• Computers and Concrete
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• v.21 no.6
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• pp.717-726
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• 2018

Concrete pipelines are the most efficient and safe means for gas and oil transportation over a long distance. The use of nano materials and nono-engineering can be considered for enhancing concrete pipelines properties. the tests show that $SiO_2$ nanoparticles can improve the mechanical behavior of concrete. Moreover, severe hazard for pipelines is seismic ground motion. Over the years, scientists have attempted to understand pipe behavior against earthquake most frequently via numerical modeling and simulation. Therefore, in this paper, the dynamic response of underwater nanocomposite submerged pipeline conveying fluid is studied. The structure is subjected to the dynamic loads caused by earthquake and the governing equations of the system are derived using mathematical model via Classic shell theory and Hamilton's principle. Navier-Stokes equation is employed to calculate the force due to the fluid in the pipe. As well, the effect of external fluid is modeled with an external force. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite. 1978 Tabas earthquake in Iran is considered for modelling seismic load. The dynamic displacement of the structure is extracted using differential quadrature method (DQM) and Newmark method. The effects of different parameters such as $SiO_2$ nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios, internal and external fluid pressure and earthquake intensity are discussed on the seismic response of the structure. From results obtained in this paper, it can be found that the dynamic response of the pipe is increased in the presence of internal and external fluid. Furthermore, the use of $SiO_2$ nanoparticles in concrete pipeline reduces the displacement of the structure during an earthquake.

• Computers and Concrete
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• v.24 no.2
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• pp.125-135
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• 2019

Concrete pipelines are the most efficient and safe means for gas and oil transportation over a long distance. The use of nano materials and nono-engineering can be considered for enhancing concrete pipelines properties. the tests show that SiO2 nanoparticles can improve the mechanical behavior of concrete. Moreover, severe hazard for pipelines is seismic ground motion. Over the years, scientists have attempted to understand pipe behavior against earthquake most frequently via numerical modeling and simulation. Therefore, in this paper, the dynamic response of underwater nanocomposite submerged pipeline conveying fluid is studied. The structure is subjected to the dynamic loads caused by earthquake and the governing equations of the system are derived using mathematical model via Classic shell theory and Hamilton's principle. Navier-Stokes equation is employed to calculate the force due to the fluid in the pipe. As well, the effect of external fluid is modeled with an external force. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite. 1978 Tabas earthquake in Iran is considered for modelling seismic load. The dynamic displacement of the structure is extracted using differential quadrature method (DQM) and Newmark method. The effects of different parameters such as SiO2 nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios, internal and external fluid pressure and earthquake intensity are discussed on the seismic response of the structure. From results obtained in this paper, it can be found that the dynamic response of the pipe is increased in the presence of internal and external fluid. Furthermore, the use of SiO2 nanoparticles in concrete pipeline reduces the displacement of the structure during an earthquake.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.1-9
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• 2022

Purpose: In this study, we used hydrophilic waterstop used in geosynthetics vertical barrier system to evaluate the performance of impermeability under sealing conditions. Method: ASTM D5887 and ASTM D6766 were applied to determine the capability of the connection during the geosynthetics vertical barrier system. Hydrophilic waterstop was saturated in each solution and the weight, thickness, and volume changes were analyzed over elapsed time. Hydrophilic waterstop was installed at the geosynthetics vertical barrier system connection to evaluate the permeability characteristics. Results: As the expansion reaction time of hydrophilic waterstop increased relatively under saline conditions, the decrease in permeability also showed a smaller decrease in fresh water. Furthermore, the method of engagement of the geosynthetics vertical barrier system showed somewhat better performance of the impermeability due to the large pressure resistance caused by the roll joint type than interlock type. Conclusion: In urban pollutants, which can estimate the outflow of pollutants such as oil storage facilities and industrial complexes, proactive response technologies that can prevent the contaminant diffusion can significantly reduce the damage.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.385-399
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• 2021

Among human-induced seismicity, fluid production has been one of the causes. In this report, the mechanism that causes an earthquake due to a decrease in the fluid pressure inside the reservoir during fluid extraction is summarized. As case studies, the Lacq gas field in France, the Cerro Prieto geothermal field in Mexico, and the Groningen gas field in the Netherlands, which have become issue recently, were introduced. It is showed that fluid production, ground subsidence, and the presence of existing faults were closely related with the induced seismicity. Therefore, for the development of oil or gas field and geothermal field, it is important to investigate the presence of faults that may cause earthquakes in the reservoir, to monitor ground subsidence during production in real time, and to control production.

• Transactions of Materials Processing
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• v.31 no.2
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• pp.51-56
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• 2022

In this study, finite element analyses were performed by applying a stress ring and split die design to relieve the tensile stress acting on the die due to high surface pressure during warm-closed forging. The applied material was a yield-ratio-control-steel (YRCS). It was used without quenching or tempering after forging. In the case of stress rings design, the number of stress rings and the tolerance for shrink fit were different. Vertical and horizontal splits were applied for insert die split design. Case 5 die with three stress rings, 0.2 % shrink fit tolerance, and vertical split was selected as an effective die design for tensile stress reduction. Based on die stress reduction analyses, Case 5 die for warm-closed forging was produced and smooth forgeability was secured, making it possible to manufacture forging product of yoke with the required geometry. In addition, controlled cooling using warm forging heat was applied to secure mechanical properties of yokes. When oil cooling was used for direct controlled cooling after warm-closed forging, a relatively uniform Rockwell hardness distribution and high mechanical properties could be obtained.

