157 research outputs found

    The Origin of Christian Charity

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    AbstractThe article considers the origin of Christian charity, its sources and principles, and also anсient civilization's influence on its development. Charity genesis as a sociocultural phenomenon has for a long time been of interest to philosophers, historians and scholars in other areas of the humanities. Already in ancient times such authors as Ennius, Cicero, and Seneca studied motivation, forms of blessings and restriction in this sphere, and also the typology of philanthropists. However, charity transformed due to change of eras, moral systems, level of civilization and socioeconomic development. Even during the ancient era two stages in charity development are examined: Greco-Roman, pagan and Christian. Studying the emergence of Christian charity, an analysis of its sources and interrelation with Roman imperial society are also the aim of this article

    The registration and the processing of signals of geomagnetic pulsations in the system of the geodynamic monitoring

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    Annotation: In this paper, methods of the implementing filtering are considered for recording of irregular disturbances of the geomagnetic field. The solution of problems of the processing of signals is considered for the system of the geodynamic control. They are based on the detection of the informative area of the registration in real time and the localization of the spatial location of the source of geomagnetic disturbances on the base of the regression analysis. It is noted that methods of simultaneous formation of borders of the bands of HPF and LPF necessary to use with the technical implementation of multi-band filtering. It allows to obtain the absolutely exact conjugation of frequency borders of neighboring subbands of filter, and also to reduce the number of tunable passive elements. Determined that in the technical implementation of the approach, obtaining an arbitrary phase-frequency characteristic that is not related to the amplitude-frequency response, and ensuring the stability of a multi-band filter of high order is important. Application of the regression analysis for selection and an assessment of parameters of distribution of geomagnetic pulsations at magnetotelluric sounding give the chance to consider features of use in system of monitoring of multirange filters and algorithms of spectral timing analysis.Keywords: geomagnetic field, disturbance, registration, processing, signal, geodynamic, monitoring, magnetotelluri

    RGB color camera for dynamical measurements of high temperature distribution on a surface of the heated solid

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    In this report we describe a fast 3-color method of the measurement of temperature distributions on a surface of a heated solid using a RGB color camera with a high frame rate (100 images per second). Statistical error the RGB method is not high, and do not exceed around 5.5 % which is surprising taking in to account the number of the measurements at each pixel. Comparison of the results of the temperature measurements on a tungsten plate heated by infra-red laser radiation and conducted with this technique and those obtained with the acousto-optical tunable filter technique demonstrate that error of the temperature measured by 3-color method is only two times as high as that of the tandem acousto-optic filter technique method.This work was performed using the Unique Scientific Instrument 'Laser heating at diamond anvil cell'[http://ckp-rf.ru/usu/507563/]

    Delamination of carbon-fiber strengthening layer from concrete beam during deformation (infrared thermography)

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    Technology of strengthening reinforced concrete structures with composite materials has found wide application. The effectiveness of strengthening of concrete structures with externally bonded reinforcement is supported by a great deal of experimental evidence. However, the problem of serviceability of such structures has not been adequately explored. The present work describes the results of experimental studies on the loadcarrying capacity of concrete beams strengthened with carbon fiber reinforced plastic (CFRP). Special emphasis is placed on studying the debonding of the strengthening layer from the concrete surface and analyzing its influence on the load-carrying capacity of beams. Infrared thermography is used to detect the first signs of debonding and to assess the debond growth rate

    Formation of the Electric Field Distribution in Thin Electro-Optic Layers for Precision Correction their Optical Characteristics

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    A method of making given field distribution within thin electro-optical layers by using narrow band electrodes placed at the same electric potential. A formula for electric field intensity produced by a single band electrode is obtained. Electric field modeling for different band electrode configurations is undertaken. It was shown, by applying piezoresponse force microscopy, that in case of highly inhomogeneous field the polarization of lithium niobate electro-optical film persisted only in the area above the band electrode. Lithium niobate, electro-optical structures, piezoresponse force microscopy, Computer simulation

    Process of cracking in reinforced concrete beams (simulation and experiment)

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    The paper presents the results of experimental and theoretical investigations of the mechanisms of crack formation in reinforced concrete beams subjected to quasi-static bending. The boundary-value problem has been formulated in the framework of brittle fracture mechanics and solved using the finite-element method. Numerical simulation of the vibrations of an uncracked beam and a beam with cracks of different size serves to determine the pattern of changes in the spectrum of eigenfrequencies observed during crack evolution. A series of sequential quasi-static 4-point bend tests leading to the formation of cracks in a reinforced concrete beam were performed. At each loading step, the beam was subjected to an impulse load to induce vibrations. Two stages of cracking were detected. During the first stage the nonconservative process of deformation begins to develope, but has not visible signs. The second stage is an active cracking, which is marked by a sharp change in eingenfrequencies. The boundary of a transition from one stage to another is well registered. The vibration behavior was examined for the ordinary concrete beams and the beams strengthened with a carbon-fiber polymer. The obtained results show that the vibrodiagnostic approach is an effective tool for monitoring crack formation and assessing the quality of measures aimed at strengthening concrete structures

