• Structural Engineering and Mechanics
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• v.61 no.1
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• pp.49-63
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• 2017

This paper presents an original hyperbolic (first present model) and parabolic (second present model) shear and normal deformation theory for the bending analysis to account for the effect of thickness stretching in functionally graded sandwich plates. Indeed, the number of unknown functions involved in these presents theories is only five, as opposed to six or even greater numbers in the case of other shear and normal deformation theories. The present theory accounts for both shear deformation and thickness stretching effects by a hyperbolic variation of ail displacements across the thickness and satisfies the stress-free boundary conditions on the upper and lower surfaces of the plate without requiring any shear correction factor. It is evident from the present analyses; the thickness stretching effect is more pronounced for thick plates and it needs to be taken into consideration in more physically realistic simulations. The numerical results are compared with 3D exact solution, quasi-3-dimensional solutions and with other higher-order shear deformation theories, and the superiority of the present theory can be noticed.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.5-12
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• 2003

This paper discusses about the thickness effects on the structural durability of a bileaflet mechanical heart valve (MHV). In the study on the design and the mechanical characteristics of a bileaflet mechanical heart valve, the fluid mechanics analysis on the blood flow passing through leaflets, the kinetodynamics analysis on the rigid body motion of the leaflet induced by the pulsatile blood flow, and the structural mechanics analysis for the deformed leaflet are required sequentially and simultaneously. Fluid forces computed in the fluid mechanics analysis on the blood flow are used in the kinetodynamics analysis for the leaflet motion. Thereafter, the structural mechanics analysis for the deformed leaflet follows to predict the structural strength variation of the leaflet as the leaflet thickness changes. Analysis results show that structural deformations and stresses increase as the fluid pressure increases and the leaflet thickness decreases. Analysis results also show that the leaflet becomes structurally weaker and weaker as the leaflet becomes thinner and thinner.

• Structural Engineering and Mechanics
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• v.11 no.4
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• pp.461-468
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• 2001

The aim of this work is to establish the coefficient that defines the critical buckling load for isotropic annular plates of variable thickness whose outer boundary is simply supported and subjected to uniform pressure. It is assumed that the plate thickness varies in a continuous way, according to an exponential law. The eigenvalues are determined using an optimized Rayleigh-Ritz method with polynomial coordinate functions which identically satisfy the boundary conditions at the outer edge. Good engineering agreement is shown to exist between the obtained results and buckling parameters presented in the technical literature.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.209-216
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• 2003

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.82-85
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• 1988

In the present study, we have investigated a novel photothermal imaging technique in $80^{\circ}$ deposited Ge Se film which do not utilize silver and deposited a-$Ge_{25}Se_{75}$ films was measured with the exposure time and annealing time. The results showed that the maximum changing rate of thickness was 3% in exposured film and 14% in postexposure annealing film.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.295-299
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• 1996

This analysis is to investigate the benefits and disadvantages of increasing the pressure tube wall thickness for CANDU reactor. Creep analysis of the pressure tube was performed for slightly enriched uranium (SEU) to establish the reduction in axial elogation and diametral creep provided by a thicker wall pressure tube.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.141-151
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• 2007

The current standards and specifications for the road pavement construction have been developed based on materials and construction methods. The pavements constructed in accordance with those specifications do not guarantee high performance of pavements since they do not consider long-term performance of pavements. Therefore, as part of the study to develop performance-based construction standards for pavements, the payment adjustment methods based on the pavement performance are currently being developed. This paper presents preliminary studies performed to develop the payment adjustment methods when there is deficiency in the concrete slab thickness that is one oi the most important factors for the pavement design and construction. First, the payment adjustment methods in USA were investigated. Then, the AASHTO failure equation, the relationship between slab thickness and stress, and the relationship between stress level and pavement life were employed to propose the payment adjustment concepts based on the pavement performance for the deficient slab thickness. The variation in the slab thickness according to measurement locations was investigated by taking cores. In addition, the measurement methods of slab thickness and the variation of measured thicknesses depending on performers were analyzed, and finally the methodology to develop the thickness deficiency ranges for the use in the payment adjustment methods was proposed.

• Computers and Concrete
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• v.15 no.2
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• pp.141-166
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• 2015

In the present study, a Finite Element Model has been developed and used to study the effect of diameter to wall thickness ratio (D/t) of steel tube filled with concrete under axial loading on its behavior and load carrying capacity. The model is verified by comparing its findings with available experimental results. Influence of thickness and area of steel tube on strength, ductility, confinement and failure mode shapes has been studied. Strength enhancement factors, load factor, confinement contribution, percentage of steel and ductility index are defined and introduced for the assessment. A parametric study by varying length and thickness of tube has been carried out. Diameter of tube kept constant and equals to 140 mm while thickness has been varied between 1 mm and 6 mm. Equations were developed to find out the ultimate load and confined concrete strength of concrete. Variation of lateral confining pressure along the length of concrete cylinder was obtained and found that it varies along the length. The increase in length of tubes has a minimal effect on strength of tube but it affects the failure mode shapes. The findings indicate that optimum use of materials can be achieved by deciding the thickness of steel tube. A better ductility index can be obtained with the use of higher thickness of tube.

• Annals of Clinical Neurophysiology
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• v.19 no.2
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• pp.131-135
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• 2017

Background: Neuromuscular ultrasound can be used to assess the diaphragm. Before it can be used clinically, the reference ranges of diaphragm thickness and contractility must be determined. Methods: We measured the thickness of the diaphragm and the diaphragmatic thickening fraction (DTF) in 80 healthy volunteers with ultrasound and collected their demographic information to determine if age, sex, and body mass index (BMI) influence these measures. Results: The thickness of the diaphragm at resting end expiration was $0.193{\pm}0.044cm$ on the right side and $0.187{\pm}0.039cm$ on the left. The DTF was $104.8{\pm}50.6%$ on the right side and $114.9{\pm}49.2%$ on the left. Sex, weight, height, and BMI significantly affected the thickness of the diaphragm, but had little effect on the DTF. Conclusions: Normal reference values for the diaphragm should be helpful when evaluating the diaphragm. The DTF appears more useful than resting diaphragm thickness because it is affected less by individual variation.

• Journal of the Korea Furniture Society
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• v.19 no.6
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• pp.447-451
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• 2008

This study was carried out to know the difference of vapor transmission on the thickness of Paulownia wood(Paulownia tomentosa). The behavior of moisture transmission of wood thickness direction is generally estimated by vapor permeability and vapor transmission resistance. In general, Paulownia wood is known to use of inside material for furniture making, because of the excellent ability of vapor adsorption and/or desorption. Quarter sawing Paulownia wood material is prepared and the thickness is 6.0mm, 7.0mm, 8.0mm, 9.0mm, 10.0mm, respectively. The measurement of vapor transmission were conducted by the "cup method" in accordance with JIS(Japanese Industrial Standard) Z-0208. The experiment was made in the condition of 49.8mmHg vapor pressure difference and $40^{circ}C$ at constant temperature. From the experiment results, it was considered that Paulownia wood is very stable on moisture variation and any other material conditions. In this experiment we found that the vapor permeability and vapor permeance was reduced with the increase of wood thickness to vapor direction and vapor transmission resistance and specific vapor transmission resistance was increased with the increase of wood thickness to vapor direction. Besides moisture contents of adsorption and desorption side were about 5 percent and 14 percent, respectively. Mean value was 9.5 percent and about 10 percent in dry oven method. Moisture gradient was reduced with the increase of wood thickness for a small moisture difference of adsorption and desorption side.