Numerical investigation of the effects of soil-structure and granular material-structure interaction on the seismic response of a flat-bottom reinforced concrete silo

In this work,a numerical study of the effects of soil-structure interaction(SSI)and granular material-structure interaction(GSI)on the nonlinear response and seismic capacity of flat-bottomed storage silos is conducted.A series of incremental dynamic analyses(IDA)are performed on a case of large reinforced concrete silo using 10 seismic recordings.The IDA results are given by two average IDA capacity curves,which are represented,as well as the seismic capacity of the studied structure,with and without a consideration of the SSI while accounting for the effect of GSI.These curves are used to quantify and evaluate the damage of the studied silo by utilizing two damage indices,one based on dissipated energy and the other on displacement and dissipated energy.The cumulative energy dissipation curves obtained by the average IDA capacity curves with and without SSI are presented as a function of the base shear,and these curves allow one to obtain the two critical points and the different limit states of the structure.It is observed that the SSI and GSI significantly influence the seismic response and capacity of the studied structure,particularly at higher levels of PGA.Moreover,the effect of the SSI reduces the damage index of the studied structure by 4%.

“圆筒社会”的哲学启示——评美剧SILO

美剧SILO讲述了未来末日中生活在圆筒世界中的人们,试图离开筒仓追寻自由,一步步发现筒仓秘密,揭开一切真相的过程。本文结合阿尔都塞的意识形态和意识形态国家机器理论、居伊德波的《景观社会》中的观点及马克思·韦伯的“现代性铁笼”的思想,结合西方近现代电影中的“反乌托邦”主题试图分析本剧的深层结构,分析电影的意识形态内核及其背后想要表达的核心观点。

Comparative Analysis of PM10 Emission Rates from Controlled and Uncontrolled Cement Silos in Concrete Batching Facilities

This research study quantifies the PM10 emission rates (g/s) from cement silos in 25 concrete batching facilities for both controlled and uncontrolled scenarios by applying the USEPA AP-42 guidelines step-by-step approach. The study focuses on evaluating the potential environmental impact of cement dust fugitive emissions from 176 cement silos located in 25 concrete batching facilities in the M35 Mussafah industrial area of Abu Dhabi, UAE. Emission factors are crucial for quantifying the PM10 emission rates (g/s) that support developing source-specific emission estimates for areawide inventories to identify major sources of pollution that provide screening sources for compliance monitoring and air dispersion modeling. This requires data to be collected involves information on production, raw material usage, energy consumption, and process-related details, this was obtained using various methods, including field visits, surveys, and interviews with facility representatives to calculate emission rates accurately. Statistical analysis was conducted on cement consumption and emission rates for controlled and uncontrolled sources of the targeted facilities. The data shows that the average cement consumption among the facilities is approximately 88,160 (MT/yr), with a wide range of variation depending on the facility size and production rate. The emission rates from controlled sources have an average of 4.752E-04 (g/s), while the rates from uncontrolled sources average 0.6716 (g/s). The analysis shows a significant statistical relationship (p < 0.05) and perfect positive correlation (r = 1) between cement consumption and emission rates, indicating that as cement consumption increases, emission rates tend to increase as well. Furthermore, comparing the emission rates from controlled and uncontrolled scenarios. The data showed a significant difference between the two scenarios, highlighting the effectiveness of control measures in reducing PM10 emissions. The study’s findings provide insights into the impact of cement silo emissions on air quality and the importance of implementing control measures in concrete batching facilities. The comparative analysis contributes to understanding emission sources and supports the development of pollution control strategies in the Ready-Mix industry.

A general method for silo classification using rupture plane

A new method is presented for silo classification using the rupture plane in the storage. The proposed method is based on the formula of rupture plane orientation determined by the aspect ratio of specified silos and involves the effects of the conical angle of the storage surface, so it can deal with two cases： the conical angle of the storage surface and the flat storage surface. Compared with the two popular methods based on the silo-aspect ratio and the silo rupture plane, respectively, in current engineering design, the new method can give a range of critical aspect ratios to classify deep silos and squat silos according to the conical angle of the storage surface or the fiat storage surface. Moreover, the range covers the critical aspect ratios obtained from the existing classification methods including the Chinese code based on silo aspect ratios, the German code, Reimbert brothers＇ definition and Liang et al. ＇s definition, so it is a more general method to classify silos and the existing methods can be viewed as special cases of the presented method.

