• Toxicological Research
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• 제19권3호
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• pp.227-234
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• 2003

2-Bromopropane (2-BP), a halogenated propane analogue, is a substitute for chlorofluorocarbones (CFCs) which have a great potential to destroy the ozone layer and to warm the earth's environment. The present study was undertaken to evaluate the potential adverse effects of 2-BP on pregnant dams and embryo-fetal development after maternal exposure during the gestational days (GD) 6 through 17 in ICR mice. The test chemical was administered subcutaneously to pregnant mice at dose levels of 0, 313, 625 or 1,250 mg/kg/day. All dams were subjected to caesarean section on GD 18 and their fetuses were examined for external, visceral and skeletal abnormalities. In the 1,250 mg/kg group, maternal toxicity included an increase in the incidence of abnormal clinical signs and a decrease in the maternal body weight, body weight gain, and corrected body weight. Developmental toxicity included a decrease in the fetal body weight, a reduction in the placental weight, an increase in the fetal skeletal variation and ossification delay. There were no adverse effects on either pregnant dams or embryo-fetal development in the 313 and 625 mg/kg groups. These results suggest that a 12-day subcutaneous dose of 2-BP is embryotoxic at a maternally toxic dose (i.e., 1,250 mg/kg/day) in ICR mice. In the present experimental condition, the no-observed-adverse-effect level of 2-BP is considered to be 625 mg/kg/day for dams and embryo-fetuses, respectively.

• 대한토목학회논문집
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• 제33권1호
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• pp.207-218
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• 2013

대형 사력댐의 내진성능 평가에서 필히 요구되는 입력상수는 사력재료, 코아매질의 전단파 속도이다. 이를 표면파 시험으로 평가하기 위해서는 사력골재의 불연속, 매질의 비균질, 사면 경계면 등 표면파 시험결과의 신뢰도를 떨어뜨리는 조건을 극복해야 한다. 본 연구에서는 이러한 표면파시험의 한계를 극복하기 위하여 기존 빔형성기법의 원리를 응용한 SBF (Short-Array Beamforming) 기법을 제안하였다. SBF 기법은 3~9 m의 짧은 측선과 원거리 발진원을 이용함으로써, 빔형성기법 고유의 장점인 측정자료의 자동화분석뿐만 아니라 근접장 문제의 해결, 국부적 이상대의 발견 등의 기능을 가지도록 개발되었다. 본 연구에서는 이러한 SBF 기법과 IRF(Impulse-Response Filtration) 기법을 활용하여 대형 사력댐의 전단파속도를 신뢰성 있게 평가하는 방법을 정립하였다. 정립된 기법은 사력댐의 사력재료와 유사한 암버럭으로 매립 성토된 철도 노반에서 다운홀 시험, CapSASW (Common-Array-Profiling SASW) 시험과의 비교를 통하여 그 신뢰성과 실용성을 검증하였다.

• 한국습지학회지
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• 제21권spc호
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• pp.9-15
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• 2019

기후변화에 따른 강우패턴의 변화로 인해 가뭄의 발생주기가 짧아지고 있으며 다목적댐의 운영 또한 변화하고 있다. 다목적댐의 물 부족을 사전에 방지하고 안정적인 용수공급을 위한 운영에 대한 중요성은 증가하고 있는 실정이다. 본 연구에서는 현재 다목적댐에 적용중인 운영기준을 기반으로 기후변화 시나리오가 반영된 운영기준을 개발하고 평가하였다. 기후변화가 반영된 기준저수량은 기존대비 평균적으로 34% 증가하는 것으로 분석되었으며, 기존 기준과의 평가결과 기후변화 반영 다목적댐 운영기준을 적용할 경우 용수공급에 어려움이 없을 것으로 분석되었다. 본 연구 결과는 향후 기후변화를 반영한 다목적댐의 기준수립에 도움이 될 것으로 기대한다.

• 한국지반공학회논문집
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• 제17권6호
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• pp.149-162
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• 2001

삼랑진에 위치한 삼랑진양수발전 상.하부댐의 댐마루에 시공 후 종방향 균열이 발생하였다. 이 댐들은 전력을 생산하기 위한 양수발전댐으로 상부댐과 하부댐으로 구성되어 있으며, 매일 10m이상의 수위변화를 받아왔다. 본 논문은 이들 댐중 상부댐에 발생한 종방향 균열의 원인을 찾는데 있다. 균열의 주요 원인은 수위변동으로 인한 것으로 판단되었으며, 이를 검토하기 위해 hyperbolic model을 이용한 수치해석을 수행하였다. 수치해석을 위한 입력자료를 얻기 위해 심벽재료와 사석재료에 대해 일련의 삼축압축시험을 수행하였다. 또한 수위변동으로 인한 주기적인 응력변화를 검토하기 위한 입력자료를 얻기 위해 진동삼축압축시험을 수행하였다. 수치해석결과 반복하중이 작용했을 경우 댐마루에서 깊이 4m까지 구속압력이 음이 되는 것으로 나타났으며, 이로 인해 종방향균열이 발생한 것으로 판단되었다. 이 종방향균열의 깊이는 댐 마루에서 수행한 시험굴에서 확인하였으며, 현장 조사결과와 잘 부합하였다.

