Two-Layer Model for Open-Channel Flows with Submerged Vegetation

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Numerical Investigations of the Initiation Mechanism of Cellular Secondary Currents in Open-Channel Flows

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Algorithm for 2D Finite Element Modeling of Bed Elevation Change in a Natural River

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Numerical simulations of flow and suspended sediment transport in open-channel flows over smooth-rough bed strips

Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732The flow and transport of suspended sediment in open-channel flows over smooth-rough bed strips were simulated numerically. For the flow, the Reynolds-averaged Navier-Stokes equations were solved with the aid of the Reynolds stress model. Simulated mean flow structures are provided and compared with experimental data available in the literature. The sediment transport of suspended sediment in such flows was also simulated. The transport equation for suspended sediment was solved using the eddy diffusivity concept. The simulation resulted that the sediment concentration changes periodically in the transverse direction, showing higher concentration over the smooth strips. This is consistent with the previous field during the floods. The eddy diffusivity profile was also given and discussed

Satellite Laser Ranging System at Geochang Sta

Korea Astronomy and Space Science Institute (KASI) has been developing the space optical and laser tracking (SOLT) system for space geodesy, space situational awareness, and Korean space missions. The SOLT system comprises satellite laser ranging (SLR), adaptive optics (AO), and debris laser tracking (DLT) systems, which share numerous subsystems, such as an optical telescope and tracking mount. It is designed to be capable of laser ranging up to geosynchronous Earth orbit satellites with a laser retro-reflector array, space objects imaging brighter than magnitude 10, and laser tracking low Earth orbit space debris of uncooperative targets. For the realization of multiple functions in a novel configuration, the SOLT system employs a switching mirror that is installed inside the telescope pedestal and feeds the beam path to each system. The SLR and AO systems have already been established at the Geochang station, whereas the DLT system is currently under development and the AO system is being prepared for testing. In this study, the design and development of the SOLT system are addressed and the SLR data quality is evaluated compared to the International Laser Ranging Service (ILRS) tracking stations in terms of single-shot ranging precision. The analysis results indicate that the SLR system has a good ranging performance, to a few millimeters precision. Therefore, it is expected that the SLR system will not only play an important role as a member of the ILRS tracking network, but also contribute to future Korean space missions

The Management of Cardiovascular Abnormalities in Patient With LEOPARD Syndrome

LEOPARD syndrome (LS) is a rare hereditary disorder in Asian countries. This syndrome consists of multiple systemic abnormalities. In particular, characteristic cardiovascular effects in LS may include variable clinical manifestations from benign to life-threatening courses. The cardiac effects of this syndrome consist of left ventricular hypertrophy (LVH), pulmonary stenosis (PS), coronary artery dilatation and electrocardiogram(ECG) abnormalities. Since there are few LS patients who have undergone a complete cardiovascular evaluation, the nature and clinical prognosis of cardiovascular abnormalities in this syndrome remain uncertain. Also, there have been few reports on therapeutic strategies for cardiovascular abnormalities in LS. Here we describe a case of LS who presented with multiple cardiovascular problems and underwent successful surgical and medical treatment

Consecutive Macular Edema and Visual Outcome in Branch Retinal Vein Occlusion

Purposes. The study introduced the concept of “consecutive macular edema” and evaluated the validity of visual outcome in macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Methods. Patients were categorized into the gainer group and the nongainer group according to the final visual acuity. We analyzed clinical characteristics involving total and consecutive duration of ME between the two groups. Results. Among the total 71 eyes of 71 patients, intravitreal bevacizumab injection (26 patients), triamcinolone (21), and natural course (33) were enrolled. The consecutive duration of ME was shorter in the gainer group than in the nongainer group (3.33 ± 1.50 and 5.24 ± 2.39 months; P=0.000). After exclusion of macular ischemia, consecutive duration of ME in gainer group was also significantly shorter than in nongainer group (3.62 ± 1.60 and 6.11 ± 4.20 months; P=0.010). Conclusions. The duration of ME in the nongainer group was longer than in the gainer group. In particular, the consecutive duration was an important factor in determining the final visual outcome. Clinical Trial Registration. Approval by Hallym University Sacred Heart Hospital Institutional Review Board/Ethics Committee was obtained for this retrospective study

Evaluation of a Laser Altimeter using the Pseudo-Random Noise Modulation Technique for Apophis Mission

Apophis is a near-Earth object with a diameter of approximately 340 m, which will come closer to the Earth than a geostationary orbit in 2029, offering a unique opportunity for characterizing the object during the upcoming encounter. Therefore, Korea Astronomy and Space Science Institute has a plan to propose a space mission to explore the Apophis asteroid using scientific instruments such as a laser altimeter. In this study, we evaluate the performance metrics of a laser altimeter using a pseudorandom noise modulation technique for the Apophis mission, in terms of detection probability and ranging accuracy. The closed-form expression of detection probability is provided using the cross correlation between the received pulse trains and pseudo-random binary sequence. And the new ranging accuracy model using Gaussian error propagation is also derived by considering the sampling rate. The operation range is significantly limited by thermal noise rather than background noise, owing to not only the low power laser but also the avalanche photodiode in the analog mode operation. However, it is demonstrated from the numerical simulation that the laser altimeter can achieve the ranging performance required for a proximity operation mode, which employs commercially available components onboard CubeSat-scale satellites for optical communications