• Advances in concrete construction
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• v.13 no.4
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• pp.281-289
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• 2022

3D printing cement-based materials (3DPCBM) is an innovative rapid prototyping technology for construction materials. This study is tested on the rheological behavior, printability and buildability of steel slag (SS) content based on the extrusion system of 3D printing. 0, 8 wt%, 16 wt%, 24 wt%, 32 wt% and 40 wt% SS was replaced cement, The test results revealed that the addition of SS would increase the fluidity of the printed paste, prolong the open time and setting time, reduce the plastic viscosity, dynamic yield stress and thixotropy, and is beneficial to improve the pumping and extrudability of 3DPCBM. With the increase of SS content, the static yield stress developed slowly with time which indicated that SS is harmful to the buildability of printing paste. The content of SS in 3DPCBM can reach up to 40% at most under the condition of satisfying rheological property and buildability, it provides a reference for the subsequent introduction of SS and other industrial solid waste into 3DPCBM by explored the influence law of SS on the rheological properties of 3DPCBM.

• Computers and Concrete
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• v.29 no.4
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• pp.209-217
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• 2022

In order to analyze the static and dynamic structural characteristics of the Obermeyer gate under overflow conditions, the force characteristics and vibration characteristics of the shield plate structure are studied based on the fluid-solid coupling theory. In this paper, the effects of the flow rate, airbag pressure and overflow water level on the structural performance of shield plate of air shield dam are explored through the method of controlling variables. The results show that the maximum equivalent stress and total deformation of the shield plate decrease first and then increase with the flow velocity. In addition, they are positively correlated with the airbag pressure. What's more, we find that the maximum equivalent stress of the shield plate decreases first and then increases with the overflow water level, and the total deformation of the shield plate decreases with the overflow water level. What's more importantly, the natural frequency of the shield structure of the Obermeyer gate is concentrated at 50 Hz and 100 Hz, so there is still the possibility of resonance. Once the resonance occurs, the free edge of the shield vibrates back and forth. This work may provide a theoretical reference for the safe and stable operation of the shield of the Obermeyer gate.

• Advances in nano research
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• v.12 no.3
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• pp.231-251
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• 2022

Dynamic behavior of temperature-dependent Reddy functionally graded (RFG) nanobeam subjected to thermomagnetic effects under the action of moving point load is carried out in the present work. Both symmetric and sigmoid functionally graded material distributions throughout the beam thickness are considered. To consider the significance of strain-stress gradient field, a material length scale parameter (LSP) is introduced while the significance of nonlocal elastic stress field is considered by introducing a nonlocal parameter (NP). In the framework of the nonlocal strain gradient theory (NSGT), the dynamic equations of motion are derived through Hamilton's principle. Navier approach is employed to solve the resulting equations of motion of the functionally graded (FG) nanoscale beam. The developed model is verified and compared with the available previous results and good agreement is observed. Effects of through-thickness variation of FG material distribution, beam aspect ratio, temperature variation, and magnetic field as well as the size-dependent parameters on the dynamic behavior are investigated. Introduction of the magnetic effect creates a hardening effect; therefore, higher values of natural frequencies are obtained while smaller values of the transverse deflections are produced. The obtained results can be useful as reference solutions for future dynamic and control analysis of FG nanobeams reinforced nanocomposites under thermomagnetic effects.

• Steel and Composite Structures
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• v.51 no.1
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• pp.53-61
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• 2024

Aluminum foams sandwich panel (AFSP) has been used in engineering field, where cyclic loading is used in most of the applications. In this paper, the fatigue life of AFSP prepared by the bonding method was investigated through a three-point bending test. The mathematical statistics method was used to analyze the influence of different plate thicknesses and core densities on the bending fatigue life. The macroscopic fatigue failure modes and damage mechanisms were observed by scanning electron microscopy (SEM). The results indicate that panel thickness and core layer density have a significant influence on the bending fatigue life of AFSP and their dispersion. The damage mechanism of fatigue failure to cells in aluminum foam is that the initial fatigue crack begins the cell wall, the thinnest position of the cell wall or the intersection of the cell wall and the cell ridge, where stress concentrations are more likely to occur. The fatigue failure of aluminum foam core usually starts from the semi-closed unit of the lower layer, and the fatigue crack propagates layer by layer along the direction of the maximum shear stress. The results can provide a reference for the practical engineering design and application of AFSP.

• Journal of Families and Better Life
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• v.31 no.5
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• pp.125-141
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• 2013

This research aims to integrate study results through a meta-analysis of previous studies on the variables related with social support for female marriage immigrants. Based on the results, this study established the foundation of an integrated social support system for female marriage immigrants which considers both the functional perspective and structural perspective of social support, and suggested plans for an efficient support system. All social support was positively associated with female marriage immigrants marriage life, child-rearing behavior and attitude, reduction of stress and depression and psychological stability. In relation to the effect size of each variable related with all social support, the marriage variable had the biggest relationship with it, followed by the parenting variable, the psychological variable and the stress variable in that order. With reference to the relationship with related variables according to the sub-domain of social support, from the structural perspective, spousale support showed a high relationship with the marriage variable and the stress variable. It was also especially, very highly related with the marriage variable. In addition, a married woman's family support and expert support had an intermediate relationship with the marriage variable, and the husband's family support and friend support had a low relationship with it. From the functional perspective, material support had a very high relationship with the marriage variable, whereas it had a low relationship with the stress variable and the psychological variable. Emotional support was also highly related with marriage variable, but showed an intermediate or low relationship with the psychological variable and the stress variable. On the other hand, informational support displayed an intermediate relationship with the stress variable and the psychological variable, and a high relationship with the marriage variable. Lastly, evaluative support had a high relationship with the marriage variable and the psychological variable. Based on these results, this study proposed plans for an integrated social support system as follows. First, education ought to be provided for the spouses, and support for marital adjustment should be offered. Second, there plans should be made for continuous bonding with the family of origin, and support should be given to address changes in awareness of the relationship with the husband's parents. Third, it is required to revitalize the local community and self-help groups, and provide the female marriage immigrants with opportunities to participate in social activities.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.380-389
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• 2012

