• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.251-254
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• 2000

In this study, we investigated vertical distribution and seasonal changes of phytophlankton community in the Hae-Dong Reservoir from March 1999 to Feburary 2000. This reservoir is relativly small (surface area, 2.7 $km^2$) and is the source of drinking water supply to the eastern part of Pusan City. Samples were collected at 2 sites (1, 3, and 6 m; site 1, in front of the dam; site 2, inlet). The dominant group was Bacillriophyceae at both sites (over 63%), and other groups exhibited seasonal changes (high cyanobacterial density in summer; green algal communities in winter). Chrysophyceae and Dinophyceae were maintained lower level during the study period. Along the water depth, all classess of phytoplankton did not show distintive vertical distribution at both sites except during the blue-green algal bloom in the middle of July and late September. The phytoplankton community dynamics in the Hoe-Dong Reservoir was strongly affected by the hydrological factors such as concentrated precipitation and short retention time.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.87-95
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• 2020

The worldwide shortage of water resources is a major environmental issue. Using pure water for drinking and domestic purposes is a bigger issue than other environmental issues. Industrialization and Urbanization have even polluted rainwater. In China, when it rains, rainwater is stored on the roof or other sources of storage for daily use resulting in pollution. Several studies have been conducted to treat rainwater. The objective of this study is to evaluate the efficiency of constructed wetlands by using ACF as a medium. So, this study aims to treat rainwater in Wuhan city through a Composite Vertical Flow Constructed Wetlands. First, rainwater was stored in the tank while it flows out of the roof, further it is processed in constructed wetlands. The constructed wetlands is consisted with plants Calamus and Chives, adding ACF (prepared from luffa) has achieved great results in this study. Results show that the pollutants have been removed to a considerable level, there were significant differences in removal rates under different HRT at 6h, 9h and 12h respectively. Therefore, Composite Vertical Flow Constructed Wetlands is recommended for total nitrogen and Ammonia nitrogen and total phosphorus.

• Journal of Environmental Science International
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• v.13 no.4
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• pp.389-401
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• 2004

Seasonal and vertical distribution of water quality were investigated from May 2001 to June 2002 in Kumoh reservoir located nearby Kumi City, Kyungpook. Kumoh reservoir that lost the role of agricultural irrigation is currently of rapid eutrophication. The vertical distribution of DO was observed clinograde with hypolimnetic anoxic zone. T-P concentrations at the surface ranged from 0.008 to 0.152 mgP/L and T-N concentrations ranged from 1.4 to 3.0 mgN/L. The vertical and seasonal variation of T-N was smaller than T-P. DOC concentrations, indicator of organic matter pollution, ranged from 2.8 to 5.4 mgC/L. Apportionment of Total-DOC (T-DOC) indicated that 14% of T-DOC was attributed to Labile-DOC(L-DOC) and the rest was due to Refractory-DOC(R-DOC). The values of TSI(Trophic State Index) ranged between 44 and 52 indicating that Kumoh reservoir is under mesotrophic condition. The results of this study indicate that Kumoh reservoir is likely to be under influence of eutrophication and thus water quality will be aggravated. Therefore, the Kumoh reservoir requires further treatment to improve water quality and a plan of the reusing water resource should be developed.

• Journal of the Korean housing association
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• v.18 no.5
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• pp.133-141
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• 2007

The purpose of this study is to secure an evacuation time and to ensure safety by using an Ubiquitous Sensor Network computing when a fire breaks out at a super high-rise apartment housing. A super high-rise apartment housing that is a type of building to solve the problem of separation of the urban function and the phenomenon of hollowing out downtown has been on the increase, high-rise apartment housings occupying 52.7% of whole housings in 2005. However, if a fire breaks out, there would be serious damage since it accommodates many people and facilities as existence of vertical gigantism in the city. The architectural law in force has no clause on it which is universally applicable to general building, it is difficult to be applicable to a densely super high-rise apartment housing and there would be in danger of a resident's evacuation in the fire. Therefore, as a previous study to introduce an USN-based fire-warning facility and evacuation equipment, this study shows the improvement way after analyzing factors that are barriers to evacuaee's behavior of a super high-rise apartment housing and also shows establishment of the grade of vertical evacuation rank by SimuleX, one of the best computer simulation program.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.639-648
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• 2023

In modern society, UAM (Urban Air Mobility) transportation system is being developed as an alternative to urban traffic congestion and environmental problems, and electric vertical take-off and landing (eVTOL) is a combination of vertical take-off and landing function and electric power. It is attracting attention as an innovative next-generation transportation method as an eco-friendly alternative that reduces noise and air pollution by providing efficient mobility within the city. Since eVTOL development requires designing and implementing airframes suitable for various mission purposes, the power system needs to be developed as a platform concept before airframe development. In this study, we empirically proposed a test bench concept equipped with a stable power supply and an efficient control system, essential in developing a power platform with a combined function in the form of a fuselage and module type specialized for various mission purposes. The proposed drivetrain platform test bench consists of a system verifying the stable take-off and landing software and a power platform adjusting the motor's thrust. It will serve as a verification system that can be developed.

