• 제목/요약/키워드: Cold Weather Condition

검색결과 91건 처리시간 0.021초

내한촉진제를 사용한 한중콘크리트의 실구조물 적용에 관한 연구 (Application of Cold Weather Concreting with Accelerator for Freeze Protection to Full Scale Structures)

  • 김영진;백태룡;이상수;원철;김동석
    • 콘크리트학회논문집
    • /
    • 제15권2호
    • /
    • pp.254-262
    • /
    • 2003
  • 본 연구는 내한촉진제를 사용한 한중콘크리트의 배합선정, 제조 생산, 타설 및 양생 등 실구조물에 대한 적용성에 관한 것이다. 내한촉진제의 사용량 및 물-시멘트비의 선정이 한중콘크리트의 초기동해방지 및 강도증진성상에 커다란 영향을 주기 때문에 배합설계단계에서 충분한 검토가 필요하다. 내한촉진제를 사용한 굳지 않은 콘크리트의 유동성상은 전반적으로 동일 물-시멘트비에서 유사한 결과를 나타나고 있었으며, 고성능감수제의 종류에 따른 경시변화 검토결과, 초기 플로우 및 유동성 손실이 적게 나타나는 폴리카르본산계 고성능감수제가 멜라민계 보다 우수한 것으로 판단된다. 강도관리용 공시체는 기존의 현장봉함 양생보다는 실구조물의 온도이력과 유사한 경향을 보이는 간이단열방법으로 양생하는 것이 유효할 것으로 판단된다. 로지스틱곡선을 이용하여 각 양생 방법별 내한촉진제를 사용한 한중콘크리트의 강도증진성상을 검토한 결과, 강도증진에 미치는 내한촉진제의 영향이 상온조건보다는 저온조건 하에서 효과가 높은 것으로 나타났다. 내한촉진제를 사용한 콘크리트는 평균 외기온 $-2^{\circ}C$(최저기온$-12^{\circ}C$)에서 간단한 비닐양생만으로 초기동해 방지를 위해 필요한 압축강도 $5N/{mm}^2$의 발현이 가능하였고 재령28일에 목표로 하는 소요강도를 만족시켰다.

내한제 및 단열거푸집에 의한 한중콘크리트 시공의 효율화에 관한 기초적 연구 (슬래브를 중심으로) (A Fundamental Study on the Effectiveness of Cold Weather Concreting Using Anti-freeze Agent and Insulating Form (Focused on the Slab))

  • 김경민;원철;홍상희;김기철;오선교;한천구
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
    • /
    • pp.913-918
    • /
    • 2001
  • This paper investigates insulating effects and strength properties of concrete under cold climate carrying out the experiment with insulating forms on the slab member. According to test results, under $-10^{\circ}C$ of outer temperature, the surface of concrete exposed to outer temperature goes below zero after 10hours since exposed. And, the surface of concrete covered with vinyl and blanket goes below zero after 42hours. However, the surface of concrete covered with insulating materials such as polystyrene foam does not drop below zero until 55hours. And, according to coring sample strength test, compressive strength cured with insulation shows much higher strength than no insulation curing condition and vinyl and blanket curing condition.

  • PDF

2016년 1월 폭설을 동반한 제주도 한파의 원인 재고찰 (Revisit the Cause of the Cold Surge in Jeju Island Accompanied by Heavy Snow in January 2016)

  • 한광희;구호영;배효준;김백민
    • 대기
    • /
    • 제32권3호
    • /
    • pp.207-221
    • /
    • 2022
  • In Jeju, on January 23, 2016, a cold surge accompanied by heavy snowfall with the most significant amount of 12 cm was the highest record in 32 years. During this period, the temperature of 850 hPa in January was the lowest in 2016. Notably, in 2016, the average surface temperature of January on the Polar cap was the highest since 1991, and 500 hPa geopotential height also showed the highest value. With this condition, the polar vortex in the northern hemisphere meandered and expanded into the subtropics regionally, covering the Korean Peninsula with very high potential vorticity up to 7 Potential Vorticity Unit. As a result, the strong cold advection, mostly driven by a northerly wind, around the Korean Peninsula occurred at over 2𝜎. Previous studies have not addressed this extreme synoptic condition linked to polar vortex expansion due to the unprecedented Arctic warming. We suggest that the occurrence of a strong Ural blocking event after the abrupt warming of the Barents/Karas seas is a major cause of unusually strong cold advection. With a specified mesoscale model simulation with SST (Sea Surface Temperature), we also show that the warmer SST condition near the Korean Peninsula contributed to the heavy snowfall event on Jeju Island.

