Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migra...Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.展开更多
The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the ...The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evaluating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(Ⅰ)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.展开更多
Determining the venting time of a gas trunk pipeline segment provides an important basis for formulating an emergency plan in the advent of unexpected accidents.As the natural gas venting process corresponds to the tr...Determining the venting time of a gas trunk pipeline segment provides an important basis for formulating an emergency plan in the advent of unexpected accidents.As the natural gas venting process corresponds to the transient flow,it is necessary to establish a transient hydraulic-thermal simulation model in order to determine the venting time.In this paper,based on two kinds of venting scenarios in which there is only one venting point in the venting system of a gas trunk pipeline segment—namely,where the venting point is either at one of the two ends or at the junction of two gas trunk pipeline segments—transient hydraulic-thermal simulation models are established.The models consist of gas flow governing equations,the gas state equation,gas physical property equations,initial conditions,and appropriate boundary conditions.The implicit central difference method is used to discretize the gas flow partial differential equations,and the trust-region-dogleg algorithm is used to solve the equations corresponding to each time step,in order to dynamically simulate the whole venting process.The judgment condition for the end of the venting process is that the average pressure of gas trunk pipeline segment is less than 0.11 MPa(actual pressure).Comparing the simulation results of the proposed model with those of the OLGA software and real operational data,we find that the venting time error is less than 10%.On this basis,a venting valve opening control principle is proposed,which prevents the venting noise from exceeded the specified noise value(85 d B)in the venting design of domestic gas pipeline projects.The established calculation model for venting time(dynamic simulation model)for a gas trunk pipeline segment and the proposed opening control principle of venting valve provide reference for the optimal operation of gas pipeline venting systems.展开更多
A left ventricular (LV) pseudoaneurysm is one of the complications of acute myocardial infarction. It is also reported after chest trauma, cardiac surgery, and endocarditis. We report a rare case of an LV pseudoaneury...A left ventricular (LV) pseudoaneurysm is one of the complications of acute myocardial infarction. It is also reported after chest trauma, cardiac surgery, and endocarditis. We report a rare case of an LV pseudoaneurysm induced by an LV venting catheter through the right superior pulmonary vein during thoracic aortic surgery. A 77-year-old man was referred for surgical repair of a distal aortic arch aneurysm. He underwent total aortic arch reconstruction with the frozen elephant trunk technique. The early postoperative period was uneventful. Postoperative contrast computed tomography and transthoracic echocardiography (TTE) revealed a pseudoaneurysm with a narrow neck at the apex of the LV that had sub-clinically progressed. Because of the risk of spontaneous rupture, an urgent aneurysmectomy was performed via a repeat sternotomy. Under cardioplegic arrest, the pseudoaneurysm was opened and the small orifice, which communicated with the LV, was confirmed. No myocardial ischemic changes were observed around the orifice. The pseudoaneurysm was thought to be induced by endocardial laceration by the tip of the venting catheter. The pseudoaneurysm was closed by linear repair reinforced with felt strips. The patient recovered well and was discharged 18 days after the second surgery. TTE showed no recurrence of LV aneurysm at the last follow-up.展开更多
The AREVA FCVS (filtered containment venting system) is a product family that minimizes the environmental impact incase of a severe accident in a nuclear power plant. It is based on a large-scale test and qualificat...The AREVA FCVS (filtered containment venting system) is a product family that minimizes the environmental impact incase of a severe accident in a nuclear power plant. It is based on a large-scale test and qualification program as well as on the design,licensing and installation of more than 80 projects worldwide. The product family provides flexibility regarding adaptation toaccident scenarios, applicable codes and standards, seismic design, supply chain, implementation and localization. AREVA has broadexperience in managing fleet supplies, successful licensing support and cooperation with original equipment manufacturers ofpressurized and boiling water reactors.展开更多
