Iron metallurgy of the Xianbei period in Tuva (Southern Siberia)

We present results of the complex investigation of large-scale iron production at the site of Katylyg 5 (Tuva, Southern Siberia) dating to 3rd-4th c. AD. The excavations have uncovered nine trapezoid underground smelting furnaces, a tonne of smelting slag, smithing remains and a charcoal production zone. The investigation of slag by Optical microscopy, SEM-EDS and ICP-MS confirms the performance of smelting and smithing operations at the site, and also suggests that the smelted ore was magnetite, associated with quartz. The presence of copper (bronze) prills in most of the smithing slag indicates that copper was worked alongside iron in the smithing hearths. The spatial division of the site into three different production zones (smelting, smithing and charcoalproduction) suggests a well-organized and self-sufficient industry, that was probably tightly controlled throughout all stages of the chaîne op´eratoire. The trapezoid furnaces identified at Katylyg, are also known from Cis-Baikal region where they date from the end of the 1st millennium BCE and throughout most of the 1st millennium AD. This suggests that the technology of trapezoid furnaces, along with the Kokel culture to which they are attributed, likely emerged in Tuva with the migrations from the Baikal region due to the westward Xianbei expansion during 1st-3rd c. AD

ИССЛЕДОВАНИЕ ШИРОКОПОЛОСНОЙ ГИДРОАКУСТИЧЕСКОЙ СИСТЕМЫ, СОДЕРЖАЩЕЙ ПРЕОБРАЗОВАТЕЛИ ВОЛНОВОДНОГО ТИПА

The results of experimental research of models of antennas hydroacoustic system (HAS), containing transducers of the waveguide type (TWT), which represent a coaxial set of identical water-filled piezocylinders, electrically excited by the principle of a traveling wave formation in the inner cavity of the TWT, are given. Possibilities of the TWT are analyzed when they are excited in accordance with the solution of the synthesis problem for the investigated HAS. The realization of such excitation is carried out by means of software-controlled multichannel blocks and allows providing a close to uniform amplitude-frequency characteristic of radiation and linear phase-frequency characteristic of radiation in a 3-octave frequency band. The possibility of radiation in this band of ultrashort pulses, tunable in frequency, as well as the formation of signals similar to the signals of cetaceans, is shown. The influence of the number of active piezocylinders of the TWT and the character of its electric excitation on the frequency and impulse response of the investigated HAS is considered. Directional properties of models of antennas HAS, including scanning and pulse operation modes, are considered. A comparative evaluation of the calculated and experimental data, as well as an evaluation of the efficiency of the TWT radiation, is given.Представлены результаты экспериментальных исследований макетов антенн гидроакустической системы (ГАС), содержащей преобразователи волноводного типа (ПВТ), которые представляют собой соосный набор идентичных водозаполненных пьезоцилиндров, электрически возбуждаемых в режиме формирования бегущей волны во внутренней полости ПВТ. Для исследуемой ГАС проанализированы возможности ПВТ при их возбуждении согласно решению задачи синтеза. Возбуждение ПВТ, осуществляемое программно-управляемыми многоканальными блоками, обеспечивает близкую к равномерной амплитудно-частотную и практически линейную фазочастотную характеристики излучения в полосе пропускания порядка трех октав. Показана возможность излучения в указанной полосе частот перестраиваемых по частоте ультракоротких импульсов, а также формирования сигналов, подобных сигналам китообразных. Проанализировано влияние числа пьезоцилиндров, входящих в состав ПВТ, и характера их возбуждения на частотные и импульсные характеристики макетов антенн исследуемой ГАС. Исследованы характеристики направленности макетов антенн, составленных из ПВТ, в том числе в режиме сканирования характеристики направленности. Выполнена сравнительная оценка расчетных и экспериментальных данных, а также оценка эффективности излучения ПВТ

Organizando um processo de treinamento de aula de futebol escolar para crianças do ensino fundamental

