The behavior of soil-structure interface plays a major role in the definition of soil-structure interaction. In this paper a bi-potential surface elasto-plastic model for soil-structure interface is proposed in order ...The behavior of soil-structure interface plays a major role in the definition of soil-structure interaction. In this paper a bi-potential surface elasto-plastic model for soil-structure interface is proposed in order to describe the interface deformation behavior,including strain softening and normal dilatancy. The model is formulated in the framework of generalized potential theory,in which the soil-structure interface problem is regard as a two-dimensional mathematical problem in stress field,and plastic state equations are used to replace the traditional field surface. The relation curves of shear stress and tangential strain are fitted by a piecewise function composed by hyperbolic functions and hyperbolic secant functions,while the relation curves of normal strain and tangential strain are fitted by another piecewise function composed by quadratic functions and hyperbolic secant functions. The approach proposed has the advantage of deriving an elastoplastic constitutive matrix without postulating the plastic potential functions and yield surface. Moreover,the mathematical principle is clear,and the entire model parameters can be identified by experimental tests. Finally,the predictions of the model have been compared with experimental results obtained from simple shear tests under normal stresses,and results show the model is reasonable and practical.展开更多
The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior.Interfaces are considered as thin layers of ...The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior.Interfaces are considered as thin layers of the soil adjacent to structures boundary whose major role is transferring loads from structures to soil masses.An interface model within the bounding surface plasticity framework and the critical state soil mechanics is presented.To this aim,general formulation of the interface model according to the bounding surface plasticity theory is described first.Similar to granular soils,it has been shown that the mechanical behavior of sand-structure interfaces is highly affected by the interface state that is the combined influences of density and applied normal stress.Therefore,several ingredients of the model are directly related to the interface state.As a result of this feature,the model is enabled to distinguish interfaces in dense state from those in loose state and to provide realistic predictions over wide ranges of density and normal stress values.In evaluation of the model,a reasonable correspondence between the model predictions and the experimental data of various research teams is found.展开更多
This paper proposes a new interface constitutive model for fully grouted rock-bolts and cable-bolts based on pull-out test results.A database was created combining published experimental data with in-house tests.By me...This paper proposes a new interface constitutive model for fully grouted rock-bolts and cable-bolts based on pull-out test results.A database was created combining published experimental data with in-house tests.By means of a comprehensive framework,a Coulomb-type failure criterion accounting for friction mobilization was defined.During the elastic phase,in which the interface joint is not yet created,the proposed model provides zero radial displacement,and once the interface joint is created,interface dilatancy is modeled using a non-associated plastic potential inspired from the behavior of rock joints.The results predicted by the proposed model are in good agreement with experimental results.The model has been implemented in a finite element method(FEM)code and numerical simulations have been performed at the elementary and the structural scales.The results obtained provide confidence in the ability of the new model to assist in the design and optimization of bolting patterns.展开更多
In patients suffering from neurogenic detrusor overactivity, continence can be regained by conditional stimulation of the dorsal genital nerve (DGN);that is applying electrical stimulation to the DGN at the onset of a...In patients suffering from neurogenic detrusor overactivity, continence can be regained by conditional stimulation of the dorsal genital nerve (DGN);that is applying electrical stimulation to the DGN at the onset of an involuntary contraction. For this scheme to work, a sensor capable of reliably detecting the onset of bladder contractions is needed. This article reviews the methods proposed for or associated with detection of bladder contractions, and their applicability to onset detection is assessed. Fourteen methods are described in this review;bladder pressure, urethral sphincter EMG and anal sphincter EMG are the most promising options for onset detection. For all three modalities, however, further research is needed before clinical application becomes viable.展开更多
This note establishes a new method that can measure interface dilatation elastic module (ε) and dilatation viscosity (ηd) of all surfactants based on the surface pressure relaxation process. The wide applicability w...This note establishes a new method that can measure interface dilatation elastic module (ε) and dilatation viscosity (ηd) of all surfactants based on the surface pressure relaxation process. The wide applicability was proved with the stability of foam as an example.展开更多
