• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.4
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• pp.348-353
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• 2008

Oxygen isotope has not been used actively in water mass studies because of difficulties on the analysis though it has advantages as a water mass tracer. The most popular method to analysis the oxygen isotope ratio in water samples is equilibration method: isotopic equilibrium of water with $CO_2$ at constant temperature. The precision of oxygen isotope analysis using commercial automatic $H_2O/CO_2$ equilibrator is ${\pm}0.1%o$. This value is not sufficient for studies in open ocean. The object of this study is to improve the analytical precision enough to apply open ocean studies by modification of the instrument. When sample gas is transferred by the pressure difference, the fractionation which is preferential transportation of light isotope can be occurred since the long transportation path between the equilibrator and mass spectrometer. And the The biggest source of error during the analysis is long distance and large volume of the pathway of sample gas between. Therefore, liquid nitrogen trap and high vacuum system are introduced to the system. The precisions of 14 time analysis of same seawater sample are ${\pm}0.081%o$ and ${\pm}0.021%o$ by built-in system and by modified system in this study, respectively.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.30-35
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• 2011

To clarify the hydraulic and thermal characteristics of ice slurry which made from 6.5% ethylene glycol-water solution flow in the double tube and plate type heat exchanger, experimental studies were performed. The mass flux and ice fraction of ice slurry were varied from 800 to 3500 kg/$m^2s$(or 7 to 17 kg/min) and from 0 to 25%, respectively. Through the experiment, it was found that the measured pressure drop and heat transfer rate increase with the mass flux and ice fraction; however the effect of ice fraction appears not to be significant at high mass flux region. At the region of low mass flux, a sharp increase in the pressure drop and heat transfer rate were observed depends on mass flux.

• Journal of agricultural medicine and community health
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• v.1 no.1
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• pp.22-28
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• 1976

It has been well known that indiscriminative use of pesticides contaminates water resources and soil to break down the balance of natural ecosystem and brings acute when spray. In this country, 62,602 tons of pesticides were used in 1974 for agricultural purpose figuring 28.0 kg per hectare which showed 20% increasement every year since 1970. It is almost impossible to figure out incidence and mortality of acute pesticide poisoning exactly. However, a survey in 1974 reported that 33.5% of male and 32.7% of female who sprayed certain pesticides complained of several symptoms seemed to be due to acute pesticide poisoning. It also mentioned that the main cause inducing poisoning supposedly was dusting without protective armamation such as masks, booths, gloves and others in more than 60% of above cases. Pesticide poisoning through contamination of food or direct inhalation and contact. With the reason, the followings can be recommended to minimize or prevent pesticide hazards. 1. Strict legal control 2. Systematic education on the safe handling way of pesticides for the people who are to use them. 3. Remarkable warning at transportation and stocking of pesticides. 4. Obligatory attachment of explanation on the package about effect, safe handling method, and. emergency care at acute pesticide poisoning concerned.

• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.336-350
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• 2013

This paper proposes a mathematical modeling-based approach for assessing disaster effects and selecting suitable mitigation alternatives to provide humanitarian relief (HR) supplies, shelter, rescue services, and long-term services after a disaster event. Mitigation steps, such as arrangement of shelter and providing HR items (food, water, medicine, etc.) are the immediate requirements after a disaster. Since governments and non-governmental organizations (NGOs) providing humanitarian aid need to know the requirements of relief supplies and resources for collecting relief supplies, organizing and initiating mitigation steps, a quick assessment of the requirements is the precondition for effective disaster management. Based on satellite images from weather forecasting channels, an area/dimension of the disaster-affected zones and the extent of the overall damage may often be obtained. The proposed approach then estimates the requirements for HR supplies, supporting resources, and rescue services using the census and other government data. It then determines reliable transportation routes, optimum collection and distribution centers, alternatives for resource support, rescue services, and long-term help needed for the disaster-affected zones. A numerical example illustrates the applicability of the model in disaster mitigation planning.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.153-153
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• 2010

The world is moving towards a post-carbon society and needs clean and renewable energy for sustainable development. There are many methodological approaches which are helping this shift based on analyzed data about energy resources and which focus on limited types of energy including liquid fossil, solid fossil, gaseous fossil, and biomass (e.g. IPCC Guidelines, ISO 14064-1, WRI Protocol, etc.). We should also consider environmental impact (e.g. greenhouse gas emissions, water use, etc.) and the economic cost of the renewable energy to make a better decision. Recently, researchers have addressed the environmental impact of new technologies which include photovoltaics, wind turbines, hydroelectric power, and biofuel. In this work, we analyze the environmental impact with a carbon emission factor to present a correlation between $CO_2$ emission and the cost of energy resources standardized by the energy output. In addition, we reviewed Life Cycle Assessment (LCA) as another methodology. Researchers who are studying energy systems have ignored the impacts of entire energy systems, e.g. the extraction and processing of fossil fuels. In power sector, the assessment should include extraction, processing, and transportation of fuels, building of power plants, production of electricity, and waste disposal. Therefore LCA could be more suitable tool for energy cost and environmental impact estimation.

