• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.4
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• pp.361-369
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• 2008

Control of ground water is one of the most important factors for long-term operation of tunnel because most of tunnel is located in the ground. In case of leakage tunnel, there is no pore water pressure on the lining when the drainage system is properly working. After long-term operation, however, the pore water pressure can be developed on the lining due to the deterioration of the drainage system. The increased pore water pressure on the lining is termed here as 'residual pore water pressure'. Residual pore water pressure can be measured by piezometer, but it is generally not allowed because of damages of drainage system. Therefore, an indirect and nondestructive method is required for evaluating the residual pore water pressure. Moreover, understanding of pore water pressure is needed during healthy operation of the lining. In this study, a new method for evaluation of pore water pressure on the lining during operation is proposed using theoretical and numerical analysis. It is shown that the method is particularly useful for stability investigation of pore water pressure on the lining during operation using theoretical analysis with normalized pore water pressure curve.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.29-36
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• 2001

This paper was made to evaluate the effect of the blending ration of GCC and No. 1 clay on the printability by investigating the structure of pore such as the pore rate, the number of pores, pore size and distribution of coated paper. The coated structure is mainly depended on the results of correlation between pigment and binder. It means that the structure of the pore occurred is chiefly affected by the blending ratio of GCC and No. 1 clay. This physical properties of the pore have a close relation with ink set-off associated with the drying rate and the penetration in ink into base paper and with printing gloss. Therefore it was needed to find out how the pore structure and the printability will be changed by modifying the blending ratio of GCC and No. 1 clay to vary the pore structure of coated paper. Below are the results of measurement: As the blending ratio of clay going up, water retention, sedimentation volume. smoothness, and paper gloss were increased, but relatively brightness and opacity were decreased. Pore rate was the highest at the blending ratio of No. 1 clay to GCC, 70:30. In this case, average pore radius was also increased. Ink receptivity and K&N ink receptivity were improved with the increase of the blending ratio of GCC, where was, ink setting was vice versa. No difference was observed in the weight of ink, but ink repellance decrease with the decrease of blending ratio of GCC.

• Textile Coloration and Finishing
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• v.11 no.6
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• pp.1-6
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• 1999

The porosities of PET fibers were investigated using a nitrogen porosimeter according to oxygen plasma treatment and dyeing with a disperse dye, and they were discussed in terms of the change of internal micro-structure of the PET fiber. The total pore volume, surface area and average pore size of the plasma treated PET fibers increased expectably compared with the untreated sample. The PET fibers treated with oxygen plasma and then dyed with a disperse dye were increased significantly in the surface area and the total pore volume comparing with those of plasma treated only, but decreased in the average pore size. The increase of the surface area, after dyeing, of the plasma treated PET fibers was due to addition of the surface area of the dye itself to that of the PET fiber. The increase of the total pore volume of the plasma treated PET fibers by dyeing, which is the opposite result to the general idea that the pore volume of fibers would be reduced by occupation of dye molecules in the pores, could be explained by the free-volume model. This is that the amorphous region in the fiber expanded by occupation of dye molecules, and the marginal space surrounding dyes was generated as many smaller pores, and the decrease of the average pore size of the dyed sample also could be explained The decrease of the average pore size was caused by the splitting of a larger pore into smaller pores.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.681-691
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• 2018

The typical methods of mercury intrusion porosimetry (MIP) and capillary flow porometry (CFP) were used to evaluate the pore size of cross-section of wood and the effect of the pore structure on the permeability of wood was analyzed in this study. The results of this study were as followings: The pore size of wood measured by CFP was larger than that measured by MIP except for Lime tree, Korean red pine and Paulownia. Among the three pore types of porous materials defined by IUPAC (through pores, blind pores, and closed pores), only through pores are related to permit fluid flow. MIP measures the pore size of both through pores and blind pores, while CFP measures the pore size of only constricted through pores. Therefore, pore size measured by MIP was not related to gas permeability, however pore size measured by CFP had a proportional relationship with gas permeability.

• Computers and Concrete
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• v.17 no.1
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• pp.107-127
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• 2016

Concrete is a heterogeneous material containing many weaknesses such as micro-cracks, pores and grain boundaries. The crack growth mechanism and failure behavior of concrete structures depend on the plastic deformation created by these weaknesses. In this article the non-linear finite element method is used to analyze the effect of presence of micro pore near a crack tip on both of the characteristics of crack tip plastic zone (its shape and size) and crack growth properties (such as crack growth length and crack initiation angle) under pure shear loading. The FE Code Franc2D/L is used to carry out these objectives. The effects of the crack-pore configurations and the spacing between micro pore and pre-excising crack tip on the characteristics of crack tip plastic zone and crack growth properties is highlighted. Based on the obtained results, the relative distance between the crack tip and the micro pore affects in very significant way the shape and the size of the crack tip plastic zone. Furthermore, crack growth length and crack initiation angle are mostly influenced by size and shape of plastic zone ahead of crack tip. Also the effects of pore decrease on the crack tip by variation of pore situation from linear to perpendicular configuration. The critical position for a micro pore is in front of the crack tip.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.277-282
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• 2004

