Andrzej Wilczek - Academia.edu (original) (raw)
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Papers by Andrzej Wilczek
Scientific Reports, Aug 17, 2021
Proceedings, Mar 22, 2020
Materials
Rapeseed is one of the most important sources of vegetable oil worldwide. Knowledge of the dielec... more Rapeseed is one of the most important sources of vegetable oil worldwide. Knowledge of the dielectric properties of rapeseed may be beneficial for moisture content determination and the optimization of microwave treatment processes. The aim of this research was to examine the complex dielectric permittivity spectra of rapeseed of moisture content from 8.3% to 16.1%. The measurements were performed in the 20 MHz–3 GHz frequency range with the use of a vector network analyzer and a coaxial transmission-line cell. The real part of dielectric permittivity significantly depended on the water content of the seeds. The obtained spectra were modeled with the use of a three-pole Debye model with bulk electrical conductivity. Because the highest-frequency pole was found near the high-frequency measurement band limit, the spectra were additionally modeled with the use of an approximate ABC model with two in-band Debye poles. The determined model parameters were found to be highly dependent on ...
Proceedings of the 5th International Symposium on Sensor Science (I3S 2017), 2017
Naziemne pomiary wilgotności gleby są niezbędne do kalibracji i weryfikacji modeli wyznaczania wi... more Naziemne pomiary wilgotności gleby są niezbędne do kalibracji i weryfikacji modeli wyznaczania wilgotności wierzchniej warstwy gleby za pomocą zdjęć satelitarnych. Analiza długoterminowej zmienności czasowo-przestrzennej wilgotności gleby może bowiem ujawnić trendy w obiegu wody, związane ze zmianami klimatu i zmianami pokrycia terenu roślinnością. Stacje monitoringu wilgotności gleby są nadal nieliczne, a istniejące systemy nie są ujednolicone pod względem technik pomiarowych, formatu danych, dostępu, itp. Nowo powstała instytucja o nazwie International Soil Moisture Network (ISMN) ma służyć jako scentralizowana baza danych, dostępnych użytkownikom oraz jako próba standaryzacji informacji, odnoszących się do wilgotności gleby. Za pomocą przeglądarki internetowej zapewnia ona globalny dostęp do wyników pomiaru wilgotności gleby z istniejących stacji pomiarowych i pomiarów walidacyjnych w formie znormalizowanych i zharmonizowanych zbiorów danych. Obecnie ISMN zawiera dane z 16 sieci ...
The objective of the PROFILE TDT project is to develop a robust, low-cost profile probe with high... more The objective of the PROFILE TDT project is to develop a robust, low-cost profile probe with high accuracy for longtime observations of soil moisture, salinity and temperature e.g. for the agricultural sector. The probe works with a modified Time Domain Transmission Technique, which was invented by our cooperation partner the Bohdan Dobrzański Institute of Agrophysics. The contribution of the Technical University Berlin to the PROFILE TDT project is the construction of the probe body and the calibration of the measurement system. We will present our laboratory tests with the first prototype and our ongoing material experiments that will ensure a long lifetime of the probe. Furthermore we will give an outlook on upcoming experiments, including measurements under given conditions, calibration for different soil types and finally the in-field test-phase. Information about the sensing technique will be given by our polish cooperation partner, who will also be represented at the EGU.
Electromagnetic measurement of soil moisture and salinity can be carried out in many ways, includ... more Electromagnetic measurement of soil moisture and salinity can be carried out in many ways, including FDR and TDR methods. However, in both cases, due to the natural heterogeneity of the soil, knowledge of the sensitivity zone size of a given measurement method of the selected sensor is required. Dielectric measurement result is an average value in this particular volume. The presence of soil surface layer or another genetic level in the probe’s sensitivity zone is an interfering factor. Knowledge of the size and shape of the probe’s sensitivity zone avoids methodological errors during probe installation and minimizes measurement error. Moreover, calibration of the sensor should be done in such way that the reference material fill the entire volume of the sensitivity zone. This is important during field measurements where the volume of the tested material is not limited by the walls of the sample container. It is known that the sensitivity zone depends on the frequency of the measure...
Materials, 2020
This paper presents dielectric measurements of talc, glass beads, and their mixtures under differ... more This paper presents dielectric measurements of talc, glass beads, and their mixtures under different moisture and salinity levels. The measurements were conducted using a prototype seven-rod probe (15 mm long central rod) connected to a single port of vector network analyzer. The samples were moistened with distilled water and KCl solutions in order to obtain six different moisture content levels. The complex dielectric permittivity was determined from vector network analyzer reflection-coefficient measurements based on the open-water-liquid calibration procedure. Next, the fitting of volumetric water content–real part of dielectric permittivity calibration curves was performed for each material at selected frequencies, and the obtained relations were compared with well-known calibration equations. Additionally, a salinity index for the tested materials was calculated. It was concluded that pure talc is not an optimal material for the calibration and verification of dielectric metho...
