21 research outputs found

    Control of Traction Rail Vehicle with Freewheels

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    This paper is focused on the low-floor tramswith free-wheels driven by PMSM motors, especially ontheir traction control system. The first part describesmodern low-floor trams, particularly the type 15T producedby Škoda Transportation. The second part of the paperpresents the simulations of characteristics operating suchtram in the rail and the results of these simulations. Thelast part of the paper describes the mechanical constructionand electrical equipment of a light experimental rail car,that will be used as an experimental base for a improvementof the control system for the tram 15T

    Effects of advanced laser processing on the microstructure and residual stresses of H13 tool steel

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    Effects of advanced laser processing on the microstructure and residual stresses of H13 tool steel

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    The aim of this paper is to describe the effects of laser processing on the microstructure and residual stresses of laser cladded H13 tool steel on the classical construct steel S355 substrate. This research paper concludes that in this case of laser cladding, phase transformation and not shrinkage is likely to be a dominant effect on the formation of compressive residual stresses along the clad. Furthermore, martensitic structure and unequal concentration of alloying elements was observed on the cross-section of the clad using electron backscattering diffraction and energy-dispersive X-ray spectroscopy

    ChildTalks+: a study protocol of a pre-post controlled, paired design study on the use of preventive intervention for children of parents with a mental illness with focus on eating disorders

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    Background: Children of parents with a mental illness are at high risk of developing a mental disorder as a result of transgenerational transmission. Without effective intervention, they could form the next generation of psychiatric patients. ChildTalks+ is a preventive intervention involving four structured psychoeducational sessions designed for parents affected by a mental disorder and their children. Its aim is to reduce the risk of mental disorders in children of parents with mental illness. This study draws on our clinical practice and involves a group of patients with eating disorders. The aim of the project, which will run in the Czech Republic, is to evaluate the effectiveness of ChildTalks+ methodology. Methods: ChildTalks+ therapists (professionals from health, social, and educational facilities) will recruit 66 families where a parent is treated for a mental disorder and the family includes children aged 6–18. Paired allocation into an intervention group (N = 33) and a control group (N = 33) will be based on the number of risk factors identified in the family. Both groups will complete questionnaires at the baseline, post-test, and follow-up assessments after six and 12 months. The intervention group will receive the ChildTalks+ intervention within 2 months of the baseline assessment; the control group after the last assessment. Questionnaires will be completed by parents and children aged 12+ and, in two cases, 15+ years. Quantitative data will be supplemented with qualitative data from ChildTalks+ therapists working with patients with eating disorders. Discussion: The ChildTalks+ intervention is expected to strengthen parenting competencies and family protective factors, improve family communication, increase awareness of parental mental health issues, and improve the wellbe- ing of children of parents with mental illness with long-term sustainable outcomes. The study should contribute to the evidence base for the ChildTalks+ program and help identify key themes in the implementation of similar preven- tive intervention

    Microstructure and Mechanical Properties of Laser Additive Manufactured H13 Tool Steel

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    Hot working tool steel (AISI H13) is one of the most common die materials used in casting industries. A die suffers from damage due to friction and wear during its lifetime. Therefore, various methods have been developed for its repair to save costs to manufacture a new one. A great benefit of laser additive manufacturing (cladding) is the 3D high production rate with minimal influence of thermal stresses in comparison with conventional arc methods. Residual stresses are important factors that influence the performance of the product, especially fatigue life. Therefore, the aim of this contribution is to correlate the wide range of results for multilayer cladding of H13 tool steel. X‐ray and neutron diffraction experiments were performed to fully describe the residual stresses generated during cladding. Additionally, in‐situ tensile testing experiments inside a scanning electron microscope were performed to observe microstructural changes during deformation. The results were compared with local hardness and wear measurements. Because laser cladding does not achieve adequate accuracy, the effect of necessary post‐grinding was investigated. According to the findings, the overlapping of beads and their mutual tempering significantly affect the mechanical properties. Further, the outer surface layer, which showed tensile surface residual stresses and cracks, was removed by grinding and surface compressive residual stresses were described on the ground surface

    Hepatic Gene Expression Profiles Differentiate Steatotic and Non-steatotic Grafts in Liver Transplant Recipients

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    Background: Liver transplantation leads to non-alcoholic fatty liver disease or non-alcoholic steatohepatitis in up to 40% of graft recipients. The aim of our study was to assess transcriptomic profiles of liver grafts and to contrast the hepatic gene expression between the patients after transplantation with vs. without graft steatosis.Methods: Total RNA was isolated from liver graft biopsies of 91 recipients. Clinical characteristics were compared between steatotic (n = 48) and control (n = 43) samples. Their transcriptomic profiles were assessed using Affymetrix HuGene 2.1 ST Array Strips processed in Affymetrix GeneAtlas. Data were analyzed using Partek Genomics Suite 6.6 and Ingenuity Pathway Analysis.Results: The individuals with hepatic steatosis showed higher indices of obesity including weight, waist circumference or BMI but the two groups were comparable in measures of insulin sensitivity and cholesterol concentrations. We have identified 747 transcripts (326 upregulated and 421 downregulated in steatotic samples compared to controls) significantly differentially expressed between grafts with vs. those without steatosis. Among the most downregulated genes in steatotic samples were P4HA1, IGF1, or fetuin B while the most upregulated were PLIN1 and ME1. Most influential upstream regulators included HNF1A, RXRA, and FXR. The metabolic pathways dysregulated in steatotic liver grafts comprised blood coagulation, bile acid synthesis and transport, cell redox homeostasis, lipid and cholesterol metabolism, epithelial adherence junction signaling, amino acid metabolism, AMPK and glucagon signaling, transmethylation reactions, and inflammation-related pathways. The derived mechanistic network underlying major transcriptome differences between steatotic samples and controls featured PPARA and SERPINE1 as main nodes.Conclusions: While there is a certain overlap between the results of the current study and published transcriptomic profiles of non-transplanted livers with steatosis, we have identified discrete characteristics of the non-alcoholic fatty liver disease in liver grafts potentially utilizable for the establishment of predictive signature
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