• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3478-3487
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• 2022

In this study, we incorporate an anisotropic scattering scheme involving spherical harmonics into the method of characteristics (MOC). The neutron transport solution in a light water reactor can be significantly improved because of the impact of an anisotropic scattering source with the MOC flat source approximation. Several problems are selected to verify the proposed scheme and investigate its effects and accuracy. The MOC anisotropic scattering source is based on the expansion of spherical harmonics with Legendre polynomial functions. The angular flux, scattering source, and cross section are expanded in terms of the surface spherical harmonics. Later, the polynomial is expanded to achieve the odd and even parity of the source components. Ultimately, the MOC angular and scalar fluxes are calculated from a combination of two sources. This paper presents various numerical examples that represent the hot and cold conditions of a reactor core with boron concentration, burnable absorbers, and control rod materials, with and without a reflector or baffle. Moreover, a small critical core problem is considered which involves significant neutron leakage at room temperature. We demonstrate that an anisotropic scattering source significantly improves solution accuracy for the small core high-leakage problem, as well as for practical large core analyses.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.529-536
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• 2011

Recently, there has been a growing interest in expanded sidewalks for existing bridges. The cantilever beam system applied to expanded sidewalks for existing bridges are connected with the concrete structure by adhesive anchor bolts. However, the extended sidewalks are currently constructed without standardized regulations, which lead to excessive design of the beam spacing and installation and the construction difficulties due to the excessive over-weight. Moreover, there is only limited analysis and experiment data on the post-installed adhesive anchor bolts, so the excessive number of bolts is used for the connection. This paper deals with a method to increase the effectiveness of beam sections and anchor bolts geometry for expanded sidewalk of existing bridge. The study results showed that the failure of cantilever beam connected by adhesive anchor bolts was dominated by bond failure of interface between concrete and bolt. Also, the results indicated the possibilities of improving serviceability as well as safety of the sidewalks by changing of beam section and prestressing the bolts.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.7
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• pp.489-495
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• 2017

An experimental study on supersonic jets produced by supersonic nozzles at low operating pressure ratio is conducted. In the present experiments, particle image velocimetry (PIV) was employed to quantitatively specify the jet flowfield, and a color Schlieren optical method was applied to observe the same jets qualitatively. Convergent-divergent nozzles were used to generate the jet flow with design Mach numbers of 1.5 and 1.8. Nozzle pressure ratios (NPRs) were varied from 4 to 7. A good comparison of the jet size from the Schlieren images with the theoretical values is obtained. The obtained images clearly showed the major features of the under-expanded jet and over-expanded jet.

• Journal of the Korean Home Economics Association
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• v.19 no.3
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• pp.21-32
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• 1981

Clothing must have the individual beauty and the function that one can do one's body movement freely. therefore, from the human engineering view point, the exact measurement of the human body and the analysis of it's results must be applied to clothing because the arm works most. In this study, the skin surface of arm was investigated by shell made of Alginate of each movement. And by sometic method the rate of expansion and contraction of each section, inter-relation among the bust girth, axillary arm girth and scye girth and between the shoulder length right and the under axilla waist length were calculate4d. With these results, cap height, breadth of a sleeve and arm hole girth of existing sleeve pattern have been compared and analysed. The results are as follows; 1) According to the developmental figures of shell, the whole area change was small but that of shape was remarkable in M 4, 9, 13. The change of the Block 1 was particular. 2) Over arm length was contracted in all movements except M6 and under arm length expanded. The changes of sections a, b, c are large, while those of sections d, e are small. 3) In terms of latitudes, change of fore-arm region was small. The rate of scye girth varied from 14.3% of M13 to-5.6% of M2. The breadth of a sleeve expanded in all movements, and especially the front region expanded more than the back. 4) The relation between the shoulder length right and under axilla waist length, in all occasions, was contracted mutually, and one contracted, the other expanded. Therefore, in clothing construction when we consider the function of the arm it is better to widen the arm hole and the breadth of a sleeve at the same time than no widen the shoulder length by lowering the upper part of the upper side seam line.

