• Computers and Concrete
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• v.19 no.1
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• pp.33-39
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• 2017

In this study, two types of aggregate were used for making self-compacting concrete. Standard cubic specimens were exposed to different temperatures. Seventy-two standard cylindrical specimens ($150{\times}300mm$) and Seventy-two cubic specimens (150 mm) were tested. Compressive strengths of the manufactured specimens at $23^{\circ}C$ were about 33 MPa to 40 MPa. The variable parameters among the self-compacting concrete specimens were of sand stone type. The specimens were exposed to 23, 100, 200, 400, 600, and $800^{\circ}C$ and their mechanical specifications were controlled. The heated specimens were subjected to the unconfined compression test with a quasi-static loading rate. The corresponding stress-strain curves and modulus of elasticity were compared. The results showed that, at higher temperatures, Scoria aggregate showed less sensitivity than ordinary aggregate. The concrete made with Scoria aggregate exhibited less strain. The heated self-compacting concrete had similar slopes before and after the peak. In fact, increasing heat produced gradual symmetrical stress-strain diagram span.

• Parasites, Hosts and Diseases
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• v.52 no.1
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• pp.75-78
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• 2014

Sparganosis, an infection due to the plerocercoid of Spirometra erinacei, are found worldwide but the majority of cases occur in East Asia including Korea. This report is on a recurred case of sparganosis in the subcutaneous tissue of the right lower leg 1 year after a surgical removal of a worm from a similar region. At admission, ultrasonography (USG) of the lesion strongly suggested sparganosis, and a worm was successfully removed which turned out to be a sparganum with scolex. Since sparganum has a variable life span, and may develop into a life-threatening severe case, a patient once diagnosed as sparganosis should be properly followed-up for a certain period of time. Although imaging modalities were useful for the diagnosis of sparganosis as seen in this case, serological test such as ELISA should also be accompanied so as to support the preoperative diagnosis.

• Research in Mathematical Education
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• v.13 no.3
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• pp.181-195
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• 2009

Students' approaches to mathematical problem solving vary greatly with each other. The main objective of the current study was to compare students' performance with different thinking styles (divergent vs. convergent) and working memory capacity upon mathematical problem solving. A sample of 150 high school girls, ages 15 to 16, was studied based on Hudson's test and Digit Span Backwards test as well as a math exam. The results indicated that the effect of thinking styles and working memory on students' performance in problem solving was significant. Moreover, students with divergent thinking style and high working memory capacity showed higher performance than ones with convergent thinking style. The implications of these results on math teaching and problem solving emphasizes that cognitive predictor variable (Convergent/Divergent) and working memory, in particular could be challenging and a rather distinctive factor for students.

• Structural Engineering and Mechanics
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• v.16 no.4
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• pp.469-478
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• 2003

The primary aim of this study was to investigate the bond strength between reinforcement and concrete. Large sized nine beams, which were produced from concrete with approximately ${f_c}^{\prime}=30$ MPa, were tested. Each beam was designed to include two bars in tension, spliced at the center of the span. The splice length was selected so that bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. In all experiments, the variable used was the reinforcing bar diameter. In the experiments, beam specimens were loaded in positive bending with the splice in a constant moment region. In consequence, as the bar diameter increased, bond strength and ductility reduced but, however, the stiffnesses of the beams (resistance to deflection) increased. Morever, a empirical equation was obtained to calculate the bond strength of reinforcement and this equation was compared with Orangun et al. (1977) and Esfahani and Rangan (1998). There was a good agreement between the values computed from the predictive equation and those computed from equations of Orangun et al. (1977) and Esfahani and Rangan (1998).

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.27-34
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• 1999

This study presents the concept and the effects of the lifting two supports method that makes get economical design sections and efficient stress condition. The analysis of relation between critical sections and ratios Is done. Also, connection between critical sections and design variable is analyzed. In order to resolve the effects of the lifting two supports method, sections which was designed with the existing method, lifting support method, are used. Finally, it is proved that the new method is more efficient than the existing methods in economy and structure.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.16
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• pp.75-80
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• 1987

This paper is deals with the preventive replacement for the equipment which fails only when the total amount of damage reaches a prespecified failure level. Most of replacement model use time as their decision variable, but it is not appropriate for the cases in which failures dependent on their cumulative damage levels. In this paper, a new type preventive replacement model is introduced in which an equipment is replaced before failure when the cumulative damage reaches a certain level or replaced on failure, whichever occures first. The optimal replacement damage levels which minimize total expected cost are obtained by the Dynamic programming Method when the number of use of the equipment is finite. A numerical example is also presented. The optimal preventive replacement policy when the equipment will be used for a finite time span is also discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3878-3884
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• 1975

