3,496 research outputs found
Review of recent advances in local approaches applied to pre-stressed components under fatigue loading
Fatigue strength of mechanical components in the high cycle regime depends on both the applied loading and the intensity of any residual stress field induced by either non-homogeneous plastic deformation or the solidification of a local portion of material due to welding operations. In presence of geometric variations that are amenable to being modelled as a sharp V-notch, the residual stress distribution near the notch tip is singular and follows the same form as the solution obtained by Williams in 1952 where the intensity of the asymptotic stress field is quantified by the notch stress intensity factor (NSIF). However, the residual stress varies during fatigue loading and a stable value may be reached. Numerical models have been developed for the calculation of the residual NSIFs and their variation under fatigue loading. Taking advantage of these models, new local approaches have also been recently developed which are able to predict the fatigue strength of pre-stressed notched components. The present paper provides a brief review of such recent advances
Características físico-químicas de meis produzidos por espécies de meliponíneos.
Além da abelhas Africanizadas (Apis mellifera L.), as abelhas indígenas sem ferrão ou meliponíneos (Meliponinae) são potenciais produtoras de mel. Esse produto apresenta carcterísticas distintas do mel produzido pelas abelhas do gênero Apis, sendo muito apreciado pelos consumidores. Entretanto, são escassos os dados científicos a respeito da composição desse mel na literatura nacional e internacional. A proposta deste trabalho é avaliar as características físico-químicas do mel produzido por meliponíneos. As análises físico-químico foram realizadas de acordo com as técnicas descritas pela AOAC (Association of Official Analytical Chemists), e pela European Honey Comission, conforme recomendado pela CAC (Codex Alimentarius Comission). Os resultados obtidos reforçam a necessidade do desenvolvimento de um padrão próprio para os méis de abelhas sem ferrão, incluindo critérios microbiológicos.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010
Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)
In this paper we continue the release of high-level data products from the
multiyear photometric survey collected at the 67/92 cm Schmidt Telescope in
Asiago. The primary goal of the survey is to discover and to characterise
variable objects and exoplanetary transits in four fields containing five
nearby open clusters spanning a broad range of ages. This second paper releases
a photometric catalogue, in five photometric bands, of the Solar-age,
Solar-metallicity open cluster M 67 (NGC 2682). Proper motions are derived
comparing the positions observed in 2013 at the Asiago's Schmidt Telescope with
those extracted from [email protected] MPG/ESO images in 2000. We also analyse the
variable sources within M 67. We detected 68 variables, 43 of which are new
detection. Variable periods and proper-motion memberships of a large majority
of sources in our catalogue are improved with respect to previous releases. The
entire catalogue will be available in electronic format. Besides the general
interest on an improved catalogue, this work will be particularly useful
because of: (1) the imminent release of Kepler/K2 Campaign-5 data of this
cluster, for which our catalogue will provide an excellent, high spatial
resolution input list, and (2) characterisation of the M 67 stars which are
targets of intense HARPS and HARPS-N radial-velocity surveys for planet search.Comment: 8 pages, 6 figures (2 at low resolution), 2 tables. Accepted for
publication in MNRAS on October 17, 2015. Electronic materials available at
the url http://groups.dfa.unipd.it/ESPG/M67.html , and later on the Journal
and at the CD
TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b
We present four new light curves of transiting exoplanets WASP-1b and
HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing
variations of Exoplanets) project. We re-analyzed light curves from the
literature in a homogeneous way, calculating a refined ephemeris and
orbital-physical parameters for both objects. WASP-1b does not show any
significant Transit Timing Variation signal at the 120 s-level. As for
HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that
could be ascribed to the presence of a perturber or, more probably, to a
previously unnoticed high level of stellar activity. The rotational period of
HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with
its optical variability and strong emission of CaII H&K lines, is consistent
with a young stellar age (< 1 Gyr) and support the hypothesis that stellar
activity may be responsible of the measured deviations of the transit times.Comment: 7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichte
Cultivo agroecológico de plantas medicinais, aromáticas, condimentares e ornamentais.
bitstream/CPAP-2010/57349/1/FOL152.pd
Teor de óleo essencial de Ocimum selloi Benth. sob diferentes doses de compostos orgânicos.
Em espécies bioativas, a aplicação de compostos orgânicos tem sido relacionada à produção de metabólitos secundários. No presente estudo, avaliou-se o efeito de diferentes doses de compostos orgânicos no teor de óleo essencial de alfavaca anisada, fornecendo bases científicas para agricultura orgânica. Em Curitiba-PR, ano de 2008, num delineamento em blocos ao acaso, com três repetições, doses (0, 0,85, 1,7 e 3 t.ha-1) de compostos estabilizados (A, B, C e D), elaborados com diferentes materiais orgânicos, foram utilizadas no cultivo de alfavaca anisada. O espaçamento utilizado em cultivo protegido irrigado foi de 0,5m entre linhas por 1,0m entre plantas. Aos seis meses de cultivo, amostras compostas de folhas foram coletadas e submetidas ao processo de hidrodestilação, por meio do aparelho do tipo Clevenger, para quantificação do óleo essencial. Em solo com acúmulo de matéria orgânica as doses e compostos avaliados não influenciaram o teor de óleo essencial de Ocimum selloi Beth.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010
Ações da Embrapa Pantanal em plantas medicinais na região de Corumbá-MS.
bitstream/item/79992/1/ADM137.pdfFormato eletronico. Disponível também em: Capital do Pantanal, MS Noticias, ZooNews, Agora MS, Capital do Pantanal, BBC News, Jurídico Brasil.org.br, Agronline, Grupo Cultivar, Naviraí Notícias
Non-Uniform Planar Slicing for Robot-Based Additive Manufacturing
Planar slicing algorithms with constant layer thickness are widely implemented for geometry processing in Additive Manufacturing (AM). Since the build direction is fixed, a staircase effect is produced, decreasing the final surface finish. Also, support structures are required for overhanging portions. To overcome such limits, AM is combined with manipulators and working tables with multiple degrees of freedom. This is called Robot-Based Additive Manufacturing (RBAM) and it aims to increase the manufacturing flexibility of traditional printers, enabling the deposition of material in multiple directions. In particular, the deposition direction is changed at each layer requiring non-uniform thickness slicing. The total number of layers, as well as the volume of the support structures and the manufacturing time are reduced, while the surface finish and mechanical performance of the final product are increased. This paper presents an algorithm for non-uniform planar slicing developed in Rhinoceros and Grasshopper. It processes the input geometry and uses parameters to capture manufacturing limits. It mostly targets curved geometries to remove the need for support structures, also increasing the part quality
The low-energy limit of AdS(3)/CFT2 and its TBA
We investigate low-energy string excitations in AdS3 × S3 × T4. When the worldsheet is decompactified, the theory has gapless modes whose spectrum at low energies is determined by massless relativistic integrable S matrices of the type introduced by Al. B. Zamolodchikov. The S matrices are non-trivial only for excitations with identical worldsheet chirality, indicating that the low-energy theory is a CFT2. We construct a Thermodynamic Bethe Ansatz (TBA) for these excitations and show how the massless modes’ wrapping effects may be incorporated into the AdS3 spectral problem. Using the TBA and its associated Y-system, we determine the central charge of the low-energy CFT2 to be c = 6 from calculating the vacuum energy for antiperiodic fermions — with the vacuum energy being zero for periodic fermions in agreement with a supersymmetric theory — and find the energies of some excited states
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