Determining of the shape in the process of design for natural draught cooling tower is very important, because the shape of hyperbolic shell is respond sensitively to dynamic behavior of the whole cooling tower against wind load. In engineering practice, the geometric parameters have been determining based on the natural frequency. This study analyses influence of the tower shell geometric parameters on the structural behavior. For three representative models were selected, they were analyzed based on evaluation of damage by means of nonlinear FE-method. As a result, a hyperbolic rotational shell with the small radius overall was the lowest damage index induced by sufficient capacity of the stress redistribution and thus a wind-insensitive structure.

It is very important to calculate natural frequency of the observatory tower correctly because it is keenly affected by wind response vibration due to its large slenderness ratio, weight and small damping ratio. Additionally, suggestion equation of natural frequency being used in the design phase has considerable difference between actual measured value thereby making it inappropriate to be used in the serviceability design of the observatory tower. Therefore, this paper conducted an ambient vibration measuring on 10 observatory towers through mobile-phone application thereby calculating the natural frequency and comparing the result with the domestic and foreign standards and that of the eigen-value analysis. This paper suggested approximate equation of the natural frequency of the observatory tower; T=0.0266H. The square of the corelation coefficient is 0.940, which is high.

The initial production scale of wind tower is very few. But recently, the production scale of wind tower structure has increased gradually because it maximizes the efficiency in green energy. Many researchers are studying the wind tower, but there is no study about the difference of allowable buckling stress of the wind tower with and without opening. Guideline of codes and standards are very limited when designing a wind tower with an opening. It is also rarely that a study considers the design of the wind tower to be a tubular shell with or without an opening. ABAQUS, a general purpose finite element program, which provides safety evaluation and economical standards for the design and behavior of the wind tower considering the effect of opening was used in the study. Finally, results from this study can serve as reference for structural engineers, manufacturers and further studies of wind turbine when designing a tubular shell wind tower with an opening.

This study has implemented an experiment in which hydrogen sulfide was removed by establishing a two-stage packed tower effector filled with nutritious medium and also filling a tower that was immobilized in ceramic media after isolating and identifying the sulfur oxidizing bacteria from a sewage treatment plant. As a result, strains isolated from the sewage treatment plant were found to be similar, including Bacillus fusiformis, Bacillus anthracis sp., Paenibacillus sp., Serratia marcescens sp., Bacillus thuringiensis. The effector that immobilized isolated strains in the ceramic media achieved an approximately 90% removal rate of hydrogen sulfide, while the sterilized ceramic media not immobilized with isolated strains showed a removal rate of about 65%. In addition, the removal rate of hydrogen sulfide in the primary media packing effector immobilized with sulfur oxidizing bacteria was about 92%, while the secondary effector filled with medium had a hydrogen sulfide removal rate near 100%. In addition, 90% efficiency of removal was shown in conditions of EBCT 60s in the experiment that investigated removal rate of hydrogen sulfide according to residence-time, while the efficiency was rapidly reduced up to 45% in conditions of EBCT 30s. On the other hand, when operating for an extended period time while increasing the concentration of injected hydrogen sulfide, the amount of sulfate was increased from 2 mg/L to 12.7 mg/L, and pH was rapidly reduced to 2.7.

This study has implemented an experiment in which hydrogen sulfide was removed by establishing a two-stage packed tower effector filled with nutritious medium and also filling a tower that was immobilized in ceramic media after isolating and identifying the sulfur oxidizing bacteria from a sewage treatment plant. As a result, strains isolated from the sewage treatment plant were found to be similar, including Bacillus fusiformis, Bacillus anthracis sp., Paenibacillus sp., Serratia marcescens sp., Bacillus thuringiensis. The effector that immobilized isolated strains in the ceramic media achieved an approximately 90% removal rate of hydrogen sulfide, while the sterilized ceramic media not immobilized with isolated strains showed a removal rate of about 65%. In addition, the removal rate of hydrogen sulfide in the primary media packing effector immobilized with sulfur oxidizing bacteria was about 92%, while the secondary effector filled with medium had a hydrogen sulfide removal rate near 100%. In addition, 90% efficiency of removal was shown in conditions of EBCT 60s in the experiment that investigated removal rate of hydrogen sulfide according to residence-time, while the efficiency was rapidly reduced up to 45% in conditions of EBCT 30s. On the other hand, when operating for an extended period time while increasing the concentration of injected hydrogen sulfide, the amount of sulfate was increased from 2 mg/L to 12.7 mg/L, and pH was rapidly reduced to 2.7.

