Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep wells.This paper aims to predict the casing burst strength with considerations of both wear and corrosion...Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep wells.This paper aims to predict the casing burst strength with considerations of both wear and corrosion.Firstly,the crescent wear shape is simplified into three categories according to common mathematical models.Then,based on the mechano-electrochemical(M-E)interaction,the prediction model of corrosion depth is built with worn depth as the initial condition,and the prediction models of burst strength of the worn casing and corroded casing are obtained.Secondly,the accuracy of different prediction models is validated by numerical simulation,and the main influence factors on casing strength are obtained.At last,the theoretical models are applied to an ultra-deep well in Northwest China,and the dangerous well sections caused by wear and corrosion are predicted,and the corrosion rate threshold to ensure the safety of casing is obtained.The results show that the existence of wear defects results in a stress concentration and enhanced M-E interaction on corrosion depth growth.The accuracy of different mathematical models is different:the slot ring model is most accurate for predicting corrosion depth,and the eccentric model is most accurate for predicting the burst strength of corroded casing.The burst strength of the casing will be overestimated by more than one-third if the M-E interaction is neglected,so the coupling effect of wear and corrosion should be sufficiently considered in casing integrity evaluation.展开更多
A corrosion defect is recognized as one of the most severe phenomena for high-pressure pipelines,especially those served for a long time.Finite-element method and empirical formulas are thereby used for the strength p...A corrosion defect is recognized as one of the most severe phenomena for high-pressure pipelines,especially those served for a long time.Finite-element method and empirical formulas are thereby used for the strength prediction of such pipes with corrosion.However,it is time-consuming for finite-element method and there is a limited application range by using empirical formulas.In order to improve the prediction of strength,this paper investigates the burst pressure of line pipelines with a single corrosion defect subjected to internal pressure based on data-driven methods.Three supervised ML(machine learning)algorithms,including the ANN(artificial neural network),the SVM(support vector machine)and the LR(linear regression),are deployed to train models based on experimental data.Data analysis is first conducted to determine proper pipe features for training.Hyperparameter tuning to control the learning process is then performed to fit the best strength models for corroded pipelines.Among all the proposed data-driven models,the ANN model with three neural layers has the highest training accuracy,but also presents the largest variance.The SVM model provides both high training accuracy and high validation accuracy.The LR model has the best performance in terms of generalization ability.These models can be served as surrogate models by transfer learning with new coming data in future research,facilitating a sustainable and intelligent decision-making of corroded pipelines.展开更多
Objective To explore the feasibility and efficiency of a novel magnetic compression anastomats(MCAs) in intestinal anastomosis.Methods A total of 36 male mongrel canines underwent intestinal anastomosis using traditio...Objective To explore the feasibility and efficiency of a novel magnetic compression anastomats(MCAs) in intestinal anastomosis.Methods A total of 36 male mongrel canines underwent intestinal anastomosis using traditional hand-sewn(n=18) or a novel MCAs(n=18).We compared the anastomosis time,postoperative complications,bursting strength of anastomoses,gross appearance,and pathology between two groups at each time-point of follow-up.Results The mean anastomosis time with MCAs was significantly less than that with hand-sewn(8.50±1.95 vs.31.1±4.32 minutes,P<0.001).The blood stools and intussusceptions occurred in both groups during follow-up period.Only 1 mongrel canine receiving intestinal anastomosis by MCAs experienced anastomotic leakage.The average bursting pressure of anastomoses obtained from mongrel canines undergoing intestinal anastomosis by MCAs was significantly higher than that by traditional hand-sewn at 1 week's follow-up time(P<0.05).Gross appearance of the anastomoses constructed by MCAs was relatively smoother and flatter.Pathological evalution of anastomoses revealed that general inflammation was greater in hand-sewn anastomoses than magnetic anastomosis.Conclusion The magnetic compression anastomat is a safe and effective device of sutureless intestinal anastomosis in canine models.展开更多
Occurrence of vascular diseases is increasing and leads to rising demand for the STENT-GRAFT( SG). To ensure the SG function properly,the materials should have low blood permeability and good mechanical properties. So...Occurrence of vascular diseases is increasing and leads to rising demand for the STENT-GRAFT( SG). To ensure the SG function properly,the materials should have low blood permeability and good mechanical properties. So far, there have been few systematic studies on the relationship between textile structures and mechanical properties of the bio-textiles used in the SG. In this study, six types of biomedical PET fabrics with different yarn structures and fabric structures were designed and fabricated. All the SG materials could meet the requirement of thickness,except the sample of 30 d × 20 d with 2 /2 twill construction,which was thicker than 0. 12 mm. Bursting strength and water permeability( WP) of the six samples were also tested. Through the comparison of comprehensive performance,the PET fabric 30 d × 20 d /12 f with2 /2 twill construction with both good resistances to permeability and bursting strength, might have good prospect in applications of vascular engineering.展开更多
