• 펄프종이기술
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• 제33권1호
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• pp.53-61
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• 2001

This study was carried out to evaluate the effect of coating pigments on the printability by investigating the pore structure of casting layer such as the number, size and distribution of pores and the pore rate. The coating structure was mainly determined by the interaction between pigment and binder. It means that the structure of pores was chiefly affected by the shape and size distribution of pigments and their packing rate. The physical properties of pore have close relationships with ink set-off, the speed of ink penetration and printing gloss. The results suggested that the rate and number of pores were greatly affected by the particle size distribution and shape of pigments. The rate of pore increased with the reduction of particle size distribution of pigments. Calcite was effective to improve greatly the printability of coated paper.

• Membrane and Water Treatment
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• 제13권6호
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• pp.313-320
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• 2022

Theoretical calculation results are presented for the enhancement of the water mass flow rate through the hydrophobic micro/nano pores in the membrane respectively on the micrometer and nanometer scales. The water-pore wall interfacial slippage is considered. When the pore diameter is critically low (less than 1.82nm), the water flow in the nanopore is non-continuum and described by the nanoscale flow equation; Otherwise, the water flow is essentially multiscale consisting of both the adsorbed boundary layer flow and the intermediate continuum water flow, and it is described by the multiscale flow equation. For no wall slippage, the calculated water flow rate through the pore is very close to the classical hydrodynamic theory calculation if the pore diameter (d) is larger than 1.0nm, however it is considerably smaller than the conventional calculation if d is less than 1.0nm because of the non-continuum effect of the water film. When the driving power loss on the pore is larger than the critical value, the wall slippage occurs, and it results in the different scales of the enhancement of the water flow rate through the pore which are strongly dependent on both the pore diameter and the driving power loss on the pore. Both the pressure drop and the critical power loss on the pore for starting the wall slippage are also strongly dependent on the pore diameter.

• 한국농공학회지
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• 제30권3호
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• pp.38-50
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• 1988

carried out to present a rheology model which is able to treat time-dependent properties of clay. The results were summarized as follow ; 1. The slope (a(e1)) of deviator stress in strain rate test was independent on axial strain, and pore water pressure was decreased with increment of strain rate. 2. The pore water pressure in a stress relaxation condition was not changed when the strain rate before stress relaxation was 0.05%/min., but it was increased with increment of time when the strain rate before stress relaxation was 0.2%/min 3. The greater the stress condition (q/qmax) and the strain rate before creep test became, the greater the increment rate of axial strain in creep test became. 4. SEKIGUCHI's constitutive equation was slightly overpredicted while empirical equation proposed in the study was well coincided with measured values. 5. The constitutive equation induced by a strain function could be dealed with a behavior of the pore water pressure increased with increment of elapsed time after primary consolidation.

• 지질공학
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• 제29권4호
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• pp.367-381
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• 2019

We investigate pore pressure conditions and reservoir compaction associated with oil and gas production using 3 different permeability models, which are all based on one-dimensional radial flow diffusion model, but differ in considering permeability evolution during production. Model 1 assumes the most simplistic constant and invariable permeability regardless of production; Model 2 considers permeability reduction associated with reservoir compaction only due to pore pressure drawdown during production; Model 3 also considers permeability reduction but due to the effects of both pore pressure drawdown and coupled pore pressure-stress process. We first derive a unified stress-permeability relation that can be used for various sandstones. We then apply this equation to calculate pore pressure and permeability changes in the reservoir due to fluid extraction using the three permeability models. All the three models yield pore pressure profiles in the form of pressure funnel with different amounts of drawdown. Model 1, assuming constant permeability, obviously predicts the least amount of drawdown with pore pressure condition highest among the three models investigated. Model 2 estimates the largest amount of drawdown and lowest pore pressure condition. Model 3 shows slightly higher pore pressure condition than Model 2 because stress-pore pressure coupling process reduces the effective stress increase due to pore pressure depletion. We compare field data of production rate with the results of the three models. While models 1 and 2 respectively overestimates and underestimates the production rate, Model 3 estimates the field data fairly well. Our result affirms that coupling process between stress and pore pressure occurs during production, and that it is important to incorporate the coupling process in the permeability modeling, especially for tight reservoir having low permeability.

• 펄프종이기술
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• 제33권3호
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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.