• Journal of Nutrition and Health
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• 제29권6호
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• pp.569-577
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• 1996

This study was performed to determine the effect of maternal protein intake on 1) the concentration of immune substances in milk 2) degree of passive immunity to pups via lactation, and 3) specific antibody production to a specific antigen, $\beta$-lactoglobulin(BLG). 4) the effect of passive immunity that pups received from mother during lactation on the production of antibodies when the pups were challenged to the same antigen. Part of the female rats were immunized with BLG before and during pregnancy. The pregnant rats were placed into either 25% or 10% isolated soy protein diet throughout gestation and lactation. After weaning, pups from each group continued to be fed the same diet. At 18 weeks of age, all the pups were challenged with BLG. Total IgA and IgG, lysozyme, BLG-specific IgA and IgG were measured in dam's serum, dam's milk, and pup's serum. Total IgG, and lysozyme in dam's serum and milk were higher in high protein group. Total IgA and IgG in pup's serum remained higher in high protein group from 5 to 18 weeks of age. BLG-specific antibodies were found in the milk and serum of immunized dams, and in serum of pups born to immunized dams but not in the non-immunized group. BLG-specific IgA and IgG were again higher in high protein group and declined with time. The concentration decreased faster in the low proetein group than in the high protein groups. After immunization the pups with LBG, serum BLG-specific antibodies were not differ between rats born to immunized dams and those born to non-immunized dams. Therefore passive immunity rats received via milk as a pup had no effect on the BLG-specific antibody production later in life. This study shows the importance of protein status of mother and strongly support to the endorsement of breast feeding.

• Computers and Concrete
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• 제20권3호
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• pp.275-282
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• 2017

Grouting is an operation often carried out to consolidate and seal the rock mass in dam sites and tunnels. One of the important parameters in this operation is grouting pressure. In this paper, analytical models used to estimate pressure are investigated. To validate these models, grouting data obtained from Seymareh and Aghbolagh dams were used. Calculations showed that P-3 model from Groundy and P-25 model obtained from the results of grouting in Iran yield the most accurate predictions of the pressure and measurement errors compared to the real values in P-25 model in this dams are 12 and 14.33 Percent and in p-3 model are 12.25 and 16.66 respectively. Also, SPSS software was applied to define the optimum relation for pressure estimation. The results showed a high correlation between the pressure with the depth of the section, the amount of water take, rock quality degree and grout volume, so that the square of the multiple correlation coefficient among the parameters in this dams were 0.932 and 0.864, respectively. This indicates that regression results can be used to predict the amount of pressure. Eventually, the relationship between the parameters was obtained with the correlation coefficient equal to 0.916 based on the data from both dams generally and shows that there is a desirable correlation between the parameters. The outputs of the program led to the multiple linear regression equation of P=0.403 Depth+0.013 RQD+0.011 LU-0.109 V+0.31 that can be used in estimating the pressure.

• Earthquakes and Structures
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• 제18권2호
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• pp.201-213
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• 2020

Seismic damages that occurred by the effects of epicenter distance of the earthquake are one of the most important problems for the earthquake engineering. In this study, it is aimed to examine the nonlinear seismic behaviors of concrete gravity (CG) dams considering various epicenter distances. For this purpose, Boyabat CG dam that is one of the biggest concrete gravity dams in Turkey is selected as a numerical application. FLAC3D software based on finite difference method is used for modelling and analyzing of the dam. Drucker-Prager nonlinear material model is used for the concrete body and Mohr-Coulomb nonlinear material model is taken into account for the foundation. Special interface elements are used between dam body and foundation to represent interaction condition. Free-field and quiet non-reflecting boundary conditions are utilized for the main surfaces of 3D model. Total 5 various epicenter distances of 1989 Loma Prieta earthquake are considered in 3D earthquake analyses and these distances are 5 km, 11 km, 24 km, 85 km and 93 km, respectively. According to 3D seismic results, x-y-z displacements, principal stresses and shear strain failures of the dam are evaluated in detail. It is clearly seen from this study that the nonlinear seismic behaviors of the CG dams change depending to epicenter distance of the earthquake. Thus, it is clearly recommended in this study that when a CG dam is modelled or analyzed, distance of the earthquake fault to the dam should be strongly examined in detail. Otherwise, earthquake damages can be occurred in the concrete dam body by the effects of seismic loads.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2003년도 학술발표회논문집(1)
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• pp.219-225
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• 2003

