• Title/Summary/Keyword: Natural Shedding

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Modeling of Fine Sediment Transport under Multiple Breakwaters of Surface-Piercing Type

  • Lee, J. L.;Oh, M. R.
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.557-562
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    • 2004
  • A surface-piercing barrier model is presented for understanding morphological development in the sheltered region and investigating the main factors causing the severe accumulation. Surface-piercing structures like vertical barriers, surface docks and floating breakwaters are recently favored from the point of view of a marine scenario since they do not in general partition the natural sea. The numerical solutions are compared with experimental data on wave profiles and morphological change rates within a rectangular harbor of a constant depth protected by surface-piercing thin breakwaters as a simplified problem. Our numerical study involves several modules: 1) wave dynamics analyzed by a plane-wave approximation, 2) suspended sediment transport combined with sediment erosion-deposition model, and 3) concurrent morphological changes. Scattering waves are solved by using a plane wave method without inclusion of evanescent modes. Evanescent modes are only considered in predicting the reflection ratio against the vertical barrier and energy losses due to vortex shedding from the lower edge of plate are taken into account. A new relationship to relate the near-bed concentration to the depth-mean concentration is presented by analyzing the vertical structure of concentration. The numerical solutions were also compared with experimental data on morphological changes within a rectangular harbor of constant water depth. Through the numerical experiments, the vortex-induced flow appears to be not ignorable in predicting the morphological changes although the immersion depth of a plate is not deep.

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Effects of coupled translational-torsional motion and eccentricity between centre of mass and centre of stiffness on wind-excited tall buildings

  • Thepmongkorn, S.;Kwok, K.C.S.
    • Wind and Structures
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    • v.5 no.1
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    • pp.61-80
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    • 2002
  • Wind tunnel aeroelastic model tests of the Commonwealth Advisory Aeronautical Research Council (CAARC) standard tall building were conducted using a three-degree-of-freedom base hinged aeroelastic(BHA) model. Experimental investigation into the effects of coupled translational-torsional motion, cross-wind/torsional frequency ratio and eccentricity between centre of mass and centre of stiffness on the wind-induced response characteristics and wind excitation mechanisms was carried out. The wind tunnel test results highlight the significant effects of coupled translational-torsional motion, and eccentricity between centre of mass and centre of stiffness, on both the normalised along-wind and cross-wind acceleration responses for reduced wind velocities ranging from 4 to 20. Coupled translational-torsional motion and eccentricity between centre of mass and centre of stiffness also have significant impacts on the amplitude-dependent effect caused by the vortex resonant process, and the transfer of vibrational energy between the along-wind and cross-wind directions. These resulted in either an increase or decrease of each response component, in particular at reduced wind velocities close to a critical value of 10. In addition, the contribution of vibrational energy from the torsional motion to the cross-wind response of the building model can be greatly amplified by the effect of resonance between the vortex shedding frequency and the torsional natural frequency of the building model.

Vehicle-induced aerodynamic loads on highway sound barriers part 2: numerical and theoretical investigation

  • Wang, Dalei;Wang, Benjin;Chen, Airong
    • Wind and Structures
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    • v.17 no.5
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    • pp.479-494
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    • 2013
  • The vehicle-induced aerodynamic loads bring vibrations to some of the highway sound barriers, for they are designed in consideration of natural wind loads only. As references to the previous field experiment, the vehicle-induced aerodynamic loads is investigated by numerical and theoretical methodologies. The numerical results are compared to the experimental one and proved to be available. By analyzing the flow field achieved in the numerical simulation, the potential flow is proved to be the main source of both head and wake impact, so the theoretical model is also validated. The results from the two methodologies show that the shorter vehicle length would produce larger negative pressure peak as the head impact and wake impact overlapping with each other, and together with the fast speed, it would lead to a wake without vortex shedding, which makes the potential hypothesis more accurate. It also proves the expectation in vehicle-induced aerodynamic loads on Highway Sound Barriers Part1: Field Experiment, that max/min pressure is proportional to the square of vehicle speed and inverse square of separation distance.

