Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
BACKGROUND A case study of multiple distinct levels of skipped thoracolumbar spine infection was reported in which 13 successful vacuum sealing drainage(VSD)surgeries were treated.CASE SUMMARY The patient underwent a ...BACKGROUND A case study of multiple distinct levels of skipped thoracolumbar spine infection was reported in which 13 successful vacuum sealing drainage(VSD)surgeries were treated.CASE SUMMARY The patient underwent a total of 13 procedures within our medical facility,including five performed under local anesthesia and eight performed under general anesthesia.The source of the ailment was ultimately identified as Enterobacter cloacae.After the last procedure,the patient's symptoms were alleviated,and the recovery process was satisfactory.Three months post-operation,the Japanese Orthopaedic Association scores had improved to 100%.Imageological examination revealed a satisfactory position of internal fixation,and the abnormal signals in the vertebral body and intervertebral space had been eliminated when compared to the pre-operative results.CONCLUSION The study demonstrates that the extreme lateral approach debridement combined with multiple VSD operations is a secure and successful method of treatment for recurrent spinal infection,providing an alternative to traditional surgery.展开更多
A ternary early-strengthening agent consisting of calcium formate+triethanolamine+lithium sulfate was compounded with quercetin to shorten the setting time of cementitious materials while ensuring their early strength...A ternary early-strengthening agent consisting of calcium formate+triethanolamine+lithium sulfate was compounded with quercetin to shorten the setting time of cementitious materials while ensuring their early strength.The optimum ratio of the three early-strengthening agents was determined as 0.5%calcium formate+0.04%triethanolamine+0.4%lithium sulfate by response surface methodology.The effects of the ternary early-strengthening agent composed of calcium formate+triethanolamine(TEA)+lithium sulfate on cementitious pore sealing materials under the synergistic effect of quercetin were studied by means of the performance tests of compressive strength,fluidity,and setting time,and the microstructural characterizations of X-ray powder diffractometer(XRD),thermogravimetry(TG-DSC)and scanning electron microscopy(SEM).The study shows that the synergistic effect of ternary early-strengthening agent and quercetin forms a multi-performance composite admixture for cementitious materials.The best performance was obtained with the compounding scheme of 0.5%calcium formate+0.04%triethanolamine+0.4%lithium sulfate ternary early-strengthening agent and 0.05%quercetin.The compressive strength of 1,3,7,and 28 d are 94.8%,39.8%,42%,and 28%higher than those of the blank group,respectively.The initial time and final setting time are 41 and 57 minutes,respectively.According to the microscopic analysis,the network and fibrous C-S-H gels generated by ternary early-strengthening agents are attached to the surface promoted by quercetin,which forms skeleton support while thickening and solidifying the cement slurry,which enhances the early compressive strength of the cement-based materials.展开更多
The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with B...The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with Bi/Si ratio in low-melting glass was investigated.In addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were revealed.The results show that a decrease in the Bi/Si ratio can cause a contraction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its coefficient of thermal expansion.During laser sealing,the copper ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the copper ions in the low-melting glass.The absorbance of the low-melting glass does not follow the expected correlation with the Bi/Si ratio,but shows a linear correlation with the content of divalent copper ions.The greater the concentration of divalent copper ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser sealing.The shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.展开更多
In the process of oil and gas production,reservoir pressure depletion leads to changes in pore pressure and in-situ stress in caprock,which may reactivate closed faults in caprock,break the sealing of caprock,and make...In the process of oil and gas production,reservoir pressure depletion leads to changes in pore pressure and in-situ stress in caprock,which may reactivate closed faults in caprock,break the sealing of caprock,and make depleted oil and gas reservoirs unsuitable for gas storage.In order to effectively evaluate the sealing of faults in caprock above depleted reservoir and provide a basis for a reasonable selection of injection time and location for gas storage,this paper comprehensively considers fault slip potential(FSP)and fault tensile potential(FTP),and establishes a fault sealing evaluation model in caprock above depleted reservoir.The influences of distance of fault from reservoir top,reservoir pressure depletion degree,cap mechanical property,fault occurrence,fault frictional property and in-situ stress anisotropy in caprock on different types of FSP and FTP are analyzed.The results show that for normal faults,reverse faults,and strike-slip faults,FTP increases with reservoir depletion and does not cause tensile failure,among which FTP is the smallest for normal faults.FSP is the key to controlling fault sealing in caprock above depleted reservoir.For reverse faults and strike-slip faults,in the early stage of reservoir depletion,the FsP is larger when the fault is farther away from the top of the reservoir,while normal faults are the opposite.When the normal fault is closer to the top of the reservoir,the cap poisson ratio is smaller,the Biot's coefficient is larger,the internal friction coefficient of the fault is smaller,the inherent shear strength of the fault is smaller,σH/σv is smaller,σh/σv is smaller,45°<β<75°,α=0° or α=180°,the FSP is larger with the reservoir depletion,and the shear failure of the fault is the most likely.At this time,the reservoir pressure should be strictly controlled not to be too small,so that it can be suitable for the construction of gas storage.Under other conditions,the possibility of shear failure of the caprock is less.For reverse faults and strike-slip faults,when is smaller,the FSP decreases first and then increases with reservoir depletion.Although the possibility of shear failure decreases in the initial stage of reservoir depletion,it increases in the later stage.The research results can provide a theoretical basis for the reconstruction of underground gas storage.展开更多
