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EN
The essential source of errors in machining on five-axis milling centres are errors caused by the improper calibration of a machine tool, setup errors and a process plan which is not designed optimally. For the multilateral machining of the complex, precise parts of machines, a process plan should include, before and during the process, coordinate measurements by means of a touch probe in order to verify previously made surfaces or to determine accurately the position and orientation of a local coordinate system. The uncertainty of these measurements is connected with the estimate precision of performing the manufactured parts. This paper presents a tool devised for determining the uncertainty of the results of coordinate measurements by a simulation method, which is also useful at the stage of machine tool calibration. A basis of this method is a bipartite graph with a tree structure. Transitions in the graph constitute a set of elementary measurement activities and analytical activities which determine the uncertainty of the position and orientation of respective geometric features and abstract objects. Based on the results of the conducted simulation tests it is possible to build analytical models for the rapid determination of measurement uncertainty. The tool devised is aimed at vector dimensioning and therefore it enables simple extension, including integration with geometric dimensioning and tolerancing. This paper includes an example of applying the method devised, which confirms its practicability.
PL
W niniejszej pracy przedstawiono koncepcję rozszerzonej analizy statystycznej wyników pomiarów (dyskretnych sygnałów pomiarowych o charakterze losowym). Sposób jej przeprowadzania zilustrowano przykładem, w którym użyto wyników pomiarów natężenia promieniowania słonecznego. Uzyskane rezultaty pozwoliły na sformułowanie własności proponowanej metody analizy statystycznej oraz wniosków dotyczących określania wpływu pary wodnej na natężenie promieniowania słonecznego, w kontekście pozyskiwania energii elektrycznej przy użyciu ogniw fotowoltaicznych.
EN
This paper presents the concept of extended statistical analysis of measurement results (discrete random measurement signals). The method of its execution is illustrated by an example in which the results of solar radiation intensity measurements were used. The obtained results allowed to formulate the properties of the proposed method of statistical analysis and drawing conclusions regarding the influence of water vapor on the intensity of solar radiation in the context of obtaining electricity with the use of photovoltaic cells.
EN
The sequential multilateration principle is often adopted in geometric error measurement of CNC machine tools. To identify the geometric errors, a single laser tracker is placed at different positions to measure the length between the target point and the laser tracker. However, the measurement of each laser tracker position is not simultaneous and measurement accuracy is mainly subject to positioning repeatability of the machine tool. This paper attempts to evaluate the measurement uncertainty of geometric errors caused by the positioning repeatability of the machine tool and the laser tracker spatial length measurement error based on the Monte Carlo method. Firstly, a direct identification method for geometric errors of CNC machine tools based on geometric error evaluation constraints is introduced, combined with the geometric error model of a three-axis machine tool. Moreover, uncertainty contributors caused by the repeatability of positioning of numerically controlled axes of the machine tool and the laser length measurement error are analyzed. The measurement uncertainty of the geometric error and the volumetric positioning error is evaluated with the Monte Carlo method. Finally, geometric error measurement and verification experiments are conducted. The results show that the maximum volumetric positioning error of the machine tool is 84.1 μm and the expanded uncertainty is 5.8 μm (𝑘 = 2). The correctness of the geometric error measurement and uncertainty evaluation method proposed in this paper is verified compared with the direct geometric error measurement methods.
4
Content available remote Principles of good metrological practice of form deviation measurements
EN
The article concerns the measurements of form using the radial method. The most important factors influencing the obtaining of reliable measurement results of the outlines of the form of rotary elements with the use of measuring instruments operating on the principle of the method of measuring changes in the radius were presented. The principles of good metrological practice ensuring obtaining reliable measurement results at the stage of preparing the instrument, carrying out measurements and performing the analysis of the obtained results in order to determine the parameters are discussed.
PL
Artykuł dotyczy pomiarów zarysów kształtu metodą promieniową. Przedstawiono najważniejsze czynniki wpływające na wiarygodność wyników pomiarów zarysów kształtu elementów obrotowych przeprowadzonych z użyciem przyrządów wykorzystujących metodę pomiaru zmian promienia. Omówiono zasady dobrej praktyki metrologicznej zapewniającej uzyskiwanie wiarygodnych wyników pomiarów na etapie przygotowywania przyrządu, przeprowadzania pomiarów oraz analizowania wyników w celu wyznaczenia parametrów.
