• Journal of the Korean Ceramic Society
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• v.15 no.4
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• pp.185-192
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• 1978

The effects of slag prticle size, $Na_2SO_4$ addition and sulphide in slag to the foam formation was investigated. This investigation showed that the slag particle size and the amount of $Na_2O$ had produced effects on the size of the foam, foam distribution and firing temperatures. In addition to that the amount of sulphide loss during the firing was controlling factor for the foam formation. The smaller slag particles and higher firing temperatures increased the loss of sulphide in the slag. The addition of $Na_2SO_4$ in the slag batch was likely to inhibit the foam formation. The larger slag particles resutled in the larger foam size and tended to be increasing the batch firing temperature. The main constituents of slag formed glass consisted of wallstonite and glassy phase. It is believed that the controlling the slag particle size and the amount of $Na_2SO_4$ in the slag batch will probably be main factors in foam formation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.536-543
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• 2009

In this paper the mean stress effects on the probability distribution of the random grown crack size at a specified loading cycle are studied through the fatigue crack propagation tests, which are conducted on the specimens of magnesium alloy under four different stress ratios. Through 80 replicates the probability distributions of the grown crack size are obtained. The goodness-of-fit for probability distributions of the random grown crack size are investigated by Anderson-Darling test and the best fit for those probability distributions is found to be a 3-parameter Weibull distribution. The effects of the mean stress on the probability distribution of the random grown crack size are also estimated.

• Journal of the Korean Ceramic Society
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• v.29 no.7
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• pp.572-576
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• 1992

Dielectric constant of ferroelectric ceramics with poling is important in relation to the mechanism of dielectric breakdown. From the research about the dielectric constant variation with poling in tetragonal and rhombohedral phase PZT ceramics, it is known that the dielectric constant after poling is determined by competing effects between increasing effects (compressive stress induced by electrostriction of piezoelectric effects) and decreasing increase in large grain size with poling is smaller than in small grain size.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.145-157
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• 1999

Wood dust is created when machines are used to cut or shape wood materials. Industries of high risk of wood dust exposure are sawmills, dimension mills, furniture industries, and carpenters, etc. Health effects associated with wood dust exposure includes dermatitis, allergic respiratory effects and cancer. Health effects of wood dus t are mainly depend on the concentration, dust size and exposure time. This study were carried out to evaluate the concentration and particle size distribution of wood dust during working processes. The subjects of this study were 53 workers exposed to wood dust in 7 furniture factories and 5 musical instruments, and 5 sawmill factories. The average total wood dust concentrations measured by personal cascade impactor were $1.82{\pm}2.31mg/m^3$ in primary manufacture, $3.59{\pm}1.72mg/m^3$ in s econdary manufacture, $5.09{\pm}1.46mg/m^3$ in sanding operation. Mass median diameters of hardwoods dust were $3.36{\mu}m$ in primary manufacture, $4.25{\mu}m$ in secondary manufacture, $4.21{\mu}m$ in sanding operation. softwoods dust were $3.39{\mu}m$ in primary manufacture, $4.34{\mu}m$ in secondary manufacture. Particle size distributions showed a nearly the same pattern in each working processes. The sample concentration of all hardwood dust exceeded the Threshold Limit Value(TLV) and 20.8% of the softwood dust exceeded the Threshold Limit Value. The range of size distribution were $0.5-10{\mu}m$ in the soft and hardwood dust. The respirable dust of soft and hardwood took up 59% and above. Therefore new threshold limit value for wood dust should be needed in Korea. Also, it should be done for various studies on health effects related to occupational exposure of wood dust.

• Fashion & Textile Research Journal
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• v.19 no.6
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• pp.795-803
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• 2017

This research aimed to figure out the effects of physical features such as BMI, garment size and socio-psychological factors such as self-esteem and depression on the body management. A survey was conducted for women in their 40's and 50's. The participants in this study consisted of 197 women recruited in Daegu and the surrounding areas. Statistical analysis including factor analysis, ANOVA, cluster analysis and regression was done using SPSS 23.0 to analyze the results. Among 3 clusters divided by BMI, normal group showed higher body cathexis compared with overweight group and obesity group. S-size group showed higher body cathexis rather than M, L-size groups. L-size group showed higher scores in nonsurgical body management factor. Self-esteem(+)/depression(-) group showed highest body cathexis among 4 groups clustered by self-esteem and depression levels. On the other hand, self-esteem(-)/depression(+) group showed the lowest body cathexis and highest surgical body management and nonsurgical body management factors. This result meant that the lower in self-esteem and the higher in depression, body cathexis decreased and desire for body management increased. As the results of analysis of the effects of BMI, garment size, self-esteem, depression level on body management, depression was a significant factor on surgical body management; depression and garment size were critical factors on nonsurgical body management.

