Deep-large faults controlling on the distribution of the venting gas hydrate system in the middle of the Qiongdongnan Basin, South China Sea

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.

A CFD study on optimal venting volume and air flow distribution in a special designed hood system for controlling dust flow

A novel hood structure has been designed for the dust control system in the foundry in order to improve the working environment. A composite strategy has been applied for comparative analysis of the optimal venting volume and the airflow distribution between the conventional hood and the novel one in this study. A Computational Fluid Dynamic (CFD) method is used to simulate the airflow fields and dust-polluted air moving paths. The CFD results show that a two-outlet hood, with one outlet located on the left of the hood, is better for improving dust-polluted air than the hood with one outlet only. It can be concluded that the number of the outlets as well as their location on the hood has a significant influence on the air flow pattern in the hood. The optimal venting volume is also a major consideration that is discussed in the study. The venting volume should be designed by considering both the effective level of air flow velocity around the dust source and the energy saving. The optimal airflow distribution may reduce the turbulence in the hood system.

Effect of safety valve types on the gas venting behavior and thermal runaway hazard severity of large-format prismatic lithium iron phosphate batteries

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.

Characteristic of Intelligent Air Bag Venting Structure Actuating by Electrostrictive Stack Actuator

In this paper the conception of smart materials and structures is firstly combined with research of air bag,and the main theory of self adapting cushioning of intelligent air bag is expatiated.The intelligent venting structure is the main part affecting the cushioning result.Electrostrictive material was found having big force,high response speed and wide linearity,and it is fit to utilize in intelligent venting structure. The characteristic of the dynamic response and cushioning actuating of an electrostrictive stack actuator is analyzed,and the result of the computer simulation of the fuzzy control to intelligent venting structure is given.It is concluded that intelligent venting structure has good actuating characteristic and can satisfy the need of intelligent air bag.

Venting Design for Di-tert-butyl Peroxide Runaway Reaction Based on Accelerating Rate Calorimeter Test

In order to design the relief system size of di-tert-butyl peroxide(DTBP) storage tanks,the runaway re-action of DTBP was simulated by accelerating rate calorimeter(ARC).The results indicated that under adiabatic conditions the initial exothermic temperature was 102.6 ℃,the maximum self-heating rate was 3.095×107 ℃·min-1,the maximum self-heating temperature was 375.9 ℃,and the pressure produced by unit mass was 4.512 MPa·g-1.Judged by ARC test,the emergency relief system for DTBP was a hybrid system.Based on Design Institute for Emergency Relief System(DIERS) method,the releasing mass flow rate W was determined by Leung methods,and the mass velocity G was calculated by two modified Omega methods.The two relief sizes calculated by monograph Omega method and arithmetic Omega method are close,with only 0.63% relative error.The monograph Omega method is more convenient to apply.

Multi-objective Optimization Design of Vented Cylindrical Airbag Cushioning System for Unmanned Aerial Vehicle

Multi-objective optimization design of the gas-filled bag cushion landing system is investigated.Firstly,the landing process of airbag is decomposed into a adiabatic compression and a release of landing shock energy,and the differential equation of cylindrical gas-filled bag is presented from a theoretical perspective based on the ideal gas state equation and dynamic equation.Then,the effects of exhaust areas and blasting pressure on buffer characteristics are studied,taking those parameters as design variable for the multiobjective optimization problem,and the solution can be determined by comparing Pareto set,which is gained by NSGA-Ⅱ.Finally,the feasibility of the design scheme is verified by experimental results of the ground test.

Experimental investigation of external explosion in the venting process

Experimental investigations were conducted on the process of combustion and explosion vent in a 200 mm (diame- ter)×400 mm (length) vertical cylindrical vessel. When CH4-air mixture gases were used and the vent diameter was 55 mm, conditions of Φ (equivalent ratio)=0.8, Φ=1.0 and Φ=1.3 and two ignition positions (at the cylinder center and bottom) were selected. The venting processes and the correlated factors are discussed in this paper.

Simulation on venting process and valve opening control method for gas trunk pipelines

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.

TURBULENCE, VORTEX AND EXTERNAL EXPLOSION INDUCED BY VENTING

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.