기후조건에 따른 청주지역의 작업불능일 산정 (Non Working Day Estimation in the Construction Project in Cheongju and Chungju Region Considering Weather Condition)

  • 백대현;한민철;한천구
    • 한국건설관리학회:학술대회논문집
    • /
    • 한국건설관리학회 2007년도 정기학술발표대회 논문집
    • /
    • pp.558-561
    • /
    • 2007
  • 본 연구에서는 청주 및 충주지역의 기후조건에 따른 작업불능일수를 산정하였는데, 작업불능일 산정을 위한 통계기간은 1970년대부터 2000년까지의 30년으로 결정하였다. 먼저 총 작업불능일수는 청주지역의 경우 실외 및 반실내 구간이 157일, 실내 구간이 144일로 산정되었고, 충주지역의 경우 실외 및 반실내 구간이 160일, 실내 구간이 144일로 산정되어 두지역간의 별 차이가 없는 것으로 나타났다. 기온에 의한 작업불능일은 청주와 충주지역 모두 144일로 나타났고, 청주는 겨울철에 109일, 여름철에 45일로 나타났으며, 충주는 겨울철에 115일, 29일로 산정되었다. 강수에 의한 작업불능일은 두 지역 모두 23일로 산정되었다. 산정된 작업불능일의 오차를 줄이기 위해서는 통계기간의 변동이 필요할 것으로 판단된다.

  • PDF

Delayed-type retrobulbar hematoma caused by low temperature after reconstruction of inferior blow-out fracture

  • Lee, Da Woon;Kim, Tae Hyung;Choi, Hwan Jun;Wee, Syeo Young
    • 대한두개안면성형외과학회지
    • /
    • 제22권2호
    • /
    • pp.110-114
    • /
    • 2021
  • Retrobulbar hemorrhage is a disastrous condition that can lead to permanent blindness. As such, rapid diagnosis and treatment are critical. Here, we report a patient who presented with retrobulbar hemorrhage following an orbital floor fracture. Restoration of inferior orbital wall with porous polyethylene implant was underwent. Four days after the orbital floor reconstruction, the patient smoked a cigarette outdoors in -3℃ weather. Cold temperature and smoking caused an increase in his systemic blood pressure. The elevated blood pressure increased intraorbital pressure to the extent of causing central retinal artery occlusion and exacerbated oozing. During exploratory surgery, 3 mL of hematoma and diffuse oozing without arterial bleeding were observed. Prompt diagnosis and treatment prevented vision impairment. Few studies have reported on the risk factors for retrobulbar hemorrhage. This case showed that daily activities, such as exposure to cold weather or tobacco smoking, could be risk factors for retrobulbar hemorrhage.

내한촉진제의 종류 및 혼입양 변화에 따른 모르터의 강도특성에 관한 연구 (A Study on the Strength Properties of Mortar Under Various Types and Contents of Accelerators for Freezing Resistance)

  • 이상수;원철;박상준;김동석
    • 한국건축시공학회지
    • /
    • 제2권2호
    • /
    • pp.151-156
    • /
    • 2002
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than constant temperature condition in same maturity.

The Effects of Hot Temperature on Impulsive Behaviors: The Role of Product Types as a Moderator

  • Ahn, Hee-Kyung
    • Asia Marketing Journal
    • /
    • 제14권3호
    • /
    • pp.27-48
    • /
    • 2012
  • Temperature and weather are all around us, quite literally. Furthermore, temperature and weather not only permeate our atmosphere, constantly affecting our visceral states of warmth and coldness, but they metaphorically permeate our language. People, products, and ideas can all be "hot" or "cold." Given this ubiquity, it is perhaps surprising that relatively little research has systematically examined the influence of temperature on choice and judgment. Temperature-related words such as "hot" and "cold" are often used to describe impulsive and calculated behaviors, respectively. These metaphoric connotations of thermal concepts raise the question as to whether temperature, psychological states and decision making are related to each other, and if so, how. The current research examines these questions and finds support for a relationship. Across one field study and one laboratory experiment, I demonstrate that both hot ambient room temperature (Spa) and hot temperature primes (words) trigger decision outcomes in line with the metaphoric association between hot temperature and impulsivity. In the field study, participants were recruited in hot (40-50 degrees Celsius) and cold (10 degrees Celsius) rooms at a spa. Participants were simply asked to indicate their willingness-to-pay (WTP) for three product categories (travel package, birthday dinner, and cell phone). The results showed that participants in the hot room in comparison to those in the cold room were willing to pay more for the same products. Next, I tested if our results would go beyond ambient temperature and would hold if I were to prime temperature concepts by using a different priming method (i.e., subliminal vs. supraliminal). In line with the previous findings in the spa, participants in the hot priming condition were more likely to choose the wrong answer for the bat and baseball question than those in the cold priming condition. In addition, product type (e.g., pleasure vs. necessity) can moderate the effect of hot temperature on impulsivity. Mood and arousal did not mediate participants' responses. My findings seem to suggest that the effects of temperature on decision outcomes can be attributed to metaphoric associations rather than incidental mood or arousal. The current research applies a novel perspective in understanding the relationship between temperature and judgment and decision making. Also, the results have practical implications for packaging, advertising, merchandising, and pricing of goods and services, as well as for public policy and awareness. One of the most natural implications of my findings would be that retailers would be better off carrying more impulse purchase items on hot days. Furthermore, point-of-purchase promotions encouraging impulse purchase is more likely to be effective in retail environments with higher temperature than with lower temperature. In addition, advertisements and product packages evoking hot temperature associations (e.g., beach, sunshine, summer) might lead consumers to pay higher price for the advertised product than those with cold temperature associations.

