• Journal of Hydrogen and New Energy
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• v.31 no.5
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• pp.453-458
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• 2020

In this study, ethylene-propylene-diene monomer (EPDM) rubbers reinforced with various particle size of carbon black were prepared and tested. We followed recently published CSA/ANSI CHMC2 standard "the test methods for evaluating material compatibility in compressed hydrogen applications-polyemr". Measurement of change in hardness, tensile strength and volume were performed after exposure to maximum operating pressure, 87.5 MPa, for 168 hours (1 week). Once EPDM was exposed to high-pressure hydrogen, the samples experience volume increase and degradation of the physical properties. Also, after the dissolved hydrogen was fully eliminated from the specimens, the hardness and the tensile properties were not recovered. The rubber reinforced with smaller sizes of carbon black particles showed less volume expansion and decrease of physical properties. As a result, smaller particle size of carbon black filler led to more resistance to high-pressure hydrogen.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.531-539
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• 2008

The purpose of this study is to investigate the mechanical properties of high strength concretes reinforced with hooked steel fiber. For this purpose, total 36 specimens whose variables are concrete compressive strength, steel fiber aspect ratio, and steel fiber volume contents, are made and tested. From the test results including previous research work, flexural performance of steel fiber reinforced high strength concrete is evaluated in terms of flexural strength and toughness index. Flexural behavior of steel fiber reinforced high strength concrete is enhanced with respect to the fiber volume content, the aspect ratio, and concrete compressive strength. More efforts are devoted to evaluate quantitatively between the flexural strength and the structural parameters such as the fiber volume content, the aspect ratio, and concrete compressive strength.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.3
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• pp.589-597
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• 1992

The effect of pressure on soot formation in premixed propane-air combustion is investigated at high pressures over the pressure range of 1 to 5 MPa by using a specially designed constant volume combustion bomb. The combustiom chamber of disk type with eight spark plugs located on the circumference at an interval of 45deg is 100mm in diameter by 14mm thick. The end gases are compressed to high pressures by the eight converging flames. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in-situ laser extinction technique, and the burnt gas temperature during the same period is measured by the two-color method. It is found that the soot yield rises with 50 to 100% for the respective equivalence ratio range of 1.9-2.2 at an interval of 0.1 when the combustion pressure is increased from 1 to 5 MPa, and that the turbulent flames decrease in the soot yield as compared with the laminar flames because the burnt gas temperatures increase with the drop of heat loss.

• Journal of the Korean Dietetic Association
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• v.28 no.3
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• pp.195-204
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• 2022

The purpose of this study was to provide nutritional information for selecting beverages with low sugar contents. The nutritional data, including the sugar contents of 925 beverages, were collected from the nutrition labels through the official websites of manufacturers and analyzed according to the beverage types. The average price and volume of the beverage products were 1,556.6 won and 224.8 mL, respectively. The volume per price was the highest for carbonated beverages at 351.6 mL/1,000 won. The sugar content was high in the order of carbonated beverages (22.6 g), fruit & vegetable beverages (21.0 g), and mixed beverages (19.1 g). The sugar content per 100 mL was high in the order of fruit juice (10.6 g), fruit and vegetable beverages (9.2 g), ginseng and red ginseng beverages (8.5 g), and mixed beverages (8.3 g). The content of the product per 1,000 won was high in the order of carbonated beverages (23.3 g), fruit and vegetable beverages (23.2 g), and mixed beverages (20.0 g). The number of products with energy from a sugar content of 5% or more compared to the energy reference value was significantly higher in the carbonated beverages (52.2%), fruit and vegetable beverages (33.0%), and mixed beverages (26.5%) than other beverages. The sugar energy ratio of beverage products was highest in the carbonated beverages at 88.9%, followed by fruit and vegetable beverages (87.0%), fruit juices (84.3%), and mixed beverages (76.8%). Overall, beverages with high sugar contents per product, volume, and price were carbonated beverages, fruit and vegetable beverages, and mixed beverages.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.111-120
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• 2024

This paper presents a study aimed at developing repair materials for emergency slope stabilization after disasters such as floods. The research assessed how different mix ratios of fly ash and reinforcement with basalt fibers affect the basic quality properties of mortars. Optimal amounts of fly ash were selected based on these properties, and appropriate amounts of chemical admixtures and thickeners were determined to enhance the quality attributed to the basalt fiber mixture. Notably, high-volume fly ash reduced the need for high-performance water reducers and improved workability, known benefits that also helped mitigate fiber ball issues in conjunction with the effects of thickeners. The experimental results indicated that the developed repair materials could potentially be used for emergency repairs, with a focus on initial age strength. This research aims to provide foundational data for repair materials used in future emergency slope stabilizations.

