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Copyright of Revue Archéologique de Picardie is the property of Revue Archeologique de Picardie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Static stress of granular materials stored in silos is important for the security of materials during storage. Janssen equation was commonly used to calculate the static stress of grains in silos, but later researchers found the equation underestimated loads in storage bins. In this paper, the modified Cam-clay model was applied to study the stress distribution of wheat piles at four moisture levels, stored in a circular flat bottom silo, at different grain depth and radius of silos. The results showed that as the grains depth increased, the vertical stress of wheat piles increased except the wall-bottom of silos, and the lateral stress increased except the center of silos near bin bottom. Moreover, it was found that as the radius increased, the vertical stress of wheat piles decreased at the same depth and moisture content, and the lateral stress decreased but increased near the bin bottom in the same case. When the mean stress of a layer of grains were observed, it was found that the lateral stress was negatively correlated with moisture content when the vertical stress had no concern with it at the same grain depth and all of them approached the maximum at the same moisture content. [ABSTRACT FROM AUTHOR]

Using theory and experiments, we investigate granular surface avalanching due to material outflow from a narrow silo. The assumed silo geometry is a deep rectangular box, of moderate spanwise width and small gap thickness between smooth front and back walls. A small orifice deep below the free surface lets grains drain out at a constant rate. The resulting granular flows can therefore be assumed quasi-two-dimensional and quasi-steady over most of the surface descent history. To model these flows, we couple a kinematic model of deep granular flow with a dynamic model of shallow surface avalanching. We then compare the calculated flow fields with detailed particle tracking measurements, letting the silo ascend relative to the high-speed camera to increase spatial resolution. The results show that the avalanching surface shape and near-surface flow are controlled by the spanwise gradient in subsidence velocity, and how this gradient is in turn controlled by the height above orifice and the gap thickness. Whereas the deep flow pattern is rate independent, shallow avalanching is paced by the granular rheology. [ABSTRACT FROM AUTHOR]

Concrete silos are one of the most robust and reliable structures for grain storage in tropical countries. This study analysed the structural behavior of a low cost, flat bottom bamboo-reinforced concrete (BRC) silo for rough rice storage. This research included the design and development of a BRC silo in accordance with the guidelines mentioned by the Indian Standard (IS) codes. The Finite Element Method was employed to develop the stress profile in the silo walls under "grain at rest" and "grain filling" conditions. The results obtained were further compared with experimental results, classic silo theories (Janssen's theory) and standards of different countries in the world. The numerical technique gave stress magnitudes very close to those of the experimental results. The classic theories as well as the standards of different countries predicted an over estimation of the magnitude of stresses in the BRC silo. This would result in extra cost of construction of BRC silos. The study also suggested that the vertical stresses were most predominant under static and filling conditions. Maximum stresses were developed at the silo bottom. This study is expected to aid the development of economical silos with minimum wall thickness and material requirement which are ideal for on-site construction and use by smallholder farmers. [ABSTRACT FROM AUTHOR]

Highlights • Fraction size and moisture content affected the hopper half angle. • The hopper half angle decreased with increase in angle of wall friction. • The adjusted hopper outlet sizes varied between 1.20 and 28.56 mm. • Initial fill and flow induced pressures increased with increase in fraction size. • Initial fill and flow induced pressures increased with decrease in moisture content. Abstract Bulk material handling operations are key operations in process industries such as biorefineries, chemicals and pharmaceuticals. To ensure a successful production operation, a consistent and reliable flow of the materials from storage vessels without dust generation and flow obstruction are required. The objective of this study was to investigate the effect of particle size and moisture content on the theoretical estimation of silo design parameters for fractionated loblolly pine grinds. Loblolly pine grinds were fractionated into sizes using screen apertures: 1.40, 1.00, 0.71, 0.50, 0.25 mm and pan. The fractionated loblolly pine grinds were adjusted to the moisture level of 4.78%, 8.68%, 16.53%, 22.21% and 25.53% (w.b). There was a reduction in the hopper half angle with increase in moisture content and reduction in the fraction size. The hopper half angle also decreased with increase in angle of wall friction. The adjusted hopper outlet sizes varied between 1.20 and 28.56 mm. The wall normal and vertical pressure acting on the cylindrical section of the silo increased from 9.35 to 45.42 kPa and 15.34 to 48.91 kPa, respectively, with increase in fraction size and decrease in moisture content. The initial fill and flow induced pressures acting on the hopper section of the silo increased from 15.34 to 48.91 kPa and 24.71 to 78.79 kPa, respectively, with increase in fraction size and decrease in moisture content. Results of this study will be helpful in designing effective storage vessels and understanding the pressures exerted by stored biomass in the storage vessel. [ABSTRACT FROM AUTHOR]

