The Shenhu Area in the South China Sea is rich in oil and gas resources and has many vertical gas chimneys,making it an excellent geological environment for hydrate accumulation.This paper examines the geological cond...The Shenhu Area in the South China Sea is rich in oil and gas resources and has many vertical gas chimneys,making it an excellent geological environment for hydrate accumulation.This paper examines the geological conditions governing these gas-chimneys.A numerical simulation method based on the partial-equilibrium reaction model of hydrate was applied to simulate the migration of methane gas and the resultant hydrate formation when the gas enters the hydrate stability zone under the seabed through gas-chimneys.The dynamics of this gaschimney hydrate accumulation were analyzed,and the influences of different factors―namely,the fluid supply time,rate,and temperature―on the formation temperature and ultimate distribution of the hydrate reservoir were evaluated.The simulation results indicate that the accumulation of hydrate via gas-chimneys is significantly affected by the temperature of the gas source,the transfer state of the methane gas,and the number of cycles of alternating gas-water invasion.Hydrate accumulation takes shape in an annular or semi-annular distribution pattern divided by fluid state as follows:a two-phase gas-water zone,a three-phase gas-water-hydrate zone,a two-phase water-hydrate zone,and a phase of water passing from the inside to the outside.Formation inclination and reservoir heterogeneity can greatly affect the distribution shape and abundance of the hydrate.A high fluid supply temperature,frequent alternating invasions of gas and water,and long-term pore-water invasion at a high rate can jointly cause a large central hydrate-free zone.In contrast,a long-term supply shutdown during the alternating gas-water invasion process,and a high gas rate with a low water rate in the gas-dominant invasion stage,foster the accumulation of hydrate in great abundance and with considerable thickness.The results of this study can help us understand the accumulation of hydrate through gas chimneys in the Shenhu Area.展开更多
Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study,...Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.展开更多
Gas chimneys,salt domes,and faults are vital to the movement of hydrocarbons within geological systems.Accurate identification of these geological features is crucial to modeling hydrocarbon resources.This study explo...Gas chimneys,salt domes,and faults are vital to the movement of hydrocarbons within geological systems.Accurate identification of these geological features is crucial to modeling hydrocarbon resources.This study explores the processes that have shaped the eastern Persian Gulf,focusing on salt diapir characteristics,origin,and fluid migration.Plate collisions between the Indian,Eurasian,and Arabian Plates have considerably impacted salt tectonics,developing key features such as the Hormuz salt,Qatar-South Fars Arch,and Zagros and Oman orogenic structures.Salt-related features were discerned through two-dimensional seismic data and drilling records,salt movement sequences were reconstructed,and fluid expulsion patterns were delineated using attribute preferences.The results of this study revealed that fractured substrates influenced by regional tectonic forces contribute to the creation of salt diapirs,which serve as conduits for guided fluid transport.Moreover,these results showed that gravity-driven downbuilding mainly controls salt flow,while the circular arrangement of salt structures results from regional stress and interactions between different salt sources.Distinct stress-induced basement incisions compounded by the hindrance of initial salt movement by the Qatar Arch further contribute to the complex salt structure geometry.Crucially,the uplift of the Qatar Arch and stresses from the Oman and Zagros orogenies profoundly affect the salt structure geometry and depositional patterns across diverse regions,resulting in circular salt structures and gas chimneys.This study offers valuable perspectives for oil and gas exploration and provides a comprehensive understanding of the regional dynamics governing salt tectonics and hydrocarbon ascent in the eastern Persian Gulf.展开更多
目的:总结Chimney支架技术联合All in One技术在经导管主动脉瓣置换术(TAVR)中应用的初步经验。方法:收集2021年7月至2022年7月首都医科大学附属北京安贞医院心脏瓣膜病介入中心在TAVR术中联合应用Chimney支架技术和All in One技术的10...目的:总结Chimney支架技术联合All in One技术在经导管主动脉瓣置换术(TAVR)中应用的初步经验。方法:收集2021年7月至2022年7月首都医科大学附属北京安贞医院心脏瓣膜病介入中心在TAVR术中联合应用Chimney支架技术和All in One技术的10例患者进行回顾性分析,总结临床资料、影像学资料、手术操作、住院和出院随访期间主要不良心脑血管事件的发生情况。结果:10例患者中男性4例,女性6例,平均年龄(76.2±3.9)岁,三叶式主动脉瓣7例,二叶式主动脉瓣3例,术前CT评估均有冠状动脉阻塞危险因素,并且术中球囊预扩张提示冠状动脉阻塞。所有患者均使用一枚药物洗脱支架完成Chimney支架技术,冠状动脉支架置入有8例位于左主干,2例位于右冠状动脉,支架平均直径(3.7±0.3)mm,平均长度(20.6±2.4)mm,在住院及平均随访(7.8±3.7)个月期间,无死亡、心肌梗死、脑卒中等主要不良心脑血管事件发生。结论:TAVR术中Chimney支架技术联合All in One技术安全可行。展开更多
An extinct hydrothermal barite-silica chimney from the Franklin Seamount of the Woodlark Basin, in the southwestern Pacific Ocean, was investigated for mineral distribution and geochemical composition. Six layers on e...An extinct hydrothermal barite-silica chimney from the Franklin Seamount of the Woodlark Basin, in the southwestern Pacific Ocean, was investigated for mineral distribution and geochemical composition. Six layers on either side of the orifice of a chimney show significant disparity in color, mineral assemblage and major element composition. Electron microscope（SEM） images reveal that the peripheral wall of the chimney is composed of colloform silica, suggesting that incipient precipitation of silica-saturated hydrothermal fluid initiated the development of the chimney wall. Intermediate layers, between the exterior wall and the inner fluid-orifice, dominate with barite and sulfides. Low Sr-to-Ba ratios（SrO/BaO = 0.015–0.017） indicate restricted fluid-seawater mixing, which causes relatively high-temperature formation of the intermediate layers. Whereas the innermost layer bordering the chimney orifice is characterized by more silica and a higher Sr-to-Ba ratio（SrO/BaO = 0.023）, could have formed due to a paragenetic shift from a high-temperature active phase to a cooler waning stage of formation. A paragenetic shift is also probably responsible for the change in mineral formation mechanism that resulted in the textural variation of barite and colloform silica developed during different growth phases of this barite-silica chimney.展开更多
