• Title/Summary/Keyword: the influence of wind

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The Influence of Seasons and Weather on the Volume of Trauma Patients: 4 Years of Experience at a Single Regional Trauma Center

  • Kim, Se Heon;Sul, Young Hoon;Lee, Jin Young;Kim, Joong Suck
    • Journal of Trauma and Injury
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    • v.34 no.1
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    • pp.21-30
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    • 2021
  • Purpose: The purpose of this study was to determine the influence of seasons and weather on the volume of trauma patients in central Korea. Methods: The records of 4,665 patients treated at Chungbuk National Hospital Regional Trauma Center from January 2016 to December 2019 were retrospectively reviewed. Meteorological data including hourly temperature (℃), precipitation (mm), humidity (%), and wind speed (m/s) for each district were collected retrospectively. Statistical analysis was done using the independent t-test, one-way analysis of variance (ANOVA), and linear regression analysis. Results: Patients' average age was 53.66 years, with a significant difference between men (49.92 years) and women (60.48 years) (p<0.001). Rolling/slipping down was a prominent cause of injury in winter (28.4%, n=283), with statistical significance (p<0.001). Trauma occurred least frequently in winter (p=0.005). Linear regression analysis revealed an increasing number of patients as the temperature increased (p<0.05), the humidity increased (p<0.001), and the wind speed decreased (p<0.001). Precipitation did not affect patient volume (p=0.562). One-way ANOVA revealed a decreased incidence of trauma when the temperature exceeded 30℃ (p<0.001), and when the humidity was more than 75%, compared to 25-50% and 50-75%. Conclusions: At the regional trauma center of Chungbuk National University Hospital, in central Korea, the number of trauma patients was lowest in winter, and patient volume was affected by temperature, humidity, and wind speed.

Variation in the Pullout Capacity according to the Tilt and Misorientation of a Floating Offshore Wind Turbine Suction Anchor Using Geometric Method (기하학적 방법을 이용한 부유식 해상풍력 석션앵커의 수직도와 회전오차에 따른 인발지지력 변화)

  • Dae-Hwan Kim;Na-Young Jung;Won-Hyo Lee;Tae-Hyung Kim
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.36 no.3
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    • pp.95-104
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    • 2024
  • In this study, geometric calculation was performed to investigate the influence of the combined effect of tilt and misorientation on the pullout capacity of suction anchor used in floating offshore wind turbine. When considering the combined effect of tilt and misorientation, it was observed that they do not proportionally affect the pullout capacity but rather influence each other relatively. Criteria considering both tilt and misorientation are not provided in existing literature or DNV recommendation. Therefore, based on the comprehensive results of this study, a proposed decrease in pullout capacity within 3% is suggested.

A Study on the Influence of Aerological Observation Data Assimilation at Honam Area on Numerical Weather Prediction (호남지방 고층관측자료동화가 수치기상예보에 미치는 영향에 관한 연구)

  • Ryu Chan-Su;Won Hyo-Sung;Lee Soon-Hwan
    • Journal of the Korean earth science society
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    • v.26 no.1
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    • pp.66-77
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    • 2005
  • Aerological observation at Heuksando located in south-western part of Koran Peninsula has been started at 1 June 2003. In order to clarify the improvement of meteorological prediction quality. it is necessary to compare between aerological data observed at Gawngju and Heuksando and to make clear the influence of Heuksando data assimilation. Therefore numerical simulations were carried out with High resolution meterological prediction system based on MM5(The 5th Generation Mesoscale Model). The pattern of wind and temperature field observed at Heuksando and Gwangju are different due to land surface friction End Sensible heat flux at surface and the wind field Simulated With Gwangju and Heuksando aerological data agree well with observation wind field. Although the amount of precipitation in these experiments is underestimated. the area and starting time of precipitation around Honam province in case with Heuksando data is more reliable that without the data.

An improved extended Kalman filter for parameters and loads identification without collocated measurements

  • Jia He;Mengchen Qi;Zhuohui Tong;Xugang Hua;Zhengqing Chen
    • Smart Structures and Systems
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    • v.31 no.2
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    • pp.131-140
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    • 2023
  • As well-known, the extended Kalman filter (EKF) is a powerful tool for parameter identification with limited measurements. However, traditional EKF is not applicable when the external excitation is unknown. By using least-squares estimation (LSE) for force identification, an EKF with unknown input (EKF-UI) approach was recently proposed by the authors. In this approach, to ensure the influence matrix be of full column rank, the sensors have to be deployed at all the degrees-of-freedom (DOFs) corresponding to the unknown excitation, saying collocated measurements are required. However, it is not easy to guarantee that the sensors can be installed at all these locations. To circumvent this limitation, based on the idea of first-order-holder discretization (FOHD), an improved EKF with unknown input (IEKF-UI) approach is proposed in this study for the simultaneous identification of structural parameters and unknown excitation. By using projection matrix, an improved observation equation is obtained. Few displacement measurements are fused into the observation equation to avoid the so-called low-frequency drift. To avoid the ill-conditioning problem for force identification without collocated measurements, the idea of FOHD is employed. The recursive solution of the structural states and unknown loads is then analytically derived. The effectiveness of the proposed approach is validated via several numerical examples. Results show that the proposed approach is capable of satisfactorily identifying the parameters of linear and nonlinear structures and the unknown excitation applied to them.

