• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.693-698
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• 2007

In general the distributed winding method is applied for induction motor in order to have the sinusoidal flux distribution. Recently the concentrated winding method is the interested technique so as to lower the material cost portion of copper coil. In the concentrated winding induction motor the harmonic flux and the torque deterioration by it would be occurred. To restrain ill effect of harmonic flux distribution by concentrated winding, the skew of rotor conduction bar is very important design variable. This study is focused on the optimal design of rotor bar's skew and winding turns for concentrated winding induction motor. In this study, the control method of harmonic parasitic torque in concentrated winding induction motor is proposed and validated its practicality through the experiment. As a result of this study, large skew angle which was not conventional in distributed winding was favorable in the concentrated winding induction motor. The concentrated winding induction motor which is designed per the proposed method of this study can be manufactured more cost effectively than conventional distributed winding.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.264-269
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• 2006

Basic rheological data of dandelion leaf concentrates were determined to predict processing aptitude and usefulness of dandelion leaf concentrates as functional food materials. Hot water and 70% ethanol extracts of dandelion leaves were concentrated at 5, 20, and 50 Brix, and their static and dynamic viscosities, and Arrhenius plots were investigated. Most concentrated dandelion leaves extracted with hot water and 70% ethanol showed flow behaviors close to Newtonian fluid based on power law model evaluation. Apparent viscosity of concentrated dandelion leaves extracted with hot water and 70% ethanol decreased with increasing temperature. Yield stresses of concentrated dandelion leaves extracted with hot water and 70% ethanol by Herschel-Bulkley model application were 0.020-0.641 and 0.017-0.079 Pa, respectively. Activation energies of concentrated dandelion leaves extracted with hot water and 70% ethanol were $2.102-32.669{\times}10^3$ and $1.657-5.382{\times}10^3\;J/mol{\cdot}kg$ with increasing concentration, respectively. Loss modulus (G") predominated over storage modulus (G') at all applied frequencies, showing typical flow behavior of low molecular solution. G' and G" of concentrated dandelion leaves extracted with hot water slowly increased with increasing frequency compared to those of concentrated dandelion leaves extracted with 70% ethanol.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.54-62
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• 2014

This study deals with the design and characteristics analysis on a linear synchronous motor (LSM) with a long stator and phase concentrated winding (PCW) to apply for a propulsion system such as a roller coaster for leisure facilities. First of all, the required propulsion force of LSM is computed and its design with double sided permanent magnets (PMs) and a phase concentrated winding is processed. The phase concentrated winding is composed of a module with each A, B, and C phase unlike an conventional concentrated winding (CW). It has an advantage of the installation and manufacture, compared to the conventional concentrated winding in the propulsion system for leisure facilities that have a long acceleration area and stator configuration placed on rail continuously. Thus, the design for the propulsion system and characteristics comparison between the phase concentrated winding and concentrated winding are carried out in this paper. Also, the analysis on dynamic characteristics is conducted to confirm the performance at operation.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.273-282
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• 2007

This study was carried out to compare the changes of nutrients, sensory and chemical properties of freeze-concentrated and evaporated milks during storage. For pasteurization, the freeze-concentrated milk containing 27% of total solid was treated with 150 rpm ozone for 5 min, and 99% of microflora was eliminated. Also, the activities of protease and lipase decreased 93.31% and 96.15%, respectively, and phosphatase showed negative activity. Total bacteria count was maintained below$2.0{\times}10^4$CFU/ml. During storage, TBA absorbance was lower in freeze-concentrated milk than that in the evaporated milk. The production of short-chain free fatty acids and free amino acids increased proportionally to the storage period in both samples. While the short-chain free fatty acid production was lower in the freeze-concentrated milk compared with that in the evaporated milk, the production of individual free amino acid was similar in both samples. In sensory evaluation, cooked flavor and color were much lower in the freeze-concentrated milk than that in the evaporated milk. Overall acceptability score was higher in the freeze-concentrated than the evaporated milk. Based on above results, ozone treatment for the freeze-concentrated milk pasteurization was positive at the elimination of microflora and enzyme inactivation. During storage, the freeze-concentrated sample minimized the change of color and TBA absorbance, the production of short-chain free fatty acid and vitamins than the evaporated milk. Therefore, the freeze-concentrated milk process in the present study resulted in the positive effect in minimizing nutrient loss and keeping quality of milk during storage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.8
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• pp.2516-2523
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• 1996

The equations of motion for rotating contilever beams with a concentrated mass loated in an arbitrary position are derived. For the modeling of the concentrated mass the Dirac delta function is used for the mass density function. Parametric studies are performed with five dimensionless variables ; natural frequencies, angular velocity, hub radius, concentrated mass, and the mass location. The concentrated mass, whereverit may locate, lowers the natural frequencies of a stationaly beam. However, when the beam rotates, the natural frequencies(if they increase or decrease) are dictated by the location of the concentrated mass.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.181-186
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• 1998

A modelling method for the vibration analysis of rotating cantilever plates with a concentrated mass is presented. The equations of motion for the rotating plates with a concentrated mass located in an arbitrary position are derived. For the modelling of the concentrated mass, a mass density Dirac delta function is used. The effects of concentrated mass and its location, angular speed, and hub radius of the rotating plate on the natural frequencies are studied. Particularly, mode shape variations due to some parameter variations are investigated.