“탑”은 예이츠의 존재합일의 우수성을 밝히는 비밀이 담겨 있는 시이다. 이 시는 예이츠의 이원론은 플라톤과 플로티누스의 일원론이 가진 한계성을 극복하는 강점을 가지고 있다는 것을 암시적으로 드러내고 있다. 또한 이 시는 차별화된 죽음의 극복과정이 담겨 있다. 창조적인 상상력은 인간의 지성에 영향을 주고, 지성은 인간의 감정과 연결되어 평온의 상태를 만든다. 이 평온의 상태가 죽음을 극복하는 결정적 역 할을 수행한다. 결국에 지성과 감정이 연결되어 죽음을 실제적으로 극복하는 것이 이 시가 가진 독창성이다.

The study conducted statistical analysis of survey on the 239 workers participating in national Tower Crane installation/dismantlement in order to identify work environment and health hazard exposure of Tower Crane workers. Consequently for work related safety status of Tower Crane workers, the number of installation/dismantlement work was the highest at 15-20 times per month, and safety equipments were not arranged at work and they felt highly anxious when boarding on the Tower Crane. Furthermore, it is found that they feel anxious working in the influence of the weather, noise, vibration, wind, the sun ray, and structure characteristic. They have very low satisfaction in the insecureness of workplace and the work environment, and recognizes that their work affect highly on the health. 81.6% of workers have experienced accident at work, the cause of accidents were mainly due to poor work environment, and the health abnormality they have experienced were mostly fatigue and concentration reduction. For job stress, job demand and conflict in relationship were the highest sections. Total 66.5% of workers complained of musculoskeletal disorder related subjective symptom, and back pain patients were the highest of all groups.

Cooling towers have been widely applied to control the indoor temperature in the residential area and the living space. At operating the cooling towers, motor, fan and dropping water produce noise and vibration, which diffuse through the air or the solid object, polluting the environment. The standards can be used at estimating noise and vibration emission by showing remarkable economic or social benefits. The purpose of this study is to show the characteristics, measurement methods for the evaluation of noise and vibration in cooling tower.

Recently, wind power has received attention as one of remarkable renewable energy resources, and worldwide researches about wind power are actively being proceeded. Wind turbine tower has a major role for safety in the wind turbine systems. It is necessary for design tower structure to consider various environmental conditions. Earthquake, as one of the such environmental loads, is ground motion that applied to bottom of the tower structure and has a possibility of critical effect to the wind tower structure. There are various ways for seismic analysis, but design specifications that are in use do not suggest detailed method for seismic analysis. In this study, seismic responses are analyzed through different ways and the adequacy of seismic design methods is examined.

This study analyzes buckling in the lower segment of a tubular steel shell that exhibits the characteristics of a 3MW wind tower with opening and reinforcement. Analytical method using parametric equations based on Eurocode 3 - Design of Steel Structures and numerical method of finite element are used to analyze the critical meridional buckling stress. ABAQUS, a finite element program, is used for the numerical method analysis. Four different cases of tubular steel tower is modeled: without door opening and without reinforcement; with door opening and without reinforcement; without door opening and with reinforcement; and with door opening and with reinforcement. Using the ABAQUS, a linear buckling analysis is done for all cases to recognize five of its buckling mode shapes and its corresponding eigenvalues. Mode shapes from the previous analysis are considered in performing the non-linear analysis using Static Riks. Buckling capacity and its trends in the localized area near the opening is investigated, tabulated and shown in illustrative charts. Moreover, comparison is made between the parametric and finite element analyses.

FRP members which have light weight, high specific strength and stiffness, and good corrosion resistance are used widely in the electrical transmission system. Recently, FRP instead of steel, wood, and concrete tower is installed and in use. In this paper, we investigated the feasibility of replacement of traditional materials (steel, wood, and concrete) in electrical transmission towers by the fiber reinforced polymer plastic (FRP) members through the literature review. It was found that the FRP electrical transmission towers were applied in many countries due to its various advantages.

