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Wyszukujesz frazę "sensors" wg kryterium: Temat


Tytuł:
Explosives vapors–concentrating and optoelectronic detection
Autorzy:
Wojtas, J.
Rutecka, B.
Popiel, S.
Nawała, J.
Wesołowski, M.
Mikołajczyk, J.
Cudziło, S.
Bielecki, Z.
Powiązania:
https://bibliotekanauki.pl/articles/221395.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
explosives concentrator
explosive detection
optoelectronic sensors
CEAS sensors
Opis:
Detection of explosives vapors is an extremely difficult task. The sensitivity of currently constructed detectors is often insufficient. The paper presents a description of an explosive vapors concentrator that improves the detection limit of some explosives detectors. These detector s have been developed at the Institute of Optoelectronics. The concentrator is especially dedicated to operate with nitrogen oxide detectors. Preliminary measurements show that using the concentrator, the recorded amount of nitrogen dioxide released from a 0.5 ng sample of TNT increases by a factor of approx. 20. In the concentrator an induction heater is applied. Thanks to this and because of the miniaturization of the container with an adsorbing material (approx. 1 cm3), an extremely high rate of tempera ture growth is achieved (up to 500°C within approx. 25 s). The concentration process is controlled by a microcontroller. Compact construction and battery power supply provide a possibility of using the concentrator as a portable device.
Źródło:
Metrology and Measurement Systems; 2014, 21, 2; 177-190
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors
Autorzy:
Majewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/221201.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
polymer-based capacitive humidity sensors
low humidity measurement
humidity sensors modelling
Opis:
Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20-80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0-20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based capacitive humidity sensors, as well as of modelling the behaviour of that type of sensor. A logarithmic functional relationship between the relative humidity and the change of sensor output value at low humidity is suggested.
Źródło:
Metrology and Measurement Systems; 2017, 24, 4; 607-616
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of humidity on the stability of LTCC pressure sensors
Autorzy:
Santo Zarnik, M.
Belavic, D.
Powiązania:
https://bibliotekanauki.pl/articles/221696.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thick-film piezoresistive sensors
capacitive pressure sensors
offset stability
relative humidity
Opis:
LTCC-based pressure sensors are promising candidates for wet-wet applications in which the effect of the surrounding media on the sensor's characteristics is of key importance. The effect of humidity on the sensor's stability can be a problem, particularly in the case of capacitive sensors. A differential mode of operation can be a good solution, but manufacturing the appropriate sensing capacitors remains a major challenge. In the case of piezoresistive sensors the influence of humidity is less critical, but it still should be considered as an important parameter when designing sensors for low-pressure ranges. In this paper we discuss the stability of the sensors' offset characteristics, which was inspected closely using experimental and numerical analyses.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 133-140
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Approach to Measurement of Frequency Shifts Using the Principle of Rational Approximations
Autorzy:
Murrieta-Rico, F. N.
Petranovskii, V.
Sergiyenko, O. Y.
Hernandez-Balbuena, D.
Lindner, L.
Powiązania:
https://bibliotekanauki.pl/articles/220851.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
frequency measurement
rational approximations
sensors
Opis:
When a frequency domain sensor is under the effect of an input stimulus, there is a frequency shift at its output. One of the most important advantages of such sensors is their converting a physical input parameter into time variations. In consequence, changes of an input stimulus can be quantified very precisely, provided that a proper frequency counter/meter is used. Unfortunately, it is well known in the time-frequency metrology that if a higher accuracy in measurements is needed, a longer time for measuring is required. The principle of rational approximations is a method to measure a signal frequency. One of its main properties is that the time required for measuring decreases when the order of an unknown frequency increases. In particular, this work shows a new measurement technique, which is devoted to measuring the frequency shifts that occur in frequency domain sensors. The presented research result is a modification of the principle of rational approximations. In this work a mathematical analysis is presented, and the theory of this new measurement method is analysed in detail. As a result, a new formalism for frequency measurement is proposed, which improves resolution and reduces the measurement time.
