In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural ...In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element method.The simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial stress.Furthermore,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box girder.The results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle load.However,the inclusion of residual stress leads to the propagation of these cracks.When considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual bridges.In the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I cracks.Conversely,when residual stress is considered,these cracks become I-II composite cracks.Residual stress significantly alters the cumulative energy release rate of the three fracturemodes.Therefore,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.展开更多
The purposes of this study are to prepare the generic extended release tablet of potassiumchloride(PC) 600 mg and to compare the absorption of potassium ion from the experimen-tal tablets to that of Kaleorid? LP 600 m...The purposes of this study are to prepare the generic extended release tablet of potassiumchloride(PC) 600 mg and to compare the absorption of potassium ion from the experimen-tal tablets to that of Kaleorid? LP 600 mg(Leo Pharmaceutical Products, Denmark). Car-nauba wax was used as retardant in the matrix core tablets. The core tablets were coatedwith blends of ethyl cellulose(EC) and hydroxypropyl methyl cellulose(HPMC) to modulatethe drug release. Results of a selective two-level, three-factor experiment design revealedthat a blend of 41.75% of EC and 58.25% of HPMC at 4.5% weight gained could produce thecoated tablets having dissolution profiles similar to those of Kaleorid?. A two-treatment,two-period, two-sequence crossover bioequivalence study was carried out on 24 healthyvolunteers to compare the absorption of potassium ion from experimental tablets to thatfrom Kaleorid?. The potassium ion in the urine was measured by a selective electrode of theADVIA 1650 system(Bayer) and used to calculate cumulative urinary excretion and urinaryexcretion rate. Results of 90 percent confidence interval analysis showed that the limits fornatural log-transformed cumulative urinary potassium excretion(Ln Ae 0-24) of test productwere in the range of 3.73–3.79 mEq, corresponding to 99.08%–100.92% of Kaleorid ?, respec-tively, and the limits for natural log-transformed maximal potassium excretion rate( R max) oftest product were in the range of 1.72–1.82 mEq/h, corresponding to 97.34%–102.66% of refer-ence product, respectively. Both of them fell within the bioequivalence interval(80%–125%)of reference product, proving that experimental product is bioequivalent to Kaleorid ?.展开更多
基金supported by a grant from the Key Technologies Research and Development Program(No.2021YFF0602005)Jiangsu Key Research and Development Plan(Nos.BE2022129,BE2022134)the Fundamental Research Funds for the Central Universities(Nos.2242022k30031,2242022k30033),which are gratefully acknowledged.
文摘In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element method.The simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial stress.Furthermore,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box girder.The results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle load.However,the inclusion of residual stress leads to the propagation of these cracks.When considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual bridges.In the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I cracks.Conversely,when residual stress is considered,these cracks become I-II composite cracks.Residual stress significantly alters the cumulative energy release rate of the three fracturemodes.Therefore,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.
基金Financial support for bioequivalence study from The Department of Science and Technology (grant number 209/HDSKHCN) of Ho chi Minh city (DOST)
文摘The purposes of this study are to prepare the generic extended release tablet of potassiumchloride(PC) 600 mg and to compare the absorption of potassium ion from the experimen-tal tablets to that of Kaleorid? LP 600 mg(Leo Pharmaceutical Products, Denmark). Car-nauba wax was used as retardant in the matrix core tablets. The core tablets were coatedwith blends of ethyl cellulose(EC) and hydroxypropyl methyl cellulose(HPMC) to modulatethe drug release. Results of a selective two-level, three-factor experiment design revealedthat a blend of 41.75% of EC and 58.25% of HPMC at 4.5% weight gained could produce thecoated tablets having dissolution profiles similar to those of Kaleorid?. A two-treatment,two-period, two-sequence crossover bioequivalence study was carried out on 24 healthyvolunteers to compare the absorption of potassium ion from experimental tablets to thatfrom Kaleorid?. The potassium ion in the urine was measured by a selective electrode of theADVIA 1650 system(Bayer) and used to calculate cumulative urinary excretion and urinaryexcretion rate. Results of 90 percent confidence interval analysis showed that the limits fornatural log-transformed cumulative urinary potassium excretion(Ln Ae 0-24) of test productwere in the range of 3.73–3.79 mEq, corresponding to 99.08%–100.92% of Kaleorid ?, respec-tively, and the limits for natural log-transformed maximal potassium excretion rate( R max) oftest product were in the range of 1.72–1.82 mEq/h, corresponding to 97.34%–102.66% of refer-ence product, respectively. Both of them fell within the bioequivalence interval(80%–125%)of reference product, proving that experimental product is bioequivalent to Kaleorid ?.
