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Minimally invasive procedure through polydeoxynucleotide injection into torn area of supraspinatus tendon on US could be candidate for the safe and effective treatment on shoulder pain and limited range of motion in patients with rotator cuff tear.

Even though the measures to minimize the stack effect in high-rise buildings were taken that include a revolving door on the lobby floor, additional barriers to the passage of air in the lower part of the building, and air-tightness reinforcement for elevator doors, the stack effect is still present during cold season in Korea. However, it is difficult to fully apply the measures for stack effect under occupied condition in high-rise buildings. In this study, as an advanced method to lower the stack effect in high-rise buildings under occupied condition, mechanical ventilation in elevator shaft space, which cools the shaft space with outdoor air and reduces the temperature or pressure differences between indoor air in shaft and outdoor air, was proposed. In this paper, the application details and performance analyses of the installed shaft cooling system in a completed building in Korea were described. Also, as a measure to improve the performance of the applied system, concentrated cooling in the lower part of the elevator shaft where there is a main air flow passage was proposed. As a result, cooling effect of mechanical ventilation system in elevator shaft was improved and the extent of stack effect in winter was decreased effectively.

Drafts in high-rise buildings caused by the stack effect can cause noise and reduce the performances of ventilation, cooling and heating systems as well as the building’s energy efficiency. Revolving doors are generally used as a method to reduce drafts; however, the effect would only be limited to the main entrance on the lobby floor. Revolving doors have two main advantages; that their opening areas are seldom changed by people passing through the doors, and the doors do not have the pressure-related functional problems. Considering these advantages, this study examined a quantitative draft reduction method using revolving doors in high-rise buildings. This method would contribute to the design process to install revolving doors to buildings and consists of 10 steps with two key steps of selecting the installation locations of revolving doors and to calculate the air leakage area of revolving doors. Verification through simulations showed that, based on this process, the use of revolving doors could reduce the drafts in buildings by a quantified target value. Furthermore, the possibility of problems due to the stack effect in the other walls of buildings would decrease due to the pressure sharing of the additional walls fitted to revolving doors.

Efficient control of ventilation and cooling/heating systems in buildings is integral to making adjustments to indoor environments and to minimizing energy use. In high-rise buildings, however, the stack effect is generated through vertical shafts in the buildings, and the air flow due to the stack effect greatly affects the efficiency of air-conditioning systems used for ventilation, cooling, and heating. Therefore, attenuating the stack effect in high-rise buildings is a critical aspect of HVAC operations as well as a solution for direct problems related to the stack effect, such as high-velocity draft, high-level noise in the buildings, and so on.In general, as a method to attenuate the stack effect in high-rise buildings, revolving doors are installed at the lobby entrance. However, while this method may be effective on the floors where revolving doors are applied, the efficiency is very low when considering the entire building due to the existence of many air flow paths and the fact that revolving doors applied to only part of a building can control only a portion of the air flow. Numerical simulation analysis was performed in this study to quantitatively examine the stack effect attenuation characteristics of revolving doors on both a partial building level and for the entire building. In addition, the effects of building height and airtightness on the performance of the building envelope were considered.Keywords: stack effect; revolving door; stack effect attenuation; numerical simulation; high-rise buildings IntroductionSkyscrapers are currently being competitively constructed throughout Asia. As cities are becoming Manhattanized, the possibility of the stack effect in these new high-rise buildings inevitably increases. At the same time, the magnitude of problems created by the stack effect continues to grow. Problems generated by the stack effect in skyscrapers can mainly be divided into problems related to habitability and problems related to the performance of disaster prevention. The problems related to habitability, such as the occurrence of high-velocity drafts and highlevel noise in buildings, the incorrect operation and operational inability of doors, difficulty in controlling indoor cooling/heating environments, and so on, have been recognized as major problems resulting from the stack effect.The diffusion of poisonous gases from a fire is one of the concerns related to disaster prevention. If a fire