Sensors, 2020
Soil volumetric water content (θ) is a parameter describing one of the most important factors con... more Soil volumetric water content (θ) is a parameter describing one of the most important factors conditioning proper plant growth. Monitoring soil moisture is of particular importance in the rational use of water resources for irrigation, especially during periods of water scarcity. This paper presents a method of measuring soil moisture in the vicinity of the plant root system by means of a probe designed to be mounted on a mobile device used for precise plant irrigation. Due to the specific field conditions of the measurement, the design of the probe was proposed as a monopole antenna. Electromagnetic simulations of the probe were carried out with Ansys HFSS software to optimise its dimensions. Then a prototype of the probe was manufactured to conduct laboratory measurements with the use of a vector network analyser (VNA) working in the 20 kHz to 8 GHz frequency range. The VNA analyser was configured to work in the time-domain reflectometry (TDR) mode. From measurements of the time d...
Sensors, 2019
Soil moisture is one of the most important soil parameters. Knowledge of volumetric water content... more Soil moisture is one of the most important soil parameters. Knowledge of volumetric water content (VWC) of the root zone as well as the VWC dynamics in the soil profile is especially important for agriculture. Monitoring VWC at several depths in the soil profile can be performed using several soil moisture sensors placed at various depths. However, the use of a profile probe is more convenient, because the installation of a single probe is less disturbing to the soil, as well as less laborious and more cost-effective. The objective of the paper is to present the design and performance of a novel profile probe working in the time-domain transmission mode (P-TDT probe) with emphasis put on the penetration depth and sensitivity zone. The performance of the probe was assessed with the use of finite element method (FEM) simulations in the frequency domain, transient simulations in the time domain and laboratory experiments with the use of a vector network analyzer (VNA) working in the 10...
Research in Agricultural Engineering, 2012
The study presents the project and partial implementation of a modern monitoring system for the m... more The study presents the project and partial implementation of a modern monitoring system for the measurement of soil physical parameters. It is provided with smart sensors equipped with signal conversion electronics, individual identification and communication means decreasing the complexity of the measurement system and also the measurement errors that can appear during analog signal transmission along the cables from the sensors to the measuring unit. The applied wireless communication system operates in the 433MHz ISM (Industrial, Scientific, Medical) licence free frequency band for transmission of commands and data between a remote PC compatible computer (Master unit) and the smart sensors (Slave units) in the distance of several hundred meters. The presented partial implementation of the system measures the temperature at several locations in the soil profile in field conditions and communicates with the host PC computer in wireless way. The developed hardware and software is in...
Sensors, 2019
This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequen... more This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR) measurements of soil water content in a well-defined sample volume. The probe directly measures the complex dielectric permittivity spectrum and for this purpose requires three calibration media: air, water, and ethanol. Firstly, electromagnetic simulations were used to study the influence of the diameter of a container on the sensitivity zone of the probe with respect to the measured calibration media and isopropanol as a verification liquid. Next, the probe was tested in three soils—sandy loam and two silt loams—with six water contents from air-dry to saturation. The conversion from S 11 parameters to complex dielectric permittivity from vector network analyzer (VNA) measurements was obtained using an open-ended liquid procedure. The simulation and measurement results for the real part of the isopropanol dielectric permittivity obtained from four container...
Sensors (Basel, Switzerland), Jan 4, 2018
The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed usi... more The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed using a multipole dielectric relaxation model, which assumes three active relaxation processes: primary α-process (water relaxation) and two secondary processes caused by solid-water-ion interactions α' (bound water relaxations), as well as β' (Maxwell-Wagner effect). The performance of two designs of the dielectric probe was compared: a classical coaxial open-ended probe (OE probe) and an open-ended probe with a prolonged central conductor in a form of an antenna (OE-A-probe). The OE-A probe increases the measurement volume and consequently extends the range of applications to other materials, like granulated agricultural products, soils, or liquid suspensions. However, its measurement frequency range is limited as compared to the OE probe because, above 1.5 GHz, the probe with the antenna generates higher propagation modes and the applied calibrations and calculations are not suff...
