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wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: CERTIFIED REFERENCE MATERIAL
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A new finite element with variable Young's modulus
PublikacjaThe Finite Element Method (FEM) is a numerical technique that is well-established in the field of engineering. However, in biological sciences, it is justtaking its first steps. Bone tissue is an example of biological material which isexposed to high loads in its natural environment. Practically every movementof the body results in changing stress levels in the bone. Nature copes with thisvery well but when human intervention is...
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Mechanical properties of Precontraint 1202S coated fabric under biaxial tensile test with different load ratios
PublikacjaThe paper describes a method of laboratory tests necessary for identifying the mechanical properties of polyester coated fabrics named Precontraint 1202S with PVDF surface treatment. Two sets of initial material parameters for dense net model and orthotropic model are specified. Material parameters for Precontraint 1202S coated fabric are specified on the basis of the biaxial tensile tests for different load ratios. In order to...
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Utilization of ionic liquids for the enrichment of biogas
PublikacjaThis article discusses the dependence of biogas composition on organic feed material. High amounts of CO2 decrease the calorific value of biogas. Several technologies are reviewed which can be used to increase the calorific value. Special emphasis is laid on ionic liquids as a new absorbing material. ILs have a number of advantages due to their unique properties such as: low melting point, high thermal conductivity, no flammability,...
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Elastoplastic law of Cosserat type in shell theory with drilling rotation
PublikacjaWithin the framework of six-parameter non-linear shell theory, with strain measures of the Cosserat type, we develop small-strain J2-type elastoplastic constitutive relations. The relations are obtained from the Cosserat plane stress relations assumed in each shell layer, by through-the-thickness integration employing the first-order shear theory. The formulation allows for unlimited translations and rotations. The constitutive...
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Torsional buckling and post-buckling of columns made of aluminium alloy
PublikacjaThe paper concerns torsional buckling and the initial post-buckling of axially compressed thin-walled aluminium alloy columns with bisymmetrical cross-section. It is assumed that the column material behaviour is described by the Ramberg–Osgood constitutive equation in non-linear elastic range. The stationary total energy principle is used to derive the governing non-linear differential equation. An approximate solution of the equation...
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The Impact Of The Selected Parameters Of Fdm Manufacturing Technology On Tribological Performance Of Abs–Steel Pair Under Dry Friction
PublikacjaThe paper presents the result of tribological test of ABS and steel samples sliding under dry friction. Polymeric samples were manufactured of ABS material using FDM technology. Testing was carried out in unidirectional sliding in a ring-on-flat contact in a PT-3 tribometer. The scope of tested parameters included volumetric and mass wear, the friction coefficient, and polymeric specimen temperature. Polymeric specimens used in...
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Defining the thermal conductivity of thermally heterogeneous hollow wall bricks used as elements for increasing the comfort of buildings
PublikacjaThe article presents numerical calculation analysis in the scope of determining thermal conductivity coefficientλeq[W/(m·K)] of thermally heterogeneous hollow bricks of thermally heterogeneous structure (a combinationof structural material with thermal insulation material). Numerical calculations were conducted by means ofprofessional software TRISCO-KOBRU 86, serving thermal circulation analysis in a 2D field in stationary approach.The...
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A pin-on-disc study of airborne wear particle emissions from studded tyre on concrete road contacts
PublikacjaStudded tyres wear surfaces of winter roads, generating inhalable airborne particles. In this study, four concrete road materials and two stud geometries were investigated in terms of wear, road material hardness and airborne particle concentration. The sliding contact between studded tyres and road materials was studied using a pin-on-disc machine in a clean chamber. The results show that the normal load and the stud size have...
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Probabilistic estimation of diverse soil condition impact on vertical axis tank deformation
PublikacjaThe calculations of fuel tanks should take into account the geometric imperfections of the structure as well as the variability of the material parameters of the foundation. The deformation of the tank shell can have a significant impact on the limit state of the structure and its operating conditions. The paper presents a probabilistic analysis of a vertical-axis, floating-roof cylindrical shell of a tank with a capacity of 50000...
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Prediction of pile shaft capacity in tension based on some direct CPT methods – Vistula Marshland test site
PublikacjaThis paper presents different CPT methodologies for the prediction of the pile shaft resistance in tension on the example of three reference screw piles of the Jazowa test site in Poland. The shaft capacity was estimated based on the cone resistance, sleeve friction and CPT excess pore water pressure. Three piles with a diameter of 0.4 m and the length...