12例巨型脐膨出新生儿应用新型silo袋行分期修复术后的护理

总结12例巨型脐膨出新生儿应用新型silo袋行分期修复术后的护理经验。其护理要点包括:低体温新生儿做好保暖,掌握囊膜及肠管的监护注意事项;巨型脐膨出回纳后,常引起腹内压增高,密切观察血液循环及呼吸情况;做好silo袋卡扣处皮肤护理,预防伤口感染;根据患儿喂养耐受情况做好营养支持。12例巨型脐膨出新生儿应用新型Silo袋行分期修复术,经积极处理与精心护理后病情好转,其中1例因家庭经济原因病情好转要求自动出院,余11例治愈出院。

基于Silo的科学计算结果数据的管理与可视化

在某数值模拟可视化软件研制中,为了对不同类型的数值模拟结果进行统一管理和可视化,采用Silo格式文件管理数值结果,并将其应用于可视化工具VisIt中。对MCNP,FDTD,Fluent等数值模拟程序计算结果中的曲线、网格及相关联的标量、矢量等数据进行提取,写为Silo格式文件,并给出了其在VisIt中的可视化效果。结果表明:不同类型的数值模拟结果数据可通过Silo格式文件进行综合管理,并可在VisIt中得到高效的可视化。

Cemented backfilling technology with unclassified tailings based on vertical sand silo

A new technology characterized by rapidly non-mechanical settlement of unclassified tailings was developed based on a large number of tests, and dynamic settlement and continual slurry preparation without hardening in vertical sand silo were eventually realized by the addition of an effective flocculating agent (NPA). The results show that the sedimentation velocity of interface between unclassified tailings and water after the addition of NPA increases by 10-20 times, the sedimentation mass fraction of unclassified tailings at the bottom of vertical sand silo is up to 64%, the solid particle content of waste water meets the national standard, and the side influences of NPA can be removed by the addition of fly ash. The industrial test result shows that the system, the addition manner and the equipments are rational, and the vertical sand silo is used efficiently. This developed system is simple with large throughput, and the processing cost is 2.2 yuan(RMB)/m3, only 10%-20% of that by mechanical settlement.

一期缝合与应用免缝腹裂袋“silo”分期修复先天性腹裂的疗效对比

目的对比一期缝合修复术与silo技术分期修复治疗先天性腹裂的疗效。方法先天性腹裂新生儿43例,其中一期缝合修复19例(一期组),silo技术分期修复24例(silo组),观察两组手术情况及并发症。结果两组患儿均顺利完成手术,围术期均无死亡病例。silo组拔管时间、肠内营养时间、住院时间均明显短于一期组(P<0.05)。silo组术后伤口愈合不良、肠梗阻、生长发育迟缓等并发症总发生率低于一期组(P<0.05)。结论 silo技术分期修复治疗先天性腹裂安全、有效,可缩短住院时间。

筒仓结构设计软件SILO简介

筒仓结构是一种工业构筑物。介绍了一种专门针对筒仓结构的设计软件，该软件能够自动计算作用在筒仓结构上的各种荷载，并自动进行工况组合以及配筋计算。测试表明，该软件的计算分析是稳定和高效的。

Determination of the causes and the effects of storage conditions on the quality of silo stored wheat(Triticum aestivum)in Zimbabwe

There are still cases of millers returning poor quality red wheat to the Zimbabwe Grain Marketing Board(GMB)and this has been an ongoing problem over the past few years.A larger amount of this wheat has discoloured and damaged embryos and it is discounted by millers because the germs are brittle and they crumble easily.There have been also many rejections of the red wheat particularly by major traders.Therefore there was an urgent need to investigate the causes and effects of storage conditions on the quality of silo-stored red wheat,since red wheat is one of human beings’main food supplies.A representative sample of 2.25 kg of red winter wheat was randomly collected from the common red winter wheat incoming to the Grain Marketing Board Depot for storage.This representative sample of 2.25 kg was used as the control sample and its test density was determined.The control sample was then finely ground and analysed for protein,moisture,ash,aflatoxins and falling number.The red winter wheat was then stored in six different silos for a period of 5 months,with each silo having different humidity and temperature conditions.Representative samples of 4.5 kg were randomly collected monthly from each silo during the storage period.The test densities of the representative samples were determined.These representative samples were then finely ground and analysed for protein,moisture,ash,aflatoxins,and falling number.The results of the red wheat in storage were then compared with those of the control sample and analysed by analysis of variance(ANOVA)at the 5%level of significance.Results obtained after data analysis suggest that there were significant differences in the protein content,moisture content and falling number of the wheat before and after storage.However,differences in test density,aflatoxin and ash contents of the wheat before and after storage were not statistically significant at the 5%level of significance.The deterioration in wheat quality was attributed to the high storage tempera-ture and humidity conditions.It was also concluded that the optimum conditions for wheat storage are a temperature of 15 oC and a humidity of 60%.