With the requirement of environmental protection, reinforced concrete silos with large diameter for coal storage were built. In view of less literatures on the effect of temperature patterns, this paper presents the experimental study and 3D FEM simulation of a reinforced concrete silo with 136.5 m in diameter and 19.35 m in height. The stresses of circumferential and vertical steel bars were measured by the vibrating string strain gauges installed under different circumstances of temperature patterns due to sunshine and season changing. The data were collected and transmitted with GPRS transmission system for a period of more than 1000 days. Meanwhile, finite element model was built by ABAQUS software, in which the Drucker-Prager elasto-plastic criterion and the elasto-plastic damage model were used to modify the nonlinearity of soil and reinforced concrete. The test data agree well with the numerical simulation results. The effect of temperature patterns on silo wall was scrutinized. The results of this paper provide a crucial basis for the design of large scale silos. [ABSTRACT FROM AUTHOR]

As polymer powders have high resistivity, they can easily be charged due to the repeated collision and separation of particles along with particle-wall friction in a pneumatic conveying system. This study experimentally investigated the electrostatic charges and discharges inside a conical-cylindrical silo during the loading of polypropylene (PP, 2–3 mm) powders. The silo was continuously loaded with PP powders at 0.68 kg/s to a total mass of approximately 800 kg. To measure electrostatic charges of the PP powder being loaded into the silo, a Faraday cage with a cover was set at a distance of 50 mm from the center of the loading pipe inside the silo. To observe electrostatic discharges inside the silo, an image-intensifier unit was set on the windowpane of the silo roof. The results show that the charge-to-mass ratio of the loading PP powder remained at a constant value of approximately −12 μC/kg. The ring-shaped light, which is the electrostatic discharge, appeared clearly at the center of the silo approximately 7 s after initial loading. The diameter of the ring-shaped light grew larger as time passed after loading. This was because the diameter of the accumulated PP powders increased in the silo during the running time, meaning that electrostatic discharge occurred between settled PP powders and the grounded metal silo wall. Additionally, the electrostatic discharges during the loading of powder in this study were clearly observed and classified into three kinds of discharges: brush, linear, or broad bulk surface discharges. [ABSTRACT FROM AUTHOR]

The discharging in silo presents the characteristics of mass flow in the upper part and funnel flow in the lower part. Obviously, there is a special position where the flow pattern transition occurs. To clarify the special position of flow pattern transition during discharging of rice particles in conical silos, by means of Discrete Element Method (DEM), the change in flow characteristics was analyzed in terms of the velocity, porosity and orientation of particles. Furthermore, the effects of silo geometry parameters on the special position were discussed. The results showed that the flow characteristics change significantly during the flow pattern transition, expressing as that velocity, porosity and particle orientation change respectively from uniform to uneven, small to large and horizontal to vertical. Based on these variations, the special position of flow pattern transition is defined as the critical height and can be determined by a special change rate of velocity. Moreover, the critical height increases with increasing hopper half angle or silo diameter, while it remains nearly constant first and then decreases with the increase in outlet size. Finally, the mathematical model between the silo geometry parameters and the critical height was established. Overall, the results are useful for understanding the change in flow characteristics of rice particles during discharging and further provide guidelines to the appropriate design of conical silos. [ABSTRACT FROM AUTHOR]

