• 한국농공학회논문집
• /
• 제55권6호
• /
• pp.145-154
• /
• 2013

Recently, damage occurrence by wind erosion has been increasing in society. In times past, such problems only took place in desert area ; however, in recent years, the wind erosion problem is spreading out to agricultural land. Wind erosion in agricultural land can cause loss of loam soils, the disturbance of the photosynthesis of the crop fields and serious economic losses. To overcome the mentioned problems, installation of windbreak fence can be recommended which function as disturbing strong wind and wind erosion. However, there is still no proper guideline to install the windbreak fence and the installation used to rely on the intuition of the workers due to the lack of related studies. Therefore, this study measured the aerodynamic resistance of screens of the windbreak fence using the apparatus for testing screens. The apparatus for testing screens was designed to measure pressure loss around the screen. Measured pressure loss by wall friction compensated for pressure loss to calculate the aerodynamic resistance of screens. The result of pressure loss by regression analysis derived the aerodynamic coefficient of Darcy-Forchheimer equation and power law equation. The aerodynamic resistance was constant regardless of the overlapped shape when the screen was overlapped into several layers. Increasing the number of layers of the screen, internal resistance increased significantly more, and pressure loss caused by the screen also increased linearly when the wind speed was certain conditions, but permeability had no tendency. In the future, the results of this study will be applied to the computational fluid dynamics simulation. The simulation models will be also validated in advance by wind tunnel experiments. It will provide standard of a design for constructing windbreak fence.

• The Korean Journal of Pain
• /
• 제22권3호
• /
• pp.241-244
• /
• 2009

Retrobulbar hematoma can arise from orbital trauma and periorbital or intraorbital procedures, and it can result in several morbidities including vision loss. Making the immediate diagnosis and performing decompression of the retrobulbar hematoma are crucial for preventing serious morbidities such as permanent vision loss. We present here a case of temporary vision loss that was due to iatrogenic retrobulbar hematoma in a patient who received infraorbital nerve block for the treatment of trigeminal neuralgia. A 70-year-old woman with trigeminal neuralgia was treated with infraorbital nerve block. Just after the procedure she experienced acute periorbital swelling, proptosis and worsening visual acuity. Immediate orbital computed tomography was done, and this revealed a retrobulbar hematoma. The patient underwent lateral canthotomy with cantholysis and administration of dexamethasone and mannitol. Improvement of visual acuity began 3 hours after these procedures. Her visual acuity was greatly improved 12 days after admission.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제16권3호
• /
• pp.428-437
• /
• 1994

Optic nerve injury serious enough to result in blindness had been reported to occur in 3% of facial fractures. When blindness is immediate and complete, the prognosis for even partial recovery is poor. Progressive or incomplete visual loss may be ameliorated either by large dosage of steroid or by emergency optic nerve decompression, depending on the mechanism of injury, the degree of trauma to the optic canal, and the period of time that elapses between injury and medical intervention. We often miss initial assessment of visual function in management of facial fracture patients due to loss of consciousness, periorbital swelling and emergency situations. Delayed treatment of injuried optic nerve cause permanent blindness due to irreversible change of optic nerve. But by treating posttraumatic optic nerve injuries aggressively, usable vision can preserved in a number of patients. The following report concerns three who suffered visual loss due to optic nerve injury with no improvement after steroid therapy and/or optic nerve decompression surgery.

• 한국지반환경공학회 논문집
• /
• 제18권1호
• /
• pp.37-47
• /
• 2017

The Mekong River plays an extremely important role in Southeast Asia. Flowing through six countries, including China, Myanmar, Thailand, Laos PDR, Cambodia, and Vietnam, it is a site of great biological and ecological diversity and the habitat of numerous species of fish. It also supports a very large population that lives along the river basin. Therefore, much attention has been focused on the giant Mekong River Basin, particularly, its soil erosion and sedimentation problems. In fact, many methods have been used to calculate and simulate these problems. However, in the case of the Mekong River Basin, the available data is limited because of the extreme size of the area (about $795,000km^2$) and lack of equipment systems in the countries through which the Mekong River flows. In this study, we applied the Universal Soil Loss Equation (USLE) model in a GIS (Geographic Information System) framework to calculate the amount of soil erosion and sediment load during the selected period, from 1951 to 2007. The result points out dangerous areas, such as the Upper Mekong River Basin and 3S Basin (containing the Sekong, Sesan, and Srepok Rivers) that are suffering the serious consequences of soil erosion problems. Moreover, the present model is also useful for supporting river basin management in the implementation of sustainable management practices in the Mekong River Basin and other basins.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
• /
• pp.373-378
• /
• 2000

The crevice corrosion of local corrosion occur when the gap exist on metal surface. This crevice corrosion happen to region such as flange of pipe, contact part of casing, under gasket and packing, between valve disk and seat of pump etc. Especially The crevice corrosion of mild steel(SS 400) get serious. This paper was studied on the crevice corrosion of SS 400 in fluid environment. In $0\%,\;2\%,\;3.5\%,\;5\% NaCl$ solution, the aspect of the crevice corrosion and polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 with crevice and non-crevice was measured according to the NaCl concentration. The main results obtained are as follows : 1) Under crevice corrosion, the corrosion potential become less noble as the concentration of NaCl solution increased. 2) The current density under open circuit potential was high drained as concentration of NaCl solution increased by $3.5\%$ but the concentration increased over $3.5\%$, the current density was low drained. 3) The weight loss rate of SS 400 was increased as concentration of NaCl solution Increased by $3.5\%$, but the concentration increased over $3.5\%$, that of SS 400 was decreased. 4) Effect of oxygen for crevice corrosion in the concentration of $3.5\%$ NaCl solution become sensitive than that $0\%$ NaCl solution.