Hydrothermal chimney is a product of hydrothermal activity on the seabed. Chimney samples dredged from Jade hydrothermal area in Izena depression of the Okinawa Trough, are characterized by relatively enriched light r...Hydrothermal chimney is a product of hydrothermal activity on the seabed. Chimney samples dredged from Jade hydrothermal area in Izena depression of the Okinawa Trough, are characterized by relatively enriched light rare earth elements (LREE) and strongly positive Eu anomalies. 87Sr/86Sr and 143Nd/144Nd of these samples are exactly between those of seawater and of acidic pumice, averaged at 0.708928 and 0.512292, respectively. These characteristics imply that the main source of hydrothermal sulfide at Jade area is possibly the undersurface acidic rocks. The mineralizing mechanism can be summarized as follows: Large amount of mineralized material would be leached out and LREE-enriched hydrothermal solution would be subsequently produced as a result of thermo-chemical exchange reaction between acidic volcanic rocks and heated seawater that penetrated in advance from upper water mass. The spurting out from the seabed and quickly crystallizing in the seawater of hydrothermal solution are responsible for the formation of Cu-Zn sulfide and barite-amorphous SiO2 minerals that are characterized by enriched LREE and positively strong Eu anomalies.展开更多
A sulfide black smoker chimney exists in the Gaobanhe seabed exhalation massive sulfide deposit in the Xingiong-Kuancheng secondary fault basin of the Proterozoic Yaniiao rift trough in Hebei Province, taking the shap...A sulfide black smoker chimney exists in the Gaobanhe seabed exhalation massive sulfide deposit in the Xingiong-Kuancheng secondary fault basin of the Proterozoic Yaniiao rift trough in Hebei Province, taking the shape of mounds, individually about 2-3 cm high. Abundant fossils of thermophilous bacteria and algae in perfect preservation are found in the ore surrounding the black smoker chimney. Scanning electron microscopy （SEM） and molecular biomarker studies on the microorganismai ore fabric show that the microorganism in the sulfide ore is in fact a sedimentary product of probiotic bacteria and algae. In the special food chain based on black smoker chimney at ancient seabed- thermophilous bacteria, the thermophilous bacteria and algae reproduce in large quantity. Intermittently erupting of fluid from the chimney creats conditions for formation of sulfide deposit. In the process of exhalation action of hot fluid, thermophilous bacteria and algae grow and reproduce around the sulfide black smoker chimney, absorbing mineralizing substances brought by the fluid. Massive sulfide deposits are formed in this process of absorption of seabed black smoker chimney exhalation-mineralizing fluid pulsation-thermophilous microorganism.展开更多
Introduction:Parallel stent-stent grafting is a major endovascular technique used to preserve the supra-aortic branches during thoracic endovascular aortic repair(TEVAR)of aortic pathologies involving the aortic arch....Introduction:Parallel stent-stent grafting is a major endovascular technique used to preserve the supra-aortic branches during thoracic endovascular aortic repair(TEVAR)of aortic pathologies involving the aortic arch.The short-and mid-term results of this technique are satisfactory;however,endoleak remains a major concern.Thus,here we designed a new chimney stent-graft to decrease the endoleak rate.Aim:To testify the feasibility and safety of the new chimney stent-graft system in a canine model.Material and methods:Six Labrador retrievers were used.Pre-operative data were collected and all operations were performed under general anesthesia.The main and chimney stent-grafts were implanted through the abdominal aorta and left subclavian artery approaches,respectively.Completion digital subtraction angiography(DSA)was performed to confirm the immediate outcomes.All dogs were fed separately for 6 months and sacrificed after aortic angiography.The thoracic aorta and the main and chimney stent-grafts were harvested for histopathologic examination.Results:No complications were found in follow-up DSA.All branch arteries were patent.In?ammatory responses were observed around the stent-grafts in 3 experimental animals,and slight hyperplasia was observed in the surrounding tissues compared with the normal vessels.There was no mural thrombus in the stent,endothelial cells were noted on the inner surface of the stent,and thrombus was formed in the outer skirt and gutter area.The histopathologic examinations revealed similar results to those of gross necropsy observations.Conclusions:This study demonstrated the feasibility and safety of the Longuette stent-graft and the first to report a revised stent-graft specific for chimney technique.展开更多
The natural convective heat transfer performance of an aluminum hexagonal honeycomb acting as a novel heat sink for LED cooling is experi- mentally investigated. The concept of adding an adiabatic square chimney ex- t...The natural convective heat transfer performance of an aluminum hexagonal honeycomb acting as a novel heat sink for LED cooling is experi- mentally investigated. The concept of adding an adiabatic square chimney ex- tension for heat transfer enhancement is proposed, and the effects of chimney shape, height, and diameter are quantified. The average Nuav of a heated hon- eycomb with straight chimney is significantly higher than that without chimney, and the enhancement increases with increasing chimney height. At a given chim- ney height, honeycombs with divergent chimneys perform better than those with convergent ones. For a fixed divergent angle, the Nuav number increases mono- tonically with increasing chimney height. In contrast, with the convergent angle fixed, there exists an optimal chimney height to achieve maximum heat transfer.展开更多
