• Wind and Structures
• /
• v.22 no.1
• /
• pp.89-106
• /
• 2016

With an aim to assess the wind damage to urban trees in more realistic conditions, the nonlinear dynamics of structured trees subjected to strong winds with different levels is investigated in the present paper. For the logical treatment of dynamical behavior of trees, material nonlinearities of green wood associated with tree biomechanics and geometric nonlinearity of tree configuration are included. Applying simulated fluctuating wind velocity to the numerical model, the dynamical behavior of the structured tree is explored. A comparative study against the linear dynamics analysis usually involved in the previous researches is carried out. The failure wind velocity of urban trees is then defined, whereby the failure percentages of the tree components are exposed. Numerical investigations reveal that the nonlinear dynamics analysis of urban trees results in a more accurate solution of wind-induced response than the classical linear dynamics analysis, where the nonlinear effect of the tree behavior gives rise to be strengthened as increasing of the levels of wind velocity, i.e., the amplitude of 10-min mean wind velocity. The study of relationship between the failure percentage and the failure wind velocity provides a new perspective towards the vulnerability assessment of urban trees likely to fail due to wind actions, which is potential to link with the practical engineering.

• Wind and Structures
• /
• v.29 no.6
• /
• pp.471-488
• /
• 2019

Wind pressure is a critical argument for the wind-resistant design of structures. The attempt, however, to explore the wind pressure field on buildings still encounters challenges though a large body of researches utilizing wind tunnel tests and wind field simulations were carried out, due to the difficulty in logical treatments on the scale effect and the modeling error. The full-scale measurement has not yet received sufficient attention. By performing a field measurement, the present paper systematically addresses wind pressures on the rectangular attic of a double-tower building. The spatial and temporal correlations among wind speed and wind pressures at measured points are discussed. In order to better understand the wind pressure distribution on the attic facades and its relationship against the approaching flow, a full-scale CFD simulation on the similar rectangular attic is conducted as well. Comparative studies between wind pressure coefficients and those provided in wind-load codes are carried out. It is revealed that in the case of wind attack angle being zero, the wind pressure coefficient of the cross-wind facades exposes remarkable variations along both horizontal and vertical directions; while the wind pressure coefficient of the windward facade remains stable along horizontal direction but exposes remarkable variations along vertical direction. The pattern of wind pressure coefficients, however, is not properly described in the existing wind-load codes.

• The Korean Journal of Quaternary Research
• /
• v.22 no.2
• /
• pp.43-44
• /
• 2008

In this brief present are about some advanced results from investigation geomorphology in basin of river Tui and distribution of relief their peculiarities, types morphogenetic, convert to ekzogen process of relief ( fluvial system, permafrost process, wind process, slope process etc) and dynamic process of sedimentation.

• Wind and Structures
• /
• v.26 no.1
• /
• pp.45-56
• /
• 2018

Wind damage of urban trees arises to be a serious issue especially in the typhoon-prone areas. As a family of tree species widely-planted in Southeast China, the structural behaviors of Plane tree is investigated. In order to accommodate the complexities of tree morphology, a fractal theory based finite element modeling method is proposed. On-site measurement of Plane trees is performed for physical definition of structural parameters. It is revealed that modal frequencies of Plane trees distribute in a manner of grouped dense-frequencies; bending is the main mode of structural failure. In conjunction with the probability density evolution method, the fragility assessment of urban trees subjected to wind excitations is then proceeded. Numerical results indicate that small-size segments such as secondary branches feature a relatively higher failure risk in a low wind level, and a relatively lower failure risk in a high wind level owing to windward shrinks. Besides, the trunk of Plane tree is the segment most likely to be damaged than other segments in case of high winds. The failure position tends to occur at the connection between trunk and primary branches, where the logical protections and reinforcement measures can be implemented for mitigating the wind damage.

• Journal of Animal Environmental Science
• /
• v.15 no.1
• /
• pp.17-28
• /
• 2009

PEB system is more economical when compared with structures commonly used Hot rolled and welded light H-beam was introduced in the Standard Livestock Housing. This study suggested more economical technology for structural design by the reduction of live load, relief of deflection limit and reduction of importance factor. And, when applying wind Load as a result of examination with Low Rise Building Systems Manual considering open model, we can know that when the wind load is big, enclosed model is more stable than open model. In short, Suggesting more economical model and providing the method to reduce natural disaster, by the application of PEB system and the development of technology for structural design, are considered to strengthen the competitive power of farmhouse.

• Journal of Environmental Science International
• /
• v.15 no.6
• /
• pp.527-532
• /
• 2006

The purpose of this study is to clarify the characteristic of urban heat island intensity in urban area formed at a basin. Thermal environments for basin-type cities are influenced by significant topographic relief winds. In this study, we analyzed the diurnal variations of the heat island intensity according to meteorological condition and season using AWS(Automatic Weather observation System) data in Daegu Metropolitan area for 1 year(3/April, 2003 $\sim$ 2/April, 2004). In this study, we defined the urban heat island intensity as the air temperature difference between two points, the downtown and the suburban area. The suburban area is located at valley mouth around the western tip of Daegu. The results are summarized as follows; 1. The maximum heat island intensity was recorded at early morning under the meteorological conditions, calm and clear 2. The heat island intensity was strong in the order of winter, fall, spring and summer. 3. The heat island intensity came out minus values in the afternoon. This phenomenon is known as a com mon for basin-type cities. 4. The heat island intensity was twice or more in clear and calm than not so.

