• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.493-498
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• 2008

Particles or deposit formed by corrosion of the pipe material bring about bad influences on the heating systems with inconvenience, energy loss and so on. In order to obtain the non-corrosive environments, the circulation hot water should properly be treated in several ways to satisfy one or more conditions of the followings: suitable pH-level, low hardness, low oxygen content, low conductivity, low level of chlorides and sulphur compounds and low level of solid particles. This experimental study was carried out to develope the new guidelines on the optimal water quality and directions for water quality management in heating systems. As results, it was recommended that the heating water be maintained pH-level not less than 8, hardness contents as $CaCO_3$ no more than 50 mg/L, turbidity no more than 10 NTU and T-Fe contents 1 mg/L below.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.5
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• pp.269-277
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• 2017

This study consists of an analysis of pre-existing ceiling construction systems as well as the development of a replacement unitary, lightweight steel ceiling system and related legal standards. Based on the material conditions and progression of the study, appropriate components were chosen and details were modified by mock-up test. A final study model was evaluated for performance and adaptability based on four parameters (indoor environment, constructability, budget economy, and aesthetics) and compared to the pre-existing ceiling system. As a result of the initial study, a lightweight steel design was created consisting of a reinforced structure with modular bars and entry holes for components. This system was hung directly on the suspension structure. The new design increased lighting and acoustic performance adapted to an indoor environment. Moreover, the speed of construction was increased by approximately 30%, the cost was decreased by approximately 20%, and ceiling aesthetics were improved.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2008.10a
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• pp.43-51
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• 2008

Currently an increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method (NATM). For rational management of tunnels from planning to construction and maintenance stages, prediction, control and monitoring of displacements of and around the tunnel have to be performed with high accuracy. Computational method tools, such as finite element method, have been and are indispensable tool for tunnel engineers for many years. It is, however, a commonly acknowledged fact that determination of input parameters, especially material properties exhibiting nonlinear stress-strain relationship, is not an easy task even for an experienced engineer. Use and application of the acquired tunnel information is important for prediction accuracy and improvement of tunnel behavior on construction. Artificial Neural Network (ANN) model is a form of artificial intelligence that attempts to mimic behavior of human brain and nervous system. The main objective of this paper is to perform the deformation analysis in NATM tunnel by means of numerical simulation and artificial neural network (ANN) with field database. Developed ANN model can achieve a high level of prediction accuracy.

• Korean Institute of Interior Design Journal
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• v.14 no.4 s.51
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• pp.106-113
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• 2005

The advancements of the society aggravate ecological problems, and it is at a point where our living environment is under a serious threat. To resolve such problems, environmental friendly design concepts are evolving through various naming conventions such as conservation of global environment, environmental symbiosis, friendly environmental, nature-friendly, environmental friendly type, green building and eco-construction. Accordingly, in this research, for the purposes of healthy living environmental construction, nature as the subject of its design and highly praised as a new design arena, floral art design theory and its functions, as well as its examples are explored. With the Information available, I was able to confirm that, in interior decorating, floral art design is used as a tool for expressing environmental friendly space, and gradually its necessity and the scope of its application have been broadened. Therefore, utilization of floral art design is to fabricate environmental friendly interior space; and it is expected as a substitute for accomplishing green amenity, and its study should continue for the years to come.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.143-144
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• 2019

Recently, environmental pollution related to global warming is on the rise. Meanwhile, renewable energy is a representative example of many efforts to develop eco-friendly energy to solve the depletion of natural resources and the depletion of petroleum resources in conjunction with global warming. Among them, photovoltaic power generation is increasing the subsidies for the government to increase the production of photovoltaic electricity of the general public, showing a high growth rate. However, polysilicon, which is a raw material of the photovoltaic panel, generates waste called polysilicon sludge in the manufacturing process. In order to produce 1 ton of polysilicon, about 2 tons of waste polysilicon sludge is generated. In 2012, polysilicon sludge was generated at 78,000 tons, with an average of about 220 tons per day. The sludge generated due to insufficient treatment of polysilicon sludge is currently solidified and is processed by landfilling. Therefore, in this study, polysilicone sludge is used as the concept of admixture, and the physical properties of the matrix according to the polysilicon sludge replacement ratio based on light burned magnesia is determined.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.21-22
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• 2019

