• Smart Structures and Systems
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• v.23 no.6
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• pp.653-667
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• 2019

Using cross-ties to connect cables together when forming a cable network is regarded as an efficient method of mitigating cable vibrations. Cross-ties have been extended and fixed on bridge decks or towers in some engineering applications. However, the dynamics of this kind of system need to be further studied, and the effects of extending cross-links to bridge decks/towers on the modal response of the system should be assessed in detail. In this paper, a system of two cables connected by an inter-supported cross-link with another lower cross-link extended to the ground is proposed and analyzed. The characteristic equation of the system is derived, and some limiting solutions in closed form of the system are derived. Roots of cable system with special configurations are also discussed, attention being given to the case when the two cables are identical. A predictable mode behavior was found when the stiffness of inter-connection cross-link and the cross-link extended to the ground were the same. The vector of mode energy distribution and the degree of mode localization index are proposed so as to distinguish global and local modes. The change of mode behaviors is further discussed in the case when the two cables are not identical. Effects of cross-link stiffness, cross-link location, mass-tension ratio, cable length ratio and frequency ratio on $1^{st}$ mode frequency and mode shape are addressed.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.535-543
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• 2019

Building on/with expansive soils with no treatment brings complications. Compacted expansive soils specifically fall short in satisfying the minimum requirements for transport embankment infrastructures, requiring the adoption of hauled virgin mineral aggregates or a sustainable alternative. Use of hauled aggregates comes at a high carbon and economical cost. On average, every 9m high embankment built with quarried/hauled soils cost $12600MJ.m^{-2}$ Embodied Energy (EE). A prospect of using mixed cutting-arising expansive soils with industrial/domestic wastes can reduce the carbon cost and ease the pressure on landfills. The widespread use of recycled materials has been extensively limited due to concerns over their long-term performance, generally low shear strength and stiffness. In this contribution, hydromechanical properties of a waste tyre sand-sized rubber (a mixture of polybutadiene, polyisoprene, elastomers, and styrene-butadiene) and expansive silt is studied, allowing the short- and long-term behaviour of optimum compacted composites to be better established. The inclusion of tyre shred substantially decreased the swelling potential/pressure and modestly lowered the compression index. Silt-Tyre powder replacement lowered the bulk density, allowing construction of lighter reinforced earth structures. The shear strength and stiffness decreased on addition of tyre powder, yet the contribution of matric suction to the shear strength remained constant for tyre shred contents up to 20%. Reinforced soils adopted a ductile post-peak plastic behaviour with enhanced failure strain, offering the opportunity to build more flexible subgrades as recommended for expansive soils. Residual water content and tyre shred content are directly correlated; tyre-reinforced silt showed a greater capacity of water storage (than natural silts) and hence a sustainable solution to waterlogging and surficial flooding particularly in urban settings. Crushed fine tyre shred mixed with expansive silts/sands at 15 to 20 wt% appear to offer the maximum reduction in swelling-shrinking properties at minimum cracking, strength loss and enhanced compressibility expenses.

• Journal of The Korean Astronomical Society
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• v.52 no.1
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• pp.1-9
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• 2019

We present the results of the spectral and temporal analysis of eight X-ray point sources in five nearby (distance < 20 Mpc) galaxies observed with Chandra. For spectral analysis, an absorbed powerlaw and an absorbed diskblackbody were used as empirical models. Six sources were found to be equally fitted by both the models while two sources were better fitted by the powerlaw model. Based on model parameters, we estimate the X-ray luminosity of these sources in the energy range 0.3 - 10.0 keV, to be of the order of ${\sim}10^{39}ergs\;s^{-1}$ except for one source (X-8) with $L_X>10^{40}ergs\;s^{-1}$. Five of these maybe classified as Ultraluminous X-ray sources (ULXs) with powerlaw photon index within the range, ${\Gamma}{\sim}1.63-2.63$ while the inner disk temperature, kT ~ 0.68 - 1.93 keV, when fitted with the disk blackbody model. The black hole masses harboured by the X-ray point sources were estimated using the disk blackbody model to be in the stellar mass range, however, the black hole mass of one source (X-6) lies within the range $68.37M_{\odot}{\leq}M_{BH}{\leq}176.32M_{\odot}$, which at the upper limit comes under the Intermediate mass black hole range. But if the emission is considered to be beamed by a factor ~ 5, the black hole mass reduces to ${\sim}75M_{\odot}$. The timing analysis of these sources does not show the presence of any short term variations in the kiloseconds timescales.