Thermal cracking can pose a threat to a mass concrete structure increasing concerns over their serviceability and performance. This is the key issue surrounding engineered barriers in the nuclear industry, because the primary objective of such structures is to isolate radioactive hazards from the human environment. The present study focuses thermal stress analyses of a silo in a radioactive waste repository considering construction conditions (i.e., the temperature of the concrete and air and the boundary conditions of the structures). In addition, cracking risk is discussed according to the construction conditions based on the numerical analysis results. In the analysis results, it was found that the magnitude of the thermal stress in the silo varied according to the construction conditions. The temperature difference between the ambient and concrete, the ambient temperature, and the magnitude of external constraint were critical factors that influenced thermal stress in the silo. [ABSTRACT FROM AUTHOR]

The Lesser Date Moth, Batrachedra amydraula (Lepidoptera: Batrachedridae), is a key pest of date palms in silos and storages. The efficacy of aluminium phosphide (Phostoxin® tablet 55%) @ 5 t/m3 and magnesium phosphide (Degesch® plates 56%) @ 2 p/30 m3 were assessed against this pest in Iran date silos based on a completely randomized block design. Based on Henderson-Tilton formula, on the third day after treatment, both treatments resulted in 100% mortality. Application of magnesium phosphide and aluminium phosphide can be a suitable substitution for methyl bromide, which has just been banned in many countries. [ABSTRACT FROM AUTHOR]

The “Eurocode 1 – Actions on structures – Part 4: Silos and tanks” EN 1991-4 includes dust explosions as an accidental action for load combination in some design situations. Venting is the most widely used method to mitigate the effects of explosions. The area size of the venting devices installed in the silo will determine the development of internal overpressures in the event of an explosion, and thus the structural design of the silo. Also, the inertia and the activation pressure of the venting elements can influence the explosion pressures. The Eurocode 1 suggests using the German DIN-Report 140 to design the venting devices. However, other methods exist, such as the European standard EN 14491 and the American standard NFPA 68, which were not specifically developed for silos. In this study, the DIN-Report 140 has been analysed by calculating a wide range of cases, including different silo dimensions, materials (barley and wheat flour) and values of inertia and activation pressure of the venting devices. Three types of venting systems have been considered: bursting panels, explosion doors and light-weight concrete slabs. In addition, the DIN-Report 140 has been compared with current European and American venting standards. The results obtained in this study indicate that there are marked differences between the three methods considered, and that vent areas calculated according to DIN-Report 140 for either bursting panels or explosion doors seem to be very conservative. Uncertainties and limitations of DIN-Report 140 have been detected and discussed. The final goals of this study are to provide guidance on the determination of explosion loads and to contribute to the development of a single common practice for venting in silos. [ABSTRACT FROM AUTHOR]

Large steel silos are widely used to store huge quantities of granular solids in industry and agriculture. In the present analysis, a novel type of silo structure, designated the cellular silo, is proposed and discussed. The performance advantage of the cellular silo is the clustered construction of individual hexagon silos, which can be formed by different numbers and arrangements of cell silos. The structural system is firstly determined for the cell silo by comparison between the plate model and 3D-stiffened plate models, and it is shown that the 3D-stiffened plate assembly composed of shell elements and beam elements is feasible for the cell silo, which is quite distinct from the shell structure fit for circular silos. The horizontal solid pressure, which is beneficial to circular silos, is unfavourable to the buckling of cell silos, and the buckling design is governed mainly by the horizontal pressure rather than the vertical frictional pressure. The buckling behaviour of group silos is investigated by considering load cases defined by the number of working cell silos and their relative position in the group. The common features of group silos during buckling are summarized, and it is referential for structural design of a cellular silo. An illustrative example of a cellular silo is presented at the end to demonstrate the design procedure, and it is concluded that the buckling design of the cellular silo is governed by the full loading condition and can be completed by optimization of the cell silos and their combinations. [ABSTRACT FROM AUTHOR]

This paper presents some problems connected with causes of reinforced concrete silos failure. Reinforced concrete silos and other shells were built for decades. Vitality i.e. durability of cracked silo walls are one of the most important parameters during designing process, constructional and exploitation time of these shells. Some reasons of appearance of horizontal and vertical cracks as temperature, pressure of stored material, live loads e.g. wind, dynamic character of wind, moisture, influence of construction joints, thermal insulation, chemistry active environmental etc. reduce the carrying capacity of the walls of the silos and causes lower the state of reliability. Horizontal and vertical cracks can cause corrosion of concrete and steel bars, decreasing stiffness of contraction, bigger deflection, increasing of carbonation of concrete cover and dank of concrete wall. Horizontal and vertical cracks allow condensate water infiltrates into wall. Local and global imperfactions of concrete shells are increasing according to greater number of cracks. Taking into account these facts, reducing of strength parameters reduce the service life of the whole reinforced concrete structure causing failure status. The technology of repairing cracked walls must take into consideration the model of failure, simple one parameter or complex as series or parallel system models. [ABSTRACT FROM AUTHOR]