In order to prevent global warming according to fossil fuel use, countries around the world are making efforts through the Kyoto Protocol and the Paris Climate Change Convention. In addition, in order to prepare for high oil prices, researches such as the development of various renewable energy are being conducted. At present, the domestic production rate of energy sources in Korea is low at 18.1%, and power plants using forest biomass are being constructed to meet the domestic situation where 63% of the land is a forest. In 2015, the global production of wood pellets, a raw material for wood-based biomass power generation, was 28 million tons, up 7.7% from 2014, and has increased tenfold over the last decade. This is a result of increased demand for biomass. Korea is also increasing every year. However, biomass fly ash, an industrial by-product generated by biomass energy generation, is now being disposed of entirely, and there is little research to utilize it. Therefore, this paper will use biomass fly ash, an industrial by-product, which is currently being discarded due to a lack of separate treatment methods, as an admixture concept to contribute to solving environmental problems, developing new admixtures, improving quality, and seeking recycling plans.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.277-282
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• 2006

In order to predict the indoor air pollutant, the VOCs emission rate is used through small chamber in the design process. However, the small chamber method has limitations as the convective mass transfer coefficient, the most important factor when predicting VOCs contamination of indoor air, is different between the small chamber result and the measured data in the actual building. Furthermore, the existing studies which analyzed mass transfer coefficient in the small chamber were directed on the small chambers developed at the time and FLEC(Field and Laboratory Emission Cell), thus, are different from the current small chamber which has been changed with improvements. The purpose of this study is to determine the emission rate of pollutant in double-layered building materials through the CFD(Computational of Fluid Dynamics) and Numerical analysis based on the mass transfer coefficient on singled-layered building material by using the current small chamber widely used in Korea. Futhermore, this study used the new convective mass transfer coefficient($h_m'$) which indicates the existing convective mass transfer coefficient($h_m$) including VOC partition coefficient(k). Also, formaldehyde was selected as target pollutant.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.43-49
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• 2004

With building structures becoming higher and having longer spans, new structural steel with better strength, thicker plate, and performance may be required rather than conventional structural steel. TMC steel is widely used in building structures largely due to its excellent seismic performance, superior weldability, and design strength that is not affected by plate thickness. To make use of TMC steel in pipe structures with large diameter and heavy wall, however, the this study, the degradation of material properties in submerged are welded SM520TMC steel pipes and tubes was evaluated using variable fabrication process and material change. Degradation test results showed that the yield and ultimate strength increased and elongation decreased regardless of the mode of fabrication, i.e., through roll bending or press forming, or steel used, i.e., domestic SM520TMC steel or SM520TMC steel from Japan.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1278-1289
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• 2008

Currently in increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method (NATM). Successful design, construction and maintenance of NATM tunnel in urban area demands prediction, control and monitoring of surface settlement, gradient and ground displacement with high accuracy. Use of measured displacement for parameter determination has been researched over the years, and one geotechnical engineering principle has been formed as back analysis. In this paper, back analysis of a ground deformational behavior involving nonlinear behavior is discussed. It is of primary importance to make reliable prediction of deformational behavior for shallow tunnels in soft ground. However, predictions made often prove to be incorrect due to complexity of constitutive law and other relevant factors. Back analysis therefore becomes more important, for it may be used to interpret measured displacement to derive nonlinear material characteristics. The paper shows some example in which a deformational mechanism is studied in the light of inhomogeneous distrubution of Young's module, from which a logic is derived to identify two different types of nonlinear constitutive relationships.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.100-106
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• 2014

High strength concrete has a structural advantage as well as superior usability and durability, so that its application in building is being steadily augmented. However, in the high temperature like in a fire, the high strength concrete has extreme danger named explosive spalling. It is known that the major cause of explosive spalling is water vapour pressure inside concrete. General solution for preventing concrete from spalling include applying fire protection coats to concrete in order to control the rising temperature of members in case of fire. The purpose of this study is to investigate the high temperature properties of fireproof mortar using organic fiber and various types of fine aggregate for fire protection covering material. The results showed that addition of perlite and polypropylene fiber to mortar modifies its pore structure and reduces its density. This causes the internal temperature to rise. As a results, it is found that a new fireproof mortar can be used in the fire protection covering material in high strength concrete.