• Geomechanics and Engineering
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• v.22 no.2
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• pp.153-163
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• 2020

Laboratory experiments were conducted with two different soil conditions to investigate rainfall infiltration characteristics. The soil layer materials that were tested were weathered granite soil and weathered gneiss soil. Artificial rainfall of 80 mm/hr was reproduced through the use of a rainfall device, and the volumetric water content and matric suction were measured. In the case of the granite soil, the saturation velocity and the moving direction of the wetting front were fast and upward, respectively, whereas in the case of the weathered gneiss soil, the velocity and direction were slow and downward, respectively. Rainfall penetrated and saturated from the bottom to the top as the hydraulic conductivity of the granite soil was higher than the infiltration capacity of the artificial rainfall. In contrast, as the hydraulic conductivity of the gneiss soil was lower than the infiltration capacity of the rainfall, ponding occurred on the surface: part of the rainfall first infiltrated, with the remaining rainfall subsequently flowing out. The unsaturated hydraulic conductivity function of weathered soils was determined and analyzed with matric suction and the effective degree of saturation.

• Advances in concrete construction
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• v.9 no.3
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• pp.327-335
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• 2020

Concrete pipes are considered important structures playing integral role in spread of cities besides transportation of gas as well as oil for far distances. Further, concrete structures under seismic load, show behaviors which require to be investigated and improved. Therefore, present research concerns dynamic stress and strain alongside deflection assessment of a concrete pipe carrying water-based nanofluid subjected to seismic loads. This pipe placed in soil is modeled through spring as well as damper. Navier-Stokes equation is utilized in order to gain force created via fluid and, moreover, mixture rule is applied to regard the influences related to nanoparticles. So as to model the structure mathematically, higher order refined shear deformation theory is exercised and with respect to energy method, the motion equations are obtained eventually. The obtained motion equations will be solved with Galerkin and Newmark procedures and consequently, the concrete pipe's dynamic stress, strain as well as deflection can be evaluated. Further, various parameters containing volume percent of nanoparticles, internal fluid, soil foundation, damping and length to diameter proportion of the pipe and their influences upon dynamic stress and strain besides displacement will be analyzed. According to conclusions, increase in volume percent of nanoparticles leads to decrease in dynamic stress, strain as well as displacement of structure.

• Journal of the Society of Disaster Information
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• v.13 no.1
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• pp.6-14
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• 2017

The opportunity provided for design method and strategy of sustainable campus on the waterfront, is the purpose of this paper. Waterfront campus is an important issue as it seeks to revive the sustainability and to renew the facilities. This paper reviews an assessment of its success for waterfront campus in 10 principles such as waterfront, water and safety, climate & energy, green building and transportation, green labs and recycling, health and food, social economic sustainability, fund, human, smart, also concludes with the establishment of space making for the waterfront campus for future educational facilities on the waterfront; implementation of waterfront campus maserplan; building sustainable campus in adaptation to climate change; creative and resilient cooperation.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.4 s.142
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• pp.322-329
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• 2005

Viscous flows behind transom stern are analyzed based on CFD simulation results. Stern wave pattern is often complicated due to the abrupt change of stern surface curvature and flow separation at transom. When a ship advances at high speed, whole transom stern is exposed out of water, resulting in the so-called 'dry transom'. However, in the moderate speed regime, stern wave development in conjunction of flow separation makes unstable wavy surface partially covering transom surface, i.e., the so-called 'wetted transom'. Transom wave formation is usually affecting the resistance characteristics of a ship, since the pressure contribution on transom surface as well as the wave-making resistance is changed. Flow modeling for 'wetted transom' is difficult, while the 'dry transom modeling' is often applied for the high-speed vessels. In the present study CFD results from the RANS equation solver using a finite volume method with level-set treatment are utilized to assess the topology of transom flow pattern for a destroyer model (DTMB5415) and a container ship (KCS). It is found that transom flow patterns are quite different for the two ships, in conformity to the shape of submerged transom. Furthermore, the existence of free surface seems to after the flow topology in case of KCS.

• International Journal of Concrete Structures and Materials
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• v.4 no.1
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• pp.9-15
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• 2010

Silica fume is a common addition to high performance concrete mix designs. The use of silica fume in concrete leads to increased water demand. For this reason, Florida Department of Transportation (FDOT) allows only a 72-hour continuous moist cure process for concrete containing silica fume. Accelerated curing has been shown to be effective in producing high-performance characteristics at early ages in silica-fume concrete. However, the heat greatly increases the moisture loss from exposed surfaces, which may cause shrinkage problems. An experimental study was undertaken to determine the feasibility of steam curing of FDOT concrete with silica fume in order to reduce precast turnaround time. Various steam curing durations were utilized with full-scale precast prestressed pile specimens. The concrete compressive strength and shrinkage were determined for various durations of steam curing. Results indicate that steam cured silica fume concrete met all FDOT requirements for the 12, 18 and 24 hours of curing periods. No shrinkage cracking was observed in any samples up to one year age. It was recommended that FDOT allow the 12 hour steam curing for concrete with silica fume.