Enhanced structural damage behavior of liquid-filled tank by reactive material projectile impact

A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles(RMPs) impacting liquid-filled tanks,and the corresponding hydrodynamic ram(HRAM) was studied in detail.PTFE/Al/W RMPs with steel-like and aluminum-like densities were prepared by a pressing/sintering process.The projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/s.The corresponding cavity evolution characteristics and HRAM pressure were recorded by high-speed camera and pressure acquisition system,and further compared to those of steel and aluminum projectiles.Significantly different from the conical cavity formed by the inert metal projectile,the cavity formed by the RMP appeared as an ellipsoid with a conical front.The RMPs were demonstrated to enhance the radial growth velocity of cavity,the global HRAM pressure amplitude and the front panel damage,indicating the enhanced HRAM and structural damage behavior.Furthermore,combining the impact-induced fragmentation and deflagration characteristics,the cavity evolution of RMPs under the combined effect of kinetic energy impact and chemical energy release was analyzed.The mechanism of enhanced HRAM pressure induced by the RMPs was further revealed based on the theoretical model of the initial impact wave and the impulse analysis.Finally,the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and analyzed.It was determined that the enhanced near-field impulse induced by the RMPs was the dominant reason for the enhanced structural damage behavior.

Explosion damage effects of aviation kerosene storage tank under strong ignition

In order to study the blast damage effects of aviation kerosene storage tanks,the out-field explosion experiments of 8 m3fixed-roof tanks were carried out.The fragments,shock wave and fireball thermal radiation of the tank in the presence of bottom oil,half oil and full oil,as well as empty tank,were investigated under internal explosion by various TNT charge contents(1.8 kg,3.5 kg and 6.2 kg).The results showed that the tank roof was the only fragment produced,and the damage forms could be divided into three types.The increase of TNT charge content and oil volume enlarged the deformation of the tank,while the hole ratio presented a trend of increase first and then decrease.The H_r,maxand V_(max)values positively increased as increasing the TNT charge content and oil volume(from empty to half oil),but decreased in full oil.The Pmaxvalues had a progressive increase with the increment of TNT charge content,but not the case with the increase in oil volumes.The development of fireball was divided into three stages:tank roof‘towed'flame,jet flow flame tumbling and rising,and jet flow flame extinguishing.The Dmaxand Hf,maxvalues both increased as increasing TNT charge content and oil volumes.The oscillation phenomenon of fireball temperature was observed in the cooling process.The average temperature of fireball surface was positively correlated with TNT charge content,and negatively correlated with oil volumes.

Numerical Simulation of the Seismic Response of a Horizontal Storage Tank Based on a SPH-FEM Coupling Method

A coupled numerical calculation method combining smooth particle hydrodynamics(SPH)and the finite element method(FEM)was implemented to investigate the seismic response of horizontal storage tanks.Anumericalmodel of a horizontal storage tank featuring a free liquid surface under seismic action was constructed using the SPH–FEM coupling method.The stored liquid was discretized using SPH particles,while the tank and supports were discretized using the FEM.The interaction between the stored liquid and the tank was simulated by using the meshless particle contact method.Then,the numerical simulation results were compared and analyzed against seismic simulation shaking table test data to validate the method.Subsequently,a series of numerical models,considering different liquid storage volumes and seismic effects,were constructed to obtain time history data of base shear and top center displacement,which revealed the seismic performance of horizontal storage tanks.Numerical simulation results and experimental data showed good agreement,with an error rate of less than 18.85%.And this conformity signifies the rationality of the SPH-FEM coupling method.The base shear and top center displacement values obtained by the coupled SPH-FEM method were only 53.3% to 69.1% of those calculated by the equivalent mass method employed in the current code.As the stored liquid volume increased,the seismic response of the horizontal storage tank exhibited a gradual upward trend,with the seismic response increasing from 73% to 388% for every 35% increase in stored liquid volume.The maximum von Mises stress of the tank and the supports remained below the steel yield strength during the earthquake.The coupled SPH-FEM method holds certain advantages in studying the seismic problems of tanks with complex structural forms,particularly due to the representation of the flow field distribution during earthquakes by involving reservoir fluid participation.

