• Transactions of Materials Processing
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• v.9 no.4
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• pp.372-378
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• 2000

A process model including the effects of both the texture development and ductile damage evolution In plane strain rolling is presented. In this process model, anisotropy from deformation texture and deterioration of mechanical properties due to growth of micro voids are directly coupled Into the virtual work expressions for the momentum and mass balances. Special treatments in obtaining the initial values of field variables in the nonlinear simultaneous equations for the anisotropic, dilatant viscoplastic deformation are also given. Mutual effects of the texture development and damage evolution during plate rolling are carefully examined in terms of the distribution of strain components, accumulated damage, R-value as well as yield surfaces.

• Geomechanics and Engineering
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• v.12 no.4
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• pp.611-626
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• 2017

The research reported herein is concerned with the model testing of piles socketed in soft rock which was simulated by cement, plaster, sand, water and concrete hardening accelerator. Model tests on a single pile socketed in simulated soft rock under axial cyclic loading were conducted and the bearing capacity and accumulated deformation characteristics under different static, and cyclic loads were studied by using a device which combined oneself-designed test apparatus with a dynamic triaxial system. The accumulated deformation of the pile head, and the axial force, were measured by LVDT and strain gauges, respectively. Test results show that the static load ratio (SLR), cyclic load ratio (CLR), and the number of cycles affect the accumulated deformation, cyclic secant modulus of pile head, and ultimate bearing capacity. The accumulated deformation increases with increasing numbers of cycles, however, its rate of growth decreases and is asymptotic to zero. The cyclic secant modulus of pile head increases and then decreases with the growth in the number of cycles, and finally remains stable after 50 cycles. The ultimate bearing capacity of the pile is increased by about 30% because of the cyclic loading thereon, and the axial force is changed due to the applied cyclic shear stress. According to the test results, the development of accumulated settlement is analysed. Finally, an empirical formula for accumulated settlement, considering the effects of the number of cycles, the static load ratio, the cyclic load ratio and the uniaxial compressive strength, is proposed which can be used for feasibility studies or preliminary design of pile foundations on soft rock subjected to cyclic loading.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.195-204
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• 2004

A series of constant creep and repeated creep tests are performed to investigate the behavior of visco-elasto-plastic materials of chemical grouted sands. In the result of constant creep test, the material exhibits three types of shear strain : elastic, plastic, viscoelastic. The elastic, plastic and viscoelastic strains are linear, i.e., the strains are proportional to the stresses for loading. Good agreement is found between the predicted viscoelastic and test results by the power law and the generalized model. In the repeated creep test, the instantaneous recoverable strain is time-independent and the magnitude of accumulated plastic strain increases with number of cycles. Also it is seen that the accumulated plastic strains are approximately proportional to stress. There are no significant differences between test results predicted values for first cycle, and the differences increase relatively insignificantly with number of cycles.

• The Korean Journal of Zoology
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• v.25 no.2
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• pp.93-106
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• 1982

Proteins, which may be closely related to differentiation of a cell group into a predestined fate, were investigated using imaginal discs of a wing mutant, vestigial of Drosophila melanogaster. The wing discs of the mutant fail to differentiate into normal wings, even though the third instar larvae form wing discs, which are very similar to those of the normal strain in size and shape. Patterns of proteins of accumulated or synthesized in the discs of the third instar larvae of the normal and mutant strains were analyzed by acrylamide gel electrophoresis. The patterns of accumulated proteins were found to be slightly different between two strains in quantity rather than in quality. The patterns of proteins synthesized at various times of the third instar were found to be very similar to each other, even though there were a few proteins specific to the normal or to the mutant strain.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1259-1265
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• 2010

The filamentous cyanobacterium Arthrospira platensis strain MMG-9 was isolated from a rice field. The ability of this strain to synthesize the bioactive compound indole-3-acetic acid (IAA) was demonstrated. IAA was extracted from the culture of A. platensis strain MMG-9 and its identity was confirmed by thin-layer chromatography (TLC) as well as by high-performance liquid chromatography (HPLC). The IAA precursor L-tryptophan was required for IAA biosynthesis. Released IAA increased with the increase of the initial concentration of L-tryptophan in the medium and with the incubation time. A. platensis strain MMG-9 accumulated more IAA than it released into the medium. The bioactivity of the secreted IAA was shown by its effect on the formation of roots by Pisum sativum. There was a significant positive effect of the supernatant of cultures of A. platensis strain MMG-9 on the number of lateral roots of P. sativum, whereas a negative effect on root length was observed.

