• Structural Engineering and Mechanics
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• v.46 no.6
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• pp.809-825
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• 2013

In the present study, in reinforced concrete structures, beam-column connections are one of the most critical regions in areas with seismic susceptibility. Proper anchorage of reinforcement is vital to enhance the performance of beam-column joints. Congestion of reinforcement and construction difficulties are reported frequently while using conventional reinforcement detailing in beam-column joints of reinforced concrete structures. An effort has been made to study and evaluate the performance of beam-column joints with joint detailing as per ACI-352 (mechanical anchorage), ACI-318 (conventional hooks bent) and IS-456(full anchorage conventional hooks bent) along with confinement as per IS-13920 and without confinement. Apart from finding solutions for these problems, significant improvements in seismic performance, ductility and strength were observed while using mechanical anchorage in combination with X-cross bars for less seismic prone areas and X-cross bar plus hair clip joint reinforcement for higher seismic prone areas. To evaluate the performances of these types of anchorages and joint details, the specimens were assembled into four groups, each group having three specimens have been tested under reversal loading and the results are presented in this paper.

• International Journal of Reliability and Applications
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• v.10 no.2
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• pp.89-99
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• 2009

Oriented Strand Board (OSB) is an important engineered wood product used in housing construction which has a lower environmental impact or "carbon footprint." In this paper, reliability and statistical tools are applied to gain insights on the strand thickness of OSB panels. An OSB panel consists of several hundred wood strands that are resinated and pressed. The variability of OSB strand thickness for six manufacturers in the Eastern United States is examined as a whole, as well as individually. Little research exists on OSB strand thickness across mills even though strand thickness variability has been documented in laboratory experiments to greatly influence the dimensional stability of OSB panels. Our aims are to quantify and characterize strand thickness, plus apply reliability techniques, such as Kaplan-Meier curves, to characterize the probability of strand thickness. We further explore graphically and statistically the thickness of the strands.

• KIEAE Journal
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• v.13 no.1
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• pp.47-55
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• 2013

This study aims to evaluate the correlation between vertical solar radiation and the level of heating load according to the location and type of housing in multi-family apartments. This study shows that heating load is related with factors such as wall loss, window loss, ventilation loss and solar radiation gain. The heating load increases in the order of the middle floors, the highest floors and the lowest floors. The lowest and the highest floors are the most vulnerable floors, and it should be as emphasized as the middle floors. The heating load saving proposal contains 52 Alt. that shows heating load savings from min. 4% to max. 49%. The goal is to reduce the heating load of the highest and the lowest floors to the level of the middle floors. The result showed that there are 3 Alt. for the lowest floors and 16 Alt. for the highest floors as the heating load saving proposal. This study suggests integrated application to compose saving elements of heating load. so it could be utilized as a data for the construction of passive houses.

• Journal of Biosystems Engineering
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• v.13 no.2
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• pp.28-37
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• 1988

This study was conducted to construct the soil bin system and associated microcomputer-based data acquisition system which is to be used for the effective evaluation of wheel performance. The soil bin system consists of four main parts; soil bin, carriage drive system, test carriage and soil processing carriage. The test carriage was constructed to measure the five performance parameters of testing wheels; pulling forte, motion resistance, sinkage and rotational speed of test wheel, and speed of test carriage. The test wheel is powered by a hydraulic system up to 8 ps. Soil processing carriage was designed to provide uniform test soil condition across the toil bin, and reproduction of soil conditions found satisfiable. The data acquisition system consists of APPLE II PLUS microcomputer, strain amplifier, I/O interface, A/D converter, digital counter and various transducers. It takes about 0.86 seconds to measure a set of performance parameters and store on the floppy disk simultaneously. Series of experiment showed that this system can be used effectively for evaluating the wheel performance associated with soil.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.92.2-92.2
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• 2011

In view of the planned NASA's and ESA's Solar Probe Plus and Solar Orbiter missions, respectively, to probe the inner heliosphere and the Sun's corona, it is timely to investigate outstanding problems associated with the solar wind. Among them is the temperature anisotropy problem. As the solar wind expands into the interplanetary space, the density and magnetic field decreases radially, thus leading to temperature anisotropy ($T_{\parallel}{\gg}T_{\perp}$). However, the measured temperature anisotropy can at times be characterized by $T_{\perp}$ > $T_{\parallel}$, while at other times the measured $T_{\parallel}/T_{\perp}$ is much milder than predicted by adiabatic theory. Physical reasons remain poorly understood. This notwithstanding, it is known from plasma physics that for $T_{\perp}$ > $T_{\parallel}$ electromagnetic ion-cyclotron (EMIC) and mirror instabilities are excited, while for $T_{\parallel}$ > $T_{\perp}$, fire-hose instability is excited. By constructing the threshold conditions for various instabilities, one may construct a closure relation that may be useful for modeling the solar wind. In the present paper we discuss theoretical construction of the anisotropy-beta relation by means of quasi-linear theories of these instabilities. The present work complements previous efforts on the basis of linear theory, hybrid simulations, and empirical fits of observations.

