• Structural Engineering and Mechanics
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• 제62권2호
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• pp.209-224
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• 2017

Elevated water tanks are considered as important structures due to its post-earthquake requirements. Elevated water tank on reinforced concrete frame staging is widely used in India. Different response reduction factors depending on ductility of frame members are used in seismic design of frame staging. The study on appropriateness of response reduction factor for reinforced concrete tank staging is sparse in literature. In the present paper a systematic study on estimation of key components of response reduction factors is presented. By considering the various combinations of tank capacity, height of staging, seismic design level and design response reduction factors, forty-eight analytical models are developed and designed using relevant Indian codes. The minimum specified design cross section of column as per Indian code is found to be sufficient to accommodate the design steel. The strength factor and ductility factor are estimated using results of nonlinear static pushover analysis. It was observed that for seismic design category 'high' the strength factor has lesser contribution than ductility factor, whereas, opposite trend is observed for seismic design category 'low'. Further, the effects of staging height and tank capacity on strength and ductility factors for two different seismic design categories are studied. For both seismic design categories, the response reduction factors obtained from the nonlinear static analysis is higher than the code specified response reduction factors. The minimum dimension restriction of column is observed as key parameter in achieving the desired performance of the elevated water tank on frame staging.

• 한국지역지리학회지
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• 제16권6호
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• pp.623-634
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• 2010

제주도 서부지역에서 밀집하여 나타나는 고가수조는 제주도 농업경관의 큰 특징을 이루고 있다. 본 연구에서는 제주도 서부지역에서 고가수조가 밀집하여 나타나는 원인에 대하여 살펴보았다. 그 결과 고가수조의 밀집은 기후, 수리지질구조, 토양, 지형, 토지이용의 복합적인 영향을 받아 형성된 것임을 알 수 있었다. 특히 제주도의 고가수조는 배수가 양호한 토양, 수리지질 특성으로 인해서 스프링클러를 이용해 지속적으로 물을 공급해야만 하는 재배방식과 연관이 깊다. 본 연구 결과는 제주도 농경지대의 밀집 고가수조 경관이 제주도의 자연환경 아래에서 농부들이 적응하는 과정에서 형성된 독특한 농업경관임을 보여준다.

• Wind and Structures
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• 제4권5호
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• pp.383-398
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• 2001

The paper describes the results of the monitoring of an elevated steel water-tank with unusual shape, 85 m high and 40 m wide. The research was carried out analysing both the static and dynamic behaviour under wind actions. The instruments used (some of which were employed for the first time for this project) are described and the data processing procedures are discussed. Comparison between the experimental results and those obtained through a numerical model gives interesting information both on the structural behaviour and on the characterisation of wind actions.

• Structural Engineering and Mechanics
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• 제67권6호
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• pp.587-601
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• 2018

Elevated water tanks are inverted pendulum type structures where drift limit is an important criterion for seismic design and performance evaluation. Explicit drift criteria for elevated water tanks are not available in the literature. In this study, probabilistic approach is used to determine maximum drift limit for damage state of yielding and damage state of collapse for the elevated water tanks supported on RC frame staging. The two damage states are defined using results of incremental dynamic analysis wherein a total of 2160 nonlinear time history analyses are performed using twelve artificial spectrum compatible ground motions. Analytical fragility curves are developed using two-parameter lognormal distribution. The maximum allowable drifts corresponding to yield and collapse level requirements are estimated for different tank capacities. Finally, a single fragility curve is developed which provides maximum drift values for the different probability of damage. Further, for rational consideration of the uncertainties in design, three confidence levels are selected and corresponding drift limits for damage states of yielding and collapse are proposed. These values of maximum drift can be used in performance-based seismic design for a particular damage state depending on the level of confidence.