PL
W artykule przedstawiono i przedyskutowano wyniki pomiarów stężenia etanolu w zakresie odpowiadającym typowym stężeniom występującym podczas procesu fermentacji piwnej. Zastosowana aparatura to chromatograf gazowy Varian CP-3800 z kolumną kapilarną i detektorem FID. Wzorcowanie chromatografu przeprowadzono z zastosowaniem metody wzorca wewnętrznego. Wyznaczono i przeanalizowano krzywe wzorcowe w zakresie stężeń etanolu 0-10 % obj., na podstawie przedziałów ufności wyznaczonych dla krzywych wzorcowych wyciągnięto wnioski dotyczące możliwej do uzyskania dokładności pomiaru.
EN
The article presents and discusses the results of measurements of ethanol concentration in the range corresponding to the typical concentrations occurring during beer fermentation processes. The apparatus used is a Varian CP-3800 gas chromatograph with a capillary column and a FID detector. The chromatograph was calibrated using the internal standard method. Standard curves in the range of ethanol concentrations 0-10% vol. were determined and analyzed, on the basis of the confidence intervals determined for the calibration curves, conclusions were drawn about a possible accuracy of the measurement.
PL
W związku z rozpoczętą procedurą akredytacji stanowiska do pomiaru wytrzymałości próbek skał, niezbędnym okazało o się przeprowadzenie obliczeń i bilansu niepewności pomiaru siły obciążającej próbkę oraz pojawiających się w niej w wyniku obciążania naprężeń. Odpowiednie eksperymenty wykonywane są z wykorzystaniem maszyny wytrzymałościowej INSTRON 8800 Rock Testing System znajdującej się na wyposażeniu Pracowni Odkształceń Skal IMG PAN. Obiektami generującymi niepewność są w tym przypadku: dynamometr – mierzący siłę obciążającą próbkę (element wyposażenia maszyny INSTRON), oraz suwmiarka – służąca do pomiaru odpowiednich wymiarów badanej próbki. Wykonano odpowiednie obliczenia oraz sporządzono bilans niepewności dla wyznaczania wytrzymałości próbki na rozciąganie na podstawie wyników testu poprzecznego ściskania. W opracowaniu odniesiono się również do wpływu zmian temperatury w laboratorium na wynik końcowy pomiaru Przedstawiony poniżej materiał jest kontynuacją omówionego w roku 2021 zagadnienia, które dotyczyło oznaczania niepewności oznaczania wytrzymałości na ściskanie.
EN
Due to the initiated procedure of accreditation of the stand for measuring the strength of rock samples, it was necessary to carry out calculations and balance the measurement uncertainty of the force loading the sample and the stresses appearing in it as a result of loading. Appropriate experiments are performed using the INSTRON 8800 Rock Testing System testing machine, which is part of the equipment of the Rock Deformation Laboratory of the Strata Mechanics Institute of the Polish Academy of Sciences. Measurement uncertainty is generated in this case by the following sources: dynamometer – measuring the force loading the sample (part of the INSTRON machine equipment), and caliper – used to measure the appropriate dimensions of the tested sample. Appropriate calculations were performed and an uncertainty balance was prepared for determining the tensile strength of the sample based on the results of the transverse compression test. The study also refers to the impact of temperature changes in the laboratory on the final result of the measurement. The material presented in the article is a continuation of the issue discussed in 2021, which concerned the determination of uncertainty in the determination of compressive strength.
PL
Stosowane w praktyce filtry elektroniczne typu MEMS wymagają eksperymentalnego badania charakterystyk amplitudowych i fazowych. Wymaga to opracowania metody pomiarowej, która nie tylko zapewni pomiar charakterystyk, lecz umożliwi równoczesne oszacowanie niepewności tego pomiaru. Opisany sterowany komputerowo system pomiarowy umożliwia pomiary charakterystyk filtrów z zachowaniem spójności pomiarowej przy uwzględnieniu w pełni zautomatyzowanego procesu szacowania niepewności pomiaru. Testy przeprowadzone w trakcie badania charakterystyki przykładowego filtru magnetostrykcyjnego potwierdziły zarówno poprawność zaproponowanego rozwiązania, jak i jego możliwość zastosowania w praktyce.