Numerical simulation of inlet placement on sewage characteristics in the rounded square aquaculture tank with single inlet

To improve the self-cleaning ability of aquaculture tank and the efficiency of circulating water,physical and numerical experiments were conducted on the influence of inlet structure on sewage discharge in a rounded square aquaculture tank with a single inlet.Based on the physical model of the tank,analysis of how inlet structure adjustment affects sewage discharge efficiency and flow field characteristics was conducted to provide suitable flow field conditions for sinkable solid particle discharge.In addition,an internal flow field simulation was conducted using the RNG k-εturbulence model in hydraulic drive mode.Then a solid-fluid multiphase model was created to investigate how the inlet structure affects sewage collection in the rounded square aquaculture tank with single inlet and outlet.The finding revealed that the impact of inlet structure is considerably affecting sewage collection.The conditions of C/B=0.07-0.11(the ratio of horizontal distance between the center of the inlet pipe and the tank wall(C)to length of the tank(B))andα=25°(αis the angle between the direction of the jet and the tangential direction of the arc angle)resulted in optimal sewage collection,which is similar to the flow field experiment in the rounded square aquaculture tank with single inlet and outlet.An excellent correlation was revealed between sewage collection and fluid circulation stability in the aquaculture tank.The present study provided a reference for design and optimization of circulating aquaculture tanks in aquaculture industry.

The prediction of projectile-target intersection for moving tank based on adaptive robust constraint-following control and interval uncertainty analysis

To improve the hit probability of tank at high speed,a prediction method of projectile-target intersection based on adaptive robust constraint-following control and interval uncertainty analysis is proposed.The method proposed provides a novel way to predict the impact point of projectile for moving tank.First,bidirectional stability constraints and stability constraint-following error are constructed using the Udwadia-Kalaba theory,and an adaptive robust constraint-following controller is designed considering uncertainties.Second,the exterior ballistic ordinary differential equation with uncertainties is integrated into the controller,and the pointing control of stability system is extended to the impact-point control of projectile.Third,based on the interval uncertainty analysis method combining Chebyshev polynomial expansion and affine arithmetic,a prediction method of projectile-target intersection is proposed.Finally,the co-simulation experiment is performed by establishing the multi-body system dynamic model of tank and mathematical model of control system.The results demonstrate that the prediction method of projectile-target intersection based on uncertainty analysis can effectively decrease the uncertainties of system,improve the prediction accuracy,and increase the hit probability.The adaptive robust constraint-following control can effectively restrain the uncertainties caused by road excitation and model error.

Modern Corrosion Mapping of Storage Tank Bottoms--Notable Advancements in Critical Zone Coverage,Inspection Efficiency and Data Integrity

Every day,an NDT(Non-Destructive Testing)report will govern key decisions and inform inspection strategies that could affect the flow of millions of dollars which ultimately affects local environments and potential risk to life.There is a direct correlation between report quality and equipment capability.The more able the equipment is-in terms of efficient data gathering,signal to noise ratio,positioning,and coverage-the more actionable the report is.This results in optimal maintenance and repair strategies providing the report is clear and well presented.Furthermore,when considering tank floor storage inspection it is essential that asset owners have total confidence in inspection findings and the ensuing reports.Tank floor inspection equipment must not only be efficient and highly capable,but data sets should be traceable and integrity maintained throughout.Corrosion mapping of large surface areas such as storage tank bottoms is an inherently arduous and time-consuming process.MFL(magnetic flux leakage)based tank bottom scanners present a well-established and highly rated method for inspection.There are many benefits of using modern MFL technology to generate actionable reports.Chief among these includes efficiency of coverage while gaining valuable information regarding defect location,severity,surface origin and the extent of coverage.More recent advancements in modern MFL tank bottom scanners afford the ability to scan and record data sets at areas of the tank bottom which were previously classed as dead zones or areas not scanned due to physical restraints.An example of this includes scanning the CZ(critical zone)which is the area close to the annular to shell junction weld.Inclusion of these additional dead zones increases overall inspection coverage,quality and traceability.Inspection of the CZ areas allows engineers to quickly determine the integrity of arguably the most important area of the tank bottom.Herein we discuss notable developments in CZ coverage,inspection efficiency and data integrity that combines to deliver an actionable report.The asset owner can interrogate this report to develop pertinent and accurate maintenance and repair strategies.