• Transactions of Materials Processing
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• v.32 no.1
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• pp.35-40
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• 2023

In the case of a wire with a very fine diameter during the multi-stage drawing process, the heterogeneity of the deformation in the radial direction tends to develop strongly as the amount of deformation is accumulated. It is known that the heterogeneity of deformation in the radial direction of the wire is closely related to the process parameters during the multi-stage drawing process. In this study, finite element analysis (FEA) was used to theoretically examine the effect of friction between the surface of the wire and the drawing die during the multi-stage drawing process of Cu-0.2wt%Mg alloy on the deformation heterogeneity developed in the radial direction of the wire. The distribution of effective strain, radial strain, circumferential strain, and shear strain developed in the radial direction of the wire during the multi-stage drawing process was analyzed while changing the friction coefficient, and the results were analyzed and compared for each path and position. The FEA results revealed that the shear strain developed in the radial direction of the wire during the multi-stage drawing process of Cu-0.2wt%Mg alloy showed the most non-uniform distribution and was also severely affected by the friction coefficient.

• Korean Journal of Microbiology
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• v.20 no.4
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• pp.195-200
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• 1982

Rhizobium japonicum was isolated from the nodule of soybean root grown at the reclaimed tidal land in Kang-Wha island. The effect of pH and salt concentration to the viability of the isolated strain were examined in relationship between microbial growth and accumulation of PHB. Optimal pH value for the good viability of the isolated strain was 7.0 and also, at 5.0 and 6.0 viability was favorable to large extent, but 9.0 was unfavorable. Examined the effect of salt concentration treated two times as of the salinity in the reclaimed tidal land, viability of the isolated strain showed about 30 to 40%. And also in treatment with NaCl(40g/l) whatever the pH value adopted, viability was mostly less than 10%. The amount of accumulated PHB was relatively high at low pH value(5-6) and at high salt concentrration, respectively.

• Journal of Microbiology
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• v.34 no.3
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• pp.289-293
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• 1996

A cadimium-resistant strain isolated from Anyang stream, Azomonas agilis PY101 exhibited strong resistance to 1000 ppm of cadmium ion $(Cd^{2+})$. A agilis PY101 also exhibited resistance to various antibiotics, such as amoxicillin, amplicillin, bacitracin, cefazolin, erythromycin, penicillin, tetracycline, and vancomycin. In the presence of $Cd^{2+}$, the growth of A. agilis PY101 started after an extended lag phase and produced a green-fluorescent pigment induced by cadmium. The dramatic decrease (approximately 400ppm) of concentration of $cd^{2+}$ in the culture medium during the growth phase of A. agilis PY101 was confirmed by the inductively coupled plasma-atomic emission spectrophotometer. Transmission electron microscopic analysis revealed that A. agilis PY 101 actively accumulated $Cd^{2+}$ in the cytoplasm.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.311-316
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• 2008

Ratcheting is a cyclic accumulation of strain under a cyclic loading. It is a kind of mechanisms which generate cracks in rail steels. Though some experimental and numerical study has been performed, modeling of ratcheting is still a challenging problem. In this study, an elastic-plastic constitutive equation with non-linear kinematic hardening equation was applied. Contact stresses in wheel-rail were analyzed. Under the tangential stress of the contact stresses, a cyclic stress-strain relation was obtained by using the model. A constant ratcheting strain per cycle was accumulated.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.112-115
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• 1972

In the cource of investigation on L-glutamic acid production, acetate assimilating bacteria were isolated from natural sources. Among them, the strain No. 1214 was selected and characterized as a strain related to the genus Brevibacterium according to the standard method of taxonomy. This strain could grow in the acetate medium and accumulated a considerable amount of L-glutamic acid (22 g/L).