• Clean Technology
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• v.30 no.1
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• pp.23-27
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• 2024

Bismuth is a promising anodic for Li-ion batteries (LIBs) due to its adequate operating voltage and high-volume capacity (3,765 mAh cm^-3). Nevertheless, inevitable volume expansion during Bi alloy reactions leads to severe capacity loss and cell destruction. To address this, a complex of bismuth alloy nanoparticles (Bi@NC) embedded in an N doping-carbon coating is fabricated via a simple pyrolysis method. Nano-sized bismuth alloys can improve the reaction dynamics through a shortened Li⁺-ion diffusion path. In addition, the N-doped carbon coating effectively buffers the volume change of bismuth during the extended alloy/dealloy reaction with Li⁺ ions and maintains an effective conductive network. Based on the Thermogravimetric analysis (TGA) showed high bismuth alloy loading (80.9 wt%) and maintained a high gravimetric capacity of 315 mAh g^-1 up to 100 cycles with high volumetric capacity of 845.6 mAh cm^-3.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.1
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• pp.28-35
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• 2023

Objective: The purpose of this study was to evaluate the effectiveness of middle meningeal artery embolization (MMAE) in elderly high-risk patients with symptomatic chronic subdural hematoma (CSDH) in terms of reduction in hematoma volume and recurrence rate. Methods: We retrospectively reviewed data prospectively collected from nine patients who underwent 13 MMAE for CSDH between June 2017 and May 2022. The volume of the subdural hematoma was measured using a computer-aided volumetric analysis program. Hematoma volume changes during the follow-up period were analyzed and clinical outcomes were evaluated. Results: The mean follow-up period was 160 days (range, 46-311 days). All procedures were technically successful and there were no procedure-related complications. Of the 13 MMAE, 84% (11 out of 13 hemispheres) showed mean 88% of reduction on follow-up volumetric study with eight cases of complete resolution. There was one refractory case with MMAE which had been performed multiple burr-hole trephinations, for which treatment was completed by craniotomy and meticulous resection of multiple pseudomembranes. There was no recurrent case during the follow-up period, except for refractory case. Conclusions: MMAE for CSDH in selected high-risk elderly patients and relapsed patients might be effective. Despite the small cohort, our findings showed a high rate of complete resolution with no complications. Further prospective randomized trials are warranted to evaluate its usefulness as a primary treatment option for CSDH.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.5
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• pp.441-449
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• 2000

Binary volume data has its widespread use in the application of color volume rendering and surgical simulation system where gray-scale volume is inappropriate. For the efficient representation of binary volume, this paper proposes a new data structure - the Slice-based Binary Shell (SBS) - along with its rendering algorithm. Since SBS stores the minimal set of surface voxels in slice order and supports the direct computation of voxel coordinates, it shows high efficiency for rendering multiple objects. The rendering algorithm of SBS running on a PC with no specialized hardware renders more than one hundred binary objects in a second.

• Journal of Environmental Science International
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• v.20 no.8
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• pp.977-986
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• 2011

This study analyzed the characteristics of stormwater runoff in the orchard areas and quantitatively estimated effluence of nonpoint source pollutants for the volume of runoff. Two target areas under vine cultivation were each $2,000m^2$ and $1,800m^2$, located in Gyeongju City. Since grape was the only crop on the target area, the characteristics of stormwater runoff at vineyard could be evaluated independently. A total of 51 rainfall events in the vineyard area during two years(2008-2009) was surveyed, and 19 of them became stormwater runoff, with rainfall ranging 16.5 - 79.7 mm and antecedent dry period of 1-13 days. The pollutant runoff loads by volume of stormwater runoff showed BOD ranging 19.5 - 45.3% in 30% of runoff volume. The average pollution discharge rate was 32.4%, indicating small first flush effect of BOD. The range of SS concentrations was 5 - 52.0% in 10% of runoff volume, showing the average 28.7% of discharge rate, about 3 times more than rainfall effluent. TOC and TN appeared to be similar to the results of BOD, the average discharge rate of 30.9% and 30.6% for TOC and TN, respectively, for 30% of stormwater runoff volume. Average discharge rate of COD and TP in the same runoff volume was 35.1% and 36%, respectively, showing comparatively high discharge ratio. As the targeted vineyard area was permeable land, the pollution load ratio against rainfall-runoff volume appeared to be 1:1, implying no strong first flush effect for all the survey items.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.599-607
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• 2015

In this study, we theoretically investigate the thermal performances of heat pipes that have different nano-fluid properties. Two different types of nano-particles have been used: $Al_2O_3$ and CuO. The thermal performances of the heat pipes are observed for varying nano-particle aggregations and volume fractions. Both the viscosity and the conductivity increase as the volume fraction and the aggregation increase, respectively. Increasing the volume fraction helps increase the capillary limit in the well-dispersed condition. Whereas, the capillary limit is decreased under the aggregate condition, when the volume fraction increases. The dependence of the heat pipe thermal resistance on the volume fraction, aggregation, and conductivity of the nano-particles is analyzed. The maximum thermal transfer of the heat pipe is highly dependent on the volume fraction because of the high permeability of the heat pipe. For the proposed heat pipe, the optimum volume fraction of the nano-particle can be seen through 3D graphics.