Journal of Geophysics and Engineering, 2017
Measurement Science and Technology, 2017
Measurement Science and Technology, 2016
Scientific Reports, Aug 17, 2021
Proceedings, Mar 22, 2020
Materials
Rapeseed is one of the most important sources of vegetable oil worldwide. Knowledge of the dielec... more Rapeseed is one of the most important sources of vegetable oil worldwide. Knowledge of the dielectric properties of rapeseed may be beneficial for moisture content determination and the optimization of microwave treatment processes. The aim of this research was to examine the complex dielectric permittivity spectra of rapeseed of moisture content from 8.3% to 16.1%. The measurements were performed in the 20 MHz–3 GHz frequency range with the use of a vector network analyzer and a coaxial transmission-line cell. The real part of dielectric permittivity significantly depended on the water content of the seeds. The obtained spectra were modeled with the use of a three-pole Debye model with bulk electrical conductivity. Because the highest-frequency pole was found near the high-frequency measurement band limit, the spectra were additionally modeled with the use of an approximate ABC model with two in-band Debye poles. The determined model parameters were found to be highly dependent on ...
Proceedings of the 5th International Symposium on Sensor Science (I3S 2017), 2017
Naziemne pomiary wilgotności gleby są niezbędne do kalibracji i weryfikacji modeli wyznaczania wi... more Naziemne pomiary wilgotności gleby są niezbędne do kalibracji i weryfikacji modeli wyznaczania wilgotności wierzchniej warstwy gleby za pomocą zdjęć satelitarnych. Analiza długoterminowej zmienności czasowo-przestrzennej wilgotności gleby może bowiem ujawnić trendy w obiegu wody, związane ze zmianami klimatu i zmianami pokrycia terenu roślinnością. Stacje monitoringu wilgotności gleby są nadal nieliczne, a istniejące systemy nie są ujednolicone pod względem technik pomiarowych, formatu danych, dostępu, itp. Nowo powstała instytucja o nazwie International Soil Moisture Network (ISMN) ma służyć jako scentralizowana baza danych, dostępnych użytkownikom oraz jako próba standaryzacji informacji, odnoszących się do wilgotności gleby. Za pomocą przeglądarki internetowej zapewnia ona globalny dostęp do wyników pomiaru wilgotności gleby z istniejących stacji pomiarowych i pomiarów walidacyjnych w formie znormalizowanych i zharmonizowanych zbiorów danych. Obecnie ISMN zawiera dane z 16 sieci ...
The objective of the PROFILE TDT project is to develop a robust, low-cost profile probe with high... more The objective of the PROFILE TDT project is to develop a robust, low-cost profile probe with high accuracy for longtime observations of soil moisture, salinity and temperature e.g. for the agricultural sector. The probe works with a modified Time Domain Transmission Technique, which was invented by our cooperation partner the Bohdan Dobrzański Institute of Agrophysics. The contribution of the Technical University Berlin to the PROFILE TDT project is the construction of the probe body and the calibration of the measurement system. We will present our laboratory tests with the first prototype and our ongoing material experiments that will ensure a long lifetime of the probe. Furthermore we will give an outlook on upcoming experiments, including measurements under given conditions, calibration for different soil types and finally the in-field test-phase. Information about the sensing technique will be given by our polish cooperation partner, who will also be represented at the EGU.
Electromagnetic measurement of soil moisture and salinity can be carried out in many ways, includ... more Electromagnetic measurement of soil moisture and salinity can be carried out in many ways, including FDR and TDR methods. However, in both cases, due to the natural heterogeneity of the soil, knowledge of the sensitivity zone size of a given measurement method of the selected sensor is required. Dielectric measurement result is an average value in this particular volume. The presence of soil surface layer or another genetic level in the probe’s sensitivity zone is an interfering factor. Knowledge of the size and shape of the probe’s sensitivity zone avoids methodological errors during probe installation and minimizes measurement error. Moreover, calibration of the sensor should be done in such way that the reference material fill the entire volume of the sensitivity zone. This is important during field measurements where the volume of the tested material is not limited by the walls of the sample container. It is known that the sensitivity zone depends on the frequency of the measure...
Materials, 2020
This paper presents dielectric measurements of talc, glass beads, and their mixtures under differ... more This paper presents dielectric measurements of talc, glass beads, and their mixtures under different moisture and salinity levels. The measurements were conducted using a prototype seven-rod probe (15 mm long central rod) connected to a single port of vector network analyzer. The samples were moistened with distilled water and KCl solutions in order to obtain six different moisture content levels. The complex dielectric permittivity was determined from vector network analyzer reflection-coefficient measurements based on the open-water-liquid calibration procedure. Next, the fitting of volumetric water content–real part of dielectric permittivity calibration curves was performed for each material at selected frequencies, and the obtained relations were compared with well-known calibration equations. Additionally, a salinity index for the tested materials was calculated. It was concluded that pure talc is not an optimal material for the calibration and verification of dielectric metho...