Because of wearing and washing the knit rib fabrics are highly vulnerable to lose their dimensional stability.The work investigated the physical properties of 1×1 knit rib fabrics with or without elastane.The fab...Because of wearing and washing the knit rib fabrics are highly vulnerable to lose their dimensional stability.The work investigated the physical properties of 1×1 knit rib fabrics with or without elastane.The fabrics made from 100%cotton yarn were compared with the fabrics made from cotton/elastane(95%/5%)blended yarns by Lisky circular knitting machine.Pilling,shrinkage,spirality,and bursting strength were tested by the ICI pilling test box,Wascator,and TruBurst machine to demonstrate the effect of elastane on fabric properties.Experimental results showed that elastane has a noteworthy impact on the physical properties of 1×1 knit rib fabrics which can make the fabrics more durable and dimensionally stable in practice.展开更多
The physical and dimensional characteristics, i.e. course and wale spacing, stitch density, tightness factor, diameter, porosity, dimensional stability and bursting strength of single jersey knitted items containing l...The physical and dimensional characteristics, i.e. course and wale spacing, stitch density, tightness factor, diameter, porosity, dimensional stability and bursting strength of single jersey knitted items containing lycra yarn with the variations in stitch length and lycra content have been examined and a detail investigation on the lycra filament has been discussed in this study. Six different samples were knitted with identical cotton and lycra yarn but different in lycra contents and stitch length. After conditioning in a controlled environment, all the samples were tested as per the established methods. After analyzing the test results, noticeable effects of variations in stitch length and lycra content on physical and dimensional characteristics of single jersey knitted fabric has been found. As smaller the stitch length and as greater the lycra content, the dimensional stability and bursting strength are better;on the other hand, the air permeability is lower.展开更多
Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showe...Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.展开更多
文摘Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep wells.This paper aims to predict the casing burst strength with considerations of both wear and corrosion.Firstly,the crescent wear shape is simplified into three categories according to common mathematical models.Then,based on the mechano-electrochemical(M-E)interaction,the prediction model of corrosion depth is built with worn depth as the initial condition,and the prediction models of burst strength of the worn casing and corroded casing are obtained.Secondly,the accuracy of different prediction models is validated by numerical simulation,and the main influence factors on casing strength are obtained.At last,the theoretical models are applied to an ultra-deep well in Northwest China,and the dangerous well sections caused by wear and corrosion are predicted,and the corrosion rate threshold to ensure the safety of casing is obtained.The results show that the existence of wear defects results in a stress concentration and enhanced M-E interaction on corrosion depth growth.The accuracy of different mathematical models is different:the slot ring model is most accurate for predicting corrosion depth,and the eccentric model is most accurate for predicting the burst strength of corroded casing.The burst strength of the casing will be overestimated by more than one-third if the M-E interaction is neglected,so the coupling effect of wear and corrosion should be sufficiently considered in casing integrity evaluation.
文摘A corrosion defect is recognized as one of the most severe phenomena for high-pressure pipelines,especially those served for a long time.Finite-element method and empirical formulas are thereby used for the strength prediction of such pipes with corrosion.However,it is time-consuming for finite-element method and there is a limited application range by using empirical formulas.In order to improve the prediction of strength,this paper investigates the burst pressure of line pipelines with a single corrosion defect subjected to internal pressure based on data-driven methods.Three supervised ML(machine learning)algorithms,including the ANN(artificial neural network),the SVM(support vector machine)and the LR(linear regression),are deployed to train models based on experimental data.Data analysis is first conducted to determine proper pipe features for training.Hyperparameter tuning to control the learning process is then performed to fit the best strength models for corroded pipelines.Among all the proposed data-driven models,the ANN model with three neural layers has the highest training accuracy,but also presents the largest variance.The SVM model provides both high training accuracy and high validation accuracy.The LR model has the best performance in terms of generalization ability.These models can be served as surrogate models by transfer learning with new coming data in future research,facilitating a sustainable and intelligent decision-making of corroded pipelines.