• The Journal of Sustainable Design and Educational Environment Research
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• v.17 no.3
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• pp.35-45
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• 2018

The purpose of this study is to analyze the types of present situation data related to school facilities through existing literature and related systems and to develop indicators related to improvement of educational environment that can have an important influence on students' education and life in general. In this study, we conducted a second Delphy Survey to establish the educational environment improvement index. As a result, a total of 88 education environment improvement indicators were set, including 43 indicators on the quantitative aspects of the area, adequacy of general classrooms, and appropriateness of multi-purpose steel sugar, 34 indicators on the qualitative aspects such as the level of seismic performance, age of fire facilities, aging of toilets, and aging of finishing materials, and 11 indicators on operational aspects such as energy usage and user satisfaction.

• Earthquakes and Structures
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• v.15 no.6
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• pp.617-627
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• 2018

After earthquakes FRP sheets are often used for the rehabilitation of damaged Reinforced Concrete (RC) beamcolumn connections. Connections with minor to moderate damage are often dealt with by applying FRP sheets after a superficial repair of the cracks using resin paste or high strength mortar but without infusion of thin resin solution under pressure into the cracking system. This technique is usually adopted in these cases due to the fast and easy-to-apply procedure. The experimental investigation reported herein aims at evaluating the effectiveness of repairing the damaged beam-column connections using FRP sheets after a meticulous but superficial repair of their cracking system using resin paste. The investigation comprises experimental results of 10 full scale beam-column joint specimens; five original joints and the corresponding retrofitted ones. The repair technique has been applied to RC joints with different joint reinforcement arrangements with minor to severe damage brought about by cyclic loading for the purposes of this work. Aiming at quantitative concluding remarks about the effectiveness of the repair technique, data concerning response loads, loading stiffness and energy absorption values have been acquired and commented upon. Furthermore, comparisons of damage index values and values of equivalent viscous damping, as obtained during the test of the original specimens, with the corresponding ones observed in the loading of the repaired ones have also been evaluated and commented. Based on these comparisons, it is deduced that the technique under investigation can be considered to be a rather satisfactory repair technique for joints with minor to moderate damage taking into account the rapid, convenient and easy-to-apply character of its application.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1390-1397
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• 2019

SiC coating and SiC/glassy carbon composite coating were prepared on IG-110 nuclear graphite (Toyo Tanso Co., Ltd., Japan) to strengthen its inertness to molten fluoride salt used in molten salt reactor (MSR). Two kinds of modified graphite were obtained and correspondingly named as IG-110-1 and IG-110-2, which referred to modified IG-110 with a single SiC coating and a SiC/glassy carbon composite coating, respectively. Both structure and property of modified graphite were carefully researched and contrasted with virgin IG-110. Results indicated that modified graphite presented better comprehensive properties such as more compact structure and higher resistance to molten salt infiltration. With the protection of coatings, the infiltration amounts of fluoride salt into modified graphite were much less than that into virgin IG-110 at the same circumstance. Especially, the infiltration amount of fluoride salt into IG-110-2 under 5 atm was merely 0.26 wt%, which was much less than that into virgin IG-110 under 1.5 atm (13.5 wt%) and the critical index proposed for nuclear graphite used in MSR (0.5 wt%). The SiC/glassy carbon composite coating gave rise to highest resistance to molten salt infiltration into IG-110-2, and thus demonstrated it could be a promising protective coating for nuclear graphite used in MSR.

• Advances in nano research
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• v.7 no.4
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• pp.249-263
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• 2019

In the current paper, an exact solution method is carried out for analyzing the thermo-mechanical vibration of curved FG nano-beams subjected to uniform thermal environmental conditions, by considering porosity distribution via nonlocal strain gradient beam theory for the first time. Nonlocal strain gradient elasticity theory is adopted to consider the size effects in which the stress for not only the nonlocal stress field but also the strain gradients stress field is considered. It is perceived that during manufacturing of functionally graded materials (FGMs) porosities and micro-voids can be occurred inside the material. Material properties of curved porous FG nanobeam are assumed to be temperature-dependent and are supposed to vary through the thickness direction of beam which modeled via modified power-law rule. Since variation of pores along the thickness direction influences the mechanical and physical properties, porosity play a key role in the mechanical response of curved FG nano-structures. The governing equations and related boundary condition of curved porous FG nanobeam under temperature field are derived via the energy method based on Timoshenko beam theory. An analytical Navier solution procedure is utilized to achieve the natural frequencies of porous FG curved nanobeam supposed to thermal loading. The results for simpler states are confirmed with known data in the literature. The effects of various parameters such as nonlocality parameter, porosity volume fractions, thermal effect, gradient index, opening angle and aspect ratio on the natural frequency of curved FG porous nanobeam are successfully discussed. It is concluded that these parameters play key roles on the dynamic behavior of porous FG curved nanobeam. Presented numerical results can serve as benchmarks for future analyses of curve FG nanobeam with porosity phases.