A Bibliometric Comparative Analysis on the Applications of AI, IoT, and Big Data to Energy Efficiency

  • Yong Sauk Hau
    • International Journal of Internet, Broadcasting and Communication
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    • v.16 no.1
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    • pp.287-296
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    • 2024
  • Artificial intelligence (AI), the Internet of Things (IoT), and Big Data are playing important roles in improving or upgrading energy efficiency. Furthermore, their roles in energy efficiency are expected to become more and more essential. This study conducted a bibliometric comparative analysis on the features in the articles on the AI, the IoT, and the Big Data in energy efficiency by using the Web of Science database and compared the features in their trends in article publications, citations, countries, research areas, journals, and funding agencies from 2012 to 2022. This study attempted to make significant contributions by shedding new light on the following features. Among the AI, the IoT, and the Big Data in energy efficiency, the most articles were published and the most article citations were received in the AI in energy efficiency. China was found out to be the most leading country. Engineering and computer science were revealed to be the first research area. IEEE Access and IEEE Internet of Things were ranked with first journal. National Natural Science Foundation of China was the first research funding agency concerning the articles published in the AI, the IoT, and the Big Data in energy efficiency from 2012 to 2022.

Innate Type-2 Cytokines: From Immune Regulation to Therapeutic Targets

  • Hye Young Kim;Dongjin Jeong;Ji Hyung Kim;Doo Hyun Chung
    • IMMUNE NETWORK
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    • v.24 no.1
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    • pp.6.1-6.17
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    • 2024
  • The intricate role of innate type-2 cytokines in immune responses is increasingly acknowledged for its dual nature, encompassing both protective and pathogenic dimensions. Ranging from defense against parasitic infections to contributing to inflammatory diseases like asthma, fibrosis, and obesity, these cytokines intricately engage with various innate immune cells. This review meticulously explores the cellular origins of innate type-2 cytokines and their intricate interactions, shedding light on factors that amplify the innate type-2 response, including TSLP, IL-25, and IL-33. Recent advancements in therapeutic strategies, specifically the utilization of biologics targeting pivotal cytokines (IL-4, IL-5, and IL-13), are discussed, offering insights into both challenges and opportunities. Acknowledging the pivotal role of innate type-2 cytokines in orchestrating immune responses positions them as promising therapeutic targets. The evolving landscape of research and development in this field not only propels immunological knowledge forward but also holds the promise of more effective treatments in the future.

Lambs Infected with UV-Attenuated Sporocysts of Sarcocystis ovicanis Produced Abnormal Sarcocysts and Induced Protective Immunity against a Challenge Infection

  • Abdel-Baki, Abdel-Azeem;Allam, Gamal;Sakran, Thabet;El-Malah, El-Mahy
    • Parasites, Hosts and Diseases
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    • v.47 no.2
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    • pp.131-138
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    • 2009
  • The present study surveyed the prevalence of natural infection of the sheep esphagus muscle with sarcocysts of Sarcocystis ovicanis and examined induction of protective immunity using UV-attenuated sporocysts. The overall prevalence of natural infection of the sheep was 95%. Infectivity of the collected sarcocysts was confirmed by shedding of sporulated oocysts after feeding infected esophageal tissues to dogs. To induce protective immunity, lambs were immunized 3 times (once a week) with $1.5{\times}10^4$ sporocysts exposed to UV-light for 30min (UV-30 group) or 60 (UV-60 group) min and then challenged with $1.5{\times}10^4$ normal sporocysts at the 3rd week post the 1st vaccination. These lambs showed high survival and less clinical signs of sarcocystosis than normal infected lambs. The attenuated sporocysts produced abnormal cysts; small in size and detached from the muscle fiber. These abnormalities were more obvious in UV-60 group than UV-30 group. Also, the $IFN-{\gamma}$ level and lymphocyte percentage were increased while the total leukocyte count was decreased in the UV-60 group compared with other groups. The high level of $IFN-{\gamma}$ may be an evidence for the induction of Th1 responses which may have protective effect against a challenge infection.

Finite Element Dynamic Analysis of a Vertical Pile by Wave and Tidal Current (파도와 조류에 의한 수직 파일의 유한요소 동적거동 해석)

  • 박문식
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.2
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    • pp.183-192
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    • 2004
  • New dynamic analysis procedures lot the vertically drilled sea water pile are suggested and demonstrated by the typical design Problem. Pile structure submerged in the sea water as well as forces by the ocean waves and tidal currents are modeled and formulated by finite element method. To obtain wave forces for the finite element equation, Airy's wave theory is tested and selected among others. Lateral lifting forces induced by the vortex shedding of current flow is simply based on the harmonic function with the Strouhal frequency and lifting coefficient. Natural frequencies and frequency responses for the pile are calculated by NASTRAN using the results of the formulation. Dynamic displacement and stress results obtained by these procedures are shown to be applicable to predict the dynamic behaviors of the ocean pile by the wave and lifting forces as a preliminary design analysis.