BACKGROUND The current method of cleaning and changing dressings for non-healing lumbar incisions post-radiotherapy is time-consuming and laborious,with very poor results.We here report a patient with radiation dermat...BACKGROUND The current method of cleaning and changing dressings for non-healing lumbar incisions post-radiotherapy is time-consuming and laborious,with very poor results.We here report a patient with radiation dermatitis who developed a nonhealing wound after lumbar spinal surgery.The wound was successfully treated with vacuum sealing drainage therapy,confirming its feasibility in complex wound healing.CASE SUMMARY The patient was a 76-year-old female with lung cancer,positron emission tomography/computed tomography showed bone metastasis in L2 and L3 vertebrae.After 2 months of local radiotherapy to the lumbar spine,symptoms did not improve and pain worsened.She had lumbar lesion clearance and internal fixation surgery,but developed a nonhealing wound of approximately 15 cm postoperatively.After 12 rounds of clearing necrotic and unhealthy tissue,78 days of negative pressure therapy promoted granulation tissue growth and wound healing,resulting in wound healing.CONCLUSION Vacuum sealing drainage therapy has shown efficacy in treating nonhealing wounds after radiotherapy,promoting wound healing and reducing infection risk.展开更多
Pipeline Inspection Gauge(pig)is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering,cleaning,and inspection.Owing to the hyperelasticit...Pipeline Inspection Gauge(pig)is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering,cleaning,and inspection.Owing to the hyperelasticity,time and temperature-dependent material behaviour of the sealing disc attached on the pig,the contact between the pig and the pipeline expresses complex behaviour,leading to an uncertainty in the prediction of the pig's frictional force.Knowing the deformation of the sealing discs well is essential and can be highly meaningful for predicting the pig motion,as well as reducing the pigging risks.In this study,the geometrical deformation of the sealing discs with different sizes are investigated through experiments and numerical simulations.The effects of the four nondimensionalized parameters(interference,thickness per pipeline inner diameter,and clamping ratio)of the sealing discs on the deformation behaviour were observed and discussed,and an improved mathematical model for predicting the geometrical deformation of the sealing discs was proposed and verified.With the auxiliary angleαadded in the improved mathematical model,the relative error declines to 1.87%and 3.18%respectively for predicting deformation of the sealing discs in size of 2-inch and 40-inch pig.The results of this study can help better understand the frictional force of a pig with sealing discs,as well as its motion.展开更多
The cyclic injection and production of fluids into and from underground gas storage(UGS)may lead to caprock failure,such as capillary sealing failure,hydraulic fracturing,shear failure,and fault slipping or dilation.T...The cyclic injection and production of fluids into and from underground gas storage(UGS)may lead to caprock failure,such as capillary sealing failure,hydraulic fracturing,shear failure,and fault slipping or dilation.The dynamic sealing capacity of a caprock-fault system is a critical constraint for safe operation,and is a key factor in determining the maximum operating pressure(MOP).This study proposed an efficient semi-analytical method for calculating changes in the in situ stress within the caprock.Next,the parameters of dynamic pore pressure,in situ stresses,and deformations obtained from reservoir simulations and geomechanical modeling were used for inputs for the analytical solution.Based on the calculated results,an experimental scheme for the coupled cyclic stress-permeability testing of caprock was designed.The stability analysis indicated that the caprock was not prone to fatigue shear failure under the current injection and production strategy,supported by the experimental results.The experimental results further reveal that the sealing capacity of caprock plugs may remain stable.This phenomenon is attributed to cyclic stress causing pore connectivity and microcrack initiation in certain plugs,while leading to pore compaction in others.A comparison between the dynamic pore pressure and the minimum principal stress suggests that the risk of tensile failure is extremely low.Furthermore,although the faults remain stable under the current injection and production strategies,the continuous increase in injection pressure may lead to an increased tendency for fault slip and dilation,which can cause fault slip ultimately.The MOPs corresponding to each failure mode were calculated.The minimum value of approximately 36.5 MPa at capillary sealing failure indicated that the gas breakthrough in the caprock occurred earlier than rock failure.Therefore,this minimumvalue can be used as the MOP for the target UGS.展开更多
Fluid channeling caused by seal failure at the cement sheath-formation interface during fracturing is a severe problem in oil gas wells.In this study,a novel model was developed to evaluate interface sealing integrity...Fluid channeling caused by seal failure at the cement sheath-formation interface during fracturing is a severe problem in oil gas wells.In this study,a novel model was developed to evaluate interface sealing integrity.The model's accuracy was verified based on a self-developed interface seal evaluation device and an experiment.Subsequently,the interface seal under different formation conditions was investigated using this model.The theoretical calculation showed that for a cement sheath-carbonate formation interface,the channeling of acid-fracturing fluid caused interface seal failure and sustained casing pressure in the annulus space between the technical casing and formation.Mutual channeling between the fracturing sections occurred at the cement sheathshale formation interface during fracturing.For a sandstone formation,the interface seal failure caused the channeling between a water-bearing formation and a sandstone formation.Aiming at different formation conditions,the mechanical properties requirements of Young's modulus and Poisson's ratio of cement sheath were proposed respectively to ensure its seal integrity.The proposed model and method can be used to evaluate and optimize sealing integrity during fracturing.展开更多
Hardfacing of valve sealings in power plants with Inconel 625 alloy has been reviewed in this paper.The overlaying processes,over-lay microstructures,and weldability issues during the hardfacing process have been anal...Hardfacing of valve sealings in power plants with Inconel 625 alloy has been reviewed in this paper.The overlaying processes,over-lay microstructures,and weldability issues during the hardfacing process have been analyzed.The results indicate that almost all melting welding processes can be used for hardfacing of Inconel 625 alloy.During hardfacing,it is necessary to strictly control the penetration,reduce the overlay dilution rate,so as to prevent the formation of partially mixed zone(PMZ)and solidification crack.From the perspective of controlling the penetration,reducing the overlay dilution rate,and automated hardfacing,the most suitable process for hardfacing Inconel 625 alloy on the valve sealings in power plants is cold metal transfer(CMT)welding process.展开更多