• Korean Journal of Pharmacognosy
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• v.53 no.3
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• pp.138-144
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• 2022

Obesity is a disease in which an abnormally large amount of fat accumulates in the body. Various diseases such as type 2 diabetes, dyslipidemia, high blood pressure, fatty liver, gallbladder disease, and coronary artery disease are induced. In this study, we investigated the effect of betaone, a type of barley, on obesity suppression. After the betaone extract was treated with 3T3 L1 adipocytes, the effect on adipocyte formation was investigated through Oil Red O staining. It was observed that differentiation was inhibited without affecting the viability of 3T3 L1 adipocytes. The effect of betaone extract on obesity inhibition in a mouse model was investigated. As a result of administering betaone extract after a high-fat diet, it was confirmed that the level of blood sugar and body weight was decreased, and glucose uptake ability was improved in a glucose tolerance test. The formation of mouse adipose tissue was suppressed, and the expression of genes involved in the formation and degradation of obesity in liver tissue was improved. These results suggest that betaone extract is a useful substance for improving obesity and is an excellent material for health functional food.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.104-114
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• 2022

The purpose of using coolant in machining is both to increase a tool life and also to prevent product deformation and thus, stabilize the surface quality by lubricating and cooling the tool and the machining surface. However, a very small amount of cutting mist should be used because chlorine-based extreme pressure additives are used to generate environmental pollutants in the production process and cause occupational diseases of workers. In this study, medical titanium alloy (Ti-6Al-7Nb) was subjected to a processing experiment by selecting factors and levels affecting cutting power in the processing of the Aerosol Dry Lubrication (ADL) method using vegetable oil. The machining shape was a slot to sufficiently reflect the effect of the cutting depth. As for the measurement of cutting force, the trend of cutting characteristics was identified through complete factor analysis. The factors affecting the cutting force of ADL slot processing were identified using the reaction surface analysis method, and the characteristics of the cutting force according to the change in factor level were analyzed. As the cutting speed increased, the cutting force decreased and then increased again. The cutting force continued to increase as the feed speed increased. The increase in the cutting depth increased the cutting force more significantly than the increase in the cutting speed and the feed speed. Through the reaction surface analysis method, the regression equation for predicting cutting force was identified, and the optimal processing conditions were proposed. The cutting force was predicted from the secondary regression equation and compared with the experimental value.

• Journal of Drive and Control
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• v.20 no.2
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• pp.40-46
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• 2023

Fresh corn, one of the main food crops, must be harvested by hand. A harvest mechanization technology is required. In this study, a tractor-attached harvester was designed and manufactured to sequentially perform stem reaping, fresh corn detaching, and collecting. The(harvester was designed so that the main device could operate through a hydraulic pump and a generator could be operated through the tractor's PTO. Factor tests were conducted according to cultivars (Ilmichal, Super sweet corn) and working speed (0.12 m/s, 0.17, 0.22). After the factor test, detached corns ratio, collected corns ratio, and damaged corns ratio were analyzed and harvest performance was evaluated. Harvesting performance was good for super sweet corn. Considering operation efficiency, 0.22 m/s was judged to be an appropriate working speed. It was found that it took two hours to work an area of 10 a.

• Geomechanics and Engineering
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• v.34 no.4
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• pp.409-424
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• 2023

Response of the pipeline crossing fault is considered as the large strain problem. Proper estimation of the pipeline response plays important role in mitigation studies. In this study, an advanced continuum modeling including material non-linearity in large strain deformations, hardening/softening soil behavior and soil-pipeline interaction is applied. Through the application of a fully nonlinear analysis based on an explicit finite difference method, the mechanics of the pipeline behavior and its interaction with soil under large strains is presented in more detail. To make the results useful in oil and gas engineering works, a continuous pipeline of two steel grades buried in two clayey soil types with four different crossing angles of 30°, 45°, 70° and 90° with respect to the pipeline axis have been considered. The results are presented as the fault movement corresponding to different damage limit states. It was seen that the maximum affected pipeline length is about 20 meters for the studied conditions. Also, the affected length around the fault cutting plane is asymmetric with about 35% and 65% at the fault moving and stationary block, respectively. Local buckling is the dominant damage state for greater crossing angle of 90° with the fault displacement varying from 0.4 m to 0.55 m. While the tensile strain limit is the main damage state at the crossing angles of 70° and 45°, the cross-sectional flattening limit becomes the main damage state at the smaller 30° crossing angles. Compared to the stiff clayey soil, the fault movement resulting 3% tensile strain limit reach up to 40% in soft clayey soil. Also, it was seen that the effect of the pipeline internal pressure reaches up to about 40% compared to non-pressurized condition for some cases.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.189-198
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• 2009

Recently the concern about the construction of underground structures such as oil and food storage caverns is increasing in Korea and abroad. The stability of those underground caverns is greatly influenced by shape factor and the size of excavation area as well as the joint conditions. In this study, therefore, the effect of the shape factor of an underground cavern on its stability was analyzed in terms of safety factor. To this end, four different shape factors of a cavern excavated in good rock conditions were investigated and sensitivity analyses were performed based on overburden, lateral earth pressure coefficient, joint spacing, properties, and orientation. The stability of a cavern is evaluated in terms of safety factor estimated numerically based on the shear strength reduction technique. In future, this study is expected to be helpful in designing and evaluating the stability of caverns excavated in discontinuous rock masses.