• Title/Summary/Keyword: Total Pressure Rise

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Factors affecting particle breakage of calcareous soil retrieved from South China Sea

  • Wang, Xinzhi;Shan, Huagang;Wu, Yang;Meng, Qingshan;Zhu, Changqi
    • Geomechanics and Engineering
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    • v.22 no.2
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    • pp.173-185
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    • 2020
  • Calcareous soil is originated from marine biogenic sediments and weathering of carbonate rocks. The formation history for calcareous sediment includes complex physical, biological and chemical processes. It is preferably selected as the major fill materials for hydraulic reclamation and artificial island construction. Calcareous sands possess inter pores and complex shape are liable to be damaged at normal working stress level due to its fragile nature. Thus, the engineering properties of calcareous soil are greatly affected by its high compressibility and crushability. A series of triaxial shear tests were performed on calcareous sands derived from South China Sea under different test conditions. The effects of confining pressure, particle size, grading, compactness, drainage condition, and water content on the total amount of particle breakage for calcareous soil were symmetrically investigated. The test results showed that the crushing extent of calcareous sand with full gradation was smaller than that a single particle group under the same test condition. Large grains are cushioned by surrounding small particles and such micro-structure reduces the probability of breakage for well-graded sands. The increasing tendency of particle crushing for calcareous sand with a rise in confining pressure and compactness is confirmed. It is also evident that a rise in water content enhances the amount of particle breakage for calcareous sand. However, varying tendency of particle breakage with grain size is still controversial and requires further examination.

Risk of Cancer Mortality according to the Metabolic Health Status and Degree of Obesity

  • Oh, Chang-Mo;Jun, Jae Kwan;Suh, Mina
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.22
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    • pp.10027-10031
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    • 2014
  • Background: We investigated the risk of cancer mortality according to obesity status and metabolic health status using sampled cohort data from the National Health Insurance system. Materials and Methods: Data on body mass index and fasting blood glucose in the sampled cohort database (n=363,881) were used to estimate risk of cancer mortality. Data were analyzed using a Cox proportional hazard model (Model 1 was adjusted for age, sex, systolic blood pressure, diastolic blood pressure, total cholesterol level and urinary protein; Model 2 was adjusted for Model 1 plus smoking status, alcohol intake and physical activity). Results: According to the obesity status, the mean hazard ratios were 0.82 [95% confidence interval (CI), 0.75-0.89] and 0.79 (95% CI, 0.72-0.85) for the overweight and obese groups, respectively, compared with the normal weight group. According to the metabolic health status, the mean hazard ratio was 1.26 (95% CI, 1.14-1.40) for the metabolically unhealthy group compared with the metabolically healthy group. The interaction between obesity status and metabolic health status on the risk of cancer mortality was not statistically significant (p=0.31). Conclusions: We found that the risk of cancer mortality decreased according to the obesity status and increased according to the metabolic health status. Given the rise in the rate of metabolic dysfunction, the mortality from cancer is also likely to rise. Treatment strategies targeting metabolic dysfunction may lead to reductions in the risk of death from cancer.

Improving Effect of Powders of Cooked Soybean and Chongkukjang on Blood Pressure and Lipid Metabolism in Spontaneously Hypertensive Rats (자발성 고혈압 흰쥐에서 찐콩과 청국장 분말의 혈압 및 지질대사 개선 효과)

  • 양정례;이숙희;송영선
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.6
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    • pp.899-905
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    • 2003
  • The effects of cooked soybean and a traditional fermented soy product, chongkukjang, on blood pressure and lipid metabolism were studied in spontaneously hypertensive rat (SHR). SHRs were divided into 3 groups (n=10, male), and fed casein, powders of cooked soybean, and chongkukjang as dietary protein sources for 6 weeks. Body weight gain was not different among experimental groups, but food efficiency was increased in groups fed cooked soybean and chongkukjang diets compared to control group. Consumption of cooked soybean and chongkukjang for 6 weeks in SHR significantly suppressed blood pressure rise with aging (p<0.05). Feeding of cooked soybean and chongkukjang to SHR decreased plasma triacylglycerols (p<0.05) by 21.6% and 30.2% and LDL-cholesterol by 30.0% and 27.5%, respectively. Addition of cooked soybean and chongkukjang to the diet resulted in reduction of total lipids and triacylglycerols of liver, while consumption of cooked soybean and chongkukjang resulted in the increase of fecal cholesterol and bile acid excretions, respectively (p<0.05). Cooked soybean and chongkukjang diets down-regulated the activity of hepatic HMG-CoA reductase by 56.4% and 94.5%, compared to control, respectively. From the above-mentioned results, it can be concluded that consumption of cooked soybean and chongkukjang might be helpful in preventing cardiovascular disease by suppressing blood pressure rise and hyperlipidemia.

