• Title/Summary/Keyword: 규모효과

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Development of an Solid Separation System for Pig Slurry (돈 슬러리용 고형물 분리시스템 개발)

  • 김민균;김태일;최동윤;백광수;박진기;양창범;탁태영
    • Journal of Animal Environmental Science
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    • v.8 no.1
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    • pp.9-16
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    • 2002
  • This study was conducted to develope the new solid separating system which can be efficiently and economically removed the solid parts in high pollutants concentration of pig slurry. The pollutants concentration, BOD$_{5}$ , COD and SS of the slurry used in this study was 15,990($\pm$2,389)mg/l, 20,004($\pm$5,512)mg/l and 26,486($\pm$5,935)mg/l, respectively. After removal of solid part in slurry, the pollutants concentration, BOD$_{5}$, COD and SS was change into 5,617($\pm$690)mg/l, 5,553($\pm$633)mg/land 1,456($\pm$341)mg/l, respectively in the Fixed biological membrane tank. The reduction of the pollutants concentration of suspend liquid through membrane will be allowed to greatly improve the water purification by an Activated sludge method. This separating system consisted of a temporary storage, a circulating tank and a Fixed Biological membrane tank. A temporary storage which has a draining system of screw type and an aeration device played a tremendous role in draining the solid by filled an aeration of 0.3 l/min. A Fixed Biological membrane tank of which a styrofoam filled in a 2/3 volume as a Biological media was fixed by a stainless steel net (pore size : 0.5mm) to separate the liquid layer of influx in them. The separating system efficiency factors were the speed of screw motor, cycle number of slurries in a circulating tank and moisture contents of solid effluent through the screw path. Although the pollutants concentration was very variable in temporary storage, the final concentration of $BOD_5$ and SS, except COD of the suspended liquid in a Fixed biological membrane were not different regardless of cycle number of a circulating tank. Moisture contents of effluent from temporary storage was 73% under the speed 1 ppm of screw motor and 62% under the 1/4rpm of it.

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The Error Analysis of Scale Effect for Dam Submerged Area and the Surrounded Regions (댐 수몰 및 주변지역의 축척 규모에 따른 오차분석)

  • Lee, Geun-Sang;Choi, Yun-Woong;Hwang, Eui-Ho;Chae, Young-Gang
    • Spatial Information Research
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    • v.18 no.4
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    • pp.43-53
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    • 2010
  • A dam is effective in stable supply of water required in daily life and reduction of damage from floods. hut a lot of land or houses arc submerged due to the construction of a darn heavily affecting environment in surrounding areas. In order to improve and support daily life environment. surrounding a dam, many projects have been conducted. and the study has focused on analyzing bow to calculate error characteristics of scale effect for submerged area by using GIS spatial overlay. First, as a result of areal error in submerged area by scale based on a 1/3,000 digital topographic map, it was found that the 1/5,000 digital topographic map is 9.5 times, 9.0 times and 10.5 times more accurate than the 1/25,000 digital topographic map, respectively, in the total of areal error, standard error and areal error for submerged area. Second, as a result of analysis on areal error in areas surrounding a dam, it has been found that Jinan-eup in Jinan-gun registered the largest difference in area within 2km and 2~5km catchment area by recording 13.8 times and 20.6 times, respectively, in the 1/5,000 digital topographic map compared to the 1/25,000 digital topographic map. In addition, in areas out of catchment area within 2km, the area of occupation was very small, so there were no characteristics in error. The out of catchment area, Nami-myeon in Geumsan-gun recorded the largest errors of 31.8 times. Finally, it was found that the ratio of the total areal error in area surrounding a dam, standard error and the total areal error in the entire area using 1,5000 digital topographic map is 7.4 times, 11.8 times and 7.4 times more accurate than the 1/25,000 digital topographic map.

