• Journal of the Korean Geotechnical Society
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• v.27 no.3
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• pp.63-73
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• 2011

The behavior of laterally cyclic loaded piles is affected by the magnitude and number of cycles of cyclic lateral loads as well as loading method (1-way or 2-way loading). In this study, calibration chamber tests were carried out to investigate the effects of loading method of cyclic lateral loads on the behavior of piles driven into sand. Results of the chamber tests show that the permanent lateral displacement of 1-way cyclic loaded piles is developed in the same direction as the first loading, whereas that of 2-way cyclic loaded piles is developed in the reverse direction of the first loading. 1-way cyclic lateral loads cause a decrease of the ultimate lateral load capacity of piles, and 2-way cyclic lateral loads cause an increase of the ultimate lateral load capacity of piles. The change of ultimate lateral load capacity with loading method of cyclic lateral loads increases with increasing number of cycles. It is also observed that the 1-way cyclic loads generate greater maximum bending moment than 2-way cyclic loads for piles in cyclic loading step and generates smaller maximum bending moment for piles in the ultimate state. It can be attributed to the difference in compaction degree of the soil around the piles with loading method of cyclic lateral loads. In addition, it is founded that 1-way and 2-way cyclic lateral loads cause a decrease in the maximum bending moment of piles in the ultimate state compared with that of piles subjected to only monotonic loads.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.9-20
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• 2003

Using a nickel-chrome casting alloy called 'Rexillium V' which is also available as base metal alloy for dental ceramic crown, 4 types of mixtures(A, B, C, D) with old and new metal were prepared for cyclic casting. The results of cyclic casting can be outlined as follows: 1. For Vickers hardness after casting, specimen A and D tended to have lower hardness in the course of cyclic casting, while specimen B and C tended to higher hardness. 2. The results of X-ray diffraction analysis showed that major crystal phase contained nickelchrome compounds and carbide. 3. The observation results of SEM photographs after cyclic casting show that there was a significant tendency to have similar structures among experimental groups. 4. The results of EDX analysis after cyclic casting showed that there were little differences in chemical composition between parent metal and base metal alloy. Although industrial nickel-chrome cast alloy did not show any significant change in material properties even through cyclic casting over several times, it is recommended that more there be more in-depth studies on how to detect any potential corrosion, discoloration and toxication of dental ceramic crown implanted in patient's oral cavity.

• Geotechnical Engineering
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• v.10 no.4
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• pp.119-132
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• 1994

Undrained cyclic triaxial tests were performed on silt contained in the sand in order to investigate the effect of silt contents on the liquefaction strength and shear characterist ifs of the sand. As the result of this experiment, the weakest percentage of silt contained in the sand was 30% for all the relative density considered in the test. Also, the same bests were performed to find the effect of cyclic speed applied ranging from 0.1Hz to 5Hz on the liquefaction strength. The more the silt is contained in the sand, the greater the liquefaction strength was affected by cyclic speed, While the silt -containing sand was far less influenced by the cyclic speed than clay containing sand. These results are believed to be caused by the change of pore water pressure of the effective stress path.

• Resources Recycling
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• v.10 no.3
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• pp.29-36
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• 2001

Cyclic voltammetry has been applied in the basic studies for the treatment and recovery of heavy metal component contained in wastewater by electrochemical reduction. The electrochemical behaviors of zinc ion for zinc metal electrode and carbon elec-trode were characterized by voltammograms and it was showed that zinc ions were reduced to metallic form below -0.76 V vs SHE. The change in the features of crystalline form of metallic zinc upon oxidation and reduction reaction was observed by X-ray diffraction method and the Am analysis verified that zinc ions were reduced to metal on copper plate. The results of this study were regarded to be important and meaningful in the treatment of heavy metal containing wastewater and, as a result, in the obtainment of metallic product by electrochemical method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.1
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• pp.29-43
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• 1998

This study was to investigate the effect of .compressive load and cyclic humidity(2$0^{\circ}C$, 65% and 90% RH) on the physical and mechanical properties of corrugated board. Corrugated boards in the study were under compressive load and under cyclic humidity, and their properties were compared to those without load. Results were summarized as follows ; 1 Statistically significant correlation was shown between the ring crush of the boards and the compressive strength of cylinder specimen made from the boards. So we could study the compressive behavior of board with cylinder specimen. 2. The boards under the compressive load increased their moisture content and thickness much more than those without load both in constant and in cyclic RH. 3. The compressive and tensile strength of board samples were inversely and closely proportional to the sheet moisture content regardless of their load and humidity history. 4. The moisture content did not show any significant proportionality to the change of burst strength of boards within this experiment. 5. Board reconditioning in standard condition led to the recovery of the strength loss that had occurred under various load and humidity condition. 6. The handsheets prepared from the boards that had experienced compressive load and cyclic humidity, and those with no-load and 65% RH did not show any significant difference in strength properties. No physical damage or load-carrying properties of the wood fiber were observed by the compressive load and cyclic humidity history.