• 대한설비공학회지:설비저널
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• 제24권5호
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• pp.501-509
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• 1995

• 한국패류학회지
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• 제30권2호
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• pp.127-134
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• 2014

Gonad maturation of Manila clam, Ruditapes philippinarum was induced in this study using a recirculation system over 8 weeks in early spring. Clams used in the experiment were collected in $15^{th}$ April 2010 from the west coast of Korea, as the surface water temperature remained $11^{\circ}C$. To induce gametogenesis and subsequent maturation seawater temperature was elevated $1^{\circ}C$ per day over 10 days to reach $20^{\circ}C$. For the experiment, clams were raised in 120 L quadrangle tank maintained with re-circulated seawater system over 57 days. Water quality parameters including the water temperature, salinity dissolved oxygen, ammonium ion and nitrate levels in the tanks were monitored daily. Mixture of concentrated microalgae including Tetraselmis, Isochrysis, Pavlova and Thalassiosira weissflogii was supplied to clams twice a day, and quantity of the daily ration was adjusted as 3% of clam body dry weight. Histology was applied to examine gonad maturation. Daily monitoring of the water quality parameters indicated that the recirculation system supplied suitable environment to Manila clam; the nitrogenous components stayed below toxic levels (< 0.2 mg/L). At the beginning of the study, clams were mostly in early developing stage. As the seawater temperature reached $20^{\circ}C$, 10 days after the experiment, 20% of clams reached late development at 12 days. First ripe clams were observed at 42 days and 40% of clams were in ripe and ready for spawning at the end of study, 57 days after the experiment. In this study, gametogenesis of Manila clam was successfully induced by elevating water temperature and supplying commercially produced microalgae in a recirculation tank system.

• 한국태양에너지학회 논문집
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• 제25권2호
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• pp.63-69
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• 2005

This study is the survey of a transition procedure of building services systems(heat source, HVAC, water supply) through the survey of existing office buildings, building design documents. The preference & major consideration of system selection is the engineer's opinions. The results of this survey can be used in selection of building services system design. In this survey, "Hot & cold water generator system" and "single duct CAV+FCU system", "Elevated water tank system" are selected. The most important consideration in system selection is the energy saving in heat source system, and comfort in HVAC system, and water pressure in water supply system. They prefer "steam boiler+absorption chiller system" for heat source system, "steam boiler+ice thermal storage system", "hot & cold water generator system", "district heating+absorption chiller system" : "single duct CAV+FCU system" and "single duct VAV+convector system" for HVAC system: and "booster pump system" for water supply system.

• 한국수산과학회지
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• 제34권5호
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• pp.465-472
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• 2001

양식현장에서 선별작업시 처리되는 사육수조의 수심감소와 어류이송에 따른 넙치 (대, 소)와 큰민어의 스트레스 반응을 알아보기 위하여 스트레스 지표로 알려져 있는 혈액학적 요인, 코티졸, 글루코스, 젖산 및 삼투질 농도를 조사하였다. 수심감소에서 넙치대의 Ht는 실험전 $14.6\%$였던 것이 10시간째까지 계속 높아져 $23.5\%$를 보였으나, 실험종료시 (46시간째) $14.4\%$로 회복되었다. 넙치대의 코티졸 농도는 실험개시시에 1.9ng/mL였던 것이 22시간째에 13.7 ng/mL로 높아졌고, 46시간째에는 4.0ng/mL로서 개시시의 수준으로 회복되었다. 큰민어는 4시간째 282.3ng/mL, 22시간째 350.5ng/mL로 높아졌으나, 실험종료시에는 16.0ng/mL로 낮아졌다. 큰민어의 글루코스는 실험개시시 57.0mg/dL로부터 22시간째에는 138.0mg/dL조 유의하게 높아졌다 젖산은 모든 어종에서 유의차가 인정되지 않았다. 어류이송에 따른 넙치대의 RBC는 실험개시시의 $1.9\times10^6 cell/{\mu}L$로부터 실험종료시의 $4.2\times10^6 cell/{\mu}L$로 높아졌다. 큰민어의 Hb는 실험개시시의 9.8g/dL로부터 실험종료시에 20.4g/dL로 개시시 보다 유의하게 높았다. 넙치대의 코티졸 농도는 실험개시시의 1.2ng/mL로부터 이동 1시간째에 95.3ng/mL로 높아졌고, 큰민어도 실험개시시의 5.5ng/mL로부터 1시간째에 175.5ng/mL로 높아졌다. 큰민어의 글루코스는 1, 3시간째 각각 132.5 mg/dL, 129.5 mg/dL로 실험개시시 46.5 mg/dL 보다 높은 수준을 보였다.

