48 research outputs found

    Temperature measurement during abrasive water jet machining (AWJM)

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    This study was undertaken to look for confirmation that heat transfer induced by abrasive water jet machining (AWJM) affects the microstructure of the material cut. The structure of S235JR carbon steel used in the experiments was reported to change locally in the jet impact zone due to the high concentration of energy generated during cutting with the abrasive water jet. It is assumed that some of the energy is transferred into the material in the form of heat. This is particularly true for materials of considerable thickness with a high thermal conductivity coefficient when cutting is performed at low speeds or with high abrasive consumption. The literature on the subject suggests that in AWJM there is little or no thermal energy effect on the microstructure of the material cut. The research described here involved the measurement of the cutting temperature with thermocouples placed at four different distances from the edge. The distances were measured using computed tomography inspection. The thermocouples used in the tests were capable of detecting temperatures of up to 100 degrees C. Locally, temperatures at the edge may reach much higher values. The results of the X-ray diffraction qualitative phase analysis reveal that locally the temperatures may be much higher than the eutectoid temperature. Phase changes occurred along the edge since austenite was observed. This suggests that the temperature in the jet impact zone was much higher than the eutectoid temperature. Optical microscopy was also employed to study the material microstructure. Finally, the material nanohardness was determined.Web of Science1520art. no. 708

    Abrasive waterjet (AWJ) forces-indicator of cutting system malfunction

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    Measurements enabling the online monitoring of the abrasive waterjet (AWJ) cutting process are still under development. This paper presents an experimental method which can be applicable for the evaluation of the AWJ cutting quality through the measurement of forces during the cutting process. The force measuring device developed and patented by our team has been used for measurement on several metal materials. The results show the dependence of the cutting to deformation force ratio on the relative traverse speed. Thus, the force data may help with a better understanding the interaction between the abrasive jet and the material, simultaneously impacting the improvement of both the theoretical and empirical models. The advanced models could substantially improve the selection of suitable parameters for AWJ cutting, milling or turning with the desired quality of product at the end of the process. Nevertheless, it is also presented that force measurements may detect some undesired effects, e.g., not fully penetrated material and/or some product distortions. In the case of a proper designing of the measuring device, the force measurement can be applied in the online monitoring of the cutting process and its continuous control.Web of Science147art. no. 168

    Project Status of the Polish Synchrotron Radiation Facility Solaris

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    Abstract in Undetermined The Polish synchrotron radiation facility Solaris is being built at the Jagiellonian University in Krakow. The project is based on an identical copy of the 1.5 GeV storage ring being concurrently built for the MAX IV project in Lund, Sweden. A general description of the facility is given together with a status of activities. Unique features associated with Solaris are outlined, such as infrastructure, the injector and operational characteristics

    Clostridium difficile infection in Polish pediatric outpatients with inflammatory bowel disease

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    The prevalence of Clostridium difficile infection (CDI) in pediatric patients with inflammatory bowel disease (IBD) is still not sufficiently recognized. We assessed the prevalence of CDI and recurrences in outpatients with IBD. In addition, the influence of IBD therapy on CDI and antimicrobial susceptibility of the potentially causative C. difficile strains was assessed. This was a prospective, single-center, observational study. All specimens were obtained between January 2005 and January 2007 from the IBD outpatient service and screened for C. difficile and its toxins. C. difficile isolates were genotyped by PCR ribotyping. Diagnosis of Crohn’s disease (CD) and ulcerative colitis (UC) was based on Porto criteria. Severity of disease was assessed using the Hyams scale (for Crohn’s disease) and the Truelove–Witts scale (for ulcerative colitis). One hundred and forty-three fecal samples from 58 pediatric IBD patients (21 with Crohn’s disease and 37 with ulcerative colitis) were screened. The risk of C. difficile infection was 60% and was independent of disease type (CD or UC) (χ2 = 2.5821, df = 3, p = 0.4606). About 17% of pediatric IBD patients experienced a recurrence of CDI. All C. difficile strains were susceptible to metronidazole, vancomycin and rifampin. A high prevalence of C. difficile infection and recurrences in pediatric outpatients with IBD was observed, independent of disease type. There was no significant correlation between C. difficile infection and IBD therapy. PCR ribotyping revealed C. difficile re-infection and relapses during episodes of IBD in pediatric outpatients

    Europe-wide expansion and eradication of multidrug-resistant Neisseria gonorrhoeae lineages: a genomic surveillance study