Źródło:
Metrology and Measurement Systems; 2017, 24, 1; 45-56
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fibre-optic sensor for simultaneous measurement of thickness and refractive index of liquid layers
Autorzy:
Marzejon, Marcin
Karpienko, Katarzyna
Mazikowski, Adam
Jędrzejewska-Szczerska, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/220419.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fibre-optic
sensors
interferometry
Fabry-Pérot interferometer
Opis:
In this paper, we present a fibre-optic sensor for simultaneous measurement of refractive index and thickness of liquid layers. We designed an experimental low-coherence setup with two broadband light sources and an extrinsic fibre-optic Fabry-Pérot interferometer acting as the sensing head. We examined how the refractive index of a liquid film and its thickness affect spectrum at the output of a fibre-optic interferometer. We performed a series of experiments using two light sources and only one sensing head. The spectra were collected in ranges of 1220-1340 nm and 1500-1640 nm. The obtained results show that using two spectra recorded simultaneously for two wavelength ranges enables to determine thickness in a range of 50-500 μm, and refractive index of a liquid film in a range of 1.00-1.41 RIU using only one sensing head.
Źródło:
Metrology and Measurement Systems; 2019, 26, 3; 561-568
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Fibre Bending on Polarization-Dependent Twist Sensor Based on Tilted Bragg Grating
Autorzy:
Harasim, D.
Powiązania:
https://bibliotekanauki.pl/articles/221279.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optoelectronic sensors
tilted bragg grating
sensing technology
Opis:
This paper presents an experimental study on influence of input light polarization on the spectral characteristics of a fibre twist sensor based on Tilted Fiber Bragg Grating (TFBG) with simultaneous application of bending to an optical fibre. The application of proposed measurement stand could provide the ability of transforming the bending to a displacement. The twist measurement was performed by tuning of the sensor illuminating light polarization angle. The spectral parameters of selected cladding mode which are sensitive to the rotation of input light polarization angle have been shown. This paper shows the characteristics of transmittivity and wavelength shift for an incident high-order cladding mode measured with different curvatures of fibre. The dependency of selected cladding mode spectral parameters related with the twist measurement on the influence of temporary bending has been shown. The measurements were performed for two positions of sensing structure refractive index perturbations in relation to the bending direction plane. The experimental results show that the direction of TFBG structure bending has a small influence on the stability of spectral parameters characteristic for twist measurement, assuming that the bending direction is fixed while measurement.
Źródło:
Metrology and Measurement Systems; 2017, 24, 3; 577-584
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensors and systems for the detection of explosive devices - an overview
Autorzy:
Bielecki, Z.
Janucki, J.
Kawalec, A.
Mikołajczyk, J.
Pałka, N.
Pasternak, M.
Pustelny, T.
Stacewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/221624.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
explosive device sensors
detection of explosive materials
Opis:
The paper presents analyses of current research projects connected with explosive material sensors. Sensors are described assigned to X and γ radiation, optical radiation sensors, as well as detectors applied in gas chromatography, electrochemical and chemical sensors. Furthermore, neutron techniques and magnetic resonance devices were analyzed. Special attention was drawn to optoelectronic sensors of explosive devices.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 3-28
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Leak Detection in Waterworks: Comparison Between STFT and FFT with an Overcoming of Limitations
Autorzy:
Lay-Ekuakille, A.
Griffo, G.
Visconti, P.
Primiceri, P.
Velazquez, R.
Powiązania:
https://bibliotekanauki.pl/articles/220719.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
uncertainty
measurements
magnetic sensors
leak detection in pipelines
regularization
Opis:
Detection of leakages in pipelines is a matter of continuous research because of the basic importance for a waterworks system is finding the point of the pipeline where a leak is located and - in some cases - a nature of the leak. There are specific difficulties in finding leaks by using spectral analysis techniques like FFT (Fast Fourier Transform), STFT (Short Term Fourier Transform), etc. These difficulties arise especially in complicated pipeline configurations, e.g. a zigzag one. This research focuses on the results of a new algorithm based on FFT and comparing them with a developed STFT technique. Even if other techniques are used, they are costly and difficult to be managed. Moreover, a constraint in the leak detection is the pipeline diameter because it influences accuracy of the adopted algorithm. FFT and STFT are not fully adequate for complex configurations dealt with in this paper, since they produce ill-posed problems with an increasing uncertainty. Therefore, an improved Tikhonov technique has been implemented to reinforce FFT and STFT for complex configurations of pipelines. Hence, the proposed algorithm overcomes the aforementioned difficulties due to applying a linear algebraic approach.
