This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying mica contents by mass of 5...This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying mica contents by mass of 5%,10%,15%,20%,25%and 30%,to artificially prepare various micaceous clay blends.The preliminary testing phase included consistency limits and standard Proctor compaction tests.The primary testing program consisted of unconfined compression(UC),direct shear(DS)and scanning electron microscopy(SEM)tests.The test results showed that the liquid and plastic limits exhibited a linear,monotonically increasing trend with increase in mica content.The rate of increase in the plastic limit,however,was found to be greater than that of the liquid limit,thereby leading to a gradual transition towards a non-plastic,cohesionless character.The soft,spongy fabric and high water demand of the mica mineral led to higher optimum water contents and lower maximum dry unit weights with increasing mica content.Under low confinement conditions,i.e.the UC test and the DS test at low normal stresses,the shear strength was adversely affected by mica.However,the closer packing of the clay and mica components in the matrix under high confinement conditions offsets the adverse effects of mica by inducing frictional resistance at the shearing interface,thus leading to improved strength resistance.展开更多
Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ monitoring.An ultra-compact high-...Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ monitoring.An ultra-compact high-precision on-chip interrogator is proposed based on a tailored arrayed waveguide grating(AWG)on a silicon-on-insulator(SOI)platform.The on-chip interrogator enables continuous wavelength interrogation from 1544 nm to 1568 nm with the wavelength accuracy of less than 1 pm[the root-mean-square error(RMSE)is 0.73 pm]over the whole wavelength range.The chip loss is less than 5 dB.The 1×16 AWG is optimized to achieve a large bandwidth and a low noise level at each channel,and the FBG reflection peaks can be detected by multiple output channels of the AWG.The fabricated AWG is utilized to interrogate FBG sensors through the center of gravity(CoG)algorithm.The validation of an on-chip FBG interrogator that works with sub-picometer wavelength accuracy in a broad wavelength range shows large potential for applications in miniaturized fiber optic sensing systems.展开更多
Dear Editor,Circadian rhythms are the periodic turmover of biological behaviors and physiological functions of many organisms(Allada and Bass,2021).In mammals,circadian rhythms are maintained by the clock system,invol...Dear Editor,Circadian rhythms are the periodic turmover of biological behaviors and physiological functions of many organisms(Allada and Bass,2021).In mammals,circadian rhythms are maintained by the clock system,involving central clock in suprachiasmatic nucleus and peripheral clock in organs like intestine;and at cellular level a cell-autonomous transcriptional and translational feedback loop involving clock genes like BMAL1(brain and muscle ARNT-Like 1,also known as ARNTL),CLOCK(clock circadian regulator),PER1/2/3(period circadian regulator 1/2/3)and CRY1/2(cryptochrome circadian regulator 1/2)(Allada and Bass,2021).展开更多
The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution.In this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is propose...The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution.In this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is proposed to probe into failure mechanism evolutions for disc specimens upon loading.The tensile damage model and the Drucker-Prager model are used to calculate the tensile failure and shear failure of the material,respectively.It is concluded that for flaw-unfilled disc specimens,the crack coalescence mechanism in the rock bridge area is affected by the flaw inclination angle and the material property.Considering disc specimens with filled flaws,the incremental rate of tensile damage grows more rapidly when the disc and filling material have a closer ratio of tensile strength to cohesion,which makes the entire specimen response greater brittleness.Furthermore,with the increasing non-uniformity of filling distribution,the incremental rate of tensile-activated damage decreases and the disc specimen performs more ductile.Besides,the influence of the fillings is greater when the flaw inclination angle is approaching 45°.It is proved that the proposed SPH method can be used to simulate the failure mechanism evolution of rocks,which lays a foundation for the study of more complex rock failure.展开更多
Mechanical biological treatment(MBT)technology has attracted increasing attention because it can reduce the volume of waste produced.To deal with the current trend of increasing waste,MBT practices are being adopted t...Mechanical biological treatment(MBT)technology has attracted increasing attention because it can reduce the volume of waste produced.To deal with the current trend of increasing waste,MBT practices are being adopted to address waste generated in developing urban societies.In this study,a total of 20 specimens of consolidated undrained triaxial tests were conducted on waste obtained from the Hangzhou Tianziling landfill,China,to evaluate the effect of loading rate on the shear strength parameters of MBT waste.The MBT waste samples exhibited an evident strain-hardening behavior,and no peak was observed even when the axial strain exceeded 25%.Further,the shear strength increased with an increase in the loading rate;the effect of loading rate on shear strength under a low confining pressure was greater than that under a high confining pressure.Furthermore,the shear strength parameters of MBT waste were related to the loading rate.The relationship between the cohesion,internal friction angle,and logarithm of the loading rate could be fitted to a linear relationship,which was established in this study.Finally,the ranges of shear strength parameters cohesion c and effective cohesion c′were determined as 1.0–8.2 kPa and 2.1–14.9 kPa,respectively;the ranges of the internal friction angleφand effective internal friction angleφ’were determined as 16.2°–29°and 19.8°–43.9°,respectively.These results could be used as a valuable reference for conducting stability analyses of MBT landfills.展开更多
基金made possible through the provision of an Australian Government Research Training Program Scholarship
文摘This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying mica contents by mass of 5%,10%,15%,20%,25%and 30%,to artificially prepare various micaceous clay blends.The preliminary testing phase included consistency limits and standard Proctor compaction tests.The primary testing program consisted of unconfined compression(UC),direct shear(DS)and scanning electron microscopy(SEM)tests.The test results showed that the liquid and plastic limits exhibited a linear,monotonically increasing trend with increase in mica content.The rate of increase in the plastic limit,however,was found to be greater than that of the liquid limit,thereby leading to a gradual transition towards a non-plastic,cohesionless character.The soft,spongy fabric and high water demand of the mica mineral led to higher optimum water contents and lower maximum dry unit weights with increasing mica content.Under low confinement conditions,i.e.the UC test and the DS test at low normal stresses,the shear strength was adversely affected by mica.However,the closer packing of the clay and mica components in the matrix under high confinement conditions offsets the adverse effects of mica by inducing frictional resistance at the shearing interface,thus leading to improved strength resistance.
