними є склокристалічні матеріали на основі системи SrO–Al2O3–SiO2.В статті наведені результати досліджень стронцій-анортитової кераміки, модифікованої борвмісним склом сподуменового складу. Встановлено, що для досягнення комплексу високих фізико-технічних показників кераміки при знижених температурах випалу (1200–1300 °С) необхідно вводити скло в кількості 20–30 мас. %. При цьому отримані щільно спечені матеріали з низькими значеннями ТКЛР (32,0–33,4)·10–7 град–7, що обумовлює їх високу термічну стійкість (не нижче 850 °С). Основною кристалічною фазою дослідної кераміки є моноклінна модифікація стронцієвого анортиту, який переважно і формує її мікроструктуру. Кристали стронцієвого анортиту розміром від 1–2 мкм до 3–4 мкм щільно сполучені між собою за допомогою тонких прошарків залишкової склофази. В склофазі рівномірно розподілені кристали β-сподумену розміром 0,1–0,3 мкм. Відмічені мікроструктурні особливості кераміки визначають нульові значення водопоглинання і відкритої пористості, а також високі значення щільності (2,40–2,50 г/см3) і механічної міцності на стискання (237–246 МПа). Щільна мікроструктура також дає можливість досягати високих діелектричних показників (ε=4,4–4,8; tgδ=0,005–0,007) у надвисокочастотному електромагнітному полі. Тому матеріали, які розробляються, є перспективними в якості радіопрозорих матеріалів, в тому числі і конструкційних. Крім того, збагачення залишкової склофази тугоплавкими компонентами SAS системи в процесі випалу дослідної кераміки обумовлює підвищену її стійкість до високотемпературного нагрівання в період експлуатаці

The muon deficit problem: a new method to calculate the muon rescaling factors and the Heitler-Matthews beta exponent

Simulations of extensive air showers using current hadronic interaction models predict too small numbers of muons compared to events observed in the air-shower experiments, which is known as the muon-deficit problem. In this work, we present a new method to calculate the factor by which the muon signal obtained via Monte-Carlo simulations must be rescaled to match the data, as well as the beta exponent from the Heitler-Matthews model which governs the number of muons found in an extensive air shower as a function of the mass and the energy of the primary cosmic ray. This method uses the so-called z variable (difference between the total reconstructed and the simulated signals), which is connected to the muon signal and is roughly independent of the zenith angle, but depends on the mass of the primary cosmic ray. Using a mock dataset built from QGSJetII-04, we show that such a method allows us to reproduce the average muon signal from this dataset using Monte-Carlo events generated with the EPOS-LHC hadronic model, with accuracy better than 6%. As a consequence of the good recovery of the muon signal for each primary included in the analysis, also the beta exponent can be obtained with accuracy of less than 1% for the studied system. Detailed simulations show a dependence of the beta exponent on hadronic interaction properties, thus the determination of this parameter is important for understanding the muon deficit problem.Comment: 8 pages, 5 figures, 2 tables, accepted for publication in the proceedings of the 27th European Cosmic Ray Symposiu

Calculation of rescaling factors and nuclear multiplication of muons in extensive air showers

Recent results obtained from leading cosmic ray experiments indicate that simulations using LHC-tuned hadronic interaction models underestimate the number of muons in extensive air showers compared to experimental data. This is the so-called muon deficit problem. Determination of the muon component in the air shower is crucial for inferring the mass of the primary particle, which is a key ingredient in the efforts to pinpoint the sources of ultra-high energy cosmic rays.In this paper, we present a new method to derive the muon signal in detectors, which uses the difference between the total reconstructed (data) and simulated signals is roughly independent of the zenith angle, but depends on the mass of the primary cosmic ray. Such a method offers an opportunity not only to test/calibrate the hadronic interaction models, but also to derive the $\beta$ exponent, which describes an increase of the number of muons in a shower as a function of the energy and mass of the primary cosmic ray. Detailed simulations show a dependence of the $\beta$ exponent on hadronic interaction properties, thus the determination of this parameter is important for understanding the muon deficit problem. We validate the method by using Monte Carlo simulations for the EPOS-LHC and QGSJetII-04 hadronic interaction models, and showing that this method allows us to recover the ratio of the muon signal between EPOS-LHC and QGSJetII-04 and the average $\beta$ exponent for the studied system, within less than a few percent. This is a consequence of the good recovery of the muon signal for each primary included in the analysis.Comment: This work corresponds to the presentation at the ICNFP 2022 at Kolymbari, Crete, in September 2022. The proceedings will be published in Physica Scripta. arXiv admin note: text overlap with arXiv:2108.0752

