353 research outputs found
Global Fatigue Life Modelling of Steel Half-pipes Bolted Connections
No full textAbstractA steel hybrid structural solution for onshore wind turbine towers was proposed in the European project SHOWTIME. This solution is used in the lattice structure for the lower portion of the tower. Recently, a procedure for fatigue life estimation of steel half-pipes bolted connections applied in global structural models using multiaxial Smith-Watson-Topper (SWT) criteria was proposed by Öztürk et al. In this paper a procedure for design S-N curve modelling of steel half-pipes bolted connections is proposed. This procedure is based on a local approach using multiaxial fatigue criteria together with an elastoplastic analysis using the finite element method. The materials to be used in this analysis are the S355 and S690 steels. This evaluation to be performed is calibrated with experimental results of fatigue tests of the connection under consideration
The oldest brachiopods from the lower Cambrian of South Australia
No full textThe morphology and organophosphatic shell structure of the paterinate brachiopod Askepasma is documented using new and previously collected specimens from the lower Cambrian of South Australia. Lack of adequately preserved material has seen the majority of paterinate specimens previously reported from South Australia referred to the genus Askepasma and treated under open nomenclature. Large collections of paterinates from the lower Cambrian Wilkawillina, Ajax, and Wirrapowie limestones in the Arrowie Basin, South Australia have prompted redescription of the type species Askepasma toddense and the erection of a new species, Askepasma saproconcha sp. nov. Askepasma saproconcha sp. nov. currently represents the oldest known brachiopod from the lower Cambrian successions in South Australia with a FAD in pre-trilobitic (Terreneuvian, Cambrian Stage 2, lower Atdabanian) strata in the basal part of the Wilkawillina and Wirrapowie limestones. Askepasma toddense predominantly occurs in Abadiella huoi Zone equivalent strata (Unnamed Cambrian Series 2, Stage 3, middle-upper Atdabanian) in the upper part of the lower Wilkawillina, Wirrapowie and Ajax limestones. The shell microstructure of Askepasma suggests a proximal stem group position within the Brachiopoda and similarities with tommotiid taxa provides further evidence that the ancestry of crown group brachiopods is firmly entrenched within the Tommotiida
[CODE] epfl-dias/llvm-project: PelagoLLVM-14.0.0
No full textThe LLVM Project is a collection of modular and reusable compiler and toolchain technologies.Chris Lattner, Craig Topper, Simon Pilgrim, Rafael Ávila de Espíndola, Matt Arsenault, Sanjay Patel, Ted Kremenek, Daniel Dunbar, Doug Gregor, Benjamin Kramer, Fangrui Song, Rui Ueyama, Richard Smith, Chandler Carruth, Nikita Popov, Nico Weber, Bill Wendling, Eric Christopher, David Blaikie, … Tobias Grosser. (2023). epfl-dias/llvm-project: PelagoLLVM-14.0.0 (llvmorg-14.0.0). Zenodo. https://doi.org/10.5281/zenodo.839196
Intervenciones afectivas al archivo materno en "La caja Topper" de Nicolás Gadano
No full textThrough the study of the autobiographical novel La caja Topper by Nicolás Gadano (2019), this article addresses the uses of the archive in the narratives of the children of victims ––in a broad sense–– of the last Argentine military dictatorship. Following the theoretical propositions of Jacques Derrida, Sara Ahmed, and Adriana Cavarero, we analyze the interventions that Gadano makes on the objects that his mother kept in a sneaker box as memorabilia of the family exile experience. First, we study the way in which the old box and the objects contained in it function as a matriarchive. Second, we analyze the operations that Gadano performs on the materiality, content, and ordering of the objects in the box, which produces a generational transfer of authority over the archive. Finally, we conclude that, through his fidelity to the maternal affective style, the author disassembles the traditional model of emotional labor division, reshaping the links between gender, generations, and memory.Com base no estudo do romance autobiográfico La caja Topper de Nicolás Gadano (2019), este artigo aborda os usos do arquivo nas narrativas dos filhos das vítimas da última ditadura militar argentina. Partindo das proposições teóricas de Jacques Derrida, Sara Ahmed e