• Structural Engineering and Mechanics
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• v.53 no.5
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• pp.957-979
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• 2015

The present paper investigates the influence of the orientation of the ground-motion reference axes, the seismic incident angle and the seismic intensity level on the inelastic response of asymmetric reinforced concrete buildings. A single storey asymmetric building is analyzed by nonlinear dynamic analyses under twenty bi-directional ground motions. The analyses are performed for many angles of incidence and four seismic intensity levels. Moreover three different pairs of the horizontal accelerograms corresponding to the input seismic motion are considered: a) the recorded accelerograms, b) the corresponding uncorrelated accelerograms, and c) the completely correlated accelerograms. The nonlinear response is evaluated by the overall structural damage index. The results of this study demonstrate that the inelastic seismic response depends on the orientation of the ground-motion reference axes, since the three individual pairs of accelerograms corresponding to the same ground motion (recorded, uncorrelated and completely correlated) can cause different structural damage level for the same incident angle. Furthermore, the use of the recorded accelerograms as seismic input does not always lead to the critical case of study. It is also shown that there is not a particular seismic incident angle or range of angles that leads to the maximum values of damage index regardless of the seismic intensity level or the ground-motion reference axes.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.461-466
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• 2012

Recently, building energy systems with solar collector and solar module have increased to improve energy problem, a heat island, a global warming and carbon dioxide emissions. In this study, value of solar radiation in areas was analyzed using TRNSYS simulation, and the optimum tilt and orientation angle for installing a photovoltaic module was examined. Average values of the weather data in the past twenty years in areas were used as input data. The results show that the tilt angle of a photovoltaic module for gaining the annual maximum solar radiation varies in different localities, and values of the annual solar radiation gained by using the variable photovoltaic module increased by 2.5 percent as compared with that gained by using the fixed photovoltaic module. When fixed photovoltaic module is installed, it should be examined the tilt and orientation angle for installing a photovoltaic module was examined.

• Journal of Korean Neurosurgical Society
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• v.58 no.4
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• pp.341-345
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• 2015

Objective : To measure the orientation of the facet joints of cervical spine (C-spine) segments in the sagittal plane, known as the pedicle-facet (P-F) angle, and to use these measurements to evaluate the relationship between the P-F angle and the amount of vertebral anterolisthesis in patients with degenerative cervical spondylolisthesis (DCS). Methods : A retrospective case-control study was performed including 30 age- and sex-matched patients with DCS and 30 control participants. Anterior-posterior and lateral view radiographs of the C-spine were obtained in a standing position. The P-F angle at all cervical levels and the amount of anterolisthesis at C4-5 were measured from lateral view plain radiographs. Results : The P-F angles at C4-5 were $141.14{\pm}7.14^{\circ}$ for the DCS group and $130.53{\pm}13.50^{\circ}$ (p=0.012) for the control group, and at C5-6 were $137.46{\pm}8.53^{\circ}$ for the DCS group and $128.53{\pm}16.01^{\circ}$ for the control group (p=0.001). The mean P-F angle at C4-5 did not correlate with the amount of anterolisthesis (p=0.483). The amount of anterior slippage did correlate with age (p<0.001). Conclusion : The P-F angle was intrinsically higher at C4-5, compared to C5-6, in both the DCS and control groups, which might explain the increased likelihood for anterolisthesis of C4. Higher P-F angles in the DCS group may be a predisposing factor to slippage. The P-F angle may interact with age to increase incidence of anterolisthesis with increasing age.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.5
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• pp.357-364
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• 1998

To investigate accuracies between intensity method and count method for measurement of the fiber orientation distribution, fiber orientation function is derived by drawing simulation figure for the fiber orientation as varying fiber aspect ratio, fiber area ratio, and fiber orientation state, respectively. The values of fiber orientation function measured by intensity method and count method are compared with the calculated ones from simulation figures. The results show that measurement accuracy of fiber orientation angle distribution obtained by count method is by 4% higher than that by intensity method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.10 s.181
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• pp.2496-2501
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• 2000

High speed ball end milling is attracting interest in the aerospace industry for the machining of complex 31) airfoil surfaces in nickel based superalloys, Experimental work is detailed on the effect of cutter orientation on tool life, cutting forces, chip formation, specific force and workpiece surface roughness, when high speed ball end milling nickel based supperalloy(lnconel 718). Dry cutting was performed using 8min diameter solid carbide cutters coated with either TiA1N or CrN for the workpiece mounted at an angle of 45˚ from the cutter axis. A horizontal downwards cutting orientation provided the best tool life with cut lengths~50% longer than for all other directions. Evaluation of cutting forces and associated spectrum analysis of results indicated that cutters employed in a horizontal downwards direction produced the least vibration.

