A manually controlled TDR soil moisture meter operating with 300 ps rise-time needle pulse

Malicki, M. A.; Skierucha, Wojciech

doi:10.1007/bf00265691

Cited by 74 publications

(45 citation statements)

References 8 publications

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“…Into the studied sample, 8 two-rod miniprobes LP/ms (Easy Test) were placed for the monitoring of complex relative permittivity and electrical conductivity. The sensors are made of two 53 mm long parallel stainless steel rods, having 0.8 mm in diameter and separated by 5 mm [3]. The sphere of sensor's influence creates the cylinder having diameter about 7 mm and height about 60 mm, circumference around the rods of sensor.…”

Section: Methodsmentioning

confidence: 99%

Monitoring coupled moisture and salt transport using single vertical suction experiment

Pavlík

Mihulka

Pavlíková

et al. 2009

WIT Transactions on Modelling and Simulation

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A new method for simultaneous monitoring of coupled moisture and chloride ions transport is presented in the paper. The experiment is done in the conditions of one-sided 1.0 M NaCl solution vertical uptake into a sample of calcium silicate based material. In the experimental work, rod-shaped sample is used for the determination of moisture and chloride concentration profiles in simulated 1-D water and chloride solution transport. For the measurement, advanced Time Domain Reflectometry (TDR) sensors are used. The sensors allow for moisture content assessment on the basis of relative permittivity measurement and chloride concentration monitoring based on electrical conductivity measurement. On the basis of measured data, moisture and chloride concentration profiles are obtained. Experimentally determined chloride concentration profiles and moisture profiles are then used for identification of apparent chloride diffusion coefficient and moisture diffusivity on the basis of inverse analysis using a simple diffusion model. Finally, the calibration procedure of the applied measuring method is discussed and practical recommendations for application of the combined TDR/electrical conductivity sensors for monitoring of coupled moisture and salt solution transport are given.

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Section: Methodsmentioning

confidence: 99%

Monitoring coupled moisture and salt transport using single vertical suction experiment

Pavlík

Mihulka

Pavlíková

et al. 2009

WIT Transactions on Modelling and Simulation

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“…Therefore, it is possible to apply this technique to other studies, including analysis of spatial variability of soil moisture (Janik, 2008), determination of soil density (Durham, 2003), water conductivity and water capacity of construction materials (Pavlik et al, 2006;, determination of quality of biomass and biofuels (Paz et al, 2010), level assessment of liquid petrochemical materials in industrial applications (Piuzziet al, 2009), quality evaluation of vegetable oils (Cataldo et al, 2010). The Institute of Agrophysics PAS in Lublin has significant scientific achievements and practical implementations in this area (Malicki and Skierucha, 1989;Malicki and Walczak, 1999;Malicki et al, 1996;Skierucha, 2009;Skierucha et al, 2008a, b). TDR meters of soil moisture, salinity and temperature developed by the Institute of Agrophysics PAS in Lublin are used in many laboratories worldwide.…”

Section: Time-domain Reflectometry (Tdr)mentioning

confidence: 99%

Dielectric spectroscopy in agrophysics

Skierucha¹,

Wilczek²,

Szypłowska³

2012

International Agrophysics

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A b s t r a c t. The paper presents scientific foundation and some examples of agrophysical applications of dielectric spectroscopy techniques. The aim of agrophysics is to apply physical methods and techniques for studies of materials and processes which occur in agriculture. Dielectric spectroscopy, which describes the dielectric properties of a sample as a function of frequency, may be successfully used for examinations of properties of various materials. Possible test materials may include agrophysical objects such as soil, fruit, vegetables, intermediate and final products of the food industry, grain, oils, etc. Dielectric spectroscopy techniques enable non-destructive and non-invasive measurements of the agricultural materials, therefore providing tools for rapid evaluation of their water content and quality. There is a limited number of research in the field of dielectric spectroscopy of agricultural objects, which is caused by the relatively high cost of the respective measurement equipment. With the fast development of modern technology, especially in high frequency applications, dielectric spectroscopy has great potential of expansion in agrophysics, both in cognitive and utilitarian aspects.K e y w o r d s: agrophysics, dielectric spectroscopy, food quality INTRODUCTIONAgrophysics is a specialized scientific field derived from the branch of the agricultural sciences (Micha³ek, 2006). Its aim is to apply physical methods for studies of properties of materials and processes occurring in production and processing of crops and food of agricultural origin. Dielectric properties of all materials existing in Nature are dependent on their molecular structure. Specifically, they depend on the distribution of electric charges, which are either constantly embedded within the molecules or become temporarily induced on their surfaces. It is also known that the molecular structure of objects determine their physical and chemical properties. Therefore, one may suppose that the dielectric properties of mixtures of various molecules constituting a given material will uniquely identify it. It means that dielectric properties can successfully diversify physical and chemical properties of a tested material. This idea is presented in Fig. 1. The crucial point of the application of the dielectric spectroscopy measurement techniques in agrophysics is the utilization of their advantages for rapid and non-destructive assessment of the quality of the agricultural objects. It may be done by searching for dependencies between the dielectric properties and other physical and chemical properties of tested materials of agricultural origin.Behaviour of any material in the electric field is unique, because of the unique molecular structure of each material. On the other hand, physical and chemical properties of materials determine their quality, which in the case of food products is closely related to their commercial and nutritional value. Therefore, it is reasonable to assume that the dielectric properties, uniquely describing each...

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“…the relation between the water content of the medium and its dielectric permittivity is highly correlated for the majority of the porous media (Davis et al, 1977;Malicki & Skierucha, 1989;Topp et al, 1980), -the attenuation of the amplitude of electromagnetic wave traveling along the parallel transmission line inserted into the medium, measured from the amplitudes of the pulse before (U in ) and after (U out ) attenuation caused by the pulse travel twice a distance of the probe length, L ( Fig. 1) depends on its bulk electrical conductivity, EC b (Dalton et al, 1984):…”

Section: Boundary Conditionmentioning

confidence: 99%