• Composites Research
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• v.29 no.3
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• pp.91-97
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• 2016

In this paper, impulse-momentum theory was coupled to a constitutive equation both for implementing quasi-static and impact characteristics of EPP (Expanded polypropylene). Also, parameters which have physical meanings were expressed as functions of relative density. Simultaneous nonlinear Newton-Raphson method was applied to find the proper values for parameters in the constitutive equation along with quasi-static test data. Results from the impulse-momentum theory coupled constitutive equation showed good agreement with experimental data and the potential to be applied to different material type polymeric foam.

• Archives of Plastic Surgery
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• v.36 no.4
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• pp.365-371
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• 2009

Purpose: Good color match holds a key position in facial reconstruction for good aesthetic result. To correct the wide facial soft tissue defect were usually used the tissue expanded cheek flap, deltopectoral flap or radial forearm free flap. This study is aimed to analyse the color difference after flap surgery by using chromameter. Method: From August 1995 to December 2006, 30 patients underwent flap operations were chosen randomly and evaluated color differences between flap site and adjacent skin. Reconstructive procedures included tissue expanded cheek flap(n = 10), deltopectoral flap(n = 10), and radial forearm free flap(n = 10). The measured sites were flap center within a radius of 1 ㎝ and four points of adjacent skin along the flap margin. The color was quantified in a three dimensional coordinate system $L^*$ (brightness), $a^*$ (redness), $b^*$ (yellowness). Results: There was no significant color difference between the pedicled flaps(tissue expanded cheek flap and deltopectoral flap) and adjacent skin area. On the other hand, color values of the radial forearm free flap were statistically different from those of adjacent skin area. Total color difference(${\Delta}E$) of tissue expanded cheek flap and deltopectoral flap were $7.45{\pm}5.78$ versus $9.41{\pm}7.09$, and that of radial forearm free flap was $11.74{\pm}3.85$. They suggest that pedicled flaps have a potential of better color match than radial forearm free flap. Conclusion: Thus, better esthetic result and satisfaction is more likely to be expected in pedicled flaps as long as it could be applied comparing radial forearm free flap.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.1
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• pp.76-83
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• 2000

This study was carried out to predict blending ratio of cut tobacco(CT), expanded stem(ES), and expanded cut tobacco(ECT) in cigarettes. CT, ES, and ECT samples from A brand were, ground and blended with reference to A blending ratio, and scanned by near infrared spectroscopy(NIRSystem Co., Model 6500). Calibration equations were developed and then determined blending ratio by NIRS. The standard error of calibration(SEC) and performance(SEP) of C factory samples between NIRS and known blending ratio were 0.97%, 1.93% for CT, 0.50%, 1.12 % for ES and 0.68%, 1.10% for ECT, respectively. The SEP of CT, ES and ECT of Band D factory samples determined by C factory calibration equation were more inaccurate than those of C factory samples determined by C factory calibration equations. These results were caused by the difference of CT, ES and ECT spectra followed by each factory. The SEP of CT, ES and ECT of Band D factories determined by calibration equations derived from each factory samples were more accurate than those of determined by calibration equation derived from C factory samples. Each factory SEP of CT, ES and ECT determined by calibration equation derived from all calibration samples(B+C+D factory) was similar to that determined by calibration equation derived from each factory samples. To improve the analytical inaccuracy caused by spectra difference, we need to apply a specific calibration equation for each factory sample. Data in development of specific calibrations between sample and NIRS spectra might supply a method for rapid determination of blending ratio of CT, ES, and ECT.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.604-605
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• 2017

The present work aims at visualization of the supersonic air jet flows discharged from C-D nozzles. In the present experiments, Prticle Image Velocimetry (PIV) was employed to specify the jet flow field quantitatively, and a color Schlieren optical method was applied to observe the same jets qualitatively. The $0.5{\mu}s$ duration of spark light source was used for Schlieren and it can be controled as $0.5{\mu}s$, $1{\mu}s$, $2{\mu}s$ and focusing mode. The convergent-divergent nozzles were used to generate the jet flow with the design Mach number of 2.0, 2.2. Nozzle pressure ratios (NPRs) were varied from 5 to 8. A good comparison of the jet size and shock location from the Schlieren images with the PIV quantitative values is obtained. The obtained images clearly showed the major features of the under-expanded jet, over-expanded jet, sound wave, turbulent eddies and so on.