Effects of Using Carbon Dioxide on Heart Rate and Arterial Blood Pressure during Laparoscopic Ovariohysterectomy in Dogs (개에서 복강경을 이용한 난소자궁절제술시 $CO_2$가스에 의한 기복증이 심박수와 동맥혈압에 미치는 영향)

  • Cho, Seong-Su;Kim, Young-Ki;Park, Se-Jin;Lee, Seung-Yong;Lee, Scott-S.;Lee, Hee-Chun;Lee, Hyo-Jong;Chang, Hong-Hee;Yeon, Seong-Chan
    • Journal of Veterinary Clinics
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    • v.28 no.1
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    • pp.40-45
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    • 2011
  • Cardiovascular changes caused by $CO_2$ pneumoperitoneum during laparoscopic ovariohysterectomy (LOVH) were measured in nine healthy mixed breed dogs ($16.7{\pm}4.6kg$). The dogs were premedicated with the combination of atropine, acepromazine, and butorphanol. General anesthesia was induced with propofol and maintained with isoflurane in oxygen. Controlled ventilation maintained partial pressure of end-tidal $CO_2$ between 35-45 mmHg. The $CO_2$ pneumoperitoneum was maintained at a constant pressure of 12 mmHg and the dog was placed in the $15^{\circ}$ Trendelenburg position as LOVH was performed. Dorsal pedal artery was catheterized for measurements of heart rate (HR) and invasive arterial blood pressure (IBP). Prior to the intraperitoneal insufflation, baseline measurements of HR and IBP were made every minute for a total of 10 min. Then, measurements of HR and IBP were made every 5 min following intraperitoneal insufflation and were also made every 5 min following desufflation for a total of 10 min. The $CO_2$ pneumoperitoneum during LOVH resulted in a significant (P < 0.05) increase in systolic arterial blood pressure at the time of the onset of insufflation. In addition, diastolic and mean arterial blood pressure increased significantly (P < 0.05) at the time of the onset of insufflation and 5 min following insufflation. The mean heart rate did not change significantly during LOVH. Although IBP showed sharp initial rise following the $CO_2$ pneumoperitoneum, the changes were within physiological acceptable limits in these healthy, ventilated dogs.

Effects of Skin Pressure by All-in-one on the Rhythm of Body Temperature During Sleep (올인원에 의한 인체 압박이 수면시의 체온 리듬에 미치는 영향)

  • Jeong, Jeong-Rim;Kim, Hee-Eun
    • Fashion & Textile Research Journal
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    • v.12 no.6
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    • pp.830-836
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    • 2010
  • The purpose of this research was to investigate the effects of skin pressure by wearing all-in-one on the rhythm of body temperature such as skin and rectal temperature which play a crucial role in the nocturnal rhythm. Five healthy female were participated in the study as subjects. The experimental clothing was an all-in-one, one of the foundation, which is worn for shaping the body. The total experimental periods were 5 days. On the 1st day, subjects did not wear the all-in-one (None), and they wore it for about 12 hours per day from 2nd to 5th day (Wearing1~4). Skin and rectal temperature were measured during the entire experimental days to figure out the rhythm of body temperature during sleep. When subjects wore the all-in-one, the gradients of the forearm and calf skin temperature at the sleep onset were significantly smaller than "None". It indicated that the rise of extremities' skin temperature was low on the "Wearing1~4". The decline of rectal temperature in "Wearing 1~4" was smaller than "None". Therefore, the skin pressure by all-in-one may cause the temperature of extremities' skin and rectum to change, resulting the fluctuation of the circadian rhythm, finally it could have effects on the rhythm of sleep.

Mechanical and Operational Factors Affecting the Efficiency of Rice Polishing Machines (정미기의 능률에 미치는 기계적 요인및 작동조건에 관한 연구)

  • No, Sang-Ha
    • Journal of Biosystems Engineering
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    • v.1 no.1
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    • pp.15-15
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    • 1976
  • In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic?iency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet?ween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr?ease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$$$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea?ses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin?ear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num?ber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco?very rates. The higher the rate of increase, the lower were the resulting head rice recoveries.

