• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.71-77
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• 2021

An impeller identification technique that is essential for adding viscosity measurement functions to overhead stirrers is presented in this study. Previous studies have revealed that using magnets facing the same poles arranged in a row can aid in distinguishing the types of impellers by detecting the number of magnets in a non-contact manner. However, as these previous studies measured the magnetic fields using analog Hall sensors, a converting circuit for the digital signals is required that can interface with the MCU. In this study, it was demonstrated that the number of magnets can be distinguished without using a separate conversion circuit by using a Hall sensor with a digital output. Owing to the unique hysteresis characteristics of digital Hall sensors, it was confirmed through experiments that the complex and diverse outputs appear depending on the direction of the magnetic field, the arrangement of magnetic poles, and the moving direction of the magnet. The measurement of the magnetic field showed that an edge signal equal to the number of magnets inserted into the impeller was detected when the radial direction was used, and the south pole was first approached.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.30-37
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• 2000

This study was to analyze the chamical components of the pollens of Pinus rigida and P. koraensis and to investigate the optimal conditions for pollen pulverization. The results are as follow: (1) The contents of moisture, crude ash, crude protein, crude fat, crude filber and carbohydrate in the pollen of P. rigida were 9.9%, 2.5%, 13.1% 2.9% 7.5% 64.1% respectively, while those of P. koraiensis were 9.8%, 2.1%, 11.1% 2.8% 8.1% 66.1% respectively. All the contents of P. rigida and P. koraiensis were much higher than those of general crop grains. (2) Eighteen different amino acids were detected in the pollen of P. rigida and P. koraiensis. Among them, ten essential amino acids were indentified, which showed high nutritions values. (3) The contents of vitamin A, B1, B2, C, and E in the pollen of P. rigida were 8.7 mg, 10.1 mg, 15.9 mg, 32.9 mg, 1.9 mg, respectively, while those of in the pollen of P. koraiensis were 7.9 mg, 9.7 mg, 14.5 mg, 34.2 mg, and 2.5 mg respectively. Vitamin C among them was abundant. (4)When the pollen grains of P. prigida was pulverized for 50minutes at 5,000rpm and P. koraiensis for 40 minutes at 5,000rpm by Overhead stirrer, the 100% of pollen was pulverized.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.52-57
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• 2019

To develop a stirring device that can automatically measure the viscosity of a fluid, the impeller type of the device must be recognized without making contact. In this study, we propose a method to discriminate the type of impellers using the changes in the magnetic field. Permanent magnets are inserted into a hollow hole of the impellers, and the change of the magnetic field is measured by a hall sensor. All experimental results are compared with the FEM analysis results. The results show that with the increase in diameter and length of the magnet inserted into the impeller, the magnitude of the magnetic flux density increases. The magnetic field is more sensitive to the change in the magnet diameter than to the change in magnet length. In order to reduce the machining costs, however, it is advantageous to change the magnet length instead of the magnet diameter.

• Journal of Korea Foresty Energy
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• v.18 no.2
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• pp.47-54
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• 1999

This study was to analyze the chemical components of the pollens of Pinus densiflora S. et Z. and P. thunbergii Parl. and to investigate the optimal conditions for pollen pulverization. The results were as follow : (1) The contents of moisture, crude ash, crude protein, crude fat, crude filber and carbohydrate in the pollen of P. densiflora were 9.8%, 2.3%, 11.9%, 2.9%, 7.7%, and 65.4%, respectively, while those of P. thunbergii were 10.5%, 2.2%, 13.5%, 3.5%, 8.5% and 61.8%, respectively. All the contents of P. densiflora and P.thunbergii were much higher than those general crop grains. (2) The pollen of Pinus densiflora and P. thunbergii eighteen different amino acids were detected in. Among them, ten esssential amino acids were identified, which showed high nutrition values. (3) The contents of vitamins A, B1, B2, C and E in the pollen of P. densiflora were 7.9mg, 8.7mg, 19.2mg, 31.5mg and 2.0mg, respectively, while those in the pollen of P. thunbergii were 8.5mg, 9.4mg, 15.7mg, 35.3mg, and 1.8mg respectively. Vitamin C among them was abundant. (4) When the pollen grains of P. densiflora were pilverized for 40 minutes at 5,000rpm and P. thunbergii, for 50 minutes at 5,000rpm by overhead stirrer, the 100% of pollen pulverization was possible.