The process of explosion venting to air in a cylindrical vent vessel connected to a duct, filling with a stoichiometric methane-oxygen gas mixture, was simulated numerically by using a colocated grid SIMPLE scheme bas...The process of explosion venting to air in a cylindrical vent vessel connected to a duct, filling with a stoichiometric methane-oxygen gas mixture, was simulated numerically by using a colocated grid SIMPLE scheme based on k-epsilon turbulent model and Eddy-dissipation combustion model. The characteristics of the combustible cloud, flame and pressure distribution in the external flow field during venting were analyzed in terms of the predicted results.The results show that the external explosion is generated due to violent turbulent combustion in the high pressure region within the external combustible cloud ignited by a jet flame. And the turbulence and vortex in the external flow field were also discussed in detail. After the jet flame penetrating into the external combustible cloud, the turbulent intensity is greater in the regions with greater average kinetic energy gradient, rather than in the flame front; and the vortex in the external flow field is generated primarily due to the baroclinic effect, which is greater in the regions where the pressure and density gradients are nearly perpendicular.展开更多
Prolonged cardiorespiratory support can be achieved with ECMO that may provide time for myocardial recovery, prevent multiorgan dysfunction and reduce mortality. Left ventricle (LV) distension can worsen already diste...Prolonged cardiorespiratory support can be achieved with ECMO that may provide time for myocardial recovery, prevent multiorgan dysfunction and reduce mortality. Left ventricle (LV) distension can worsen already distended and hypocontractile heart. Early recognition and aggressive management of LV distension are essential for the treatment of patients with low cardiac output. The case report presented intends to show advantages of left ventricular venting on ECMO after post-cardiotomy shock. With direct flow measurements on bypass-grafts before and after the vent implantation, it was possible to clearly demonstrate the importance of venting for myocardial perfusion.展开更多
VELA■呼吸机可进行有创和无创通气,适用于急诊病房、重症监护病房(intensive care unit,ICU)、普通病房使用,最小潮气量可至50 mL,适合于儿童患者。内置涡轮依据主板校准数据精准运行,还可根据使用环境进行校准补偿,尤其是在高海拔地区...VELA■呼吸机可进行有创和无创通气,适用于急诊病房、重症监护病房(intensive care unit,ICU)、普通病房使用,最小潮气量可至50 mL,适合于儿童患者。内置涡轮依据主板校准数据精准运行,还可根据使用环境进行校准补偿,尤其是在高海拔地区^([1]),扩大了呼吸机的应用范围。展开更多
Venting is the common safety measure to protect plant equipment against excessive overpressure. So far, scenarios in which particles were part of the system and should have been accounted for did ignore their presence...Venting is the common safety measure to protect plant equipment against excessive overpressure. So far, scenarios in which particles were part of the system and should have been accounted for did ignore their presence; the scenarios were treated like a two-phase system. Current research shows that particles can have a major influence on the venting behaviour. Experimental results indicate that particles affect level swell and relief flow especially of foamy systems. Based on those results four different layers of influence of the particle have been identified and are presented in a first model. Based on this model recommendations for the development of new and more complex models are given.展开更多
Background In High Energy Photon Source(HEPS)the beam vacuum pipes employ TiZrVHf non-evaporable getter(NEG)coatings in order to meet the operation requirements.In many occasions it is inevitable to bring the sectors ...Background In High Energy Photon Source(HEPS)the beam vacuum pipes employ TiZrVHf non-evaporable getter(NEG)coatings in order to meet the operation requirements.In many occasions it is inevitable to bring the sectors to atmosphere in order to open detectors,insert or change faulty parts.Consequently,NEG coatings will be saturated and followed with activation to restore the vacuum.Such an intervention would require heating up the whole sector to hundreds of degree and last from 2 to 4 weeks.Purpose Therefore,a Neon venting system is developed in HEPS in order to perform fast interventions without losing much of the performance of the activated NEG coating.Methods Preliminary experiments has been carried out to test the venting with Neon of different purity by comparing pumping speed lost and vacuum recovery before and after Neon venting.Results Results show that Neon with ultrahigh purity(purified by NEG cartridge purifier)could preserve full pumping performance of the NEG coated pipes.Neon with 6 N purity could preserve half pumping performance of the NEG coated pipes,but vacuum could be fully restored in only 2 days.Neon with 5 N purity could saturate the NEG coated pipes,leading to full pumping performance lost.Therefore,Neon with 6 N purity or above is promising in applications of efficient operations in HEPS.展开更多
A surface micro-/nano-structured metal plate can be joined with an injection molded plastic piece in a mold,which has been named injection molded direct joining(IMDJ).The injected plastic melt infiltrates the micro-/n...A surface micro-/nano-structured metal plate can be joined with an injection molded plastic piece in a mold,which has been named injection molded direct joining(IMDJ).The injected plastic melt infiltrates the micro-/nano-structure,e.g.,a porous structure with micro/nano pores,on the metal plate while flowing in the mold cavity where the metal plate is inserted.After solidification of the plastic,the metal and plastic materials are directly joined via the micro-/nano-structured metal surface.Since air is trapped by the plastic melt,it is easily imagined that the air in the mold cavity prevents the melt plastic from contacting the metal surface and infiltrating the micro-/nano-structure,which could result in poorer joining performance.To avoid the prevention of the air for the better joining performance,the present study proposes a system actively venting the mold cavity during injection molding.To apply the active venting to IMDJ,venting and sealing systems were newly developed.In addition,a system measuring air pressure of the mold cavity was developed.The proposed system was evaluated by a measurement of joining strengths of IMDJ specimens that were produced under various conditions.From the results,it is concluded that the active venting does not necessarily have a positive effect in any cases:the effect depends on the type of surface micro-/nano-structure.展开更多
Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-...Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-dimensional magneto-hydrodynamic (MHD) model of arc in a low voltage circuit breaker. The effects of the arc ignition location, venting size and gassing material on arc behavior have been investigated. The analysis of the results show that the arc velocity accelerates with the increase in the distance between arc ignition location and of the venting size, and the existence of the gassing material is beneficial to improving the arc voltage and reducing the arc temperature.展开更多
The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the d...The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the dependence on the venting system complicates the mould design. Furthermore in certain condition, it is difficult to integrate the venting system into the mould. Currently a kind of mold material which has gas permeability has been developed in abroad, but the applications of this mold material were restricted by its higher cost and smaller size. In this research, a porous material which was made by powder metallurgy was applied to plastic mould to replace the venting system. Permeability of the steel with different secondary processing was tested and compared with a special apparatus. The metallographic samples of the steel with different secondary processing were prepared and investigated. Finally an actual injection set was established to investigate the applications of permeable steel. The metallographies indicate that the micro-holes inside permeable steel were interconnected. Moulds made of permeable steel exhibit good permeability in the plastic-injection experiments and gas generated in the mould cavity was smoothly exhausted. The melted plastic did not penetrate into the mould or block in the micro-holes. After several times of plastic-injection experiments, the mould still retained good permeability. The strength of this permeable steel is between 200–250 MPa and suitable for industrial applications. The venting systems simplified by permeable steel in plastic-injection have simple structures, which can be applied into any place that requires gas exhausting.展开更多
There is a fairly strict relation between maximum tsunami wave heights and causation earthquake magnitudes. This provides a new tool for estimating the magnitude of past earthquakes from the observed wave heights of r...There is a fairly strict relation between maximum tsunami wave heights and causation earthquake magnitudes. This provides a new tool for estimating the magnitude of past earthquakes from the observed wave heights of related paleo-tsunami events. The method is subjected to a test versus two paleoseismic events with multiple independent estimates of corresponding earthquake magnitude. The agreement to the tsunami wave height conversion is good, confirming very high magnitudes of M 8.5 - 9.0 and M 8.4 - 8.5. Applying the same method to two Late Holocene events of methane venting tectonics indicates a ground shaking of forces equivalent to a M 8.0 earthquake, seriously changing previous long-term crustal hazard assessments.展开更多
A meteorite impacted the ground in Estonia forming the Kaali Crater dated at 1183 - 1162 BC. It set up a Baltic-wide mega-tsunami dated at 1171 absolute varve years BC. It also triggered violent seismotectonic effect ...A meteorite impacted the ground in Estonia forming the Kaali Crater dated at 1183 - 1162 BC. It set up a Baltic-wide mega-tsunami dated at 1171 absolute varve years BC. It also triggered violent seismotectonic effect in Sweden. Ancient legends testify of direct observations of the sky phenomena and personal experiences of the ground shaking and tsunami flooding, which makes the Kaali Crater the oldest impact event documented by humans. The Ragnar<span style="white-space:nowrap;">ö</span>k apocalypse is likely to lead its origin from the violent geodynamic activity along the Swedish east coast.展开更多
基金supported by the National Natural Science Foundation of China(42376221,42276083)Director Research Fund Project of Guangzhou Marine Geological Survey(2023GMGSJZJJ00030)+2 种基金National Key Research and Development Program of China(2021YFC2800901)Guangdong Major Project of Basic and Applied Basic Research(2020B030103003)the project of the China Geological Survey(DD20230064).
文摘Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.
基金supported by the National Key R&D Program of China(No.2021YFB2402001)the Postgraduate Innovation and Entrepreneurship Practice Project of Anhui Province(No.2022cxcysj013)+2 种基金the China Postdoctoral Science Foundation(No.2022T150615)the Fundamental Research Funds for the Central Universities(No.WK5290000002)supported by Youth Innovation Promotion Association CAS(No.Y201768)。
文摘The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evaluating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(Ⅰ)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.
基金supported by the National Natural Science Foundation of China(Grant No.52174064)
文摘Determining the venting time of a gas trunk pipeline segment provides an important basis for formulating an emergency plan in the advent of unexpected accidents.As the natural gas venting process corresponds to the transient flow,it is necessary to establish a transient hydraulic-thermal simulation model in order to determine the venting time.In this paper,based on two kinds of venting scenarios in which there is only one venting point in the venting system of a gas trunk pipeline segment—namely,where the venting point is either at one of the two ends or at the junction of two gas trunk pipeline segments—transient hydraulic-thermal simulation models are established.The models consist of gas flow governing equations,the gas state equation,gas physical property equations,initial conditions,and appropriate boundary conditions.The implicit central difference method is used to discretize the gas flow partial differential equations,and the trust-region-dogleg algorithm is used to solve the equations corresponding to each time step,in order to dynamically simulate the whole venting process.The judgment condition for the end of the venting process is that the average pressure of gas trunk pipeline segment is less than 0.11 MPa(actual pressure).Comparing the simulation results of the proposed model with those of the OLGA software and real operational data,we find that the venting time error is less than 10%.On this basis,a venting valve opening control principle is proposed,which prevents the venting noise from exceeded the specified noise value(85 d B)in the venting design of domestic gas pipeline projects.The established calculation model for venting time(dynamic simulation model)for a gas trunk pipeline segment and the proposed opening control principle of venting valve provide reference for the optimal operation of gas pipeline venting systems.
文摘A left ventricular (LV) pseudoaneurysm is one of the complications of acute myocardial infarction. It is also reported after chest trauma, cardiac surgery, and endocarditis. We report a rare case of an LV pseudoaneurysm induced by an LV venting catheter through the right superior pulmonary vein during thoracic aortic surgery. A 77-year-old man was referred for surgical repair of a distal aortic arch aneurysm. He underwent total aortic arch reconstruction with the frozen elephant trunk technique. The early postoperative period was uneventful. Postoperative contrast computed tomography and transthoracic echocardiography (TTE) revealed a pseudoaneurysm with a narrow neck at the apex of the LV that had sub-clinically progressed. Because of the risk of spontaneous rupture, an urgent aneurysmectomy was performed via a repeat sternotomy. Under cardioplegic arrest, the pseudoaneurysm was opened and the small orifice, which communicated with the LV, was confirmed. No myocardial ischemic changes were observed around the orifice. The pseudoaneurysm was thought to be induced by endocardial laceration by the tip of the venting catheter. The pseudoaneurysm was closed by linear repair reinforced with felt strips. The patient recovered well and was discharged 18 days after the second surgery. TTE showed no recurrence of LV aneurysm at the last follow-up.
文摘The AREVA FCVS (filtered containment venting system) is a product family that minimizes the environmental impact incase of a severe accident in a nuclear power plant. It is based on a large-scale test and qualification program as well as on the design,licensing and installation of more than 80 projects worldwide. The product family provides flexibility regarding adaptation toaccident scenarios, applicable codes and standards, seismic design, supply chain, implementation and localization. AREVA has broadexperience in managing fleet supplies, successful licensing support and cooperation with original equipment manufacturers ofpressurized and boiling water reactors.
文摘The process of explosion venting to air in a cylindrical vent vessel connected to a duct, filling with a stoichiometric methane-oxygen gas mixture, was simulated numerically by using a colocated grid SIMPLE scheme based on k-epsilon turbulent model and Eddy-dissipation combustion model. The characteristics of the combustible cloud, flame and pressure distribution in the external flow field during venting were analyzed in terms of the predicted results.The results show that the external explosion is generated due to violent turbulent combustion in the high pressure region within the external combustible cloud ignited by a jet flame. And the turbulence and vortex in the external flow field were also discussed in detail. After the jet flame penetrating into the external combustible cloud, the turbulent intensity is greater in the regions with greater average kinetic energy gradient, rather than in the flame front; and the vortex in the external flow field is generated primarily due to the baroclinic effect, which is greater in the regions where the pressure and density gradients are nearly perpendicular.
文摘Prolonged cardiorespiratory support can be achieved with ECMO that may provide time for myocardial recovery, prevent multiorgan dysfunction and reduce mortality. Left ventricle (LV) distension can worsen already distended and hypocontractile heart. Early recognition and aggressive management of LV distension are essential for the treatment of patients with low cardiac output. The case report presented intends to show advantages of left ventricular venting on ECMO after post-cardiotomy shock. With direct flow measurements on bypass-grafts before and after the vent implantation, it was possible to clearly demonstrate the importance of venting for myocardial perfusion.
文摘Venting is the common safety measure to protect plant equipment against excessive overpressure. So far, scenarios in which particles were part of the system and should have been accounted for did ignore their presence; the scenarios were treated like a two-phase system. Current research shows that particles can have a major influence on the venting behaviour. Experimental results indicate that particles affect level swell and relief flow especially of foamy systems. Based on those results four different layers of influence of the particle have been identified and are presented in a first model. Based on this model recommendations for the development of new and more complex models are given.
基金The funding was provided by National Development and Reform Commission Grand No.((2017)2173).
文摘Background In High Energy Photon Source(HEPS)the beam vacuum pipes employ TiZrVHf non-evaporable getter(NEG)coatings in order to meet the operation requirements.In many occasions it is inevitable to bring the sectors to atmosphere in order to open detectors,insert or change faulty parts.Consequently,NEG coatings will be saturated and followed with activation to restore the vacuum.Such an intervention would require heating up the whole sector to hundreds of degree and last from 2 to 4 weeks.Purpose Therefore,a Neon venting system is developed in HEPS in order to perform fast interventions without losing much of the performance of the activated NEG coating.Methods Preliminary experiments has been carried out to test the venting with Neon of different purity by comparing pumping speed lost and vacuum recovery before and after Neon venting.Results Results show that Neon with ultrahigh purity(purified by NEG cartridge purifier)could preserve full pumping performance of the NEG coated pipes.Neon with 6 N purity could preserve half pumping performance of the NEG coated pipes,but vacuum could be fully restored in only 2 days.Neon with 5 N purity could saturate the NEG coated pipes,leading to full pumping performance lost.Therefore,Neon with 6 N purity or above is promising in applications of efficient operations in HEPS.
基金This study was supported by JSPS KAKENHI(#17J00345)and the Foundation for the Promotion of Industrial Science.A part of the experiments was carried out with the supports and advices of Yokoi group,the University of Tokyo,Japan.