Vented dust explosion tests have been conducted in an experimental test silo in order to analyse the effect of the length/diameter ratio (L/D). The modular design of the silo permitted the assembling of four different vessels with different geometries. The tests were carried out with wheat flour and maize starch, using three different vent area sizes. The silo was equipped with instrumentation which recorded the pressure generated by the explosion at various points in the silo, as well as the instant when the vent panel opened. The length/diameter ratio has been included in the empirical correlations currently employed in standards EN 14491 and NFPA 68 for calculating the size of vents. However, there are marked differences between the two standards when applied to certain situations, in part due to a different vent area correction for slenderness. The results obtained in this experimental test programme were compared with the standards, and indicated the advisability of applying an increase in vent area in elongated vessels when L/D > 1, as stated in EN 14491. However, this same standard appears to apply an excessively severe correction in some situations. [ABSTRACT FROM AUTHOR]

For the past three decades, the Saudi construction industry (SCI) has exhibited poor performance. Many research efforts have tried to identify the problem and the potential causes but there have been few publications identifying ways to mitigate the problem and describing testing to validate the proposed solution. This paper examines the research and development (R&D) approach in the SCI. A literature research was performed identifying the impact that R&D has had on the SCI. A questionnaire was also created for surveying industry professionals and researchers. The results show evidence that the SCI practice and the academic research work exist in separate silos. This study recommends a change of mindset in both the public and private sector on their views on R&D since cooperation is required to create collaboration between the two sectors and improve the competitiveness of the country's economy. [ABSTRACT FROM AUTHOR]

In many cases problems in silos may occur due to improper design of its geometry due to the nonconsideration of the flow properties of the material. One of the factors that affect the flow properties of materials is the moisture content, which allows the formation of cohesive arches in the material inside the silo avoiding the desirable mass flow type. Therefore, this paper aimed to analyze the flow properties of the red mud, for different moisture levels, in order to design a hopper that provide a mass flow in conical silos. Initially, the flow properties of red mud were determined by laboratory testing using the Jenike shear tester, and then the design of the silo hopper was performed using Jenike and Enstad theories, i. e., the minimum diameter and angle of inclination of the hopper were determined for each moisture level. In order to validate the theoretical results, experimental results were obtained in laboratory for red mud powder using acrylic silos with different hoppers. The experimental results were found in good agreement with the theoretical results. [ABSTRACT FROM AUTHOR]

The paper presents 3D numerical analysis results on the effect of bulk solid on strength and stability of metal cylindrical silos with corrugated walls (without stiffeners) during filling. The behaviour of two bulk solids (dry sand and wheat) was described with a hypoplastic constitutive model. Non-linear FE analyses with both geometric and material non-linearity were performed. The numerical results were compared with the Eurocode formulae. The strengthening effect of the stored solid, wall thickness, solid granular hardness, initial void ratio of solid and wall friction angle on buckling strength was investigated. The major contribution of the paper is the quantitative estimation of the effect of the bulk solid stiffness on the silo stability and wall stresses. [ABSTRACT FROM AUTHOR]