In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequen...In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequently leading to the failure and damage of threaded connections.In severe cases,it can result in considerable economic losses and trigger safety accidents.The sealing performance of special bolted joints holds crucial importance for production efficiency,output,equipment lifespan,and cost control.Enhancing the sealing perfor-mance of threaded connections can have a positive impact on industrial production and environmental protection.The existing research on American Petroleum Institute threaded joints has been thorough and has obtained a series of excellent results.However,the research on the sealing damage mechanism of threaded connections under complex well conditions lacks sufficient depth and that on new sealing technology is scarce.This study proposes a half-size evaluation test to address the abovementioned problem.Based on this test,an investigation into the sealing performance of threaded connections under high-temperature,cyclic loading,and high-temperature creep conditions is conducted.This study uses a combined approach of finite element methods and experiments to investigate the impact of different makeup torques on the sealing performance of premium threaded connections(PTCs).The results of the half-size evaluation test indicate that temperature notably influences the sealing performance of threaded connections.The continuous action of high temperatures causes contact pressure and sealing performance to decrease,and sealing contact pressure increases after cooling.Finite element and test results show that for a certain joint A,the greater the torque,the higher the critical sealing pressure of the thread,and the better the sealing performance.The research on the sealing damage mechanism of PTCs provides a scientific basis and theoretical guidance for the further optimization and development of PTCs.展开更多
Manufacturers must identify and classify various defects in automotive sealing rings to ensure product quality.Deep learning algorithms show promise in this field,but challenges remain,especially in detecting small-sc...Manufacturers must identify and classify various defects in automotive sealing rings to ensure product quality.Deep learning algorithms show promise in this field,but challenges remain,especially in detecting small-scale defects under harsh industrial conditions with multimodal data.This paper proposes an enhanced version of You Only Look Once(YOLO)v8 for improved defect detection in automotive sealing rings.We introduce the Multi-scale Adaptive Feature Extraction(MAFE)module,which integrates Deformable ConvolutionalNetwork(DCN)and Spaceto-Depth(SPD)operations.This module effectively captures long-range dependencies,enhances spatial aggregation,and minimizes information loss of small objects during feature extraction.Furthermore,we introduce the Blur-Aware Wasserstein Distance(BAWD)loss function,which improves regression accuracy and detection capabilities for small object anchor boxes,particularly in scenarios involving defocus blur.Additionally,we have constructed a high-quality dataset of automotive sealing ring defects,providing a valuable resource for evaluating defect detection methods.Experimental results demonstrate our method’s high performance,achieving 98.30% precision,96.62% recall,and an inference speed of 20.3 ms.展开更多
Dear Editor,We report a surgical method for treating repeat Descemet’s membrane(DM)detachments in two cases with DM micro-perforation during deep anterior lamellar keratoplasty(DALK).DM micro-perforation is a common ...Dear Editor,We report a surgical method for treating repeat Descemet’s membrane(DM)detachments in two cases with DM micro-perforation during deep anterior lamellar keratoplasty(DALK).DM micro-perforation is a common intraoperative complication that occurs during the performance of DM baring in DALK,using methods such as the bigbubble air technique[1].The sequelae of DM micro-perforations include postoperative DM detachments,higher endothelial cell loss,endothelial decompensation,and transplant interface scarring[2].展开更多
A rotary sealing device that automatically compensates for wear is designed to address the issues of easy wear and the short service life of the rotary sealing device with automatic wear compensation in mining machine...A rotary sealing device that automatically compensates for wear is designed to address the issues of easy wear and the short service life of the rotary sealing device with automatic wear compensation in mining machinery.After the end face of the guide sleeve wears out,it still tightly adheres to the sealing valve seat under the pressure difference,achieving automatic wear compensation.Based on fluid-solid coupling technology,the structural strength of the rotary sealing device was checked.The influence of factors on the sealing performance of rotary sealing devices was studied using the control variable method.The results show that as the pressure of water increases,the leakage rate of the sealing device decreases,and after 30 MPa,the leakage rate is almost 0 mL/h.The temperature of the rotating sealing device increases with the increase of rotation speed or pressure,and the temperature is more affected by the rotation speed factor.The frictional torque increases with increasing pressure and is independent of rotational speed.Comprehensive analysis shows that the wear resistance and reliability level of the sealing guide sleeve material is PVDF>PEEK>PE>PA.This study designs a high-pressure automatic compensation wear rotary sealing device and selects the optimal sealing material,providing technical support for the application of high-pressure water jet in mining machinery.展开更多
The metal sealing performance of subsea X-tree wellhead connectors is crucial for the safety and reliability of subsea X-trees. In order to establish the theoretical relation between metal sealing ring＇s contact stre...The metal sealing performance of subsea X-tree wellhead connectors is crucial for the safety and reliability of subsea X-trees. In order to establish the theoretical relation between metal sealing ring＇s contact stress and its structural parameters and working pressure, a mechanical analysis method for double-cone sealing of high pressure vessels is applied in analyzing the metal sealing ring under the condition of preload and operation. As a result, the formula of the unit sealing load for the metal sealing ring under operation with residual preload is shown in this paper, which ensures that the metal sealing ring has an excellent sealing effect and can prevent the metal sealing ring from yielding. Besides, while analyzing the sealing process of the metal sealing ring, the change rule of contact stress and working pressure is concluded here, putting forward that the structural parameters of the metal sealing ring are the major factors affecting the change rule. Finally, the analytical solution through theoretical analysis is compared with the simulation result through finite element analysis in a force feedback experiment, and both are consistent with each other, which fully verifies for the design and calculation theory on metal sealing ring＇s contact stress and its structural parameters and working pressure deduced in this paper. The proposed research will be treated as an applicable theory guiding the design of metal seal for subsea X-tree wellhead connectors.展开更多
