• Journal of IKEEE
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• v.22 no.4
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• pp.1206-1209
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• 2018

Single-layer winding configuration in a 12-slot 10-pole Permanent Magnet Synchronous Motor (PMSM) has been adopting in electrical power steering (EPS) systems to get the high fault tolerance capability of the motor. However, the motor with single-layer winding has magnetic circuit saturations in the teeth, which deteriorates its performance. In this paper, we propose asymmetric teeth widths to get over the demerit, and analyze the effect of the teeth width ratio variations on the performances of the PMSM. As a result, we suggest the most valuable teeth width ratio for designing the PMSM with a single-layer winding configuration.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.58-65
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• 2018

The life span of the porcelain insulator was made to be 30 years, but currently many of the 154kV NGK porcelain insulators using in Korea are found to have passed the production life. Accidents caused by aged mechanical breakdown can lead to disruption of power supply in some areas, large economic losses, and casualties. Therefore, ultrasonic method, which is one of the non - destructive test methods, is applied as a method for evaluating the integrity of porcelain insulators. In this study, the experiment on the interface of cap was conducted and the difference between the energy difference and the attenuation coefficient of the reflected wave was derived according to the interface state of the steel - cement. The results of this study are expected to be used as the basic data of the ultrasonic testing to evaluate the interface condition of the porcelain insulator cap.

• International journal of steel structures
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• v.18 no.4
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• pp.1200-1209
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• 2018

In this study, a probabilistic framework of the damage assessment of pipelines subjected to extreme hazard scenario was developed to mitigate the risk and enhance design reliability. Nonlinear 3D finite element models of T-joint systems were developed based on experimental tests with respect to leakage detection of black iron piping systems, and a damage assessment analysis of the vulnerability of their components according to nominal pipe size, coupling type, and wall thickness under seismic wave propagations was performed. The analysis results showed the 2-inch schedule 40 threaded T-joint system to be more fragile than the others with respect to the nominal pipe sizes. As for the coupling types, the data indicated that the probability of failure of the threaded T-joint coupling was significantly higher than that of the grooved type. Finally, the seismic capacity of the schedule 40 wall thickness was weaker than that of schedule 10 in the 4-inch grooved coupling, due to the difference in the prohibition of energy dissipation. Therefore, this assessment can contribute to the damage detection and financial losses due to failure of the joint piping system in a liquid pipeline, prior to the decision-making.

• Economic and Environmental Geology
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• v.44 no.5
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• pp.359-372
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• 2011

TA26 seamount, which is located at south part of Tonga arc, occurs widely hydrothermal plume and is area that sampled hostrock, hydrothermal ore and hydrothermal alteration rock for this study. Hostrocks are basalt and basaltic andesite. Altered rocks by hydrothermal solution consists of plagioclase, pyroxene, pyrite, ilmenite, amorphous silica, barite, smectite, iron sulfates, Fe-Si sulfates and Fe silicates. Gains and losses of major, trace and rare earth elements during wallrock alteration suggest that $K_2O$(+0.04~+0.45 g), $SiO_2$(-6.52~+10.56 g), $H_2O$(-0.03~+6.04 g), $SO_4$(-0.46~+17.54 g), S(-0.46~+13.45 g), total S(-0.51~+16.93 g), Ba(-7.60~+185078.62 g), Sr(-36.18~+3033.08 g), Ag(+54.83 g), Au(+1467.49 g), As(-5.80~+1030.80 g), Cd(+249.78 g), Cu(-100.57~+1357.85 g), Pb(+4.91~+532.65 g), Sb(-0.32~+66.59 g), V(-113.58~+102.94 g) and Zn(-49.56~+14989.92 g) elements are enriched from hydrothermal solution. Therefore, gained(enriched) elements(($K_2O$, $H_2O$, $SO_4$, S, total S, Ba, Sr, Ag, Au, As, Cd, Cu, Pb, Sb, V, Zn) represent a potentially tools for exploration of sea-floor hydrothermal deposits from the Tonga arc.