EN
MEMS type electronic filters used in practice require experimental testing of amplitude and phase characteristics. This requires the development of a measurement method that will not only measure the characteristics, but also allow for the simultaneous estimation of the measurement uncertainty. The computer-controlled measuring system described in the article enables the measurement of filter characteristics while maintaining measurement traceability, taking into account the fully automated process of estimating the measurement uncertainty. The tests carried out during the study of the characteristics of the exemplary magnetostrictive filter confirmed both the correctness of the proposed solution and its applicability in practice.
EN
Non-measured points (NMPs) are one of vital problems in optical measurement. The number and location of NMPs affect the obtained surface texture parameters. Therefore, systematic studying of the NMP is meaningful in understanding the instrument performance and optimizing measurement strategies. This paper investigates the influence of measurement settings on the non-measured points ratio (NMPR) using structured illumination microscopy. It is found that using a low magnification lens, high exposure time, high dynamic range (HDR) lighting levels, and low vertical scanning interval may help reduce the NMPR. In addition, an improved approach is proposed to analyze the influence of NMP on areal surface texture parameters. The analysis indicates that the influence of NMP on some parameters cannot be ignored, especially for extreme height parameters and feature parameters.
EN
At the National Institute of Metrological Research (INRIM) an evaluation of a commercial dual source high resistance bridge has been performed. Its two main measurement modes (single measurements and multiple measurements) have been investigated. The best settle time of a 10:1 measurement of high resistance ratio has been estimated to be about three times the time constant of the circuit involving the resistors. This constant, in turn, depends on the highest value resistor. By means of mathematical estimators, suitable numbers of the readings of the detector have been established in order to minimize noises. A compatibility test at 100 TΩ has shown that the best precision of the commercial bridge is achieved utilizing the multiple measurements mode with the auto update function. This mode also allows the characterization of a resistor as a function of the settle time. This characterization can be useful for the owner of the resistor who can request the laboratory to perform the calibration of the resistor with the settle time which is necessary for him.
PL
Omówiono prezentację multimedialną dotyczącą niepewności pomiaru, przygotowaną w ramach projektu realizowanego w Europejskiej Sieci Metrologicznej MATHMET. Prezentacja w sposób przystępny przedstawia metody wyznaczania współczynnika rozszerzenia podawanego w świadectwach wzorcowania. Będzie uzupełnieniem materiałów szkoleniowych związanych z niepewnością pomiaru.
EN
A multimedia presentation on the measurement uncertainty, prepared as part of the project implemented in the European Metrological Network MATHMET, was presented. In a simple way, it presents the methods of determining the coverage factor given in calibration certificates. It will complement training materials related to measurement uncertainty.
PL
Jednym z tych obszarów działalności laboratoryjnej, któremu w ostatnim czasie poświęca się najwięcej uwagi, jest aspekt spełnienia przez laboratoria realizujące pobieranie próbek jako "stand-alone activity" wymagań normy ISO/IEC 17025:2017 dotyczących oceny i raportowania niepewności pomiaru.
PL
W pracy dokonano analizy kryterium akceptacji pojedynczych wyników oznaczania wytrzymałości na ściskanie w ocenie identyczności, dla zbioru 10 hipotetycznych wyników. Przedstawiono 3 podejścia, z których 2 wynikają z interpretacji zapisów normy oraz alternatywny, przedstawiony przez autora, jako przykład racjonalnego powodu, uzasadniającego odrzucenie pojedynczego wyniku badania.
EN
The paper analyses the criterion for acceptance of single compressive strength results in the evaluation of identity, for a set of 10 hypothetical results. Three approaches are presented, 2 of which are derived from the interpretation of the standard’s provisions and an alternative one, presented by the author, as an example of an acceptable reason to justify disregarding an individual test value.