Geological Structure of Precambrian to Paleozoic metasedimentary rocks in the Janggunbng area, Korea -Crustal evolution and environmental geology of the central part of the North Sobaegsan Massif, Korea- (장군봉지역 선캠브리아대-고생대 변성퇴적암류의 지질구조 -북부 소백산육괴의 중앙부지역의 지각진화와 환경지질)

  • Gang, Ji Hun;Kim, Hyeong Sik;O, Se Bong
    • The Journal of the Petrological Society of Korea
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    • v.6 no.3
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    • pp.244-244
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    • 1997
  • The Janggunbong area(this study area) at the central-south part in the North Sobaegsan Massif, Korea, consists mainly of Precambrian(Wonnam and Yulri Formations)-Paleozoic [Joseon Supergroup(Jangsan Quarzite, Dueumri Formation and Janggum Limestone) and Pyeongan Group(Jaesan and Dongsugok Formations)] metasedimentary rocks and Mesozoic granitoid(Chunyang granite.) This study is to interpret geological structure of the North Sobaegsan Massif in the Jang-gunbong area by analysing rock-structure and microstructure of the constituent rocks. It indicates that its geological structure was formed at least by four phases of deformation after the formation of gneissosity(S0) in the Wonnam Formation and bedding plane(S0) in the Paleozoic metasedimentary rocks. The first phase deformation(D1) formed tight isoclinal fold(F1). Its axial plane(S1) strikes east-west and steeply dips north. Its axis (L1) subhorizontally plunges east-west. The second phase deformation(D2), which was related to ductile shear deformation, formed stretching lineation(L2) and shear foliation(S2). The sense of the shear movement indicates dextral strike-slip shearing(top-to-the east shearing). The third phase deformation(D3) formed open inclined fold(F3). Its axial plane(S3) strikes east-west and moderately or gently dips north. Its axis(L3) subhorizontally plunges east-west. The F3 fold reoriented the original north-dipping S1 foliation and D2 shear sense into south-dipping S1 foliation(top-to-the west shear sense on this foliation) at its a limb. The four phase of deformation(D4) formed asymmetric-type open inclined fold(F4) of NE-vergence with NW striking axial plane(S4) and NW-NNW plunging axis(L4). The F4 fold partly reoriented pre-D4 structural elements with east-west trend into those with north-south trend. Such reorientation is recognized mainly in the Paleozoic metasedimentary rocks.

문경지역에 분포하는 변성 염기성암과 변성 퇴적암에 대한 백악기 화강암의 열변성작용

  • 오창환;김성원;김종섭
    • The Journal of the Petrological Society of Korea
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    • v.2 no.2
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    • pp.74-94
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    • 1993
  • Metabasites and metapelites in the Mungyong area were intruded by Cretaceous granites with radius of 4-8 km. As the distance from granite body increases, the mineral assemblage of metabasite changes from amphibole + plagioclase through amphibole + plagioclase + epidote to amphibole + plagioclase + epidote + chlorite. The compositional variations of amphibole and plagioclase according to the change of metamorphic grade and bulk rock compositions are very complex. Towards the Mungyong Cretaceous granite body, the mineral assemblage of metapelite changes from chlorite+ muscovite(ch1orite zone) through biotite + chlorite + muscovite(biotite zone) to andalusite+biotite + muscovite${\pm}$chlorite or cordierite+ biotite+ muscovite${\pm}$chlorite(cordierite zone). The estimated metamorphic conditions of cordierite zone are 480~$580^{\circ}C$ 1.5-3.3 kb. The theoretical study on the thermal metamorphism caused by the Cretaceous granite with radius longer than 4 km in the Mungyong area suggests the followings: The degree of metamorphism is mainly determined not by the size of granite body but by the temperature of granite intrusion; The country rocks within 2 km from Cretaceous granite have undergone metamorphism with temperature higher than $500^{\circ}C$, which is consistent with the petrological study in the Mungyong area. Mungyong Cretaceous granite caused a low P/T thermal metamorphism to the country rocks; the amphibolite facies metamorphism to the country rocks within 1-2 km from the granite body and the epidote-amphibolite and greenschist facies metamorphism to the country rocks within 2-5 km.

