• Asian Journal of Atmospheric Environment
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• v.11 no.4
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• pp.254-269
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• 2017

The work describes an assessment of the major air pollutants, $NO_2$, $SO_2$, CO, $O_3$, $NH_3$, coarse and fine particulate matter ($PM_{10}$, $PM_{2.5}$) in ambient air in and around a 3 million tonne Petroleum Refinery and the possible impacts on a pristine area marked by the presence of the world-famous Kajiranga National Park, a world heritage site and habitat for the most number of one-horned rhinos in the world. The Refinery is at an aerial distance of 20-25 km from the wildlife habitat. The assessment is based on regular monitoring at four stations around the Refinery and one station near the National Park. Heavy rains during June to August influence the pollutant concentrations while at other times of the year, large traffic volume adds to the pollutant concentrations that peak during November to March, the dry months of the year. Correlation analysis by scatter technique is utilised to obtain the enhancement ratios to predict the variations in the concentrations of the pollutants and their spatial distribution. Computation of air quality index (AQI) indicates that the coarse and the fine particulates in the ambient air could be a major hazard to wildlife in the area.

• Smart Structures and Systems
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• v.4 no.5
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• pp.655-666
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• 2008

In the past 20 years, seismic isolation has see a variety of applications in design of structures to mitigate seismic hazard. In particular, isolation has been seen as a means of achieving enhanced seismic performance objectives, such as those for hospitals, critical emergency response facilities, mass electronic data storage centers, and similar buildings whose functionality following a major seismic event is either critical to the public welfare or the financial solvency of an organization. While achieving these enhanced performance objectives is a natural (and oftentimes requisite) application of seismic isolation, little attention has been given to the extension of current design practice to isolated buildings which may have more conventional performance objectives. The development of a rational design methodology for isolated buildings requires thorough investigation of the behavior of isolated structures subjected to seismic input of various recurrence intervals, and which are designed to remain elastic only under frequent events. This paper summarizes these investigations, and proposed a consistent probabilistic framework within which any combination of performance objectives may be met. Analytical simulations are presented, the results are summarized. The intent of this work is to allow a building owner to make informed decisions regarding tradeoffs between superstructure performance (drifts, accelerations) and isolation system performance. Within this framework, it is possible to realize the benefits of designing isolated buildings for which the design criteria allows consideration of multiple performance goals.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.9
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• pp.57-63
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• 2012

The basic purpose of grounding is for human safety and normal operation of system related to electrical shock hazard by faults of electrical equipments. A grounding electrode is defined as a conducting element that connects electrical systems and/or equipment to the earth. The lowest possible resistance connection to the earth is sought from the grounding electrode. The grounding electrode is the foundation of the electrical safety system. The resistance to ground of vertical electrodes buried in the two deference soil structures has been analyzed for a length of electrodes and soil parameters. The equation of ground resistance of vertical electrodes are Tagg's equation for uniform soil models, and modified equation of Dwight equation for two-layer soil model. In this paper, compared with results of two equations are calculated values of vertical electrode in uniform and two-layer soil models.

• Journal of Biomedical Engineering Research
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• v.33 no.3
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• pp.105-113
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• 2012

Biopsy is a type of histopathological examinations, in which a physician samples cells or tissues from a patient's suspicious lesion. Such a lesion frequently resides deep inside human body, and then a percutaneous biopsy is therefore performed using a thick needle with the assistance of medical imaging such as computed tomography(CT) and magnetic resonance imaging(MRI). Recently modern robotic technology is being introduced to percutaneous biopsy in order to reduce any possible human error and hazard on physicians caused by medical imaging. After medical imaging locates the exact location of lesion, an optimization algorithm plans the path for a biopsy needle. Subsequently, a robot system moves the biopsy needle to the lesion in accurate and safe way with the control of a practitioner or automatically. In this article, we try to look into the state-of-art of percutaneous biopsy using such robotic technology. We classified percutaneous biopsy robots by mechanical characteristics and by imaging technology. Then, advantage and disadvantage of each class type are described as well as the basic description, and a few representative designs for each type are introduced. Current research issues of robotized percutaneous biopsy are subjectively selected for the readers' convenience. We emphasize the basic technology of actuator and sensors compatible with imaging technology to conclude this review.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.395-398
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• 2009

Currently, a new generation of ducted fan UAVs (Unmanned Aerial Vehicles) is under development for a wide range of inspection, investigation and combat missions as well as for a variety of civil roles like traffic monitoring, meteorological studies, hazard mitigation etc. The current study presents extensive results obtained experimentally in order to investigate the tip clearance effects on performance characteristics of a ducted fan for small UAV systems. Three ducted fans having different tip clearance gap and with same rotor size were examined under three different yawed conditions of calibrated slanted hot-wire probe. Three dimensional velocity flow fields were measured from hub to tip at outlet of the ducted fan. The analysis of data were done by PLEAT (Phase locked Ensemble Averaging Technique) and three non-linear differential equations were solved simultaneously by using Newton -Rhapson numerical method. Flow field characteristics such as tip vortex and secondary flow were confirmed through axial, radial and tangential velocity contour plots. At the same time, the effects of tip clearance on axial thrust and input power were also investigated by using wind tunnel measurement system. For enhancing the performance of ducted fan, tip clearance level should be as small as possible.