In order to speed underwater launch of minor-caliber weapons,a sealing device can be set in front of underwater muzzle to separate water,preventing the muzzle from water immersion.By establishing and simplifying the m...In order to speed underwater launch of minor-caliber weapons,a sealing device can be set in front of underwater muzzle to separate water,preventing the muzzle from water immersion.By establishing and simplifying the model of underwater weapon sealing device and unstructured mesh computing domain model based on computational fluid dynamics（CFD）,dynamic mesh and user defined function（UDF）,the N-S equation is solved and the numerical analysis and calculation of the complex two-phase flow inside the sealing device are carried out.The results show that the gas discharged from the sealing device is conducive to the formation of the projectile supercavity.When the projectile is launched at 5munder water,the shock wave before and after the projectile has impact on the box body up to 100 MPa,therefore the sealing device must be strong enough.The research results have the vital significance to the design of underwater weapon sealing device and the formation of the projectile supercavitation.展开更多
Researchers seldom study the optimum design of a mechanical connector for subsea oil-gas pipeline based upon the sealing performance. An optimal design method of a novel subsea pipeline mechanical connector is present...Researchers seldom study the optimum design of a mechanical connector for subsea oil-gas pipeline based upon the sealing performance. An optimal design method of a novel subsea pipeline mechanical connector is presented. By analyzing the static metal sealing mechanism, the critical condition of the sealing performance is established for this connector and the formulation method of the contact pressure on the sealing surface is created. By the method the minimum mean contact pressure of the 8.625 inch connector is calculated as 361 MPa, which is the constraint condition in the optimum design of connector.The finite element model is created in ANSYS Parametric Design Language(APDL) and the structure is optimized by the zero-order method, with variance of contact pressure as the objective function, and mean contact pressures and plastic strains as constraint variables. The optimization shows that variances of contact pressure on two sealing surfaces decrease by 72.41% and 89.33%, respectively, and mean contact pressures increase by 31.18% and 52.84%, respectively. The comparison of the optimal connectors and non-optimal connectors in the water pressure experiments and bending experiments shows that the sealing ability of optimized connectors is much higher than the rated pressure of 4.5 MPa, and the optimal connectors don’t leak under the bending moment of 52.2 kN·m.This research provides the formulation to solve contact pressure on the sealing surface and a structure optimization method to design the connectors with various dimensions.展开更多
Lost circulations have presented great challenges to the petroleum industry, causing great expenditures of cash and time to fighting the problem. Probably the most problematic situations are the naturally fractured fo...Lost circulations have presented great challenges to the petroleum industry, causing great expenditures of cash and time to fighting the problem. Probably the most problematic situations are the naturally fractured formations where the operator may face total loss with no mud return in the annular. The voids or large fracture encountered in this case are often far too large to be plugged with conventional Lost Circulation Material. This paper will give a detailed introduction on a novel composite gel material usable to control severe losses and pressurization sealing. The plugging mechanics of this new composite gel material, which is different from conventional lost circulation materials, were elaborated as well. In addition, the properties of the new composite gel material such as thermostability, sealing strength and bearing resistance are characterized with specific experimental devices. The experimental results proved that the breakdown pressure of the new plugging reached more than 20MPa, and the maximum degraded temperature can be exceed 130℃. The field application at 4 wells in Puguang gas field, SINOPEC, demonstrated that the new composite gel material solved the serious loss in Ordovician carbonate fractured formation successfully and guaranteed the following completion cement operation smoothly. The composite gel sealing slurries, which was easily prepared on site, gives remarkable properties regarding pumping through drill pipes, adjustment of setting time and excellent sealing strength of the lost zone sealing, additionally, the whole pressurization sealing process was complicated within only ten hours. The on-site results show that the plugging ratio of the new composite gel was reached 100%, and the success rate of sealing operation kept above 80%.Thus the new LCM can guarantee safe drilling jobs and save operation cost more effectively.展开更多
It is of great significance to study the controlling effect of sealing systems on CBM enrichment in coalbed methane (CBM) exploration anddevelopment. In this paper, the relationships between CBM enrichment and geologi...It is of great significance to study the controlling effect of sealing systems on CBM enrichment in coalbed methane (CBM) exploration anddevelopment. In this paper, the relationships between CBM enrichment and geological elements were analyzed. The geological elements includesealing layers (e.g. regional cap rock, regional floor, and immediate roof and floor), later structural adjustment and strata production status. It isshown that CBM tends to enrich in the areas where regional mudstone cap rocks and floors are distributed stably, structures are uplifted andinversed slightly after the hydrocarbon accumulation period and the strata is gentle in a balanced state. Then, the concept of sealing system wasput forward based on the worldwide CBM exploration and development practices over the years. A sealing system refers to a geological unitcomposed of a lateral stable zone and cap rock which prevents gas from migrating upward and downward. In a sealing system, CBM can getenriched and coal-measure gas can also be accumulated. Finally, three gas reservoir types (i.e., sandwich-type CBM reservoir, associated CBM-sandstone gas reservoir and coal-derived sandstone gas reservoir) were identified based on the configuration relationships between elements ofthe CBM (or coal-measure gas) sealing system. It is recommended to change the exploration ideas from simple CBM exploration to 3D CBMand coal-measure gas exploration. In addition, an evaluation index system of CBM (or coal-measure gas) geological selection was established. Itis pointed out that good application effects may be realized if the stereoscopic CBM and coal-measure gas exploration is applied in the JunggarBasin and the eastern margin of the Ordos Basin.展开更多
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
基金Supported by Natural Science Foundation of Shandong Province,No.ZR2023MH331.