The seismic behavior of flat-bottom silos containing grain-like material still presents strong uncertainties and current design codes tend to provide too conservative formulations for the estimation of the seismic actions. Over the years, some researchers focused on the dynamic behavior of such silos mainly through numerical investigations. Analytical formulations for the evaluation of the pressures exerted by the ensiled grain on the silo wall under seismic excitation were developed by Younan and Veletsos (J Struct Eng ASCE 124(1):62-70 ) and, more recently, by Silvestri et al. (Bull Earthq Eng 10(5):1535-1560 ). Experimental shaking-table tests were performed on silo specimens (Silvestri et al. EESD , submitted), which showed good agreement with the Silvestri's analytical formulations, even if some theoretical limits of validity were not satisfied. This has encouraged a complete revision and refinements of the theoretical framework, which is the object of this paper. In detail, the static and the dynamic actions exchanged between different grain portions and between the grain and the silo wall are idealised in a more physically consistent way. The analytical developments are carried out by means of simple free-body dynamic equilibrium equations. The refinements yield to a significant extension of the theoretical limits of validity and to a new set of analytical formulas for the wall pressures and for the wall shear and bending moment. A comparison of the analytical formulas with (i) the consolidated Janssen (Zeitschrift des vereines deutcher Ingenieure 39:1045-1049 ) and Koenen (Centralblatt der Bauverwaltung 16:446-449 ) theory for static design of silos and (ii) with the Eurocode 8 provisions for seismic design of silos and with the experimental results is also performed in order to (i) check the updated theoretical model in static conditions and (ii) verify the reliability of the different formulations in accelerated conditions, respectively. The refined theory confirms that the portion of ensiled material that interacts with the silo wall is significantly smaller than the effective mass suggested by Eurocode 8. [ABSTRACT FROM AUTHOR]

This study assesses the impact of training sheet metal workers in Kenya on their uptake of learned skills and their income. Fifty-eight artisans trained in the construction of metal silos for hermetic grain storage were compared to a random sample of 123 untrained artisans. Results show that two-thirds of the trained artisans were making the silos, half of these in their own workshops and half as employees. The probability of using the skills learned declined with age but increased with previous experience in technical work. The training did not significantly increase the income of employed artisans, but increased the annual income of those who made the silos in their own workshops by KSh315,173 (about US$3,600). The overall impact could be improved by better targeting of trainees, by using apprenticeships as an alternative mode of training, and by encouraging entrepreneurship through business training and provision of credit. [ABSTRACT FROM AUTHOR]

Numerous codes and standards specify means to calculate material-induced loads that are needed to design silos. The three most commonly used of such codes do not provide users with consistent information, and many common silo design conditions are not covered. A brief description of each code and its limitations is provided, and common design conditions not covered by any code are identified. [ABSTRACT FROM AUTHOR]

This paper deals with problems connected with the design and operation of thin-walled steel silos for storing pelleted materials. A failure of a faultily designed silo is described and its causes are examined. The parameters of the stored material were determined. The exceptional (unforeseen) loads produced by arching and their consequences were analysed. In order to compare the effect of calculation assumptions on the degree of use of the load-bearing capacity of the stringer its buckling capacity under the stored material load alone was checked. On the basis of the analyses the probable course of the events leading to the failure was determined. It is pointed out that the exceptional loads and the disturbance of the bulk material flow by silo structural and technological fittings need to be taken into account in the design of silos. [ABSTRACT FROM AUTHOR]

Silos in the form of a cylindrical metal shell are commonly elevated to provide access to the space beneath, permitting the contained materials to be directly discharged. A few discrete column supports at evenly spaced intervals are commonly used. However, the structural design of discretely supported cylindrical shells presents a variety of challenges. The presence of discrete supports results in circumferential nonuniformity in the axial compressive stress as well as a progressive vertical decay above the support. Several approaches can be adopted in design depending on the severity of the nonuniformity of the stresses. Relevant research to date has focused mostly on the behavior of cylinders supported on brackets, local forces at the base, or stiff ring beams. The use of intermediate ring stiffeners to provide circumferential uniformity in the axial membrane stresses has long been recognized, but few studies have given a clear view of the practical requirements for such rings. In this paper, a combination of base and intermediate ring stiffeners is explored to develop a practical and cost-effective solution that leads to more uniformity in the axial membrane stresses above the intermediate ring stiffener. For the purposes of obtaining a simple analytical solution, the cylindrical shell is subjected to the fundamental harmonic of the column support and analyzed using membrane theory. It is shown that an ideal location exists for an intermediate ring stiffener such that the axial membrane stress above this ring is circumferentially completely uniform. The ideal location of this ring is determined analytically and is expressed in terms of the basic geometric variables. This ideal ring location is then independently verified using many linear finite-element analyses. A further study explores the effect of placing the intermediate ring stiffener below the ideal location. The results are presented in a manner that makes them suitable for direct adoption into traditional design specifications. [ABSTRACT FROM AUTHOR]

