• Geomechanics and Engineering
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• 제24권6호
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• pp.589-597
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• 2021

The present study evaluates geocell reinforced slope behavior. A three dimensional analysis is carried out to simulate soil and geocell elastoplastic behavior using the finite difference software FLAC3D. In order to investigate the geocell reinforcement effect, the geocell aperture size, thickness, geocell placement condition and soil compaction had been considered as variable parameters. Moreover, a comparison is evaluated between geocell reinforcing system and conventional planar reinforcement. The obtained results showed that the pocket size, thickness and soil compaction have considerable influence on the geocell reinforcement slope performance. Moreover, it was found that the critical sliding surface was bounded by the first geocell reinforcement and the slope stability increases, by increasing the vertical space between geocell layers. In addition, the comparison between geocell and geogrid reinforcement indicates the efficiency of using cellular honeycomb geosynthetic reinforcement.

• 한국정밀공학회지
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• 제13권9호
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• pp.38-45
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• 1996

The optical triangulation method has been used as a non-contact measuring method of three dimensional object whape. But this measuring method has narrow measuring range, non-linearity on steep slope surface and shadow effect. In this study, we discussed a new optical measurement method to overcome these kinds of demerits. The advantage of this new method is that it is possible to measure precisely the object shape having the steep slope surface without shadow effect. As exper- imental results, maximum displacement error was 200 .mu. m over the whole measuring when the incident angle on the object surface was within 60 degree.

• Steel and Composite Structures
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• 제4권3호
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• pp.189-209
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• 2004

The commonly used seismic design procedures to evaluate the maximum effect of both horizontal components of earthquakes, namely, the Square Root of the Sum of the Squares (SRSS) and the 30-percent (30%) combination rules, are re-evaluated. The maximum seismic responses of four three-dimensional moment resisting steel frames, in terms of the total base shear and the axial loads at interior, lateral and corner columns, are estimated as realistically as possible by simultaneously applying both horizontal components. Then, the abovementioned combination rules and others are evaluated. The numerical study indicates that both, the SRSS rule and the 30% combination method, may underestimate the combined effect. It is observed that the underestimation is more for the SRSS than for the 30% rule. In addition, the underestimation is more for inelastic analysis than for elastic analysis. The underestimation cannot be correlated with the height of the frames or the predominant period of the earthquakes. A basic probabilistic study is performed in order to estimate the accuracy of the 30% rule in the evaluation of the combined effect. Based on the results obtained in this study, it is concluded that the design requirements for the combined effect of the horizontal components, as outlined in some code-specified seismic design procedures, need to be modified. New combination ways are suggested.

• Computers and Concrete
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• 제7권5호
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• pp.403-419
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• 2010

The bond mechanism for reinforcing bars in concrete is equivalent to the normal contact and friction between the inclined ribs and the surrounding concrete. Based on the contact density model for the computation of shear transfer across cracks, an open-slip coupled model was developed for simulating three-dimensional bond behavior for reinforcing bars in concrete. A parameter study was performed and verified by simulating pull-out experiments of extremely different boundary conditions: short bar embedment with a huge concrete cover, extremely long bar embedment with a huge concrete cover, embedded aluminum bar and short bar embedded length with an insufficient concrete cover. The bar strain effect and splitting of the concrete cover on a local bond can be explained by finite element (FE) analysis. The analysis shows that the strain effect results from a large local slip and the splitting effect of a large opening of the interface. Finally, the sensitivity of rebar geometry was also checked by FE analysis and implies that the open-slip coupled model can be extended to the case of plain bar.

