3,018 research outputs found

    Nonlinear analysis of beams, plane frames and arch using a dierent co-rotating beam element

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    En este trabajo se describe la formulación corrotacional de un elemento de viga que utiliza distintas teorías, Euler-Bernoulli, Timoshenko y Euler-Bernoulli incluyendo el acoplamiento entre los efectos de los esfuerzos de flexión y axil lo que genera coeficientes no lineales en la matriz de rigidez elástica de dicho elemento. La cinemática corrotacional se basa en la separación del movimiento de un sólido en una parte deformacional y otra en movimiento de cuerpo rígido. La parte deformacional del movimiento es representada por tres grados de libertad: una traslación debido al esfuerzo axil y por las rotaciones nodales debidas a la flexión del elemento. A nivel local se obtienen los esfuerzos internos mediante el princípio de los trabajos virtuales una vez definidas las funciones de interporlación que describen el movimiento deformacional para cada teoría de viga utilizada. Se describe de forma detallada la obtención de las matrices de rigideces elástica para los tres tipos de elementos de viga. A través de algunos ejemplos numéricos se muestra la habilidad del elemento para obtener el comportamiento no lineal de vigas, pórticos y arcos.The present work uses a co-rotating approach for obtain the internal forces and tangent stiffness matrices for three plane beam elements. All of them are based on the same co-rotational approach, and differ by the strain definition used in the local co-rotational coordinate system. Based on the Bernoulli assumption, the first two elements use a linear and a shallow arch strain definition, respectively. The third element is based on the Timoshenko assumption with linear interpolations for the displacements. Some examples are presented and the numerical results demonstrate that the beam elements here presented are able to perform the nonlinear analysis of plane frames and 2D arches and to handle large rotations too.Peer Reviewe

    The Analysis of the Prevalence of Diabetes in the Third Age in a Northeast State Between the Years From 2002 To 2013

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    Diabetes potentiates when the body can not control the amount of glucose (sugar) in the blood. This disease develops when the body does not produce enough amounts of the hormone called insulin. The elderly are more fragile in not producing adequate insulin for their proper functioning, since the prevalence is related to aging, sedentary lifestyle and obesity, and these last two factors, in turn, intensify with the advancing age. The decompensated glycemia accentuates frequent difficulties in this phase of life. It can incapacitate the elderly because it increases the risk of dementias such as Alzheimer’s, in addition to diabetic neuropathy, which causes the elderly to lose firmness on the floor, the use of many medications and other problems that impact the quality of life and increase the risk of death

    Nonlinear analysis of plane frames using a co-rotating Timoshenko beam element

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    En este trabajo se describe la formulación corrotacional de un elemento de viga unificado que integra las teorías de vigas de Euler-Bernoulli y de Timoshenko y que no presenta bloqueo por deformación a cortante. La cinemática corrotacional se basa en la separación del movimiento de un sólido en una parte deformacional, y la otra, en movimiento de cuerpo rígido. La parte deformacional del movimiento es representada por tres modos de deformaciones naturales que son generados por el esfuerzo axil, la flexíon pura y la flexíon simple, respectivamente. Los esfuerzos generados por los modos naturales de deformación son auto-equilibrados lo que posibilita la obtención de la matriz de rigidez tangente corrotacional consistente. Se describe de forma detallada la obtención de las matrices de rigideces elástica, geométrica y corrotacional. A través de algunos ejemplos numéricos se muestra la habilidad del elemento de tratar con grandes rotaciones de cuerpo rígido.The present work describes a co-rotating shear flexible beam element without shear locking and integrating Euler-Bernoullis and Timoshenkos beam theories. The co-rotational kinematics is based on the separation of the motion in deformational and rigid body components. The deformation of the beam element is composed by three natural modes of deformation: the extension mode, the symmetric bending mode, and the anti-symmetric bending mode. The respective generalized stresses from these natural modes are self-balanced allowing the achievement of a consistent tangent stiffness matrix. In this paper, it is detailed and deduced all the algebraic steps for the deduction of the elastic stiffness matrix, the geometric stiffness matrix, and the co-rotation stiffness matrix. Some examples are presented and the numerical results demonstrate that the beam element here presented is able to handle large rotations.Peer Reviewe

    New approach addressing sustainability in urban areas using sustainable city models

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    A brief analysis of the environmental, social and economic paradigm of nowadays cities, allows reaching a simple conclusion: current cities are not sustainable. Considering this, it is very important to study the causes of cities problems and to develop city models implementing sustainability practices. There are a limited number of studies developing sustainable city models, but the scientific community lacks even more studies about the rehabilitation of current cities to implement these models. This work emerges with the objective of analysing how it is possible to implement sustainability practices in cities through the development of a sustainable city model and an urban rehabilitation plan. The development of sustainable city models is a very complex topic and the analysis of the literature shows that it is necessary to consider the relation between environmental and social aspects in the development of sustainable cities, while taking special concerns when considering the economic issues. It was also concluded that sustainable city models and rehabilitation plans should be subject to sustainability assessments and should consider the active participation of its inhabitants. In fact, a city can only be sustainable if its population is in harmony with the city model and we can only assess results by predicting and measuring performance levels.(undefined

    BIODIVERSITY IN THE CATCHMENT OF HIYARE RESERVOIR

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    Data are presented on the site characteristics and land-use types, and on speciesof trees, shrubs, fishes, tetrapod reptiles, snakes, amphibians and birds. Theendemicity ofthe tree and shrub species is especially high, at -17.5 and 3l.5%.The catchment is therefore importantfor the preservation ofbiodiversity, as wellasfor its contribution to the water supply of the town ofGalle

    A wide array of lignin-related phenolics are oxidized by an evolved bacterial dye-decolourising peroxidase