Ground elevated Reinforced Concrete (RC) silo is a popular device in material handling plant and food grain processing plants to supply it throughout the year. When the structure is analyzed under wind load, the distribution of internal forces does not follow the typical pattern expected from the beam bending theory due to highly nonaxisymmetric variation of wind pressure along the circular periphery considering the silo as a thin-walled tubular structure. The silo wall deforms considerably in its cross-section due to ovalization instability. Circular silo having ratio of height of wall to diameter exceeding one (H/D>1) is susceptible to such deformation to greater extent. In the case of long cylindrical steel silo ring stiffeners are provided in order to reduce this ovalization effect on the silo wall due to wind loads. But in the case of a reinforced concrete silo, ring stiffeners are not provided to avoid construction hazards during slip forming. This paper presents a review of the previous investigations in connection with the same. In most of the investigations reviewed so far, distribution of wind pressure in cylindrical silo wall, pre-buckling and post-buckling analysis of steel silo under wind load are discussed. Little investigation has been found regarding the deformation pattern of wall of right circular cylindrical shell wall, in particular the one made up of reinforced cement concrete. The authors are deeply motivated to find a direction in this context through extensive review of work pertinent to the field and attempts will also be made in future for further improvement of the existing analysis of RC cylindrical silo wall under such action of wind load. [ABSTRACT FROM AUTHOR]

Despite owning only a couple of cattle, the landless, extreme poor can neither spare land for animal forage production nor can they afford to buy concentrate feed for their animals. In the flood-prone areas of Bangladesh, the most severe feed shortage occurs during July−October, when the low-lying pasturelands are flooded. Production, processing and preservation (silage-making) of high-yielding fodder, like Napier grass (Pennisetum purpureum), can overcome such feed shortage. Existing silage-making techniques (e.g. pit silo) are not suitable for flood-prone areas. An innovative, low-cost silage-making technology has been developed and tested in 10 flood-prone villages of Sirajganj in 2012. This portable bamboo silo (PBS) has been developed from an earlier low-cost, fixed model of Bangladesh Agricultural University. The PBS responds to the vulnerability of the extreme poor living in flood-prone areas, and their housing condition, livestock-farming capacity and ability to invest. The PBS can preserve 0.5 tonne of Napier silage, which can replace 50% need of roughage feed-rice straw of one or two local-bred cattle during 3−4 rainy months. With such feed replacement, average monthly milk production in the local cow variety increased by 12.36% (p < 0.01). Average net monthly income of the extreme poor families from selling milk also increased by 56.31% (p < 0.001) due to increased milk production and reduced feed cost. The paper also discusses general issues related to innovation for the extreme poor. [ABSTRACT FROM PUBLISHER]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A huge amount of various granular materials can be stored in and between the cells of grouped reinforced concrete cylindrical silos. The determination of design forces for reinforced concrete groups of six cylindrical silos requires significant computational effort owing to structural continuity and force transfer between adjacent silos. In this study, the efficiency of artificial neural network models in predicting the design forces and moments of groups of six cylindrical silos due to interstice loadings was investigated. Previously obtained finite-element analysis results in the literature were used to train and test the artificial neural network models. Each parameter (silo wall thickness, intersection wall thickness and the central angle spanning the intersection walls of the groups of six cylindrical silos) affecting design forces and moments was included in the input vector. The outputs of the artificial neural network models are the bending moments, hoop forces and shear forces at the supports and crowns of the interstice walls owing to interstice loadings. All artificial neural network models were trained and tested using 11 different threelayered back-propagation methods widely used in the literature. The results obtained demonstrated that all the back-propagation methods are capable of predicting the design forces and design moments at the interstice walls of the groups of six cylindrical silos. [ABSTRACT FROM AUTHOR]

The design and verification of silos resistance was comply with the Eurocodes. Stress and deformations is calculated using a global numerical analysis that used the finite element method (FEM). According to EN 1993-1-6:2008, the type of analysis performed was GMNA - geometric nonlinear analysis with material nonlinearity, where the behavior of material was nonlinear and the geometry of the structure (plate) was perfect. In accordance with EN 1991-4:2006, stresses and strains was determined for several loading hypotheses. The level of the calculated stress was assessed for the plastic limit state LS1. [ABSTRACT FROM AUTHOR]

The article discusses the architectural design of the fly ash silo with inverted cone having a height of 65 meters, constructed at a coal and biomass power plant near Rotterdam, Netherlands. INSET: SEI Data Block.