    Traumatic vessel injuries initiating hemostasis generate high shear conditions

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    Blood flow is a major regulator of hemostasis and arterial thrombosis. The current view is that low and intermediate flows occur in intact healthy vessels, whereas high shear levels (>2000 s−1) are reached in stenosed arteries, notably during thrombosis. To date, the shear rates occurring at the edge of a lesion in an otherwise healthy vessel are nevertheless unknown. The aim of this work was to measure the shear rates prevailing in wounds in a context relevant to hemostasis. Three models of vessel puncture and transection were developed and characterized for a study that was implemented in mice and humans. Doppler probe measurements supplemented by a computational model revealed that shear rates at the edge of a wound reached high values, with medians of 22 000 s−1, 25 000 s−1, and 7000 s−1 after puncture of the murine carotid artery, aorta, or saphenous vein, respectively. Similar shear levels were observed after transection of the mouse spermatic artery. These results were confirmed in a human venous puncture model, where shear rates in a catheter implanted in the cubital vein reached 2000 to 27 000 s−1. In all models, the high shear conditions were accompanied by elevated levels of elongational flow exceeding 1000 s−1. In the puncture model, the shear rates decreased steeply with increasing injury size. This phenomenon could be explained by the low hydrodynamic resistance of the injuries as compared with that of the downstream vessel network. These findings show that high shear rates (>3000 s−1) are relevant to hemostasis and not exclusive to arterial thrombosis

    Magnetic fields in cosmic particle acceleration sources

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    We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play an important role in magnetic field evolution in the objects. We discuss a number of CR-driven, magnetic field amplification processes that are likely to operate when diffusive shock acceleration (DSA) becomes efficient and nonlinear. The turbulent magnetic fields produced by these processes determine the maximum energies of accelerated particles and result in specific features in the observed photon radiation of the sources. Equally important, magnetic field amplification by the CR currents and pressure anisotropies may affect the shocked gas temperatures and compression, both in the shock precursor and in the downstream flow, if the shock is an efficient CR accelerator. Strong fluctuations of the magnetic field on scales above the radiation formation length in the shock vicinity result in intermittent structures observable in synchrotron emission images. Resonant and non-resonant CR streaming instabilities in the shock precursor can generate mesoscale magnetic fields with scale-sizes comparable to supernova remnants and even superbubbles. This opens the possibility that magnetic fields in the earliest galaxies were produced by the first generation Population III supernova remnants and by clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review

    Supporting quadric method for collimated beams

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    В статье рассматривается задача расчета преломляющего элемента с двумя поверхностями, формирующего плоский фронт и заданное распределение освещенности. Формулируется метод согласованных квадрик для расчета данного оптического элемента, и показывается, что данный метод совпадает с градиентным методом для некоторого функционала, связанного с задачей перемещения масс Монжа–Канторовича. Это дает возможность адаптивного выбора шага в методе согласованных квадрик. В конце статьи приводится расчетный пример. We consider the problem of calculating a refractive element with two surfaces, forming a flat front and a given distribution of illumination. The supporting quadrics method is formulated for calculating a given optical element and it is shown that this method coincides with the gradient method for some functional related to the problem of the Monge-Kantorovich mass transfer problem. This enables adaptive selection of the step in the supporting quadric method. At the end of the article a design example is given.Работа выполнена при поддержке Министерства науки и высшего образования в рамках выполнения работ по Государственному заданию ФНИЦ «Кристаллография и фотоника» РАН в части численной реализации алгоритма расчета, а также грантов РФФИ (№ 18-29-03067, 18-07-00982) в части формулировки метода согласованных квадрик и доказательства совпадения с градиентным методом для соответствующего функционала

    Synthesis and Nanoscale Characterization of LiNbO3 Thin Films Deposited on Al2O3 Substrate by RF Magnetron Sputtering under Electric Field

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    LiNbO3 thin films were deposited on Al2O3 substrates by RF-magnetron sputtering with in-situ electric field to study the self-polarization effect. The films have been characterized crystallographically by x-ray diffraction, and morphologically by atomic force microscopy. The films contain crystallites of LiNbO3 with preferable orientation [012] along the normal to the Al2O3 substrate surface (012). Piezoresponse force microscopy was used to study vertical and lateral polarization direction in LiNbO3 thin films. The analysis of the histograms of vertical piezoresponse images allowed to reveal self-polarization effect in films. The local piezoelectric hysteresis performed on the nanometer scale indicates switching behavior of polarization for LiNbO3 thin film
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