• Journal of Theoretical and Applied Mechanics
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• v.1 no.1
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• pp.89-96
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• 1995

An analytical method is presented for predicting the effect of a local deviation in the form of a concentrated mass along a radial line on the free bending vibration characteristics of a nearly axisymmetric circular plate. The approach is based on the Rayleigh-Ritz method and the expression of local deviation of the concentrated radial mass as the variation of heaviside unit step function. The effects of the concentrated mass on the natural frequencies and mode shapes of the plate are predicted with a proposed nondimensional mass parameter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.6-13
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• 2001

The study was conducted to investigate the effect of the browning inhibitors such as PVPP(polyvinylpoly-pyrrolidone), A.A.(ascorbic acid) on nonezymatic browning factors [free sugar, total amino acid, organic acid, A.A., HMF (hydroxymethylfurfural)] and enzymatic browning factors [PRO (polyphenoloxidase) activity, polyphenol compounds] in concentrated apple juice during 90 days storage. Considering color value (L value, $\Delta$E), absorbance at 420 nm, concentrated apple juice during 90 days storage. Considering color the effect of browning inhibition. According to the storage period, the changes of nonenzymatic factors in concentrated apple juice added with browning inhibitors were similar to those in control (concentrated apple juice without browning inhibitors), which were the decreased of sucrose(0.24~0.35% at 90 days), the slight increase of glucose and fructose, the decrease of total amino acid (530.4~573.1 mg/10g at 90 days), same value of A.A. at 90 days (38.5~78.6 mg/100g), and the increase of HMF (27.8~30.6 mg/100g at 90 days). On the contrary, enzymatic browning factors were significantly inhibited in concentrated apple juice added with PVPP, judging from the slow increase of PRO activity and the significant decrease of initial value in polyphenol compounds (especially chlorogenic acid). These results suggest that PVPP plays an important role as enzymatic browning inhibitor, that is, a scavenger of polyphenol compounds by adsorption in concentrated apple juice.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.297-302
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• 2005

Physicochemical properties were compared between freeze concentrated and vacuum evaporated milk through colour, brix, viscosity, freezing point and pH measurement. Brix and viscosity in each concentrated milk significantly increased due to solute concentration(p<0.05), and there was not much difference between freeze concentrated and evaporative one. Brix results were numerically modeled with the logarithmic regression: Y=-33.460+18.4513 ${\cdot}$ ln(X), $R^2=0.9798$ and this model was fairly fit to predict the solute concentration in the middle of freeze concentration process. Freezing point significantly decreased according to concentration increment(p<0.05) and there was not the significant difference between freeze concentrated and evaporated one. Whereas, in colour and pH value, there were some differences between freeze concentrated and evaporative milk. Vacuum evaporated milk expressed higher discoloration comparing to freeze concentrated one. In pH values, evaporated milk showed the significantly decreased results comparing to freeze concentrated sample, whereas the pH value of freeze concentrated sample expressed the similar value to the reference milk.

• Food Science and Preservation
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• v.3 no.2
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• pp.121-129
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• 1996

Plum highlighted as a health food is needed to diversify the processed products because labor storage is big problem since the fruit was producted massively in June. The Plum was extracted by the pressing type extractor after washing, drying and removing the seed by seed separator. The crude extract was concentrated with stainless steel vessel at different temperature and stirring speed. This study was obtained as follows. The sugar content of fresh plum concentrated extract was 55.3~58.3$^{\circ}$Brix, and of the freezing plum concentrated extract was 75.5~70.3$^{\circ}$Brix. In color difference, the freezing plum concentrated extract was more deep black than fresh plum. In change patten of pH, it was decreased as concentration was proceed. The final pH was 2.3~2.2 in fresh plum, and 1.8~2.2 in freezing plum. The total acid content of fresh plum concentrated extract and the freezing plum was 45.4~47.8, 60.3~60.9%, respectively. The content of evaporation at 85$\pm$5$^{\circ}C$ was constant irrespective of stirring speed. The yield of extraction of fresh plum was higher than freezing plum. According to this results, the use of stainless vessel, 50rpm, which gave a highly qualified plum concentrated extract.