Oil-water interface layers dilatation rheological properties have been measured with the liquid-liquid interface film pressure measurement apparatus, which was based on the principles of Langmuir film balance. Experim...Oil-water interface layers dilatation rheological properties have been measured with the liquid-liquid interface film pressure measurement apparatus, which was based on the principles of Langmuir film balance. Experimental results show that it is possible to form the interface-associated material caused by the attraction of the dispersion forces at the pure alkane-water interface. The type of material is sensitive to the interfacial pressure. Under the influence of the interfacial pressure, the stability of the interface associated materials decreases with the increase of the number of alkane carbons.展开更多
Since its discovery, myosin-binding protein C (cMyBP-C) has become a protein of interest clinically. With emergence of new methodologies and technologies, the structure and functions of cMyBP-C from different aspects ...Since its discovery, myosin-binding protein C (cMyBP-C) has become a protein of interest clinically. With emergence of new methodologies and technologies, the structure and functions of cMyBP-C from different aspects can be studied, enabling us to better understand its involvement in certain cardiac conditions. Studying its kinetics of release and clearance from the circulation and by comparing to other conventional biomarkers, it has been reported that cMyBP-C is eligible to be a novel biomarker for several cardiac conditions. Moreover, studying the genetics and their involvement in pathogenic mechanisms has opened the ideas for potential therapeutic strategies. More and more researches are constantly being done to better understand the role of cMyBP-C in dilated cardiomyopathy (DCM). The importance of cMyBP-C to the heart is still actively being investigated. Its presence is however crucial for sarcomere organization and proper regulation of cardiac contraction during systole and complete relaxation during diastole. Genetic mutation in cMyBP-C has been linked to cardiac conditions including hypertrophic and dilated cardiomyopathies. Around 350 types of mutations have already been documented leading to various cardiac conditions and abnormalities. Analyzing human heart samples has enabled us to better understand the importance of cMyBP-C and how its mutations lead to inherited cardiomyopathies. It is therefore necessary to have an update about the research progress of cMyBP-C in relation to DCM and other cardiac conditions.展开更多
A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having differen...A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h ratios.The model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 e13.5.It was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the rock.The resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression results.Eventually,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test results.The study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.展开更多
基金supported by the National Natural Science Foundation of ChinaYalona River Hydropower Development of Ertan Hydropower Development Company (No.50639050)
文摘The behavior of soil-structure interface plays a major role in the definition of soil-structure interaction. In this paper a bi-potential surface elasto-plastic model for soil-structure interface is proposed in order to describe the interface deformation behavior,including strain softening and normal dilatancy. The model is formulated in the framework of generalized potential theory,in which the soil-structure interface problem is regard as a two-dimensional mathematical problem in stress field,and plastic state equations are used to replace the traditional field surface. The relation curves of shear stress and tangential strain are fitted by a piecewise function composed by hyperbolic functions and hyperbolic secant functions,while the relation curves of normal strain and tangential strain are fitted by another piecewise function composed by quadratic functions and hyperbolic secant functions. The approach proposed has the advantage of deriving an elastoplastic constitutive matrix without postulating the plastic potential functions and yield surface. Moreover,the mathematical principle is clear,and the entire model parameters can be identified by experimental tests. Finally,the predictions of the model have been compared with experimental results obtained from simple shear tests under normal stresses,and results show the model is reasonable and practical.
文摘The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior.Interfaces are considered as thin layers of the soil adjacent to structures boundary whose major role is transferring loads from structures to soil masses.An interface model within the bounding surface plasticity framework and the critical state soil mechanics is presented.To this aim,general formulation of the interface model according to the bounding surface plasticity theory is described first.Similar to granular soils,it has been shown that the mechanical behavior of sand-structure interfaces is highly affected by the interface state that is the combined influences of density and applied normal stress.Therefore,several ingredients of the model are directly related to the interface state.As a result of this feature,the model is enabled to distinguish interfaces in dense state from those in loose state and to provide realistic predictions over wide ranges of density and normal stress values.In evaluation of the model,a reasonable correspondence between the model predictions and the experimental data of various research teams is found.
