• Journal of the Korea Concrete Institute
• /
• v.18 no.6 s.96
• /
• pp.811-817
• /
• 2006

The primary purpose of this study is to estimate the guaranteed strength and construction quality of the combined high flowing concrete which is used in the slurry wall of underground LNG storage tank. The required compressive strength of this type of concrete become generally known as a non economical value because it is applied the high addition factor for variation coefficients and low reduction factor under water concrete. Therefore, after estimation of the construction quality and guaranteed strength in actual site work, this study is to propose a suitable equation to calculate the required compressive strength in order to improve its difference. Application results in actual site work are shown as followings. The optimum nix design proportion is selected that has water-cement ratio 51%, sand-aggregate ratio 48.8%, and replacement ratio 42.6% of lime stone powder by cement weight. Test results of slump flow as construction quality give average 616~634mm. 500mm flowing time and air content are satisfied with specifications in the rage of 6.3 seconds and 4.0% respectively. Results of strength test by standard curing mold show that average compressive strength is 49.9MPa, standard deviation and variation coefficients are low as 1.66MPa and 3.36%. Also test results by cored cylinder show that average compressive strength is 66.4MPa, standard deviation and variation coefficients are low as 3.64MPa and 5.48%. The guaranteed strength ratio between standard curing mold and cored cylinder show 1.23 and 1.32 in the flanks. It is shown that applied addition factor for variation coefficients and reduction factor under water concrete to calculate the required compressive strength is proved very conservative. Therefore, based on these results, it is proposed new equation having variation coefficients 7%, addition factor 1.13 and reduction factor 0.98 under water connote.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.4
• /
• pp.363-371
• /
• 2023

To construct a ship, blocks of various sizes must be moved and erected . In this process, lugs are used such that they match the block fastening method and various functions suitable for the characteristics of each shipyard facility. The sizes and shapes of the lugs vary depending on the weight and shape of the block structures. The structure is reinforced by welding the doubling pads to compensate for insufficient rigidity around the holes where the shackle is fastened. As for the method of designing lugs according to lifting loading conditions, a simple calculation based on the beam theory and structural analysis using numerical modeling are performed. In the case of the analytical method, a standardized evaluation method must be established because results may differ depending on the type of element and modeling method. The application of this ambiguous methodology may cause serious safety problems during the process of moving and turning-over blocks. In this study , the effects of various parameters are compared and analyzed through numerical structural analysis to determine the modeling conditions and evaluation method that can evaluate the actual structural response of the lug. The modeling technique that represents the plate part and weld bead around the lug hole provides the most realistic behavior results. The modeling results with the same conditions as those of the actual lug where only the weld bead is connected to the main body of the lug, showed a lower ulimated strength compared with the results obtained by applying the MPC load. The two-dimensional shell element is applied to reduce the modeling and analysis time, and a safety working load was verified to be predicted by reducing the thickness of the doubling pad by 85%. The results of the effects of various parameters reviewed in the study are expected to be used as good reference data for the lug design and safe working load prediction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.7
• /
• pp.4184-4190
• /
• 2014

The present paper examined the stress and ADL (activities of daily living) index in relation to the characteristics of the elderly in nursing homes. For this study, questionnaires were given to 110 seniors in the N-district of Seoul, and S-myeon, Hoengseong-gun, Gangwon Province from May 1 to September 30, 2013. For data analysis, t-test, correlation analysis, and multiple regression analysis were performed using the SPSSWIN18.0 program. The analysis of actual proof was made at a significance level of 5 percent. The findings from the analyses were as follows: first, the relocation syndrome into nursing homes has a positive correlation with the stress of deficient family visits in the category of daily stresses; second, depression has a positive correlation with the stresses of deficient private time and space and deficient family visits in the category of daily stresses; third, weight control has a positive correlation only with the stress of deficient private time and space in the category of daily stresses, whereas a nutrition deficiency has positive correlation with the stress of deficient family visits in the category of daily stresses. These findings may serve as ground source data for establishing policies regarding the stresses in relation to the characteristics and ADL index of the elderly in nursing homes.