Design of infrared camouflage cloak for underground silos

The temperature difference between the exposed surface of an underground silo and the surrounding soil surface is significant,which means a silo can be easily found by infrared detection.We designed an infrared camouflage cloak consisting of an imitative layer and an insulation layer for the silos.The imitative layer is used to imitate the thermal response of the soil to the surrounding environment.The insulation layer is used to weaken the impact of the internal temperature field of the silo on the lower boundary of the imitative layer.A silo model including surrounding soil and a soil model without silo were established,and the influences of the material and thickness of each layer on the infrared camouflage effect were analyzed.The results show that when using a silicone rubber containing alumina powder with a volume fraction of 3.18% as the imitative material,its thermal inertia is in consistent with that of the soil.Meanwhile,it was found that the thickness of the imitative layer doesn't need to be greater than its thermal penetration depth to achieve the infrared camouflage,and the absence of the insulation layer will cause hot spots on the silo surface in winter to weaken the camouflage effect.The optimized thicknesses of the imitative layer and the insulation layer are 22 cm and 4 cm re spectively.The simulations indicate that with the application of the cloak,the maximum value of the absolute values of the temperature differences between the average temperatures of the silo surface and the surrounding soil surface temperatures drops from 1,59℃ to 0.31℃ in summer and from 1.92℃ to 0.21℃ in winter.This designed cloak can achieve an all-weather and full-time passive infrared camouflage.

ECT Image Analysis Methods for Shear Zone Measurements during Silo Discharging Process

The paper covers the electrical capacitance tomography(ECT) data analysis on shear zones formed during silo discharging process.This is due to the ECT aptitude for detection of slight changes of material concentration.On the basis of ECT visualisations,wall-adjacent shear zone profiles are analysed for different wall roughness parameters.The analysis on changes of material concentration,based on ECT images,enables the calculation for the characteristic parameters of shear zones-size and material concentration inside the shear zone in a dynamic process of silo discharging.In order to verify the methodology a series of experiments on gravitational flow of bulk solids under various conditions were conducted with different initial granular material packing densities and silo wall roughness.The investigation shows that the increase in container wall roughness is an effective method for reducing the dynamic effects during the material discharging,since these effects are resulted from the resonance between hopper construction and trembling material.Such effects will damage industrial equipment in practical applications and need further investigation.

Laser triangulation measurement of the level in a coal silo

Laser triangulation theory was used to develop a novel contact-free method for measuring the coal level in a silo under harsh environmental conditions found in coal mines, such as the presence of dense dust, high humidity, and low illumination. A laser source and a camera were mounted at the top of the silo. The laser spot projected into the silo was imaged by the camera. The pinhole imaging principle allows the level to be found from the lateral shift of the spot image on the sensor. A pre-calibrated look-up table of the coal depth versus spot position was used to obtain the depth. The measurement accuracy depends on the step size used during pre-calibration. The actual application of a device designed according to these principles shows that it is easy to implement. The detection of the coal level in a silo at the low illumination level found in coal mines is demonstrated.

Lateral Pressure of RC Silos with Static and Dynamic Granular Materials

This paper aims at analyzing material-induced lateral pressure of RC cylinder silo in both static and dynamic condition using the finite element method( FEM). In the finite element software ABAQUS,concrete material is modeled by concrete damaged plasticity model,and stored materials in silo is modeled by the hypoplastic theory.In terms of numerical model,shell elements( S4R) and solid elements( C3D8) are applied for model silo wall and stored materials respectively. The interaction between silo wall and stored materials is simulated by Coulomb friction model and penalty contact constrain provided by ABAQUS.The numerical results are verified with the existing experimental data that are designed to ensure the validation of such numerical model using FEM and it obtains good agreements between numerical results and experimental data. Then the material parameters are analyzed in both static and dynamic condition.According to the analysis,it is clear that critical friction angle,initial void ratio and minimum void ratio have an obvious effect on static lateral pressure while all the material parameters affect dynamic lateral pressure at different levels. In addition,differences of silo wall between elastic and plastic state are analyzed in dynamic condition. The numerical results show that it contributes to increasing dynamic pressure when silo wall enters into the plastic state. Finally,this paper discusses the time-history lateral pressure at different heights along silo wall,and analytical results indicate that larger acceleration values play main roles in producing the maximum lateral pressure at higher part of the silo wall.