Adriana Cavarero, são analisadas as intervenções que, por meio da escrita do livro, Gadano faz sobre os objetos pertencentes à experiência familiar do exílio, que a mãe guardava em uma caixa de tênis. Em primeiro lugar, é estudado como a velha caixa e os objetos nela contidos funcionam como um matriarquivo. Em segundo lugar, são analisadas as operações que o livro realiza sobre a materialidade, o conteúdo e a ordenação dos objetos na caixa, para produzir uma transferência geracional da autoridade sobre o arquivo. Finalmente, conclui-se que, com sua fidelidade ao estilo afetivo materno, La caja Topperproduz uma desarticulação do modelo tradicional da divisão do trabalho emocional, que reconfigura os vínculos entre gênero, gerações e memória.A partir del estudio de la novela autobiográfica La caja Topper (2019) de Nicolás Gadano, este artículo aborda los usos del archivo en las narrativas de hijos de víctimas —en sentido amplio— de la última dictadura militar argentina. Desde las proposiciones teóricas de Jacques Derrida, Sara Ahmed y Adriana Cavarero se analizan las intervenciones realizadas por Gadano sobre los objetos pertenecientes a la experiencia familiar del exilio resguardados por la madre en una caja de zapatillas. En primer lugar, se estudia el modo en que la antigua caja y los objetos allí contenidos funcionan como un matriarchivo. En segundo lugar, se analizan las operaciones que Gadano realiza sobre la materialidad, el contenido y el ordenamiento de los objetos de la caja, para realizar un traspaso generacional de la autoridad sobre el archivo. Finalmente, se concluye que, con su fidelidad al estilo afectivo materno, el autor produce una desarticulación del modelo tradicional de la división del trabajo emocional, que reconfigura vínculos entre género, generaciones y memoria
Mean Stress Effect in Stress-Life for Hard Steels
No full textThe work in this thesis examines the effect of mean stress on the fatigue behaviour of very hard (Rockwell C 60) steels (AISI 8822, 8620, 9310, and cold-worked pre-stressing wire). In the mean stress tests, the minimum stress in the fatigue cycle was varied from test to test over a range from -1200 MPa to a value approaching the true fracture stress of each material. The results are not adequately explained by current theories for the effect of mean stress on fatigue behaviour in the region of compressive mean stresses. All current theories suggest that the maximum stress at the fatigue limit decreases with decreasing minimum stress. The results of this study shows that instead of continuing to decrease with decreasing minimum stress the maximum stress at the fatigue limit remains constant indicating an insensitivity to the minimum stress in the fatigue cycle for minimum stresses below the value in a fully reversed fatigue test. The theory proposed by the author corrects this error by maintaining the maximum stress at the fatigue limit constant with decreasing minimum stress in the region of negative mean stresses. The results are of interest to designers of components in which high negative residual stresses are introduced into materials hardened by, for example, carburizing, nitriding, or induction hardening to improve the fatigue strength of components. The present work allows considerably higher design stresses for operating stresses in the negative mean stress region than previous theories permit
Francis Douce and His Collection: An Antiquarian in Great Britain, 1957-1834
No full textThis paper is a study of the English antiquarian Francis Douce and his collection of books, prints, drawings, coins, and artifacts. The major theme of the collection - the manners, beliefs, and customs of the world - is connected to three of Douce's most remarkable collecting interests: children's books and games; fools and jesters; and the sublime, including his collections of death, demonology, and witchcraft. The collection, divided between the Bodleian Library and the Ashmolean Museum at Oxford, remains an invaluable resource for scholars in a wide variety of fields. It is hoped that this paper will emphasize the vision according to which Douce developed a distinctive collection; that it will shed additional light on British collecting and collectors of Douce's lifetime, 1757-1834; and that it will serve as a lesson in collecting that might be used by librarians and non-librarians alike
Beet Puller and Topper.
