• Journal of Korean Neurosurgical Society
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• v.47 no.2
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• pp.107-111
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• 2010

Objective : It has been demonstrated that cervical laminoplasty is an effective and safe method of treating multi-level cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. However, recent reports have suggested that axial neck pain is frequently encountered after cervical laminoplasty. The aim of the present study was to determine clinical significance of the C7 spinous process on axial neck pain after cervical laminoplasty. Methods : A total of 31 consecutive patients that underwent cervical laminoplasty between March 2002 and December 2008 were reviewed. The authors evaluated and compared axial neck pain and lordotic angle in patients that underwent C7 spinous process preserving surgery (group 1, n=16) and in patients in which the C7 spinous process was sacrificed (group 2, n=15). Results : Severe or moderate early axial pain occurred in 56.2% of patients in group 1 and in 86.6% in group 2. Severe or moderate late axial pain occurred in 12.5% in group 1 and in 73.3% in group 2. Eighty-Six percent of patients in group 2 and 43% in group 1 experienced aggravation of their axial neck pain during the early postoperative period. Aggravation of axial neck pain during early postoperative period was less common in group 1 but not statistically significant (p=0.073). Sixty-six percent of patients in group 2 and 12% in group 1 had aggravated axial neck pain at late postoperative period and aggravation of late axial neck pain was significantly less common in group 1 (p=0.002). Conclusion : The present study demonstrates that C7 spinous process preserving laminoplasty decreases the incidence of aggravated axial neck pain after cervical laminoplasty.

• Earthquakes and Structures
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• v.18 no.6
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• pp.677-689
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• 2020

A building structural system of moment resisting frame (MRF) with concrete filled steel tubular (CFST) columns and wide flange H beams, is one of the most conveniently constructed structural systems. However, there were few studies on evaluating seismic performance of full-scale CFST columns under high axial compression. In addition, some existing famous design codes propose various limits of width-to-thickness ratio (B/t) for steel tubes of the ductile CFST composite members. This study was intended to investigate the seismic behavior of CFST columns under high axial load compression. Four full-scale square CFST column specimens with a B/t of 42 were carried out that were subjected to horizontal cyclic-reversal loads combined with constantly light, medium and high axial loads and with a linearly varied axial load, respectively. Test results revealed that shear strength and deformation capacity of the columns significantly decreased when the axial compression exceeded 0.35 times the nominal compression strength of a CFST column, P₀. It was obvious that the higher the axial compression, the lower both the shear strength and deformation capacities were, and the earlier and faster the shear strength degradation occurred. It was found as well that higher axial compressions resulted in larger initial lateral stiffness and faster degradation of post-yield lateral stiffness. Meanwhile, the lower axial compressions led to better energy dissipation capacities with larger cumulative energy. Moreover, the study implied that under axial compressions greater than 0.35P₀, the CFST column specimens with B/t limits recommended by AISC 360 (2016), ACI 318 (2014), AIJ (2008) and EC4 (2004) codes do not provide ultimate interstory drift ratio of more than 3% radian, and only the limit in ACI 318 (2014) code satisfies this requirement when axial compression does not exceed 0.35P₀.

• Journal of Magnetics
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• v.16 no.1
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• pp.36-41
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• 2011

If gas is leaking out of gas pipelines, it could cause a huge explosion. Accordingly, it is important to ensure the integrity of gas pipelines. Traditionally, over the years, gas-operating companies have used the ILI system, which is based on axial magnetic flux leakage (MFL), to inspect the gas pipelines. Relatively, there is a low probability of detection (POD) for the axial defects with the axial MFL-based ILI. To prevent the buried pipeline from corrosion, it requires a protective coating. In addition to the potential damage to the coating by environmental factors and external forces, there could be defects on the damaged coating area. Thus, it is essential that nondestructive evaluation methods for detecting axial defects (axial cracks, axial groove) and damaged coating be developed. In this study, an electromagnetic acoustic transducer (EMAT) sensor was designed and fabricated for detecting axial defects and coating disbondment. In order to validate the performances of the developed EMAT sensor, experiments were performed with specimens from axial cracks, axial grooves, and coating disbondment. The experimental results showed that the developed EMAT sensor could detect not only the axial cracks (minimum 5% depth of wall thickness) and axial grooves (minimum 10% depth of wall thickness), but also the coating disbondment.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.563-572
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• 2001

