• 제목/요약/키워드: reduction formula

검색결과 304건 처리시간 0.023초

Estimation of stormwater interception ratio for evaluating LID facilities performance in Korea

  • Choi, Jeonghyeon;Lee, Okjeong;Lee, Jeonghoon;Kim, Sangdan
    • Membrane and Water Treatment
    • /
    • 제10권1호
    • /
    • pp.19-28
    • /
    • 2019
  • To minimize the impact of urbanization, accurate performance evaluation of Low Impact Development (LID) facilities is needed. In Korea, the method designed to evaluate large-scale non-point pollution reduction facilities is being applied to LID facilities. However, it has been pointed out that this method is not suitable for evaluating the performance of relatively small-scale installed LID facilities. In this study, a new design formula was proposed based on the ratio of LID facility area and contributing drainage area, for estimating the Stormwater Interception Ratio (SIR) for LID facilities. The SIR was estimated for bio-retentions, infiltration trenches and vegetative swales, which are typical LID facilities, under various conditions through long-term stormwater simulation using the LID module of EPA SWMM. Based on the results of these numerical experiments, the new SIR formula for each LID facility was derived. The sensitivity of the proposed SIR formula to local rainfall properties and design variables is analysed. In addition, the SIR formula was compared with the existing design formula, the Rainfall Interception Ratio (RIR).

반파 구조물에 의한 월파 저감 효과 분석 (Analysis of the Effect of Reducing Wave Overtopping by Wave Return Walls)

  • 오상호
    • 한국해안·해양공학회논문집
    • /
    • 제28권1호
    • /
    • pp.1-6
    • /
    • 2016
  • 수리실험을 통해 반파 구조물에 의한 월파 저감 효과를 정량적으로 분석하는 연구를 수행하였다. 원호 호안 및 경사 호안 모형에 대한 월파량을 계측하고 반파 구조물에 의한 월파량 저감 예측식과 비교하였다. 월파량이 비교적 많은 경우($q/{\sqrt{gH^3_s}}>10^{-3}$)에는 예측식과 실험 결과가 대체로 잘 일치하였으나, 월파량이 이보다 적은 경우에는 예측식과 실험의 편차가 크게 나타났다. 이러한 점을 고려하여 반파 구조물에 의한 월파 저감 효과를 보다 잘 예측할 수 있는 산정식을 개발할 필요가 있다.

(-)-Hydroxycitrate를 이용한 비만 여성의 체중 조절 프로그램 실시 및 효과 평가에 관한 연구(I) (The Effect of (-)-Hydroxycitrate on Weight Control Program in Obese Women -I : Effect on Anthropometric Parameters-)

  • 문수재
    • Journal of Nutrition and Health
    • /
    • 제30권2호
    • /
    • pp.155-169
    • /
    • 1997
  • This study investigated the effect of weight control by using the commercial appetite suppressant ((-)-hydroxycitric acid(HCA) formula) and nutrition education on 72 obese women over a period of 8 weeks. During the study it conducted nutritional education for women to control their weight, thus analyzed their changes in anthropometric variables. All obese women were randomized in a double-blind method to consume either HCA(HCA group : experimental group) or placebo(placebo group : control group). Two groups were also divided randomly into 2 groups combined with commercial formula diet in 1 meal a day(HD group and PD group : HCA + gormula diet and placebo + formula diet) or not(HO group and conducted with 4 groups(HD, HO, PD, and PO group). All subjects were assigned to consume 800-1500kcal/d balanced diet which is 500kcal less than their usual energy requirement. To evaluate the effect of the weight control program, weight, percent of body fat, waist and hip circumferences, and 5 skinfold thickness were measured up to 5 times in all obese women. The mean weight of the subjects at the onset of the study was 76.5$\pm$10.6kg. The mean body mass index(BMI) wa 30.1$\pm$3.8 and it was in the upper 5 percentile of mean BMI of Korean women. At the end of the program, mean weight loss was 3.5kg after 2 weeks(p<0.001), and 5.8kg after 4 weeks(p<0.001). The waist, hip ratio(WHR) and skinfold thickness measurements of biceps, triceps, subscapular, suprailiac and abdominum showed significant reduction over the entire study period(p<0.05). These outcome were evaluated by effect of nutritional education and counselling. The reduction of % of body fat was significantly different among the 4 groups. Women who administrated HCA demonstrated more change in weight, BMI than the placebo group. There was also significant reduction in body composition (% of body fat, WHR, and skinfold thickness) than the other groups. The HD group which was administrated HCA combined with formula diet was more decreased than other groups. It showed that this program using commercial HCA and formula diet induced not only a change in weight but also a change in body composition. The outcome of this study suggests that HCA has a more effctive change on weight control which is carried out with nutritional education and counselling.