Inference of the Conceptual Model of Wild Gardens - A Comparative Study of William Robinson and Gertrude Jekyll - (와일드 가든(Wild Garden)의 개념적 모형 유추 - 윌리암 로빈슨(William Robinson)과 거투르드 제킬(Gertrude Jekyll)의 비교 연구 -)

  • Park, Eun-Yeong;Yoon, Sang-Jun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.31 no.4
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    • pp.62-69
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    • 2013
  • The origin of natural planting, which is getting the spotlight in modern time facing natural and environmental problems, can be found from wild gardens. They were started by William Robinson and concretely embodied by Gertrude Jekyll. It is worth shedding new light on wild gardens, as they served as a pathbreaker for ecological design and an important foundation for the specialization of naturalism, which are part of the most important topics in modern gardens. This study aimed to infer the conceptual model of wild gardens and identify their historic significance by comparatively analyzing Robinson's Gravetye Manor and Jekyll's Munstead Wood. The results are: Firstly, they inherited inspirations for spatial organization from basic cottage gardens and introduced informal forms. Secondly, in terms of the use of materials, they had observed various climates in their journeys so that they could use both native and naturalized plants based on their understanding of the plants' hardiness and exotic species. They also displayed interests in plants in the woodlands and forests. Thirdly, in terms of design techniques, they investigated the colors and textures of individual plants and their relationships to produce a variety of views that resembled nature in microcosm. Fourthly, in terms of maintenance, their basic orientation was the minimum maintenance to allow plants to live according to their nature.

The Reproductive Patterns and Clinical Application of Endangered Common Chimpanzees by Monitoring the Steroid Hormone Measurements in Fecal Samples (분변내 스테로이드 호르몬의 측정을 통한 멸종 위기 침팬지의 번식형태와 임상적용)

  • Jung, So-Young;Kim, Mi-Young;Jeong, Yu-Jeong;Jang, Yu-Ni;Lim, Yang-Mook;Yoon, Yong-Dal
    • Development and Reproduction
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    • v.15 no.2
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    • pp.167-172
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    • 2011
  • To monitor the reproductive patterns of endangered common chimpanzee including annual reproductive cycle, amenorrhea, breeding season, and pregnancy diagnosis, Time-Resolved Fluorescence Immuno Assay (TR-FIA) was used to trace MRH (estradiol, progesterone, testosterone) and human chorionic gonadotropin (HCG). In result of this research, age was not the important factor in determining the reproduction capability in common chimpanzee; it was rather greatly influenced by the combination of various factors such as individual's fertilizing ability, presence of obstetrical diseases, the pattern of mating behavior, and the mental communication under the introduction of a mating partner. This research will play an important role in operating conservation project for common chimpanzees and can be extended also for shedding new light on understanding human menopause and obstetrical diseases.

A Study of Channel Migration in Alluvial River (충적하천의 유로이동에 관한 연구)

  • Roh, Sub;Chung, Yong Tai;Song, Jai Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.5
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    • pp.173-181
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    • 1993
  • Under natural conditions, rivers do not in general take straight courses but instead take winding courses. This is known as meandering of rivers. Meandering of rivers are so complicated because of the mutual interactions between flow and movable boundaries. In quantitative information, it is important to predict the future location of a river channel(channel migration) because in selecting a bridge site or a location of a road. It may be valuable to know the future impact of a nearby river on those structures. When the prediction model of the migration of channel is used in domestic rivers with high coefficient of river regime, it is rational to use the periodical dominant discharge (PDD), which is named firstly by the author, instead of the average discharge. According to the analysis of the erosion coefficient, the mean deviation on the channel migration, and the bed scour factor, it can bring shedding light on the fact that the discharge is one of the dominant components in channel migration. In project area, the discharge that can shift the channel is slightly greater than 6,000CMS. The prediction model of the migration of channel estimated the erosion coefficient, $E_0$ by the data from the South Han River. This estimated value from the South Han River was also used to predict the migration of the South Han River in year 2000.

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