文摘BACKGROUND A case study of multiple distinct levels of skipped thoracolumbar spine infection was reported in which 13 successful vacuum sealing drainage(VSD)surgeries were treated.CASE SUMMARY The patient underwent a total of 13 procedures within our medical facility,including five performed under local anesthesia and eight performed under general anesthesia.The source of the ailment was ultimately identified as Enterobacter cloacae.After the last procedure,the patient's symptoms were alleviated,and the recovery process was satisfactory.Three months post-operation,the Japanese Orthopaedic Association scores had improved to 100%.Imageological examination revealed a satisfactory position of internal fixation,and the abnormal signals in the vertebral body and intervertebral space had been eliminated when compared to the pre-operative results.CONCLUSION The study demonstrates that the extreme lateral approach debridement combined with multiple VSD operations is a secure and successful method of treatment for recurrent spinal infection,providing an alternative to traditional surgery.
基金Funded by the Key Technologies Research and Development Program(No.2021YFC28000900)the National Natural Science Foundation of China(No.52374178)the Collaborative Innovation Project of Colleges and Universities of Anhui Province(No.GXXT-2020-057)。
文摘A ternary early-strengthening agent consisting of calcium formate+triethanolamine+lithium sulfate was compounded with quercetin to shorten the setting time of cementitious materials while ensuring their early strength.The optimum ratio of the three early-strengthening agents was determined as 0.5%calcium formate+0.04%triethanolamine+0.4%lithium sulfate by response surface methodology.The effects of the ternary early-strengthening agent composed of calcium formate+triethanolamine(TEA)+lithium sulfate on cementitious pore sealing materials under the synergistic effect of quercetin were studied by means of the performance tests of compressive strength,fluidity,and setting time,and the microstructural characterizations of X-ray powder diffractometer(XRD),thermogravimetry(TG-DSC)and scanning electron microscopy(SEM).The study shows that the synergistic effect of ternary early-strengthening agent and quercetin forms a multi-performance composite admixture for cementitious materials.The best performance was obtained with the compounding scheme of 0.5%calcium formate+0.04%triethanolamine+0.4%lithium sulfate ternary early-strengthening agent and 0.05%quercetin.The compressive strength of 1,3,7,and 28 d are 94.8%,39.8%,42%,and 28%higher than those of the blank group,respectively.The initial time and final setting time are 41 and 57 minutes,respectively.According to the microscopic analysis,the network and fibrous C-S-H gels generated by ternary early-strengthening agents are attached to the surface promoted by quercetin,which forms skeleton support while thickening and solidifying the cement slurry,which enhances the early compressive strength of the cement-based materials.
基金Funded by the National Natural Science Foundation of China(No.52472012)Opening Project of State Silica-Based Materials Laboratory of Anhui Province(No.2022KF11)the Research and Development of Glass Powder for Laser Sealing and Its Sealing Technology(No.K24556)。
文摘The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with Bi/Si ratio in low-melting glass was investigated.In addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were revealed.The results show that a decrease in the Bi/Si ratio can cause a contraction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its coefficient of thermal expansion.During laser sealing,the copper ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the copper ions in the low-melting glass.The absorbance of the low-melting glass does not follow the expected correlation with the Bi/Si ratio,but shows a linear correlation with the content of divalent copper ions.The greater the concentration of divalent copper ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser sealing.The shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.
基金National Natural Science Foundation of China(52074224)Key Research and Development Program of Shaanxi Province(2023-YBGY-312).
文摘In the process of oil and gas production,reservoir pressure depletion leads to changes in pore pressure and in-situ stress in caprock,which may reactivate closed faults in caprock,break the sealing of caprock,and make depleted oil and gas reservoirs unsuitable for gas storage.In order to effectively evaluate the sealing of faults in caprock above depleted reservoir and provide a basis for a reasonable selection of injection time and location for gas storage,this paper comprehensively considers fault slip potential(FSP)and fault tensile potential(FTP),and establishes a fault sealing evaluation model in caprock above depleted reservoir.The influences of distance of fault from reservoir top,reservoir pressure depletion degree,cap mechanical property,fault occurrence,fault frictional property and in-situ stress anisotropy in caprock on different types of FSP and FTP are analyzed.The results show that for normal faults,reverse faults,and strike-slip faults,FTP increases with reservoir depletion and does not cause tensile failure,among which FTP is the smallest for normal faults.FSP is the key to controlling fault sealing in caprock above depleted reservoir.For reverse faults and strike-slip faults,in the early stage of reservoir depletion,the FsP is larger when the fault is farther away from the top of the reservoir,while normal faults are the opposite.When the normal fault is closer to the top of the reservoir,the cap poisson ratio is smaller,the Biot's coefficient is larger,the internal friction coefficient of the fault is smaller,the inherent shear strength of the fault is smaller,σH/σv is smaller,σh/σv is smaller,45°<β<75°,α=0° or α=180°,the FSP is larger with the reservoir depletion,and the shear failure of the fault is the most likely.At this time,the reservoir pressure should be strictly controlled not to be too small,so that it can be suitable for the construction of gas storage.Under other conditions,the possibility of shear failure of the caprock is less.For reverse faults and strike-slip faults,when is smaller,the FSP decreases first and then increases with reservoir depletion.Although the possibility of shear failure decreases in the initial stage of reservoir depletion,it increases in the later stage.The research results can provide a theoretical basis for the reconstruction of underground gas storage.