13
Content available remote Uncertainties in the measurement of relative doses in radiotherapy
EN
Both the measurement of the dose and the measurement of its distribution, like any other measurements, are subject to measurement uncertainties. These uncertainties affect all dose calculations and dose distributions in a patient’s body during treatment planning in radiotherapy. Measurement uncertainty is not a medical physicist's error, but an inevitable element of their work. Planning the dose distribution in a patient’s body, we often try to reduce it in the volume of critical organs (OaR - Organ at Risk) or increase the minimum dose in the PTV region by a few percent. It is believed that the measurement uncertainty should be taken into account in these calculations at the stage of treatment planning. The paper presents the method of calculating the measurement uncertainty for different physical quantities in radiotherapy as percentage depth dose, profile function and output factor, due to the fact that these quantities have a particular impact on the calculated dose distributions in a patient’s body. The uncertainties that must be taken into account in planning treatment the planned dose per fraction and real in PTV, maybe different up to 4%.
PL
Artykuł przybliża zagadnienie badania gradientu temperatury w termostatach i w komorach klimatycznych oraz jego wpływ na niepewność pomiaru. Na podstawie badań przeprowadzonych w termostacie Julabo F12, wykonanych w Laboratorium Długości i Termometrii OUM w Bydgoszczy, opracowano analizę uzyskania optymalnych warunków pomiaru, pozwalających na utrzymanie wymaganego poziomu CMC w laboratorium.
EN
The article presents the problem of studying temperature gradient in thermostats and climatic chambers and their impact on measurement uncertainty. Based on the tests of gradients in the Julabo F12 thermostat, carried out at the Length and Thermometry Laboratory of the Regional Office of Measures in Bydgoszcz, an analysis of obtaining optimal measurement conditions allowing to maintain the required level of CMC in the laboratory was developed.
PL
W artykule omówiono podstawowe zasady tworzenia modeli pomiaru przedstawione w nowym dokumencie opublikowanym przez Wspólny Komitet ds. Przewodników w Metrologii. Celem jest przybliżenie głównych treści w nim zawartych. Dokument jest ważnym materiałem, który może być wykorzystywany w laboratoriach badawczych, wzorcujących i naukowych.
EN
The article discusses the basic principles for creating the measurement models presented in a new document published by the Joint Committee for Guides in Metrology. The aim of the article is description of the main ideas expressing in this Guide. The document is an important material that can be used in testing, calibration and scientific laboratories.
EN
Calibration of RF power sensors is crucial issue in RF power measurements. Many calibration laboratories use the direct comparison transfer system with a signal generator and a power splitter. Increasing performance of modern vector network analyzers makes it possible to perform a power sensor calibration with acceptable uncertainties. The main advantage when using a VNA is a simple measurement setup with a wide frequency range (up to 50 GHz, limited only by the VNA and the standard power sensor), where all of required components, i.e. signal generator, a directional coupler and a reference power indicator are built in the VNA technology. This paper reports performing a VNA-based RF power sensors calibration for 10 MHz – 18 GHz band, carried out in the Laboratory of Electric, Electronic and Optoelectronic Metrology at the National Institute of Telecommunications in Warsaw, Poland. In order to validate the proposed solution two of power sensors were calibrated at a reference laboratory. The validation consisted of two steps. At first, one of those characterized power sensors was calibrated at our laboratory in direct comparison transfer system. Finally, the results obtained from the VNA-based system were compared with the previously obtained ones.
EN
Fuel consumption measurement itself is a demanding process and it is difficult to determine the exact consumption of a vehicle. Fuel consumption can be determined in various ways. One way to determine consumption is through driving tests. We know several types of driving tests. Nowadays, most vehicles and all new vehicles can provide a wealth of data to the driver directly during vehicle operation. One of them is the data on the consumption of the vehicle also through the on-board computer located in the vehicle. The information provided to the driver may not reflect reality. In most cases, they are inaccurate and do not correspond to reality. Therefore, the subject of the research will be to verify the accuracy of the provided data on vehicle consumption by the on-board computer. The aim of the research will be to determine the extent to which consumption data are true. Vehicle consumption, as well as measurements are performed on one vehicle in every day traffic. This will ensure that it is possible to compare the measured data with each other.