• Asian-Australasian Journal of Animal Sciences
• /
• v.31 no.5
• /
• pp.763-772
• /
• 2018

Objective: Swine manure in Korea is separated into solid and liquid phases which are composted separately and then applied on land. The nutrient accumulation in soil has been a big issue in Korea but the basic investigation about nutrient input on arable land has not been achieved in detail. Within the nutrient production from livestock at the national level, most values are calculated by multiplication of the number of animals with the excreta unit per animal. However, the actual amount of nutrients from swine manure may be totally different with the nutrients applied to soil since livestock breeding systems are not the same with each country. Methods: This study investigated 15 farms producing solid compost and 14 farms producing liquid compost. Composting for solid phase used the Turning+Aeration (TA) or Turning (T) only methods, while liquid phase aeration composting was achieved by continuous (CA), intermittent (IA), or no aeration (NA). Three scenarios were constructed for investigating solid compost: i) farm investigation, ii) reference study, and iii) theoretical P changes (${\Delta}P=0$), whereas an experiment for water evaporation was conducted for analyzing liquid compost. Results: In farm investigation, weight loss rates of 62% and 63% were obtained for TA and T, respectively, while evaporation rates for liquid compost were 8.75, 7.27, and $5.14L/m^2{\cdot}d$ for CA, IA, and NA, respectively. Farm investigation provided with the combined nutrient load (solid+liquid) of VS, N, and P of 117.6, 7.2, and $2.7kg/head{\cdot}yr$. Nutrient load calculated from farm investigation is about two times higher than the calculated with reference documents. Conclusion: The nutrient loading coefficients from one swine (solid+liquid) were (volatile solids, 0.79; nitrogen, 0.53; phosphorus, 0.71) with nutrient loss of 21%, 47%, and 29%, respectively. The nutrient count from livestock manure using the excretion unit has probably been overestimated without consideration of the nutrient loss.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.6
• /
• pp.103-112
• /
• 2020

In this study, based on actual project implementation cases, task management plans for construction management related green building certification were derived in major stages. Accordingly, the importance from details of construction management tasks for the operation and management process of the schematic design phase, design development phase, and construction document phase, focusing on G-SEED certification, was analyzed. In addition, major items were derived based on the weight of additional construction costs and acquisition scores through previous research cases on the analysis of construction costs for G-SEED certification, and the importance from details of construction management tasks on the major items of G-SEED certification was analyzed. As a result, the review and confirmation of the elements of reflection related to G-SEED in the schematic design phase, the adequacy of design documents and the connectivity of design phase in the design development phase were important. And the review and confirmation of the items directly related to the construction phase in the construction document phase were important.

• Journal of Korean Academy of Nursing
• /
• v.25 no.2
• /
• pp.351-361
• /
• 1995

The main purpose of the study is to identify critical risk factors for development of a family assessment tool to screen high risk family. This study used a conceptual framework of family diagnosis developed by Eui-sook Kim's (1993) and analyzed risk factors to identify the high risk family. As employing a explorative and methodological study design, this study has four stages. 1. In the first stage, 34 family risk factors were identified by doing intensive literature review on conceptual framework of family diagnoses. 2. In the second stage, above risk factors were tested for content validity by consultation with 29 persons in community health nursing, nursing education, family theory, and social work. 3. In the third stage, existing survey data was used for actual application of the identified risk factors. The survey data used for this purpose was previously collected for the community diagnosis in a region of Seoul. At the final stage, through the comparison between high risk and low risk families, initially identified 34 risk factors decreased to 25 risk factors. Among 34 risk factors, six factors did not agree with content of questionnaries sand two factors were not significant in differentiating the high risk family Also, two risk factors showed high correlation between themselves, so only one of those two factors was chosen. As a result, twenty-five risk factors chosen to identify the high risk family are following ; 1. A single parent family due to divorce or death of a partner, or unweded single mother 2. A family with an unrelated household members 3. A family with a working mother with a young child 4. A family with no regular income 5. A family with no rule in family or too strict rules 6. A family with little or no support from other lam-ily members 7. A family with little or no support from friends or relatives 8. A family with little or no time to share with each other 9. A family with family history of hypertension, diabetus, cancer 10. A family with a sick person 11. A family with a mentally ill person 12. A family with a disabled person 13. A family with an alcoholic person 14. A family with a excessive smoker who smokes more than 1 pack / day 15. A family with too much salt intake in their diet. 16. A family with inappropriate management skills for family health 17. A family with high utilization of drug store than hospital to solve the health problems of the family 18. A family with disharmony between husband and wife 19. A family with conflicts among the family members 20. A family with unequal division of labor among family members 21. An authoritative family structure 22. A socially isolated family 23. The location of house is not residential area 24. A family with high risk of accidents 25. The drinking water and sewage systems are not hygienic. The main implication of the results of this study is clinical use. The high risk factors can be used to identify the high risk family effectively and efficiently. The use of high risk factors woule contribute to develop a conceptual framework of family diagnosis in Korea and the list of risk factors need to be revised continuously. Further researches are needed to develop an index of weight of each risk factor and to validate the risk factors.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.4
• /
• pp.75-81
• /
• 2012