The relevance of the problem under research is determined by the fact that the modern physical education of children of elementary school age requires an efficiency improvement. The schools’ physical education curriculum is aimed at utilization of general forms of physical activity during the day (such as morning gymnastics, athletic pauses, therapeutic exercise, walks, etc.), but the substantial content of these forms of physical activity does not allow for full accounting of the abilities of children of this age group and does not facilitate the efficient development of most physical qualities. The purpose of this article is to elaborate a method to improve football techniques by developing the selected fundamental elements. This article presents a special set of exercises for young football players to help them master the techniques for faster and finer results in less time. The proposed exercises for training process were aimed at perfecting of fundamental technical actions of football players: individual – shots on target, dribbling; and team actions – passing the ball on the run. The materials of this article may be found useful by physical education students, physical education teachers of general schools, secondary and higher educational institutions, as well as by teacher of vocational education.  La relevancia del problema bajo investigación viene determinada por el hecho de que la educación física moderna de los niños en edad escolar primaria requiere una mejora de la eficiencia. El plan de estudios de educación física de las escuelas está dirigido a la utilización de formas generales de actividad física durante el día (como gimnasia matutina, pausas deportivas, ejercicio terapéutico, caminatas, etc.), pero el contenido sustancial de estas formas de actividad física no permite para la contabilidad completa de las habilidades de los niños de este grupo de edad y no facilita el desarrollo eficiente de la mayoría de las cualidades físicas. El propósito de este artículo es elaborar un método para mejorar las técnicas del fútbol desarrollando los elementos fundamentales seleccionados. Este artículo presenta un conjunto especial de ejercicios para jóvenes futbolistas que les ayudarán a dominar las técnicas para obtener resultados más rápidos y precisos en menos tiempo. Los ejercicios propuestos para el proceso de entrenamiento tenían como objetivo perfeccionar las acciones técnicas fundamentales de los futbolistas: individual - tiros a puerta, regate; y acciones del equipo: pasar el balón en la carrera. Los materiales de este artículo pueden resultar útiles para estudiantes de educación física, profesores de educación física de escuelas generales, instituciones de educación secundaria y superior, así como para profesores de educación profesional.A relevância do problema em estudo é determinada pelo fato de que a educação física moderna de crianças em idade escolar exige uma melhoria de eficiência. O currículo de educação física das escolas visa a utilização de formas gerais de atividade física durante o dia (como ginástica matinal, pausas atléticas, exercícios terapêuticos, caminhadas, etc.), mas o conteúdo substancial dessas formas de atividade física não permite para a plena contabilização das habilidades das crianças dessa faixa etária e não facilita o desenvolvimento eficiente da maioria das qualidades físicas. O objetivo deste artigo é elaborar um método para aprimorar as técnicas do futebol, desenvolvendo os elementos fundamentais selecionados. Este artigo apresenta um conjunto especial de exercícios para jovens jogadores de futebol para ajudá-los a dominar as técnicas para obter resultados mais rápidos e precisos em menos tempo. Os exercícios propostos para o processo de treinamento visavam ao aperfeiçoamento das ações técnicas fundamentais dos jogadores de futebol: individual - chutes a gol, dribles; e ações da equipe - passar a bola na corrida. Os materiais deste artigo podem ser considerados úteis por alunos de educação física, professores de educação física de escolas gerais, instituições de ensino médio e superior, bem como por professores de educação profissional

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

RESEARCH OF WIDEBAND HYDRO ACOUSTIC SYSTEM, CONTAINING TRANSDUCERS OF WAVEGUIDE TYPE

The results of experimental research of models of antennas hydroacoustic system (HAS), containing transducers of the waveguide type (TWT), which represent a coaxial set of identical water-filled piezocylinders, electrically excited by the principle of a traveling wave formation in the inner cavity of the TWT, are given. Possibilities of the TWT are analyzed when they are excited in accordance with the solution of the synthesis problem for the investigated HAS. The realization of such excitation is carried out by means of software-controlled multichannel blocks and allows providing a close to uniform amplitude-frequency characteristic of radiation and linear phase-frequency characteristic of radiation in a 3-octave frequency band. The possibility of radiation in this band of ultrashort pulses, tunable in frequency, as well as the formation of signals similar to the signals of cetaceans, is shown. The influence of the number of active piezocylinders of the TWT and the character of its electric excitation on the frequency and impulse response of the investigated HAS is considered. Directional properties of models of antennas HAS, including scanning and pulse operation modes, are considered. A comparative evaluation of the calculated and experimental data, as well as an evaluation of the efficiency of the TWT radiation, is given