The determination of the stable isotopes, δD, δ18 and δ30, values from hydrothermal chimneys in the Mariana Trough, the West Pacific, indicated that the pure siliceous chimneys with gentle data variation were forme...The determination of the stable isotopes, δD, δ18 and δ30, values from hydrothermal chimneys in the Mariana Trough, the West Pacific, indicated that the pure siliceous chimneys with gentle data variation were formed in low temperature environment. It reflects that the sea-floor hydrothermal activity of the Mariana Trough is primarily low-to-medium temperature hydrothermal eruption, and those chimneys with strong data variation and containing pyrite were formed in higher temperature environment. Key words Mariana Trough - stable isotope - geochemistry - hydrothermal chimney - genetic type Project 49876016 supported by NSFC.展开更多
The uniform design method was adopted and the twenty-four groups of different geometric and physical pa-rameters were chosen. The finite element model was built. Comparisons between the simulation results and the test...The uniform design method was adopted and the twenty-four groups of different geometric and physical pa-rameters were chosen. The finite element model was built. Comparisons between the simulation results and the test re-sults prove that the simulation results are correct. The distribution of the temperature field of the chimney foundationwas analyzed. The multivariate linear regression of the hightest tomperature was performed on the inner wall of thechimney foundation by the numerical calculated results. The fitting property of the highest temperature with six influ-ence factors was obtained. A simple method for the calculation of the temperature field of the chimney foundation wasprovided.展开更多
High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9oN–10oN. Sr isotopes show these anhydrites are precipitated from a mi...High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9oN–10oN. Sr isotopes show these anhydrites are precipitated from a mixture between hydrothermal fluid and seawater. The calculated relative proportion of seawater and hydrothermal fluid shows that the mixing is heterogeneous on the transection of the L vent chimney. Anhydrites from the chimney show uniform chondrite-normalized REE pattern with enrichment of LREE and positive Eu anomaly. While normalized to the REE of end-member hydrothermal fluid, anhydrites also show uniform REE pattern but with negative Eu anomaly and enrichment of HREE. Combining previous studies on REEs of hydrothermal fluids from different hydrothermal systems and the hydrothermal fluid data from this region, we suggested that REE-anion complexing, rather than crystallography controlling, is the main factor that controls the REE partition behavior in the anhydrite during its precipitation from the mixture of hydrothermal fluid and seawater.展开更多
A roof solar chimney (RSC) is inclined in the roof of a building wherein solar radiation is employed to heat the air the channel. The hot air flows up the channel which can be used to induce flow out of the building i...A roof solar chimney (RSC) is inclined in the roof of a building wherein solar radiation is employed to heat the air the channel. The hot air flows up the channel which can be used to induce flow out of the building in order to ventilate it. In this study, parameters that affect the performance of this natural ventilation system were investigated numerically, namely: inclination angles, channel gaps, solar intensities, vertical chimney attachment heights and channel expanding angles. The two last parameters were new concepts that seem to have never been studied before. All of the mentioned parameters were found to exhibit positive effects on the ventilation. Relative merits of these techniques were compared and discussed.展开更多
Solar collector is a thermal device that uses the heated air in the power generation and many engineering applications. The purpose of the present work is to study the performance and temperature distribution for the ...Solar collector is a thermal device that uses the heated air in the power generation and many engineering applications. The purpose of the present work is to study the performance and temperature distribution for the solar collector which uses heated air in solar chimney power generation that it consist of three parts, a turbine-generator unit which is used in the generation of electric energy, and cylindrical chimney is fixed vertically and finally a solar collector under the climatic conditions of Egypt-Aswan is studied. This site is specified as the hottest site because the nearest of this location from the Tropic of cancer. Experiments are performed in ten summer days of May and June 2015 with different solar radiations and clarity of the sky. Hourly values of global solar radiation and some meteorological data (temperature, pressure, velocity, etc.) for measuring days are obtained by measuring devices. Inlet and outlet temperatures of air from a solar collector and velocity at junction region. In this work, attempt has been made to present the effect of environmental factors such as ambient temperature, the clarity of the sky and solar radiation on the performance of solar collector. The temperature of the base and the cover of the solar collector, the variation of solar radiation, solar collector efficiency, heat transfer coefficient, the velocity at the junction region between the chimney base, the outlet of the solar collector and temperature distribution along the air heater are discussed. A prediction for the results of the solar collector were performed by using developed theoretical model was made by this study which is based on the previous works. The numerical study has used a commercial code CFX, ANSYS 16.1 to simulate the flow through the collector. The study show that the outlet air temperatures from the solar collector and the velocity at the junction are depending on the climate condition such as ambient temperature and solar radiation, the differences in air temperature at the solar collector ranging between 8° - 24°. It is concluded that the theoretical model is basically valid for the system under study, and theCFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.展开更多