基金supported by the Research Fund for Coal and Steel(RFCS)in the context of the European project Advancing Mining Support Systems to Enhance the Control of Highly Stressed Ground(AMSSTED)。
文摘This paper proposes a new interface constitutive model for fully grouted rock-bolts and cable-bolts based on pull-out test results.A database was created combining published experimental data with in-house tests.By means of a comprehensive framework,a Coulomb-type failure criterion accounting for friction mobilization was defined.During the elastic phase,in which the interface joint is not yet created,the proposed model provides zero radial displacement,and once the interface joint is created,interface dilatancy is modeled using a non-associated plastic potential inspired from the behavior of rock joints.The results predicted by the proposed model are in good agreement with experimental results.The model has been implemented in a finite element method(FEM)code and numerical simulations have been performed at the elementary and the structural scales.The results obtained provide confidence in the ability of the new model to assist in the design and optimization of bolting patterns.
文摘In patients suffering from neurogenic detrusor overactivity, continence can be regained by conditional stimulation of the dorsal genital nerve (DGN);that is applying electrical stimulation to the DGN at the onset of an involuntary contraction. For this scheme to work, a sensor capable of reliably detecting the onset of bladder contractions is needed. This article reviews the methods proposed for or associated with detection of bladder contractions, and their applicability to onset detection is assessed. Fourteen methods are described in this review;bladder pressure, urethral sphincter EMG and anal sphincter EMG are the most promising options for onset detection. For all three modalities, however, further research is needed before clinical application becomes viable.
基金This work was supported by the China National Petroleum Corporation.
文摘This note establishes a new method that can measure interface dilatation elastic module (ε) and dilatation viscosity (ηd) of all surfactants based on the surface pressure relaxation process. The wide applicability was proved with the stability of foam as an example.
基金This work was supported by the China National Petroleum Corporation and the Climbing Project of Northern Jiaotong University (Grant Nos. NJTUPD169 and NJTUPD170).
文摘Oil-water interface layers dilatation rheological properties have been measured with the liquid-liquid interface film pressure measurement apparatus, which was based on the principles of Langmuir film balance. Experimental results show that it is possible to form the interface-associated material caused by the attraction of the dispersion forces at the pure alkane-water interface. The type of material is sensitive to the interfacial pressure. Under the influence of the interfacial pressure, the stability of the interface associated materials decreases with the increase of the number of alkane carbons.
文摘Since its discovery, myosin-binding protein C (cMyBP-C) has become a protein of interest clinically. With emergence of new methodologies and technologies, the structure and functions of cMyBP-C from different aspects can be studied, enabling us to better understand its involvement in certain cardiac conditions. Studying its kinetics of release and clearance from the circulation and by comparing to other conventional biomarkers, it has been reported that cMyBP-C is eligible to be a novel biomarker for several cardiac conditions. Moreover, studying the genetics and their involvement in pathogenic mechanisms has opened the ideas for potential therapeutic strategies. More and more researches are constantly being done to better understand the role of cMyBP-C in dilated cardiomyopathy (DCM). The importance of cMyBP-C to the heart is still actively being investigated. Its presence is however crucial for sarcomere organization and proper regulation of cardiac contraction during systole and complete relaxation during diastole. Genetic mutation in cMyBP-C has been linked to cardiac conditions including hypertrophic and dilated cardiomyopathies. Around 350 types of mutations have already been documented leading to various cardiac conditions and abnormalities. Analyzing human heart samples has enabled us to better understand the importance of cMyBP-C and how its mutations lead to inherited cardiomyopathies. It is therefore necessary to have an update about the research progress of cMyBP-C in relation to DCM and other cardiac conditions.
文摘A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h ratios.The model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 e13.5.It was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the rock.The resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression results.Eventually,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test results.The study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.