• Journal of the Korean Magnetics Society
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• v.4 no.4
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• pp.313-318
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• 1994

We have investigated the effects of deposition angle on magnetic and magneto-optic properties in Co/Pt multilayer thin films. which were prepared bye-beam evaporation on tilted substrates. with varying tilt angle from $0^{\circ}$ to $60^{\circ}$. The structure of the specimens was examined by x-ray diffractometer and scanning electron microscope. and the magnetic and magneto-optical properties were measured by VSM, torque magnetometer, and Kerr loop tracer. X-ray diffractometry revealed that all of the specimens had multilayer structure and growth orientation of column followed the tangent rule but the crystallograpic orientation, <111>, was slightly deviated from the substrate normal even though the deposition angle was increased up to $60^{\circ}$. A decrement of the magnetization and Kerr angle with the deposition angle was related with that of the film density due to increasing porosity. The perpendicular mag¬netic anisotropy was also decreased with increasing the deposition angle.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.6
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• pp.566-576
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• 2003

Carbon-fiber reinforced plastics (CFRP) composite laminates often possess strong in-plane elastic anisotropy attributable to the fiber orientation and layup sequence. The layup orientation thus greatly influences its properties in a composite laminate. It could result in the part being rejected or discarded if the layup orientation of a ply is misaligned. A nondestructive technique would be very beneficial, which could be used to test the part after curing and to require less time than the optical test. In this paper, ultrasonic scanners were set out for different measurement modalities for acquiring ultrasonic signals as a function of in-plane azimuthal angle. The motorized scanner was built first for making transmission measurements using a pair of normal-incidence shear wave transducers. Another scanner was then built fer the acousto-ultrasonic configuration using contact transducers. A ply-by-ply vector decomposition model has been developed, simplified, and implemented for composite laminates fabricated from unidirectional plies. We have compared the test results with model data. It is found that strong agreement are shown between tests and the model developed in characterizing cured layups of the laminates.

• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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• pp.50-53
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• 2012

This paper describes experimental study on GM-type pulse tube refrigerator (PTR). In a PTR, the pulse tube is only filled with working gas and there exists secondary flow due to a large temperature difference between cold-end and warm-end. The stability of secondary flow is affected by orientation of cold-head and thus, the cooling performance is deteriorated by gas mixing due to secondary flow. In this study, a single stage GM-type pulse tube refrigerator is fabricated and tested. The cooing performance of the fabricated PTR is measured as varying cold-head orientation angle and the results are used as reference data. Then, we divided interior space of pulse tube into three segments, and fixed the various size of screen mesh at interface of each segment to suppress the performance degradation due to secondary flow. For various configuration of pulse tube, no-load test and heat load test are carried out with the fixed experimental condition of charging pressure, operating frequency and orifice valve turns. From experimental results, the fine screen mesh shows the effective suppression of performance degradation for the large orientation angle, but the use of screen mesh cause the loss of cooling capacity rather than the case of no insertion into pulse tube. It should be compromised whether the use of screen mesh in consideration of the installation limitation of a GM-type pulse tube refrigerator.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.39-49
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• 1999

This paper describes the development of a vision-aided position and orientation recognition system for automatically adjusting electronic tuners which control the waveform by rotating variable resisters. The position and orientation recognition system estimates the center and the angle of the tuner grooves so that the main controller may correct the difference from the ideal position and thereby manipulate the variable resisters automatically. In this paper a robust algorithm is suggested which estimates the center and the angle of the tuner grooves fast and precisly from the source image with lighting variance and video noise. In the algorithm morphological filtering, 8-chain coding, and invariant moments are sequentially used to figure out image segments concerned. The performance of the proposed system was evaluated using a set of real specimens. The results indicate the system works well enough to be used practically in real manufacturing lines. If the system adopts a high speed frame grabber which enables real time image processing, it can also be applied to positioning of robot manipulators as well as automated PCB adjusters.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1131-1139
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• 2001

Experimental results are presented, which describe the effect of blowing ratio on film cooling from two rows of holes with opposite orientation angles. The inclination angle is fixed at 35°, and the orientation angles are set to be 45°for the downstream row, and -45°for the upstream row. The studied blowing ratios are 0.5, 1.0 and 2.0. The boundary layer temperature distributions are measured using thermocouple at two downstream locations. Detailed adiabatic film cooling effectiveness and heat transfer coefficient distributions are measured with TLC(Thermochromic Liquid Crystal). The adiabatic film cooling effectiveness and heat transfer coefficient distributions are discussed in connection with the injectant behaviors inferred from the boundary layer temperature distributions. Film cooling performance, represented by heat flux is evaluated from the adiabatic film cooling effectiveness and heat transfer coefficient data. The results show that the investigated geometry provides improved film cooling performance at the high blowing ratios of 1.0 and 2.0.