• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.5
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• pp.525-533
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• 1997

A nondestructive moisture measurement technique has been applied to improve the previous moisture measurement method in the building research. The experiment was done in free space using horns since it is the key element for continuous and non-destructive measurement. For this purpose a microwave bridge type analyzer at the frequency of 9.5 GHz was used to determine the moisture content of sands in the range of 1~12%. From this, the representative calibration curves were obtained. This shows that moisture measurement technique using microwave is applicabe to the measurement of moisture in non-metallic materials such as coal, pulp, foods, building materials, etc.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.63-69
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• 2012

Ready-mixed concrete(RMC) has been a major construction materials for infrastructures. However, RMC with poor quality is reported to be social issue since it directly user's safety and convenience. Because the properties of concrete as a construction material are greatly influenced by the variation of water content, to control water accurately is the most efficient method for the quality control in RMC industry. In this study, the automatic measurement technology of fine aggregate was developed by using the microwave moisture measurement. For the various conditions of fine aggregate such as moisture, temperature and pressure, the calibration curve of moisture measurement was obtained by using oven-dry method. From the infield and outfield test, it can be obtained that the accuracy of microwave moisture measurement is very high and the automatic system of microwave moisture measurement is very convenient and useful for quality control in RMC Industry.

• Journal of Biosystems Engineering
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• v.13 no.3
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• pp.52-58
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• 1988

This study was conducted to develop a grain moisture content measurement sensor for automatic control of rough rice drying by natural air. For the above objective, the electrod type sensor was designed and tested. The sensor was able to produce electrical resistance which changes with moisture content of grain. An A/D converter and a micro-computer wed for processing measurement data of sensor. The developed sensor satisfied most design requirements and the results of statistical analysis show that there it no difference between the measurement method of sensor developed and of the dry-oven. Using the developed sensor and measurement system, we are able to measure moisture content of rough rice automatically in drying by natural air.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.115-123
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• 2000

Characterizing the electromagnetic properties of concrete is essential to the enhancement of accuracy and reliability in nondestructive testing of concrete structures using electromagnetic techniques. To establish a data base for the properties of concrete, a measurement technique has been developed and a set of data has been obtained for the frequency range of 1~6 GHz. As moisture content is one of major contributing factors to determine permittivity of dielectric material, moisture content is varied during the measurement. An application of a measurement system which consists of open-ended coaxial probe and automatic network analyzer to concrete and mortar specimens is studied. For this, calibration techniques, size of specimens, and number of measurements necessary to obtain reliable data are investigated. From the measured data, it is shown that moisture content plays an important role to determine the permittivity of specimens. As the moisture content increases. The permittivity of specimens show tendency to approach the permittivity of water.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.85-99
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• 2022

Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.290.2-290.2
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• 2003

Skin Moisture is an important factor in skin health. Measurement of moisture content can provide diagnostic information on the condition of skin. In this study, a photo diode array type near infrared spectroscopy was used to determine skin moisture. Diffuse reflectance spectra were collected and transformed to absorbance using 1-nm stepsize over the wavelength range of 1100 nm to 2200 nm. (omitted)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.571-575
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• 2018

The moisture content of a coffee bean affects its permittivity, and changing the moisture content of a coffee bean changes the taste of the coffee. The variation in the moisture content of a coffee bean can be predicted by the change in frequency and reflection coefficient values with respect to the variation in the permittivity of the bean when it is placed on a patch antenna. In this study, a dual-band patch antenna is designed, which has a moisture measurement band of 3.8~4 GHz that can measure the moisture level of a material; the antenna has a Wi-Fi transmit and receive band of 2.45 GHz. Through simulations and measurements, this study proved that the level of return losses changed from 3.6 to 4 GHz when the moisture content of a coffee bean changed from 2 to 15%. The moisture levels of rice and other beans can be measured with the designed antenna, which can be applied to various applications.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.85-94
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• 1998

Due to relatively high permittivity of water in soils, we placed the soil condenser into soils to measure the soil moisture content. The soil condenser was made with two insulated iron sticks. The capacitance of the soil condenser was determined by the pulse period from RC type oscillation circuit and the highest voltage output accepting 10MHz pulse. After zero point adjustment, the measured relative capacitance percentage (RCS) to the standard condenser obtained by the oscillation circuit almost linearly correlated with the end depth of the sensor submerged in water. The RC type oscillation was disturbed by many sensor installed in a close distance in one place, presumably resulting in that the sensor sticks played as a interfering antennas generating or accepting electron waves from them. The temperature dependance of the output from the sensors could be corrected through experimentally determined revision function. Although lineal correlation was found between soil moisture and RCS, users should derive their own correlation function for every sensor to measure soil moisture, because the outputs were influenced by the installation depth and layout in the soil. The voltage type sensor responded inversely with soil moisture content and so was not suitable to the accurate measurement of soil moisture, but allows high economic benefit in various application such as simplified measurement of soil moisture and irrigation line control because of its low component count. The voltage type moisture sensor could be reinforced by relay controlling circuit to open and to close the solenoid valves respectively at optimal limits of the least and the most soil moisture according to user's adjustment.

• Journal of Biosystems Engineering
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• v.12 no.1
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• pp.39-44
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• 1987

Measurement methods of moisture content were compared with 7 dried vegetables (red pepper, onion, green onion, garlic, ginger, carrot and radish). The moisture contents of dried vegetables having different moisture contents were determined by atmospheric oven drying, infrared balance, vacuum oven and Karl Fisher methods. Vacuum oven and Karl Fisher methods gave the relatively agreed results and considered to give the accurate moisture content. Atmospheric oven drying and infrared balance methods resulted in higher moisture content than methods mentioned above, because of the thermal decomposition of solid. Calibration of the moisture data of atmospheric oven drying method into the vacuum oven data was undertaken. The thermodecomposable solid fraction was high in onion, radish, green onion and carrot, and was in the range of 8.0-11.7% of the total solid in these products.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.369-376
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• 2002

The dielectric properties of cereal grains such as short-grain rough rice, brown rice and barley with various moisture contents were determined by measuring the attenuation and phase shift of the microwave signal trough the grain samples at 9.5GHz. The microwave free-space transmission measurement system consisted of sample holder, horn antenna and network analyzer. Dielectric constant and loss factor of grain samples increased with moisture content and bulk density and agreed well with previous research results. Moisture density, which is defined as the product of moisture content and bulk density, was proposed as a bulk density and variety compensation factor. The technique for measurement of dielectric properties based on free-space transmission may be useful for other particulate materials.