• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.409-415
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• 2021

Medical waste management is becoming increasingly important, specifically in light of the current COVID-19 pandemic, as hospitals, clinics, quarantine centers, and medical research institutes are generating tons of medical waste every day. Previously, a traditional incineration process was utilized for managing medical waste, but the lack of landfill sites, and accompanying environmental concerns endanger public health. Consequently, an innovative sterilization shredding system was developed to resolve this problem. In this research, we focused on the design and numerical analysis of a shredding system for hazardous and infectious medical waste, to establish its operational performance. The shredding machine's components were modeled in a CAD application, and finite element analysis (FEA) was conducted using ABAQUS software. Static, fatigue, and dynamic loading conditions were used to analyze the structural stability of the cutting blade. The blade geometry proved to be effective based on the cutting force applied to shred medical waste. The dynamic stability of the structure was verified using modal analysis. Furthermore, an S-N curve was generated using a high cycle fatigue study, to predict the expected life of the cutting blade. Resultantly, an appropriate shredder system was devised to link with a sterilization unit, which could be beneficial in reducing the volume of medical waste and disposal time, thereof, thus eliminating environmental issues, and potential health hazards.

• Journal of Animal Environmental Science
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• v.18 no.1
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• pp.25-34
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• 2012

Noxious gases with malodorous substance concentrations in each stages of pig buildings were determined at a typical 400sow-scale farm to improve piggery environment. Using IAQ-300 and pDR-1000AN, continuous records for the concentration of $NH_3$, CO, $CO_2$, $NO_2$, $SO_2$, $H_2S$, $O_2$, and along with temperature, humidity, dust concentrates from individual pig pens were collected to analyze every 6 hours' condition of indoor environment for 24 hours' period. In most pig houses, the air quality at noon was good, while at night (00:00~06:00), air composition became noxious in all buildings. The order of buildings' air quality for 24 hrs was pregnant > farrowing > nursery > growing > finishing. The cause of air quality differences was presumed to be the differences of stocking density, defecating amount and the length of exposure time of slurry in indoors. In conclusion, well-designed building structure, proper control of stocking density, quick removal of excreta from pig pens and continuous ventilation are prerequisites to improve pig housing environment.

• Journal of Internet Computing and Services
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• v.23 no.2
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• pp.29-35
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• 2022

UV rays have beneficial or harmful effects on the human body depending on the degree of exposure. An accurate UV information is required for proper exposure to UV rays per individual. The UV rays' information is provided by the Korea Meteorological Administration as one component of daily weather information in Korea. However, it does not provide an accurate UVI at the user's location based on the region's Ultraviolet index. Some operate measuring instrument to obtain an accurate UVI, but it would be costly and inconvenient. Studies which assumed the UVI through environmental factors such as solar radiation and amount of cloud have been introduced, but those studies also could not provide service to individual. Therefore, this paper proposes a deep learning model to calculate UVI using solar object information and sunlight characteristics to provide an accurate UVI at individual location. After selecting the factors, which were considered as highly correlated with UVI such as location and size and illuminance of sun and which were obtained through the analysis of sky images and solar characteristics data, a data set for DNN model was constructed. A DNN model that calculates the UVI was finally realized by entering the solar object information and sunlight characteristics extracted through Mask R-CNN. In consideration of the domestic UVI recommendation standards, it was possible to accurately calculate UVI within the range of MAE 0.26 compared to the standard equipment in the performance evaluation for days with UVI above and below 8.

• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.49-56
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• 2018

BACKGROUND: The mobile vortex wet scrubber was developed to remove the harmful chemicals from accidental releases. However, there was a disadvantage that it was limitedly used for volatile organic compounds (VOCs) such as toluene according to the physicochemical properties. This study compared the removal efficiencies of an improved mobile scrubber on toluene and ammonia by applying diverse adsorption and absorption methods. METHODS AND RESULTS: The removal efficiencies on harmful chemicals were examined using various adsorption and absorption methods of water vortex process (C), phosphoric acid-impregnated activated carbon adsorption (PCA), pH-controlled water (pH 2.5) vortex process absorption with sulfuric acid (SWA) after ammonia exposure, granular activated carbon adsorption (GCA), and activated carbon mat adsorption (CMA) after toluene exposure. As a result, the best removal efficiency was shown in the SWA for ammonia and GCA for toluene. Also, the SWA and GCA methods were compared with different concentration levels. In the case of ammonia exposure (5, 10 and 25%), there was no difference by concentration levels, and the concentration in the outlet gradually increased, with pH change from acid to base. In the case of toluene exposure (50, 75 and 100%), the outlet concentration was higher relative to the exposure concentration in the initial 10 min, but the outlet concentration was remained steady after 10 min. CONCLUSION: The newly improved mobile scrubber was also effective in removing VOCs through adsorption techniques (activated carbon, activated carbon fiber, carbon mat filter etc.), as well as removing acid-base harmful chemicals by neutralization reaction.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.149-158
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• 2006