• Animal Bioscience
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• v.34 no.6
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• pp.1061-1069
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• 2021

Objective: This study was conducted to evaluate the effects of feed processing and particle size on growth performance, nutrient digestibility, carcass characteristics, and gastric health in growing-finishing pigs. Methods: A total of 360 growing pigs (22.64±0.014 kg initial body weight [BW]) were allocated to 1 of 6 treatments with 6 replicates by BW and sex, and 10 pigs were housed in one pen in a randomized complete block design. The BW and feed intake were recorded to calculate growth performance. For the digestibility trial, a total of 24 barrows with an initial BW of 33.65±0.372 kg were split into 6 treatments with a completely randomized design. Dietary treatments were designed by a 2×3 factorial arrangement of treatments based on two main factors, particle size (600, 750, 900 ㎛) and feed form (mash and pellet) of diet. Experimental diets were formulated to contain the requirements of the NRC (2012). Results: The BW and average daily gain were not changed by dietary treatments, and the feed intake of finishing pigs (wks 6 to 12) was increased when the pigs were fed a mash diet (p<0.05). For the overall period, the feed efficiency of pigs was improved with the pellet diet (p<0.01) and reduced particle size (p<0.05). The pellet diet had effects on increasing crude fat digestibility (p<0.01) relative to a mash diet, but there was no considerable change in dry matter and crude protein digestibilities by dietary treatments. In the evaluation of gastric health, a trend for an increased incidence of keratinization in the esophageal region was observed as particle size decreased (p = 0.07). Conclusion: Feed efficiency could be improved by pellet diet and reduced particle size. Nutrient digestibility, carcass characteristics, and gastric health were not affected by feed form, and particle size ranged from 600 to 900 ㎛.

• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.51-56
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• 2005

Human perceptional speed is different from its real speed. There is lack of research that the perceptional speed is different from real speed in 2-dimension, because most research of speed perception has concentrated on points and lines. This research investigates the effects of object size on speed perception. In this research, we used 2-D circular objects of the different size, 0.9, 1.8 and $3.6^{\circ}$. The objects moved 9.0, 13.5 and $18.0^{\circ}$ with three different speeds, 6.0, 9.0 and $18.0^{\circ}$/s. Six participants were exposed to the environment with standard scene(size: $1.8^{\circ}$, speed: $9.0^{\circ}$/s and travel distance: $13.5^{\circ}$). After the first scene, another scene in which the object had changed to different sizes, speeds and distances, was shown to the participants. A magnitude estimation method was used to construct a scale of the perceived speed level. The relationship between the perceived and the actual speed level was explained by Stevens's power law that the value was 0.978 with the exponent of 0.992. The size of object had an effect on the speed perception but travel distance was not. The perceptional speed of bigger object was lower than of smaller object. It showed that the degrees of perceptional speed decreased as size of object increased.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.860-867
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• 2011

This study was performed to investigate the effects of the driving force for reduction and the surfactant (polyacrylic acid) on the size of Ag particles. As the driving force for reduction increases, the size of particles decreases due to a decrease of initial nuclei-size. Also, an increase of pH increases the amount of ionized surfactant, which leads to a decrease of particle size due to the prevention of particle growth. Both the driving force and the surfactant may affect the particle size, but the surfactant appeared to be a more dominant factor than reduction potential in terms of controlling the particle size. An increase of surfactant in the range of pH=3-4 decreases the size of Ag particles, although the reduction potential also decreases.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.1-6
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• 2002

Eggs obtained from 46 and 42 weeks old meat (Hybro) and layer (Leghorn) breeders flocks, respectively were used to examine the effects of genetic type of birds and egg size (small, medium and large) on variables of eggshell characteristics and hatchability traits. The variables measured were egg weight (EW), egg surface area (ESA) and eggshell characteristics (shell conductance (EC), per cent shell (PS), shell thickness (ST), shell volume (SV), shell density (SD) and hatchability traits (per cent hatchability (HP), early dead embryos (ED), late dead embryos (LD), pips with live embryos (PL) and pips with dead embryos (PD)). Genetic type of bird influenced all egg characteristics and HP of eggs. Eggs produced by the small Leghorn bird had lower EW, ESA, EC, ST, SV and HP than those produced by the heavy Hybro bird. The reduction of HP was associated with an increase in the percentage of ED and PL. Egg size influenced all variables measured except ST. Small size eggs had lower EW, ESA and EC and higher PS and SD than those of large eggs. Medium size eggs produced a higher HP when compared with that of large size eggs. The reduction of HP in large eggs was associated with higher percentage of ED, LD and PL. There were significant interactions between the genetic group of birds and egg size on LD and HP. Large egg size of Hybro birds had higher LD and lower HP than those of small size eggs produced by the same flock. However, There was no difference in HP and LD among the different egg sizes produced by Leghorn birds. It was concluded that genetic make up of birds and egg size influence eggshell characteristics and HP. The type of bird (heavy or small) influences the optimum egg size for successful hatching. Attention should be given to the size and eggshell characteristics of eggs of breeders' flocks for achieving maximum HP.

• The Journal of Korean Medicine
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• v.24 no.1
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• pp.133-140
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• 2003

Objectives : Kochiae Fructus (dried fruits of Kochia scoparia L. Schrad,) is used in the treatment of skin diseases as internal or external medicine in Oriental Medicine, but there has not been experimental study of Kochiae Fructus as an external medicine. The purpose of this study was to investigate if it has certain effects on the skin or not. Methods : By a skin prick test method, we evaluated the effects of wet dressing with Kochiae Fructus decoction in different concentrations on histamine-induced itch, erythema and wheal responses, and compared them with the effects of calamine lotion and distilled water in 8 healthy volunteers aged 26-32. Results : The mean intensity and duration of itch were most decreased after wet dressing with a Kochiae Fructus decoction of 100mg/150ml. The time required for erythema to reach the maximal size was around 5 minutes in all groups, and the size of erythema was smallest on the skin taking wet dressing with the Kochiae Fructus decoction of highest concentration. The size of wheal was also smallest after wet dressing with the highest concentration Kochiae Fructus decoction. The effects of wet dressing with Kochiae Fructus decoction on skin were dependent on their concentrations. Conclusions : Kochiae Fructus suppressed the histamine-induced skin responses, which supports the ancient herbal literatures which describe that Kochiae Fructus has a certain effectiveness on some skin diseases.