• 한국해양공학회지
• /
• 제24권1호
• /
• pp.60-67
• /
• 2010

Recently, there has been an increase in the construction of various types of coastal structures for efficient wave dissipation, seawater exchange, and so on. Among these, a perforated slit caisson has been widely used to reduce the reflected wave energy and the wave pressure on the structure. Therefore, many studies on the wave force on a caisson, as well as the wave reflection from it, have been carried out with laboratory experiments and numerical analyses, considering it as a 2-D problem. However, because a structure like a perforated slit caisson has a variable 3-D shape, waves forces should be considered as a 3-D problem. Therefore, in this paper, a fully-nonlinear 3-D numerical model (LES-WASS-3D) is proposed to examine the reflection characteristics of a perforated slit caisson with two chambers. The numerical model, LES-WASS-3D, was verified in a 3-D wave field by a comparison with existing experimental data for wave reflection coefficients. Then, using the numerical results, the reflection from a perforated slit caisson with two chambers was examined in relation to wave steepness, chamber width, and the shape/porosity of perforated slit.

• Asian-Australasian Journal of Animal Sciences
• /
• 제31권11호
• /
• pp.1738-1746
• /
• 2018

Objective: The aim of the experiment was to assess the effect of increasing amounts of Leucaena leucocephala forage on dry matter intake (DMI), organic matter intake (OMI), enteric methane production, rumen fermentation pattern and protozoa population in cattle fed Pennisetum purpureum and housed in respiration chambers. Methods: Five crossbred heifers (Bos taurus${\times}$Bos indicus) (BW: $295{\pm}6kg$) were fed chopped P. purpureum grass and increasing levels of L. leucocephala (0%, 20%, 40%, 60%, and 80% of dry matter [DM]) in a $5{\times}5$ Latin square design. Results: The voluntary intake and methane production were measured for 23 h per day in respiration chambers; molar proportions of volatile fatty acids (VFAs) were determined at 6 h postprandial period. Molar concentration of VFAs in rumen liquor were similar (p>0.05) between treatments. However, methane production decreased linearly (p<0.005), recording a maximum reduction of up to ~61% with 80% of DM incorporation of L. leucocephala in the ration and no changes (p>0.05) in rumen protozoa population were found. Conclusion: Inclusion of 80% of L. leucocephala in the diet of heifers fed low-quality tropical forages has the capacity to reduce up to 61.3% enteric methane emission without affecting DMI, OMI, and protozoa population in rumen liquor.

• 한국의학물리학회지:의학물리
• /
• 제30권2호
• /
• pp.59-63
• /
• 2019

Purpose: To manage radiation measurement equipment, a web-based management program has been developed in this study. Materials and Methods: This program is based on a web service and Java Server Pages (JSP) and employs compatibility and accessibility. Results: The first step in the workflow has been designed to create accounts for each user or organization and to log in. The program consists of two parts: fields for listed instruments, and measurement information. The instruments for measuring radiation listed in this program are as follows: ionization chambers, survey meters, thermometers, barometers, electrometers, and phantoms. Instrument properties can be put in the recording fields and browsing for associated instruments can be performed. The main part of the program is the cross-calibration for each ion chamber. For instance, the ionization chamber to be used as a relative dosimeter can be registered by cross-calibration data with a reference chamber calibrated by an accredited laboratory. This program supports methods using the central axis transfer theory for cross-calibration for the ionization chambers. The reference and field ionization chambers were placed in a solid water phantom along the beam central axis at two different depths, and then the positions were switched. Each measured value was used for calculating the cross-calibration factor. Conclusions: Because many instruments are used and managed in radiation oncology departments, systematic, traceable recording is very important. The web-based program developed in this study is expected to be used effectively in the maintenance of radiation measurement instruments.

• 한국유체기계학회 논문집
• /
• 제15권6호
• /
• pp.70-76
• /
• 2012

Recently, because people are taking a great interest in the water supply system and the related facilities are getting larger, the surge suppression is very important problem. The waterhammer occurs when the pumps are started or stoped for operation or tripped due to the power failure. As the waterhammer problems as a result of the pump power failure were very serious, these situations were carefully investigated. Accordingly, we carried out both numerical simulations and field tests to confirm the safety of Juam intake pumping station in which had the in-line pumps. In this paper, it was reviewed that the water supply system has the reliability on the pressure surge, in case the air chambers were installed at both the inlet and the oulet of the in-line pumping station. From the numerical simulations, we found that negative pressure occurred at the inlet disappeared and high pressure occurred at the outlet reduced due to the air chambers. And these results of numerical simulations verified by the field tests. The field tests carried out in case of normal start, normal stop, one and two of pumps emergency stop. By results of simulations and field tests, we are sure that Juam intake pumping station in which have the air chambers is safe for the waterhammer. In addition, we suggested the operation methods of facilities for safe maintenance of the pumping station.