• Journal of Nutrition and Health
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• v.39 no.7
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• pp.624-640
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• 2006

Dialysis patients are at risk of malnutrition not only because of losses of nutrients during peritoneal dialysis but also because of anorexia that results in inadequate nutrient intakes. The aim of this study was to estimate the nutritional status of 154 patients receiving continuous ambulatory peritoneal dialysis (CAPD), especially focused on protein-energy malnutrition and vitamin and mineral status. The mean age of the subjects was $5.12\;{\pm}\;12.4\;y$ with educational years of $12.3\;{\pm}\;0.4\;y$ for male and $9.6\;{\pm}\;0.4\;y$ for female. The mean duration of dialysis was $22.7\;{\pm}\;21.7\;mo$. The causes of renal failure included diabetes (32.7), chronic glomerulonephritis (15.0%), and hypertension (8.5%). The main complications associated with chronic renal failure were hypertension (86.1%), diabetes (35.4%) and liver disease (9.0%). The mean daily energy intake was $1216.8\;{\pm}\;457.3\;kcal$ and increased to $1509.2\;{\pm}\;457.2\;kcal$ when added with the energy from dextrose in dialysate. The latter was still much lower than estimated energy requirement but energy intake per kg of body weight (28.1 kcal/1 g) was within the range of that recommended for CAPD patients' diet therapy (25 - 30 kcal/kg). The average daily intake of protein was $49.2\;{\pm}\;25.1\;g$ with 37.6% of the patients showing their intakes less than Estimated Average Requirement. The average protein intake per kg of weight was 0.9 g/kg, which is less than that recommended for CAPD patients (1.2-1.5g/kg) with mean serum albumin level $3.2\;{\pm}\;0.5\;g/dl$. The proportion of the patients with dietary calcium intake less than EAR was 90.9%, but when added with supplementary calcium (phosphorus binder), most patients showed their total calcium intake between EAR and UL. Fifty percent of the patients were observed with dietary iron intake less than EAR, however most patients revealed their total iron intake with supplementation above UL. The addition of folic acid with supplementation increased mean total folic intake to $1126.0\;{\pm}\;152.4\;{\mu}g$ and ninety eight percent of the subjects showed their total folic acid intake above UL. The prevalence of anemia was 83.1 % assessed with hemoglobin level, even with high intakes of iron with supplementation. Thirty four percent of the patients showed their fasting blood glucose was not under control $(\geq\;126\;mg/dl)$ even with medication or insulin probably due to dextrose from dialysate. The mean blood lipid levels were within the reference levels of hyperlipidemia, but with 72.1 % of the patients showing lower HDL-C. In conclusion, Fairly large proportion of the patients were observed with protein malnutrition with low intake of protein and serum albumin level. Few patients showed their vitamins and minerals intake less than EAR with supplementation. For iron and folic acid, their intakes were increased to above UL for large proportion of he patients. However, more than eighty percent of the patients were still anemic associated with decreased renal function. The serum blood glucose and lipid level were not under control for some patients with medication. It seems that supplementation and medications that patients are taking should be considered for dietary consulting of CAPD patients.

• Korean Journal of Crystallography
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• v.14 no.1
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• pp.1-6
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• 2003

NiZn-ferrites were synthesized from the waste catalysts. which were by product of styrene monomer process and buried underground as an industrial wastes, and their magnetic properties were investigated. Nickel oxide and zinc oxide powders were mixed with finely ground waste catalysts, and spinel type ferrite was obtained by calcination at 900℃ and sintering at 1325℃ for 5 hours. The initial permeabilities were measured and reflection losses were calculated from S-parameters for the composition of Ni/sub x/Zn/sub 1-x/Fe₂O₄(x=0.36, 0.50, 0.66) and (Ni/sub 0.5/Zn/sub 0.5)/sub 1-y/Fe/sub 2+y/O₄(y=-0.02, 0, 0.02).