• 한국환경보건학회지
• /
• 제21권4호
• /
• pp.56-62
• /
• 1995

Recently, the traffic noise around residences and schools has become a serious social problem with the increase of the amount of transportation. This study was performed to investigate the sound proof efficiency of windows for traffic noise. The results were as follows 1) The traffic noise in 19 sites among 22 sampling sites was higher value than 65 dB(A) being roadside environment standard level in the daytime when all windows were opened, while the noise in 22 sampling sites was transmitted below standard level when all windows were closed. 2) The transmission loss of sound level at single window and double windows were 10~25 dB(A) and 11~29 dB(A) respectively. 3) The transmission loss of sound level at sampled school with sound proof pannel was 7~8 dB (A), which was lower 2~7 dB(A) than the theoretical value of the influence assessment . 4) The construction cost of double windows was lower 28% even if include the cost of setting up air conditioner for the summer season and the power consuming cost for its operation than that of sound proof pannel for traffic noise. 5) The effect of transmission loss of windows was more influenced by airtight than materials of windows.

• 무역상무연구
• /
• 제59권
• /
• pp.113-135
• /
• 2013

Piracy has been an ongoing and serious problem in international shipping industry. Somalia is often in the news these days. Somalia has been in a state of unrest for more than two centuries. In recent times, the situation has remained unstable. The persistent unrest is the major driver behind the piracy epidemic in Somalia waters. By the MIA 1906, s.78(1), the expenses in order to be recoverable must have been "properly incurred". The underwriter is also liable in certain circumstances for expenses incurred by the assured in an attempt to avert or diminish loss covered by the policy, under provisions. This class of expenditure is commonly referred to as sue and labour expenses, or suing and labouring expenses; less commonly, as particular charges. The standard marine policy(the S.G.Form) contained what was invariably called the sue and labour clause, which has been replaced in the current Institute Clauses by the "Duty of Assured(Sue and Labour)" Clause in the Hull Clauses, and the "Duty of Assured" Clause, headed "Minimizing losses", in the Cargo Clauses. Sue and labour charges are not confined to expenditure on the part of the assured and his agents, but can include quantified loss consequent upon a sacrifice properly and reasonably made to avert or minimize an insured loss.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
• /
• pp.327-328
• /
• 2006

In generally, under the influence of over-pressure drop, serious problems such as cavitation, choked flow, flashing and vibration has been coming around the tilting disk check valve. A PIV experiment to examine the cause of energy loss has been performed and the improvement configuration of valve seat based on this visualization results is proposed. In the visualization results, flows in the piping system became instability under the influence of the shape of boss. This unstable flows induces sudden pressure drop in the piping system. So, we change the configuration of boss as a streamlined design to be stabilized the flows. A pressure measurement has been performed to know that the influence of the configuration change. In result, the rate of pressure loss reduction is about 22% at the position of No. 2 and 24.2% at the position of No. 6 in comparison with pre-improved shape.

• 한방비만학회지
• /
• 제7권1호
• /
• pp.1-7
• /
• 2007

Background : Use of Ma Huang is controversial. Multiple reports of adverse effects led the U.S. Federal Drug Administration (FDA) to announce about prohibiting dietary supplements containing ephedrine alkaloids/Ma Huang. Objective : The objective of the study was to review the evidence from literature and rigorous clinical trials on the dosage, effectiveness, and adverse effects. Methods : Literature searches were conducted in U.S. FDA database after 2003 and digital Uibujeonok(醫部全錄). Hand searches of medical journal and bibliographies of identified articles were conducted. Results : Ma Huang has been used in Korean Oriental Medicine to treatment asthma and other ailments. Recently, Ephedrine/Ma Huang are used for weight loss or to enhance athletic performance in Europe and America, Korea. Ephedrine/Ma Huang are associated with increased risk of psychiatric, autonomic, or gastrointestinal symptoms, and heart palpitations. In addition to that, a risk of serious adverse events, including heart attack, stroke, epilepsy and psychiatric problem are also have been reported. Therefore, max dose of total alkaloids of ephedrine is studied in need of a specialist's part. Conclusion : In most reports, Ma Huang effectively promoted short-term weight loss and enhancement of athletic performance, But, safety with long-term use requires further investigation.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
• /
• pp.115-118
• /
• 2005

상수도관망에서 발생하는 누수현상은 수자원의 손실뿐만 아니라 압력손실로 인한 추가적 가압 설비의 필요성 및 누수되는 관로 주변의 토질의 약화 등을 초래하여 관망의 유지관리를 어렵게 하고, 심각한 경제적 손실을 야기하고 있다. 이에 구역고립으로 인한 수압과 유량 등을 상시 모니터링하여 누수사고의 적극적인 대처와 누수발생을 미연에 방지함으로써 유수율을 향상 시킬 수 있다 .실제 구역고립 후 계속되는 수압 조절 및 유입유량의 모니터링으로 인하여 구역내 유수율 산정결과 평균 유수율은 88.94%로서 부산광역시 2003년도의 유수율 79.5%보다 9.44% 높게 조사되었다.