Eyes of diff ering colors in Alvinocaris longirostris from deep-sea chemosynthetic ecosystems: genetic and molecular evidence of its formation mechanism

Coloration is an important phenotypic trait for multiple adaptive functions.It is interesting to fi nd white-eye(AW)and orange-eye(AO)phenotypes in the shrimp Alvinocaris longirostris inhabiting the deep-sea cold seep and hydrothermal vent areas of the northwestern Pacifi c.By comparative transcriptome analyses,1491 diff erentially expressed genes(DEGs)were identified between AW and AO.Among them,many DEGs were associated with immunity,antioxidation,and detoxifi cation.Two signifi cant enzyme encoding genes,xanthine dehydrogenase,and tryptophan oxidase involved in pigment biosynthesis pathways were up-regulated in AW and AO,respectively,which might be related to the diff erences of white and orange eye phenotypes.Moreover,single nucleotide polymorphism(SNP)calling detected that genotypes of 28 SNP distributing in 14 unigenes were completely diff erent between AW and AO.Particularly,there were three and two non-synonymous mutations in immune genes crustin Pm5 and antimicrobial peptide,respectively.Results indicate that the diff erence in eye color is probably resulted from immune response to variable micro-environmental stressors encountered in the dispersal process of the shrimps,such as symbiotic microbes,pathogens,and toxic substances,and might be genetically fi xed at last.The suggested pathway preliminarily explained the formation mechanism of diff erent eye phenotypes in Alvinocaridid shrimps,providing a basis for further study on adaptive evolution of eyes in deep-sea chemosynthetic faunas.

Left Ventricular Pseudoaneurysm Caused by a Left Ventricular Venting Catheter via the Right Superior Pulmonary Vein during Thoracic Aortic Surgery: A Case Report

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.

Importance of LV Venting after ECMO Implantation in Post-Cardiotomy Syndrome: A Case Report

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.

Filtered Containment Venting： Reasons, Technology,Impact on Environment

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.

COUNTERACTING HIGH WINDS WITH LOW PRESSURE:DEVELOPMENT AND TESTING OF A NEW ROOF VENT SYSTEM

Roof system failures are common during high wind events.In locations subject to high wind conditions,membrane roofing systems must typically be either physically attached or fully adhered to the substrate or ballast may be added to weigh down the membrane.An alternative to these installation approaches could be to use aerodynamics principles such as the Bernoulli and Venturi effects to create a low-pressure region beneath the membrane roof that is lower than the ambient pressure and thus counteracts the uplifting force.A new omnidirectional vent has been designed and tested that takes advantage of these aerodynamics principles to induce low pressure under the membrane layer.This new vent operates with no moving parts and was tested in the high-speed stability wind tunnel at Virginia Tech to wind speeds up to 233 km/h.The results demonstrate that this new vent generates pressures lower than the ambient when subjected to high wind conditions.This paper presents the design principles and performance test results for this new roof vent system and other applications for roof vent technologies.

VELA■呼吸机常见两例故障分析及排除

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。

雄构树花序化学成分研究

目的 :研究雄构树Broussonetiapapyrifera(L )Vent花序的化学成分。方法 :利用硅胶柱色谱分离纯化 ,根据化合物的光谱数据进行结构鉴定。结果 :从雄构树花序中得到 4个化合物 ,鉴定分别为 5 甲基 3 十四烷基戊内酯 (5 methyl 3 tetradecyl 5 pentandide,Ⅰ )、二十四碳烷醇 (Tetracosanol,Ⅱ )、尿嘧啶 (uracil,Ⅲ )、正十六碳酸 (hexadecylicacid ,Ⅳ )。结论 :化合物Ⅰ～Ⅳ为首次从该植物中分离得到。

野生植物构树的生物学、生态学及园林应用

构树[Broussonetia papyrifera(L.)Vent.]的自然更新机制完善、适应性强、分布广泛,具有观赏价值和生态效益,是城市园林绿化的潜在树种资源。对野生植物构树的主要生物学、生态学特征及其在园林上的应用进行了综述。

