On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Archive and refugia of soil organisms: Applying a pedodiversity framework for the conservation of biological and non-biological heritages

The pedosphere is a part of our natural heritage. Soils should be considered both for their biological and for their geological resources. During the Anthropocene, human activities have dramatically changed the land surface and remodified soil cover, resulting in many natural pedotaxa being at risk of extinction. Recently, biogeographers and ecologists recognized that numerous biotaxa should be considered as edaphic endemisms, and as a consequence, in situ soil preservation is important relative to both its biological and geological value. This contribution discusses the similarity and differences between biodiversity and pedodiversity and proposes using pedodiversity as a surrogate measure of above-ground biodiversity and an indicator of below-ground biodiversity. Another objective is to explore the relevance of soil diversity to soil ecology by illustrating how the analysis of pedotaxa and their genetic soil horizons can be applied in conservation biology. To preserve biological and geological heritage inherent to the pedosphere, we propose to design a network of soil reserves. The proposed network could also be an efficient way to preserve soil characteristics and qualities of undisturbed soils that would become benchmarks for soil monitoring programs. Synthesis and applications. The coincidence between patterns of biodiversity and pedodiversity offers a new and unexplored direction for understanding the genesis of biological and non-biological assemblages and the spatial patterns of soils and living organisms. Pedodiversity can be used as a practical surrogate indicator of soil diversity. We provide a pedodiversity framework for the design of a network of soil reserves for the preservation and monitoring of soil biodiversity. This new framework could contribute toward the development of a unified theory of natural diversity and to understanding the role of the pedosphere in the provision of ecosystem services. The coincidence between patterns of biodiversity and pedodiversity offers a new and unexplored direction for understanding the genesis of biological and non-biological assemblages and the spatial patterns of soils and living organisms. Pedodiversity can be used as a practical surrogate indicator of soil diversity. We provide a pedodiversity framework for the design of a network of soil reserves for the preservation and monitoring of soil biodiversity. This new framework could contribute toward the development of a unified theory of natural diversity and to understanding the role of the pedosphere in the provision of ecosystem services. © 2012 British Ecological Society.Peer Reviewe

Soil organic carbon sequestration according to two Geoset long-term field experiments in the Moscow region

The feasibility of implementing the "4 ppm" initiative, which assumes an annual increase in organic carbon stocks of agricultural soils in the layer 0-40 cm, was estimated with the dynamic carbon model RothC in two long-term DAOS experiments in the Moscow region, conducted in neighbouring fields for 74 and 76 years. Treatments included absolute control, application of organic, mineral, organic and mineral fertilizers at increasing rates. One of the experiments showed the growth of C stocks 12‰ in the layer 0-20 cm in the first 20 years in treatments with mineral fertilization, and 17‰ with the additional application of manure in an average annual rate of 10 Mg·ha-1. The accumulation of C allowed increasing its stock by 18-25%. Still, with the subsequent decline in crop rotation productivity, there was a loss of part of the previously accumulated C. In another experiment, at close values of annual C input, there was a loss of initial C stock due to the history of land use. The crop rotation adjustment provided a 3-8 ‰ increase of soil C in the 0-20 cm layer in the first 20 years after introduction but was insufficient to match the "4 ppm" initiative. In the long term, the organic fertilizer system had an advantage over the mineral one in ensuring the stability of organic C stocks in the arable layer. However, the management of C sequestration was complicated in the non-equilibrium state of the carbon system "plant residues-organic fertilizer-soil"

4TH International congress of the medieval archaeology of eurasian steppes

© 2020 Academy of Sciences of Tatarstan, A.Kh. Khalikov Archaeology Institute. All rights reserved. The publication features a brief summary and results of the 4th International Congress on the Medieval Archaeology of Eurasian Steppes held on September 16-21, 2019 in Ulan-Ude (the Republic of Buryatia). The congress agenda included 229 reports by scientists from various countries: Russia, Kazakhstan, France, Germany, Austria, Great Britain, Canada, Switzerland, Spain, Bulgaria, Hungary, Croatia, Ukraine, Turkey, Israel, India, Kyrgyzstan, China, Japan and Mongolia. The congress participants presented reports covering a wide range of issues related to the study of the cultural and historical space of the steppe zone of Eurasia. The congress included the opening of the exhibition "The Huns. Empire of the Steppes"(The Huns. Secrets of Lost Civilizations)

Caracterização etnopedológica de Planossolos utilizados em cerâmica artesanal no Agreste Paraibano Ethnopedological studies on solonetz and Planosols used in pottery craftwork in the Agreste region, State of Paraiba

Técnicas adaptadas da etnociência clássica foram utilizadas para descrever e avaliar os conhecimentos de um grupo de artesãos camponeses do Agreste Paraibano sobre alguns solos que eles usam como recurso cerâmico. Cinco perfis de solo foram descritos por agrônomos-pesquisadores (abordagem eticista) e por camponeses (abordagem emicista), em locais onde a população local extrai material para cerâmica. Amostras coletadas em ambas as abordagens foram usadas para caracterização morfológica e analítica desses solos. Os camponeses pesquisados foram capazes de distinguir, identificar e nomear diversos materiais de solo, arranjados em estratos ao longo dos perfis de solo, de modo comparável ao arranjo dos horizontes pedogenéticos. A visão, o tato e o paladar foram empregados pelos artesãos na avaliação da qualidade do solo para cerâmica. Quatro perfis descritos junto às fontes de material cerâmico foram classificados como Planossolo Nátrico e um como Planossolo Háplico. A realização de pesquisas etnopedológicas em diferentes contextos sociais e pedológicos pode contribuir para o avanço da ciência do solo, sendo também uma oportunidade para melhor compreender as formas camponesas de conhecimento e manejo de solos.<br>Classic ethnoscientific techniques were adapted to describe and analyze the knowledge of peasant potters about soils they use for making pottery in a rural village in the Agreste region, State of Paraiba, northeastern Brazil. Five soil profiles from pits where local people obtain pottery clay were formally described by researchers (etic approach) and by peasant artisans (emic approach). Samples collected during both the emic and etic approaches were used for the morphological and analytical soil characterization. The peasant potters were able to distinguish, identify, and name soil materials arranged in layers along the soil profiles, somehow comparable to the arrangement of the pedogenetic horizons. Vision, touch and taste are used by local potters to evaluate the quality of pottery clay. Among the soil profiles described near clay pits, four were classified as Haplic Solonetz, and one as Eutric Planosol, according to the FAO/UNESCO legend. Ethnopedological studies in different social and pedological environments could contribute to the advancement of soil science and are an opportunity for an improvement in the understanding and appreciation of soil knowledge and management by peasant potters