• International Journal of Aeronautical and Space Sciences
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• v.12 no.2
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• pp.93-114
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• 2011

The current status of Canadian research on rotor-based actively controlled technologies for helicopters is reviewed in this paper. First, worldwide research in this field is overviewed to put Canadian research into context. Then, the unique hybrid control concept of Carleton University is described, along with its key element, the "stiffness control" concept. Next, the smart hybrid active rotor control system (SHARCS) projected's history and organization is presented, which aims to demonstrate the hybrid control concept in a wind tunnel test campaign. To support the activities of SHARCS, unique computational tools, novel experimental facilities and new know-how had to be developed in Canada, among them the state-of-the-art Carleton Whirl Tower facility or the ability to design and manufacture aeroelastically scaled helicopter rotors for wind tunnel testing. In the second half of the paper, details are provided on the current status of development on the three subsystems of SHARCS, i.e. that of the actively controlled tip, the actively controlled flap and the unique stiffness-control device, the active pitch link.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.457-469
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• 1997

A nuclear spent fuel shipping cask is required by IAEA and domestic regulations to withstand a 9m free drop condition. In this paper, the structural analysis under the 9m side drop condition was performed to understand the dynamic impact behavior and to evaluate the safety of the cask for 7 PWR nuclear spent fuel assemblies. The analysis result was compared with the measured value of the 9m side drop test for the 1/3 scaled-down model and the accuracy of the 3D analysis was confirmed. Analysis in accordance with the diameter of impact limiters for the proto-type cask were performed. Through the analysis, the impact behaviors due to the side drop and the effects dependent on the diameter of impact limiters were grasped. Maximum stress intensities on each part of the cask were respectively calculated by using the stress evaluation program and the structural safety of the cask was finally evaluated in accordance with the regulations.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.243-247
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• 2005

This paper describes an on-going national R&D program for the development of a gas turbine/fuel cell hybrid power generation system and related R&D activities. The final goal of this program is to develop a 200kW-c1ass gas turbine/fuel cell hybrid power generation system and achieve high efficiency over $60\%$ (AC/LHV). In the first phase of the development, a sub-scaled 60kW-class hybrid system based on the 50kW-class microturbine and the 5kW SOFC will be developed for the purpose of concept proof of the hybrid system. Core components such as the microturbine and the SOFC system are being developed and parallel preparation for system integration is being carried out. Before the core components are assembled in the final system. operating characteristics of a hybrid system are investigated from a simulated system where a turbocharger (microturbine simulator) and a modified fuel cell burner test facility (fuel cell simulator) are employed. The 60kW demonstration unit will be built up and operated to provide the valuable information for the preparation of the final full scale 200kW hybrid system.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.376-381
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• 1998

The large scaled field test by prefabricated vertical drains was performed to evaluate the superiority of vertical discharge capacity for drain materials through compare and analyze the time-settlement behavior with drain spacing and the compression index and consolidation coefficient obtained by laboratory experiments and field monitoring system 1. The relation of measurement settlement( $S_{m}$) versus design settlement( $S_{t}$) and measurement consolidation ratio( $U_{m}$) versus design consolidation ratio( $U_{t}$) were shown $S_{m}$=(1.0~l.1) $S_{t}$, $U_{m}$=(1.13~l.17) $U_{t}$, at 1.0m drain spacing and $S_{m}$=(0.7~0.8) $S_{t}$, $U_{m}$=(0.92~0.99) $U_{t}$ at 1.5m drain spacing, respectively. 2. The relation of field compression index( $C_{cfield}$) and virgin compression index( $V_{cclab}$) was shown $C_{cfield}$=(1.0~1.2) $V_{cclab}$, But it was nearly same value when considered the error with determination method of virgin compression index and prediction method of total settlement. 3. field consolidation coefficient was larger than laboratory consolidation coefficient, and the consolidation coefficient ratio( $C_{h}$/ $C_{v}$) were $C_{h}$=(2.4 ~ 3.0) $C_{v}$. $C_{h}$=(3.5 ~ 4.3) $C_{v}$ at 1.0m and 1.5m drain spacing and increased with increasing of drain spacingngasing of drain spacingng spacingng

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.3
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• pp.168-175
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• 2015

This study consists of an experimental investigation of the reduction of the second-order roll motion of a semi-submersible platform in head sea conditions by adding hull damping. The second-order heave drift force and roll drift moment are known to be the main triggers that induce the list angle (Hong et al., 2010). Hong et al. (2013) used numerical calculations to show the possibility of reducing the list angle by changing the pontoon shape and adding a damping device on the hull. One of their findings was that the reduction in the list angle due to the increase in pontoon surface damping was significant. A series of model tests were carried out with a 1:50 scaled model of semi-submersible at the KRISO wave basin. The experiments indicated that adding damping on the hull surface effectively suppressed the list angle.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1207-1212
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• 2007