• Korean Journal of Computational Design and Engineering
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• v.16 no.2
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• pp.146-155
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• 2011

As the seriousness of environmental pollution being on a rise, a low carbon and environment-friendly design for energy efficiency has been issued. With respect to energy in the construction industry, an adoption of BIM which is possible for the various energy performance assessments in the early design phase has been actively working on. In the most cases of energy performance assessment, the data compatibility from the lack of standard software and format became a problem and the improvement for data compatibility system has been needed. This study is to develop the IFC based IDF converter as a middleware which connects between BIM software and energy analysis software. For the building energy performance assessment, Energy Plus and IFC are selected for the standard energy analysis software and its file format. Parameters are organized by steps and the integrated material library is built so it is trying to reduce the existing problem of energy software interface as much as possible. The development of IDF Converter will promote the spread of related fields with increasing the BIM standard and the utilization of energy performance assessment.

• Wind and Structures
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• v.14 no.1
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• pp.55-70
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• 2011

This study investigates the design criteria required for wind barriers to protect vehicles running on an expressway under a high side wind. At the first stage of this study, the lateral deviations of vehicles in crosswinds were computed from the commercial software, CarSim and TruckSim, and the critical wind speeds for a car accident were then evaluated from a predefined car accident index. The critical wind speeds for driving stability were found to be 35 m/s for a small passenger car, yet 30 m/s for a truck and a bus. From the wind tunnel tests, the minimum height of a wind barrier required to reduce the wind speed by 50% was found to be 12.5% of the road width. In the case of parallel bridges, the placement of two edge wind barriers plus one wind barrier at center was recommended for a separation distance larger than 20 m (four lanes) and 10 m (six lanes) respectively, otherwise two wind barriers were recommended.

• International journal of steel structures
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• v.18 no.4
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• pp.1325-1335
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• 2018

This study dealt with investigating the seismic performance of the smart and shape memory alloy (SMA) and magnets plus rubber-spring (MRS) dampers and their effects on the seismic resistance of multiple-span simply supported bridges. The rubber springs in the MRS dampers were pre-compressed. For this aim, a set of experimental works was performed together with developing nonlinear analytical models to investigate dynamic responses of the bridges subjected to earthquakes. Fragility analysis and probabilistic assessment were conducted to assess the seismic performance for the overall bridge system. Fragility curves were then generated for each model and were compared with those of as-built. Results showed dampers could increase the seismic capacity of bridges. Furthermore, from system fragility curves, use of damper models reduced the seismic vulnerability in comparison to the as-built bridge model. Although the SMA damper showed the best seismic performance, the MRS damper was the most appropriate one for the bridge in that the combination of magnetic friction and pre-compressed rubber springs was cheaper than the shape memory alloy, and had the similar capability of the damper.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.11
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• pp.81-87
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• 2018

Among various types of geothermal heat pump systems, Vertical Closed-Loop Geothermal Heat Pump (VGSHP) has received increasing attention due to a variety of advantages such as the potential to be installed in a relatively small space and improved energy efficiency. In this research, the performance of VGSHP system coupled with heat storage tank was evaluated, by analyzing operational behavior of heat storage tank, the variations of heat pump energy performance due to the connection with heat storage tank, part load ratios characteristics of heat pump and the corresponding energy cost, compared to chiller and boiler based conventional system. The results of this study showed that the VGSHP system coupled with heat storage tank showed an energy saving effect of about 18% for cooling and about 73% for heating, and annual heating/cooling energy cost reduction of 43,000,000 KRW ($ 39,000), compared to the conventional air conditioning system. In addition, after considering both energy cost and initial investment cost including equipment, installation and auxiliary device expenses, payback period of approximately 11.8 years was required.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.10
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• pp.37-44
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• 2018

In this study, the effects of considering hourly metabolic rate variations for predicted mean vote (PMV) control on the heating and cooling energy and greenhouse gas emission were investigated. The case adopting PMV control taking the hourly metabolic rate into account was comparatively analyzed against the conventional dry-bulb air temperature control, using a detailed simulation technique. Under the assumption that all the apartments in Korea adopt the PMV control incorporating real-time metabolic rate measurements, nationwide reductions of primary energy and greenhouse gas emission were analyzed. As a result, PMV control considering hourly metabolic rate variations is expected to reduce national primary energy by 6.2% compared to conventional dry-bulb air temperature control, corresponding to reduction of 10,342 GWh. In addition, it turned out that 6.6% of tCO2 emission can be reduced by adopting PMV control, corresponding to nationwide reduction of greenhouse gas emission by approximately 1,720,000 tCO2.