基金This work wasssupported by the National Natural Science Foundation of China(Grant Nos.62020106002 and 61735017)Innovation Project of Zhejiang Laboratory(Grant No.2021MG0AL01)+2 种基金the Youth Foundation of Zhejiang Laboratory(Grant No.2020MC0AA08)Major Scientific Research Project of Zhejiang Laboratory(Grant No.2019MC0AD02)National Key Basic Research Program of China(Grant No.2021YFC2401403).
文摘Miniaturized fiber-Bragg-grating(FBG)interrogators are of interest for applications in the areas where weight and size controlling is important,e.g.,airplanes and aerospace or in-situ monitoring.An ultra-compact high-precision on-chip interrogator is proposed based on a tailored arrayed waveguide grating(AWG)on a silicon-on-insulator(SOI)platform.The on-chip interrogator enables continuous wavelength interrogation from 1544 nm to 1568 nm with the wavelength accuracy of less than 1 pm[the root-mean-square error(RMSE)is 0.73 pm]over the whole wavelength range.The chip loss is less than 5 dB.The 1×16 AWG is optimized to achieve a large bandwidth and a low noise level at each channel,and the FBG reflection peaks can be detected by multiple output channels of the AWG.The fabricated AWG is utilized to interrogate FBG sensors through the center of gravity(CoG)algorithm.The validation of an on-chip FBG interrogator that works with sub-picometer wavelength accuracy in a broad wavelength range shows large potential for applications in miniaturized fiber optic sensing systems.
基金supported by the National Key Research and Development Program of China(2018YFC2000500)the National Natural Science Foundation of China(91857101)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB29020000)the National Natural Science Foundation of China(81922027,81870228,and 81921006)Beijing Natural Science Foundation(Q20031)and the State Key Laboratory of Membrane Biology.
文摘Dear Editor,Circadian rhythms are the periodic turmover of biological behaviors and physiological functions of many organisms(Allada and Bass,2021).In mammals,circadian rhythms are maintained by the clock system,involving central clock in suprachiasmatic nucleus and peripheral clock in organs like intestine;and at cellular level a cell-autonomous transcriptional and translational feedback loop involving clock genes like BMAL1(brain and muscle ARNT-Like 1,also known as ARNTL),CLOCK(clock circadian regulator),PER1/2/3(period circadian regulator 1/2/3)and CRY1/2(cryptochrome circadian regulator 1/2)(Allada and Bass,2021).
基金This work is supported in part by the National Natural Science Foundation of China(No.51779084)。
文摘The mechanical responses and ultimate failure patterns of rocks are associated with the failure mechanism evolution.In this study,smoothed particle hydrodynamics(SPH)method with the mixed-mode failure model is proposed to probe into failure mechanism evolutions for disc specimens upon loading.The tensile damage model and the Drucker-Prager model are used to calculate the tensile failure and shear failure of the material,respectively.It is concluded that for flaw-unfilled disc specimens,the crack coalescence mechanism in the rock bridge area is affected by the flaw inclination angle and the material property.Considering disc specimens with filled flaws,the incremental rate of tensile damage grows more rapidly when the disc and filling material have a closer ratio of tensile strength to cohesion,which makes the entire specimen response greater brittleness.Furthermore,with the increasing non-uniformity of filling distribution,the incremental rate of tensile-activated damage decreases and the disc specimen performs more ductile.Besides,the influence of the fillings is greater when the flaw inclination angle is approaching 45°.It is proved that the proposed SPH method can be used to simulate the failure mechanism evolution of rocks,which lays a foundation for the study of more complex rock failure.
基金funded by the National Natural Science Foundation of China(Nos.51978625 and 51678532)the Zhejiang Provincial Natural Science Foundation of China(No.LZ21E080003)。
文摘Mechanical biological treatment(MBT)technology has attracted increasing attention because it can reduce the volume of waste produced.To deal with the current trend of increasing waste,MBT practices are being adopted to address waste generated in developing urban societies.In this study,a total of 20 specimens of consolidated undrained triaxial tests were conducted on waste obtained from the Hangzhou Tianziling landfill,China,to evaluate the effect of loading rate on the shear strength parameters of MBT waste.The MBT waste samples exhibited an evident strain-hardening behavior,and no peak was observed even when the axial strain exceeded 25%.Further,the shear strength increased with an increase in the loading rate;the effect of loading rate on shear strength under a low confining pressure was greater than that under a high confining pressure.Furthermore,the shear strength parameters of MBT waste were related to the loading rate.The relationship between the cohesion,internal friction angle,and logarithm of the loading rate could be fitted to a linear relationship,which was established in this study.Finally,the ranges of shear strength parameters cohesion c and effective cohesion c′were determined as 1.0–8.2 kPa and 2.1–14.9 kPa,respectively;the ranges of the internal friction angleφand effective internal friction angleφ’were determined as 16.2°–29°and 19.8°–43.9°,respectively.These results could be used as a valuable reference for conducting stability analyses of MBT landfills.
