• The Journal of the Korean dental association
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• v.48 no.4
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• pp.263-274
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• 2010

I classified the bone graft material according to the component. Most bone graft material is composed of inorganic and organic constituent. Organic component such DBM is associated with osteoinduction. Inorganic components such as hydroxyapatite, $\beta$-TCP, calcium sulfate, bioactive glass, polymer are associated with osteoconduction. Autogenous bone graft is ideal material. We can select any biocompatible material for the restoration of small filling defect with intact bony wall. However, we should select first osteogenetic and osteoinductive material to regenerate the viable bone tissue.

• Geotechnical Engineering
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• v.13 no.3
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• pp.21-32
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• 1997

In this paper, an enhanced finite element model based on homogenisation technique is proposed to capture the localized failure mode of the intact rock masses. For this, bifurcation analysis at the element level is performed and, once the bifurcation is detected, equivalent material properties of the shear band and neighbouring intact rock are used to trace the post -peak behaviour of the material. It is demonstrated that mesh sensitivity of the strain softening model is overcome and progressive failure mode of rock specimen can be simulated relaistically. Furthermore, the numerical results show that the crack propagation and final failure mode can be captured with relatively coarse meshes and compares well with the experimental data available.

• International Journal of Highway Engineering
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• v.19 no.1
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• pp.73-80
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• 2017

PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over fine-grained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade model-based comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.643-648
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• 2010

Waterjet is a very useful technology for rock excavation because of low level noise and vibration during breaking rocks. To accurately predict the volume and shape excavated by the waterjet, it is important to understand waterjet fracture mechanisms. There have been various theoretical assumptions and approaches in the literature. In this study, waterjet mechanisms are classified into three standards: a mechanism scale, theoretical assumption for a target material, and jet phase. In addition, through a waterjet experimental study for weathered and intact granitic rocks, a fracture shape is observed and analyzed on comparison with the previous mechanisms. As a result, best waterjet mechanisms are selected to explain the fracture pattern of the granitic rocks.

• Geomechanics and Engineering
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• v.3 no.1
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• pp.61-81
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• 2011

In this paper, a complement to the Hoek-Brown criterion is proposed in order to derive the strength of anisotropic rock from strength of the corresponding truly intact rock. The complement is a decay function, which unlike other modifications or suggestions made in the past, is multiplied to the function of the original Hoek-Brown failure criterion for intact rock. This results in a combined and extended form of the criterion which describes the strength of anisotropic rock as a varying fraction of the corresponding truly intact rock strength. Statistical procedures and in particular regression analyses were conducted into data obtained in experiments conducted in the current research program and those collected from the literature in order to define the Hoek-Brown's criterion complement. The complement function was best described by a simple polynomial including only three constants to be empirically evaluated. Further investigations also showed that these constants can be related to the other readily available parameters of rock material which further facilitate determining the constants. A great and prime advantage of the proposed complement is that it is mathematically simple including the least possible number of empirical constants which are easily estimated with minimum experimental effort. Moreover, proposed concept does not suggests any change to the original Hoek-Brown criterion itself or its constants and serves whenever anisotropy does exist in the rock. This further implies on the possibility of using any other failure criterion for intact rock in conjunction with the compliment to reach the strength of anisotropic rock.

• Geomechanics and Engineering
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• v.17 no.6
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• pp.597-606
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• 2019

Ultrasonic Time-of-Flight Diffraction (TOFD) techniques are useful methods for non-destructive evaluation of fracture characteristics. This study focuses on the reliability and accuracy of ultrasonic diffraction methods to estimate the depth of rock fractures. The study material includes three different rock types; andesite, basalt and ignimbrite. Four different ultrasonic techniques were performed on these intact rocks. Artificial near-surface fracture depths were created in the laboratory by sawing. The reliability and accuracy of each technique was assessed by comparison of the repeated measurements at different path lengths along the rock surface. The standard error associated with the predictive equations is very small and their reliability and accuracy seem to be high enough to be utilized in estimating the depth of rock fractures. The performances of these techniques were re-evaluated after filling the artificial fractures with another material to simulate natural infills.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.581-584
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• 2008