Źródło:
Metrology and Measurement Systems; 2017, 24, 4; 631-644
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the NO2 concentration prediction possibility based on static and dynamic responses of TGS sensors at changing humidity levels
Autorzy:
Kalinowski, Paweł
Woźniak, Łukasz
Jasiński, Grzegorz
Jasiński, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/220989.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
TGS sensors
partial least squares
nitrogen dioxide
dynamic measurements
Opis:
The commercially available metal-oxide TGS sensors are widely used in many applications due to the fact that they are inexpensive and considered to be reliable. However, they are partially selective and their responses are influenced by various factors, e.g. temperature or humidity level. Therefore, it is important to design a proper analysis system of the sensor responses. In this paper, the results of examinations of eight commercial TGS sensors combined in an array and measured over a period of a few months for the purpose of prediction of nitrogen dioxide concentration are presented. The measurements were performed at different relative humidity levels. PLS regression was employed as a method of quantitative analysis of the obtained sensor responses. The results of NO2 concentration prediction based on static and dynamic responses of sensors are compared. It is demonstrated that it is possible to predict the nitrogen dioxide concentration despite the influence of humidity.
Źródło:
Metrology and Measurement Systems; 2020, 27, 1; 167-179
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasi-distributed network of low-coherence fiber-optic Fabry-Pérot sensors with cavity length-based addressing
Autorzy:
Karpienko, Katarzyna
Marzejon, Marcin J.
Mazikowski, Adam
Pluciński, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/1849131.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fabry-Pérot interferometer
sensors network
fiber-optics sensor
interferometry
Opis:
Distributed measurement often relies on sensor networks. In this paper, we present the construction of low-coherence fiber-optic Fabry-Pérot sensors connected into a quasi-distributed network. We discuss the mechanism of spectrum modulation in this type of sensor and the constraints of assembly of such sensors in the network. Particular attention was paid to separate the signals from individual sensors which can be achieved by cavity length-based addressing. We designed and built a laboratory model of a temperature sensors network. The employed sensors are low-coherence Fabry-Pérot interferometric sensors in a fiber-optics configuration. The extrinsic sensor cavity utilizes the thermal expansion of ceramics, and the sensors are addressed by the different lengths of the cavities. The obtained test results show that the signal components from each sensor can be successfully separated, and the number of sensors could be expanded depending on the FWHM of the light source.
Źródło:
Metrology and Measurement Systems; 2021, 28, 2; 289-305
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving the accuracy of the NDIR-based CO2 sensor for breath analysis
Autorzy:
Prokopiuk, Artur
Bielecki, Zbigniew
Wojtas, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/2052156.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
NDIR
CO2 sensors
breath analysis
absorption spectroscopy
Opis:
The paper presents an analysis and practical study of the temperature and pressure influence on a non-dispersive infrared (NDIR) sensor for measuring the concentration of carbon dioxide in human breath. This sensor is used for monitoring patients’ carbon dioxide (CO2) in the exhaled air. High precision and accuracy of CO2 concentration measurements are essential in air sampling systems for breath analysers. They, however, require an analysis of the influence of the human exhaled air pressure and temperature on the NDIR CO2 sensor. Therefore, analyses of the changes in concentration were carried out at a pressure from 986 mbar to 1027 mbar and a temperature from 20°C to 36°C. Finally, corresponding correction coefficients were determined which allow to reduce the relative uncertainty of CO2 sensor measurements results from 19% to below 5%.
Źródło:
Metrology and Measurement Systems; 2021, 28, 4; 803-812
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exhaled breath analysis by resistive gas sensors
Autorzy:
Chludziński, Tomasz
Kwiatkowski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/221713.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistive gas sensors
data processing
exhaled breath analysis
Opis:
Breath analysis has attracted human beings for centuries. It was one of the simplest methods to detect various diseases by using human smell sense only. Advances in technology enable to use more reliable and standardized methods, based on different gas sensing systems. Breath analysis requires the detection of volatile organic compounds (VOCs) of the concentrations below individual ppm (parts per million). Therefore, advanced detection methods have been proposed. Some of these methods use expensive and bulky equipment (e.g. optical sensors, mass spectrometry - MS), and require time-consuming analysis. Less accurate, but much cheaper, are resistive gas sensors. These sensors use porous materials and adsorption-desorption processes, determining their physical parameters. We consider the problems of applying resistive gas sensors to breath analysis. Recent advances were underlined, showing that these economical gas sensor scan be efficiently employed to analyse breath samples. General problems of applying resistive gas sensors are considered and illustrated with examples, predominantly related to commercial sensors and their long-term performance. A setup for collection of breath samples is considered and presented to point out the crucial parts and problematic issues.
