211 research outputs found

    Leak identification in saturated unsteady flow via a Cauchy problem

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    This work is an initial study of a numerical method for identifying multiple leak zones in saturated unsteady flow. Using the conventional saturated groundwater flow equation, the leak identification problem is modelled as a Cauchy problem for the heat equation and the aim is to find the regions on the boundary of the solution domain where the solution vanishes, since leak zones correspond to null pressure values. This problem is ill-posed and to reconstruct the solution in a stable way, we therefore modify and employ an iterative regularizing method proposed in [1] and [2]. In this method, mixed well-posed problems obtained by changing the boundary conditions are solved for the heat operator as well as for its adjoint, to get a sequence of approximations to the original Cauchy problem. The mixed problems are solved using a Finite element method (FEM), and the numerical results indicate that the leak zones can be identified with the proposed method

    Reconstruction of Marine Fisheries Catches for the Republic of Malta (1950-2010)

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     The marine fisheries catches of Malta were reconstructed for the period 1950-2014, including for reported and previously unreported commercial large- and small-scale catches, unmonitored fisheries catches, i.e., subsistence and recreational fisheries, as well as major discards. The present study updates and improves a previous catch reconstruction for Malta for the 1950-2010 time period. Reconstructed marine fisheries catches for Malta are nearly 1.3 times the official landings reported by the FAO and national authorities on behalf of Malta, increasing from around 1,200 t·year-1 in the 1950s to 3,700 t·year-1 in the 2010s. The discrepancy between reported and reconstructed total catches is mostly due to the subsistence catches estimated, which here consist exclusively of on-board consumption and take-home catch of commercial fishers. While the Maltese fisheries statistical system includes procedures to estimate ‘unmonitored’ commercial landings, this contribution documents that it would be beneficial to also account for non-commercial catches

    Machine learning for predicting fracture strain in sheet metal forming

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    Machine learning models are built to predict the strain values for which edge cracking occurs in hole expansion tests. The samples from this test play the role of sheet metal components to be manufactured, in which edge cracking often occurs associated with a uniaxial tension stress state at the critical edges of components. For the construction of the models, a dataset was obtained experimentally for rolled ferritic carbon steel sheets of different qualities and thicknesses. Two types of tests were performed: tensile and hole expansion tests. In the tensile test, the yield stress, the tensile strength, the strain at maximum load and the elongation after fracture were determined in the rolling and transverse directions. In the hole expansion test, the strain for which edge cracking occurs, was determined. It is intended that the models can predict the strain at fracture in this test, based on the knowledge of the tensile test data. The machine learning algorithms used were Multilayer Perceptron, Gaussian Processes, Support Vector Regression and Random Forest. The traditional polynomial regression that fits a 2nd order polynomial function was also used for comparison. It is shown that machine learning-based predictive models outperform the traditional polynomial regression method; in particular, Gaussian Processes and Support Vector Regression were found to be the best machine learning algorithms that enable the most robust predictive models.publishe

    Isomeric states in 253^{253}No

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    6 pagesInternational audienceIsomeric states in 253No have been investigated by conversion-electron and gamma-ray spectroscopy with the GABRIELA detection system. The 31 micro second isomer reported more than 30 years ago is found to decay to the ground state of 253No by the emission of a 167 keV M2 transition. The spin and parity of this low-lying isomeric state are established to be 5/2+. The presence of another longer-lived isomeric state is also discussed

    New high-spin states of 58142^{142}_ {58}Ce and 56140^{140}_{56}Ba from fusion-fission reactions: Proton excitations in the N = 84 isotones

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    High-spin states in the 142^{142}Ce and 140^{140}Ba nuclei have been populated in the 12^{12}C + 238^{238}U and 18^{18}O + 208^{208}Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted Îł\gamma-radiation was detected using the Euroball III and IV arrays. The high-spin yrast and near-to-yrast structures of 142^{142}Ce have been considerably extended. The level scheme of 140^{140}Ba has been extended by six new levels. The newly observed structures in these N = 84 isotones are discussed by analogy with the neighbouring nuclei

    Expression of uncoupling proteins-1,-2 and-3 mRNA is induced by an adenocarcinoma-derived lipid-mobilizing factor

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    The abnormalities of lipid metabolism observed in cancer cachexia may be induced by a lipid-mobilizing factor produced by adenocarcinomas. The specific molecules and metabolic pathways that mediate the actions of lipid-mobilizing factor are not known. The mitochondrial uncoupling proteins-1, -2 and -3 are suggested to play essential roles in energy dissipation and disposal of excess lipid. Here, we studied the effects of lipid-mobilizing factor on the expression of uncoupling proteins-1, -2 and -3 in normal mice. Lipid-mobilizing factor isolated from the urine of cancer patients was injected intravenously into mice over a 52-h period, while vehicle was similarly given to controls. Lipid-mobilizing factor caused significant reductions in body weight (-10%, P=0.03) and fat mass (-20%, P<0.01) accompanied by a marked decrease in plasma leptin (-59%, P<0.01) and heavy lipid deposition in the liver. In brown adipose tissue, uncoupling protein-1 mRNA levels were elevated in lipid-mobilizing factor-treated mice (+96%, P<0.01), as were uncoupling proteins-2 and -3 (+57% and +37%, both P<0.05). Lipid-mobilizing factor increased uncoupling protein-2 mRNA in both skeletal muscle (+146%, P<0.05) and liver (+142%, P=0.03). The protein levels of uncoupling protein-1 in brown adipose tissue and uncoupling protein-2 in liver were also increased with lipid-mobilizing factor administration (+49% and +67%, both P=0.02). Upregulation by lipid-mobilizing factor of uncoupling proteins-1, -2 and -3 in brown adipose tissue, and of uncoupling protein-2 in skeletal muscle and liver, suggests that these uncoupling proteins may serve to utilize excess lipid mobilized during fat catabolism in cancer cachexia
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