• 한국식생활문화학회지
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• 제19권3호
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• pp.273-284
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• 2004

This study is on the changing pattern of fish-and-shellfish uses during the last two thirds of Chosun period on the premise that they are influenced by development of fishing technology. With a literary approach, this paper researches how fish-and-shellfish production and consumption pattern changed, especially in relation to technological development of fisheries. First, we examine into the changes of fishery production. And next, we analyze the kind and cooking method of fish-and-shellfish in [Eum-sik-di-mi-bang](1670) and [Gyu-hap-chong-seo](1815). The analysis of two books revealed that there were significant differences in fish-and-shellfish uses. Because the two books were written with a gap of 145 years and the development of fishing technology and remarkable changes of fishery production affected on the fish-and-shellfish uses. Due to primitive fishing tools and skills, fresh-water and reverse-river-fish and shellfish had been caught in substantial amount until the middle ages of Chosun period. As a result, the availability of seafood were limited extremely even in the upper classes. These situations are evidenced by the analysis of [Eum-sik-di-mi-bang]. Only 12 kinds of fish-and-shellfish are described in [Eum-sik-di-mi-bang]. Most of the sesfoods is mollusc which is easy to catch. As for the salt-water fish, dried cod and dried herring were mentioned. Mullet, the reverse-water-fish, is used most frequently. Only one kind of 'Hoe', which needs extreme freshness, is described. This means that the use of fresh fish-and-shellfish was very limited to some kinds which could be caught near the village. As the netting fishery began to be developed in the 18th century, the production of some salt-water fishes, such as anchovy, shrimp, yellow corvina, pollack, and herring, had increased remarkably to make marine resources more available. Small fish, such as anchovy and shrimp were preserved as 'Jeot-gal' and sold nationwide. Therefore, 'Jeot-gal' and seafood could be used in Kimchi around this time and had a deep influence on the change of Kimchi in taste and nutrition. In [Gyu-hap-chong-seo], 33 kinds of fish-and-shellfish are described. Including cod and herring, 17 kinds of sea water fish and mollusc are mentioned. Some of these are consumed in fresh state, neither as dried nor as salted. Because the merchants promoted the transport of seafoods to other regions according to the growth of commercial economy. As a result the diet of the people could be enriched by the various seafoods.

• 한국지하수토양환경학회지:지하수토양환경
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• 제9권2호
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• pp.54-63
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• 2004

서울의 지하수는 토양법이나 지하수법이 제정되기 전에 이미 오염물질의 토양 무단투기, 주유소나 유류의 지하저장 탱크 등이 들어서면서 오염에 노출되었으나 최근에 지하수에 관심이 많아지고 지하수 오염방지 계획에 따라 주기적이고 지역적인 검사가 이루어져 지하수 행정에 반명되고 있다. 서울시 소재 지하수 관정 1,352개소의 수질을 분석하여 먹는물중 적합은 52.6％,부적합은 47.4％로 나타났고 생활ㆍ농ㆍ공업용수로 적합은 91.9％인 8.1％가 부적합으로 나타났고 pH는 왜도와 첨도가 0.022와 -0.524인데 반하여 일반세균, 색도, 탁도, 암모니아성 질소, 질산성 질소, 철, 망간이 각각 11.641과 174.324, 8.501과 80.260, 5.675와 32.821, 가 19.507과 380.994, 가 3.323과 17.436, 10.544와 134.093, 5.979와 39.124로 나타났고, 지하수 먹는물 비상급수에서 설치년도, 심도 및 양수량은 수질의 적부에 영향을 미치지 않는 것으로 나타났고 관정 설치 해와 심도, 양수량은 각각 0.381, -0.169로 나타나 시간이 지날수록 지하수 관정의 굴착깊이는 깊어지고 양수량은 적어지는 것으로 나타났으며 심도와 질산성질소, 불소의 상관 계수는 -0.171, 0.332로 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.8-14
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• 2007

Water quality in Lake Rotorua, New Zealand, deteriorated since the 1960s because of excessive phytoplankton growths due principally to increasing nitrogen and phosphorus in the lake waters. Nutrient concentrations in eight of the nine major streams feeding Lake Rotorua have increased since 1965. The groundwater system has a key role in the hydrology of the Lake Rotorua catchment and the groundwater system is probably the control on the time delay between intensification of agricultural land use and response of surface water quality. All major, and many minor streams, in the catchment are fed by springs. Two lithological units are most important to groundwater flow in the Lake Rotorua catchment: Mamaku Ignimbrite, erupted in about 200,000 years ago and Huka Formation sediments which filled the caldera left by the Mamaku Ignimbrite eruption. Rainfall recharge to groundwater in the groundwater catchment of Lake Rotorua is estimated as approximately 17300 L/s. A calibrated steady-state groundwater flow model estimates that approximately 11100 L/s of this flow discharges into streams and then into the lake and the balance travels directly to Lake Rotorua as groundwater discharge through the lake bed. Land use has impacted on groundwater quality. Median Total Nitrogen (TN) values for shallow groundwater sites are highest for the dairy land use (5.965 mg/L). Median TN values are also relatively high for shallow sites with urban-road and cropping land uses (4.710 and 3.620 mg/L, respectively). Median TN values for all other uses are in the 1.4 to 1.5 mg/L range. Policy development for Lake Rotorua includes defining regional policies on water and land management and setting an action plan for Lake Rotorua restoration. Aims in the action plan include: definition of the current nutrient budget for Lake Rotorua, identification of nutrient reduction targets and identification of actions to achieve targets. Current actions to restore Lake Rotorua water quality include: treatment of Tikitere geothermal nitrogen inputs to Lake Rotorua, upgrade of Rotorua City sewage plant, new sewage reticulation and alum dosing in selected streams to remove phosphorus.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.237-241
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• 2003