The Concept of Wind in Traditional Chinese Medicine

  • Dashtdar, Mehrab;Dashtdar, Mohammad Reza;Dashtdar, Babak;Kardi, Karima;Shirazi, Mohammad khabaz
    • Journal of Pharmacopuncture
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    • v.19 no.4
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    • pp.293-302
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    • 2016
  • The use of folk medicine has been widely embraced in many developed countries under the name of traditional, complementary and alternative medicine (TCAM) and is now becoming the mainstream in the UK and the rest of Europe, as well as in North America and Australia. Diversity, easy accessibility, broad continuity, relatively low cost, base levels of technological inputs, fewer side effects, and growing economic importance are some of the positive features of folk medicine. In this framework, a critical need exists to introduce the practice of folk medicine into public healthcare if the goal of reformed access to healthcare facilities is to be achieved. The amount of information available to public health practitioners about traditional medicine concepts and the utilization of that information are inadequate and pose many problems for the delivery of primary healthcare globally. Different societies have evolved various forms of indigenous perceptions that are captured under the broad concept of folk medicine, e.g., Persian, Chinese, Grecian, and African folk medicines, which explain the lack of universally accepted definitions of terms. Thus, the exchange of information on the diverse forms of folk medicine needs to be facilitated. Various concepts of Wind are found in books on traditional medicine, and many of those go beyond the boundaries established in old manuscripts and are not easily understood. This study intends to provide information, context, and guidance for the collection of all important information on the different concepts of Wind and for their simplification. This new vision for understanding earlier Chinese medicine will benefit public health specialists, traditional and complementary medicine practitioners, and those who are interested in historical medicine by providing a theoretical basis for the traditional medicines and the acupuncture that is used to eliminate Wind in order to treat various diseases.

Tropical Night (Nocturnal Thermal High) in the Mountainous Coastal City

  • Choi, Hyo
    • Journal of Environmental Science International
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    • v.13 no.11
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    • pp.965-985
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    • 2004
  • The investigation of driving mechanism for the formation of tropical night in the coastal region, defined as persistent high air temperature over than 25$^{\circ}C$ at night was carried out from August 14 through 15, 1995. Convective boundary layer (CBL) of a 1 km depth with big turbulent vertical diffusion coefficients is developed over the ground surface of the inland basin in the west of the mountain and near the top of the mountain, while a depth of thermal internal boundary layer (TIBL) like CBL shrunken by relatively cool sea breeze starting at 100 km off the eastern sea is less than 150 m from the coast along the eastern slope of the mountain. The TIBL extends up to the height of 1500 m parallel to upslope wind combined with valley wind and easterly sea breeze from the sea. As sensible heat flux convergences between the surface and lower atmosphere both at the top of mountain and the inland coast are much greater than on the coastal sea, sensible heat flux should be accumulated inside both the TIBL and the CBL near the mountain top and then, accumulated sensible heat flux under the influence of sea breeze circulation combined with easterly sea breeze from sea to inland and uplifted valley wind from inland to the mountain top returning down toward the eastern coastal sea surface should be transported into the coast, resulting in high air temperatures near the coastal inland. Under nighttime cooling of ground surface after sunset, mountain wind causes the daytime existed westerly wind to be an intensified westerly downslope wind and land breeze further induces it to be strong offshore wind. No sensible heat flux divergence or very small flux divergence occurs in the coast, but the flux divergences are much greater on the top of the mountain and along its eastern slope than on the coastal inland and sea surfaces. Thus, less cooling down of the coastal surface than the mountain surface and sensible heat transfer from warm pool over the coast into the coastal surface produce nocturnal high air temperature on the coastal inland surfaces, which is not much changed from daytime ones, resulting in the persistence of tropical night (nocturnal thermal high) until the early in the morning.

