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Wyszukujesz frazę "open path" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
A local model and calibration set ensemble strategy for open-path FTIR gas measurement with varying temperature
Autorzy:
Cięszczyk, S.
Powiązania:
https://bibliotekanauki.pl/articles/220752.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ensemble methods
FTIR
open path
temperature variation
Opis:
Open-Path Fourier Transform Infrared OP-FTIR spectrometers are commonly used for the measurement of atmospheric pollutants and of gases in industrial processes. Spectral interpretation for the determination of gas concentrations is based on the HITRAN database line-by-line modeling method. This article describes algorithms used to model gas spectra and to determine gas concentration under variable temperatures. Integration of individual rotational lines has been used to reduce the impact of spectrometer functions on the comparison of both measured and synthetic modeled spectra. Carbon monoxide was used as an example. A new algorithm for gas concentration retrieval consisting of two ensemble methods is proposed. The first method uses an ensemble of local models based on linear and non-linear PLS (partial least square) regression algorithms, while the second is an ensemble of a calibration set built for different temperatures. It is possible to combine these methods to decrease the number of regression models in the first ensemble. These individual models are appropriate for specific measurement conditions specified by the ensemble of the calibration set. Model selection is based on comparison of gas spectra with values determined from each local model.
Źródło:
Metrology and Measurement Systems; 2013, 20, 3; 513-524
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A multi-band integrated virtual calibration-inversion method for open path FTIR spectrometry
Autorzy:
Cięszczyk, S.
Powiązania:
https://bibliotekanauki.pl/articles/221293.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FTIR
in situ spectroscopy
open path
process diagnostics
Opis:
This paper addresses problems arising from in situ measurement of gas content and temperature. Such measurements can be considered indirect. Transmittance or natural radiation of a gas is measured directly. The latter method (spectral radiation measurement) is often called spectral remote sensing. Its primary uses are in astronomy and in the measurement of atmospheric composition. In industrial processes, in situ spectroscopic measurements in the plant are often made with an open path Fourier Transform Infrared (FTIR) spectrometer. The main difficulty in this approach is related to the calibration process, which often cannot be carried out in the manner used in the laboratory. Spectral information can be obtained from open path spectroscopic measurements using mathematical modeling, and by solving the inverse problem. Determination of gas content based on spectral measurements requires comparison of the measured and modeled spectra. This paper proposes a method for the simultaneous use of multiple lines to determine the gas content. The integrated absorptions of many spectral lines permits calculation of the average band absorption. An inverse model based on neural networks is used to determine gas content based on mid-infrared spectra at variable temperatures.
Źródło:
Metrology and Measurement Systems; 2013, 20, 2; 287-298
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda analizy widm mierzonych z wykorzystaniem spektrometrów OP-FTIR w monitorowaniu powietrza atmosferycznego oraz gazów w procesach przemysłowych
Open Path FT-IR Spectra Analysis Method for Monitoring of Environment and Processes with Varying Conditions
Autorzy:
Cięszczyk, S.
Komada, P.
Akhmetova, A.
Mussabekova, A.
Powiązania:
https://bibliotekanauki.pl/articles/1817978.pdf
Data publikacji:
2016
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
otwarta ścieżka
FTIR
analiza widm
wpływ temperatury
open path
spectrum analysis
temperature influence
Opis:
Open-Path Fourier Transform Infrared (OP-FTIR) can be used for monitoring of atmospheric environment. The open path technique is based on the measurement of the absorption along the atmosphere path between radiation source and spectrometer. Measurement paths used in this method have a considerable length – from tens of meters to several kilometers. The main advantage of OP-FTIR spectrometry is the possibility of continuously and simultaneously measuring concentrations of multiple compounds. Unfortunately, quantitative analysis of the spectra of such measurements is a difficult issue due to the changing atmospheric conditions and overlapping of the absorption spectra of various components. Numerous algorithms used for the interpretation of the measured spectra have been proposed. They can be classified into methods using classical chemometric calibration and iterative algorithms. Classical Least Square CLS and Partial Least Square PLS are the most commonly used methods of OP-FTIR spectrometry. Iterative methods are based on comparing measured data with synthetic spectra, that is computational models of investigated optical path transmission. For this purpose, databases such as HITRAN are used. Transmission model must take into account not only the spectral characteristics of gases, but also the measuring instrument influence on the measured spectrum. As an example of modeling the spectra of NH3 and HCl gas are used. Modeling of gas spectra with different resolution is shown. Classical methods of building a chemometric calibration model require appropriate reference samples. This is usually associated with considerable cost and time-consuming calibration process. In addition, correct calibration requires maintaining the same conditions during the calibration, as in practical measurements. This is possible only in the case of laboratory measurements. In particular, it is necessary to maintain a constant temperature and pressure of examined substances. It is connected with changes in width and intensity of gas rotational lines. In classical spectroscopy, changing environmental conditions require new calibration measurements. In the open path spectroscopy, changes in conditions occur naturally along with the changes in the examined environment (object, process). If the measurement conditions in the environment differ from those in calibration measurements, significant errors in determining the content of the ingredients may appear. Greater changes in conditions may occur in a variety of chemical or physical processes. Sometimes it is not possible to perform measurements in conditions similar to those occurring in a particular industrial facility. In such cases, synthetic spectra may be used in two ways: in an iterative process to compare with measured spectra or to form a chemometric calibration models. In the latter case, the problem of changing conditions can be solved in several ways. The simplest method is to build separate calibration models for all conditions that can occur during the measurement. However, in order to use this method, it is necessary to measure the existing conditions and choose an appropriate local model. Another method is to correct the measured spectra and to adapt them to the standard conditions. The third option is to build global models. The spectra of all the conditions that may occur during the measurement are then used for building a calibration model. Then, the effect of temperature on the determination of gas content for local calibration models is investigated. Finally, a global calibration model insensitive to temperature changes in 10-40°C range is built.