In this study, Systematic review and meta-analysis using the correlation coefficients was carried out to integrate precedent studies on factors affecting domestic occupational therapists' job stress. It aims at providing basic information resources of preventing and reducing stress of occupational therapists and effective counter-measurement to improve quality of occupational therapy and to establish efficient human resource management policy. Systematic review and meta-analysis were performed on eight thesis proven relevant to selection criteria in order to figure out correlation coefficients value by total, and factors correlation coefficients value. Also homogeneity test and publication bias test was performed too. The total correlation coefficients value of occupational therapists was .30 which was statistically significant. As to job stress factors, the organization related factor showed the highest correlation of coefficiency, followed by factors other than the organization related, physical environment, job related factor and personal factor. This research result can be used as a reference to prevent and reduce job stress of occupational therapists and to develop an effective measurement scheme.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.658-666
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• 2018

The purpose of this study is to verify the effects of yoga and meditation-focused forest healing programs on profiles of mood states and stress reactions of adults. We tested 17 adults who agreed to participate in the experiments that were conducted for 2 nights and 3 days between September 8 to 10, 2017 in the healing forest located at Hongcheon-gun, Gangwon-do. The test used the simplified version of the inventory for the profile of mood states (K-POMS-B: Korean version of Profile of Mood States-Brief) and the stress response inventory as the measuring tools. For data analysis, we examined the differences in the profile of mood states and stress response of subjects before and after participation in the program through the paired T-tests with the SPSS 24.0 program. The analysis of the impact of the yoga and meditation-focused forest healing program on the profile of mood states of the test subjects showed the statistically significant reduction of the total score of the profile of mood states. Although the vigor among sub-level inventories increased, it was not statistically significant. But the tension, depression, anger, fatigue, and confusion showed a statistically significant reduction. The analysis of the impact of the yoga and meditation-focused forest healing program on the stress response of the test subjects showed a statistically significant reduction. Among sub-level inventories, the tension, somatization, anger, depression, fatigue, and frustration showed a statistically significant reduction, but the aggressiveness did not. It is expected that the results of this study can be utilized in the future as reference data for clarifying the effects of yoga and meditation-focused forest healing programs.

• Korean Journal of Culture and Social Issue
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• v.27 no.1
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• pp.35-49
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• 2021

The purpose of this study was examine the depression among Mongolians in South Korea. We also determined the effect of acculturative stress and social support on depression. In this study, total of 200 adults over age 18 completed the BDI-II of Mongolian Version, Acculturative stress scale for international student, The Multi-dimensional Scale of Perceived Social Support. Data were analyzed by using the factor analysis, correlation analysis, t-test, and hierarchical regression analysis. We used SPSS 22.0, AMOS 22.0. We found significant difference in mean scores between groups according to socio-demographic characteristics. The level of depression was high in over 3 years immigrants group (M = 8.41, SD = 9.6954), marriage immigrants group (M = 19.1, SD = 16.7649), and female groups (M = 7.61, SD = 9.2188) than compared to reference groups. Acculturative stress and social support of Mongolian immigrants had a significant impact on depression (β = .365, p <.001; β = .- 555, p <.001). There was a moderating effect of social support on the relationship between acculturative stress and depression (β = 1.080, p <.001). The limitations and implications of the study were discussed. We conclude that this study can be used to assess the depression and the mental health of Mongolians in South Korea.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.25-34
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• 2014

The aim of this study is to analyze the mechanical characteristics and settlement feature of the composite ground with structural form changes. The laboratory model test is a soil tanker to be contained with clay and grid form improved soil, which is conducted in total 9 case with the uniaxial compressive strength of improved soil and replacement ratio of improved soil. The numerical analysis for variation of stress distribution ratio with depth was performed in the same conditions which are the laboratory model test. As a result, stress distribution ratios in mid and high replacement ratio are increasing and settlement is decreasing, except low replacement ratio. This study is presented for form effect ratio and settlement reduction factor with change of structure form, which is able to be helpful in further research and reference for change of structural forms at composite ground.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.5
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• pp.631-636
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• 2013

This study was to evaluate the antioxidant properties of the leaf extracts of Diospyros lotus (DLE) on the chemical-induced free radical and rat red blood cell (RBC) oxidative damage in vitro. DLE were prepared by extracting with water. DLE showed the high antioxidant activities on the scavenging of 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)-induced radicals. An antioxidant activities of DLE was similar to the reference antioxidant butylated hydroxytoluene (BHT) and (${\pm}$)6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox). Reducing power of $1,000{\mu}g/mL$ DLE also was similar to the vitamin C. In RBC, oxidative hemolysis induced by the aqueous peroxyl radical generator (2,2'-Azobis (2-methylpropionamidine) dihydrochloride (AAPH)) were significantly suppressed by DLE in a dose-dependent manner. Furthermore, DLE prevented the depletion of cytosolic antioxidant glutathione in RBC damaged with AAPH. These results suggest that DLE may has value as natural product with its high quality antioxidant properties against oxidative stress.