Mechanical and Operational Factors Affecting the Efficiency of Rice Polishing Machines (정미기의 능률에 미치는 기계적 요인및 작동조건에 관한 연구)

  • 노상하;최재갑
    • Journal of Biosystems Engineering
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    • v.1 no.1
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    • pp.17-48
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    • 1976
  • In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic\ulcorneriency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet\ulcornerween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr\ulcornerease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$ $$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$ The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$ These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea\ulcornerses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin\ulcornerear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num\ulcornerber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco\ulcornervery rates. The higher the rate of increase, the lower were the resulting head rice recoveries.

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A Study on Behaviour and Characteristics of Spark Discharge in Spark Ignition System (스파크 점화 시스템의 방전 거동 및 특성에 관한 연구)

  • Lee Myung Jun;Hall Matt;Ezekoye Ofodike A.;Matthews Ron;Chung Sung Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.1
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    • pp.100-108
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    • 2006
  • Time-resolved current and voltage measurements for an inductive automotive spark system were made. Also presented are measurements of the total energy delivered to the spark gap. The measurements were made in air for a range of pressures from 1-18atm, at ambient temperatures. The measured voltage and current characteristics were found to be a function of many ignition parameters; some of these include: spark gap distance, internal resistance of the spark plug and high tension wire, and pressure. The voltages presented were measured either at the top of the spark plug or at the spark gap. The measurements were made at different time resolutions to more accurately resolve the voltage and current behavior throughout the discharge process. This was necessary because the breakdown event occurs on a time scale much shorter than the arc and glow phases. The breakdown, are, and glow voltages were found to be functions of spark plug resistance, gas density, and spark plug gap as expected from the literature. Spark duration was found to decrease as either pressure or gap was increased. The transition from the arc to glow phase is usually distinguished by a sudden rise in the voltage across the gap. At pressures above about 7atm this transition was not observed suggesting that a glow phase was not present. Energy delivered to the gap increased with increasing pressure. The effective resistance of the spark gap during discharge was about twice as large for the glow phase as the arc phase.

The Field Measurement of Airtightness in the Apartment Buildings (신축공동주택의 기밀성능 실측에 관한 연구)

  • Park, Won seok;Yoon, Jae Ock
    • KIEAE Journal
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    • v.3 no.3
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    • pp.43-50
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    • 2003
  • Nowdays the apartment is a main type of modernized residential buildings. According to the improvement of construction techniques and functions of windows and doors, recent apartments are enhanced air tightness of windows, doors and building envelopes. As Infiltration is decreased and natural ventilation is reduced, energy could be saved in winter. However, indoor air quality is bad. The air Infiltration of a building could be enlarged by physical actions, such as building designs, constructions and reduction of air tightness which is caused by aging. This research analyzes and measures with KNS-4000P (Sapporo air tightness measurement) the air tightness of the high rise apartments which is recently constructed and not occupied yet. With depressurization method, the KNS-4000 installed on the window and the indoor air-leakage was measured. At that time, Air come out from the edge of the windows and doors because of the pressure differences between indoor and outdoor. We measure the amount of the air as effective air leakage areas. This method of depressurization takes less time to measure than other methods and is less affected from other conditions. We measured infiltration of total 56 household, 29 households S apartment (total floor area : $64.42m^2$) in Balan and 29 households D apartment(total floor area : $78.21m^2$) in Chonan. As a result of the field measurements at October 2003, normalized leakage area of D apartment in Cheonan was $2.05cm^2/m^2{\sim}3.49cm^2/m^2$ (average: $2.77cm^2/m^2$) and normalized leakage area of S apartment in Balan is $1.23cm^2/m^2{\sim}1.68cm^2/m^2$ (average: $1.5cm^2/m^2$).

Evaluation of Construction RCB Exterior Wall Formwork according to Placing Height on Nuclear Power Plant

  • Song, Hyo-Min;Sohn, Young-Jin;Shin, Yoonseok
    • Journal of the Korea Institute of Building Construction
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    • v.15 no.6
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    • pp.653-660
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    • 2015
  • Technologies for reducing construction duration are key factors in nuclear power plant construction projects, as a reduction in construction duration at the construction phase leads to a reduction in construction cost and an increase in profits through the early operation of the nuclear power plant. To analyze the constructability of the height of single-layer placement of formwork for the Reactor Containment Building (RCB) exterior wall through lateral pressure according to the height of concrete placement, the deformation criteria for formwork, and a new form design, 'MIDAS GEN (hereinafter referred to as MIDAS)' is used in this study. The cost and workload of formwork are derived according to the unit of height of the RCB exterior wall. Based on the result, it was found that the higher the RCB exterior wall, the higher the material cost, and the less the construction duration and the less the total number of formwork layers. Based on this result, it is believed that the material cost and the construction duration can be appropriately determined according to the formwork height.