• Geomechanics and Engineering
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• v.23 no.4
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• pp.313-325
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• 2020

Slope displacement and factor of safety (FOS) of a slope are two aspects that reflect the stability of a slope. However, the traditional limit equilibrium (LE) methods only give the result of the slope FOS and cannot be used to solve for the slope displacement. Therefore, developing a LE method to obtain the results of the slope FOS and slope displacement has significance for engineering applications. Based on a force-displacement coupled mode, this work expands the LE Morgenstern-Price (M-P) method. Except for the mechanical equilibrium conditions of a sliding body adopted in the traditional M-P method, the present method introduces a nonlinear model of the shear stress and shear displacement. Moreover, the energy equation satisfied by a sliding body under a small slope displacement is also applied. Therefore, the double solutions of the slope FOS and horizontal slope displacement are established. Furthermore, the flow chart for the expanded LE M-P method is given. By comparisons and analyses of slope examples, the present method has close results with previous research and numerical simulation methods, thus verifying the feasibility of the present method. Thereafter, from the parametric analysis, the following conclusions are obtained: (1) the shear displacement parameters of the soil affect the horizontal slope displacement but have little effect on the slope FOS; and (2) the curves of the horizontal slope displacement vs. the minimum slope FOS could be fitted by a hyperbolic model, which would be beneficial to obtain the horizontal slope displacement for the slope in the critical state.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1765-1772
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• 2002

Three experiments were conducted to determine the feed processing method best suited for early and conventionallyweaned pigs, and to investigate the effects of different extrusion temperatures on ileal digestibility of amino acids in diets containing different protein sources. In exp.1, a total of 108 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 24 d of age and 7.60 kg average body weight) were alloted on the basis of sex, weight and ancestry to three treatments in a randomized complete block design. Feed processing methods used were mash (M), simple pellet (SP), and expanded pellet (EP). In exp. 2, a total of 96 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 14 d of age) were allotted on the basis of sex, weight, and ancestry to three treatments in a randomized complete block design. Diets were mash (M), expanded pellet (EP), and expanded pellet crumble (EPC). In exp. 3, a study was designed to investigate the effect of different extrusion temperatures (100, 120, and $140^{\circ}C$) over the control (untreated) on the ileal digestibility of amino acids in diets containing protein sources such as spray-dried plasma protein (SDPP), whey protein concentrate (WPC), and fish meal (FM). Results in exp.1 showed that ADG, ADFI and the F/G ratio of pigs fed the SP diet were improved (p<0.05) compared with those fed the M or the EP diets, but the digestibility of nutrients was not different (p>0.05) among the treatments. In exp. 2, pigs fed expanded pellet treatments (EP or EPC) had a significantly improved (p<0.05) F/G ratio compared to the pigs fed the M diet which was primarily attributed to the significant reduction (p<0.05) in ADFI, but the overall growth rate of pigs fed expanded pellet diets was not improved. In exp. 3, there was a significant interaction effect (p<0.05) between the extrusion temperature and protein source on the ileal digestibility of amino acids. With an extrusion temperature of $100^{\circ}C$, the ileal digestibility of Lys, Val, Gly and Ser was significantly lower in the diet containing WPC compared to the diet containing SDPP. Increasing the temperature to $120^{\circ}C$ led to significant differences (p<0.05) in the digestibility of Thr and Tyr between diets containing WPC and SDPP. Regardless of extrusion temperatures, the weaned pigs' diet containing either SDPP or FM had significantly higher Lys, Phe, Thr, Val, and Gly digestibility relative to the WPC diet. Results of the present study suggest that simple pelleting of diets containing protein sources such as whey protein concentrate, spray-dried plasma protein and fish meal would be better than the extruded or expanded pellet diets. Extruder or expander processing of weaned pigs' feed could reduce palatability and ileal digestibility of several amino acids and therefore may be responsible for a negative growth response in weaned pigs.