  • PDF

비탄성 이력응답 및 지진특성을 반영한 변위증폭계수에 관한 연구 (A Study of Displacement Amplification Factors Considering Hysteretic Behavior of Structural Systems and Earthquake Characteristics)

  • 송종걸;김학수
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
    • /
    • pp.777-782
    • /
    • 2007
  • Displacement amplification factor can be used to estimate inelastic displacement demands from elastic displacement demands, The simple formula for displacement amplification factor considering hysteretic behavior of structural system and earthquake characteristics is proposed. And the effects of several parameters such as displacement ductility, strain hardening ratio, period, characteristics of earthquakes and hysteretic models for the displacement amplification factor are evaluated. Accuracy of the proposed formula is evaluated by comparing the displacement amplification factors estimated by existing and proposed formula with those calculated from inelastic time history analysis. The displacement amplification factors by proposed formulas provide a good agreement with those calculated by inelastic time history analysis.

  • PDF

도로환경에 따른 최적의 방음벽 높이 산정식 연구 (Development of an Optical Height Formula for Noise Barrier Considering the Road Environment)

  • 임유진;문학룡
    • 한국도로학회논문집
    • /
    • 제17권4호
    • /
    • pp.63-68
    • /
    • 2015
  • PURPOSES : A study on the efforts to minimize the road traffic noise has been underway. An attempt has been made to measure the noise level using a noise map; however, the attempt is limited to certain areas only. In general, a noise barrier is employed to prevent road traffic noise; however, unplanned noise barriers developed without considering the surrounding environment, including excessively high walls, cause problems such as infringement on prospect right. Noise ceiling at daytime in Korea is 68 dB(A), which is relatively higher than in other countries. METHODS: The noise barrier used mainly for road noise reduction was analyzed to estimate the optimal height. Related variables such as road width, the height of the upper part, distance to the building, and angle (for instance, $30^{\circ}$). RESULTS : A formula to calculate the optical height of the noise barrier, considering the road environment (i.e., parameters such as road width and distance to building), was developed in this study in an attempt to mitigate the noise generated from the road. CONCLUSIONS : The formula to calculate the noise barrier is expected to lead to cost saving, accurate installation of barriers, and protection of the right of prospect.

포뮬러 형태의 자작자동차 설계 및 제작 (Design and Manufacture of a Hand-made Vehicle Based on a Formula)

  • 이수진;정원선;김근비;김성걸
    • 한국생산제조학회지
    • /
    • 제24권5호
    • /
    • pp.568-575
    • /
    • 2015
  • A hand-made vehicle with a formula (VF-1) was designed and manufactured with the aim of realizing a lightweight and high-performance vehicle. The driver's body weight and stiffness of the frame were considered. The vehicle was equipped with a one-cylinder Exiv 250 engine with intake manifold potting for realizing weight reduction, high performance, and low cost. The suspension system for the formula was designed through the analyses and tests of vehicle motion and equipment. In a steering system, anti-Ackerman geometry was introduced to increase the transverse force during cornering. A full electric paddle shift system was adopted to decrease the braking distance. For protection against the distortion and warping of the frame, tungsten inert gas (TIG) welding technology was used.