Smoothed-Particle Hydrodynamics Simulation of Ship Motion and Tank Sloshing under the Effect of Regular Waves

Predicting the response of liquefied natural gas(LNG)contained in vessels subjected to external waves is extremely important to ensure the safety of the transportation process.In this study,the coupled behavior due to ship motion and liquid tank sloshing has been simulated by the Smoothed-Particle Hydrodynamics(SPH)method.Firstly,the sloshing flow in a rectangular tank was simulated and the related loads were analyzed to verify and validate the accuracy of the present SPH solver.Then,a three-dimensional simplified LNG carrier model,including two prismatic liquid tanks and a wave tank,was introduced.Different conditions were examined corresponding to different wave lengths,wave heights,wave heading angles,and tank loading rates.Finally,the effects of liquid tank loading rate on LNG ship motions and sloshing loading were analyzed,thereby showing that the SPH method can effectively provide useful indications for the design of liquid cargo ships.

Dynamic Response of A Group of Cylindrical Storage Tanks with Baffles Considering the Effect of Soil Foundation

The sloshing in a group of rigid cylindrical tanks with baffles and on soil foundation under horizontal excitation is studied analytically.The solutions for the velocity potential are derived out by the liquid subdomain method.Equivalent models with mass-spring oscillators are established to replace continuous fluid.Combined with the least square technique,Chebyshev polynomials are employed to fit horizontal,rocking and horizontal-rocking coupling impedances of soil,respectively.A lumped parameter model for impedance is presented to describe the effects of soil on tank structures.A mechanical model for the soil-foundation-tank-liquid-baffle system with small amount of calculation and high accuracy is proposed using the substructure technique.The analytical solutions are in comparison with data from reported literature and numerical codes to validate the effectiveness and correctness of the model.Detailed dynamic properties and seismic responses of the soil-tank system are given for the baffle number,size and location as well as soil parameter.

Identification of the Diffusion Coefficients of Pollutants ( N O 3 - and Mn2+) through the Walls of Concrete Tank and Vulnerability of the Stored Water Quality

The populations of urban centers in Congo-Brazzaville have decided to develop various methods of water storage (concrete or masonry underground tanks) for domestic use, due to shortages in the distribution of water through the public network. However, questions remain as to the physico-chemical quality of the water stored in these tanks, when these structures are built in wet and relatively polluted areas. This paper presents a model of pollutant diffusion through the cementitious matrix (concrete) of tank walls simulated at a buried reservoir. The results of the experimental and numerical simulations show that certain concrete parameters, such as porosity, permeability and diffusivity, have a significant influence on the transfer of pollutants through the concrete walls, thus altering the physico-chemical quality of the stored water. The numerical models (1D) used to predict pollutant transfer and the quality of the stored water are consistent with those of the optimal control for identifying the diffusion coefficient. Major ion concentrations appear to be correlated with system porosity and diffusion coefficient. Nevertheless, the identification of the diffusion coefficient from the optimal control method, based on an explicit numerical resolution of a finite volume PDE for the approximation of the experiment, is not consistent with that of the optimal control method.

Tank模型在中小河流洪水气象风险预警中的应用

结合蒲河流域的气候条件和洪水特性,利用Tank模型模拟了该流域2019~2020年10次暴雨洪水过程,构建了适用于该流域的概念性暴雨致洪气象风险预警模型,并进行仿真模拟和精度评定。结果表明,改进后的水箱模型能直观地模拟出石角水文站不同时间尺度、不同基础水位条件下的水位变化过程曲线,能减少面雨量阈值的不确定性,预报精度为乙等;根据模拟结果逐级发布气象风险预警,技巧评分和命中率为100%;平均预警发布时间提前3 h以上,可代入预测降水进一步延长洪水预报预见期。