• Steel and Composite Structures
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• v.43 no.5
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• pp.673-688
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• 2022

Post-earthquake fire is a major threat since most structures are designed allowing some damage during strong earthquakes, which will expose a more vulnerable structure to post-earthquake fire compared to an intact structure. A series of experimental research on steel-concrete composite beam-to-column joints subjected to fire after cyclic loading has been carried out and a clear reduction of fire resistance due to the partial damage caused by cyclic loading was observed. In this paper, by using ABAQUS a robust finite element model is developed for exploring the performance of steel-concrete composite joints in post-earthquake fire scenarios. After validation of these models with the previously conducted experimental results, a comprehensive numerical analysis is performed, allowing influential parameters affecting the post-earthquake fire behavior of the steel-concrete composite joints to be identified. Specifically, the level of pre-damage induced by cyclic loading is regraded to deteriorate mechanical and thermal properties of concrete, material properties of steel, and thickness of the fire protection layer. It is found that the ultimate temperature of the joint is affected by the load ratio while fire-resistant duration is relevant to the heating rate, both of which change due to the damage induced by the cyclic loading.

• Geomechanics and Engineering
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• v.35 no.6
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• pp.627-636
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• 2023

The essence of subgrade mud pumping under train load is the migration of fine particles in subgrade soil. The migration of fine particles will change the pore structure of overlying ballast, thus affecting the mechanical properties and hydraulic properties of ballast layer. It is of great theoretical significance and engineering value to study the effect of fine particle migration on the pore structure of ballast layer under cyclic loading. In this paper, a tailor-made subgrade mud pumping test model and an X-ray computed tomography (CT) scanning equipment were used to study the influence of migration of fine particles in subgrade soil on the pore parameters (plane porosity, volume porosity, pore distribution and pore connectivity) of overlying ballast under cyclic loading. The results show that the compression of ballast pores and the blockage of migrated fine particles make the porosity of ballast layer decreases gradually. And the percentage of small pores in ballast layer increases, while the percentage of large pores decreases; the connectivity of pores also gradually decreases. Based on the test results, an empirical model of ballast porosity evolution under cyclic loading is established and verified.

• The Korean Journal of Pharmacology
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• v.19 no.1
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• pp.93-99
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• 1983

Hydrocortisone 5 mg/kg which exerts minimal effect on the renal function and furosemide 1 mg/kg which induces moderate amount of diuresis were injected intraperitoneally to study their effects on the renal cyclic nucleotides content in rats. 1) The renal tissue levels of cAMP were significantly increased by administration of hydrocortisone, but there was no significant change in the furosemide group compared with that of saline treated control group. Moderate elevation in renal cAMP level was noted by the combined administration of hydrocortisone and furosemide, but this elevation was less than that of hvdrocortisone treated group. 2) The renal cGMP level did not show nay remarkable change after the administration of hydrocortisone, however, there were a significant increase by the administration of furosemide alone or combination of both drugs. The level of renal cGMP was higher and maintained longer in the combined treated group than furosemide treated group. The result of this experiment indicates that the potentiating effect of hydrocortisone on the diuretic action of furosemide nay be related to the renal levels of cGMP rather than that of cAMP.

• Geomechanics and Engineering
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• v.37 no.4
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• pp.383-393
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• 2024

Monopile foundations of offshore wind turbines embedded in soft clay are subjected to the long-term cyclic lateral loads induced by winds, currents, and waves, the vibration of monopile leads to the accumulation of pore pressure and cyclic strains in the soil in its vicinity, which poses a threat to the safety operation of monopile. The researchers mainly focused on the hysteretic stress-strain relationship of soft clay and kinds of stiffness degradation models have been adopted, which may consume considerable computing resources and is not applicable for the long-term bearing performance analysis of monopile. In this study, a modified cyclic stiffness degradation model considering the effect of plastic strain and pore pressure change has been proposed and validated by comparing with the triaxial test results. Subsequently, the effects of cyclic load ratio, pile aspect ratio, number of load cycles, and length to embedded depth ratio on the accumulated rotation angle and pore pressure are presented. The results indicate the number of load cycles can significantly affect the accumulated rotation angle of monopile, whereas the accumulated pore pressure distribution along the pile merely changes with pile diameter, embedded length, and the number of load cycles, the stiffness of monopile can be significantly weakened by decreasing the embedded depth ratio L/H of monopile. The stiffness degradation of soil is more significant in the passive earth pressure zone, in which soil liquefaction is likely to occur. Furthermore, the suitability of the "accumulated rotation angle" and "accumulated pore pressure" design criteria for determining the required cyclic load ratio are discussed.

• Archives of Pharmacal Research
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• v.16 no.1
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• pp.71-74
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• 1993

The protective effect of adenosine triphosphate (ATP) on gastic ulcer induced in rats has been studied. Gastic ulceration was induced by hypothemic restraint stress or dicolofenac sodium. Gastic acid secretion and mucosal injury produced by the hypothemic restraint stress was greater as compared with those produced by diclofenac sodifum. ATP significantly reduced area of injury, however, increased cyclic adenosine monophosphate (cATP) content. Administration of dipyridamole along with ATP did not change the total lesion area in both models when compared to ATP alone. Aminophyline antagonized antagonized the protective effect of ATP on the injured area. Famotidine was found to be effective in reducing gastric acid output as well as the total injured area without any change in cAMP content when given along with ATP.