• Physical Therapy Rehabilitation Science
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• 제6권3호
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• pp.113-119
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• 2017

Objective: The objective of this study was to investigate the effects of Schroth's three-dimensional exercises in combination with respiratory muscle exercise (SERME) on Cobb's angle and functional movement screen (FMS). Design: Randomized controlled trial. Methods: Fifteen subjects with scoliosis were randomly assigned to two groups. Eight subjects were assigned to the experimental group and seven subjects were assigned to the control group. The experimental group underwent SERME using SpiroTiger (Idiag, Switzerland), while the control group performed only the Schroth's three-dimensional exercises (SE). Both groups performed exercises for one hour per day, three times a week for eight weeks. Cobb's angle, pulmonary function (forced vital capacity, forced expiratory volume at one second, and peak expiratory flow) and FMS were measured before and after the experiment. Results: After intervention, the SERME group showed a significant difference in Cobb's angle, FMS scores, and pulmonary function as compared to before intervention (p<0.05). In the SE group, there was a statistically significant difference in Cobb's angle, pulmonary function, and FMS scores compared to before intervention (p<0.05). The SERME group showed a significant difference in Cobb's angle and peak expiratory flow in pulmonary function compared to the SE group (p<0.05). Conclusions: The results suggest that SERME could be a more effective intervention for improvement of the Cobb's angle and pulmonary function for scoliosis patients.

• 한국해양공학회지
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• 제24권4호
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• pp.78-85
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• 2010

This study investigates reducing characteristics for the spreading of dredged soil and the diffusion of contaminant by silt protector curtain through three dimensional numerical experiment. The numerical medel is modified by combining the sediment transport characteristics for cohesive sediment into the previously developed model. Several numerical experiments have been given in order to investigate the reducing effect of silt protector using two dimensional numerical channel model under various parameters such as upstream flow velocity, depth of silt curtain and the position of dumped materials. Through the evaluation of several simulation results, we knew that the careful design has to be given in the determination of depth and position of silt protector.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 가을 학술발표회 논문집
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• pp.133-138
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• 1992

The three dimensional analysis of Framed-Tube structures is neither easy nor efficient because of longer computational time, large memory requirement, tedious input preparation and bulky output. An efficient analysis model for framed-tube structure is proposed in this study. The proposed model can save the computational effort by using the assumption of the rigid floor diaphragm effect and matrix condensation technique. Moreover, it is develpoed by assembling two dimensional frames using the link degrees of freedom which are temporary used to satisfy the vertical displacement compatibility at the corners of a framed-tube. The accuracy and the efficiency of this analytical model is established by comparing with the results using the computer code SAPIV which is based on the three dimensional finite element model.

• 대한기계학회논문집B
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• 제20권8호
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• pp.2707-2720
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• 1996

The aerodynamic design of the two-stages of centrifugal compressors in an 1.2MW industrial gas turbine is completed with the application of numerical analyses. The final shape of an intake, the axial guide vanes and a return channel is determined using several interactions between design and two-dimensional turbulent flow analysis, focused on the minimum loss of internal flows. The one-dimensional turbulent flow analysis, focused on the minimum loss of internal flows. The one-dimensional design and prediction of aerodynamic performances for the compressors are performed by two different methods; one is a method with conventional loss models, and the other a method with the two-zone model. The combination methods of the Betzier curves generate three-dimensional geometric shapes of impeller blades which are to be checked with a careful change of aerodynamic blade loadings. The impeller design is finally completed by the applications of three-dimensional compressible turbulent flow solvers, and the effect of minor change of design of the second-stage channel diffuser is also studied. All the aerodynamic design results are soon to the verified by component performance tests of prototype centrifugal compressors.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.458-471
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• 2020

Effect of pre-treatment and compression ratio on specific gravity (SG) and dimensional stability improvement of three lesser-used wood species from natural forest area of North Kalimantan Province, Indonesia had been investigated. Hot soaking at 80℃ for 3 hours within 2 and 5% of boron solution was applied as pre-treatment, while compression ratio applied was 20 and 40% from the initial thickness. Densification was conducted using hot pressing machine at 30 kg/㎠ of pressure and 160℃ of temperature for 15 minutes. Specific gravity was measured gravimetrically, while dimensional stability was evaluated through thickness swelling and water absorption as the indicator. Results show that SG of densified wood was influenced by wood species and compression ratio, but not by pre-treatment applied; while dimensional stability was influenced by wood species, compression ratio, and pre-treatment. Specific gravity and water absorption of densified wood was improved significantly. Specific gravity increased 28.86-63.03%, while water absorption decreased 12.80-15.89%. Thickness swelling of 20% densified wood was lower than that of 40% densified wood.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 봄 학술발표회 논문집
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• pp.357-364
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• 1998