• 한국산림과학회지
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• 제85권1호
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• pp.66-75
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• 1996

본 연구는 산불 발생이 임지의 수저류 특성에 미치는 영향을 알아보기 위해 실시했다. 비산불 지역과 산화적지를 대상으로 산림토양의 수저류능을 토양공극, 최대수분량, 이용가능수량, 그리고 투수율을 측정하여 비교 분석하였다. 주요 인자들의 측정에 의해서 얻어진 결과는 다음과 같다. 산화적지와 대조구에서 토성이 깊어질수록 전공극(全孔隙), 조공극(組孔隙), 이용가능 수량, 투수율은 모두 감소하는 경향을 나타내고, 세공극(細孔隙)은 약간 증가하는 경향이 있었다. 대조구에 비해 산화적지에서는 투수율, 조공극량 및 이용가능수량이 낮게 나타나는 반면, 세공극량은 높게 나타났다. 그리고 산불이 발생한 직후에는 산림토양의 공극량 분포에 큰 변화가 일어나지 않지만, 시간이 경과함에 따라 산화적지의 표토 공극분포에 변화를 일으키면서 서서히 토심 20-40cm까지 영향을 미치는 것으로 나타났다. 또한 토심변화에 따른 이용가능수량의 변화는 대조구에 비해 산화적지에서 상대적으로 큰 폭으로 감소하는 경향이 있었다. 이 결과로 산림의 수저류능은 산불에 의해 크게 영향을 받는 것을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1175-1184
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• 2022

The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (D_S) and the pore volume fractal dimension (D_V). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample's pore structure and the dissolution rate during the leaching was fitted.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.271-276
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• 2002

Continuous loading is applied the sample has been developed to overcome some of the problems associated with the incremental loading consolidation test. Therefore, it is able to reduce the test time and provide a well defined the curve of effective stress versus strain due to continuous stress-strain points. Also, the constant rate of strain consolidation(CRSC) test has been accepted widely as a standard method in foreign countries because of its many advantages. However, in Korea the CRSC test has not been used in engineering practice and experimentally verified. Because there is not a precise criterion of testing despite consolidation characteristics are influenced on strain rate and Pore pressure ratio. Consequently, it is difficult to apply in engineering practice. In this study, artificial neural networks are applied to the estimation of th proper strain rate and pore pressure ratio of the CRSC test. This study shows the possibility of utilizing the artificial neural networks model of estimation of the strain rate and pore pressure ratio in the CRSC test.

• Advances in concrete construction
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• 제16권3호
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• pp.141-153
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• 2023

In order to develop and take full advantage of pasture fiber and waste concrete, this article studied how different amounts of pasture fiber influenced the toughness and pore structure of concrete with different replacement rates of recycled fine aggregate. Pasture fiber recycled concrete constitutive equations were established under idealized stiffness and toughness damage rate, based on fracture energy and damage mechanics theories. The relationship between pore structure and toughness was studied utilizing nuclear magnetic resonance and fractal theory. The toughness of text groups (0% (JZ), 10% (ZS10), 20% (ZS20)) first increased and then decreased with increasing amounts of pasture fiber, based on the damage rate of toughness. The toughness of concrete samples with recycled fine aggregate and pasture fiber is negatively correlated to the fractal dimension of small and medium-sized pores with a pore size of 0-500 nm. At a replacement rate of 10% of the recycled fine aggregate, the fractal dimension of the air voids (r: 500-9000 nm, i.e., Lg(r) ∈ [2.7, 3.9]) shows a gradual decrease with the increase of grass fiber dosage, indicating that with such a replacement rate of the recycled fine aggregate, the increase of pasture fiber can reduce the complexity of the pore structure of the air voids (500-9000 nm).

• 한국염색가공학회지
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• 제14권6호
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• pp.305-312
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• 2002

In order to give a silk-like touch to PET fabrics, the PET fabrics were treated with NaOH alkaline solution in various conditions. In alkaline treatment, the liquor flow type pilot weight reduction apparatus with magnetostrictive ultrasonic transducer was used for the study. The effects of ultrasonic application, treatment time and temperature at NaOH 4% and 6"A solution on the decomposition rate of PET fabrics. From the results of the decomposition rate of PET fabrics, the qualitative and quantitative analysis of oligomer after decomposition of PET fabrics carried out by the HPLC. On the other hand, the surface pore characteristics of decomposition PET fabrics measured by porosimetery. The pore characteristics on the surface of treated PET fiber depended on the decomposition rate and did not depend on the ultrasonic cavitation. The pore diameter of alkaline untreated PET fiber were 15A and those of treated PET fibers were 5~6$\AA$ at the maximum pore volume. The average pore sizes of fiber before and after treatment were 141 h and 160h, respectively. Total amount of oligomer of the untreated PET fibers were 1.70wt% and 67.7% of total oligomer occupied with PET cyclic trimer and PET cyclic tetramer. Total amount of oligomer of fiber with 26.9% and 48.0% of weight loss without ultrasonic application were 1.78wt% and 1.79wt%, respectively. Also total amount oligomer of fibers which were reduced 27.7% and 48.2% of weight loss with ultrasonic application were 1.74wt%. This result showed that the removal rate of oligomer in the process of alkaline hydrolysis with ultrasonic higher than that of without ultrasonic application.tion.