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Geological Structure of Precambrian to Paleozoic metasedimentary rocks in the Janggunbong area, Korea-Crustal evolution and environmental geology of the central part of the North Sobaegsan massif, Korea- (장군봉지역 선캠브리아대-고생대 변성퇴적암류의 지질구조-북부 소백산육괴의 중앙부지역의 지각진화와 환경지질)

  • 강지훈;김형식;오세봉
    • The Journal of the Petrological Society of Korea
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    • v.6 no.3
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    • pp.224-259
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    • 1997
  • The Janggunbong area(this study area) at the central-south part in the North Sobaegsan Massif, Korea, consists mainly of Precambrian(Wonnam and Yulri Formations)-Paleozoic [Joseon Supergroupuangsan Quarzite, Dueumri Formation and Janggun Limestone) and Pyeongan Group (Jaesan and Dongsugok Formations)l metasedimentary rocks and Mesozoic granitoid(Chunyang granite). This study is to interpret geological structure of the North Sobaegsan Massif in the Janggunbong area by analysing rock-structure and microstructure of the constituent rocks. It indicates that its geological structure was formed at least by four phases of deformation after the formation of gneissosity(S0) in the Wonnam Formation and bedding plane(S0) in the Paleozoic metasedimentary rocks. The first phase deformation(D1) formed tight isoclinal fold(F1). Its axial plane(S1) strikes east-west and steeply dips north. Its axis(L1) subhorizontally plunges east-west. The second phase deformation(D2), which was related to ductile shear deformation, formed stretching lineation(L2) and shear foliation(S2). The sense of the shear movement indicates dextral strike-slip shearing(topto-the east shearing). The third phase deformation(D3) formed open inclined fold(F3). Its axial plane(S3) strikes east-west and moderately or gently dips north. Its axis(L3) subhorizontally plunges east-west. The F3 fold reoriented the original north-dipping S1 foliation and D2 shear sense into south-dipping S1 foliation(top-to-the west shear sense on this foliation) at its a limb. The four phase of deformation(D4) formed asymmetric-type open inclined fold(F4) of NE-vergence with NW striking axial plane(%) and NW-NNW plunging axis(L4). The F4 fold partly reoriented pre-D4 structural elements with east-west trend into those with north-south trend. Such reorientaion is recognized mainly in the Paleozoic metasedimentary rocks.

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Stabilizing Soil Moisture and Indoor Air Quality Purification in a Wall-typed Botanical Biofiltration System Controlled by Humidifying Cycle (가습 주기에 따른 벽면형 식물바이오필터의 토양 수분 안정화 및 실내공기질 정화)

  • Lee, Chang Hee;Choi, Bom;Chun, Man Young
    • Horticultural Science & Technology
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    • v.33 no.4
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    • pp.605-617
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    • 2015
  • The ultimate goal of this research is to develop a botanical biofiltration system that combines a green interior, biofiltering, and automatic irrigation to purify indoor air pollutants according to indoor space and the size of biofilter. This study was performed to compare the stability of air flow characteristics and removal efficiency (RE) of fine dust within a wall-typed (vertical) botanical biofilter depending on humidifying cycle and to investigate RE of volatile organic compounds (VOCs) by the biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be suitable for indoor space utilization. As a result, relative humidity, air temperature, and soil moisture content (SMC) within the biofilter showed stable values regardless of three different humidifying cycles operated by the metering pump. In particular, SMCs were consistently maintained in the range of 27.1-29.7% during all humidifying cycles; moreover, a humidifying cycle of operating for 15 min and pausing for 45 min showed the best horizontal linear regression (y = 0.0008x + 29.09) on SMC ($29.0{\pm}0.2%$) during 120 hour. REs for number of fine dust (PM10) and ultra-fine dust (PM2.5) particles passed through the biofilter were in the range of 82.7-89.7% and 65.4-73.0%, respectively. RE for weight of PM10 passed through the biofilter was in the range of 58.1-78.9%, depending on humidifying cycle. REs of xylene, ethyl benzene, total VOCs (TVOCs), and toluene passed through the biofilter were in the range of 71.3-75.5%, while REs of benzene and formaldehyde (HCHO) passed through the biofilter were 39.7% and 44.9%, respectively. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was very effective for indoor air purification.