虾稻共作产汇流过程中TANK-MIKE 11耦合模型的应用

以构建的适合于平原灌区虾稻共作田降雨-径流过程模拟的TANK-MIKE 11耦合模型为工具,对四湖流域典型虾稻共作田区进行区域排涝影响研究。模拟了在不同降雨标准下,虾稻田种植面积占比、虾稻田上限排水深等条件变化对四新垸农排区径流的影响,结果表明:在不同历时暴雨重现期下,相较于50%现有虾稻共作种植面积,当虾稻田面积为10%与90%时,外排水量分别增加6%~28%和减少3%~18%;在各种设计暴雨下,相较于1.2 m虾沟上限排水深,1.3m时洪峰流量减小3.01%~5.62%。1.4 m时洪峰流量减小5.79%~10.36%。

Analysis in Results Production Mode of Chinese Media Type Think-Tank

Purpose/Significance:Through the analysis in the results production mode of the Chinese media type think-tank based on the media operation structure and communication platform,found there are structure and cooperation problems of spread and research line,team cooperation and transformation problem of research and spread,research production and media production positioning problem,and spread channel widening problem,this paper tries to provide a useful suggestions for the current traditional media transformation encourage the media type think tank go abroad,raise the international influence,personalize the products,make it into Boutique,become a brand and the development strategy of the new think-tank with Chinese characteristics.Methods/Processes:analysis the results production model of media-based think tank from four aspects:category,characteristics,existing problems and development trend.Results/conclusion:the achievements of Chinese media-based think tanks will follow a new development trend through the establish of cooperative innovation system,achievements make and press system of“all media tendency”,market-oriented transformation theory,brand strategy,and exerting international influence.

中国智库发展及新型智库建设的政策变迁、实践探索与未来面向

在中国特色社会主义进入新时代、世界百年未有之大变局加速演进的关键时期,智库建设迎来又一个快速发展期。中国共产党历来重视智库建设,并贯穿于党的百年发展历程。改革开放前是中国共产党“智库”建设的起步阶段,各类智库性质的机构在不同时期发挥了辅助军事战争决策和汇集民智、为新民主主义建设建言的重要作用,但也存在研究活力不足、研究成果国际影响力有限等问题。改革开放后到21世纪前十年,是中国“智库”发展的再觉醒阶段,这一时期社会智库、高校智库蓬勃兴起,相继建立了地方决策咨询委员会和智库成果报送制度,有效扭转了智库成果偏重政策性解读而缺乏议题前瞻性,有对策建议而欠缺可操作性等倾向。新时代以来是中国智库的高质量发展阶段,党中央将发挥智库作用纳入党决策咨询制度化建设的范畴,高端智库试点工作全面展开,中国特色新型智库建设作为国家战略全面推进。针对不少高校智库大多只见其名未见其实、智库名称和研究领域存在较多重合等现象,党中央和主管部门分别从指导思想、发展阶段、行动步骤等方面作出了规划。作为中国新型智库建设的重要力量,高校智库要发挥人才和多学科优势,瞄准国际国内战略性、前沿性课题深入开展系统性研究并产出优秀的咨政成果,同时更加重视自然科学与工程技术在高校智库建设中的地位与作用,为促进我国科学、民主、依法决策,推动国家治理体系和治理能力现代化与经济社会高质量发展提供智力支撑。

Theoretical Analysis of Biogas Production from Septic Tanks: The Case of the City of Kinshasa