Modeling the long-term vegetation dynamics of a backbarrier salt marsh in the Danish Wadden Sea

  • Daehyun Kim
    • Journal of Ecology and Environment
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    • v.47 no.2
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    • pp.49-62
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    • 2023
  • Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

Numerical and experimental study of unsteady wind loads on panels of a radar aerial

  • Scarabino, Ana;Sainz, Mariano Garcia;Bacchi, Federico;Delnero, J. Sebastian;Canchero, Andres
    • Wind and Structures
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    • v.23 no.1
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    • pp.1-18
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    • 2016
  • This work experimentally and numerically analyzes the flow configurations and the dynamic wind loads on panels of rectangular L/h 5:1 cross section mounted on a structural frame of rectangular bars of L/h 0.5:1, corresponding to a radar structure. The fluid dynamic interaction between panels and frame wakes imposes dynamic loads on the panels, with particular frequencies and Strouhal numbers, different from those of isolated elements. The numerical scheme is validated by comparison with mean forces and velocity spectra of a panel wake obtained by wind tunnel tests. The flow configuration is analyzed through images of the numerical simulations. For a large number of panels, as in the radar array, their wakes couple in either phase or counter-phase configurations, changing the resultant forces on each panel. Instantaneous normal and tangential force coefficients are reported; their spectra show two distinct peaks, caused by the interaction of the wakes. Finally, a scaled model of a rectangular structure comprised of panels and frame elements is tested in the boundary layer wind tunnel in order to determine the influence of the velocity variation with height and the three-dimensionality of the bulk flow around the structure. Results show that the unsteady aerodynamic loads, being strongly influenced by the vortex shedding of the supporting elements and by the global 3-D geometry of the array, differ considerably on a panel in this array from loads acting on an isolated panel, not only in magnitude, but also in frequency.

Development of an Infiltration and Ventilation Model for Predicting Airflow Rates within Buildings (빌딩 내의 공기유동량 예측을 위한 누입 및 환기모델의 개발)

  • Cho, Seok-Ho
    • Journal of Environmental Science International
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    • v.23 no.2
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    • pp.207-218
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    • 2014
  • A ventilation model was developed for predicting the air change per hour(ACH) in buildings and the airflow rates between zones of a multi-room building. In this model, the important parameters used in the calculation of airflow are wind velocity, wind direction, terrain effect, shielding effect by surrounding buildings, the effect of the window type and insect screening, etc. Also, the resulting set of mass balance equations required for the process of calculation of airflow rates are solved using a Conte-De Boor method. When this model was applied to the building which had been tested by Chandra et al.(1983), the comparison of predicted results by this study with measured results by Chandra et al. indicated that their variations were within -10%~+12%. Also, this model was applied to a building with five zones. As a result, when the wind velocity and direction did not change, terrain characteristics influenced the largest and window types influenced the least on building ventilation among terrain characteristics, local shieldings, and window types. Except for easterly and westerly winds, the ACH increased depending on wind velocity. The wind direction had influence on the airflow rates and directions through openings in building. Thus, this model can be available for predicting the airflow rates within buildings, and the results of this study can be useful for the quantification of airflow that is essential to the research of indoor air quality(temperature, humidity, or contaminant concentration) as well as to the design of building with high energy efficiency.

China's Wind Energy Development and the Socio-political Conditions for Energy Transition: Focusing on Norm Promotions by Transnational Actors (중국 풍력발전 사례를 통한 에너지전환의 정치사회적 조건 연구: 초국가 행위자의 규범확산 활동을 중심으로)

  • Kyu Youn Choi
    • The Journal of Learner-Centered Curriculum and Instruction (JLCCI)
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    • v.23 no.1
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    • pp.197-241
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    • 2019
  • The rapid development of China's wind energy sector was facilitated by a number of transnational actors including organisations for international cooperation and international environmental organisations. This paper explores their evolving roles at different development stages in order to extend our understanding of the socio-political conditions for energy transition. Employing the framework of norm diffusion theories, this study focuses on the transnational advocacy group supporting wind energy for environmental purposes and analyses their norm promotion activities in interaction with domestic proponent as well as opponent groups. This analysis shows that the transnational actors successfully laid the foundation for the commercial wind energy development throughout the 1990s but experienced marginalisation during the sector expansion due to the dominance of the central government and its protectionist industrial policy. As the domestic opponent groups caused high-level wind curtailment in the 2010s, the international advocacy group has increasingly conducted offensive norm promotion activities. This case of the Chinese wind energy development suggests that the international transfer of technology and policy measures in combination with the mobilisation of economic resources support the growth of the wind energy sector, which nonetheless suffers lacking influence of environmental norms and faces conflicts with the traditional players of the electricity sector. Based on these findings, this study concludes that the key socio-political condition for energy transition is the formation of a power configuration which facilitates the effectiveness of environmental norms and thus confronts the powerful opponents of wind energy.