• 보건행정학회지
• /
• 제8권1호
• /
• pp.112-134
• /
• 1998

The purpose of this study is to analyze the community participation in regional health planning by using the operational definition of participation channels, and to find out the significant variables of community participation channel which are highly related to the scores of regional health plan. The channels we adopted for the study are recommended in the guidebook for regional health planning. They are performing residents' helath survey, submitting written agreement of publics, holding public hearings, putting publicnotice, conducting community health committee meeting, submitting opinion of chambers and Mayors, and operating task-force for planning. We analyzed the selected data of 8 community participation channels, which were submitted by 141 rural health centers for the pursuit of governmental subsidy in 1997. The major findings of this study are as follows; 1. In the process of regional health planning, 88.7% of rural community health centers have performed the residents' health survey, 14.9% submitted written agreement of publics, 11.3% held public hearings, 39.0% put public notice, 46.8% conducting community health committee meeting, 48.9% submitted opinion of chambers, 61.7% submitted opinion of Mayors and 25.5% operated task-force for planning. The result shows that most of community participation channels have been utilized at very low rates, except the residents' health survey. 2. We have analyzed the impact of these community participation channels on the regional health plan scores. In the multiple regression model, we set the regional health plan score as the dependent variable., and the use of participation channels as the idependent variables(1 if the channels are used, 0 otherwise). Finally, the regression analyses show that two channel variables, opinion of chambers and public notice, were the significant positive channel variables on the score of community health plan.

• 한국양식학회지
• /
• 제16권4호
• /
• pp.252-256
• /
• 2003

양식장에서 생성되는 어류의 노폐물이나 미섭취되고 남은 사료분은 고농도의 질소와 인을 함유하고 있으나 미처리된 상태로 처리하고 있어 그에 따른 처리방안이 요구된다. 본 연구에서는 기존의 처리공정의 대용으로 생태공학적 처리로서 경제적으로 질소와 인 제거를 위해 실내재배조에 물상추를 적용하였다. 앙식장 배출수 처리를 위한 생물여과상의 처리효율을 향상시키기 위하여 물상추 여과조를 설치하여 다양한 조건하에 시도되었다. 실험 재료인 수초는 물상추를 재배하였고, 6개의 수조(62${\times}$60${\times}$86cm)에 재배조 용량이 80 L가 되도록 채우고 수리학적 체류시간(hydraulic retention time; HRT)을 1, 2, 4, 8일로 하여 운영하였다. HRT 8일인 경우 1차 배출수를 대상으로 하였을 경우 BOD, T-N, T-P의 제거율은 92.8, 79.0 및 93.6%로 각각 나타났다.

• 한국항공우주학회지
• /
• 제37권10호
• /
• pp.1027-1037
• /
• 2009

우주발사체용 30톤급 액체로켓엔진 재생냉각 연소기 개발과정에 관하여 기술하였다. 이중추진제 동축 와류형 분사기 개발에서부터 시작하여 축소형 연소기를 통해 요소기술을 검증하고 개발된 기술을 실물형 연소기에 적용하였다. 총 5기의 실물형 연소기 개발시제를 사용하여 점화성능, 연소안정성, 연소성능, 냉각성능, 내구성 등의 검증을 수행하였다. 이 과정에서 총 46회의 실물형 연소기 연소시험을 실시하였고 이 중 23회는 기폭장치를 이용한 연소안정성 평가시험을 병행하였다. 시험 결과 30톤급 재생냉각 연소기는 연소 성능 및 연소안정성 요구사항을 모두 만족시켜 단품 개발이 성공적으로 완료된 것으로 평가하였다.

• Animal Bioscience
• /
• 제37권1호
• /
• pp.142-150
• /
• 2024

Objective: This study was conducted to assess effects of heat stress on growth performance, physiological parameters, and blood profiles of Hanwoo steers during early-fattening period in climate chambers. Methods: Four Hanwoo steers (body weight, 454.3±10.9 kg; age, 14±0.1 month) were allocated into four levels of temperature-humidity index (THI) in a 4×4 Latin square design for 21 days (pre-adaptation, 7 d; heat stress, 7 d; post-adaptation, 7 d) per period. Experimental treatments were assigned according to THI chart based on National Institute Animal Science (NIAS, 2022): Comfort (25.5℃ to 26.5℃, 60%; THI 73 to 75), Mild (28℃ to 29℃, 60%; THI 77 to 79), Moderate (29.5℃ to 30.5℃, 80%; THI 82 to 84), and Severe (31℃ to 32℃, 80%; THI 85 to 86) in separate climatic controlled chambers. Results: The dry matter intake (DMI) of the formula feed was lower in Severe compared to Mild and Comfort (p<0.05). The DMI of rice straw was the lowest in Severe and lower in Moderate than Comfort and Mild (p<0.05). Both average daily gain and feed conversion ratio of Severe and Moderate were lower than those of Mild and Comfort (p<0.05). Water intake was the highest in Severe and lower in Moderate compared with Comfort and Mild (p<0.05). Heart rate and rectal temperature increased as THI level increased (p<0.05). Glucose was the lowest in Severe and lower in Moderate compared to Comfort (p<0.05). On the contrary, non-esterified fatty acid was the highest in Severe and lower in Moderate compared with Comfort (p<0.05). Blood urea nitrogen of Moderate and Severe were higher than those of Comfort and Mild (p<0.05). Cortisol increased as THI increased (p<0.05). Conclusion: This study demonstrated the negative effects of heat stress on the performance and physiological responses of Hanwoo steers during the early-fattening period. In addition, it is judged that the THI chart for Hanwoo steers of National Institute of Animal Science (2022) was properly calculated.

