270 research outputs found

    Effect of the structural parameters changes in the multi-strand tundish on the non-metallic inclusions distribution and separation

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    The aim of presented studies was to investigate the fluid flow change and non-metallic inclusions removal changes due to tundish construction modifications. In presented study, numerical simulations were used. Numerical simulations are carried out with the finite-volume commercial code ANSYS Fluent. Steady-state casting conditions for the flow structure and the inclusions removal process are analysed

    Analysis of liquid steel flow in a multi-strand tundish using numerical methods

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    The article presents the results of liquid steel flow and mixing in tundish when applying turbulence inhibitor to modernize the tundish working zone. The flow of six-strand continuous casting tundish of a trough-type was investigated with numerical modeling. For turbulence modeling, the Reynolds-Averaged Navier-Stokes (RANS) equation and the Large Eddy Simulation (LES) methods have been used. Numerical simulations are carried out with the finitevolume commercial code AnsysFluent

    Validation of numerical model of a liquid flow in a tundish by laboratory measurements

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    The article presents results of physical and numerical modelling of steel flow through a tundish of continuous casting machine. In numerical calculations the influence of mesh density was tested and the correctness of the flow description in the near-wall region was checked using Standard Wall Function model. Obtained results were verified using experimental results of velocity field (PIV method) coming from a water tundish model

    Numerical and experimental analysis of vortex sheets behind lifting surfaces

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77273/1/AIAA-1992-409-534.pd

    MADS+: discovery of differential splicing events from Affymetrix exon junction array data

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    Motivation: The Affymetrix Human Exon Junction Array is a newly designed high-density exon-sensitive microarray for global analysis of alternative splicing. Contrary to the Affymetrix exon 1.0 array, which only contains four probes per exon and no probes for exon–exon junctions, this new junction array averages eight probes per probeset targeting all exons and exon–exon junctions observed in the human mRNA/EST transcripts, representing a significant increase in the probe density for alternative splicing events. Here, we present MADS+, a computational pipeline to detect differential splicing events from the Affymetrix exon junction array data. For each alternative splicing event, MADS+ evaluates the signals of probes targeting competing transcript isoforms to identify exons or splice sites with different levels of transcript inclusion between two sample groups. MADS+ is used routinely in our analysis of Affymetrix exon junction arrays and has a high accuracy in detecting differential splicing events. For example, in a study of the novel epithelial-specific splicing regulator ESRP1, MADS+ detects hundreds of exons whose inclusion levels are dependent on ESRP1, with a RT-PCR validation rate of 88.5% (153 validated out of 173 tested)

    Flow and mixing of liquid steel in multi-strand tundish delta type – physical modelling

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    The article presents the results of liquid steel flow and mixing in tundish when applying different equipment to modernize the tundish working zone. The six-strand continuous casting tundish of a trough-type was studied. Such tundish is an object with geometry adjusted to the conditions of particular CC machine, which is installed in one of a polish steel plant. The problems suggested in research were solved basing on physical model experiment

    Characterization of sequences and mechanisms through which ISE/ISS-3 regulates FGFR2 splicing

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    Alternative splicing of fibroblast growth factor receptor-2 (FGFR2) mutually exclusive exons IIIb and IIIc results in highly cell-type-specific expression of functionally distinct receptors, FGFR2-IIIb and FGFR2-IIIc. We previously identified an RNA cis-element, ISE/ISS-3, that enhanced exon IIIb splicing and silenced exon IIIc splicing. Here, we have performed comprehensive mutational analysis to define critical sequence motifs within this element that independently either enhance splicing of upstream exons or repress splicing of downstream exons. Such analysis included use of a novel fluorescence-based splicing reporter assay that allowed quantitative determination of relative functional activity of ISE/ISS-3 mutants using flow cytometric analysis of live cells. We determined that specific sequences within this element that mediate splicing enhancement also mediate splicing repression, depending on their position relative to a regulated exon. Thus, factors that bind the element are likely to be coordinately involved in mediating both aspects of splicing regulation. Exon IIIc silencing is dependent upon a suboptimal branchpoint sequence containing a guanine branchpoint nucleotide. Previous studies of exon IIIc splicing in HeLa nuclear extracts demonstrated that this guanine branchsite primarily impaired the second step of splicing suggesting that ISE/ISS-3 may block exon IIIc inclusion at this step. However, results presented here that include use of newly developed in vitro splicing assays of FGFR2 using extracts from a cell line expressing FGFR2-IIIb strongly suggest that cell-type-specific silencing of exon IIIc occurs at or prior to the first step of splicing

    Methodology of inclusions removing from steel flowing through the tundish

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    Obtaining high quality steels mainly depends on the quantity of non-metallic inclusions contained into it and this, in turn, to a large extent on the structure of the flow in the tundish. Optimization of the flow of liquid steel through the tundish makes it possible to control the trajectory of inclusions and thereby to improve the conditions of their outflow into the slag layer. The following article presents an analysis of research opportunities of the inclusions distribution and removing process from the steel flowing through the tundish, resulting in reconstruction of the own research facility

    Flexible n-i-p thin film silicon solar cells on polyimide foils with textured ZnO:Ga back reflector

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    In thin film silicon solar cells on opaque substrates in n-i-p deposition sequence where the textured transparent conductive oxide (TCO) layer serves as a back reflector, one can independently optimize the morphology of the TCO layer without compromise on transparency and conductivity of this layer and further adjust the electro-optical properties of the back contact by using additional layers on top of the textured TCO. In the present work, we use this strategy to obtain textured back reflectors for solar cells in n-i-p deposition sequence on non-transparent flexible plastic foils. Gallium doped ZnO (ZnO:Ga) films were deposited on polyimide substrates by DC magnetron sputtering at a temperature of 200 °C. A wet-chemical etching step was performed by dipping the ZnO:Ga covered foil into a diluted HCl solution. The textured ZnO:Ga is then coated with a highly reflective Ag/ZnO double layer. On this back reflector, we develop thin film silicon solar cells with a microcrystalline silicon absorber layer. The current density for the cell with the textured ZnO:Ga layer is ~ 23 mA/cm2, 4 mA/cm2 higher than the one without such layer, and a maximum efficiency of 7.5% is obtained for a 1 cm2 cell.Fundação para a Ciência e a Tecnologia (FCT

    MATS: a Bayesian framework for flexible detection of differential alternative splicing from RNA-Seq data

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    Ultra-deep RNA sequencing has become a powerful approach for genome-wide analysis of pre-mRNA alternative splicing. We develop MATS (multivariate analysis of transcript splicing), a Bayesian statistical framework for flexible hypothesis testing of differential alternative splicing patterns on RNA-Seq data. MATS uses a multivariate uniform prior to model the between-sample correlation in exon splicing patterns, and a Markov chain Monte Carlo (MCMC) method coupled with a simulation-based adaptive sampling procedure to calculate the P-value and false discovery rate (FDR) of differential alternative splicing. Importantly, the MATS approach is applicable to almost any type of null hypotheses of interest, providing the flexibility to identify differential alternative splicing events that match a given user-defined pattern. We evaluated the performance of MATS using simulated and real RNA-Seq data sets. In the RNA-Seq analysis of alternative splicing events regulated by the epithelial-specific splicing factor ESRP1, we obtained a high RT–PCR validation rate of 86% for differential exon skipping events with a MATS FDR of <10%. Additionally, over the full list of RT–PCR tested exons, the MATS FDR estimates matched well with the experimental validation rate. Our results demonstrate that MATS is an effective and flexible approach for detecting differential alternative splicing from RNA-Seq data
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