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Hierarchical dissolved oxygen control for activated sludge processes
PublikacjaA hierarchical controller for tracking the dissolved oxygen reference trajectory in activated sludge processes is proposed and investigated. The removal of nitrogen and phosphorous from wastewater is considered. Typically, an aeration system itself is a complicated hybrid nonlinear dynamical system with faster dynamics compared to the internal dynamics of the dissolved oxygen in a biological reactor. It is a common approach to...
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Temperature influence on tyre/road noise of selected tyres
PublikacjaAir and road temperatures substantially affect road vehicle noise emission. The temperature influence on tyre/road noise depends mainly on tyre-road combination. It is different for dense and porous pavements, for bituminous and cement ones. It differs also depending on tyres. The correction procedures for temperature effect are still under consideration and preparation. Tyre/road noise measurements using CPX method were performed...
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Low-cost data-driven modelling of microwave components using domain confinement and PCA-based dimensionality reduction
PublikacjaFast data-driven surrogate models can be employed as replacements of computationally demanding full-wave electromagnetic simulations to facilitate the microwave design procedures. Unfortunately, practical application of surrogate modelling is often hindered by the curse of dimensionality and/or considerable nonlinearity of the component characteristics. This paper proposes a simple yet reliable approach to cost-efficient modelling...
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Detection of the First Component of the Received LTE Signal in the OTDoA Method
PublikacjaIn a modern world there is a growing demand for localization services of various kinds. Position estimation can be realized via cellular networks, especially in the currently widely deployed LTE (Long Term Evolution) networks. However, it is not an easy task in harsh propagation conditions which often occur in dense urban environments. Recently, time-methods of terminal localization within the network have been the focus of attention,...
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Analysis of GNSS, Hydroacoustic and Optoelectronic Data Integration Methods Used in Hydrography
PublikacjaThe integration of geospatial data in hydrography, performed using different measurement systems, involves combining several study results to provide a comprehensive analysis. Each of the hydroacoustic and optoelectronic systems is characterised by a different spatial reference system and the method for technical implementation of the measurement. Therefore, the integration of hydrographic data requires that problems in selected...
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Retinit im mittleren Geiseltal und in Nordwestsachsen
PublikacjaEs werden historische fossile Harzfunde, bekannt unter dem Namen Retinit, aus ehemaligen Braunkohlenvorkommen in Nordwestsachsen und dem Geiseltal beschrieben. Die Harzproben aus dem Geiseltal wurden mittels Infrarotspektrometer untersucht. Der Vergleich der Spektren mit Referenzspektren zeigt, dass es sich bei den „historischen“ Harzproben um ein Harz vom Retinit- Typ, den oxidierten Krantzit (Oxikrantzit), handelt.
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Niepewność wyniku analizy - sposób obliczania
PublikacjaW pracy przedstawiono sposób obliczania niepewności wyniku analizy zalecany przez EURACHEM. Zamieszczono także podstawowe terminy i definicje, które są stosowane przy konsultowaniu budżetu niepewności i obliczaniu niepewności całkowitej. Praca powstała na podstawie doświadczeń autora w trakcie 2 letniego stażu podoktorskiego, odbytego w Institute for Reference Materials and Measurements w Geel (Belgia), jednym z laboratoriów Komisji...
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Experimental comparison of the transition speed of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
PublikacjaA journal bearing test bench is used to find the transition speed between the hydrodynamic and mixed lubrication regimes for a modified magnetorheological (MR) fluid. It is shown that the transition speed of the bearing can be reduced by applying a local magnetic field near minimum film when it is lubricated with the MR fluid, and that this will only marginally increase friction. The lubricating performance of the MR fluid is compared...
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Separation of Volatile Oxygen-containing Organic Compounds by Gas Chromatography - selectivity comparison of different polarity stationary phases
PublikacjaThis paper present a results of the separation of 36 reference compounds belonging to the group of Volatile Oxygen-Containing Organic Compounds (OVOCs) using capillary gas chromatography with flame ionization detector (GC-FID) and three stationary phases of different polarity. A selectivity has been studied regarding to OVOCs and n -alkanes. The most useful for the separation of the group OVOCs is a polar ionic liquid stationary...
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MEASUREMENT O F HEALTHCARE SYSTEM EFFICIENCY IN OECD COUNTRIES
PublikacjaIncreased spending on healthcare systems in many countries tends to attract attention to their efficiency. The aim of this paper is to evaluate the efficiency of healthcare systems in the OECD countries and indicate causes of inefficiency by applying Data Envelopment Analysis (DEA) and using additive and super-efficiency models. The homogeneity of the sample is assessed and outliers are excluded. A ranking is established on the...