The critical speed of railway bogie related to the stability of the railway rolling-stock is important. Testing of the dynamic performance of bogie is conducted using a roller rig in a laboratory in place of field testing on track. This roller rig is composed of two rollers equivalent to track and used to test the dynamic characteristics of vehicle. But, the geometrical characteristics of the wheel/roller contact on the roller rig are different from those of the wheel/rail contact because the longitudinal radius of roller is not infinite compared with rail. This difference has influence on the wheelset behavior and the critical speed of bogie. Therefore in this paper, we have studied the behavior of wheelset and bogie on the roller rig for railway bogie testing with the purpose of developing the scaled roller rig. As an analysis results, it has been shown that the critical speed of bogie on the roller rig is slightly lower than that of bogie on track.

• Structural Engineering and Mechanics
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• v.25 no.1
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• pp.39-52
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• 2007

This paper describes an experimental study on structural health monitoring of a 1:3-scaled one-story concrete frame subjected to seismic damage and retrofit. The structure is tested on a shaking table by exerting successively enhanced earthquake excitations until severe damage, and then retrofitted using fiber-reinforced polymers (FRP). The modal properties of the tested structure at trifling, moderate, severe damage and strengthening stages are measured by subjecting it to a small-amplitude white-noise excitation after each earthquake attack. Making use of the measured global modal frequencies and a validated finite element model of the tested structure, a neural network method is developed to quantitatively identify the stiffness reduction due to damage and the stiffness enhancement due to strengthening. The identification results are compared with 'true' damage severities that are defined and determined based on visual inspection and local impact testing. It is shown that by the use of FRP retrofit, the stiffness of the severely damaged structure can be recovered to the level as in the trifling damage stage.

• Wind and Structures
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• v.24 no.2
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• pp.145-169
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• 2017

The auxiliary structures of a high-rise building, such as balconies, ribs, and grids, are usually much smaller than the whole building; therefore, it is difficult to simulate them on a scaled model during wind tunnel tests, and they are often ignored. However, they may have notable effects on the local or overall wind loads of the building. In the present study, a series of wind pressure wind tunnel tests and high-frequency force balance (HFFB) wind tunnel tests were conducted on rigid models of an actual super high-rise building with vertical ribs protruding from its facades. The effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and the most unfavorable values of the local wind pressure coefficients were investigated by analyzing the distribution of wind pressure coefficients on the facades and the variations of the wind pressure coefficients at the cross section at 2/3 of the building height versus wind direction angle. In addition, the effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and power spectra of the overall aerodynamic force coefficients were studied by analyzing the aerodynamic base moment coefficients. The results show that vertical ribs significantly decrease the most unfavorable suction coefficients in the corner recession regions and edge regions of facades and increase the mean and fluctuating along-wind overall aerodynamic forces.

• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.663-674
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• 2017

This paper presents an approach for evaluating performance of prestressed concrete (PC) bridge girders exposed to fire. A finite element based numerical model for tracing the response of fire exposed T girders is developed in ANSYS. The analysis is carried out in three stages, namely, fire temperature calculation, cross sectional temperature evaluation, and then strength, deformation and effective prestress analysis on girders exposed to elevated temperatures. The applicability of the computer program in tracing the response of PC bridge girders from the initial preloading stage to failure stage, due to combined effects of fire and structure loading, is demonstrated through a case study, and validated by test data of a scaled PC box girder under ISO834 fire condition. Results from the case study show that fire severity has a significant influence on the fire resistance of PC T girders and hydrocarbon fire is most dangerous for the girder. The prestress loss caused by elevated temperature is about 10% under hydrocarbon fire till the girder failure, which can lead to the increase in deflection of the PC girder. The rate of deflection failure criterion is suggested to determine the failure of PC T girder under fire.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.39-50
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• 2004

One of the challenge for successful daylighting design might be to capture sunlighting that varies in both intensity and position and to deliver the luminous flux into the inner space as deep as possible. Conventional glazing apertures allow daylight in the outer 3.5m of a perimeter spaces. More advanced daylighting technologies can extend this daylighting depth by reflecting sunlight further from the windows within a deep floor area. For this purpose, this study developed light shelves based on performance evaluation with a mock-up model that constructed recently and measured under real sky condition. All these daylighting devices have a customized geometry developed from the solar path at a given latitude and utilize unique reflecting finishing to maximize the amount of redirection and diffusion of the daylight. This paper tells that the best daylighting penetration typically can be expected from using light-colored sloped external shelves.