基金Support by the National Natural Science Foundation of China (30830099)
文摘Objective To explore the feasibility and efficiency of a novel magnetic compression anastomats(MCAs) in intestinal anastomosis.Methods A total of 36 male mongrel canines underwent intestinal anastomosis using traditional hand-sewn(n=18) or a novel MCAs(n=18).We compared the anastomosis time,postoperative complications,bursting strength of anastomoses,gross appearance,and pathology between two groups at each time-point of follow-up.Results The mean anastomosis time with MCAs was significantly less than that with hand-sewn(8.50±1.95 vs.31.1±4.32 minutes,P<0.001).The blood stools and intussusceptions occurred in both groups during follow-up period.Only 1 mongrel canine receiving intestinal anastomosis by MCAs experienced anastomotic leakage.The average bursting pressure of anastomoses obtained from mongrel canines undergoing intestinal anastomosis by MCAs was significantly higher than that by traditional hand-sewn at 1 week's follow-up time(P<0.05).Gross appearance of the anastomoses constructed by MCAs was relatively smoother and flatter.Pathological evalution of anastomoses revealed that general inflammation was greater in hand-sewn anastomoses than magnetic anastomosis.Conclusion The magnetic compression anastomat is a safe and effective device of sutureless intestinal anastomosis in canine models.
基金the Key Project of the National Nature Science Foundation of China(No.61134009)Program for Changjiang Scholars and Innovation Research Team in University from the Ministry of Education,China(No.IRT1220)+1 种基金Specialized Research Funds for Shanghai Leading Talents,Project of the Shanghai Committee of Science and Technology,China,(No.13JC1407500)the Fundamental Research Funds for the Central Universities,China(No.2232012A3-04)
文摘Occurrence of vascular diseases is increasing and leads to rising demand for the STENT-GRAFT( SG). To ensure the SG function properly,the materials should have low blood permeability and good mechanical properties. So far, there have been few systematic studies on the relationship between textile structures and mechanical properties of the bio-textiles used in the SG. In this study, six types of biomedical PET fabrics with different yarn structures and fabric structures were designed and fabricated. All the SG materials could meet the requirement of thickness,except the sample of 30 d × 20 d with 2 /2 twill construction,which was thicker than 0. 12 mm. Bursting strength and water permeability( WP) of the six samples were also tested. Through the comparison of comprehensive performance,the PET fabric 30 d × 20 d /12 f with2 /2 twill construction with both good resistances to permeability and bursting strength, might have good prospect in applications of vascular engineering.
文摘Because of wearing and washing the knit rib fabrics are highly vulnerable to lose their dimensional stability.The work investigated the physical properties of 1×1 knit rib fabrics with or without elastane.The fabrics made from 100%cotton yarn were compared with the fabrics made from cotton/elastane(95%/5%)blended yarns by Lisky circular knitting machine.Pilling,shrinkage,spirality,and bursting strength were tested by the ICI pilling test box,Wascator,and TruBurst machine to demonstrate the effect of elastane on fabric properties.Experimental results showed that elastane has a noteworthy impact on the physical properties of 1×1 knit rib fabrics which can make the fabrics more durable and dimensionally stable in practice.
文摘The physical and dimensional characteristics, i.e. course and wale spacing, stitch density, tightness factor, diameter, porosity, dimensional stability and bursting strength of single jersey knitted items containing lycra yarn with the variations in stitch length and lycra content have been examined and a detail investigation on the lycra filament has been discussed in this study. Six different samples were knitted with identical cotton and lycra yarn but different in lycra contents and stitch length. After conditioning in a controlled environment, all the samples were tested as per the established methods. After analyzing the test results, noticeable effects of variations in stitch length and lycra content on physical and dimensional characteristics of single jersey knitted fabric has been found. As smaller the stitch length and as greater the lycra content, the dimensional stability and bursting strength are better;on the other hand, the air permeability is lower.
基金sponsored by Coal and Energy Research Bureau and CDC-NIOSH under Grant No.R01OH009532
文摘Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.
