1,720,981 research outputs found
Automated implementation of the Peak Stress Method for the fatigue assessment of complex welded structures
Full text linkDealing with the fatigue design of complex welded structures, the Peak Stress Method (PSM) is a rapid approach to the fatigue strength assessment, which is based on the singular, linear-elastic opening, in-plane and out-of-plane shear peak stresses calculated at the weld toe or weld root adopting coarse FE meshes. By adopting the averaged Strain Energy Density (SED) as a fatigue strength criterion, a design stress, the so-called equivalent peak stress, has been defined as a proper combination of the local peak stresses and adopted in conjunction with a reference design fatigue curve to estimate the fatigue lifetime of welded structures. To furtherly enhance the applicability to complex welded structures, the PSM has recently been calibrated by using 10-node tetra elements, which allow to easily discretize complex geometries. Moreover, an interactive analysis tool has been developed within Ansys® Mechanical, in order to automate the application of the PSM to complex both aluminium and steel 3D welded structures subjected to multiaxial fatigue loads. The automated PSM tool has been developed taking advantage of the integrability between Ansys® Mechanical and modern programming languages, enforcing PSM compatibility requirements and automating the implementation tasks and phases of the method. In this perspective, the present work deals with the employment of the PSM tool for the fatigue strength assessment of some complex welded details adopted in modern roller-coaster structures. Due to the geometrical complexity of large-scale structures, private companies usually employ finite element beam models in order to evaluate nominal stresses, that must be compared with appropriate fatigue strength references (FAT classes) in design standards. The assessment procedure proposed in this work aims instead at defining appropriate stress-based FAT classes from the results of automated PSM analyses on the considered joint geometries. Moreover, the proposed approach allows to compensate the limited number of FAT classes and details available in International Standards and Recommendations, when dealing with complex joint geometries
An eight-year report on the implementation of HACCP in a University canteen: Impact on the microbiological quality of meals
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Quality evaluation and discrimination of semi-hard and hard cheeses from the Marche region (Central Italy) using chemometric tools
No full textTwenty-nine semi-hard and hard cheeses from the Marche region (Central Italy) made from either raw or pasteurised ewes', goats', and cows' or a blend of ewes' and cows' milk were analysed for pH, water activity, gross composition, bacterial ecology, and volatile compound profile. Two chemometric tools were used to analyse the available data: principal component analysis (PCA) for preliminary exploratory data analysis, and partial least square discriminant analysis (PLS-DA) for cheese classification by type of milk, treatment (raw versus pasteurised), and origin. PCA and PLS-DA of the outcomes allowed the cheeses to be grouped according to type of milk (cows' versus ewes' or goats') and treatment (raw versus pasteurised), whereas no clear separation between Protected Designation of Origin, niche, and speciality cheeses from similar productions or industrial competitors was attainable. Among the variables, the free fatty acid profile showed a high potential for the discrimination of goats' milk cheeses
The peak stress method to summarise the fatigue behaviour of fillet-welded steel joints subjected to axial or bending loading
No full textThe Peak Stress Method is an engineering, FE-oriented application of the local approach based on the Notch-Stress Intensity Factors (N-SIFs), which quantify the intensity of the local, linear elastic stress field at the potential crack initiation points (either the weld toe or the weld root). All effects due to plate thickness, joint shape and loading mode (axial or bending) are fully included in the N-SIFs, such that a single design curve is sufficient to assess the fatigue strength of arc-welded, fillet-welded joints in structural steels, tested in the as-welded conditions. The design stresses to analysed the fatigue strength are the peak stresses evaluated by FEM at the weld toe or the weld root, which are modelled as sharp notches with a tip radius equal to zero. The mean value of the FE size adopted to calculate the singular peak stresses can be chosen within a range of applicability, while the FE pattern of elements to use is the free mesh generated automatically by Ansys numerical code. Due to the rather coarse meshes required to apply the PSM and its suitability to be used directly with results of three-dimensional FE analyses, it seems that the method is rather useful in the everyday design practise
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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