At the inlet and outlet differential pressure and The fluid velocity over 32m/s are damaged (Plug, sheet ring, trim) About reduction trim parts of the control valve. AOV of the differential pressure 1,500psi become often the damage in the nuclear power plant. Damages of AOV studied CFD analysis and improvement program. Multi-stage trim designs which decrease a fluid kinetic energy are demanded and AOV parts are demanded case hardening and material change.

• Geotechnical Engineering
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• v.14 no.3
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• pp.47-62
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• 1998

The disturbed state concept (DSC) proposed here is based on the idea that a deforming material element can be treated as a mixture of two constituent parts in the relative intact (Rl) and fully adjusted (FA) states, referred to as reference states. Based on this idea, DSC provides a unified constitutive model for the characteristics of saturated sands under cyclic loading. The model parameters for saturated sands are evaluated by using data from truly triaxial test device, The laboratory test results are also used for the verification of D SC model. In general, the model predictions are found to provide satisfactory correlation with the test results. From the results of this research, it can be stated that the DSC model is capable of characterizing the cyclic behavior of saturated sands under dynamic loading.

• Journal of Crop Science and Biotechnology
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• v.10 no.1
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• pp.13-18
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• 2007

Near-infrared spectroscopy(NIRS) was used as a rapid and nondestructive method to determine the fatty acid composition in intact seed samples of rapeseed(Brassica napus L.). A total of 349 samples(about 2 g of intact seeds) were scanned in the reflectance mode of a scanning monochromator, and the reference values for fatty acid composition were measured by gas-liquid chromatography. Calibration equations for individual fatty acids were developed using the regression method of modified partial least-squares with internal cross validation(n=249). The equations had low SECV(standard errors of cross-validation), and high $R^2$(coefficient of determination in calibration) values(>0.8) except for palmitic and eicosenoic acid. Prediction of an external validation set(n=100) showed significant correlation between reference values and NIRS estimated values based on the SEP(standard error of prediction), $r^2$(coefficient of determination in prediction), and the ratio of standard deviation(SD) of reference data to SEP. The models developed in this study had relatively higher values(> 3.0 and 0.9, respectively) of SD/SEP(C) and $r^2$ for oleic, linoleic, and erucic acid, characterizing those equations as having good quantitative information. The results indicated that NIRS could be used to rapidly determine the fatty acid composition in rapeseed seeds in the breeding programs for high quality rapeseed oil.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.191-195
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• 2007

This study reveals the unusual case reported for the first time on the selective non digestion of yellow mealworm (Tenebrio molitor) larvae by arowana fish. In January 2005, an Asian arowana (Scleropages formosus) (red variety), from Daesang Tropical Fish Corporation, Seoul, Korea, mortality was observed due to unknown cause. No putative causal factors were suggested by bacteriological and parasitological examinations. Internal examination of the dissected stomach showed some undigested debris with mandible parts of mealworms attached to the mucosal lining of stomach wall. Feeding experiment of yellow mealworm (Tenebrio molitor) was conducted on the silver arowana (Osteoglossum bicirrhosum). Result showed that on the test group, fish released vomitous material containing undigested mandibles of mealworm was observed on the 24th day of the feeding experiment. Histopathological examination of the cross section of the stomach wall layers of the test groups, showed detached parts of the mucosal layer and gastric pits around the damaged area with intact mucularis tissues. While the control group fed with mealworm larvae without head part showed intact stomach wall layers consisting of gastric pit, mucosa and mucularis tissues. Fish on both treatments survived until the termination of experiment. The removal of mealworm larvae head before feeding probably help or aid in the fast digestion of these insect larvae.