As many think that respect for the environment, is not only a question intended for industrialists but has all the sectors of life, in particular sanitary also. In this regard, our article brings alternative management of human waste (excrement) to solve the problems that plague our dear beautiful capital, namely: 1) Lack of latrines that meet the standards;2) Emptying of septic tanks directly into the gutters and;3) Water pollution by sewage csompanies. In order to carry out the cartographic analysis of the study area, we used Shapefile data from the OpenStreetMap, Diva-Gis. These different data allowed us, analyzed, to categorize with the software ArArcGIS 0.8.1 to produce different zones according to the cases incurred in the city of Kinshasa. To do this, the analytical method uses the Buswell equation to determine the amount of gas contained in human excrement. Focusing on the analysis of the excrements produced by the population of age superior to 10 years, for 2023, we obtained: 138355.7283 m3/day of CH4 (885476.66 kWh/day or 885.476 MWh/day), which, energy can light: 138,355 lamps of 60 to 100 W for six hours or nearly 70,000 lamps of 60 to 100 W for 12 hours. Considering the last one which offers the lowest access rate, i.e. 3% of the district population to these latrines, we have: a) In Tshangu, we produce: 1618.762 3>/day (10360.07 kWh/day or 10.36 MWh/day) which can light nearly 1600 lamps from 60 to 100 W for six hours or nearly 800 lamps from 60 to 100 W for twelve hours. b) Mont-Amba, we produce 1402.927 3>/day (8978.73 kWh/day or 8.97 MWh/day) which can light nearly 1400 lamps from 60 to 100 W for six hours or nearly 700 lamps from 60 to 100 W for twelve hours;c) In Lukunga, we produce: 946.35 3>/day (6056.66 kWh/day or 6.056 MWh/day) which can light nearly 900 lamps from 60 to 100 W for six hours or nearly 450 lamps from 60 to 100 W for twelve hours. d) Funa, we produce: 182.629 3>/day (1168.83 kWh/day or 1.17 MWh/day) which can light almost 180 lamps from 60 to 100 W for six hours or almost 90 lamps from 60 to 100 W for twelve hours.

Experimental Investigation on the Effect of Seal Presence on the Behavior of Double-Deck Floating Roofs in Cylindrical Steel Storage Tanks

Liquid storage,particularly oil and petrochemical products which are considered hazardous liquid,are an important part of the oil industry.Thin-walled vertical cylindrical steel storage tanks are widely used in recent years.Due to high sensitivity of these structures in an earthquake and other external excitations may lead to catastrophic consequences.For instance,huge economic losses,environmental damages,and casualities,many studies have been done about these structures.past studies showed that liquid storage tanks,equipped with a floating roof,are potentially vulnerable while subjected to seismic loads and earthquake has been considered as one of the most destructive natural hazards.The reason is that such tanks are made of two separated parts(shell and roof)which each may have its own responses;sometimes causing resonance phenomenon and so that,roof movements,rooffluid interaction,roof-shell interaction,and also the way they are attached should still be investigated.Experimental tests of floating roof’s vertical fluctuation was performed in a full-scale reservoir tank and assessing of the results demonstrated that presence of a seal between floating roof and shell plate can significantly increase damping ratio in liquid sloshing and also suppress the roof`s vertical displacements.In other words,seal can control a floating roof and make it stop moving vertically over few cycles.

Robust adaptive precision motion control of tank horizontal stabilizer based on unknown actuator backlash compensation

Backlash nonlinearity inevitably exists in the actuator of tank horizontal stabilizer and has adverse effect on the system control performance,however,how to effectively eliminate its effect remains a pending issue.To solve this problem,a robust adaptive precision motion controller is presented in this paper to address uncertainties and unknown actuator backlash of tank horizontal actuator.The controller handles the modeling uncertainties including parameter uncertainties and unmodeled disturbances by integrating adaptive feedforward compensation and continuous nonlinear robust law.Based on the backstepping method,a smooth backlash inverse model is constructed by combining the adaptive idea.Meanwhile,the unknown backlash parameters of the system can be approximated through the parameter adaptation,and the impact of the actuator backlash nonlinearity is effectively compensated via the inverse operation,which can availably improve the tracking performance.Moreover,the adaptive law can update the disturbance ranges of tank horizontal stabilizer online in real time,which enhances the feasibility in practical engineering applications.Furthermore,the stability analysis based on Lyapunov function shows that with the existence of unmodeled disturbances and unknown actuator backlash,the designed controller guarantees excellent asymptotic output tracking performance.Extensive comparative results verify the effectiveness of the proposed control strategy.