No full textPatent for a new machine to pull beets from the ground as moving chains cut off the leaves and deposit the beets into a bend
Aerodynamic Shaping of a Propulsive Fuselage Concept: A Design Space Exploration
No full textBoundary layer ingestion is an airframe-propulsion integration technology capable of enhancing aircraft propulsive efficiency. The Propulsive Fuselage Concept, a tube-and-wing layout with an rear-fuselage-mounted propulsor in the boundary layer ingestion configuration, especially takes advantage this. However, the relation between physical shape and aerodynamic performance, resulting from the complex airframe-propulsor interaction, is not entirely understood. Also, contrary to long-haul aircraft, few studies have investigated the application of the concept on medium-haul aircraft with only 10% cruise thrust contribution coming from the boundary layer ingestion propulsor, which is a top-level requirement of the APPU project. To facilitate parametric studies regarding these research gaps, a parametric model is developed and implemented in an engineering design application that automates aerodynamic analysis to high degree. This thesis presents a methodology to numerically analyze axisymmetric propulsive fuselage concept designs; an engineering design application using the knowledge based engineering technology is presented that facilitates the implementation of complex engineering design rules in the construction of the parametric model. The application consist of three components. Firstly, a flexible geometric parameterization in 2D is developed that is proven capable of constructing well-performing designs. A translation mechanism is developed between these geometric input parameters and input parameters for class shape transformation curves, which form the mathematical basis for the geometry. Secondly, the construction of a C-shaped domain and a multi-block structured mesh are also automated in the application. The mesh density for this application was verified through a mesh convergence study, and can be adjusted to fit other mesh requirements through various mesh control capabilities. Lastly, the scripted interaction between the application and ANSYS Fluent software is automated. A fan modeling methodology was developed using boundary conditions that requires only fan pressure ratio as input, while mass flow continuity through the fan is ensured. The meshing and simulation routines are validated by comparing the results of the presented routine to that of a status-quo numerical simulation. All relevant aerodynamic output parameters show agreement in a range of 3.3%.The working of the engineering design application is demonstrated in a design space exploration based on the hypothesis that increased conicity of the rear fuselage and nacelle shape with respect to the longitudinal axis can reduce the required fan power in cruise conditions. To isolate the effect of conicity, a parameter sweep was conducted. Results show that with increasing conicity, the overall viscous dissipation was continuously reduced. Also the total pressure recovery at the fan inlet face increases up to a nacelle conical angle of 11 degrees, after which this decays due to increased wetted area. At 11 degrees conicity, the aerodynamic efficiency (defined as fan power required for a given net propulsive force) was increased by 0.81% relative to a less conical status-quo baseline design with 6 degrees conicity. The increased fuselage volume and wetted area due to increased conicity introduced the opportunity to shorten the fuselage without decreasing fuselage volume. This increased aerodynamic efficiency by 1.65% relative to the baseline. Also, as the intake diffusion functionality was redundant in this flow field, a third design was constructed with a 29% shorter intake duct, which increased aerodynamic efficiency by 1.81% compared to the baseline. Demonstrated by these unoptimized designs and the observed physical mechanisms, it is concluded that aerodynamic efficiency could benefit from the direct and indirect effects of an increase in conicity of the propulsive fuselage concept.APPU ProjectAerospace Engineerin
Clovis Technology and Settlement in the American Southeast
No full textThis dissertation presents new data on Clovis site occupation, technological organization, and settlement in the American Southeast. Evidence suggests that traditionally-accepted, western-centric models do not fully explain Clovis technological characteristics and settlement patterns in the region.
My second chapter presents the results of a 40 square meter block excavation on the Topper site (SC) hillside where a buried Clovis assemblage has been recovered. I review the site geomorphology and formation processes to evaluate the context of the Clovis component, characterize the Clovis assemblage and the horizontal distribution of artifacts to understand how the Clovis occupants used this portion of the site, and compare these excavation results to the rest of the archaeological record at Topper to discuss the general nature of the Clovis occupation there. My third chapter focuses on the 174 bifaces from Topper to understand biface production. I present the process of manufacture then measure the variation in production characteristics at the site in terms of our current knowledge of Clovis biface technology. I conclude that Topper flintknappers used reduction strategies typical of Clovis-but created a biface assemblage with greater flexibility in design than documented at most other Clovis sites. Clovis groups adapted to local resource conditions and adjusted the organization of their technology accordingly. My fourth chapter analyzes southeastern Clovis point data and biface assemblages from Carson-Conn-Short (TN), Topper, and Williamson (VA) to test the technological implications of Kelly and Todd���s (1988) high-technology-forager model and Anderson���s (1990) staging-area model. Significant subregional variation exists in Clovis biface systems, such as differences in point morphology and the tempo of biface reduction. This variation suggests the subregions represent distinct populations who distinctly altered aspects of their technology but maintained fundamental elements of the Clovis tradition.
Ultimately, I demonstrate there was greater variability in Clovis behavior across America. Recognizing regional variation in the archaeological record is key to understanding the complexities of Clovis origins and dispersal
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