Current removing process is labor intensive and time consuming, employing a conventional grinding type manual machine. This manual tasks trigger various dangers such as unexpected traffic accidents or explosions of propane gas used for finalizing removing process, leading to health damage and environment pollution by dusts and noxious gases. Accordingly, it is necessity for the development of new alternative equipment. In this paper, we have developed a prototype equipment for road stripe removing made up with a high-pressure water-jet system as a mobile type system. The following shows the results. First, an analysis of the current road stripe removal process showed that it can be divided into a) preparation, b) removal and c) ground finishing. It also showed that the b) removal process requires equipment which can cover the whole process. Second, the study compared between the productivity of the developed equipment and conventional methods, and it obtained 280% productivity improvement compared to the conventional equipment.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.780-785
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• 2016

Heavy oil used as ship propulsion has a serious issue regarding exhaust emission of global warming. Recently, among large-scale merchant ships are using LNG as green ships so called ech-ships. In this study, an vaporizer and pipes under cryogenic and high pressure load were considered to evaluate structural integrity according to codes. Structural analysis of the vaporizer and pipes was performed using the commercial code, ANSYS. Integrity evaluation of the vaporizer based on von Mises stress was performed in accordance with allowable stress specified in ASME Boiler & Pressure Vesssel Section VIII Division 2. To assess structural integrity of the pipes, stress components were combined and compared with ASME B31.3. The calculated stresses for all load cases are lower than allowable stresses, therefore the structural integrity of equipments are verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.996-1003
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• 2019

The undergrounding of diverse ground facilities has led to a decrease in issues, such as foul smell of water supply systems and wastewater, a fall of telephone poles, electromagnetic waves and breaking of wires caused by a railway work. On the other hand, there are new issues, including a fall accident, explosion affected by flammable gas, a choking accident by harmful gas and a lack of oxygen concentration, a fire coming from high-tension wire heating and flooding in the manhole. Besides, these issues damage the civil society and are an anxiety to public safety. Therefore, this paper is focused on a smart manhole device for stable communication environments inside and outside the manhole and wireless communication with various devices for managing facilities in the manhole, and aims to make a contribution to public safety by suggesting a direction of future underground facility management.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.37-47
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• 2004

Sulfates such as alunite and schwertmannite formed under oxidation condition play a important role in geochemical processes taken place at waste dumps and a creek from Dalseong mine, Daegu. Water chemistry shows pH decreases from upstream toward downstream creek, mainly due to formation of schwertmannite that is the most abundant phase along the creek. The removal of Al from the creek is preferentially attributed to formation of Al-bearing minerals and Al-sulphates. Among them, alunite is the most important Al-sink phase that occurs at higher pH than $pK_1$, Al hydrolysis constant. With high saturation index, alunite formed at the creek has a spherical form, commonly associated with schwertmannite. Secondary minerals formed on the surface of altered or weathered surfaces of heavy metals from the wasted dump that underwent severe oxidation, where alunite has characteristic habits which are spheric, radiating, and botrytis-like aggregates. Natroalunite occurs in association with alunite, or as mixtures of both of them. Because the pH decreases with distance due to formation of schwertmannite, although total contents of dissolved ions slowly lessen at least in the AMD, it is expected that the minerals precipitated at the creek can be exposed to subsequent dissolution, which may induce possible environmental problems.

• Membrane Journal
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• v.21 no.3
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• pp.277-289
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• 2011

Since 1980s, wastewater treatment facilities in Korea have been rapidly expanded by 90 percent as the government invested them continuously. Considering social and environmental factors such as the needs of alternative water resources for water shortages, energy saving and new energy production sources for decrease of greenhouse gases, and the demand for the improvement of the water quality in rivers and lakes, advanced technologies in wastewater treatment are essential in the 21st century. In this aspect, new conceptual technology is systematically combined with the advanced treatment technology such as the control and treatment technology of hazardous and toxic material, customized reusing skill, and energy saving/recovery technology. The new R&D project for advanced technology of wastewater treatment and reuse will focus on these advanced technologies which will improve the water quality and foster the competitiveness in world environmental markets, building a solid foundation particularly in the market of developing countries. The project will be divided up into high quality reusing of wastewater, energy self-sufficiency, and integrated management system. It will be carried out for five years, 2011~2015, as Phase I.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.13-23
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• 2008

In coastal region, eutrophication, Do deficit and red tide are frequently occurred by influx of fresh water. When the fresh water containing pollutants is discharged into the sea, the surrounding water is contaminated by dispersion of freshwater flowing into coastal waters. The prediction and analysis about the dispersion process of the discharged fresh water should be conducted. A modeling system using GUI was developed to simulate hydrodynamic flow and fresh water dispersion in coastal waters and to analyze the results efficiently. The modeling module of the system includes a tide model using a finite element method and a fresh water dispersion model using a particle-tracking method. This system was applied to predict the tidal currents and fresh water dispersion in Mokpo coastal zone. To verify accuracy of the hydrodynamic model, the simulation results were compared with observed sea level and time variations of tidal currents showing a good agreement. The fresh water dispersion was verified with observed salinity distribution. The dispersion model also was verified with analytic solutions with advection-diffusion problems in 1-dimensional and 2-dimensional simple domain. The system is operated on GUI environment, to ease the model handling such as inputting data and displaying results. Therefore, anyone can use the system conveniently and observe easily and accurately the simulation results by using graphic functions included in the system. This system can be used widely to decrease the environmental disaster induced by inflow of fresh water into coastal waters.