The Formation of Composite Ti-Al-N Coatings Using Filtered Vacuum Arc Deposition with Separate Cathodes

Ti-Al-N coatings were deposited on high-speed steel substrates by filtered vacuum arc deposition (FVAD) during evaporation of aluminum and titanium cathodes. Distribution of elements, phase composition, and mechanical properties of Ti-Al-N coatings were investigated using Auger electron spectroscopy (AES), X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindentation, respectively. Additionally, tribological tests and scratch tests of the coatings were performed. The stoichiometry of the coating changes from Ti0.6Al0.4N to Ti0.48Al0.52N with increasing aluminum arc current from 70 A to 90 A, respectively. XRD and TEM showed only face-centered cubic Ti-Al-N phase with preferred orientation of the crystallites in (220) direction with respect to the sample normal and without precipitates of AlN or intermetallics inside the coatings. Incorporation of Al into the TiN lattice caused shifting of the (220) reflex to a higher 2θ angle with increasing Al content. Low content and size of microdroplets were obtained using coaxial plasma filters, which provides good mechanical and tribological properties of the coatings. The highest value of microhardness (36 GPa) and the best wear-resistance were achieved for the coating with higher Al content, thus for Ti0.48Al0.52N. These coatings exhibit good adhesive properties up to 30 N load in the scratch tests

Water dynamics in bulk and dispersed in silica CaCl2 hydrates studied by neutron scattering methods

International audienc

Phase relations of arsenian pyrite and arsenopyrite

Arsenian pyrite containing above 1 wt% As plays a crucial role in deposition and deportment of Au and other chalcophile elements. The importance of arsenian pyrite led to theoretical and experimental studies that examined properties and genesis of the mineral; however, the interpretation of the phase relations between arsenian pyrite and arsenopyrite is conflicting. In this contribution, we present the results of a review of the experimental studies that have investigated the crystallisation of pyrite in As-bearing systems, a summary of As content in pyrite coexisting with arsenopyrite in 37 deposits and the composition of arsenian pyrite in deposits with little or no arsenopyrite. The review demonstrates that the previous experimental studies that attempted to achieve equilibrium between pyrite and arsenopyrite observed from <1 to 4.7 wt% As in pyrite. The literature survey of the assemblages of pyrite and arsenopyrite shows that pyrite crystallising together with arsenopyrite commonly has a very heterogeneous composition with As content varying from below detection to about 10 wt% As and no clear discontinuities were observed across this range. In the deposits without arsenopyrite, arsenic content in pyrite can reach 20 wt% As. We consider three principal scenarios of the relations of arsenian pyrite and arsenopyrite: (A) Pyrite with high As content is stable in equilibrium with arsenopyrite. Low-As pyrite coexisting with arsenopyrite is a product of disequilibrium crystallisation; (B) a scenario of control of As content in pyrite coexisting with arsenopyrite by thermodynamic parameters including temperature, pressure, the activity of components and fluid composition and (C) a scenario where arsenian pyrite is a metastable mineral. The observations are inconsistent with a model of 5–6 wt% As in pyrite coexisting with arsenopyrite in equilibrium (scenario A). The stability range of the assemblage of pyrite and arsenopyrite constrains the thermodynamic control on the composition of pyrite crystallising in equilibrium with arsenopyrite (scenario B). The scenario of metastable crystallisation of arsenian pyrite (C) proposes formation of the mineral by fast growth from oversaturated fluids with As content controlled by surface adsorption and can explain such features as sector zoning of the mineral and the apparent negative temperature dependence of the solubility. The data phase relations of arsenian pyrite highlight the need for new experimental studies, and suggest that the scenario of disequilibrium phase relations of arsenian pyrite should be considered for interpretation of natural assemblages