With the results of calculation for natural frequencies the reponses of forced coupled vibration of propulsion shafting system were investigated by the modal analysis method. For the forced vibration response analysis, the axial exciting forces, the axial damper/detuner, propeller exciting forces and damping coefficients were extensively considered. As the conclusion of this study, some items are cleared as follows.-The torsional vibration amplitudes are not influenced by the radial excitation forces of the crank shaft. -The axial vibration amplitudes are influenced by the tangential exciting forces as well as the radial exciting forces of the crank shaft. The increase of the amplitudes is observed in the speed range at the neighbourhood of any torsional critical speed. 1The closer the torsional and axial critical speed. the larger coupling effect becomes. -The axial exciting force of propeller is relatively strong comparing with axial exciting forces of cylinder gas pressure and oscillating inertia of reciprocating mechanism. Therefore, the following conclusions are obtained. -Torsional vibration calculation with the classical one dimensional model is still valid. -The influence of torsional excitation at each crank upon the axial vibration is improtant. especially in the neighbourhood of a torsional critical speed. That means that the calculation of axial vibration with the classical one dimensional model is inaccurate in most of cases.

• Journal of Advanced Marine Engineering and Technology
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• v.5 no.1
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• pp.34-51
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• 1981

Lately, due to increasing engine output by high supercharging, heavy crankshaft and propeller mass, as well as long strokes attended with the reduced crankshaft axial stiffness, the critical crankshaft axial vibration has frequently appeared in maneuvering range of the engine. Some investigators have developed calculating methods of natural frequencies and resonant amplitudes for crankshaft axial vibrations. But their reliabilities are uncertain as the estimated crankshaft axial stiffness are incorrect. The calculating procedure of these natural frequencies is practically analogous to the classical calculation of torsional vibration frequencies, except for an important difference due to the relationship of the axial stiffness of a crank and the angle between the crank and other, especially the adjacent, cranks. In this paper, 6 calculation formulae of crankshaft axial stiffness already published and a theoretically- developed one by authors are checked by comparing their calculating results with those measured values of one model crankshafat and three full-scale actual crankshafts. Also, the calculating methods of the crankshaft axial free vibration are investigated and their computer programs are developed. Finally, those developed computer programs are applied to calculating one model crankshaft and two full-scale actual crankshafts of ship's propulsion engines and their calculated results are compared with those measured values.

• Advances in concrete construction
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• v.10 no.4
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• pp.289-299
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• 2020

A reliability analysis of the axial compressive load bearing capacity of postfire reinforced concrete (RC) columns strengthened with carbon fiber reinforced polymer (CFRP) sheets was presented. A 3D finite element (FE) model was built for heat transfer analysis using software ABAQUS. Based on the temperature distribution obtained from the FE analysis, the residual axial compressive load bearing capacity of RC columns was worked out using the section method. Formulas for calculating the residual axial compressive load bearing capacity of the columns after fire exposure and the axial compressive load bearing capacity of postfire columns retrofitted with CFRP sheets were developed. Then the Monte Carlo method was used to analyze the reliability of the axial compressive load bearing capacity of the RC columns retrofitted with CFRP sheets using a code developed in MATLAB. The effects of fire exposure time, load ratio, number of CFRP layers, concrete cover thickness, and longitudinal reinforcement ratio on the reliability of the axial compressive load bearing capacity of the columns after fire were investigated. The results show that within 60 minutes of fire exposure time, the reliability index of the RC columns after retrofitting with two layers of CFRPs can meet the requirements of Chinese code GB 50068 (GB 2001) for safety level II. This method is effective and accurate for the reliability analysis of the axial load bearing capacity of postfire reinforced concrete columns retrofitted with CFRP.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.541-547
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• 2000

Experiments were done for the comparison of performance and flow characteristics between a two stage axial flow fan and a counter-rotating axial flow fm. The fan performance curves were obtained by the Korean Standard Testing Methods for Turbo Fans and Blowers (KS B 6311). The fan flow characteristics were measured using a five-hole probe by the non-nulling method. Each stage of the two stage axial flow fan used for the present study has an eight bladed rotor and thirteen stator blades. The front and the rear rotor of the counter-rotating axial flow fan have eight blades each and are driven by coaxial counter rotating shafts through a gear box located between the rear rotor and the electric motor. Both of the two axial fan configurations use identical rotor blades and the same operating conditions for the one-to-one comparison of the two. Performance characteristics of the two configurations were obtained and compared by varying the blade setting angles and axial gaps between the blade rows. The passage flow fields between the hub and tip of the fans were measured and analyzed for the particular operating conditions of peak efficiency, minimum and maximum pressure coefficients.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.65-78
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• 1988