Sensors, 2020
Soil volumetric water content (θ) is a parameter describing one of the most important factors con... more Soil volumetric water content (θ) is a parameter describing one of the most important factors conditioning proper plant growth. Monitoring soil moisture is of particular importance in the rational use of water resources for irrigation, especially during periods of water scarcity. This paper presents a method of measuring soil moisture in the vicinity of the plant root system by means of a probe designed to be mounted on a mobile device used for precise plant irrigation. Due to the specific field conditions of the measurement, the design of the probe was proposed as a monopole antenna. Electromagnetic simulations of the probe were carried out with Ansys HFSS software to optimise its dimensions. Then a prototype of the probe was manufactured to conduct laboratory measurements with the use of a vector network analyser (VNA) working in the 20 kHz to 8 GHz frequency range. The VNA analyser was configured to work in the time-domain reflectometry (TDR) mode. From measurements of the time d...
Sensors, 2019
Soil moisture is one of the most important soil parameters. Knowledge of volumetric water content... more Soil moisture is one of the most important soil parameters. Knowledge of volumetric water content (VWC) of the root zone as well as the VWC dynamics in the soil profile is especially important for agriculture. Monitoring VWC at several depths in the soil profile can be performed using several soil moisture sensors placed at various depths. However, the use of a profile probe is more convenient, because the installation of a single probe is less disturbing to the soil, as well as less laborious and more cost-effective. The objective of the paper is to present the design and performance of a novel profile probe working in the time-domain transmission mode (P-TDT probe) with emphasis put on the penetration depth and sensitivity zone. The performance of the probe was assessed with the use of finite element method (FEM) simulations in the frequency domain, transient simulations in the time domain and laboratory experiments with the use of a vector network analyzer (VNA) working in the 10...
Research in Agricultural Engineering, 2012
The study presents the project and partial implementation of a modern monitoring system for the m... more The study presents the project and partial implementation of a modern monitoring system for the measurement of soil physical parameters. It is provided with smart sensors equipped with signal conversion electronics, individual identification and communication means decreasing the complexity of the measurement system and also the measurement errors that can appear during analog signal transmission along the cables from the sensors to the measuring unit. The applied wireless communication system operates in the 433MHz ISM (Industrial, Scientific, Medical) licence free frequency band for transmission of commands and data between a remote PC compatible computer (Master unit) and the smart sensors (Slave units) in the distance of several hundred meters. The presented partial implementation of the system measures the temperature at several locations in the soil profile in field conditions and communicates with the host PC computer in wireless way. The developed hardware and software is in...
Sensors, 2019
This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequen... more This paper presents a novel seven-rod sensor used for time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR) measurements of soil water content in a well-defined sample volume. The probe directly measures the complex dielectric permittivity spectrum and for this purpose requires three calibration media: air, water, and ethanol. Firstly, electromagnetic simulations were used to study the influence of the diameter of a container on the sensitivity zone of the probe with respect to the measured calibration media and isopropanol as a verification liquid. Next, the probe was tested in three soils—sandy loam and two silt loams—with six water contents from air-dry to saturation. The conversion from S 11 parameters to complex dielectric permittivity from vector network analyzer (VNA) measurements was obtained using an open-ended liquid procedure. The simulation and measurement results for the real part of the isopropanol dielectric permittivity obtained from four container...
Sensors (Basel, Switzerland), Jan 4, 2018
The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed usi... more The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed using a multipole dielectric relaxation model, which assumes three active relaxation processes: primary α-process (water relaxation) and two secondary processes caused by solid-water-ion interactions α' (bound water relaxations), as well as β' (Maxwell-Wagner effect). The performance of two designs of the dielectric probe was compared: a classical coaxial open-ended probe (OE probe) and an open-ended probe with a prolonged central conductor in a form of an antenna (OE-A-probe). The OE-A probe increases the measurement volume and consequently extends the range of applications to other materials, like granulated agricultural products, soils, or liquid suspensions. However, its measurement frequency range is limited as compared to the OE probe because, above 1.5 GHz, the probe with the antenna generates higher propagation modes and the applied calibrations and calculations are not suff...
Journal of Geophysics and Engineering, 2017
Measurement Science and Technology, 2017
Measurement Science and Technology, 2016