Development of a 2-fluid Jet Mixer for Preventing the Sedimentation in Livestock Liquid Manure Storage Tank (가축분뇨액비저장조 침전물 퇴적 방지를 위한 2류체 제트노즐식 교반장치 개발에 관한 연구)

  • Yu, B.K.;Hong, J.T.;Kim, H.J.;Kweon, J.K.;Oh, K.Y.;Park, B.K.
    • Journal of Animal Environmental Science
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    • v.18 no.3
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    • pp.207-220
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    • 2012
  • There are around 7,500 manure tanks to treat the manures from pigs in Korea. In the tank, there are too much sediments deposited on the base and wall, which causes low efficiency of stock capacity and manure fermentation. In order to minimize sediments and to ferment manure effectively, we developed a 2-fluid jet mixer for mixing sediments in liquid livestock manure tank. For developing the prototype, we tested a factorial experimental system with various nozzles, and simulated CFD models with two kinds of nozzle arrangement. From the results of factorial experiment and CFD simulation, we concluded the dia. ratio of primary : secondary nozzle should be 1:2 and the nozzles should be arranged at the same distances toward to the circumferential direction. With this results, we manufactured a 2-fluid jet mixer which is consists of four 2-phase nozzles, centrifugal slurry pump and root's type air blower. And, we carried out the performance test of the prototype in the round shaped liquid manure tank in the farm. The performance test results showed that the uniformity of TS (Total Solid) and VS (Volatile Solid) was raised from 21.3 g/L, 13.3 g/L In steady state to TS and VS to 23.0 g/L, 14.1 g/L in the mixing operation. Therefore, we could conclude that the prototype of 2-fluid mixer could make the solid material which could be sediments in the tank not to be deposited in the tank and to be contacted to air bubbles which could enhance the efficiency of the fermentation of livestock manure.

Analysis of Cost Structures of National R&D Programs for Effective National R&D Management (국가연구개발 정률예외사업의 원가구조분석을 통한 합리적인 사업관리방안)

  • Cho, Seong-Pyo;Ha, Seok-Tae;Hwang, Myung-Ku
    • Journal of Technology Innovation
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    • v.25 no.2
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    • pp.153-179
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    • 2017
  • Korean government has granted fixed indirect cost rates to several exceptional R&D programs which is lower than the predetermined rate by the government. It has been needed to evaluate the validity of exceptional R&D programs and determine the optimal indirect costs rate of the programs. This study analyzes the cost structure and explores drivers of indirect costs of exceptional R&D programs and evaluates the validity of current indirect costs rates. Finally, we propose the formulas for indirect costs rates of exceptional R&D programs. We analyze the cost structure of the exceptional R&D programs. Equipments and material costs are 50% in infra building program. Scholarship to students is 43% in HRD program. Equipments and material costs are 50% and R&D activity costs are 31% in international R&D program. Main cost components of evaluation program are salary(37%), R&D execution costs(21%) and R&D activity costs(19%). We propose three formulas of indirect costs for exceptional programs. 1) The cost items with exceptionally large amount are excluded in the base of formula for indirect costs. 2) Fixed indirect cost rate is applied for specific R&D programs. 3) Upper bound is set for the cost items with exceptionally large amount in the calculation of indirect costs rate. Our proposal is expected to contribute to the improvement of the efficiency of national R&D programs.