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    Centre for Genomic Pathogen Surveillance and the Euro-GASP study group: Sonja Pleininger, Alexander Indra, Irith De Baetselier, Wim Vanden Berghe, Blaženka Hunjak, Tatjana Nemeth Blažić, Panayiota Maikanti-Charalambous, Despo Pieridou, Hana Zákoucká, Helena Žemličková, Steen Hoffmann, Susan Cowan, Lasse Jessen Schwartz, Rita Peetso, Jevgenia Epstein, Jelena Viktorova, Ndeindo Ndeikoundam, Beatrice Bercot, Cécile Bébéar, Florence Lot, Susanne Buder, Klaus Jansen, Vivi Miriagou, Georgios Rigakos, Vasilios Raftopoulos, Eszter Balla, Mária Dudás, Lena Rós Ásmundsdóttir, Guðrún Sigmundsdóttir, Guðrún Svanborg Hauksdóttir, Thorolfur Gudnason, Aoife Colgan, Brendan Crowley, Sinéad Saab, Paola Stefanelli, Anna Carannante, Patrizia Parodi, Gatis Pakarna, Raina Nikiforova, Antra Bormane, Elina Dimina, Monique Perrin, Tamir Abdelrahman, Joël Mossong, Jean-Claude Schmit, Friedrich Mühlschlegel, Christopher Barbara, Francesca Mifsud, Alje Van Dam, Birgit Van Benthem, Maartje Visser, Ineke Linde, Hilde Kløvstad, Dominique Caugant, Beata Młynarczyk-Bonikowska, Jacinta Azevedo, Maria-José Borrego, Marina Lurdes Ramos Nascimento, Peter Pavlik, Irena Klavs, Andreja Murnik, Samo Jeverica, Tanja Kustec, Julio Vázquez Moreno, Asuncion Diaz, Raquel Abad, Inga Velicko, Magnus Unemo, Helen Fifer, Jill Shepherd, Lynsey PattersonBackground: Genomic surveillance using quality-assured whole-genome sequencing (WGS) together with epidemiological and antimicrobial resistance (AMR) data is essential to characterise the circulating Neisseria gonorrhoeae lineages and their association to patient groups (defined by demographic and epidemiological factors). In 2013, the European gonococcal population was characterised genomically for the first time. We describe the European gonococcal population in 2018 and identify emerging or vanishing lineages associated with AMR and epidemiological characteristics of patients, to elucidate recent changes in AMR and gonorrhoea epidemiology in Europe. Methods: We did WGS on 2375 gonococcal isolates from 2018 (mainly Sept 1-Nov 30) in 26 EU and EEA countries. Molecular typing and AMR determinants were extracted from quality-checked genomic data. Association analyses identified links between genomic lineages, AMR, and epidemiological data. Findings: Azithromycin-resistant N gonorrhoeae (8·0% [191/2375] in 2018) is rising in Europe due to the introduction or emergence and subsequent expansion of a novel N gonorrhoeae multi-antigen sequence typing (NG-MAST) genogroup, G12302 (132 [5·6%] of 2375; N gonorrhoeae sequence typing for antimicrobial resistance [NG-STAR] clonal complex [CC]168/63), carrying a mosaic mtrR promoter and mtrD sequence and found in 24 countries in 2018. CC63 was associated with pharyngeal infections in men who have sex with men. Susceptibility to ceftriaxone and cefixime is increasing, as the resistance-associated lineage, NG-MAST G1407 (51 [2·1%] of 2375), is progressively vanishing since 2009-10. Interpretation: Enhanced gonococcal AMR surveillance is imperative worldwide. WGS, linked to epidemiological and AMR data, is essential to elucidate the dynamics in gonorrhoea epidemiology and gonococcal populations as well as to predict AMR. When feasible, WGS should supplement the national and international AMR surveillance programmes to elucidate AMR changes over time. In the EU and EEA, increasing low-level azithromycin resistance could threaten the recommended ceftriaxone-azithromycin dual therapy, and an evidence-based clinical azithromycin resistance breakpoint is needed. Nevertheless, increasing ceftriaxone susceptibility, declining cefixime resistance, and absence of known resistance mutations for new treatments (zoliflodacin, gepotidacin) are promising.This study was supported by the European Centre for Disease Prevention and Control, the Centre for Genomic Pathogen Surveillance, the Li Ka Shing Foundation (Big Data Institute, University of Oxford), the Wellcome Genome Campus, the Foundation for Medical Research at Örebro University Hospital, and grants from Wellcome (098051 and 099202). LSB was funded by Conselleria de Sanitat Universal i Salut Pública, Generalitat Valenciana (Plan GenT CDEI-06/20-B), Valencia, Spain, and Ministry of Science, Innovation and Universities (PID2020–120113RA-I00), Spain, at the time of analysing and writing this manuscript.info:eu-repo/semantics/publishedVersio

    The requirements and recommendations for the microclimate parameters, the thermal comfort and the thermal load of disabled employees

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    Poczucie komfortu cieplnego pracowników na stanowisku pracy przekłada się bezpośrednio na ich samopoczucie, a zatem również na zwiększenie poziomu koncentracji podczas wykonywania czynności pracy a w konsekwencji – na zwiększenie zarówno poziomu bezpieczeństwa jak i efektywności pracy. Nierzadko osoby niepełnosprawne odczuwają komfort cieplny w warunkach nieco innych niż osoby pełnosprawne. W artykule zamieszczono ogólne informacje dotyczące wymagań i zaleceń w zakresie parametrów mikroklimatu oraz odczuć komfortu i oceny obciążenia cieplnego w stosunku do osób niepełnosprawnych w pracy.Thermal comfort in the workplace translates directly to their well-being, to increase concentration during the work and to increase safety and efficiency. However, should be noted, that people with different disabilities may feel thermal comfort in other range of microclimate parameters than non-disabled people. This article contains general information on the requirements and recommendations for the microclimate parameters thermal comfort and thermal load for workers with disabilities
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