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Porównanie klasycznych i odpornych metod estymacji parametrów liniowego równania przetwarzania w procedurze wzorcowania chromatografu gazowego

Ilewicz Witold

Przegląd Elektrotechniczny

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2023

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R. 99, nr 10

204--207

PL

W artykule przedstawiono, porównano i przedyskutowano wyniki wyznaczania parametrów krzywej wzorcowania chromatografu gazowego dla metody wzorca wewnętrznego. Celem wzorcowania było określanie stężęnia etanolu w ciekłych próbkach spożywczych. Ze zbioru 168 wyników eksperymentalnych wyselekcjonowano 12 wyników odstających. Na podstawie danych eksperymentalnych skonstruowano zbiory testowe zawierające wyniki odstające. Parametry krzywej wzorcowej wyznaczano 2 metodami klasycznymi (MNK, WMNK) oraz 3 metodami odpornymi na występowanie błędów grubych: z zastosowaniem winsoryzacji błędów resztowych, z zastosowaniem funkcji czułości Hubera oraz z zastosowaniem metody najmniejszej mediany kwadratu błędów resztowych. Wyniki wzorcowania uzyskane 5 metodami porównano, przedstawiono wnioski.

EN

The article presents, compares and discusses the results of determining the parameters of the gas chromatograph calibration curve for the internal standard method. The purpose of the calibration was to determine the concentration of ethanol in liquid food samples. From a set of 168 experimental results, 12 outliers were selected. From the obtained data, test sets containing the outlier results were constructed. The parameters of the calibration curve were determined by 2 classical methods (LS, WLS) and 3 methods resistant to the occurrence of gross errors: using winsorization of residual errors, using Huber's sensitivity function and using the method of the least median square of residual errors. Calibration results obtained by the 5 methods were compared, conclusions were drawn.

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Effect of the Small Field of View and Imaging Parameters to Image Quality and Dose Calculation in Adaptive Radiotherapy

Ubaidillah Allam, Fauzia Annisa Rahma, Purnomo Adi Teguh, Nasution Nuruddin, Wibowo Wahyu Edy, Pawiro Supriyanto Ardjo

Polish Journal of Medical Physics and Engineering

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2023

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Vol. 29, Iss. 2

130--142

EN

The use of cone beam computed tomography (CBCT) for dose calculation in adaptive radiotherapy has been investigated in many studies. Proper acquisition and reconstruction of preset parameters could improve the accuracy of dose calculation based on CBCT images. This study evaluated the impact of the modified image acquisition and preset reconstruction parameter available in X-Ray Volumetric Imaging (XVI) to improve CBCT image quality and dose calculation accuracy. Calibration curves were generated by scanning the CIRS phantom using CBCT XVI Elekta 5.0.4 and Computed Tomography (CT) Simulator Somatom, which served as CT image reference. Rando and Catphan 503 phantoms were scanned with various acquisition and reconstruction parameters for dose accuracy and image quality tests. The image quality test is uniformity, low contrast visibility, spatial resolution, and geometrical scale test for each image by following the XVI image quality test module. Acquisition and reconstruction parameters have an impact on the Hounsfield Unit (HU) value that is used as the HU-Relative Electron Density (RED) calibration curve. The dose difference for all the calibration curves was within 1% and passed the gamma passing rate. Images acquired using 120 kVp, F1 (with Bowtie Filter), and 50 mA (F1-120-50-10) scored the highest Gamma Index (GI) of 98.5%. For the image quality test, it scored 1.20% on the uniformity test, 2.14% on the low contrast visibility test, and 11 lp/cm on the spatial resolution test. However, F1-120-50-10 reconstructed with different reconstructions scored 3.83% and 4 lp/cm in contrast and spatial resolution test, respectively. CBCT reconstruction parameters work as a scatter correction. It could improve the dose accuracy and image quality. Nevertheless, without adequate CBCT acquisition protocols, it would produce an image with high uncertainty and cannot be fixed with reconstruction protocols. The F1-120-50-10 protocols generate the highest dose accuracy and image quality.

3

Szacowanie niepewności pomiaru stężenia etanolu w procesie fermentacji piwnej metodą chromatografii gazowej z detektorem FID

Ilewicz Witold, Skupin Piotr, Szotek Karolina

Przegląd Elektrotechniczny

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2022

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R. 98, nr 12

27--30

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.

