Deformation resistance and structure-forming processes of iron aluminides in hot rolling

We have developed simple mathematical models of mean equivalent stress dependence on temperature and strain for selected iron aluminides. Four similar melts with 16.5-19.2 wt.% of Al, 4 wt.% of Cr and with various contents of Ti and B were studied and compared. Flat specimens graded by thickness were hot rolled. Deformation resistance was calculated from the roll force values obtained using a laboratory mill Tandem. Postdynamic structure-forming processes of the tested aluminides, as well as their cracking susceptibility, were investigated by metallography. The differences in the deformation behavior and formability of the tested aluminides were described.Разработаны простые математические модели зависимости среднего эквивалентного напряжения от температуры и деформации для выбранных алюминидов железа. Были изучены и сравнены четыре одинаковые плавки, содержащие 16,5...19,2 вес.% Al, и 4 вес.% Сг и различное количество титана и бора. Плоские образцы, рассортированные по толщине, подвергались горячей прокатке. Сопротивление деформированию рассчитывали по величине усилия на валки, определенной с использованием лабораторного прокатного стана Тандем. Процессы структурообразования испытанных алюминидов после динамического воздействия и их склонность к трещинообразованию исследовали с использованием металлографии. Описаны наблюдавшиеся различия в поведении испытанных алюминидов при деформировании и в способности к формоизменению

Semantic disambiguation and contextualisation of social tags

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-28509-7_18This manuscript is an extended version of the paper ‘cTag: Semantic Contextualisation of Social Tags’, presented at the 6th International Workshop on Semantic Adaptive Social Web (SASWeb 2011).We present an algorithmic framework to accurately and efficiently identify the semantic meanings and contexts of social tags within a particular folksonomy. The framework is used for building contextualised tag-based user and item profiles. We also present its implementation in a system called cTag, with which we preliminary analyse semantic meanings and contexts of tags belonging to Delicious and MovieLens folksonomies. The analysis includes a comparison between semantic similarities obtained for pairs of tags in Delicious folksonomy, and their semantic distances in the whole Web, according to co-occurrence based metrics computed with results of a Web search engine.This work was supported by the Spanish Ministry of Science and Innovation (TIN2008-06566-C04-02), and Universidad Autónoma de Madrid (CCG10-UAM/TIC-5877

Hot-cracking of high-alloyed steels evaluated by wedge rolling test

We present a new methodology of determination of hot-cracking f metallic materials, which is based on laboratory application of the wedge rolling test and computer processing of the results obtained. The experiment was made with selected new types of high-alloyed free-cutting (ferritic and austenitic) steels. The initial specimens underwent an additional modification enabling easier development of cracks which consisted in milling out of the defined V-shaped notches on a side wall of a specimen. After taking specimens from the rolled material, we performed the metallographic analysis of microstructures by means of optical microscopy as well as a SEM analysis of the cracks. The resulting microstructure in the propagating crack vicinity was markedly influenced by this fracture. In the crack vicinity, a noticeable refinement of grains was observed due to the stress-induced recrystallization and occurrence of deformation zones that were pronounced by the rolled-out and stretched sulphides. As a rule, fractures were created by the ductile failure with visible pits, caused by tearing of sulphides from the material. Susceptibility of the studied steels to hot-cracking was evaluated and compared.Представлен новый метод определения горячих трещин в металлических материалах, основанный на лабораторной методике прокатки на клин и компьютерной обработке результатов. Эксперименты выполняли на отобранных высоколегированных автоматных (ферритных и аустенитных) сталях нового типа. В исходных образцах фрезеровали У-образные надрезы на их боковой стороне, что облегчало развитие трещин. После вырезки образцов из прокатанного материала выполняли металлографический анализ микроструктуры с помощью оптической микроскопии и анализ трещин с помощью сканирующей микроскопии. Разрушение в значительной мере влияло на микроструктуру, возникшую вблизи развивающейся трещины. Вблизи трещины наблюдалось заметное изменение зерен вследствие рекристаллизации, вызванной напряжениями, и появления зон деформирования, соответствующих прокатанным и вытянутым сульфидам. Как правило, разрушение возникало за счет пластического разрыва с видимыми ямками, вызванного отрывом сульфидов от материала. Оценивалась и сравнивалась склонность изучаемых сталей к образованию горячих трещин