풍력발전 타워는 높은 세장비를 갖는 형상으로 인해 바람에 의해 발생하는 횡하중에 취약한 구조를 가지고 있기 때문에 바람은 풍력발전 타워를 설계하는데 있어서 중요한 설계요소 중 하나라고 할 수 있다. 본 논문에서는 타워 운송 편의성 향상을 위해 설계된 8각 및 6각 단면형상을 가지는 조립식 강관 타워 및 일반 원형 강관 타워의 일정 높이 이상에서부터 4개의 작은 기둥으로 분리되는 형상을 가지는 멀티기둥 강관 타워에 대한 2차원 단면모형 풍동실험과 3차원 모형 풍동실험을 수행하여 각 형상별 풍력계수를 산정하여 그 특성을 비교하였다. 또한 풍동실험 축소모형에 대한 CFD 해석을 수행하여 산정된 풍력계수값의 신뢰성을 확인하였으며, 마지막으로 실제스케일 풍력타워에 대한 CFD 해석을 수행하여 각 형상별 특성을 분석하였다.

시각예술가인 저자는 자신의 드로잉과 설치작업 세계를 이해하기 위한 통찰을 제시하고자 한다. 저자는 미적-예술적 선과 대립되는 과학적-기술적 선의 현상과 효과를 고찰하고자 하면서, 발생할 수 있는 어떠한 유추에 대해 설명하고자 한다. 제도가로서 저자가 참고하는 자료들이 가지고 있는 과학적인 문제에 접근한다면 어떤 일이 생길까? 그것은 추측일까 혹은 인식일까? 선을 보다 구체적으로 다루려는 의도에서 저자는 예술적 그리고 과학적 관점에서 기하학의 근원적인 문제를 해결하고자 시도하였다. 저자는 일종의 번역작업으로 유클리드의 원리와 구성적 기술에 근거한 증명의 계도 형식의 도형을 만들고, 이 도형을 드로잉에 반영하고 있다. 저자는 드로잉 혹은 설치작업이 다양한 요소와 층위를 전개시키면서 본질적으로는 자체적으로 구성됨을 보여주고자 한다.

Wind turbine tower has a very important role in wind turbine system as one of the renewable energy that has been attracting attention worldwide recently. Due to the growth of wind power market, advance and development of offshore wind system and getting huger capacity is inevitable. As a result, the vibration is generated at wind turbine tower by receiving constantly dynamic loads such as wind load and wave load. Among these dynamic loads, the mechanical load caused by the rotation of the blade is able to make relatively periodic load to the wind turbine tower. So natural frequency of the wind turbine tower should be designed to avoid the rotation frequency of the rotor according to the design criteria to avoid resonance. Currently research of the wind turbine tower, the precise research does not be carried out because of simplifying the structure of the other upper and lower. In this study, the effect of blade modeling differences are to be analyzed in natural frequency of wind turbine tower.

As an offshore wind power turbine is bigger, a new-type supporting structure is required reduce any probability of risk such as its buckling failure. In this study, we analyzed free oscillation of ICH RC wind power tower based on the design sections in the previous study. Also, we checked the safety by resonance between designed ICH RC wind power towers and various commercial wind power turbines. The eigenvalue analysis results showed that the designed ICH RC wind power towers were free from the resonance by turbines.

In the case of the current ICH RC wind power tower, the design method is getting quite complicated especially if it gets higher. So we, based on the previous basic cross section designs of ICH RC wind power tower, have mapped out the tower structures considering the correlation between their heights and diameters in this research. The cross section dimensions along the tower height were designed according to recommendations of ‘Design Criteria for Concrete design (2012).’ The cross sectional diameter of the wind tower decreases as its location is higher, and this decreasing diameter accorded with the decreasing bending moment. All designed cross sections and tower modules were evaluated of their bending moment capacities and compared with the design moment. The analysis results and comparisons showed that all designed modules satisfied their required capacities.

Internally confined hollow reinforced concrete (ICH RC) wind power towers were designed for various turbines sizes. Their cross sections were designed to have equal diameters to those of general steel wind power towers corresponding 3.6MW and 5.0MW turbines. And also, the sections with the average diameter of 3.6MW and 5.0MW turbines were designed. For the determined diameters, several cross sections were designed for various hollow ratios. The designed sections were set to have almost equal longitudinal reinforcement ratios. The performance analyses for the designed cross sections were carried out and the analysis results showed that the ICH RC wind power tower had enough strength for the required design loads.