杂交构树茎段组织培养体系的建立

以杂交构树[Broussonetia papyrifera (L.) Vent.]——中科一号为试验材料,通过对杂交构树茎段的离体培养和扩繁,探究了不同激素配比对杂交构树诱导愈伤、丛生芽、壮苗和生根的影响。试验结果表明,以具腋芽的构树茎段为外植体材料,75%乙醇溶液浸泡40 s后,再经0.3%HgCl2灭菌15 min,外植体的成活率可达44%;诱导愈伤组织的最佳培养基为MS+IBA 0.5 mg/L+6-BA 2.0 mg/L+蔗糖25 g/L+琼脂7.0 g/L,pH 5.6～5.8,愈伤诱导率达90%;诱导丛生芽的最佳培养基为MS+IBA 1.5 mg/L+6-BA2.0 mg/L+蔗糖25 g/L+琼脂7.0 g/L,pH 5.6～5.8,丛生芽增殖系数为4.2,生长势较好;壮苗的最佳培养基为MS+IBA 0.2 mg/L+6-BA 1.5 mg/L+蔗糖25 g/L+琼脂7.0 g/L,pH 5.6～5.8,平均株高4.8 cm;生根的最佳培养基为1/2 MS+IBA 0.8 mg/L+活性炭1.5 g/L+马铃薯50 g/L+蔗糖25 g/L+琼脂7.0 g/L,pH 5.6～5.8,生根率100%。最佳的炼苗移栽基质土为珍珠岩∶蛭石∶草炭=1∶1∶1的混合基质,幼苗生长得最好,平均株高为7.3 cm。

不同轮作模式对两种食用菌产量和品质的影响

为改善竹荪单作产量逐年降低问题,以长裙竹荪[Dictyophora indusiata(Vent.Pers.)Fisch.]和羊肚菌(Morchella vulgaris)为材料,设计长裙竹荪单作、羊肚菌单作、长裙竹荪-羊肚菌轮作、长裙竹荪-圆白菜轮作、羊肚菌-辣椒轮作对比试验,连续3年测定单位面积长裙竹荪和羊肚菌产量和部分品质指标。结果表明,与单作相比,轮作能够一定程度上提高长裙竹荪和羊肚菌产量及品质,其中羊肚菌-长裙竹荪轮作下二者的综合表现最好。羊肚菌-长裙竹荪轮作中长裙竹荪产量、单位面积子实体平均产出数量、去盖单株鲜重在栽培第2年和第3年均较单作显著增加,菌盖鲜重、菌高、菌柄直径和伞裙长度均显著增大,灰分、粗蛋白、粗脂肪和粗纤维含量较单作也略有增加,但二者间差异不显著;在栽培第2年和第3年,羊肚菌-长裙竹荪轮作下羊肚菌产量、子实体平均单株鲜重、单位面积子实体平均产出数量均较单作显著增加,羊肚菌灰分、粗脂肪和粗纤维含量均较单作显著增高,羊肚菌伞裙长度和菌柄直径在栽植第3年也较单作有所增大,菌盖与菌柄比大幅提高。羊肚菌-长裙竹荪轮作下羊肚菌形态、质量均显著提升。

Supply of Dissolved Organic Carbon from the Cold Seeps-Hydrothermal System and Its Impact on the Deep-Sea Carbon Cycle:An Overview

Dissolved carbon(dissolved organic carbon and dissolved inorganic carbon)is the major component of the ocean carbon cycle,representing one of the largest carbon pools on Earth.Cold seeps and hydrothermal systems serve as the two main windows for the material and energy recycling exchange between the lithosphere and outer spheres(biosphere,hydrosphere and atmosphere).However,recent studies have found that the dynamic activities of fluids in these two extreme systems are a crucial source of‘new'carbon in the deep ocean.These carbon sources may become vital contributors to carbon and energy in marine ecosystems,which affect the global deep-sea carbon budget,and the marine ecosystems as well.In this review,we summarize the sources and formation mechanisms of dissolved carbon in the seep fluids from the cold seeps and hydrothermal vents,the contribution of methane oxidation to dissolved carbon,and the characteristics of the carbon isotope composition in the fluid.Furthermore,we analyze and discuss the influence of carbon discharged from seabed on the seawater carbon cycle by comparing and contrasting these two extreme environments.The research may assist in promoting a deeper understanding of the carbon cycle and material interaction in the ocean,particularly further carbon cycle research in the back-arc basin where cold seeps and hydrothermal vents commonly prevail.