4

Calibration of Gafchromic XR-RV3 film under interventional radiology conditions

Kidoń Joanna, Polaczek-Grelik Kinga, Gołba Krzysztof, Wojakowski Wojciech, Ochała Andrzej

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 2

165--173

EN

Introduction: The purpose of the study was the calibration of Gafchromic films in clinical interventional radiology conditions and the assessment of the influence of dose range, the shape of the fitting curve, and its practical application. The aim of the work was to show how practically perform calibration in a wide range of doses. Material and methods: Gafchromic XR–RV3 films were included in the study. The calibration was performed for A and B film series separately. Doses from the range of 0 – 8 Gy were used. Film dosimeters were read out in reflective mode with a commercial flatbed scanner. Results: Among various degrees of a polynomial function, the best fit, which fulfilled the chosen criterion of 95% agreement between measured and reconstructed doses and simple equation criterion, was observed for third-degree polynomial. The fitting curve where the dose is the function of optical density (logMPV) was demonstrated to be more precise than the fitting curve based on MPV only. To minimize the difference between dose absorbed by the film and dose reconstructed from the fitting curve below 5% it is necessary to divide the calibration range of 0 – 8 Gy into two subranges for use in interventional radiology. This difference was set at a maximum level of 3.8% and 1.9% for the lowand high-dose range, respectively. Each series of films may have a slightly different calibration curve, especially for the low dose range. A deviation of up to 36% between two batches of Gafchromic film was observed. Conclusions: For the third-degree polynomial fitting function (one of the recommended in the literature) calibration should be done into low and high dose ranges and for each batch separately. A systematic error higher than 20% could be introduced when the fitting curve from one film batch is applied to the other film batch.

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An example of the application of Mössbauer spectroscopy for determination of concentration of iron in lyophilized brain tissue

Rzepecka P., Duda P., Giebułtowicz J., Sochacka M., Friedman A., Gałązka-Friedman J.

Nukleonika

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2017

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Vol. 62, No. 2

159--163

EN

Mössbauer spectroscopy is not routinely used for the determination of the concentration of iron. However, as this method does not need any pre-treatment of samples before measurements, it may be of extreme importance for the assessment of iron in samples, which can then be used for further investigations. Biological samples are a good example, however, as the concentrations of iron are very low in these, it is important to exclude possible artefacts from the background spectrum related to iron present in the counter and cryostat windows. The aim of this study was to compare two methods of determination of the amounts of iron in investigated sample: one, in which the background spectrum was subtracted from the sample spectrum measured, and the other, in which the obtained non-elaborated spectrum was fitted with two doublets – a doublet for the measured sample and a doublet for the background spectrum. Three samples containing known amounts of natural iron (400, 800 and 1600 µg) and a sample of lyophilized human brain tissue obtained from globus pallidus were assessed. Both methods led to the creation of a very good calibration curve with a correlation coefficient of 0.99. Although both methods gave similar results for the concentration of iron in the sample, the subtraction of the background spectrum had a significantly lower error of the final result.

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Siarka w bioetanolu – przyczyny rozbieżności wyników oznaczenia zawartości techniką fluorescencji UV i ICP-OES

Altkorn B.

Nafta-Gaz

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2017

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R. 73, nr 7

510--517

PL

Z praktyki laboratoryjnej INiG – PIB wynika, że w przypadku niektórych próbek handlowych bioetanoli, stosowanych jako biokomponent w benzynach silnikowych, oznaczenie zawartości siarki techniką ICP-OES oraz fluorescencji w nadfiolecie prowadzi do uzyskania wyników różniących się od siebie więcej niż o niepewność metody badania, zatem do wyników różnych. Rezultaty otrzymane techniką ICP-OES są wyższe od uzyskanych techniką fluorescencji UV. Przeprowadzono analizę przyczyn występowania tego zjawiska, biorąc pod uwagę rodzaj i ilość obecnych w bioetanolu związków siarki oraz źródła ich pochodzenia. Porównano metody i techniki analityczne stosowane w Europie i USA do oznaczania zawartości siarki w bioetanolu. Stwierdzono, że prawdopodobną przyczyną występowania różnic w poziomie zawartości siarki oznaczonej techniką fluorescencji w nadfiolecie i ICP-OES jest niewłaściwie dobrana substancja wzorcowa w metodyce EN 15837 (technika ICP-OES), co powoduje zawyżenie wyników. Drugą przyczyną jest jednoczesna obecność w bioetanolu siarki w postaci związków organicznych (np. siarczków i/lub heterocyklicznych związków aromatycznych zawierających atom siarki) i nieorganicznych – siarczanów. Zmiana substancji wzorcowej w technice ICP-OES z nieorganicznych jonów siarczanowych na heterocykliczny związek siarki, np. dibenzotiofen lub tionaften, pozwoliłaby prawdopodobnie na otrzymanie miarodajnych, poprawnych wyników analitycznych przy oznaczaniu zawartości siarki, występującej w bioetanolu głównie w postaci siarczków.