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    Lignin is the second most abundant natural polymer next to cellulose and by far the largest renewable source of aromatic compounds on the planet. Dye-decolourising peroxidases (DyPs) are biocatalysts with immense potential in lignocellulose biorefineries to valorize emerging lignin building blocks for environmentally friendly chemicals and materials. This work investigates the catalytic potential of the engineered PpDyP variant 6E10 for the oxidation of 24 syringyl, guaiacyl and hydroxybenzene lignin-phenolic derivatives. Variant 6E10 exhibited up to 100-fold higher oxidation rates at pH 8 for all the tested phenolic substrates compared to the wild-type enzyme and other acidic DyPs described in the literature. The main products of reactions were dimeric isomers with molecular weights of (2 × MWsubstrate - 2 H). Their structure depends on the substitution pattern of the aromatic ring of substrates, i.e., of the coupling possibilities of the primarily formed radicals upon enzymatic oxidation. Among the dimers identified were syringaresinol, divanillin and diapocynin, important sources of structural scaffolds exploitable in medicinal chemistry, food additives and polymers.info:eu-repo/semantics/publishedVersio

    Exploring Tourist Flow Patterns through Geotagged Social Media Data: A Case Study from Sri Lanka

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    Tourism studies often rely on conventional methods such as interviews and site-specific surveys to collect data on tourist behaviour, mobility patterns, and preferences. However, these methods can be expensive, time-consuming, and limited in scope. Additionally, accurately tracing tourist travel paths can be challenging due to recall bias. Recently, user generated content on social media platforms have emerged as an alternative data source in tourism studies. In this study, we used geotagged posts on Flickr to understand the dominant paths taken by inbound tourists in Sri Lanka. The methodology consisted of three steps. First, geotagged photographs were collected from the Flickr API spanning a ten-year period, from 2012 to 2022. These photographs included metadata such as user ID, the timestamp of photo capture, and geo coordinates indicating where the photo was taken. Second, a density-based clustering algorithm was utilized to identify tourist hotspots. Finally, the Markov Chain model was employed to calculate transition probabilities among different attractions, revealing dominant travel routes within the country. Study’s findings indicate that Cultural heritage attractions were the most popular, comprising 55% of all attractions identified by the algorithm, and are particularly popular in districts such as Anuradhapura, Polonnaruwa, Matale, Kandy, and Galle. Nature-based attractions, constituting 37% of the total, were mainly located in Nuwara Eliya and Badulla Districts, as well as Yala National Park in Hambantota District. For coastal tourism, Galle and Matara Districts were the top preferences. The analysis confirms dominant travel patterns between North Central, Central, and Southwest coast regions. Notably, Galle, Kandy, Matale, Matara, Nuwara Eliya, and Colombo attract tourists from a more diverse array of regions compared to other districts in the country, showcasing their significance as tourist hubs. The study findings highlight opportunities in Jaffna for cultural-heritage tourism, the Eastern coast for coastal tourism, and the central highlands for tea tourism. It also emphasizes the need to develop the less-visited natural sites to ease pressure on popular National Parks. This research's significance lies in its contribution to informed decision-making and the sustainable management of tourist destinations. By understanding tourist mobility patterns and identifying popular attractions through social media data, policymakers can effectively manipulate visitor flows and mitigate excessive tourist pressure, while preserving the authenticity and allure of these destinations.   Keywords: Sustainable tourism, Geotagged photographs, Social media, Tourist mobility, Flick

    Архієпископ Кримський Лука про способи духовного оздоровлення Кримської єпархії

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    In the past decade, mass-spectrometry-based methods have emerged for the quantitative profiling of dynamic changes in protein phosphorylation, allowing the behavior of thousands of phosphorylation sites to be monitored in a single experiment. However, when one is interested in specific signaling pathways, such shotgun methodologies are not ideal because they lack selectivity and are not cost and time efficient with respect to instrument and data analysis time. Here we evaluate and explore a peptide-centric antibody generated to selectively enrich peptides containing the cAMP-dependent protein kinase (PKA) consensus motif. This targeted phosphoproteomic strategy is used to profile temporal quantitative changes of potential PKA substrates in Jurkat T lymphocytes upon prostaglandin E2 (PGE2) stimulation, which increases intracellular cAMP, activating PKA. Our method combines ultra-high-specificity motif-based immunoaffinity purification with cost-efficient stable isotope dimethyl labeling. We identified 655 phosphopeptides, of which 642 (i.e. 98%) contained the consensus motif [R/K][R/K/X]X[pS/pT]. When our data were compared with a large-scale Jurkat T-lymphocyte phosphoproteomics dataset containing more than 10,500 phosphosites, a minimal overlap of 0.2% was observed. This stresses the need for such targeted analyses when the interest is in a particular kinase. Our data provide a resource of likely substrates of PKA, and potentially some substrates of closely related kinases. Network analysis revealed that about half of the observed substrates have been implicated in cAMP-induced signaling. Still, the other half of the here-identified substrates have been less well characterized, representing a valuable resource for future research

    A guided search non-dominated sorting genetic algorithm for the multi-objective university course timetabling problem

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    Copyright @ Springer-Verlag Berlin Heidelberg 2011.The university course timetabling problem is a typical combinatorial optimization problem. This paper tackles the multi-objective university course timetabling problem (MOUCTP) and proposes a guided search non-dominated sorting genetic algorithm to solve the MOUCTP. The proposed algorithm integrates a guided search technique, which uses a memory to store useful information extracted from previous good solutions to guide the generation of new solutions, and two local search schemes to enhance its performance for the MOUCTP. The experimental results based on a set of test problems show that the proposed algorithm is efficient for solving the MOUCTP
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