• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3602-3608
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• 2013

Saccharomyces cerevisiae, which is a common species of yeast, is by far the most extensively studied model of a eukaryote because although it is one of the simplest eukaryotes, its basic cellular processes resemble those of higher organisms. In addition, yeast is a commercially valuable organism for ethanol production. Since the yeast data can be extrapolated to the important aspects of higher organisms, many researchers have studied yeast metabolism under various conditions. In this report, we analyzed and compared metabolites of Saccharomyces cerevisiae under salt and pH stresses of various strengths by using two-dimensional NMR spectroscopy. A total of 31 metabolites were identified for most of the samples. The levels of many identified metabolites showed gradual or drastic increases or decreases depending on the severity of the stresses involved. The statistical analysis produced a holistic outline: pH stresses were clustered together, but salt stresses were spread out depending on the severity. This work could provide a link between the metabolite profiles and mRNA or protein profiles under representative and well studied stress conditions.

• Structural Engineering and Mechanics
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• v.57 no.4
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• pp.733-762
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• 2016

Based on a reduced displacement field, a layer-wise (LW) formulation is developed for analysis of thick shell panels which is subjected to axial tension. Employing the principle of minimum total potential energy, the local governing equations of thick panel which is subjected to axial extension are obtained. An analytical method is developed for solution of the governing equations for various edge conditions. The governing equations are solved for free and simply supported edge conditions. The interlaminar stresses in the panel are investigated by means of Hooke's law and also by means of integration of the equilibrium equations of elasticity. Dependency of the result upon the number of numerical layers in the layerwise theory (LWT) is studied. The accuracy of the numerical results is validated by comparison with the results of the finite element method and with other available results in the open literature and good agreement is seen between the results. Numerical results are then presented for the distribution of interlaminar normal and shear stresses within the symmetric and un-symmetric cross-ply thick panels with free and simply supported boundaries. The effects of the geometrical parameters such as radius to thickness and width to thickness ratio are investigated on the distribution of the interlaminar stresses in thick panels.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.363-368
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• 2001

Abutments in Kumdang bridge are massive concrete structures of which total height is l0m, length is 30m, and width is 7m. Therefore, there is every probability that early age thermal cracking such as hydration heat occur. We measure heat of hydration, strains of rebar, and stresses of concrete abutment during construction. Using analysis of measuring data, we examine thermal stresses, and make use of results as method which control thermal cracking. Finally, we develope thermal stress analysis program which have pre/post processor to be easy of accessing and the usefulness of that is estimated through comparison of results.

• The Journal of Advanced Prosthodontics
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• v.13 no.2
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• pp.79-88
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• 2021

Purpose. To assess peri-implant stress distribution using finite element analysis in implant supported fixed partial denture with occlusal schemes of cuspally loaded occlusion and implant protected occlusion. Materials and methods. A 3-D finite element model of mandible with D2 bone with partially edentulism with unilateral distal extension was made. Two Ti alloy identical implants with 4.2 mm diameter and 10 mm length were placed in the mandibular second premolar and the mandibular second molar region and prosthesis was given with the mandibular first molar pontic. Vertical load of 100 N and and oblique load of 70 N was applied on occlusal surface of prosthesis. Group 1 was cuspally loaded occlusion with total 8 contact points and Group 2 was implant protected occlusion with 3 contact points. Results. In Group 1 for vertical load, maximum stress was generated over implant having 14.3552 Mpa. While for oblique load, overall stress generated was 28.0732 Mpa. In Group 2 for vertical load, maximum stress was generated over crown and overall stress was 16.7682 Mpa. But for oblique load, crown stress and overall stress was maximum 22.7561 Mpa. When Group 1 is compared to Group 2, harmful oblique load caused maximum overall stress 28.0732 Mpa in Group 1. Conclusion. In Group 1, vertical load generated high implant stress, and oblique load generated high overall stresses, cortical stresses and crown stresses compared to vertical load. In Group 2, oblique load generated more overall stresses, cortical stresses, and crown stresses compared to vertical load. Implant protected occlusion generated lesser harmful oblique implant, crown, bone and overall stresses compared to cuspally loaded occlusion.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.3
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• pp.457-478
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• 1992

Electrical resistance strain gauges, brittle-coatings, Moir'e fringe analysis, photoelasticity methods, etc, have been employed in the study of stress analysis and three-dimensional photoelasticity method used in this experiment. The author fabricated a total of 24 samples of maxillary and mandibular edentulous ridges with normal and sharp shapes using epoxy resin, one of the photoelastic materials. In addition, complete denture made from artificial resin teeth in other twoo sizes, large and medium size, were affixed to the specimens and attached to an articulator. The following results were attained by cutting 9 slice specimens into 6mm thick portions, in accordance with the three dimensional photoelastic stress freezing method, to analyze stress distribution status under specific static loading in the central, lateral and protrusive occlusions of the shape of edentulous ridge. 1. In the case of central occlusion, when complete resin artificial teeth in large and medium sizes were used on normal and sharp alveolar ridges, high stress distribution was broadly shown in the labio-buccal sides, and low and concentrated in the lingual sides, in all cases. Generally, the highest stresses were shown at the top of the alveolus, or at 2mm below the top of the alveolus, particularly in the specimen 2, 3, and stresses were more or less the same in the symmetrical right and left sides. 2. In the case of lateral occlusion, when the same load was applied, high stresses were shown broadly at the working sides in both the labio-buccal and lingual sides, and low and concentrated at the balanced sides. The highest stresses were shown in the top of the alveolus on the working sides in specimen 2 portion, and the lowest stresses at the balanced sides in specimen 6, slightly higher stresses were shown at retromolar parts in the balanced sides. 3. In the case of protrusive occlusion, high stresses were broadly shown at the labio-buccal sides, and slightly higher stresses at the top 2, 4, and 6mm parts of the alveolus with concentration. The highest stresses were shown in specimen No. 5 and the lowes stresses in specimen 1, 9 and stresses were more of less the same at the symmetrical right and left sides.

• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.255-270
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• 1991

In recent years. finite element methods have been used with increasing effectiveness in analysis of displacements and stresses within soil masses. However, one of the weakest links in the analytical representations used in these methods is the models of the material behaviour. Herein is discribed a modification to the finite element methods that allows solution problems with realistic stress-strain relation for soils. A finite element program for the precision prediction of the stress distribution within foundation has been developed using the elasto-plastic Work-Hardening model. The developed program is verified by comparing the results of this study with the tested results for Sacramento river sand. The main results obtained from the numerical examples are as follows: The vertical total stress increments are insensitive to drainage and constitutive equation of materials. The horizontal total stress increments are considerably affected by the drainage and constitutive equation of materials. The maximum shear stresses are affected by the drainage only in elasto-ptastic meterirals. The excess pore water pressures and the volumetric strains not only are considerably affected by the constitutive equation of materials. but also have almost similar distribution.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.45-53
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• 1998

A method to predict the creep behavior of fiber-reinforced ceramic composites at high temperatures was suggested based on finite element modeling using constituent creep equations of fiber and matrix and showed good agreement with the experimental results. The effects of matrix creep behavior, fiber volume fraction, and residual stresses on the composite creep behavior were also investigated. The results showed that the primary behavior of composites was greatly affected by that of matrix but post-primary behavior was governed by fiber creep characteristics. The increase of fiber volume fraction from 15 vol% to 30 vol% caused the 50% and 40% decrease of steady-state creep rates and total creep strains at $1200^{\circ}C$, 180MPa, respectively. Feasible compressive residual stresses in the matrix caused by different thermal expansion coefficients between the fiber and the matrix could significantly reduce total creep strains of the composite. The creep deformation mechanism in the fiber-reinforced ceramic composites could be explained by the stress transfer and redistribution in the fiber and matrix due to different creep characteristics of its constituents.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1157-1164
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• 2007

Ceramic honeycomb structures have performed successfully as catalyst supports for meeting hydrocarbon, carbon monoxide and nitrous emissions standards for gasoline-powered vehicles. Three-way catalyst converter has to withstand high temperature and thermal stress due to pressure fluctuations and vibrations. Thermal stress constitutes a major portion of the total stress which the ceramic catalyst support experiences in service. In this study, temperature distribution was measured at ceramic catalyst supports. Thermal durability was evaluated by power series dynamic fatigue damage model. Radial temperature gradient was higher than axial temperature gradient. Thermal stresses depended on direction of elastic modulus. Axial stresses are higher than tangential stresses. Tangential and axial stresses remained below thermal fatigue threshold in all engine operation ranges.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1844-1851
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• 1997

Displacement fields and interface stresses are obtained by modifying the potential energy functional with a penalty function which enforces the continuity of stresses at the interface of two-materials. Based on the displacement field and the interface stresses, a new methodology to generate a continuous stress field over the entire domain including the interface of the dissimilar materials has been proposed by combining the L$^{2}$ projection method of stress-smoothing and the Loubignac's iterative method of improving the displacement field. Stress analysis was carried out on two examples which are made of highly dissimilar materials. As a result of the analysis, it is found that the proposed method provides improved continuity of the stress field over the entire domain as well as predicting accurate nodal stresses at the interface. In contrast, the conventional displacement-based finite element method provides significant stress discontinuties at the interfaces. In addition, it was found that the total strain energy evaluated from the improved continuous stress field converge to the exact value as increasing the number of iterations in the proposed method.

• Steel and Composite Structures
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• v.7 no.1
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• pp.1-18
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• 2007

Additional cutouts in the floorbeam webs of orthotropic plated bridge decks relieve the highly stressed lower flange of the ribs passing through these floorbeam webs from possible fatigue damage. Conversely, the floorbeam webs themselves suffer from high stress concentrations, especially along the free edges of the additional cutouts. These stresses result from a combination of direct introduction of vertical traffic loads in the weakened web and from the truss action of the floorbeam. The latter differs from a simple beam action due to the presence of the openings and corresponds more to the behaviour of a Vierendeel truss. Close assessment of the appearing stresses, highly relevant for fatigue resistance, requires the use of elaborate finite element modelling. However, a full finite element analysis merely provides the results of total stresses, leaving the researcher or designer the difficult task of finding the origin of these stress components. This paper presents a calculation method for cutout stresses based on a combination of a framework analysis and a two dimensional finite element analysis of much smaller parts of the floorbeam. This method provides more insight in the origin of the stress components, as well as it simplifies any comparison of different additional cutout geometries, independent of the floorbeam topology.