• Geomechanics and Engineering
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• v.23 no.5
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• pp.455-466
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• 2020

This paper presents analysis of the interaction between tunnel and Qanat with a particular interest for the optimization of Qanat shape using the discrete element code, PFC2D, and the results will be compared with the FEM results of PLAXIS2D. For these concerns, using software PFC2D based on Discrete Element Method (DEM), a model with dimension of 100m ^⁎ 100 m was prepared. A circular tunnel with dimension of 9 m was situated 20 m below the ground surface. Also one Qanat was situated perpendicularly above the tunnel roof. Distance between Qanat center and ground surface was 8 m. Five different shapes for Qanat were selected i.e., square, semi-circular, vertical ellipse, circular and horizontal ellipse. Confining pressure of 5 MPa was applied to the model. The vertical displacement of balls situated in ground surface was picked up to measure the ground subsidence. Also two measuring circles were situated at the tunnel roof and at the Qanat roof to check the vertical displacements. The properties of the alluvial soil of Tehran city are: γ_dry=19 (KN/㎥), E= 750 (kg/㎠), ν=0.35, c=0.3(kg/㎠), φ=34°. In order to validate the DEM results, a comparison between the numerical results (obtained in this study) and analytical and field monitoring have been done. The PFC2D results are compared with the FEM results. The results shows that when Qanat has rectangular shape, the tensile stress concentration at the Qanat corners has maximum value while it has minimum value for vertical ellipse shape. The ground subsidence for Qanat rectangular shape has maximum value while it has minimum value for ellipse shape of Qanat. The vertical displacements at the tunnel roof for Qanat rectangular shape has maximum value while it has minimum value for ellipse shape of Qanat. Historical shape of Qante approved the finding of this research.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.82-88
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• 2013

There are the stirring test and drain test in the daily performance test to determine the thermal performance of a domestic solar hot water system. The drain test is a test that measures the discharge heating rate while drain the hot water from the top of the storage tank and supply the city water to the bottom of the tank. From the perspective of the user, this drain test is more effective than the stirring test. In this study, the thermal performance were compared through the drain test for a passive type and an active type domestic solar hot water systems consisting of the same storage tank and collectors. At this point, a passive type was used the horizontal storage tanks, and an active type was used vertical storage tank. In the drain test, when the hot water drained up to the reference hot water temperature, an active type which have vertical storage tank represents excellent daily performance than a passive type which have horizontal storage tank regardless of weather conditions. The reason for this is because the vertical storage tank is advantageous to thermal stratification in the tank. After the drain test, the residual heat for the horizontal storage tank was much more than the vertical storage tank, but in the next day the amount of discharged heat were less than the those of vertical storage tank neither. Thus, the solar water heating system which have horizontal storage tank should be adopted preheating control method rather than separate using control method when connected with auxiliary heat source device.

• Asian Journal of Atmospheric Environment
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• v.9 no.2
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• pp.114-127
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• 2015

In the Mexico City Metropolitan Area (MCMA), ozone ($O_3$) concentration is still higher than in other urban areas in developed countries. In order to reveal the current state of photochemical air pollution and to provide data for validation of chemical transport models, vertical profiles of meteorological parameters and ozone concentrations were measured by ozonesonde in two field campaigns: the first one, during the change of season from wet to dry-cold (November 2011) and the second during the dry-warm season (March 2012). Unlike previous similar field campaigns, ozonesonde was launched twice daily. The observation data were used to analyze the production and distribution of ozone in the convective boundary layer. The observation days covered a wide range of meteorological conditions, and various profiles were obtained. The evolution of the mixing layer (ML) height was analyzed, revealing that ML evolution was faster during daytime in March 2012 than in November 2011. On a day in November 2011, the early-morning strong wind and the resulting vertical mixing was observed to have brought the high-ozone-concentration air-mass to the ground and caused relatively high surface ozone concentration in the morning. The amount of produced ozone in the MCMA was estimated by taking the difference between the two profiles on each day. In addition to the well-known positive correlation between daily maximum temperature and ozone production, effect of the ML height and wind stagnation was identified for a day in March 2012 when the maximum ground-level ozone concentration was observed during the two field campaigns. The relatively low ventilation coefficient in the morning and the relatively high value in the afternoon on this day implied efficient accumulation of the $O_3$ precursors and rapid production of $O_3$ in the ML.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.140-145
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• 1999

In this study, noise analyses were performed toward ten school and one library-building adjacent to road. In particular, noise levels measured in the case-study city were compared to those from environmental noise standard as well as to encouraged noise level. In the analyses, the following conclusions are emphasized in order to make comfortable educational learning environment. 1) When windows were open, the measured noise level of 9 schools exceeded the encouraged noise level. In order to mitigate the exceeded level, it is necessary to plant trees or lawn and install soundproofing wall. 2) When windows were closed, the measured noise level of the most schools showed lower than that of encouraged level. For sound insulation, installing both double window and casement window are required. 3) Schoolhouse's vertical arrangement from the road in order to minimize the expected noise effect, and provision of green space by which visual hiding as well as psychological comfort are presumably achieved.

• International Journal of High-Rise Buildings
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• v.4 no.2
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• pp.135-142
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• 2015

As the skyscraper matures as a building type, its role in actively connecting to, and reinforcing, major threads of urban fabric becomes increasingly more important. The creation of public spaces inside of and adjacent to tall buildings allows for significant additions to the public realm, facilitating better connections between varied uses, providing needed access to critical transportation functions. In this more integrated version of the tall building type, the density afforded by a vertical structure is complemented by strategically devised porosity of plan and section. This paper examines three major tower projects which exemplify a progressive approach to permeable design: the recently completed Jingan Kerry Centre in Shanghai, the Lotte Supertower in Seoul, now half completed, and the One Vanderbilt tower being proposed next to Grand Central Terminal in New York City. These projects suggest possibilities for innovative approaches to private development strategies, public planning processes, and architectural design.