• Title/Summary/Keyword: cold weather condition

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

  • Kim, Young-Jin;Baek, Tae-Ryong;Lee, Sang-Soo;Won, Chul;Kim, Dong-Seok
    • Journal of the Korea Concrete Institute
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    • v.15 no.2
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    • pp.254-262
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    • 2003
  • In this study, the results of applying cold weather concreting mixed with Accelerator for Freeze Protection(AFP) to full scale structures are presented. Since the determination of W/C and amount of AFP significantly have an effect on strength gain and protection of frost damage in early, a full investigation is needed to determine these values at stage of nux design. The flowability of fresh cold weather concreting with AFP was similar to the same W/C. Lower loss of workability and initial slump flow of concrete using superplasticizer of polycarboxylic ester than that of melamine sulphonate showed that polycarboxylic ester was more effective on elapsed time. Temperature histories of specimens located in insulation boxes at the site was similar to that of structures. Thus, it is cleared that simple adiabatic curing method is effective for evaluating in-place concrete strength than specimens cured by sealing method. The investigation results of development of compressive strength of cold weather concreting included AFP with curing methods by logistic curves indicated that AFP can be effective to gain strength at lower temperature than normal curing temperature. In field testing, vinyl sheets were placed over the concrete sections and AFP enabled concrete to gain $5N/{mm}^2$ to protect frost damage in early ages and specified compressive strength of concrete at 28 days under average temperature of $-2^{\circ}C$ (lowest temperature was $-12^{\circ}C$) during site application.

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

  • Kim, Kyoung-Min;Won, Cheol;Hong, Sang-Hee;Kim, Gi-Cheol;Oh, Sun-Kyo;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.913-918
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    • 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.

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

  • Han, Kwang-Hee;Ku, Ho-Young;Bae, Hyo-Jun;Kim, Baek-Min
    • Atmosphere
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    • v.32 no.3
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    • pp.207-221
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    • 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.

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

  • Baek, Dae-Hyun;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.558-561
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    • 2007
  • In this paper, non working day for the construction project in Cheongju and Chungju region considering weather condition was estimated. In Cheongju region, non working day for outside and half outside work was 157days and for interior work 144days. For Chungju region, non working day for outside and half outside work was 160days and for interior work 144days. Non working day affected by temperature was 144 days at both Chungju and Cheongju. Non working day due to low temperature was 109 days and it due to high temperature was 45 days for Choengju. In Chungju, it was 11Sdays for cold weather, while it due to hot weather was 29 days.Non working day due to rainfall was 23 days at both region. To reduce the deviation between estimated non working days and measured ones, proper selection of the duration is required.

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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
    • Archives of Craniofacial Surgery
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    • v.22 no.2
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    • pp.110-114
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    • 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.

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

  • Lee, Sang-Soo;Won, Cheol;Park, Sang-Joon;Kim, Dong-Seok
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.2
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    • pp.151-156
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    • 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
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    • v.14 no.3
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    • pp.27-48
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    • 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.

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Arduino Sensor based on Traffic Safety System using Intelligence

  • Choi, Myeong-Bok;Hong, You-Sik
    • International Journal of Internet, Broadcasting and Communication
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    • v.9 no.1
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    • pp.18-23
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    • 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.

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

  • Park, Shin
    • Korean Journal of Construction Engineering and Management
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    • v.7 no.2 s.30
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    • pp.71-80
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    • 2006
  • It is required to study systematical on the concrete quality management to extend structure life because rebuilding effect is reducing under present condition of large sized and high stories structure. Concrete, which shows its intensity by hydrating action and a big change in quality according to hot weather and temperature, produces a lot of quality problem under hot and cold weather. Because of each specification and construction plan which does not have basic standard on site, concrete's quality is irregular and makes some defect. As a result, Dae-gu is fumed out to be the longest area after investigating application period and days focused on 8 cities weather information about t relationship between hot weather circumstance and construction environment. Therefore, we first surveyed the curing construction processing in the region and found out the problem of quality management. Then figure out the way of solution. Moreover, we integrated curing quality management, which is applied differently to each site, to have equal quality and to reduce defect from construction site. And then, based on various test of construction condition and analysis of quality management item, we suggest effective concrete quality management to make curing construction standard guide and plan under hot weather.

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

  • Han, Young-Ho
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.13 no.1
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    • pp.17-25
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    • 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.

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