文摘BACKGROUND The current method of cleaning and changing dressings for non-healing lumbar incisions post-radiotherapy is time-consuming and laborious,with very poor results.We here report a patient with radiation dermatitis who developed a nonhealing wound after lumbar spinal surgery.The wound was successfully treated with vacuum sealing drainage therapy,confirming its feasibility in complex wound healing.CASE SUMMARY The patient was a 76-year-old female with lung cancer,positron emission tomography/computed tomography showed bone metastasis in L2 and L3 vertebrae.After 2 months of local radiotherapy to the lumbar spine,symptoms did not improve and pain worsened.She had lumbar lesion clearance and internal fixation surgery,but developed a nonhealing wound of approximately 15 cm postoperatively.After 12 rounds of clearing necrotic and unhealthy tissue,78 days of negative pressure therapy promoted granulation tissue growth and wound healing,resulting in wound healing.CONCLUSION Vacuum sealing drainage therapy has shown efficacy in treating nonhealing wounds after radiotherapy,promoting wound healing and reducing infection risk.
基金supported by Key Technologies Research and Development Program(Grant No.SQ2022YFC2806103)and the National Natural Science Foundation of China(Grant No.51509259).
文摘Pipeline Inspection Gauge(pig)is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering,cleaning,and inspection.Owing to the hyperelasticity,time and temperature-dependent material behaviour of the sealing disc attached on the pig,the contact between the pig and the pipeline expresses complex behaviour,leading to an uncertainty in the prediction of the pig's frictional force.Knowing the deformation of the sealing discs well is essential and can be highly meaningful for predicting the pig motion,as well as reducing the pigging risks.In this study,the geometrical deformation of the sealing discs with different sizes are investigated through experiments and numerical simulations.The effects of the four nondimensionalized parameters(interference,thickness per pipeline inner diameter,and clamping ratio)of the sealing discs on the deformation behaviour were observed and discussed,and an improved mathematical model for predicting the geometrical deformation of the sealing discs was proposed and verified.With the auxiliary angleαadded in the improved mathematical model,the relative error declines to 1.87%and 3.18%respectively for predicting deformation of the sealing discs in size of 2-inch and 40-inch pig.The results of this study can help better understand the frictional force of a pig with sealing discs,as well as its motion.
基金supported by the National Natural Science Foundation of China(Grant No.42072166)Natural Science Foundation of Heilongjiang Province of China(Grant No.LH2020D004)Key R&D Program of Heilongjiang Province of China(Grant No.JD2023SJ26)。
文摘The cyclic injection and production of fluids into and from underground gas storage(UGS)may lead to caprock failure,such as capillary sealing failure,hydraulic fracturing,shear failure,and fault slipping or dilation.The dynamic sealing capacity of a caprock-fault system is a critical constraint for safe operation,and is a key factor in determining the maximum operating pressure(MOP).This study proposed an efficient semi-analytical method for calculating changes in the in situ stress within the caprock.Next,the parameters of dynamic pore pressure,in situ stresses,and deformations obtained from reservoir simulations and geomechanical modeling were used for inputs for the analytical solution.Based on the calculated results,an experimental scheme for the coupled cyclic stress-permeability testing of caprock was designed.The stability analysis indicated that the caprock was not prone to fatigue shear failure under the current injection and production strategy,supported by the experimental results.The experimental results further reveal that the sealing capacity of caprock plugs may remain stable.This phenomenon is attributed to cyclic stress causing pore connectivity and microcrack initiation in certain plugs,while leading to pore compaction in others.A comparison between the dynamic pore pressure and the minimum principal stress suggests that the risk of tensile failure is extremely low.Furthermore,although the faults remain stable under the current injection and production strategies,the continuous increase in injection pressure may lead to an increased tendency for fault slip and dilation,which can cause fault slip ultimately.The MOPs corresponding to each failure mode were calculated.The minimum value of approximately 36.5 MPa at capillary sealing failure indicated that the gas breakthrough in the caprock occurred earlier than rock failure.Therefore,this minimumvalue can be used as the MOP for the target UGS.
基金the financial support provide by the National Natural Science Foundation of China(No.52304009)the Natural Science Foundation of Sichuan(No.2023NSFSC0927)the Sichuan Province Innovative Talent Funding Project for Postdoctoral Fellows(No.BX202305)。
文摘Fluid channeling caused by seal failure at the cement sheath-formation interface during fracturing is a severe problem in oil gas wells.In this study,a novel model was developed to evaluate interface sealing integrity.The model's accuracy was verified based on a self-developed interface seal evaluation device and an experiment.Subsequently,the interface seal under different formation conditions was investigated using this model.The theoretical calculation showed that for a cement sheath-carbonate formation interface,the channeling of acid-fracturing fluid caused interface seal failure and sustained casing pressure in the annulus space between the technical casing and formation.Mutual channeling between the fracturing sections occurred at the cement sheathshale formation interface during fracturing.For a sandstone formation,the interface seal failure caused the channeling between a water-bearing formation and a sandstone formation.Aiming at different formation conditions,the mechanical properties requirements of Young's modulus and Poisson's ratio of cement sheath were proposed respectively to ensure its seal integrity.The proposed model and method can be used to evaluate and optimize sealing integrity during fracturing.
