نتایج جستجو برای: moisture measurement
تعداد نتایج: 478666 فیلتر نتایج به سال:
Sphagnum (spp.) is widely distributed in permafrost regions around the arctic and subarctic. The moisture content of the moss layer affects the thermal insulative capacity and preservation of permafrost. It also controls the growth and collapse history of palsas and other peat mounds, and is relevant, in general terms, to permafrost thaw (therrnokarst). In this study, we test and calibrate seve...
A brief history of cereal grain moisture measurement by sensing the electrical properties of grain is presented. The basic principles are also described for using radio-frequency (RF) and microwave dielectric properties, or permittivity, of grain for sensing moisture through their correlation with moisture content. The development of density-independent functions of the permittivity is explaine...
The electrical conductivity (EC) of soil is generally measured after soil extraction, so this method cannot represent the in situ EC of soil (e.g., EC of soils with different moisture contents) and therefore lacks comparability in some cases. Using a resistance measurement apparatus converted from a configuration of soil microbial fuel cell, the in situ soil EC was evaluated according to the Oh...
Dielectric-based methods were used to determine nondestructively and simultaneously bulk density and moisture content in shelled peanuts from measurement of their relative complex permittivity at microwave frequencies (7–12 GHz) and 24 C. The first method is based on direct relationships between the two components of the relative complex permittivity (dielectric constant and dielectric loss fac...
Permeation-tube moisture generators are used in industry as calibrated sources of water vapor and carrier gas mixtures. Measurements were made using three permeation-tube moisture generators of the type used in the semiconductor industry. This paper describes repeatability and reproducibility standard deviations in measurement of moisture concentration from such generators. Repeatability refers...
The oil/paper insulation system in a transformer degrades under various chemical, thermal and electromechanical stresses during its operation. Dielectric response measurements like the Return Voltage Measurement (RVM) and Polarisation and Depolarisation Current (PDC) measurement are currently being used for condition assessment of the insulation. In the current research project, the ageing cond...
A method for determining optimal parameters for a field-scale hydraulic conductivity function is presented and tested on soil moisture and matric potential data measured at several locations in a field drainage experiment. The change in moisture content over time at the individual locations is modeled using Richards’ equation, and an optimization for the hydraulic conductivity parameters is per...
This paper discusses a measurement principle for online moisture determination of wood pellets that is based on capacitive sensing. To ensure reliability and proper operation of the sensing device even under harsh industrial conditions, a robust principle based on a frequency hopping approach is required. Therefore, we investigate the impact of multiple carrier frequencies and analyze the frequ...
Introduction The stability of the paper machine short circulation, forming and press section are tightly connected. A new online measurement, IQInsight, now provides true instantaneous MD and CD profiles from the press section. This unique measurement device provides new possibilities for stabilizing and optimizing paper machines. The accurate and continuous moisture profile just after the pres...
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