Abstract: Very few experimental installations in the world have full-scale silos, and very few assays have been conducted on them. Consequently, numerous unresolved questions remain which require further research in order to be able to reliably predict the behaviour of the material stored in these kinds of structures. In this article, we describe the design of a full-scale test station for assaying pressure in silos. The installation basically consists of a full-scale, cylindrical silo equipped with load cells to measure pressure and variable-frequency drives connected to each of the electric motors driving the filling and discharge screw conveyors, in order to study the effect on pressure of the speed at which the silo is filled or discharged. As a result of this novel design, it is possible to obtain most of the parameters which control the behaviour of stored material and to compare and validate the different theoretical models used for performing calculations and establishing current standards. The versatility of the silo design also makes it possible to adapt the geometry to the conditions which, in practice, are present most frequently in slender silos, enabling assays to be conducted for flat bottom and hopper silos, and combining both of these conditions with central and eccentric outlets. Furthermore, for each of these configurations it is also possible to study the behaviour of the material under different conditions, including static state, dynamic filling and discharge state, variations in filling and discharge speeds, pressure caused by swelling in the case of material stored when moist or saturated with aqueous solutions, and to perform simulations of an increase in silo height. [Copyright &y& Elsevier]

Abstract: Using the design described in the first of this pair of articles, a full-size silo pressure test station was constructed. In this present article, the main characteristics of this station are described, together with the results obtained from the first validation tests. In addition, these results are compared with the European standard on silos. Very few experimental installations in the world have full-scale silos, and very few assays have been conducted on them. Consequently, many uncertainties remain which require further research in order to reliably predict the behaviour of material stored in this kind of structure. The results obtained demonstrate that the theoretical design of the test station is valid for measuring silo pressures and that the station offers multiple possibilities for future research. Although the principle aim of this article is to demonstrate that the previous theoretical design is valid, some novel conclusions can also be drawn from the tests performed. For example, observation of pressure patterns under static conditions inside the silo, and of overpressure surge patterns during silo discharge, has led us to conclude that the existence of asymmetrical pressures inside the silo is not a consequence of chaotic behaviour, but rather obeys certain physical laws which have still not been sufficiently studied. [Copyright &y& Elsevier]

In the design of large and tall storage containers/structures such as silos, hoppers, and mine stopes, it is often required to determine the stresses within the container, especially at the bottom where stresses are the highest. Due to arching, where a substantial fraction of the self-weight of the granular material is carried by the wall, the vertical stress at the bottom of the container is significantly less than what is given by the product of the height and unit weight. Few analytical expressions published in the literature can be used to determine the vertical stresses taking into account the arching effect and on the basis of equilibrium considerations. The objective of this paper is to propose a new analytical method for determining the vertical stresses in a long container, assuming plane strain conditions. The method is extended to containers with rectangular and circular cross sections and is used to accommodate a surcharge at the top of the granular material. The values of vertical normal stresses computed for long-strip square, and circular cross sections are in very good agreement with those computed from Marston's theory, which was recently validated against numerical and laboratory models for providing satisfactory estimates of average vertical stresses within mine stopes. The results from the proposed model also compare well with elastoplastic numerical model results, provided K and δ are assumed to be as follows: (a) K=K0 and δ=2/3[lowercase_phi_synonym] or (b) K=Ka and δ=[lowercase_phi_synonym]. More than the expressions, the method itself would pave the way to future applications in similar and generalized problems related to storage structures with sloping walls. [ABSTRACT FROM AUTHOR]