文摘Hardfacing of valve sealings in power plants with Inconel 625 alloy has been reviewed in this paper.The overlaying processes,over-lay microstructures,and weldability issues during the hardfacing process have been analyzed.The results indicate that almost all melting welding processes can be used for hardfacing of Inconel 625 alloy.During hardfacing,it is necessary to strictly control the penetration,reduce the overlay dilution rate,so as to prevent the formation of partially mixed zone(PMZ)and solidification crack.From the perspective of controlling the penetration,reducing the overlay dilution rate,and automated hardfacing,the most suitable process for hardfacing Inconel 625 alloy on the valve sealings in power plants is cold metal transfer(CMT)welding process.
文摘In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequently leading to the failure and damage of threaded connections.In severe cases,it can result in considerable economic losses and trigger safety accidents.The sealing performance of special bolted joints holds crucial importance for production efficiency,output,equipment lifespan,and cost control.Enhancing the sealing perfor-mance of threaded connections can have a positive impact on industrial production and environmental protection.The existing research on American Petroleum Institute threaded joints has been thorough and has obtained a series of excellent results.However,the research on the sealing damage mechanism of threaded connections under complex well conditions lacks sufficient depth and that on new sealing technology is scarce.This study proposes a half-size evaluation test to address the abovementioned problem.Based on this test,an investigation into the sealing performance of threaded connections under high-temperature,cyclic loading,and high-temperature creep conditions is conducted.This study uses a combined approach of finite element methods and experiments to investigate the impact of different makeup torques on the sealing performance of premium threaded connections(PTCs).The results of the half-size evaluation test indicate that temperature notably influences the sealing performance of threaded connections.The continuous action of high temperatures causes contact pressure and sealing performance to decrease,and sealing contact pressure increases after cooling.Finite element and test results show that for a certain joint A,the greater the torque,the higher the critical sealing pressure of the thread,and the better the sealing performance.The research on the sealing damage mechanism of PTCs provides a scientific basis and theoretical guidance for the further optimization and development of PTCs.
文摘Manufacturers must identify and classify various defects in automotive sealing rings to ensure product quality.Deep learning algorithms show promise in this field,but challenges remain,especially in detecting small-scale defects under harsh industrial conditions with multimodal data.This paper proposes an enhanced version of You Only Look Once(YOLO)v8 for improved defect detection in automotive sealing rings.We introduce the Multi-scale Adaptive Feature Extraction(MAFE)module,which integrates Deformable ConvolutionalNetwork(DCN)and Spaceto-Depth(SPD)operations.This module effectively captures long-range dependencies,enhances spatial aggregation,and minimizes information loss of small objects during feature extraction.Furthermore,we introduce the Blur-Aware Wasserstein Distance(BAWD)loss function,which improves regression accuracy and detection capabilities for small object anchor boxes,particularly in scenarios involving defocus blur.Additionally,we have constructed a high-quality dataset of automotive sealing ring defects,providing a valuable resource for evaluating defect detection methods.Experimental results demonstrate our method’s high performance,achieving 98.30% precision,96.62% recall,and an inference speed of 20.3 ms.
基金Supported by Guangdong Basic Research Center of Excellence for Major Blinding Eye Diseases Prevention and Treatment(No.2024-YXGG-016).
文摘Dear Editor,We report a surgical method for treating repeat Descemet’s membrane(DM)detachments in two cases with DM micro-perforation during deep anterior lamellar keratoplasty(DALK).DM micro-perforation is a common intraoperative complication that occurs during the performance of DM baring in DALK,using methods such as the bigbubble air technique[1].The sequelae of DM micro-perforations include postoperative DM detachments,higher endothelial cell loss,endothelial decompensation,and transplant interface scarring[2].
基金Supported by Jiangsu Provincial Natural Science Foundation(Grant No.BK20231497)Jiangsu Provincial Post graduate Research&Practice Innovation Program(Grant No.KYCX25_2982)+3 种基金China University of Mining and Technology Graduate Innovation Program(Grant No.2025WLKXJ094)National Natural Science Foundation of China(Grant No.51975573)National Key R&D Program of China(Grant No.2022YFC2905600)Priority Academic Program Development of Jiangsu Higher Education Institute of China.
文摘A rotary sealing device that automatically compensates for wear is designed to address the issues of easy wear and the short service life of the rotary sealing device with automatic wear compensation in mining machinery.After the end face of the guide sleeve wears out,it still tightly adheres to the sealing valve seat under the pressure difference,achieving automatic wear compensation.Based on fluid-solid coupling technology,the structural strength of the rotary sealing device was checked.The influence of factors on the sealing performance of rotary sealing devices was studied using the control variable method.The results show that as the pressure of water increases,the leakage rate of the sealing device decreases,and after 30 MPa,the leakage rate is almost 0 mL/h.The temperature of the rotating sealing device increases with the increase of rotation speed or pressure,and the temperature is more affected by the rotation speed factor.The frictional torque increases with increasing pressure and is independent of rotational speed.Comprehensive analysis shows that the wear resistance and reliability level of the sealing guide sleeve material is PVDF>PEEK>PE>PA.This study designs a high-pressure automatic compensation wear rotary sealing device and selects the optimal sealing material,providing technical support for the application of high-pressure water jet in mining machinery.