The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three par...The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three parts, the solar collector, the chimney and the turbine generator unit, of which the study was focused on the later part. To evaluate the turbine performance inside the solar chimney powerplant, experimental system was constructed in Aswan, Egypt that has a metrological site (23°58'N and 32°47'E) occurs. The system was constructed to evaluate the performance of the solar chimney turbine and power generation characteristic in the hottest site where Aswan is located at the nearest of the Tropic of Cancer at the summer season. Velocity, electric power generation and the turbine efficiency are studying in this work. The numerical analyses were performed by using a commercial code CFX, ANSYS 16.1 to simulate the flow through the turbine and overall system. The study shows that the range of power generated (1.2 W - 4.4 W). It can be estimated, according to the results, the variation trend in pressure drops with the turbine rotation speed increase with small differences when the turbine rotation speed surpasses 1800 rpm with average efficiency of 57%. It is concluded that the theoretical model is basically valid for the system under study, and the CFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.展开更多
The mathematic model of heat transfer through ventilated double glazing was verified with the measured data,which were from a test chamber equipped with glass face temperature,solar radiation,ambient temperature,and w...The mathematic model of heat transfer through ventilated double glazing was verified with the measured data,which were from a test chamber equipped with glass face temperature,solar radiation,ambient temperature,and wind speed measurement facility.After the model validation,the double-skin facade assessment was carried out through simulation with ESP-r software integrating thermal simulation and air low net work module.The air flow situation in the air gap was analyzed on the basis of the hourly air velocity simulation data within typical winter week,summer week,spring week and autumn week.The differences of chimney effect in different seasons were discussed,and the thermal loads resulted from the ventilated and unventilated double skin facade were presented.展开更多
Hydrothermal fuid containing abundant matter erupts from seafloor, meets ambient cold seawater and forms chimneys. So the main matter origins of chimneys are seawater and matter which are taken by hydrothermal fluid f...Hydrothermal fuid containing abundant matter erupts from seafloor, meets ambient cold seawater and forms chimneys. So the main matter origins of chimneys are seawater and matter which are taken by hydrothermal fluid from deep reservoir. However, because of seawater＇s little contribution to the forming of chimneys, it is usually covered by the abundant matter which is taken by hydrothermal fluid. Therefore, chimneys formed in ordinary deep elements, cannot be used to study the seawater＇s seawater hydrothermal activity, containing complex contribution to their formation. While the native sulfur chimneys, formed by hydrothermal activity near the sea area off Kueishantao, are single sulfur composition （over 99%）, and within chimneys distinct layers are seen. Different layers were sampled for trace element determination, with Inductively Coupled Plasma Mass Spectrometry （ICP-MS）. By analyzing the data, we consider C-layer （secondary inner-layer） as the framework layer of the chimney which formed early （Fig.4）, and its trace elements derive from hydrothermal fluid. While the trace elements within A, B, D layers have undergone later alteration. A, B layers are affected by seawater and D layer by hydrothermal fluid. The increase of trace elements of A and B layers was calculated using C layer as background. Based on the known typical volume of chimneys of the near sea area off Kueishantao, we calculated the volume of seawater that contributed trace element to chimneys formation to be about 6.37×10^4 L. This simple quantified estimate may help us better understand the seafloor hydrothermal activity and chimneys.展开更多
Flue gases exhausted from thermal power plants contain more than 50% of the fuel thermal energy. In the present work, experimental investigation was carried out to study the utilization of thermal energy in flue gases...Flue gases exhausted from thermal power plants contain more than 50% of the fuel thermal energy. In the present work, experimental investigation was carried out to study the utilization of thermal energy in flue gases to enhance the performance of modified solar chimney consisting of Savonius wind rotor. A modified solar chimney model was designed and fabricated to carry out experimental measurement. The model consists of thermal energy conversion unit; Savonius wind rotor and a chimney. The thermal energy in the flue gas transfers to the air particles in the air channel across the absorber plate and results in upward air stream due to the buoyancy effect. With an 9 absorber area of 2.36 re＇and flue gas mass flow rate of0.18 kg/s, air velocity＇ of 4.1 m/s was achieved at the top of the thermal unit. Increasing the mass flow rate of the flue gas to 0.24 kg/s enhances the air velocity to be 4.6 m/s. The results have demonstrated the possibility＇ of utilizing the thermal energy in the waste flue gas to enhance the performance of a solar chimney and facilitate the continuous operation during the absence of the sun.展开更多
In this paper, according to the data from several single nuclear explosion experiments of an equivalent to magnitude of million tons, and combined with meteorological data, their effects on the regional climate nave b...In this paper, according to the data from several single nuclear explosion experiments of an equivalent to magnitude of million tons, and combined with meteorological data, their effects on the regional climate nave been analysed.展开更多
基金supported by the Guangzhou Marine Geological Survey,China Geological Survey,Guangzhou,China(No.2022C-24-216)financed by the General Project of the Shandong Natural Science Foundation,China(No.ZR2020ME090).
文摘The Shenhu Area in the South China Sea is rich in oil and gas resources and has many vertical gas chimneys,making it an excellent geological environment for hydrate accumulation.This paper examines the geological conditions governing these gas-chimneys.A numerical simulation method based on the partial-equilibrium reaction model of hydrate was applied to simulate the migration of methane gas and the resultant hydrate formation when the gas enters the hydrate stability zone under the seabed through gas-chimneys.The dynamics of this gaschimney hydrate accumulation were analyzed,and the influences of different factors―namely,the fluid supply time,rate,and temperature―on the formation temperature and ultimate distribution of the hydrate reservoir were evaluated.The simulation results indicate that the accumulation of hydrate via gas-chimneys is significantly affected by the temperature of the gas source,the transfer state of the methane gas,and the number of cycles of alternating gas-water invasion.Hydrate accumulation takes shape in an annular or semi-annular distribution pattern divided by fluid state as follows:a two-phase gas-water zone,a three-phase gas-water-hydrate zone,a two-phase water-hydrate zone,and a phase of water passing from the inside to the outside.Formation inclination and reservoir heterogeneity can greatly affect the distribution shape and abundance of the hydrate.A high fluid supply temperature,frequent alternating invasions of gas and water,and long-term pore-water invasion at a high rate can jointly cause a large central hydrate-free zone.In contrast,a long-term supply shutdown during the alternating gas-water invasion process,and a high gas rate with a low water rate in the gas-dominant invasion stage,foster the accumulation of hydrate in great abundance and with considerable thickness.The results of this study can help us understand the accumulation of hydrate through gas chimneys in the Shenhu Area.
文摘Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.
基金supported by the National Natural Science Foundation of China(Nos.92055211,42249801)the China-ASEAN Maritime Cooperation Fund Project(No.12120100500017001)。
文摘Gas chimneys,salt domes,and faults are vital to the movement of hydrocarbons within geological systems.Accurate identification of these geological features is crucial to modeling hydrocarbon resources.This study explores the processes that have shaped the eastern Persian Gulf,focusing on salt diapir characteristics,origin,and fluid migration.Plate collisions between the Indian,Eurasian,and Arabian Plates have considerably impacted salt tectonics,developing key features such as the Hormuz salt,Qatar-South Fars Arch,and Zagros and Oman orogenic structures.Salt-related features were discerned through two-dimensional seismic data and drilling records,salt movement sequences were reconstructed,and fluid expulsion patterns were delineated using attribute preferences.The results of this study revealed that fractured substrates influenced by regional tectonic forces contribute to the creation of salt diapirs,which serve as conduits for guided fluid transport.Moreover,these results showed that gravity-driven downbuilding mainly controls salt flow,while the circular arrangement of salt structures results from regional stress and interactions between different salt sources.Distinct stress-induced basement incisions compounded by the hindrance of initial salt movement by the Qatar Arch further contribute to the complex salt structure geometry.Crucially,the uplift of the Qatar Arch and stresses from the Oman and Zagros orogenies profoundly affect the salt structure geometry and depositional patterns across diverse regions,resulting in circular salt structures and gas chimneys.This study offers valuable perspectives for oil and gas exploration and provides a comprehensive understanding of the regional dynamics governing salt tectonics and hydrocarbon ascent in the eastern Persian Gulf.
文摘目的:总结Chimney支架技术联合All in One技术在经导管主动脉瓣置换术(TAVR)中应用的初步经验。方法:收集2021年7月至2022年7月首都医科大学附属北京安贞医院心脏瓣膜病介入中心在TAVR术中联合应用Chimney支架技术和All in One技术的10例患者进行回顾性分析,总结临床资料、影像学资料、手术操作、住院和出院随访期间主要不良心脑血管事件的发生情况。结果:10例患者中男性4例,女性6例,平均年龄(76.2±3.9)岁,三叶式主动脉瓣7例,二叶式主动脉瓣3例,术前CT评估均有冠状动脉阻塞危险因素,并且术中球囊预扩张提示冠状动脉阻塞。所有患者均使用一枚药物洗脱支架完成Chimney支架技术,冠状动脉支架置入有8例位于左主干,2例位于右冠状动脉,支架平均直径(3.7±0.3)mm,平均长度(20.6±2.4)mm,在住院及平均随访(7.8±3.7)个月期间,无死亡、心肌梗死、脑卒中等主要不良心脑血管事件发生。结论:TAVR术中Chimney支架技术联合All in One技术安全可行。
文摘An extinct hydrothermal barite-silica chimney from the Franklin Seamount of the Woodlark Basin, in the southwestern Pacific Ocean, was investigated for mineral distribution and geochemical composition. Six layers on either side of the orifice of a chimney show significant disparity in color, mineral assemblage and major element composition. Electron microscope（SEM） images reveal that the peripheral wall of the chimney is composed of colloform silica, suggesting that incipient precipitation of silica-saturated hydrothermal fluid initiated the development of the chimney wall. Intermediate layers, between the exterior wall and the inner fluid-orifice, dominate with barite and sulfides. Low Sr-to-Ba ratios（SrO/BaO = 0.015–0.017） indicate restricted fluid-seawater mixing, which causes relatively high-temperature formation of the intermediate layers. Whereas the innermost layer bordering the chimney orifice is characterized by more silica and a higher Sr-to-Ba ratio（SrO/BaO = 0.023）, could have formed due to a paragenetic shift from a high-temperature active phase to a cooler waning stage of formation. A paragenetic shift is also probably responsible for the change in mineral formation mechanism that resulted in the textural variation of barite and colloform silica developed during different growth phases of this barite-silica chimney.
基金This study was supported by the National Natural Science Foundation of China under the contract No.40276024 and 49873015.
文摘Hydrothermal chimney is a product of hydrothermal activity on the seabed. Chimney samples dredged from Jade hydrothermal area in Izena depression of the Okinawa Trough, are characterized by relatively enriched light rare earth elements (LREE) and strongly positive Eu anomalies. 87Sr/86Sr and 143Nd/144Nd of these samples are exactly between those of seawater and of acidic pumice, averaged at 0.708928 and 0.512292, respectively. These characteristics imply that the main source of hydrothermal sulfide at Jade area is possibly the undersurface acidic rocks. The mineralizing mechanism can be summarized as follows: Large amount of mineralized material would be leached out and LREE-enriched hydrothermal solution would be subsequently produced as a result of thermo-chemical exchange reaction between acidic volcanic rocks and heated seawater that penetrated in advance from upper water mass. The spurting out from the seabed and quickly crystallizing in the seawater of hydrothermal solution are responsible for the formation of Cu-Zn sulfide and barite-amorphous SiO2 minerals that are characterized by enriched LREE and positively strong Eu anomalies.
文摘A sulfide black smoker chimney exists in the Gaobanhe seabed exhalation massive sulfide deposit in the Xingiong-Kuancheng secondary fault basin of the Proterozoic Yaniiao rift trough in Hebei Province, taking the shape of mounds, individually about 2-3 cm high. Abundant fossils of thermophilous bacteria and algae in perfect preservation are found in the ore surrounding the black smoker chimney. Scanning electron microscopy （SEM） and molecular biomarker studies on the microorganismai ore fabric show that the microorganism in the sulfide ore is in fact a sedimentary product of probiotic bacteria and algae. In the special food chain based on black smoker chimney at ancient seabed- thermophilous bacteria, the thermophilous bacteria and algae reproduce in large quantity. Intermittently erupting of fluid from the chimney creats conditions for formation of sulfide deposit. In the process of exhalation action of hot fluid, thermophilous bacteria and algae grow and reproduce around the sulfide black smoker chimney, absorbing mineralizing substances brought by the fluid. Massive sulfide deposits are formed in this process of absorption of seabed black smoker chimney exhalation-mineralizing fluid pulsation-thermophilous microorganism.
文摘Introduction:Parallel stent-stent grafting is a major endovascular technique used to preserve the supra-aortic branches during thoracic endovascular aortic repair(TEVAR)of aortic pathologies involving the aortic arch.The short-and mid-term results of this technique are satisfactory;however,endoleak remains a major concern.Thus,here we designed a new chimney stent-graft to decrease the endoleak rate.Aim:To testify the feasibility and safety of the new chimney stent-graft system in a canine model.Material and methods:Six Labrador retrievers were used.Pre-operative data were collected and all operations were performed under general anesthesia.The main and chimney stent-grafts were implanted through the abdominal aorta and left subclavian artery approaches,respectively.Completion digital subtraction angiography(DSA)was performed to confirm the immediate outcomes.All dogs were fed separately for 6 months and sacrificed after aortic angiography.The thoracic aorta and the main and chimney stent-grafts were harvested for histopathologic examination.Results:No complications were found in follow-up DSA.All branch arteries were patent.In?ammatory responses were observed around the stent-grafts in 3 experimental animals,and slight hyperplasia was observed in the surrounding tissues compared with the normal vessels.There was no mural thrombus in the stent,endothelial cells were noted on the inner surface of the stent,and thrombus was formed in the outer skirt and gutter area.The histopathologic examinations revealed similar results to those of gross necropsy observations.Conclusions:This study demonstrated the feasibility and safety of the Longuette stent-graft and the first to report a revised stent-graft specific for chimney technique.