EN
The article presents methodology for testing the electric strength of vacuum chambers designed for modern medium voltage switchgear developed by the authors, using two innovative test stands designed and constructed by the research team above. Verification of the correctness of operation of the test stands, as well as the validity of the developed methodology was carried out by performing a series of tests. It was determined that below certain pressure values in the tested chamber (from about 5:0 x 100 Pa for station 1 and for about 4:0 x 10-1 Pa for station 2), the electric strength maintains a constant value, which guarantees stable operation of the vacuum chamber. The values of the total measurement uncertainty for the electric strength tests were also estimated.
PL
W pracy analizie poddano wyniki badań przyczepności cementowych zapraw klejących do płytek ceramicznych wykonanych na zlecenie organów nadzoru budowlanego w latach 2016-2020. Znaczna ilość zbadanych cementowych zapraw klejących nie spełniła kryterium odbiorczego i zgodnie z regulacjami prawnymi ich producent zobowiązany był do niezwłocznego wycofania wyrobu z rynku. Przy ocenie zgodności wyników z kryteriami stosowana jest reguła prostej akceptacji, co oznacza, że wyrób został uznany za zgodny lub niezgodny w odniesieniu do wyniku, jeśli wynik ten, bez uwzględnienia zmienności wynikającej z niepewności pomiarowej, spełnił bądź nie spełnił wymagań progowych. Omówiono możliwe sytuacje, w których producent dokonał prawidłowej oceny i weryfikacji stałości właściwości użytkowych [AVCP] cementowej zaprawy klejącej, zaś ocena laboratorium była negatywna z powodu nie uwzględnienia zmienności wynikającej z niepewności pomiarowej lub specyfiki wieloetapowej metody badawczej. Analizę wyników badań przeprowadzono według podziału na cementowe zaprawy klejące klasy C1 i C2 oraz według podziału na laboratoria notyfikowane, w których wykonane zostały badania. Analizując proporcje pomiędzy wyrobami spełniającymi i niespełniającymi wymagań w dwóch laboratoriach wykonujących badania na zlecenie organów nadzoru budowlanego, stwierdzono duże różnice pomiędzy nimi.
EN
The paper analyzes the results of adhesion tests of cementitious adhesives to ceramic tiles, commissioned by construction supervision authorities in 2016-2020. A significant number of the tested cementitious adhesives did not meet the acceptance criteria. Following legal regulations, their manufacturer was obliged to withdraw the product from the market immediately. When assessing the compliance of the results with the requirements, the simple acceptance rule is applied. It means that the product is considered compliant only if the result met the threshold requirements. The results variability estimated from the measurement uncertainty is not taken under consideration. Possible situations in which the manufacturer correctly assessed and verified the constancy of performance [AVCP] of the cementitious adhesive, but the laboratory assessment was negative due to not including the variability resulting from measurement uncertainty, or the specificity of the multi-stage research methodology were discussed. The analysis of the test results was carried out according to the division into C1 and C2 class cementitious adhesives, and also according to the division into notified laboratories, where the tests were performed. When analyzing the number of products that meet or not the requirements, significant differences were found between laboratories carrying out tests commissioned by construction supervision authorities.
EN
Several use cases from the areas of manufacturing and process industry, require highly accurate sensor data. As sensors always have some degree of uncertainty, methods are needed to increase their reliability. The common approach is to regularly calibrate the devices to enable traceability according to national standards and Syst\`eme international (SI) units - which follows costly processes. However, sensor networks can also be represented as Cyber Physical Systems (CPS) and a single sensor can have a digital representation (Digital Twin) to use its data further on. To propagate uncertainty in a reliable way in the network, we present a system architecture to communicate measurement uncertainties in sensor networks utilizing the concept of Asset Administration Shells alongside methods from the domain of Organic Computing. The presented approach contains methods for uncertainty propagation as well as concepts from the Machine Learning domain that combine the need for an accurate uncertainty estimation. The mathematical description of the metrological uncertainty of fused or propagated values can be seen as a first step towards the development of a harmonized approach for uncertainty in distributed CPS in the context of Industrie 4.0. In this paper, we present basic use cases, conceptual ideas and an agenda of how to proceed further on.
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