This study was carried out to develop the throw-in type thresher with its size as small as possible. Developing the smallest possible size of the throw-in type thresher has been very important to increase mobility and to reduce the machine price. The thresher that developed for this purpose was tested as to threshing and separation performance for the samples collected in eight catch boxes under the concave while threshing. The amount of grain collected in each compartments was measured and the threshing and separating pattern along the total span of the threshing drum was determined. The performance of separating and threshing units of the test thresher and threshing loss was evaluated by use of the developed grain separating apparatus and the method for measuring the grain separating performance of threshers. The results are summarized as follows; 1. The unthreshed grain (drum losses) and semi-threshed grain did not appeared at all throughout the treatments. 2. When threshed by making use of the developed throw-in type thresher, the threshing grain loss at about 25 per cent grain moisture was about one-half when threshed at about 18 per cent grain moisture. 3. And its grain separating loss in higher feed rate was decreased in comparison with that of lower feed rate. These results suggests that the throw-in type thresher may be suitable for wet threshing and for higher feed rate of threshing. 4. Above 60 per cent of total grain passing through concave fell through the screen within a scant 30 cm from the feeding inlet. This threshing pattern may suggest that major threshing action may be finished before about one third of cylinder length. The required separating load extended over the whole drum span is so defferent that separating elements should be redesigned so as to accomodate this variable pattern of separation load. 5. It was apparent from the experiment that the length of the threshing drum of the throw-in type thresher could be reduced from 1285mm to about 1050mm without increasing grain separation loss greatly.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.63-71
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• 1989

Four series of reinforced concrete beams were tested to determine their shear cracking strengths and ultimate shear capacities. All beams were singly reinforced without shear reinforcement. The concrete strength was the prime variable which was varied from 247 to $708kg/cm^2$(8500 to 10000 psi). Within each series the shear span-to-depth ratio was varied from 2 to 5, while concrete strength was held constant. Test results indicate that the effect of concrete strength on shear capacities is varied as the shear span-to-depth ratio is changed. Furthermore, the current shear design provisions do not provide a consistency with respect to estimating shear capacities of reinforced concrete beams. By introducing the shear failure mode index, a new equation is proposed to predict ultimate shear strengths of reinforced concrete beams without web reinforcement.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.271-280
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• 2007

This paper presents the results of an experimental study to evaluate the redundancy in two plate-girder bridges, which are generally classified as non-redundant load path structures. The study was performed at a time when one of the two girders was damaged. The bottom lateral bracing was considered the experimental variable, and two 1/5-scale bridge specimens of simple span with and without a lateral bracing system were fabricated. Loading tests were first performed on the intact specimens without a cracked girder, within an elastic range. Thereafter, the ultimate loading tests were conducted on the damaged specimens with an induced crack at the center of a girder. The test results showed that the cross beams and the concrete deck redistributed some of the load to the uncracked girder, but the lateral bracing system played an important role in improving the redundancy during the damage and was also effective for load redistribution even when the bridge was intact.

• Herbal Formula Science
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• v.10 no.2
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• pp.113-126
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• 2002

Soamsan is known as an anti-cancer remedy in the traditional Korean Medicine. To enhance the synergic effects of anti-cancer activity of Soamsan, this study reconstituted the original components of Soamsan with a slight modification and produced a novel herbal remedy, namely Gamisoamsan. Extracts of Gamisoamsan inhibited the growth of cultured CT-26 cells, mouse colon adenocarcinoma, in a dose-dependent manner $(1\;to\;50{\mu}g/ml)$, and $ID_{50}$ was estimated approximately $16.7{\mu}g/ml$. Using tumor-bearing mouse model, in which was produced by subcutaneous injection of CT-26 cells ($1{\times}10^5$cells). the effects of Gamisoamsan on tumor growth and host survival were examined by evaluating tumor volume and increase in life span. When Gamisoamsan extracts in variable doses of 100, 200 and 500mg／kg body weight per day were orally administered to tumor-bearing mice, following results were obtained: Improvement in the hematological parameters following Gamisoamsan treatment such as hemoglobin contents, red blood cells and white blood cells of the tumor-bearing mice have been observed. Gamisoamsan treatment also showed a prolongation of life span and a reduction of tumor volume in the CT-26 tumor hosts. The results of the present study suggest that Gamisoamsan extracts has a potential anti-tumor activity and may be an useful remedy to prevent and／or treat cancer.