Źródło:
Metrology and Measurement Systems; 2020, 27, 1; 81-89
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical foundations determining spectral characteristics measured in Bragg gratings subjected to bending
Autorzy:
Kisała, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/2173892.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optical fibers
tilted fiber Bragg grating
bending sensors
Opis:
The article presents an analysis of the impact of bending optical fibers with tilted Bragg gratings on their spectral parameters. This article proves that it is possible to a choose TFBG cladding mode and the optical spectrum range related to it that allows the best metrological properties to be obtained when measuring bend. The results contained in the paper explain why the minima in the spectral characteristics, corresponding only to some cladding modes, change their shape during TFBG bending, which is important for application of Bragg gratings as bending sensors. It has been presented that in the case of TFBG we are able to aggregate the knowledge obtained during experiment to the form of a physical model of the fiber bending sensor.
Źródło:
Metrology and Measurement Systems; 2022, 29, 3; 573--584
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An embedded beamformer for a PID-based trajectory sensing for an autonomous vehicle
Autorzy:
Mvemba, P. K.
Lay-Ekuakille, A.
Kidiamboko, S.
Rahman, M. Z. U.
Powiązania:
https://bibliotekanauki.pl/articles/221802.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autonomous vehicle
beamforming
trajectory follower
ultrasonic obstacle detector
measurement
sensors
Opis:
Beamforming is an advanced signal processing technique used in sensor arrays for directional signal transmission or reception. The paper deals with a system based on an ultrasound transmitter and an array of receivers, to determine the distance to an obstacle by measuring the time of flight and - using the phase beamforming technique to process the output signals of receivers for finding the direction from which the reflected signal is received - locates the obstacle. The embedded beam-former interacts with a PID-based line follower robot to improve performance of the line follower navigation algorithm by detecting and avoiding obstacles. The PID (proportional-integral-derivative) algorithm is also typically used to control industrial processes. It calculates the difference between a measured value and a desired set of points, then attempts to minimize the error by adjusting the output. The overall navigation system combines a PID-based trajectory follower with a spatial-temporal filter (beamformer) that uses the output of an array of sensors to extract signals received from an obstacle in a particular direction in order to guide an autonomous vehicle or a robot along a safe path.
Źródło:
Metrology and Measurement Systems; 2018, 25, 3; 561-575
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new predictive filter for nonlinear alignment model of stationary MEMS inertial sensors
Autorzy:
Alhassan, Hassan Majed
Ghahremani, Nemat Allah
Powiązania:
https://bibliotekanauki.pl/articles/2052163.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
predictive filter
nonlinear alignment
model error
optimization
MEMS inertial sensors
Opis:
This paper proposes a new approach called the Predictive Kalman Filter (PKF) which predicts and compensates model errors of inertial sensors to improve the accuracy of static alignment without the use of external assistance. The uncertain model error is the main problem in the field as the Micro Electro Mechanical System (MEMS) inertial sensors have bias which change over time, and these errors are not all observable. The proposed filter determines an optimal equivalent model error by minimizing a quadratic penalty function without augmenting the system state space. The optimization procedure enables the filter to decrease both model uncertainty and external disturbances. The paper first presents the complete formulation of the proposed filter. Then, a nonlinear alignment model with a large misalignment angle is considered. Experimental results demonstrate that the new method improves the accuracy and rapidness of the alignment process as the convergence time is reduced from 550 s to 50 s, and the azimuth misalignment angle correctness is decreased from 52′′ ± 47′′ to 4′′ ± 0.02′′.
Źródło:
Metrology and Measurement Systems; 2021, 28, 4; 673-691
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł

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