Method for calculation of the beta exponent from the Heitler-Matthews model of hadronic air showers

The number of muons in an air shower is a strong indicator of the mass of the primary particle and increases with a small power of the cosmic ray mass by the $\beta$-exponent, $N_{\mu} \sim A^{(1-\beta)}$. This behaviour can be explained in terms of the Heitler-Matthews model of hadronic air showers. In this paper, we present a method for calculating $\beta$ from the Heitler-Matthews model. The method has been successfully verified with a series of simulated events observed by the Pierre Auger Observatory at $10^{19}$ eV. To follow real measurements of the mass composition at this energy, the generated sample consists of a certain fraction of events produced with p, He, N and Fe primary energies. Since hadronic interactions at the highest energies can differ from those observed at energies reached by terrestrial accelerators, we generate a mock data set with $\beta =0.92$ (the canonical value) and $\beta =0.96$ (a more exotic scenario). The method can be applied to measured events to determine the muon signal for each primary particle as well as the muon scaling factor and the $\beta$-exponent. Determining the $\beta$-exponent can effectively constrain the parameters that govern hadronic interactions and help solve the so-called muon problem, where hadronic interaction models predict too few muons relative to observed events. In this paper, we lay the foundation for the future analysis of measured data from the Pierre Auger Observatory with a simulation study.Comment: Proccedings of 38th International Cosmic Ray Conference (ICRC2023

The muon deficit problem: a new method to calculate the muon rescaling factors and the Heitler-Matthews β exponent

Simulations of extensive air showers using current hadronic interaction models predict too small numbers of muons compared to events observed in the air-shower experiments, which is known as the muon-deficit problem. In this work, we present a new method to calculate the factor by which the muon signal obtained via Monte-Carlo simulations must be rescaled to match the data, as well as the exponent from the Heitler-Matthews model which governs the number of muons found in an extensive air shower as a function of the mass and the energy of the primary cosmic ray. This method uses the so-called variable (difference between the total reconstructed and the simulated signals), which is connected to the muon signal and is roughly independent of the zenith angle, but depends on the mass of the primary cosmic ray. Using a mock dataset built from QGSJetII-04, we show that such a method allows us to reproduce the average muon signal from this dataset using Monte-Carlo events generated with the EPOS-LHC hadronic model, with accuracy better than 6%. As a consequence of the good recovery of the muon signal for each primary included in the analysis, also the exponent can be obtained with accuracy of less than 1% for the studied system. Detailed simulations show a dependence of the exponent on hadronic interaction properties, thus the determination of this parameter is important for understanding the muon deficit problem

Examining the Fundamental Elements of Physical and Health-Enhancing Educational Activity of Student in Distance Learning

This study illustrates the notion of physical and health-enhancing educational activity in distance learning processes as a particular kind of helpful activity on understanding the physical and health-enhancing knowledge. Based on analysing the psychological and pedagogical literature, 4 structural elements of student youth's physical and health-enhancing educational activity have been designated following distance learning processes: reϔ e iveǦsubjectiveǡ target, motivational, as well as activity-creative elements. Based on the data obtained, the motivational element indicates the motives system prompting them to physical education (PE) and makes the necessary for such classes in circumstances of remote education over the course of quarantine. The target element indicates goal setting, its details, and tasks intended to master the system of physical culture and health-enhancing knowledge, abilities, and skills. The activity-creative element reveals the system of skills as a collection of techniques to carry out physical activities at home, applying digital didactic materials. Moreover, the reϔ e iveǦsubjective element demonstrates the capacity of students to handle their internal world, obey healthy lifestyle rules, especially during quarantine, develop emotional maturity, get the most out of their potential, invoke a sense of concentration, se fǦconϔidenceǡ strength, movement

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO