• Journal of the Korean Society for Precision Engineering
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• v.21 no.12
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• pp.154-159
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• 2004

This study is aimed to diminish the errors which created during transforming from 3D shape created with CAD program to STL file formation. The length strain which created on X-Y axises at STL file transforming is diminished by using the relation between common shape error and shrinkage rate. As the result of study, we have confirmed the length strain in accordance with facetres value. Also, the shape error is compensated with shrinkage rate by error of length strain. so, we could diminish to shape error by several tens micrometer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.223-226
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• 2004

It is net easy to predict the shrinkage rate of a plastic injection mold in its design process. The shrinkage rate should be considered as one of the important performances to produce the reliable products. The shrinkage rate can be determined by suing the CAE tools in the design produces. However, since the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models based on the RSM is used in lien of the original models, facilitating design optimization.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.57-63
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• 2013

PURPOSES : This study was performed to investigate a feasibility of job-site use of recycled concrete aggregate exceeding 3% of absorption rate. Test variables are coarse aggregate types such as natural aggregate, job-site processed recycled aggregate, and recycled aggregate processed from the intermediate waste treatment company. METHODS : First, aggregate properties such as gradation, specific gravity and absorption rate were determined. Next a basic series of mechanical properties of concrete was tested. RESULTS : All strength test results such as compression, flexure and modulus were satisfied for the minimum requirements. Finally up to first 48 elapsed days the shrinkage strains of concretes made from both recycled aggregates (in case of volume-surface ratio of 300) appeared to be greater than 26% of the companion concretes made from natural aggregates. CONCLUSIONS : Drying shrinkage result is ascribed to greater absorption rate and specific gravity of those specimens made from recycled aggregate. This may be reduced with an addition of admixtures.

• Journal of Ginseng Research
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• v.18 no.1
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• pp.60-65
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• 1994

Fresh ginseng of same grade was stored under the 4$\pm$1$^{\circ}C$ and 87~92% RH for 10 weeks. During the storage, an aliquot amount of the ginseng was drawn, freeze dried and chemical constituents and physicochemical parameters were measured. After 10 weeks of storage drying rate and shrinkage of ginseng were 1520% and 9.04%, respectively, mold growth was seen at week 5 and observed for 51.2% of the ginseng week 10. Amylase activity level was elevated at the early stage of storage and decreased to 5% of initial value at week 5. At week 5, the elevated amylase activity was inconcomitant with the appearance of the mold growth. Crude protein contents were increased and decreased, respectively 5 week post storage. No significant changes in crude fat, crude fiber, ash, total sugar, n-butanol extract and ginsenoside were observed. The content of water-extractable substance showed maximum at week 7 to 8. The value of pH was slightly elevated and reducing sugar was increased during the storage. Key words Ginseng storage, physicochemical properties, drying rate, shrinkage, amylase activity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.179-180
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• 2023

In this study, the performance of the prediction model was compared and analyzed using DNN and LSTM learning models to predict the amount of dry shrinkage of the concrete. As a result of the analysis, DNN model had a high error rate of about 51%, indicating overfitting to the training data. But, the LSTM learning model showed a relatively higher accuracy with an error rate of 12% compared to the DNN model. Also, the Pre_LSTM model which preprocess data, showed the performance with an error rate of 9% and a coefficient of determination of 0.887 in the LSTM learning model.

• Journal of the Korean Society of Clothing and Textiles
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• v.3 no.2
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• pp.15-22
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• 1979

The heat setting of sewing thread is known to have some puckering. In this experiment, the P/C fabrec and polyester thread were heat setted at temperatures ranging from $70^{\circ}C$ to $150^{\circ}C$ at the interval of every $^20{\circ}C$ for the period of 1, 5, 10, 20 and 40 minutes resoectivly. The results obtained are as follows: 1) In general, the pre-laundering sewing shrinkage related negatively to time but related positively to temperature. And it showed the lowest rate at $110^{\circ}C$. 2) In case of slack treatment, the post-laundering sewing sewing shrinkage marked the lowest rate at $130^{\circ}C$ while that of stretch treatment showed the lowest rate at $90^{\circ}C$. 3) The rates of post-laundering sewing shrinkage were higher than those of pre-laundering shrinkage, the difference between them reached the bottom when applied the slack treatment at $130^{\circ}C$ and the streched treatment at $110^{\circ}C$.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.726-733
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• 2002