EN

From the laboratory practice of the Oil and Gas Institute – National Research Institute, it follows that for some commercial samples of bioethanol (fuel ethanol), determination of the sulfur content using for ICP-OES and UV fluorescence leads to results that differ from each other by more than the uncertainty of the test method, therefore different results. The results obtained for ICP-OES are higher when compared to fluorescence UV technique. An analysis of the causes of this phenomenon was carried out, taking into account the type and the amount of sulfur compounds present in the bioethanol and their source of origin. Methods and analytical techniques used in Europe and USA for the determination of the sulfur content in bioethanol were compared. It was found, that the probable cause of the differences in the level of sulfur content, determined by technique UV and ICP-OES is the improperly chosen reference substance in the methodology EN 15837 (technique ICP-OES), which tends to bias the results. The second reason is the simultaneous presence of sulfur in the bioethanol as organic sulfur compounds (eg. sulfide and/or heterocyclic aromatic compounds containing sulfur) and inorganic compounds – sulphates. Changing the standard substance in technique ICP-OES from inorganic sulphate ions to heterocyclic sulfur compound, for example dibenzothiophene or thionaphthene, would probably allow to obtain reliable analytical results for the determination of sulfur present in bioethanol, occurring in bioethanol mainly in the form of sulfides.

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Sensor Calibration Design Based on D-Optimality Criterion

Hajiyev C.

Metrology and Measurement Systems

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2016

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Vol. 23, nr 3

413--424

EN

In this study, a procedure for optimal selection of measurement points using the D-optimality criterion to find the best calibration curves of measurement sensors is proposed. The coefficients of calibration curve are evaluated by applying the classical Least Squares Method (LSM). As an example, the problem of optimal selection for standard pressure setters when calibrating a differential pressure sensor is solved. The values obtained from the D-optimum measurement points for calibration of the differential pressure sensor are compared with those from actual experiments. Comparison of the calibration errors corresponding to the D-optimal, A-optimal and Equidistant calibration curves is done.

8

Szacowanie niepewności pomiarowej w woltamperometrii

Mucha P., Sordoń W., Jakubowska M.

Analit

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2016

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Nr 2

71--82

PL

Według międzynarodowego słownika terminów metrologicznych, niepewność jest parametrem, który ściśle powiązany jest z ostatecznym wynikiem pomiaru i stanowi rozrzut względem wartości, jaka może być przyporządkowana konkretnej wielkości mierzonej. W pracy podjęto próbę ukazania strategii umożliwiającej wyznaczenie niepewności pomiaru woltamperometrycznego w oparciu o wyznaczenie niepewności stężenia wzorca kwasu ferulowego oraz kolejnych jego dodatków. Aby jeszcze dobitniej wykazać słuszność prowadzonych w pracy działań, dla uzyskanych wyników w programie MATLAB wykreślono krzywą kalibracyjną uwzględniającą typową niepewność prądową oraz krzywą ujmującą niepewność dla obu osi układu współrzędnych wraz z niepewnością dotowanego wzorca. Ponadto dla wybranych krzywych kalibracyjnych sprawdzono jak sposób odjęcia tła oraz rodzaj dopasowywanej linii bazowej wpływa na miarodajność krzywej kalibracyjnej.

EN

According to the ISO Guide, uncertainty is a parameter closely linked to the final outcome of measurement and to scattering of value that can be assigned to particular measurand. In this master thesis the strategy enabling determination of the measurement uncertainty associated to voltammetric measurement on the basis of determination of uncertainty of concentration of ferulic acid and its further additions is discussed. To demonstrate the validity of operations, for the results obtained in MATLAB, the calibration curve representing typical uncertainty of the current curve was plotted, as well as the curve representing uncertainty of both axes of the coordinate system, along with uncertainty of ferulic acid standard. In addition to the selected calibration curves it was checked how background subtraction and the type of baseline matching affects the reliability of the calibration curve.

9

Krzywa kalibracyjna krok po kroku

Nyrek K

LAB Laboratoria, Aparatura, Badania

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2014

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R. 19, nr 4

24--26

PL

Większość laboratoriów wykorzystuje krzywą kalibracyjną do codziennych pomiarów. Jest więc rzeczą naturalną, że przy tej okazji pojawia się szereg pytań odnośnie wyznaczania jej parametrów i sposobów sprawdzania jakości uzyskanej krzywej. Dlatego też, celem niniejszego artykułu jest przeprowadzenie czytelnika, przez wyznaczenie parametrów krzywej kalibracyjnej, a następnie sprawdzenie jej jakości.

10

Generalized approach to the choice of lubricant for hot isothermal forging of aluminium alloys

Petrov P.