Discharge characteristics of coal and extraction residue from direct coal liquefaction in partial fluidization silo

Gasification of extraction residue(ER) from direct coal liquefaction with pulverized coal is an efficient way for the utilization of carbonaceous wastes, which improve the overall efficiency of direct coal liquefaction technology. The discharge characteristics of ER mixing with pulverized coal is important paraments for its gasification process, which is seldom studied in the literature. In this study, the discharge characteristics of the pulverized coal(M1) as well as its mixture with ER(M2) were systematically investigated in an atmospheric pressure partial fluidization silo with different fluidization apparent velocity. It was observed that although M2 is a viscous powder with lower flowability than M1, the mass flow rate of M2 is 65% higher than M1 at the 3.7 mm·s-1apparent gas velocity. M2 exhibits the properties of Geldart A type powder, which improves the mass flow rate and stability of the discharged material. The mass flow rate of both M1 and M2 first increases and then slowly decreases with the increase of apparent gas velocity of the fluidizing air, which means the discharge process of M1 and M2 can be optimized by the apparent gas velocity.

An Experimental Study on Gravity Blending Silo with an Inner Downcomer

A novel gravity blender with an inner downcomer was experimentally studied in this work. The flow characteristics of solid through the downcomer with branch pipes and the influence of the number of intake openings and their axial position along the downcomer on blending efficiency were investigated. The results of tracer experi-ments show that better blending quality can be obtained if the intake openings along the downcomer are designated according to the equal time interval principle. More intake openings are beneficial for blending efficiency, and the solids flow rate through the branch pipes along the downcomer can be predicted by the Beverloo equation.

An Experimental Study on Distribution of Vertical Stress in a Silo with a Central Inner Downcomer

The distribution of vertical stress for both active and passive state in the silo with a central innerdowncomer is reported in this paper. Experimental measurement of the axial distribution of vertical stress for bothactive and passive state in the silo are in good agreement with that predicted by theoretical analysis. The meanaxial stress is reduced due to the presence of the inner downcomer in the silo.

Seismic Analysis of Reinforced Concrete Silos under Far-Field and Near-Fault Earthquakes

Silos are strategical structures used to stockpile various types of granular materials.They are highly vulnerable to earthquake excitation and have been frequently reported to fail at a higher rate than any other industrial structure.The seismic response of silos within the near-fault region will suffer a complex combination of loadings due to the unique characteristics of the near-fault ground motions;which are usually associated with a large amplitude pulse at the beginning of either the velocity or the displacement time histories.This study aims to numerically evaluate the seismic response of reinforced concrete cylindrical silos under near-fault ground motions(NFGM)and far-field ground motions(FFGM).The assessment investigates the impact of the slenderness ratio and the para-meters’influence on the seismic behavior of reinforced concrete silos.The validity of the Eurocode provisions in the structural safety of silos will also be inspected.The nonlinear time history analysis is carried out through the finite element approach by examining four silos with different slenderness ratios.The concrete damage plas-ticity model is assigned to the silo wall to simulate the nonlinear behavior of concrete in the plastic zone;while,the behavior of the stored material is represented by the Drucker-Prager plastic model.The wall-granular material interaction is considered and defined by coulomb’s friction theory.The results of the near-fault records reveal a growth up to 72.8%in the hoop stress and 160.4%in the vertical stress compared to the far-field earthquakes.Consequently,the seismic response of reinforced concrete silos is highly sensitive to the type of ground motion,and slender silos tend to impose greater structural demand under the NFGM.Additionally,The Eurocode-8 seismic provisions were adequate in the conventional far-field ground motions and less effective in the near-fault zone.

PC-Based Automated Control System for Jordan Northern Grain Silo

This paper presents a PC-based automated control system operation of the Northern Grain Silo of Jordan. The system connects to a PLC (programmable logic controller) device, and combines operator interface, PLC programming and monitoring functions into one platform. The PLC portion handles direct operations control, while the PC portion handles interfacing and data intensive functions. A simulation package is developed. The package generates a graphical user interface for real-time graphic animations of the Grain Silo operation. We discuss anticipated benefits of such a system and phases of implementation.