• Corrosion Science and Technology
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• v.15 no.5
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• pp.217-225
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• 2016

Linear polarization resistance (LPR) testing of soils has been used extensively by a number of water utilities across Australia for many years now to determine the condition of buried ferrous water mains. The LPR test itself is a relatively simple, inexpensive test that serves as a substitute for actual exhumation and physical inspection of buried water mains to determine corrosion losses. LPR testing results (and the corresponding pit depth estimates) in combination with proprietary pipe failure algorithms can provideauseful predictive tool in determiningthe current and future conditions of an asset. Anumber of LPR tests have been developed on soil by various researchers over the years1), but few have gained widespread commercial use, partly due to the difficulty in replicating the results. This author developed an electrochemical cell that was suitable for LPR soil testing and utilized this cell to test a series of soil samples obtained through an extensive program of field exhumations. The objective of this testing was to examine the relationship between short-term electrochemical testing and long-term in-situ corrosion of buried water mains, utilizing an LPR test that could be robustly replicated. Forty-one soil samples and related corrosion data were obtained from ad hoc condition assessments of buried water mains located throughout the Hunter region of New South Wales, Australia. Each sample was subjected to the electrochemical test developed by the author, and the resulting polarization data were compared with long-term pitting data obtained from each water main. The results of this testing program enabled the author to undertake a comprehensive review of the LPR technique as it is applied to soils and to examine whether correlations can be made between LPR testing results and long-term field corrosion.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.279-287
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• 2010

Interior permanent magnet synchronous motor(IPMSM) adjustable speed drives offer significant advantages over induction motor drives in a wide variety of industrial applications such as high power density, high efficiency, improved dynamic performance and reliability. This paper proposes efficiency optimization control of IPMSM drive using adaptive fuzzy learning controller(AFLC). In order to optimize the efficiency the loss minimization algorithm is developed based on motor model and operating condition. The d-axis armature current is utilized to minimize the losses of the IPMSM in a closed loop vector control environment. The design of the current based on adaptive fuzzy control using model reference and the estimation of the speed based on neural network using ANN controller. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM. The optimal current can be decided according to the operating speed and the load conditions. This paper considers the design and implementation of novel technique of high performance speed control for IPMSM using AFLC. Also, this paper proposes speed control of IPMSM using AFLC1, current control of AFLC2 and AFLC3, and estimation of speed using ANN controller. The proposed control algorithm is applied to IPMSM drive system controlled AFLC, the operating characteristics controlled by efficiency optimization control are examined in detail.

• Korean Journal of Community Nutrition
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• v.11 no.6
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• pp.785-792
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• 2006

The purpose of this study was to investigate the nutritional status before and after gastrectomy of gastric cancer patients in Jeonbuk Province. The subjects were 136 patients with gastrectomy of gastric cancer. We assessed the nutritional status before and after an operation by general characteristics (age, clinicopathological stage, type of operation, method of reconstruction), anthropometric characteristics (height, weight, skeletal muscle mass, body fat mass, body mass index (BMI), percent body fat, arm muscle circumference AMC, arm circumference AC) and biochemical characteristics (hemoglobin Hb, hematocrit Hct, mein corpuscular volume MCV, mean corpuscular hemoglobin MCH, total lymphocyte count TLC, serum albumin, serum transferrin). Mean ages were 60.0 yrs in males and 58.8 yrs in females. Age, clinicopathological stage, types of operation and reconstruction methods were not significantly different between males and females. Weight, skeletal muscle mass, body fat mass, BMI, percent body fat, AMC and AC significantly deteriorated by gastrectomy. There were severe weight losses in males and females after gastrectomy. Hemoglobin, Hct, MCV, MCH, TLC, albumin and transferrin significantly deteriorated by gastrectomy. After gastrectomy, subjects who were assessed as malnounrished in Hb and Hct were increased in male and those who were assessed as malnounrished in Hb were increased in females. These results suggest that a nutrition intervention, specially for energy, protein and iron, is necessary to improve the nutritional status of gastric cancer patients with gastrectomy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.47-54
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• 2008

Cost reduction requires lowering number of power devices used in the converter driving SRM. This is quite feasible in SRM drive systems than in other drive systems. This paper deals with analysis and simulation of a novel two phase SRM. A novel two phase SRM has high performance, self-starling capability, high efficiency, and low manufacturing cost. Additionally, the stator back iron does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited leading to a greater reduction in core losses. The magnetic analysis and design considerations of the novel two phase SRM have been obtained by the finite element analysis (FEM).