Computer Methods in Materials Science

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2007

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Vol. 7, No. 1

106-111

EN

Isothermal forging is a technological process of hot bulk forging which is related to definite temperatures of dies and workpiece heating. Usually, isothermal forging is performed with the help of low-velocity forging equipment like hydraulic presses. So that the maximum value of die velocity is not more than 5 mm/s. To avoid die chilling the dies are heated up to approximately the same temperature as the workpiece. In this range, conventional die materials for hot bulk forging cannot undergo the significant loss of strength or hardness. So, special tool materials should be applied for dies production. The development of any technological process of bulk forging and namely isothermal one requires the solution of the following tasks: 1) choose the forging method or forming process (forging with/without flash); 2) design a forging part in accordance with a machined part; 3) determine the necessary amount of forging operations; 4) determine the size and shape of workpiece; 5) design forging dies; 6) choose the suitable press-forging equipment and lubrication; 7) try out experimentally the developed technology and if necessary make some modifications. In most cases, the application of forging in isothermal conditions means the production of a near net shape forging. Design of near net shape forging part according to a machined one can be carried out with the help of some recommendations which are based on practical experience of forging. One of the technological parameters which has a strong influence the quality of a near net shape forging is the type of lubricant. The choice of a lubricant for isothermal forging is major task, especially in case of aluminium alloys deformation. The isothermal forging of Al-alloys belongs to the forging processes in which the slight increase in contact friction affects on the material flow, the quality of the forgings and gives rise to increase in deformation load. The efficiency of any lubricant can be estimated by at least three criteria: 1) the lubricant should have good tribological properties; 2) the lubricant should have good heat-shielding properties; 3) the lubricant should produce little or no smoke. So that, some laboratory tests should be carried out. The present paper is a generalization of the results which were obtained for the last three years. It implies the investigations of interfacial friction in hot isothermal deformation of such non-ferrous material as Al-Mn, Al-Mg, Al-Cu-Mg and Al-Cu-Mg-Fe-Ni aluminium alloys. Two completely different types of lubricant were used for the research on. Wide range of temperatures was observed. Moreover, the hydraulic press and screw press were used for the deformation of the samples of aluminium alloys under study. The tribological properties of lubricants were determined with the help of ring upsetting technique. The sets of calibration curves were drawn. Each set of calibration curves corresponds to the definite type of aluminium alloy as well as definite conditions of deformation. Some practical recommendations were given.

PL

Uogólnienie wyników uzyskanych na przestrzeni czterech nich lat (Petrov et al., 2003, 2004, 2005, 2006) z zakresu i wpływu tarcia międzyfazowego podczas odkształcenia na gorąco jest tematem niniejszej publikacji. W pracy analizowano materiały nieżelazne na bazie aluminium: Al-Mn (AA3003), Al-Mg (A95456), Al-Cu-Mg (AA2024) i Al-Cu-Mg-Fe-Ni (A92618). Analizę prowadzono dla szerokiego zakresu temperatur i dwóch różnych smarów z wykorzystaniem prasy hydraulicznej. Własności trybologiczne wykorzystanych smarów określono bazując na wynikach spęczania pierścieni. W pracy wykreślono krzywe wzorcowe odpowiadające konkretnym warunkom odkształcenia i danemu stopowi Al. Zamieszczono również uwagi praktyczne.

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Chronological study of archaeological sites and environmental change around 2600 BP in the Eurasian steppe belt (Uyuk Valley, Tuva Republic)

Zaitseva G. I., Chugunov K. V., Bokovenko N. A., Dergachev V. I., Dirksen V. G., Van Geel B., Koulkova M. A., Lebedeva L. M., Sementsov A. A., Plicht J. van der, Scott E. M., Vasiliev S. S., Lokhov K. I., Bourova N.

Geochronometria

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2005

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Vol. 24

97-107

EN

The main attention of the article presented focuses on the connection between the development of archaeological cultures and environmental changes during the 9th -4th centuries BC (2700-2400 BP). Environmental changes around 2600 BP can be observed by the character of the radiocarbon calibration curve. The region under study is the Uyuk depression in the Tuva Republic which is the part of the Eurasian steppe belt. To reconstruct environmental changes pollen and geochemical analyses of the lake deposits from the Uyuk depression were used. The main feature that made this territory more attractive for settling, is the humidity that promoted nomadic economy. The chronology of the archaeological sites corresponds to a period with a complicated shape of the calibration curve, and a special approach (wiggle-matching dating) is required. The famous Scythian time monuments Arzhan-1 and Arzhan-2 are located in this region and the wiggle matching method was used to establish the time of their construction. The Arzhan-1 is the oldest among the Scythian time monuments of all Eurasia. The chronology of other Scythian time monuments located in the western and eastern neighbouring territories of Tuva is considered and compared.