• 한국한의학연구원논문집
• /
• 제12권3호통권18호
• /
• pp.117-130
• /
• 2006

The purpose of this study was to introduce the differential standard of Mok-Hyaeng Radix species. We established the classificatory standard according to the external and internal morphology and the pattern in 4 kinds of Mok-Hyaeng Radix. The results follow: 1. On the external morphology, Radix of Vladimiria souliei had a sticky material in the head of roots and it was yellowish white in the cut surface. It attached to teeth during chewing. Radix of Aucklandia lappa (=Saussurea lappa) was dark grayish brown and was grayish brown in the cut surface. It had special odor and was not attache to teeth chewing it. On the other hand, Radix of Inula helenium was dark brown. In the cut surface, cortical layer was different from wood layer. Radix of Aristolochia contorta was yellowish brown. In the cut surface, it was not smooth and cortical layer was different from wood layer. 2. On the internal morphology, Radix of Vladimiria souliei had many fascicular fibers and scattered large oil chambers in the bast ray, xylem ray, and parenchyma. On Radix of Aucklandia lappa (=Saussurea lappa), it was difficult to find out the trace when the cork layer was exfoliated. The cambium formed circle and the large oil chambers were scattered in the phloem and xylem. On the other hand, external cortical layer of Radix of Inula helenium was detached and cambium was formed to indistinct circle and large oil chambers were scattered in the phloem and xylem. On Radix of Arustolochia contorta, the large oil chambers were scattered in the surface later, bast part was relatively broad and cambium formed circle. 3. On the TLC pattern, Radix of Aristolochia contorta, Inula helenium, Aucklandia lappa, and Vladimiria souliei were chromogenic to violet and purple according to sulfuric acid colour pattern, especially faint on Aristolochia contorta. 4. On the pattern analysis of HPLC, we compared the content and the pattern of constunolide and dehydrocostus lactone, Radix of Aucklandia lappa was similar to Radix of Vladimiria souliei and Radix of Aristolochia contorta was similar to Radix of Inula helenium. On the total HPLC component pattern, constunolide and dehydrocostus lactone were similar in all four types, but it showed the Rf 5-6 peak was only in Radix of Aristolochia contorta, not in Radix of Inula helenium, Aucklandia lappa, and Vladimiria souliei. It is considered the results of this study will be furnished the basis to succeeding studies and it is needed to extensive comparative study for the same genus-degree of relatedness.

• 한국의학물리학회지:의학물리
• /
• 제21권1호
• /
• pp.120-125
• /
• 2010

물흡수선량에 기반한 표준 측정법을 사용하여 흡수선량을 측정 시에 여러 요인들이 크건, 작건, 미미하건 간에 선량 측정의 정확성에 영향을 미칠 수 있다. 이온함의 선질 보정 인자(the beam quality correction factor) ${\kappa}_{Q,Q_0}$ 값 또한 그 중 한 요인이 될 수 있다. 본 연구에서는 특정 이온함 유형(PTW30013, PTW, Germany)을 선정하여, 국내에서 사용하고 있는 기관들로부터 9개의 이온함을 수집하였다. 동일한 전위계와 전기선으로 9개 이온함을 국내 이차표준기관으로부터 교정을 받았다. 이렇게 교정받은 이온함들을 사용하여 Siemens ONCOR 장비의 광자 빔 6 MV와 10 MV 그리고 전자 빔 12 MeV에 대해 기준 조건하에서 흡수선량을 측정하였다. 이온함 간 선량 값의 최대 차이는 광자 빔 6 MV의 경우엔 2.4%, 10MV의 경우에 0.8%, 전자 빔 12 MeV의 경우엔 0.8%이었다. 6 MV에서의 큰 차이는 측정 과정에 문제가 없었다면, 동일한 ${\kappa}_{Q,Q_0}$ 값을 모든 이온함에 적용한 게 한 요인이 될 수 있다. 이는 또한 외부 독립검사가 왜 중요한지를 보여 주는 예라 하겠다.