文摘A surface micro-/nano-structured metal plate can be joined with an injection molded plastic piece in a mold,which has been named injection molded direct joining(IMDJ).The injected plastic melt infiltrates the micro-/nano-structure,e.g.,a porous structure with micro/nano pores,on the metal plate while flowing in the mold cavity where the metal plate is inserted.After solidification of the plastic,the metal and plastic materials are directly joined via the micro-/nano-structured metal surface.Since air is trapped by the plastic melt,it is easily imagined that the air in the mold cavity prevents the melt plastic from contacting the metal surface and infiltrating the micro-/nano-structure,which could result in poorer joining performance.To avoid the prevention of the air for the better joining performance,the present study proposes a system actively venting the mold cavity during injection molding.To apply the active venting to IMDJ,venting and sealing systems were newly developed.In addition,a system measuring air pressure of the mold cavity was developed.The proposed system was evaluated by a measurement of joining strengths of IMDJ specimens that were produced under various conditions.From the results,it is concluded that the active venting does not necessarily have a positive effect in any cases:the effect depends on the type of surface micro-/nano-structure.
基金The project supported by National Natural Science Foundation of China (No. 50507016) and the Specialized Research Fund forthe Doctoral Program of Higher Education (No. 20020698008) and the Doctorate Foundation of Xi'an Jiaotong University
文摘Taking into account the properties of the arc plasma and the electromagnetic, heat and radiative phenomena, commercial computational fluid dynamics software PHOENICS has been adapted and modified to develop the three-dimensional magneto-hydrodynamic (MHD) model of arc in a low voltage circuit breaker. The effects of the arc ignition location, venting size and gassing material on arc behavior have been investigated. The analysis of the results show that the arc velocity accelerates with the increase in the distance between arc ignition location and of the venting size, and the existence of the gassing material is beneficial to improving the arc voltage and reducing the arc temperature.
基金supported by Guangdong-Hong Kong Key Project of China (Grant No. 2007Z010)National Basic Research Program of China (973 Program, Grant No. 2007CB616905)
文摘The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the dependence on the venting system complicates the mould design. Furthermore in certain condition, it is difficult to integrate the venting system into the mould. Currently a kind of mold material which has gas permeability has been developed in abroad, but the applications of this mold material were restricted by its higher cost and smaller size. In this research, a porous material which was made by powder metallurgy was applied to plastic mould to replace the venting system. Permeability of the steel with different secondary processing was tested and compared with a special apparatus. The metallographic samples of the steel with different secondary processing were prepared and investigated. Finally an actual injection set was established to investigate the applications of permeable steel. The metallographies indicate that the micro-holes inside permeable steel were interconnected. Moulds made of permeable steel exhibit good permeability in the plastic-injection experiments and gas generated in the mould cavity was smoothly exhausted. The melted plastic did not penetrate into the mould or block in the micro-holes. After several times of plastic-injection experiments, the mould still retained good permeability. The strength of this permeable steel is between 200–250 MPa and suitable for industrial applications. The venting systems simplified by permeable steel in plastic-injection have simple structures, which can be applied into any place that requires gas exhausting.
文摘There is a fairly strict relation between maximum tsunami wave heights and causation earthquake magnitudes. This provides a new tool for estimating the magnitude of past earthquakes from the observed wave heights of related paleo-tsunami events. The method is subjected to a test versus two paleoseismic events with multiple independent estimates of corresponding earthquake magnitude. The agreement to the tsunami wave height conversion is good, confirming very high magnitudes of M 8.5 - 9.0 and M 8.4 - 8.5. Applying the same method to two Late Holocene events of methane venting tectonics indicates a ground shaking of forces equivalent to a M 8.0 earthquake, seriously changing previous long-term crustal hazard assessments.
文摘A meteorite impacted the ground in Estonia forming the Kaali Crater dated at 1183 - 1162 BC. It set up a Baltic-wide mega-tsunami dated at 1171 absolute varve years BC. It also triggered violent seismotectonic effect in Sweden. Ancient legends testify of direct observations of the sky phenomena and personal experiences of the ground shaking and tsunami flooding, which makes the Kaali Crater the oldest impact event documented by humans. The Ragnar<span style="white-space:nowrap;">ö</span>k apocalypse is likely to lead its origin from the violent geodynamic activity along the Swedish east coast.