The development of good arch form, the orientation of the dentition with relation to the craniofacial skeleton and the establishment of correct relationship of axial inclination of upper and lower teeth are required in normal occlusion, but different teeth present different degrees of axial inclination. The purpose of this study was to investigate the axial inclination of upper and lower teeth by analyzing $45^{\circ}$ oblique and $90^{\circ}$ cephalometric roentgenograms of 35 Korean males and 34 females with normal occlusion. The obtained results were as follows: 1. Mean and standard deviation of mesiodistal axial inclination of upper and lower teeth related to palatal plane and occlusal plane were obtained. 2. Mesiodistal axial inclination of upper first premolar was nearly perpendicular to palatal plane, and the axis of lower first premolar was nearly perpendicular to occlusal plane. 3. There was no difference in the mesiodistal axial inclination of anteriorly positioned teeth between the three groups: third molar eruption into good alignment (Group 1), third molar impaction or partial eruption (Group 2), third molar agenesis (Group 3). 4. There were low correlationships only between the axial inclination of central incisor and the mesiodistal axial inclination of canine and first premolar, but no correlationships between central incisor and posterior teeth behind first premolar.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.281-284
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• 2006

ASCE-ACI Committee 426 and 445, on Shear and Torsion, well noted in their report that recent research work regarding shear and torsion had been devoted primarily to members. But it was not logical approach of PSC members applied by axial force based on the shear deformation in web element. And it was not included that the effect of axial is to shift the shear strain(or crack width) in the web element versus the applied shear curve up or down by the amount by which the biaxial tension-compression state varies. The shear strength also increases or decreases, so that the change in shear strain at service load due to the presence of axial load is to some extent changed. Generally, in corresponding beams the shear strain at service load is less in the beam subject to axial compression and greater in the beam subject to axial tension, than in the beam without axial load. In particular, however, no research were available on the shear deformation in shear of PSC members with web reinforcement, subject to axial force in addition to shear and bending. Therefore, this study was basically performed to develop the program for the calculation of the shear deformation based on the shear effect of axial force in prestressed concrete members.

• Journal of the Korean Society of Radiology
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• v.8 no.6
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• pp.317-323
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• 2014

This study aims to suggest and test methods using an orally inserted guiding device in order to improve a motion artifact by involuntary oral motor such as removing one's dentures and swallowing saliva clinically structured cervical spine scan and to make the optimal image by minimizing motion artifact. A cervical spine test was conducted with 30 patients who wore dentures among those who had a cervical spinal disease from January 1, 2014 through June 30, 2014. As for testing methods, after removing denture, T1-TSE-Sagittal, T2-TSE-Sagittal, T1-TSE-Axial and T2-TSE-Axial were obtained in a normal position and a supine position; the orally inserted guiding device was inserted in patients' mouth; and then T1-TSE-Axial and T2-TSE-Axial were retested. As a result, in SNR, T1-TSE-Axial before inserting an orally inserted guiding device was $22.33{\pm}8.59$; T1-TSE-Axial after inserting the orally inserted guiding device was $25.21{\pm}7.93$; T2-TSE-Axial before inserting the orally inserted guiding device was $14.49{\pm}5.74$; and T2-TSE-Axial after inserting the orally inserted guiding device was $16.61{\pm}6.72$. In CNR, T1-TSE-Axial was measured at $0.23{\pm}0.01$ while T2-TSE-Axial at $0.21{\pm}0.01$. As a result of the qualitative analysis, T1-TSE-Axial before inserting the orally inserted guiding device was $3.49{\pm}0.11$; T1-TSE-Axial after inserting the orally inserted guiding device was $3.95{\pm}0.14$; T2-TSE-Axial before inserting the orally inserted guiding device was $3.25{\pm}0.18$; and T2-TSE-Axial after inserting the orally inserted guiding device was $3.68{\pm}0.09$. As a result of using an orally inserted guiding device, the resolution and contrast of the images improved as the patients' involuntary artifact decreased because of removing dentures and swallowing saliva, and it was found that the interpretation of the images and identification of the diseases improved.