방음실에 의한 공장설비 소음의 감쇠 효과에 관한 연구 (A Study on Sound Attenuation of Plant Noise by Enclosure)

  • 윤세철;이해경
    • 한국안전학회지
    • /
    • 제9권4호
    • /
    • pp.119-124
    • /
    • 1994
  • The considerations in the noise control by enclosure are the rise of temperature and sound pressure, transmission loss, absorption coefficient of the materials, the structure of the soundproof panels, an opening and coincidence frequency. But it is very difficult that we obtain the accurate data about those in design, so, the noise reduction after enclosing does not correspond with the calculation. The difference of the noise reduction between the calculation and the measurement was 8.2dBA, and we can obtain the approximate result as the following formula which correct 10dBA, safely.

  • PDF

Early Life Factors Influencing the Risk of Obesity

  • Lifschitz, Carlos
    • Pediatric Gastroenterology, Hepatology & Nutrition
    • /
    • 제18권4호
    • /
    • pp.217-223
    • /
    • 2015
  • The obesity epidemic is a worldwide problem. Factors predisposing to obesity include genetics, race, socioeconomic conditions, birth by cesarean section, and perinatal antibiotic use. High protein (HP) content in infant formulas has been identified as a potential culprit predisposing to rapid weight gain in the first few months of life and leading to later obesity. In a large multicountry study the effects of lower protein (LP) formula (1.77 and 2.2 g protein/100 kcal, before and after the 5th month, respectively) were compared to those of higher protein (2.9 and 4.4 g protein/100 kcal, respectively). Results indicated that at 24 months, the weight-for-length z score of infants in the LP formula group was 0.20 (0.06, 0.34) lower than that of the HP group and was similar to that of the breastfed reference group. The authors concluded that a HP content of infant formula is associated with higher weight in the first 2 years of life but has no effect on length. LP intake in infancy might diminish the later risk of overweight and obesity. At 6 years of age HP children had a significantly higher body mass index (by 0.51; 95% confidence interval [CI], 0.13-0.90; p=0.009) and a 2.43 (95% CI, 1.12-5.27; p=0.024) fold greater risk of becoming obese than those who received the LP. In conclusion, several factors may influence development of metabolic syndrome and obesity. Breastfeeding should always be encouraged. An overall reduction of protein intake in formula non breastfed infants seems to be an additional way to prevent obesity.

튜브 인발공정시 압하량 배분에 관한 연구 (A Study on Reduction Distribution in Tube Drawing Process)

  • 이동활;김동우;김대현;문영훈
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2004년도 춘계학술대회 논문집
    • /
    • pp.35-38
    • /
    • 2004
  • In general, tube drawing process is composed of two steps, so called first drawing and second drawing. Drawing cracks are mainly occurred during the 2nd drawing process due to the improper drawing process. In order to analyze the reduction distribution in successive two-step drawing process, tube drawing process was simulated by finite element method. From the finite element analysis, the balance between first and second reduction is proved to be important factor to prevent drawing cracks. Hence the numerical expression was developed for tube drawing process to distribute even strain and criteria curves that can predict the safe drawing region were also proposed using this numerical formula.

  • PDF

Field trial on the control effect of fipronil bait against German cockroaches

  • Ree Han-Il;Lee In-Yong;Jeon Soung-Hoo;Yong Tai-Soon
    • Parasites, Hosts and Diseases
    • /
    • 제44권3호
    • /
    • pp.255-257
    • /
    • 2006
  • A field trial on the control effect of fipronil poison bait against German cockroaches (Blatella germanica) was carried out at different restaurant types in Sinchon, Seoul, Republic of Korea. Monitoring was performed applying food baited traps for 2 days per week. Reduction rates of German cockroaches by applying fipronil baits were 90.9% at Korean restaurants, 96.4% at Chinese restaurants, and 89.4% in beer hall kitchens after 4 weeks of the treatment. Overall average of the reduction rate was 93.9%. As the natural reduction rate at untreated restaurants was 11.5% after 4 weeks, a correction of the average reduction rate by applying the Abbot formula was 93.1 %.