The world's supply of water in all forms is enormous. However, only a tiny fraction of the planet's supply is available to us as fresh water, and that is distributed very unevenly. About 97％ of oater volume is found in the oceans and is too salty for drinking, growing crops, and most industrial uses except cooling. In addition water supply crises in already-water-short-regions will intensify because population and industrialization increase. Today, remote monitoring and control systems are becoming the cost-effective management tools for almost all water user groups, including irrigators, water districts, municipal water suppliers, and wildlife management groups. This paper represents a new approach in the water-gate control using radio communication. The proposed device is simple in structure and suitable for implementation of water-gate control through the transceiver by radio communication. It was confirmed that the developed device was very efficient to control level of water-gate and to prove the up and down motion of water-gate through the LCD displayer.

• 동력기계공학회지
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• 제15권2호
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• pp.25-30
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• 2011

A fresh water generation system is designed for converting brackish water or seawater into fresh water. In this paper fresh water generation by distillation process that evaporates feed water and subsequently condenses vapor as evaporation product to get fresh water was studied and city water was employed as feed water. The system uses the ejector to create a vacuum, under which liquid can be evaporated at lower temperature than it at normal or atmospheric condition, hence less energy consumption. The effect of various operating conditions i.e. temperature of feed water and different orifice diameters were studied experimentally to investigate the characteristic of the system. It was found that these parameters have significant effect in the performance of fresh water generation system with low pressure evaporation.

• 한국수자원학회논문집
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• 제40권11호
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• pp.869-876
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• 2007

본 연구는 수자원정책의 효율성 제고를 위한 판단 자료 제공을 목적으로 업종별 공업용수의 한계생산가치 및 공업용수의 가격탄력성을 추정하였다. 두 가지 형태의 생산함수를 설정하여 추정한 공업용수의 한계가치 및 가격탄력성을 추정 결과를 보면 공업용수의 한계가치는 산업별로 차이가 있으나 공업용수의 평균 가격에 비하여 매우 큰 것으로 추정되었으며 가격탄력성 추정결과는 가격 현실화 정책 효과가 있음을 보여주고 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1992년도 수공학연구발표회논문집
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• pp.325-328
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• 1992

The purpose of this research is to develop the technique of heavy metal removal from wastewater. The research is divided into two parts, one part uses complex precipitation and the other uses adsorption. In the first part of the study, humic acid is used as the complex agent, humic acid is a polyelectrolyte with a high complexation affinity. Lead, copper, zinc and cadmium were studied for their complex precipitation efficiencies. In the batch studies, humic acid was effective in removing 100% of the lead and 48.2% of the copper respectively from wastewater without anytreatment. The efficiency of cadmium and zinc, however, was very low. In the second part of the study, wastewater is introduced at the top of a silicagel adsorption column and then bottom effluent concentration is analyzed. The results of the analysis are used to draw a breakthrough curve.

• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.789-795
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• 2000

Free-surface flows with an arbitrary deformation, induced by a submerged hydrofoil, are simulated numerically, considering two-fluid flows of both water and air. The computation is performed by a finite volume method using unstructured meshes and an interface capturing scheme to determine the shape of the free surface. The method uses control volumes with an arbitrary number of faces and allows cell wise local mesh refinement. The integration in space is of second order, based on midpoint rule integration and linear interpolation. The method is fully implicit and uses quadratic interpolation in time through three time levels. The linear equations are solved by conjugate gradient type solvers, and the non-linearity of equations is accounted for through Picard iterations. The solution method is of pressure-correction type and solves sequentially the linearized momentum equations, the continuity equation, the conservation equation of one species, and the equations for two turbulence quantities. Finally, a comparison is quantitatively made at the same speed between the computation and experiment in which the grid sensitivity is numerically checked.

• 대한안전경영과학회지
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• 제3권1호
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• pp.117-125
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• 2001

Polyacetal resin is usually used to make molds, but it is difficult to achieve dimension accuracy during molding. Therefore it is usually necessary to cut the polyacetal resin after a molding process. Polyacetal resin is easily machining by standard machine tool. Acetal is also a thermal stable material which can be totted without coolant Another concern about the use of polyacetal resin is that it absorbs water easily, which also results in problems with dimension accuracy Therefore, in this study, the cutting resistance of water-absorbed polyacetal resin and its surface roughness after cutting in order to achieve the highest degree of accuracy in the cutting of polyacetal resin were investigated. Also, The Robust Design method uses a mathematical tool called orthogonal arrays to study a large number of decision variables with a small number of experiments. It also uses a new measure of quality, called signal-to-noise (S/N) ratio, to predict the quality from the customer's perspective. Thus, we have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/N ratio.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1676_1677
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• 2009

This paper uses the softstarter function of the inverter in the place of business where the flow control is possible, multi maneuver method as the application (with 1 inverter various pump maneuver/standstill which is soft) box the plan which prevents the small hand of the equipment which is caused by maneuver electric current presented.