基于LDA-DLNB网络舆情识别的应急管理智库决策研究

[目的/意义]网络舆情信息在突发事件应对中有着不容忽视的传播影响力。完善舆论引导是中国特色新型智库的重要功能之一。做好网络舆情识别是应急管理智库提高综合研判能力的关键。[方法/过程]本文从应急管理智库建设角度出发,聚焦突发事件网络舆情信息中潜在的关键热点与情感结构识别问题,通过机器学习方法构建LDA-LDNB网络舆情信息挖掘模型,并基于突发事件网络舆情文本信息进行模型验证和实证分析。[结果/结论]本文构建的模型能很好地识别突发事件中网络舆情信息的主题、情感与演化特征,为应急管理智库提高应急管理决策服务能力提供方法支持,为构建数据驱动的应急管理智库提供新的思路。

“一带一路”高等教育国际化智库建设研究

高等教育国际化智库是推动“一带一路”沿线国家高等教育国际化进程的重要思想库。该智库建设有助于推动“一带一路”高质量发展。“一带一路”高等教育国际化智库围绕“一带一路”高等教育改革与高等教育国际合作中的战略性、前瞻性、系统性问题开展战略研究和政策研究,是为“一带一路”高等教育国际化发展提供决策咨询的思想库。该智库承担着助推“一带一路”倡议的持续发展,服务构建“一带一路”高等教育共同体,以及培养高等教育国际化人才的使命。因此,“一带一路”高等教育国际化智库应具有包容互鉴、协同共建、互通互信、国际化、面向未来五个特征,并围绕以下四个着力点进行建设:一是明确发展理念,落实高等教育国际化智库的使命担当;二是秉持开放合作,搭建高等教育国际化合作框架;三是促进融合互通,共享高等教育发展资源;四是以质量为核心,提高高等教育国际化智库影响力。

Effect of an Inclined Slots on the Power Consumption and Vortices Size in a Rushton Turbine Agitated Tank

Mechanical agitation in baffled vessels with turbines plays a vital role in achieving homogeneous fluid mixing and promoting various transfer operations.Therefore,designing vessels with optimal energy efficiency and flow dynamics is essential to enhance operational performance and eliminate flow perturbations.Hence,the present research focuses on a numerical investigation of the impact of inclined slots with different angles installed at the side-wall of a cylindrical vessel equipped with a Rushton turbine.This study explores power consumption and vortex size while considering various rotation directions of the impeller with different rotation speeds.The numerical simulations are conducted for Reynolds numbers ranging from 104 to 105,using the RANS k-εturbulence model to govern the flow inside the stirred vessel,accounting for mass and momentum balances.The results have shown that the installation of slots reduces power consumption and vortex size compared to conventional vessel configu-rations.Moreover,increasing the slot angle from 0 to 32.5°further reduces energy consumption and vortex size,especially with negative rotation speeds.On the other hand,increasing the Reynolds numbers leads to a decrease in power consumption and an increase in vortex size.The present research therefore proposes a design for con-structing Rushton-turbine stirred vessels offering optimal operation,characterized by reduced energy consumption and minimized vortex size.

Method for measuring the low-frequency sound power from a complex sound source based on sound-field correction in a non-anechoic tank

Similar to air reverberation chambers, non-anechoic water tanks are important acoustic measurement devices that can be used to measure the sound power radiated from complex underwater sound sources using diffusion field theory. However,the problem of the poor applicability of low-frequency measurements in these tanks has not yet been solved. Therefore,we propose a low-frequency acoustic measurement method based on sound-field correction(SFC) in an enclosed space that effectively solves the problem of measuring the sound power from complex sound sources below the Schroeder cutoff frequency in a non-anechoic tank. Using normal mode theory, the transfer relationship between the mean-square sound pressure in an underwater enclosed space and the free-field sound power of the sound source is established, and this is regarded as a correction term for the sound field between this enclosed space and the free field. This correction term can be obtained based on previous measurements of a known sound source. This term can then be used to correct the mean-square sound pressure excited by any sound source to be tested in this enclosed space and equivalently obtain its free-field sound power. Experiments were carried out in a non-anechoic water tank(9.0 m × 3.1 m × 1.7 m) to confirm the validity of the SFC method. Through measurements with a spherical sound source(whose free-field radiation characteristics are known),the correction term of the sound field between this water tank and the free field was obtained. On this basis, the sound power radiated from a cylindrical shell model under the action of mechanical excitation was measured. The measurement results were found to have a maximum deviation of 2.9 d B from the free-field results. These results show that the SFC method has good applicability in the frequency band above the first-order resonant frequency in a non-anechoic tank. This greatly expands the potential low-frequency applications of non-anechoic tanks.