• 상하수도학회지
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• 제11권1호
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• pp.33-41
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• 1997

An attempt was made to enhance anaerobic treatment efficiency by adopting the anaerobic sequencing batch reactor(ASBR) process at a thermophilic temperature. Operational characteristics of the ASBR process were studied using laboratory scale reactors and concentrated organic wastewater composed of soluble starch and essential nutrients. Effects of fill to react ratio (F/R) were examined in the Phase I experiment, where the equivalent hydraulic retention time(HRT) was maintained at 5 days with the influent COD of 10g/L. A continuous stirred tank reactor(CSTR) was operated in parallel as a reference. Treatment efficiency was higher for the ASBRs because of continuous accumulation of volatile suspended solids(VSS) compared to the CSTR. However, the rate of gas production and organic removal per unit VSS in the ASBRs was much lower than the CSTR. This was caused by reduced methane fermentation due to accumulation of volatile acids(VA), especially for the case of low F/R, during the fill period. When the F/R was high, maximum VA was low and the VA decreased in short period. Consequently, more stable operation was possible with higher F/R. Effects of hydraulic loading rate on the efficiency was studied in the Phase II experiment, where the organic loading rate was elevated to 3333mg/L-d with the F/R of 0.12. Reduction of organic removal along with rapid increase of VA was observed and the stability of reaction was seriously impaired, when the influent COD was doubled. However, operation of the ASBR was quite stable, when the hydraulic loading rate was doubled and a cycle time was adjusted to 12 hour. It is essential to avoid rapid accumulation of VA during the fill period in order to maintain operational stability of the ASBR.

• Annals of Occupational and Environmental Medicine
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• 제34권
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• pp.28.1-28.12
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• 2022

Background: Haenyeo is a woman who has the job of collecting seafood in the Jeju Sea at an average temperature of 13℃-14℃. The purpose of this study was to examine the cold acclimatization and occupational characteristics of Haenyeo through biomarkers such as orexin and irisin related to heat generation in the body. Methods: Twenty-one Haenyeo and 25 people with similar age, body type, and body mass index were selected as the control group (Control G). In the cold exposure experiment, a climate chamber was set to 5℃ and both feet were immersed in a 15℃ water tank for 30 minutes. Tympanic temperature (T_ty) and skin temperature (T_sk) were measured, and the mean body temperature (mT_b) was calculated. Blood samples were collected before and immediately after the examination. Orexin and irisin levels were analyzed. Results: Orexin levels were elevated after cold stimulation from 12.17 ± 4.44 to 12.95 ± 4.53 ng/mL (Haenyeo group [Haenyeo G], p < 0.01) and 10.37 ± 3.84 to 11.25 ± 4.02 ng/mL (Control G, p < 0.001). Irisin levels were elevated after cold stimulation from 4.83 ± 2.28 to 5.36 ± 2.23 ng/mL (Haenyeo G, p < 0.001) and 3.73 ± 1.59 to 4.18 ± 2.04 ng/mL (Control G, p < 0.001). The difference between Haenyeo G and Control G values in orexin and irisin appears not only in pre-exposure but also in post-exposure (p < 0.05). Conclusions: Our experimental results suggest that Haenyeo G were relatively superior in cold tolerance to Control G under cold exposure conditions. Haenyeo's cold acclimatization is due to the basic differences in pyrogens regarding body temperature control such as orexin and irisin. This means that Haenyeo are advantageous for cold survival.