The Influence of Private Health Insurance on Admission among Some Patients with Cervical or Lumbar Sprain (민영의료보험 가입이 일부 경·요추부 염좌 환자의 입원에 미치는 영향)

  • Jang, Dong-Ryul;Kang, Myung-Geun
    • Journal of agricultural medicine and community health
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    • v.37 no.2
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    • pp.84-95
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    • 2012
  • Background: In Korea, private health insurance has neglected to induce externality on national health insurance by moral hazard. Therefore, we conducted this study in order to explore the influence of private health insurance on unnecessary medical utilization among patients with cervical or lumbar sprain. Method: The study examined a population of 449 patients (admission, 384; out-patient; 85) diagnosed with simple cervical or lumbar sprain without neurological symptoms at 20 small hospitals or clinics in Gwangju and Jeollanam provinces from Jul. 1 to Aug. 31 2008. The data were collected using structured, self-administrated questionnaire which collected information such as whether or not the patient was admitted (as a dependent variable), whether or not they had private health insurance (as a independent variable), and covariates such as socio-demographic characteristics, the factors related to the sprain, and characteristics of the insurance provider. Results: From hierarchical multiple logistic regression analysis, it was found that the admission rate of patient with private health insurance was higher than that those without it (Odds ratio=3.31, 95% Confidence interval; 1.14-9.58), meaning that private health insurance was an independent factor influencing the admission of patients with these conditions. Other determinants of admission were patient age and physician referral. Conclusions: This study is the first empirical study to explore the influence of private health insurance on inducing moral hazard in admission services, specifically among patients with cervical or lumbar sprain. Regulation of benefits provided by private health insurance may be necessary, as the effect of this moral hazard may mean existence of externality.

Relations between Wave and Wind at 5 stations around the Korean Peninsula (한반도 주변 해역 5개 정점에서 파랑과 바람의 관계)

  • Ko Hee-Jong;Pang Ig-chan;Kim Tae-hee
    • Journal of the Korean earth science society
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    • v.26 no.3
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    • pp.240-252
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    • 2005
  • The relationships between wave and wind around the Korean Peninsula have been analyzed with the data from the buoys moored at five stations (Dugjug-do, Chilbal-do, Geomoon -do, Geoje-do, Donghae) by Korea Meteorological Administration. Generally, the relationship between wave and wind is the highest at the stations in the West Sea and the lowest at the stations in the South Sea, and the middle at the station in the East Sea. The characteristics shown at each station are as follows. Highest wave is developed at Chilbal-do with strong northwesterly wind in winter because the sea is opened in the wind direction and wave is amplified by shoaling effect. At Chilbal-do, wave directions coincide with wind directions relatively well. On the other hand, waves are not fully developed at Dugjug-do in winter due to limited fetch since the sea is blocked by Hwanghae-do in the northwest direction. The limitation in fetch is more serious at the stations in the South Sea. In the South Sea, the direction of dominant northerly wind is blocked by land so that wave heights are small even with very strong northerly wind. In the South Sea, whatever wind direction is, waves dominantly come in the direction from the East China Sea, which are from the south at Geomoon-do and the southwest at Geoje-do. At these directions, waves are coming even with weak wind. At the station in the East Sea, waves are highly developed due to vast area, but not so high as in Chilbal-do because wind and wave directions do not coincide in many cases. As shown, wind direction is important in the wave development as well as wind speed. The reason is that the fetch is determined by wind direction. In the case of long-lasted wind with fixed direction at Chilbal-do and Dugjug-do, wave directions are well coincident with wind directions and wave heights increase with response time, which is the duration between the highest wind and wave. However, in the case of disagreement between wind and wave directions at the station in the East Sea, wave heights do not increase as highly as at Chilbal-do and Dugjug-do in spite of strong wind and longer response time. The results show us that waves are highly developed with strong wind, long fetch, and long duration, and also show that wave development ratios are different at different stations due to environmental factors such as the direction towards sea or land, bottom topography, and the scales of adjacent seas.