• Wind and Structures
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• v.27 no.2
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• pp.137-147
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• 2018

Heavy damages to properties with attendant losses were frequently caused by tornadoes in recent years. This natural hazard is one of the most destructive wind events that must be fully studied and well understood in order to keep the safety of structures and infrastructure facilities. On June 23, 2016, a severe tornado, which is an Enhanced Fujita (EF) 4 storm, occurred in the rim of a coastal city named as Yancheng in China. Numerous low-rise buildings as well as facilities (e.g., transmission towers) were destroyed or damaged. In this paper, damages to structures and infrastructure facilities by the severe tornado are reviewed. The collapses of residential buildings, industrial structures and other infrastructure facilities are described. With an overview of the damages, various possible mechanisms of the collapse are then discussed and utilized to reveal the initiation of the damage to various facilities. It is hoped that this paper can provide a concise but comprehensive reference for the researchers and engineers to help understand the tornado effects on structures and expose the vulnerabilities that need to be improved in current wind-resistant design practices.

• Journal of Korean Society of Rural Planning
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• v.19 no.4
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• pp.47-54
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• 2013

Climate change is the most direct threatening factors in sustaining agricultural productivity. It is necessary to reduce the damages from the natural hazards such as flood, drought, typhoons, and snowstorms caused by climate change. Through the vulnerability assessment to adapt the climate change, it is possible to analyze the priority, feasibility, effect of the reduction policy. For the vulnerability assessment, broad amount of weather data for each meterological station are required. Making the database management system for the meteorologic data could troubleshoot of the difficulties lie in handling and processing the weather data. In this study, we generated the meteorologic data retrieval system (MetSystem) for climate change vulnerability assessment. The user interface of MetSystem was implemented in the web-browser so as to access to a database server at any time and place, and it provides different query executions according to the criteria of meteorologic stations, temporal range, meteorologic items, statistics, and range of values, as well as the function of exporting to Excel format (*.xls). The developed system is expected that it will make it easier to try different analyses of vulnerability to natural hazards by the simple access to meteorologic database and the extensive search functions.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.83-89
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• 2013

Microbiological treatment, chlorination, and ozonation are usually used for water treatment. However, there is weakness that these methods can't decompose and eliminate recalcitrant organic pollutants perfectly. It is possible to eliminate recalcitrant organic pollutants when photocatalysis of $TiO_2$ is used. In this study, the removal efficiencies of organic pollutants by using photocatalyst of $TiO_2$ in the slightly polluted golf club water hazard and a river were investigated. The amount of $TiO_2$ was divided into three categories of 1 g/L, 2 g/L and 4 g/L in order to investigate the adequate amount of $TiO_2$ and the removal efficiency. UV light was used as a light source for the reaction of photocatalyst. As a conclusion in this study, the efficiency of turbidity removal was increased in proportion to the amount of $TiO_2$ until 4 hours. After then the turbidity was gradually decreased. Finally, the optimum concentration of $TiO_2$ was 4 g/L. The efficiency of COD removal was increased in proportion to the amount of $TiO_2$ regardless of time.

• Journal of Korean society of Dental Hygiene
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• v.14 no.4
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• pp.527-537
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• 2014

Objectives : The purpose of this study was to investigate the influence of the awareness towards dental radiation exposure and concern in the adults. Methods : A self-reported questionnaires was filled out by 470 adults over 19 years old in Seoul from May 16 to July 10, 2013. Results : Fear for dental radiography showed that those who positively thought of radiography had 2.86 folds necessity of radiography than those who did not. Positive responders worried about the hazards of dental radiation 4.64 folds than the negative responders. More worried responders had felt the radiation hazards 1.83 folds than those who worried less. The worried responders also had higher awareness of dental radiation hazards. Conclusions : Frequent use of dental radiography is able to be prevented by protective devices. So it is important to prevent the possible hazards of the dental radiography by personal protective education.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.50-55
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• 2001

Different polluted water samples were collected from a wastewater treatment plant, agricultural drainage canals, the River Nile, and irrigation canals. The samples were examined for the enumeration of Pseudomonas aeruginosa in the Sohag area, Egypt over a period of one year. A total of 240 isolates were collected and tested for their resistance to 12 common antibiotics and 6 heavy metals. The isolates were found to be less resistant to norfloxacin(1.7%), ofloxacin(4.6%), amikacin(9.6%), tobramycin (10.4), carbenicillin (15.4), and gentamycin (41.3%), yet more sensitive to rifampicin (75%), kanamycin (89.6%), ampicillin (90.8%), chloramphenicol (91.7%), streptomycin (92.9%), and tetracyclin(96.3%). In contrast, 7.1%, 12.9%, 25.4%, and 53.7% of the isolates were resistant to lead, cadmium, mercury, and zinc, respectively. None of the isolates had developed a resistance to silver or molybdenum. The high frequency of metal-antibiotic double resistance existed between lead and amikacin (56.5%), cadmium and ofloxacin (72.7%), zinc and norfloxacin (100%), and mercury and carbenicillin (94.6%). The high occurrence of antibiotic-resistant bacteria in natural water could be related to the widespread use of antibiotics, with possible public health hazard.