Shrinkage strip or separation strip is a temporary joint that is left open for a certain time during construction to allow a significant part of the shrinkage to take place without inducing stress. A shrinkage stress analysis method of shrinkage strip in concrete slab of multi-story building considering the relaxation effect of creep and construction sequence is proposed. The analysis results of 10-story example building show that the effect of shrinkage strip can be analyzed easily by the proposed method. And shrinkage strip installed in a particular floor makes the stress of that floor reduced and the stress of the other floors increased a little. The rate and amount of stress reduced with closing time mainly depends on the development of shrinkage with time of concrete model used. The amount of stress reduced is determined by the amount of shrinkage strain developed before the closing of shrinkage strip.

• The Research Journal of the Costume Culture
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• v.16 no.3
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• pp.461-474
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• 2008

The purpose of this study was to present a making method of jeans pattern with high fitness after deriving the appropriate shrinkage rate by material and washing process. Research Method of jeans pattern was presented after applying the optimized shrinkage rate. According to the result of the exterior evaluation of test jeans, all 6 jeans were rated high with scores close to 3.5. Following the evaluation of satisfaction of usage by physical movement, the highest ranking was in the order of walking with normal steps, back bending $90^{\circ}$, chair sitting, climbing stairs, and squatting. The shrinkage rate by physical area showed the highest score in the order of pants length, waist circumference, thigh circumference, knee circumference, hem circumference, hips circumference. In addition, the shrinkage rate was higher in warp direction than weft direction after washing finishing. As for the result of addition and reduction of pattern measurements by parts of jeans, waist circumference was $2.5{\sim}5.2cm$, hips circumference was $-1.8{\sim}2.8cm$, thigh circumference was $-1.3{\sim}2.0cm$ and knee circumference was $-1.0{\sim}1.7cm$. Also, hem circumference was $-1.0{\sim}1.8cm$ and pants length was $2.9{\sim}6.2cm$. That is, this results showed a wide range of addition and reduction according to material and washing finishing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.180-181
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• 2017

This study aims to analyze the high strength mortar's fundamental properties and autogenous shrinkage properties by taking into consideration the result of the previous study in which it was found that ERBO(Biodiesel) exercises greatest effect on the expansion effect of mortar, and changing the time and rate of mixing the ERBO. A total of five levels were set as experimental variables: the three levels of the rate of ERBO, 0, 0.5, 1.0%, and the two levels of the time of mixing the ERBO: first, adding the ERBO with the mixing water and mixing it before, and second, mixing it after the mortar is completely mixed. It was found that the rate of length change decreased as the rate of ERBO increased, and the rate of length change was lower when the ERBO was mixed sooner.

• Journal of Technologic Dentistry
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• v.42 no.2
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• pp.113-120
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• 2020

Purpose: This study is to compare and analyze the shrinkage of the specimen after UV irradiation of UV cured resin at 5, 15, and 30 minutes. Methods: A cylindrical UV cured specimen was produced using a stainless steel mold. UV cured resin specimens were prepared in three groups: 5 minutes cured (5M), 15 minutes cured (15M), and 30 minutes cured (30M). The measurement was made in total 3rd. The measurement was made in total 3rd. The primary measurement was made after 24 hours using a digital measuring instrument. The 2nd and 3rd measurements were deposited in a constant temperature water bath and the shrinkage was measured. The measured data was calculated by referring to the ASTM C326 linear measurement calculation method. T-test and One-way ANOVA were performed to test the significance between groups. The post-test was conducted with Tukey (α=0.05). Results: When the inner diameter and the outer diameter of the three groups not placed in the water bath were compared and analyzed, the contraction was the smallest at 6.8% in the 5M group, and the contraction was the largest at 7.3% in the 30M group. In the outer diameter, the contraction of the 5M group was the smallest at 3.5%, and the contraction of the 30M group was the largest at 4.5%. Shrinkage decreased in all three groups immersed in a water bath for 3-7 days. Conclusion: In the UV cured resin specimen, the shrinkage increased as the amount of UV irradiation increased.