In case of crushing rock to produce materials for lean concrete subbase layer in concrete pavement, natural sand is used for the gradation adjustment of aggregates, and the percentage of natural sand used is 30%~40% of the weight ratio of aggregate mix. The supply of natural sand that is used in lean concrete as a fine aggregate is getting harder due to the current of exhaustion of source, and the cost for the purchase of natural sand is included in the cost of roadway construction. This study, therefore, was conducted in order to resolve the exhaustion of materials and economize in construction expenditure by the application of screenings, which is by-product of crushing rock in quarry, as an alternative to natural sand. As a result of a comparative analysis on the application of screenings and natural sand with typical types of rock that is produced in domestic, which was conducted in the first year, It is found out that the use of screenings as a fine aggregate showed better unconfined compression strength. Verification of actual application of screenings was conducted in the second year, after test construction and follow-up investigation. The compressive strength, compaction density, settlement of screenings applied case was higher than that of natural sand. Thus, it is expected that application of screenings to construction in field will contribute to the cost saving, material recycling and the protection of environment.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.4
• /
• pp.359-367
• /
• 2014

Drought index can be used to implement an early warning system for drought and to operate a drought monitoring service. In this study, an approach was examined to determine agricultural drought index (ADI) at high spatial resolution, e.g., 270 m. The value of ADI was calculated based on soil water balance between supply and demand of water. Water supply is calculated by the cumulative effective precipitation with the application of the weight to the precipitation from two months ago. Water demand is derived from the actual evapotranspiration, which was calculated applying a crop coefficient to the reference evapotranspiration. The amount of surface runoff on a given soil type was also used to calculate soil residual moisture. Presence of drought was determined based on the probability distribution in the given area. In order to assess the reliability of this index, the amount of residual moisture, which represents severity of drought, was compared with measurements of soil moisture at three experimental between July 2012 and December 2013. As a result, the ADI had greater correlation with measured soil moisture compared with the standardized precipitation index, which suggested that the ADI would be useful for drought warning services.

• Journal of Korea Port Economic Association
• /
• v.33 no.3
• /
• pp.35-52
• /
• 2017

Interest and demand in heavy cargo logistics is increasing and becoming more diverse as economic scales have expanded and manufacturing activity has increased. Although cargo moves via maritime and/or land transportation, there is currently insufficient research on the actual condition of heavy cargo logistics. The purpose of this study is to carry out an in-depth analysis of heavy cargo laws, systems, logistics patterns, and current transportation status. By proposing measures to solve existing problems, this study aims to make an important and ongoing contribution to the scarcely studied field of heavy cargo logistics. The result of regression analysis on the main seven factors show that transportation frequency and law/system structure have a positive effect on working conditions. Furthermore, the result of correlation analysis on the main seven factors show that the cargo weight variable is highly positively correlated with cargo size. Also, the working conditions variable is highly positively correlated with the law/system structure. Detailed proposal measures to solve existing problems are summarized as follows. First, it is necessary to establish a clear concept of heavy cargo as numerous existing definitions differ. Second, laws and provisions relating to maritime and land transportation of heavy cargo need to be established and consolidated as current applicable legislation is insufficient. Third, the classification system for heavy cargo transportation needs improvement. Fourth, it is necessary to improve transportation performance statistics and the aggregate criteria system. Finally, the management system of heavy cargo also needs improvement.

• Korean Journal of Environment and Ecology
• /
• v.30 no.6
• /
• pp.1067-1072
• /
• 2016

In this study, we determined the ecological characteristics of Strix aluco, which is designated as an endangered category II species. Towards this, we identified the actual home range of Strix aluco that breed in Korea, and collected the data necessary for protecting, preserving and managing owl populations. This study was conducted from April 14 to May 20 of 2016 during the breeding season of Strix aluco as part of the 4th National Ecosystem Survey and in accordance with the Natural Environment Conservation Act. We captured and subsequently released a female owl with a total length of 423.5mm and a weight of 550g in Kyungbuk area, succeeded in tracking it for the first time in Korea and secured 6 points of direct observation and satellite tracking observation. The distance from the nest to the farthest point was 93m. As a result of the analysis of habitat points within a100m-radius during breeding period, it was established that their habitat consists of 34.2% of non-irrigated land, 30.6% of mixed forest land, 10.5% of orchard, and 9.4% of natural grassland. These findings are consistent with the previous estimate of home range studies. Further research based on follow-up studies on males or other individuals is required to develop a stronger basis for protection and conservation of endangered wildlife class II owls.