基金supported by the National 111 Project of China(B06024)the National Basic Research Program of China(2011CB610305)the National Natural Science Foundation of China(51206128)
文摘The natural convective heat transfer performance of an aluminum hexagonal honeycomb acting as a novel heat sink for LED cooling is experi- mentally investigated. The concept of adding an adiabatic square chimney ex- tension for heat transfer enhancement is proposed, and the effects of chimney shape, height, and diameter are quantified. The average Nuav of a heated hon- eycomb with straight chimney is significantly higher than that without chimney, and the enhancement increases with increasing chimney height. At a given chim- ney height, honeycombs with divergent chimneys perform better than those with convergent ones. For a fixed divergent angle, the Nuav number increases mono- tonically with increasing chimney height. In contrast, with the convergent angle fixed, there exists an optimal chimney height to achieve maximum heat transfer.
文摘The determination of the stable isotopes, δD, δ18 and δ30, values from hydrothermal chimneys in the Mariana Trough, the West Pacific, indicated that the pure siliceous chimneys with gentle data variation were formed in low temperature environment. It reflects that the sea-floor hydrothermal activity of the Mariana Trough is primarily low-to-medium temperature hydrothermal eruption, and those chimneys with strong data variation and containing pyrite were formed in higher temperature environment. Key words Mariana Trough - stable isotope - geochemistry - hydrothermal chimney - genetic type Project 49876016 supported by NSFC.
文摘The uniform design method was adopted and the twenty-four groups of different geometric and physical pa-rameters were chosen. The finite element model was built. Comparisons between the simulation results and the test re-sults prove that the simulation results are correct. The distribution of the temperature field of the chimney foundationwas analyzed. The multivariate linear regression of the hightest tomperature was performed on the inner wall of thechimney foundation by the numerical calculated results. The fitting property of the highest temperature with six influ-ence factors was obtained. A simple method for the calculation of the temperature field of the chimney foundation wasprovided.
基金supported by the China Ocean Mineral Resource R & D Association (COMRA) Projects (Nos. DY125-13-R-08, DY125-13-R-01, and DY125-13-R-05)
文摘High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9oN–10oN. Sr isotopes show these anhydrites are precipitated from a mixture between hydrothermal fluid and seawater. The calculated relative proportion of seawater and hydrothermal fluid shows that the mixing is heterogeneous on the transection of the L vent chimney. Anhydrites from the chimney show uniform chondrite-normalized REE pattern with enrichment of LREE and positive Eu anomaly. While normalized to the REE of end-member hydrothermal fluid, anhydrites also show uniform REE pattern but with negative Eu anomaly and enrichment of HREE. Combining previous studies on REEs of hydrothermal fluids from different hydrothermal systems and the hydrothermal fluid data from this region, we suggested that REE-anion complexing, rather than crystallography controlling, is the main factor that controls the REE partition behavior in the anhydrite during its precipitation from the mixture of hydrothermal fluid and seawater.
文摘A roof solar chimney (RSC) is inclined in the roof of a building wherein solar radiation is employed to heat the air the channel. The hot air flows up the channel which can be used to induce flow out of the building in order to ventilate it. In this study, parameters that affect the performance of this natural ventilation system were investigated numerically, namely: inclination angles, channel gaps, solar intensities, vertical chimney attachment heights and channel expanding angles. The two last parameters were new concepts that seem to have never been studied before. All of the mentioned parameters were found to exhibit positive effects on the ventilation. Relative merits of these techniques were compared and discussed.
文摘Solar collector is a thermal device that uses the heated air in the power generation and many engineering applications. The purpose of the present work is to study the performance and temperature distribution for the solar collector which uses heated air in solar chimney power generation that it consist of three parts, a turbine-generator unit which is used in the generation of electric energy, and cylindrical chimney is fixed vertically and finally a solar collector under the climatic conditions of Egypt-Aswan is studied. This site is specified as the hottest site because the nearest of this location from the Tropic of cancer. Experiments are performed in ten summer days of May and June 2015 with different solar radiations and clarity of the sky. Hourly values of global solar radiation and some meteorological data (temperature, pressure, velocity, etc.) for measuring days are obtained by measuring devices. Inlet and outlet temperatures of air from a solar collector and velocity at junction region. In this work, attempt has been made to present the effect of environmental factors such as ambient temperature, the clarity of the sky and solar radiation on the performance of solar collector. The temperature of the base and the cover of the solar collector, the variation of solar radiation, solar collector efficiency, heat transfer coefficient, the velocity at the junction region between the chimney base, the outlet of the solar collector and temperature distribution along the air heater are discussed. A prediction for the results of the solar collector were performed by using developed theoretical model was made by this study which is based on the previous works. The numerical study has used a commercial code CFX, ANSYS 16.1 to simulate the flow through the collector. The study show that the outlet air temperatures from the solar collector and the velocity at the junction are depending on the climate condition such as ambient temperature and solar radiation, the differences in air temperature at the solar collector ranging between 8° - 24°. It is concluded that the theoretical model is basically valid for the system under study, and theCFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.