• Nutrition Research and Practice
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• v.13 no.3
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• pp.214-221
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• 2019

BACKGROUNDS/OBJECTIVES: Cancer treatment may lead to significant body composition changes and affect growth and disease outcomes in pediatric cancer patients. This prospective study aimed to evaluate short- and long-term body compositions changes focused on body fat during the first year of cancer treatment in children. SUBJECTS/METHODS: A prospective study was conducted in 30 pediatric cancer patients (19 hematologic malignancies and 11 solid tumors) and 30 age- and sex-matched healthy controls. Anthropometric measurements and body composition analysis using whole body dual energy X-ray absorptiometry were performed at baseline and 1, 6, and 12 month(s) of cancer treatment. Kruskal-Wallis tests, Wilcoxon paired t tests, and generalized estimation equation (GEE) were applied for statistical analysis. RESULTS: At baseline, no differences in weight, height, body mass index, abdominal circumferences, body fat, and fat-free mass were observed between 30 controls and 30 pediatric cancer patients. Total fat mass (P < 0.001) and body fat percentage (P = 0.002) increased significantly during the first month, but no changes were observed from 1 to 12 months; however, no changes in the total mass were observed during the first year of cancer treatment. Meanwhile, the total fat-free mass decreased during the first month (P = 0.008) and recovered between 6 and 12 months of follow-up (P < 0.001). According to GEE analysis, there was a significant upward trend in body fat percentage during the first year, especially the first month, of cancer treatment in children with hematologic malignancies, but not in those with solid tumors. CONCLUSIONS: Our results indicate that cancer treatment is related to significant body composition changes and rapid body fat gain, particularly during the first month after initiating cancer treatment, in children with hematologic malignancies. Therefore, individualized dietary strategies to prevent excessive fat gain are needed in pediatric cancer patients for better outcomes.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.225-234
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• 2019

The purpose of this paper is to analyze the additional construction cost of G-SEED certification for domestic office building reflecting the latest standard(G-SEED 2016-2), and to derive cost impact by category and level. Therefore, it is intended to provide quantitave cost data according to G-SEED certification at the planning phase of the project, estimate the additional construction cost per level according to G-SEED Certification of similar project to be carried out in the future, and encourage G-SEED certification by supporting the decision of the owners. Method: The Process and method of this study are summarized in five steps, 1) Review of previous research, 2) Selection of target project, 3) Scenario setting by level, 4) Additional construction cost for each evaluation category, 5) Extraction of additional construction cost ratio by level. Result: This paper analyzed the cost impact by deriving the additional construction cost of detailed category for level improvement according to the revised G-SEED certification(G-SEED 2016-2). In conclusion, an additional construction cost(ratio) of G-SEED projects to the reference building is drawn as good level; 157,426,241 KWN(+0.43%), very good level; 321,907,802 KWN(+0.88%), excellent level; 999,371,478 KWN(+2.74%), and outstanding level; 1,467,047,718 KWN(+4.02%).

• Journal of Environmental Science International
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• v.30 no.6
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• pp.487-500
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• 2021

To evaluate the geochemical characteristics and assess the pollution in surface sediments of the Nakdong River estuary, two sites adjacent to the estuary bank (Hh1 and Hh2) and one site at the upper part of the estuary bank (Hh3) were investigated. The surface sediments were analyzed for their contents of metals (Cu, Pb, Ni, Cr, Zn, and Al), organic matter (IL, COD, TOC, and TN), and grain size from 2018 to 2020. As a result of the pollution assessment, there was little anthropogenic contamination by most of the metals. The surface sediments in Hh2 had comparatively abundant silt and clay, whereas the other sites were mainly composed of sand. The organic index and contents of organic matter were highest at Hh2. Multivariate statistical analyses (cluster analysis and Pearson correlation analysis) showed that the contents of organic matter and pollution were associated with fine sediment. These results suggest that the geochemical characteristics were changed by the estuary bank built in the research area and that the increase in fine sediment attributable to the low-energy environment resulted in an increase in organic matter pollution.