基金Supported by National Hi-tech Research and Development Program of China(863 Program,Grant No.2012AA09A205)
文摘The metal sealing performance of subsea X-tree wellhead connectors is crucial for the safety and reliability of subsea X-trees. In order to establish the theoretical relation between metal sealing ring＇s contact stress and its structural parameters and working pressure, a mechanical analysis method for double-cone sealing of high pressure vessels is applied in analyzing the metal sealing ring under the condition of preload and operation. As a result, the formula of the unit sealing load for the metal sealing ring under operation with residual preload is shown in this paper, which ensures that the metal sealing ring has an excellent sealing effect and can prevent the metal sealing ring from yielding. Besides, while analyzing the sealing process of the metal sealing ring, the change rule of contact stress and working pressure is concluded here, putting forward that the structural parameters of the metal sealing ring are the major factors affecting the change rule. Finally, the analytical solution through theoretical analysis is compared with the simulation result through finite element analysis in a force feedback experiment, and both are consistent with each other, which fully verifies for the design and calculation theory on metal sealing ring＇s contact stress and its structural parameters and working pressure deduced in this paper. The proposed research will be treated as an applicable theory guiding the design of metal seal for subsea X-tree wellhead connectors.
基金National Natural Science Foundation of China(No.51175481)
文摘In order to speed underwater launch of minor-caliber weapons,a sealing device can be set in front of underwater muzzle to separate water,preventing the muzzle from water immersion.By establishing and simplifying the model of underwater weapon sealing device and unstructured mesh computing domain model based on computational fluid dynamics（CFD）,dynamic mesh and user defined function（UDF）,the N-S equation is solved and the numerical analysis and calculation of the complex two-phase flow inside the sealing device are carried out.The results show that the gas discharged from the sealing device is conducive to the formation of the projectile supercavity.When the projectile is launched at 5munder water,the shock wave before and after the projectile has impact on the box body up to 100 MPa,therefore the sealing device must be strong enough.The research results have the vital significance to the design of underwater weapon sealing device and the formation of the projectile supercavitation.
基金Supported by National Natural Science Foundation of China(Grant Nos.51279042,51105088)
文摘Researchers seldom study the optimum design of a mechanical connector for subsea oil-gas pipeline based upon the sealing performance. An optimal design method of a novel subsea pipeline mechanical connector is presented. By analyzing the static metal sealing mechanism, the critical condition of the sealing performance is established for this connector and the formulation method of the contact pressure on the sealing surface is created. By the method the minimum mean contact pressure of the 8.625 inch connector is calculated as 361 MPa, which is the constraint condition in the optimum design of connector.The finite element model is created in ANSYS Parametric Design Language(APDL) and the structure is optimized by the zero-order method, with variance of contact pressure as the objective function, and mean contact pressures and plastic strains as constraint variables. The optimization shows that variances of contact pressure on two sealing surfaces decrease by 72.41% and 89.33%, respectively, and mean contact pressures increase by 31.18% and 52.84%, respectively. The comparison of the optimal connectors and non-optimal connectors in the water pressure experiments and bending experiments shows that the sealing ability of optimized connectors is much higher than the rated pressure of 4.5 MPa, and the optimal connectors don’t leak under the bending moment of 52.2 kN·m.This research provides the formulation to solve contact pressure on the sealing surface and a structure optimization method to design the connectors with various dimensions.
文摘Lost circulations have presented great challenges to the petroleum industry, causing great expenditures of cash and time to fighting the problem. Probably the most problematic situations are the naturally fractured formations where the operator may face total loss with no mud return in the annular. The voids or large fracture encountered in this case are often far too large to be plugged with conventional Lost Circulation Material. This paper will give a detailed introduction on a novel composite gel material usable to control severe losses and pressurization sealing. The plugging mechanics of this new composite gel material, which is different from conventional lost circulation materials, were elaborated as well. In addition, the properties of the new composite gel material such as thermostability, sealing strength and bearing resistance are characterized with specific experimental devices. The experimental results proved that the breakdown pressure of the new plugging reached more than 20MPa, and the maximum degraded temperature can be exceed 130℃. The field application at 4 wells in Puguang gas field, SINOPEC, demonstrated that the new composite gel material solved the serious loss in Ordovician carbonate fractured formation successfully and guaranteed the following completion cement operation smoothly. The composite gel sealing slurries, which was easily prepared on site, gives remarkable properties regarding pumping through drill pipes, adjustment of setting time and excellent sealing strength of the lost zone sealing, additionally, the whole pressurization sealing process was complicated within only ten hours. The on-site results show that the plugging ratio of the new composite gel was reached 100%, and the success rate of sealing operation kept above 80%.Thus the new LCM can guarantee safe drilling jobs and save operation cost more effectively.
文摘It is of great significance to study the controlling effect of sealing systems on CBM enrichment in coalbed methane (CBM) exploration anddevelopment. In this paper, the relationships between CBM enrichment and geological elements were analyzed. The geological elements includesealing layers (e.g. regional cap rock, regional floor, and immediate roof and floor), later structural adjustment and strata production status. It isshown that CBM tends to enrich in the areas where regional mudstone cap rocks and floors are distributed stably, structures are uplifted andinversed slightly after the hydrocarbon accumulation period and the strata is gentle in a balanced state. Then, the concept of sealing system wasput forward based on the worldwide CBM exploration and development practices over the years. A sealing system refers to a geological unitcomposed of a lateral stable zone and cap rock which prevents gas from migrating upward and downward. In a sealing system, CBM can getenriched and coal-measure gas can also be accumulated. Finally, three gas reservoir types (i.e., sandwich-type CBM reservoir, associated CBM-sandstone gas reservoir and coal-derived sandstone gas reservoir) were identified based on the configuration relationships between elements ofthe CBM (or coal-measure gas) sealing system. It is recommended to change the exploration ideas from simple CBM exploration to 3D CBMand coal-measure gas exploration. In addition, an evaluation index system of CBM (or coal-measure gas) geological selection was established. Itis pointed out that good application effects may be realized if the stereoscopic CBM and coal-measure gas exploration is applied in the JunggarBasin and the eastern margin of the Ordos Basin.