Limits of minimal models and continuous orbifolds

The lambda=0 't Hooft limit of the 2d W_N minimal models is shown to be equivalent to the singlet sector of a free boson theory, thus paralleling exactly the structure of the free theory in the Klebanov-Polyakov proposal. In 2d, the singlet sector does not describe a consistent theory by itself since the corresponding partition function is not modular invariant. However, it can be interpreted as the untwisted sector of a continuous orbifold, and this point of view suggests that it can be made consistent by adding in the appropriate twisted sectors. We show that these twisted sectors account for the `light states' that were not included in the original 't Hooft limit. We also show that, for the Virasoro minimal models (N=2), the twisted sector of our orbifold agrees precisely with the limit theory of Runkel & Watts. In particular, this implies that our construction satisfies crossing symmetry.Comment: 33 pages; v2: minor improvements and references added, published versio

On "Dotsenko-Fateev" representation of the toric conformal blocks

We demonstrate that the recent ansatz of arXiv:1009.5553, inspired by the original remark due to R.Dijkgraaf and C.Vafa, reproduces the toric conformal blocks in the same sense that the spherical blocks are given by the integral representation of arXiv:1001.0563 with a peculiar choice of open integration contours for screening insertions. In other words, we provide some evidence that the toric conformal blocks are reproduced by appropriate beta-ensembles not only in the large-N limit, but also at finite N. The check is explicitly performed at the first two levels for the 1-point toric functions. Generalizations to higher genera are briefly discussed.Comment: 10 page

Clear Lake sediments: Anthropogenic changes in physical sedimentology and magnetic response

We analyzed the sedimentological characteristics and magnetic properties of cores from the three basins of Clear Lake, California, USA, to assess the depositional response to a series of land use changes that occurred in the watershed over the 20th century. Results indicate that distinct and abrupt shifts in particle size, magnetic concentration/mineralogy, and redox conditions occur concurrently with a variety of ecological and chemical changes in lake bed sediments. This coincidence of events occurred around 1927, a datum determined by an abrupt increase in total mercury (Hg) in Clear Lake cores and the known initiation of open-pit Hg mining at the Sulphur Bank Mercury Mine, confirmed by ²¹⁰Pb dating. Ages below the 1927 horizon were determined by accelerator mass spectrometry on ¹⁴C of coarse organic debris. Calculated sedimentation rates below the 1927 datum are ~1 mm/yr, whereas rates from 1927 to 2000 are up to an order of magnitude higher, with averages of ~3.5–19 mm/yr. In both the Oaks and Upper Arms, the post-1927 co-occurrence of abrupt shifts in magnetic signatures with color differences indicative of changing redox conditions is interpreted to reflect a more oxygenated diagenetic regime and rapid burial of sediment below the depth of sulfate diffusion. Post-1927 in the Oaks Arm, grain size exhibits a gradual coarsening-upward pattern that we attribute to the input of mechanically deposited waste rock related to open-pit mining activities at the mine. In contrast, grain size in the Upper Arm exhibits a gradational fining-upward after 1927 that we interpret as human-induced erosion of fine-grained soils and chemically weathered rocks of the Franciscan Assemblage by heavy earthmoving equipment associated with a road- and home-building boom, exacerbated by stream channel mining and wetlands destruction. The flux of fine-grained sediment into the Upper Arm increased the nutrient load to the lake, and that in turn catalyzed profuse cyanobacterial blooms through the 20th century. The resulting organic biomass, in combination with the increased inorganic sediment supply, contributed to the abrupt increase in sedimentation rate after 1927.KEYWORDS: Clear Lake, California, USA, particle size trends, ¹⁴C, paleolimnology, late Holocene, land use patterns, Sulphur Bank Mercury Mine, mercury, magnetic dissolutio

Challenges of beta-deformation

A brief review of problems, arising in the study of the beta-deformation, also known as "refinement", which appears as a central difficult element in a number of related modern subjects: beta \neq 1 is responsible for deviation from free fermions in 2d conformal theories, from symmetric omega-backgrounds with epsilon_2 = - epsilon_1 in instanton sums in 4d SYM theories, from eigenvalue matrix models to beta-ensembles, from HOMFLY to super-polynomials in Chern-Simons theory, from quantum groups to elliptic and hyperbolic algebras etc. The main attention is paid to the context of AGT relation and its possible generalizations.Comment: 20 page

European guidelines for quality assurance in colorectal cancer screening and diagnosis: overview and introduction to the full supplement publication