In a hardened concrete, diffusion of oxygen, carbon dioxide, aggressive ions, and moisture from the environment to the concrete takes place through the pore network. It is well known that making dense cement matrix enhances the durability of concrete as well as all the characteristics including strength of concrete. In this paper,9 mix concretes with water to cementitious material ratio (40,45, and $50\%$) and replacement ratio of GGBFS (40 and $60\%$ of cement by weight) were studied on the micro-pore structure by mercury intrusion porosimetry and the accelerated chloride diffusion test by potential difference. From the results the average pore diameter and accelerated chloride diffusivity of concrete were ordered NPC > G4C > G6C. It is concluded that there is a good correlation between the average pore diameter and the chloride diffusivity, and the mineral admixtures has a filling effect, which increases the tortuosity of pore and makes large pores finer, on the pore structure of cement matrix due to the latent hydraulic reaction with hydrates of cement.

• Journal of the Semiconductor & Display Technology
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• v.19 no.1
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• pp.36-41
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• 2020

In this paper, We need to change all print factors when which print scaffold with 400 ㎛ pore using FDM 3d printer. Therefore the print quantity is 10 billion times, So we are difficult to print on workplace. To solve the problem, we used the prediction model based machine learning regression. We preprocessed and learned the securing print condition data, and we produced different kinds of prediction models. We predicted the pore size of scaffolds not securing with new print condition data using prediction models. We have derived the print conditions that satisfy the pore size of 400 ㎛ among the predicted print conditions of pore size. We printed the scaffolds 5 times on the condition. We measured the pore size of the printed scaffold and compared the average pore size with the predicted pore size. We confirmed that error was less than 1%, and we were identify the model with the highest pore size prediction performance of scaffold.

• YAKHAK HOEJI
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• v.29 no.4
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• pp.176-182
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• 1985

As a part of the studies on adsorptive properties of Korean halloysite clays, Hadong white clays of premium grade were examined for geometric pore structured by mercury porosimetry and for specific surface areas by nitrogen adsorption according to the BET procedure. Three size fractions of the native clay sample were derived from passage BS #100, #200 and #325 meshes, respectively. Several parameters lhus observed in relation to the pore structures are shown below: 1. The size fraction of BS #100, #200 and #325 show internal pore volumes of 25.3, 30.2 and $35.0m^2g^{-1}$, respectively. 2. In the distribution curves of the cumulative pore volume against pore diameter, it has been shown that the larticle sizes, the steeper the distribution over the larger ranges of pore diameters. The converse is true the smaller particles. 3. Internal pore areas increase with decrease in pore sizes. It follows that the pores having diameters of $\leq$0.1$\mu\textrm{m}$ are responsible for more than 90% of the total pore area. 4. The behaviour of nitrogen adsorption can be best described by BET type IV isotherm. Further, the hysteresis loops of the adsorptiondesorption curves become narrower with decresing particle sizes. 5. The specific surface areas observed for the fractions of BS #100, BS #200 and BS #325 are 34.6, 35.4 and 43.2m $^2g^{-1}$, respectively. and the calcined clay of BS #325 has a specific surface area near $30.4m^2g^{-1}$.

• Korean Journal of Metals and Materials
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• v.49 no.7
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• pp.530-534
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• 2011

To analyze the effect of the pore size of graphite in a pore-forming agent, graphite was added to porous ceramics of $Al_2O_3-SiO_2-ZrO_2$ systems. The graphite had 45~75, 100~125, 150~180, and 75~180${\mu}m$ dimensions. The properties of the ceramics, such as apparent porosity, density, dynamic elastic modulus, mechanical strength, and permeability, were investigated. The average pore size increased from 15.35${\mu}m$ to 22.32${\mu}m$ with the increase of the graphite size. The sample with the largest average pore size showed the highest mechanical strength and gas permeability. This was due to the sample with the largest pore size at the same porosity having fewer pores and larger distance between the pores than the sample with the smallest pore size, making cracks less likely to propagate. In addition, the large pore size reduced the repulsive power originating from the drag force between the gas and internal pore walls.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.135-144
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• 2015

Fingerprint pores have proven to be useful features for fingerprint recognition and several pore-based fingerprint recognition systems have been reported recently. In order to recognize fingerprints using pore information, it is very important to extract pores reliably and accurately. Existing pore extraction methods utilize 2D model fitting to detect pore centers. This paper proposes a pore extraction method using 1D Gaussian model which is much simpler than 2D model. During model fitting process, 1D model requires less computational cost than 2D model. The proposed method first calculates local ridge orientation; then, ridge mask is generated. Since pore center is brighter than its neighboring pixels, pore candidates are extracted using a $3{\times}3$ filter and a $5{\times}5$ filter successively. Pore centers are extracted by fitting 1D Gaussian model on the pore candidates. Extensive experiments show that the proposed pore extraction method can extract pores more effectively and accurately than other existing methods, and pore matching results show the proposed pore extraction method could be used in fingerprint recognition.