The World Commission on Dams (WCD) in November 2000 published "Dams and Development" as its only and final report. The report proposed "internationally acceptable criteria and standards" Despite the (act that the WCD itself did not regard the report as a blue print, many NGO's strongly support the report and the guidelines, and demand that they be adopted in their current form by funding organizations. The WCD recommendations and guidelines were found to have several "generic" problems, and the proposed guidelines appear unable to be applied as they stand. The authors assume that only several of these guidelines are operational and many of these are either too experimental or theoretical to be put into use. Furthermore, some seemingly "ready for operation" guidelines still need to be enhanced to be really operational in the real world. About 2,000 large dams were constructed in Japan after the Second World War. Various principles and mechanisms were then developed to better address the issues related to involuntary resettlement. The knowledge accumulated through large dam construction projects in Japan may be applied to other countries. The aim of this paper is to identify the lessons, out of the experiences gained in Japan through large dam construction projects in the past, which could be applicable for future large dam construction projects in other nations. The socio-economic settings as well as legal frameworks in Japan may differ other nation. Nevertheless, the following aspects of the experiences gained in Japan are found to be both applicable and useful for future large dam construction projects abroad: (a) Integrity of community in the negotiation process, (b) Provision of alternative occupations, (c) Funding mechanism in the post-project period, (d) Measures needed during planning process, and (e) Making resettlers "shareholders". These lessons may prove useful to enhance the WCD guidelines.

• 한국지반공학회논문집
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• 제19권6호
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• pp.61-70
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• 2003

사력댐은 점토부터 사석에 이르는 다양하고 복합적인 재료로 구성되어 있고, 이에 따른 제체의 투수성 차이 등으로 인해 건설 후의 거동양상은 아주 복잡하게 나타난다. 특히, 건설 이후 계절적 강우 차이로 야기되는 수위변화는 댐의 거동변화를 야기하며, 이런 특성들은 결과적으로 건설 후 댐 거동의 정형화를 어렵게 한다. 건설 후 댐의 거동은 저수위의 변화, 제체침투 등으로 인해 시간 의존적이며 이러한 거동이 건설 후 댐의 열화현상과 어떠한 관계가 있는가를 조사해보는 것은 중요한 의미가 있다. 건설 후 댐 거동정보는 댐 관리는 물론 설계에도 아주 유용한 정보로써 활용될 수 있다. 본 연구에서는 건설 후 발생 가능한 다양한 수위변화조건을 담수, 수위하강, 반복수위의 형태로 이상화하고, 수위변화속도에 따른 시간의존성 거동을 모델링하기 위하여 변위-간극수압의 결합방정식을 이용한 유한요소 해석을 수행하였다. 해석결과는 하중전이, 수압할렬의 가능성, 응력경로 변화 등의 관점에서 분석하였다. 본 연구결과로부터 실제 댐파괴 사례로부터 발견되는 지반공학적 문제에 대한 정량적 이해와 건설 후 댐관리에 있어 댐에 잔존하는 역학적 능력을 고려하여 수위를 제어하는 것이 중요함을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권4호
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• pp.435-439
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• 2000

Records of weight, age, body condition at calving and udder characteristics scores of 425 beef cows and birth weights and periodical weights of their offspring from birth to weaning were analyzed to study the effect of body weight, condition and udder characteristic scores of dams on birth weight and Preweaning growth of their offspring. Dam's body condition (fat reserve) at calving were scored on a scale of 1 to 5 (1=extremely thin and 5=extremely fat) and dam's udder characteristics were scored on a scale of 1 to 7 (l=udder well attached with small teats and 7=at least one quarters not functional). Dams were from three distinct breed groups and were mated in single sire mating groups within each breed group for 45 days. Within each breed group and year, the dams were classified into high, medium and low based on their weights at the time of parturition. The data were analysed using covariance analysis. In general, calves born to heavier dams were heavier at birth and had higher rate of Preweaning growth. The effect of dam's body condition score on the calf birth weight was not significant. However, cows with average body condition score of 2.5 or 3.0 gave birth to calves that had higher pre weaning growth rates up to weaning than those born to calves with higher body condition score. The udder characteristics score did not affect calf birth weight as expected; however, cows with udder score of 3 (udder well attached with large teats) produced calves with higher preweaning growth rate than those with smaller teats. Based on the results, it can be concluded that maintaining animals with average body condition and weight would result in more efficient calf production. In addition, cows with well attached udder and large teats would provide a better maternal environment for Preweaning growth rates of their calves.