Silage bunker runoff can be a very polluting substance and is increasingly being treated by vegetative treatment areas (VTAs), but little information exists regarding nutrient removal performance of systems receiving this wastewater. Nutrient transport through the shallow subsurface of three VTAs (i.e. one VTA at Farm WNY and two VTAs at Farm CNY) in glaciated soils containing a restrictive layer (i.e., fragipan) was assessed using a mass balance approach. At Farm WNY, the mass removal of ammonium was 63%, nitrate was 0%, and soluble reactive phosphorus (SRP) was 39%. At Farm CNY, the mass removal of ammonium was 79% in the West VTA, but nitrate and SRP increased by 200% and 533%, respectively. Mass removal of ammonium was 67% in the East VTA at Farm CNY; nitrate removal was 86% and SRP removal was 88%. The East VTA received a much higher nutrient loading, which was attributed to a malfunctioning low-flow collection apparatus within the settling basin. Results demonstrate that nutrient reduction mechanisms other than vegetative uptake can be significant within VTAs. Even though increases in nitrate mass were observed, concentrations in 1.65m deep wells indicated that groundwater impairment from leaching of nitrate was not likely. These results offer one of the first evaluations of VTAs treating silage bunker runoff, and highlight the importance of capturing concentrated low flows in VTA systems. [Copyright &y& Elsevier]

Abstract: It is known that concentric filling and discharge are the most recommended solutions in silo design. However, different reasons such as costs, space problems and the client''s specific requirements have a significant influence on the final design. Therefore, engineers sometimes need to make use of eccentric filling and discharge solutions. These designs are usually related to phenomena such as unfavorable switches in the flow regime, associated with extreme unsymmetrical pressure distributions around the silo wall, oscillations of the load, etc., which may cause failures or instabilities of silo structures, involving then high costs for the industry and, in the worst cases, accidents where human life may be endangered. Understanding about these phenomena associated with hopper eccentricities is still needed. This research work deals with pressure measurements on three steel silos with different hopper eccentricities. The results not only confirm, at a qualitative level, phenomena that have also been described in previous research, but also provide new knowledge concerning non-symmetric loads in wheat and maize silos with conical hoppers of different eccentricities. Non-symmetric components of the pressures and shifts in flow regimes have been studied and discussed in relation to load assessment for the design of silos. [Copyright &y& Elsevier]

Abstract: The flow behaviour of bulk solids depends upon a number of parameters. Shear tests are often used to determine the flow behaviour at room temperature. This paper aims to look at the influence of temperature on the flow behaviour of bulk solids. A newly developed ring shear test shows that the flow behaviour of some specific bulk solids depends upon the temperature. [Copyright &y& Elsevier]

The connection of a local support to an elevated cylindrical metal silo shell is a long-standing difficult problem in shell analysis, and most designs are based on simple ideas using past experiences of successes and failures. Smaller silo structures are often supported on local brackets attached to the side of the shell, but very few investigations of the behavior or strength of such an arrangement have ever been made. This paper presents an outline description of the behavior of a cylindrical steel shell that is discretely supported on several brackets, each rigidly connected to a stiff column or floor. The linear, materially nonlinear, geometrically nonlinear, and bifurcation behaviors of the shell under these conditions are outlined. In this problem the prebuckling deformations, bifurcation mode, and plastic collapse mode are each local. This configuration presents some interesting questions concerning the relative importance of geometric nonlinearity and geometric imperfections. The problem is recommended to advanced shell analysts as a benchmark test of their analysis and interpretation techniques. [ABSTRACT FROM AUTHOR]

Presents a new method for the construction of a steel silo that has been used in Egypt to build bolted silos with corrugated steel sheets. Method of construction; Problems encountered during construction; Evaluation of new method.

The results of the leaching of vanadium(V) from the mixture after potassium metavanadate synthesis from KCl and spent vanadium catalyst in the presence of steam were presented. Spent vanadium catalyst was obtained from the waste storage of a chemical plant producing sulfuric acid(VI) by the contact method. The reaction mixture was leached using different solutions: 1 M Na2CO3, 20% CO(NH2)2, 15% NaOH, 15% KOH, 2 M H2SO4. The effect of time and temperature was studied. The results showed that for reaction mixture leached for 4 h at 303 K in the presence of 15% sodium hydroxide solution at a liquid:solid ratio of 10:1, the extent of leaching of vanadium(V) was 95.43%. [ABSTRACT FROM AUTHOR]