Źródło:
Rocznik Ochrona Środowiska; 2016, Tom 18, cz. 2; 218-234
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Free-Space Optics Development
Autorzy:
Mikołajczyk, J.
Bielecki, Z.
Bugajski, M.
Piotrowski, J.
Wojtas, J.
Gawron, W.
Szabra, D.
Prokopiuk, A.
Powiązania:
https://bibliotekanauki.pl/articles/221245.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optical communications
open path laser communications
line of sight communications
free space optics
Opis:
The article presents state of work in technology of free-space optical communications (Free Space Optics - FSO). Both commercially available optical data links and their further development are described. The main elements and operation limiting factors of FSO systems have been identified. Additionally, analyses of FSO/RF hybrid systems application are included. The main aspects of LasBITer project related to such hybrid technology for security and defence applications are presented.
Źródło:
Metrology and Measurement Systems; 2017, 24, 4; 653-674
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A specific problem of mechanism synthesis
Autorzy:
Buśkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/955219.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
podnośnik
podajnik
teoria maszyn i mechanizmów
six-bar linkage
open path synthesis
feeder design
Opis:
A technique for path synthesis is employed to design a feeder for carrying products between two points. The feeder is assumed to be a one degree of freedom system of six links connected by means of revolute joints. The mathematical basis of the concept is presented. An exemplary solution is presented and discussed.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 3; 513-522
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Peak detection unit for Free-Space-Optics receiver
Autorzy:
Achtenberg, Krzysztof
Mikołajczyk, Janusz
Szabra, Dariusz
Prokopiuk, Artur
Bielecki, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/221334.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
peak detection
infrared receiver module for optical communications
open path laser communications
free space optics
quantum cascade laser
Opis:
The paper presents verification of a peak detection method cooperating with infrared radiation detector module applications. The work has been divided into parts including SPICE simulations and presentation of results obtained with the constructed prototype. The design of the peak detector dedicated to applications with very short pulses requires a different approach than that for standard solutions. It is mainly caused due to the ratio of pulse width and time period. In the described application this ratio is less than 10%. The paper shows testing of an analogue circuit which is capable to be inserted in these applications.
Źródło:
Metrology and Measurement Systems; 2019, 26, 2; 377-385
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Advanced open CNC system with in process tool path compensation
Autorzy:
Hascoet, J.-Y.
Rauch, M.
Powiązania:
https://bibliotekanauki.pl/articles/99609.pdf
Data publikacji:
2014
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
open NC controller
simulation,manufacturing
tool path
compensation
Opis:
Despite several technical advances over the last decade, CNC controlled manufacturing still bases upon outdated paradigms: manufacturing data are generated and transferred along a heterogeneous and divided CAD/CAM/CNC data chain. The role of the NC controller is limited to the execution of tool paths generated beforehand and the possibility of online tool path adaptation is not planned in legacy NC controllers. In contrast, practical observations make this legacy approach quite inappropriate in an industrial framework. Significant geometrical variability is sometimes observed both prior and after milling in parts that belong to the same batch. In that context, the integration of online tool path adaptation strategies appears to be essential. In this paper, a methodology for correcting the tool path in real-time thanks to measurements provided by a laser scanner moving with the tool is introduced. The resulting local information is used to approximate the workpiece exact geometry by using a POD (Prosper Orthogonal Decomposition) snapshot technique and to adjust the path in accordance. This method has the great advantage of taking into consideration geometrical features such as curvature, twist but also additional parameters whose impact on the tool path is significant (unexpected initial setup of the part for example). This method has been implemented on the advanced CNC programming platform of the laboratory, which hosts in particular a high speed machining centre equipped with an open NC controller.
Źródło:
Journal of Machine Engineering; 2014, 14, 3; 48-57
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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