Population-based screening for early detection and treatment of colorectal cancer (CRC) and precursor lesions, using evidence-based methods, can be effective in populations with a significant burden of the disease provided the services are of high quality. Multidisciplinary, evidence-based guidelines for quality assurance in CRC screening and diagnosis have been developed by experts in a project co-financed by the European Union. The 450-page guidelines were published in book format by the European Commission in 2010. They include 10 chapters and over 250 recommendations, individually graded according to the strength of the recommendation and the supporting evidence. Adoption of the recommendations can improve and maintain the quality and effectiveness of an entire screening process, including identification and invitation of the target population, diagnosis and management of the disease and appropriate surveillance in people with detected lesions. To make the principles, recommendations and standards in the guidelines known to a wider professional and scientific community and to facilitate their use in the scientific literature, the original content is presented in journal format in an open-access Supplement of Endoscopy. The editors have prepared the present overview to inform readers of the comprehensive scope and content of the guidelines.Fil: Arrossi, Silvina. Centro de Estudios de Estado y Sociedad; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: von Karsa, Lawrence. International Agency for Research on Cancer; FranciaFil: Patrick, J.. NHS Cancer Screening Programmes Sheffield; Reino Unido. University of Oxford; Reino UnidoFil: Segnan, N.. International Agency for Research on Cancer; Francia. AO Città della Salute e della Scienza di Torino; ItaliaFil: Atkin, W.. Imperial College London; Reino UnidoFil: Halloran, S.. University of Surrey; Reino UnidoFil: Saito, H.. National Cancer Centre; JapónFil: Sauvaget, C.. International Agency for Research on Cancer; FranciaFil: Scharpantgen, A.. Ministry of Health; LuxemburgoFil: Schmiegel, W.. Ruhr-Universität Bochum; AlemaniaFil: Senore, C.. AO Città della Salute e della Scienza di Torino; ItaliaFil: Siddiqi, M.. Cancer Foundation of India; IndiaFil: Sighoko, D.. University of Chicago; Estados Unidos. Formerly International Agency for Research on Cancer; FranciaFil: Smith, R.. American Cancer Society; Estados UnidosFil: Smith S.. University Hospitals Coventry & Warwickshire NHS Trust; Reino UnidoFil: Suchanek, S.. Charles University; República ChecaFil: Suonio, E.. International Agency for Research on Cancer; FranciaFil: Tong, W.. Chinese Academy of Sciences; República de ChinaFil: Törnberg, S.. Stockholm Gotland Regional Cancer Centre. Department of Cancer Screening; SueciaFil: Van Cutsem, E.. Katholikie Universiteit Leuven; BélgicaFil: Vignatelli, L.. Agenzia Sanitaria e Sociale Regionale; ItaliaFil: Villain, P.. University of Oxford; Reino UnidoFil: Voti, L.. Formerly International Agency for Research on Cancer; Francia. University of Miami; Estados UnidosFil: Watanabe, H.. Niigata University; JapónFil: Watson, J.. University of Oxford; Reino UnidoFil: Winawer, S.. Memorial Sloan–Kettering Cancer Center; Estados UnidosFil: Young, G.. Flinders University. Gastrointestinal Services; AustraliaFil: Zaksas, V.. State Patient Fund; LituaniaFil: Zappa, M.. Cancer Prevention and Research Institute; ItaliaFil: Valori, R.. NHS Endoscopy; Reino Unid

The Bile Acid Synthesis Pathway Is Present and Functional in the Human Ovary

Background: Bile acids, end products of the pathway for cholesterol elimination, are required for dietary lipid and fat-soluble vitamin absorption and maintain the balance between cholesterol synthesis in the liver and cholesterol excretion. They are composed of a steroid structure and are primarily made in the liver by the oxidation of cholesterol. Cholesterol is also highly abundant in the human ovarian follicle, where it is used in the formation of the sex steroids. Methodology/Principal Findings: Here we describe for the first time evidence that all aspects of the bile acid synthesis pathway are present in the human ovarian follicle, including the enzymes in both the classical and alternative pathways, the nuclear receptors known to regulate the pathway, and the end product bile acids. Furthermore, we provide functional evidence that bile acids are produced by the human follicular granulosa cells in response to cholesterol presence in the culture media. Conclusions/Significance: These findings establish a novel pathway present in the human ovarian follicle that has the capacity to compete directly with sex steroid synthesis