  • PDF

Arduino Sensor based on Traffic Safety System using Intelligence

  • Choi, Myeong-Bok;Hong, You-Sik
    • International Journal of Internet, Broadcasting and Communication
    • /
    • 제9권1호
    • /
    • pp.18-23
    • /
    • 2017
  • In 2015, 100-car pileup was happened because the safe distance from the car in front did not be kept due to much fog at YoungJong Bridge in South Korea. This is why the road would be benumbed with cold weather in winter. For this weather condition, if the driver of the car in front changed the lane suddenly or suddenly slammed on the brake in fog or freezing area, the braking distance of the real car has to be 2 or 3 times longer than usual. In this paper, we have simulated the function that warns and notice about the fog area or the freezing one in the road using Arduino sensors and Beacon. Also we propose the intelligent traffic system to protect the accidents in winter.

서중(暑中) 환경에서 현장 콘크리트 시험을 통한 양생 품질관리 방안 (A Study on Concrete Curing Quality Management Based on Various Test of Construction Condition under Hot Weather Circumstance)

  • 박신
    • 한국건설관리학회논문집
    • /
    • 제7권2호
    • /
    • pp.71-80
    • /
    • 2006
  • 건축물이 대형화, 고층화되는 현 상황에서는 재건축의 효용성이 감소되므로 구조물의 수명연장을 위한 콘크리트 품질관리의 체계적인 연구가 필요하다. 콘크리트는 시멘트의 수화 반응에 의해 강도가 발휘되며 온도에 따른 품질변화가 매우 큰 재료로서 한중과 서중 같은 시공환경에서 품질문제가 많이 유발된다. 특히 서중환경에 대해서는 콘크리트 표준시방서와 현장별 특기시방서 및 시공계획서 등으로 현장을 관리하고 있으나, 이에 대한규정이 명확하지 않아 현장별로 뚜렷한 기준 없이 임의로 시공되어 품질이 일정하지 않고 각종 하자가 발생하는 실정이다. 이에 서중 환경이 콘크리트의 시공환경과 어떤 관련성이 있는지에 대해 전국 8개 대도시의 기상자료를 중심으로 적용기간과 일수를 조사하고 분석한 결과 대구가 가장 긴 지역으로 판명되었다. 따라서 이 지역의 콘크리트 양생공정에 대한 현장 품질관리 실태를 조사하여 품질관리상 문제점을 파악하고, 그 해결방안이 될 기초 자료를 도출하였다. 또한, 서중 콘크리트 시공에 있어 현장별로 상이하게 적용되고 있는 양생공정의 품질관리 기준을 통합하여 균일한 품질 확보와 하자발생을 줄이기 위해 현장에서 가장 시급히 보완되어야 할 부분에 대한 현장시험과 품질관리 항목의 분석을 통하여 서중 환경시 양생공정의 시공지침과 시공계획서 작성에 필요한 콘크리트 품질관리에 관하여 연구한 논문이다.

북서태평양 명태 어장의 해황 - 2 . 기후의 특성 - (Oceanography in the Waters Adjacent to Kamchatka and Kurile islands in the Northwestern Pacific - II)

  • 한영호
    • 수산해양기술연구
    • /
    • 제13권1호
    • /
    • pp.17-25
    • /
    • 1977
  • For four calender years (1971-1974), daily observations of weather conditions (air temperature, humidity, wind speed, wind direction, cloud amount, fog, precipitation etc.) at six stations in the north western Pacific Ocean are used to calculate mean monthly values and to check extra-conditions. At Petropavlosk and Miko'skoe, where indicate the characteristics of modified continental climate, the temperature and humidity are high in summer, and Iow in winter. At A Dak and She Mya, where indicate the characteristics of warm current type maritime climate, humidity is high in all season and annual range of air temperature is nearly negligible. At Simusir and Vasi!' eva, where indicate the characteristics of cold current type maritime climate, humidity is high in all season and annual range of air temperature is $15^{\circ}C.$ As dry cooling power is relatively high in winter, working condition on deck is bad. Most of fogs are advection fog in the area of cold current type climate in summer.

  • PDF