文摘The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three parts, the solar collector, the chimney and the turbine generator unit, of which the study was focused on the later part. To evaluate the turbine performance inside the solar chimney powerplant, experimental system was constructed in Aswan, Egypt that has a metrological site (23°58'N and 32°47'E) occurs. The system was constructed to evaluate the performance of the solar chimney turbine and power generation characteristic in the hottest site where Aswan is located at the nearest of the Tropic of Cancer at the summer season. Velocity, electric power generation and the turbine efficiency are studying in this work. The numerical analyses were performed by using a commercial code CFX, ANSYS 16.1 to simulate the flow through the turbine and overall system. The study shows that the range of power generated (1.2 W - 4.4 W). It can be estimated, according to the results, the variation trend in pressure drops with the turbine rotation speed increase with small differences when the turbine rotation speed surpasses 1800 rpm with average efficiency of 57%. It is concluded that the theoretical model is basically valid for the system under study, and the CFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.
基金Supported by Shanghai Science and Technology Supporting Program(08DZ1203500)City University of Hong Kong(7002004)+1 种基金Shanghai Local University Fund(071605124)Undergraduates Education Fund for University of Shanghai
文摘The mathematic model of heat transfer through ventilated double glazing was verified with the measured data,which were from a test chamber equipped with glass face temperature,solar radiation,ambient temperature,and wind speed measurement facility.After the model validation,the double-skin facade assessment was carried out through simulation with ESP-r software integrating thermal simulation and air low net work module.The air flow situation in the air gap was analyzed on the basis of the hourly air velocity simulation data within typical winter week,summer week,spring week and autumn week.The differences of chimney effect in different seasons were discussed,and the thermal loads resulted from the ventilated and unventilated double skin facade were presented.
基金Supported by the Pilot Project of Knowledge Innovation Project, Chinese Academy of Sciences (No.KZCX2-YW-211and KZCX3-SW- 223)the National Natural Science Foundation of China (No. 40830849)the Special Foundation for the Eleventh Five-Year Plan of COMRA (No. DYXM-115-02-1-03).
文摘Hydrothermal fuid containing abundant matter erupts from seafloor, meets ambient cold seawater and forms chimneys. So the main matter origins of chimneys are seawater and matter which are taken by hydrothermal fluid from deep reservoir. However, because of seawater＇s little contribution to the forming of chimneys, it is usually covered by the abundant matter which is taken by hydrothermal fluid. Therefore, chimneys formed in ordinary deep elements, cannot be used to study the seawater＇s seawater hydrothermal activity, containing complex contribution to their formation. While the native sulfur chimneys, formed by hydrothermal activity near the sea area off Kueishantao, are single sulfur composition （over 99%）, and within chimneys distinct layers are seen. Different layers were sampled for trace element determination, with Inductively Coupled Plasma Mass Spectrometry （ICP-MS）. By analyzing the data, we consider C-layer （secondary inner-layer） as the framework layer of the chimney which formed early （Fig.4）, and its trace elements derive from hydrothermal fluid. While the trace elements within A, B, D layers have undergone later alteration. A, B layers are affected by seawater and D layer by hydrothermal fluid. The increase of trace elements of A and B layers was calculated using C layer as background. Based on the known typical volume of chimneys of the near sea area off Kueishantao, we calculated the volume of seawater that contributed trace element to chimneys formation to be about 6.37×10^4 L. This simple quantified estimate may help us better understand the seafloor hydrothermal activity and chimneys.
文摘Flue gases exhausted from thermal power plants contain more than 50% of the fuel thermal energy. In the present work, experimental investigation was carried out to study the utilization of thermal energy in flue gases to enhance the performance of modified solar chimney consisting of Savonius wind rotor. A modified solar chimney model was designed and fabricated to carry out experimental measurement. The model consists of thermal energy conversion unit; Savonius wind rotor and a chimney. The thermal energy in the flue gas transfers to the air particles in the air channel across the absorber plate and results in upward air stream due to the buoyancy effect. With an 9 absorber area of 2.36 re＇and flue gas mass flow rate of0.18 kg/s, air velocity＇ of 4.1 m/s was achieved at the top of the thermal unit. Increasing the mass flow rate of the flue gas to 0.24 kg/s enhances the air velocity to be 4.6 m/s. The results have demonstrated the possibility＇ of utilizing the thermal energy in the waste flue gas to enhance the performance of a solar chimney and facilitate the continuous operation during the absence of the sun.
文摘In this paper, according to the data from several single nuclear explosion experiments of an equivalent to magnitude of million tons, and combined with meteorological data, their effects on the regional climate nave been analysed.