• The Korean Journal of Pain
• /
• v.13 no.1
• /
• pp.105-110
• /
• 2000

Central neuropathic pain may occur in 10~20% of the patients after spinal cord injury. The central pain syndrome include spontaneous continuing and intermittent pain as well as evoked pain. The pain is evoked by non-noxious stimulation of the region (allodynia) and repeated stimulation (wind-up phenomenon). Four patients were referred suffering from severe pain, allodynia and hyperaesthesia after spinal cord injury. They had received conventional treatment with non-steroidal anti-inflammatory drugs, steroid, anticonvulsant, antidepressant and rehabilitation which failed to provide pain relief. We administered combination of low doses of morphine and ketamine (10 mg) through the epidural catheter with other conventional therapy. Satisfactory pain relief was achieved in each patient. The reduction of pain was not associated with severe side effects. The most bothersome side effect of ketamine was dizziness in one patient, only caused by bolus injection (ketamine 10 mg with normal saline 10 ml). This suggests synergy from this combination that provides an alternative treatment for central pain.

• Herbal Formula Science
• /
• v.12 no.2
• /
• pp.31-46
• /
• 2004

This report describes 61 studies related to the use of Semen Armeniacae Amarum main blended prescriptions from Donguibogam. The following conclusions were reached through investigations on the prescriptions that use Semen Armeniacae Amarum as a key ingredient. Semen Armeniacae Amarum blended prescriptions are utilized for 16 therapeutic purposes, for example, in symptoms of cough, excrements, wind, and pediatrics. In particular, 52.46% of the prescriptions appear in the chapter of cough, and 9.84% of those appear in the chapter of excrements. Prescriptions that utilize Semen Armeniacae Amarum as the main ingredient are used in the treatment of cough, asthma, lung disease, and constipation, and they are also used for treating 15 different types of diseases. Semen Armeniacae Amarum is used in pathogenic factors such as wind, wind with cold, and wind with moisture, in pathologies related to lung and digestive systems, and in those related to weakness, extravasated blood, and alcoholic drink-food. The actual amount of Semen Armeniacae Amarum blended has ranged at a wide variety of amounts from 5 pun to 5 don. 47.62% of the prescriptions used 1 don. When Semen Armeniacae Amarum is combined with base prescriptions such as Samyotang, Banhaenghwan, ljintang, etc and Herba Ephedrae, Rhizoma Pinelliae, and Pericarpium Citri Reticulatae, it ceases cough and asthma. In addition, when Semen Armeniacae Amarum is combined with Fructus Ponciri Seu Aurantii and Fructus Cannabis, it brings a relief in constipation.

• Wind and Structures
• /
• v.2 no.3
• /
• pp.133-150
• /
• 1999

Significant costs to the public and private sectors due to recent extreme wind events have motivated the need for systematic post-hurricane damage data collection and analysis. Current post disaster data are collected by many different interested groups such as government agencies, voluntary disaster relief agencies, representatives of media companies, academicians and companies in the private sector. Each group has an interest in a particular type of data. However, members of each group collect data using different techniques. This disparity in data is not conducive to quantifying damage data and, therefore, inhibits the statistical and spatial description of damage and comparisons of damage among different extreme wind events. The data collection does not allow comparisons of data or results of analyses within a group and also prohibits comparison of damage data and information among different groups. Typically, analyses of data from a given event lead to different conclusion depending upon the definition of damage used by individual investigators and the type of data collected making it difficult for members of groups to compare the results of their analyses with a common language and basis. A formal method of data collection and analysis-within any single group-would allow comparisons to be made among different individuals, hazardous events and eventually among different groups, thus facilitating the management and reduction of damage due to future disaster. This research introduces a definition of damage to single family dwellings, and a common method of data collection and analysis suited for groups interested in regional characterization of damage. The current state-of-data is presented and a method for data collection is recommended based on these existing data collection methods. A fixed-scale damage index is proposed to consider the damage to a dwelling's feature. Finally, the damage index is applied to three dwellings damaged by Hurricane Iniki (1992). The damage index reflects the reduced functionality of a structure as a single family detached dwelling and provides a means to evaluate regional damage due to a single event or to compare damage due to events of different severity. Evaluation of the damage index and the data available support recommendation for future data collection efforts.

• Journal of the Korean earth science society
• /
• v.30 no.5
• /
• pp.622-629
• /
• 2009

This study intended to collect data for evaluating the meteorological value of Upo Wetland which is the largest wetland in the downstream of Nakdong River. The observations were conducted in summer at the Upo Wetland and its surrounding paddy field that is the converted areas from a wetland to a paddy field. The following results are obtained: 1) The temperature of Upo Wetland area was $1^{\circ}C$ lower than the surrounding area during the day while it was a little higher during the night.; 2) The maximum wind speed in the Upo Wetland area was 3.5 m/s which is stronger than 1.6 m/s of its surrounding area. The south wind was observed in the farmland for most of the day while north winds and south winds alternated between day and night in Upo Wetland.; 3) In heat budget analysis, Upo Wetland was wasted in the form of latent heat rather than sensible heat in daytime.