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DFT functionals are of paramount importance for an accurate electronic and structural description of transition metal systems. In this work, a systematic analysis using some well‐known and commonly used DFT functionals is performed. A comparison of the structural and energetic parameters calculated with the available experimental data is made in order to find the adequate functional for an accurate description of the TiO2 bulk and surface of both anatase and rutile structures. In the absence of experimental data on the surface energy, the theoretical predictions obtained using the high‐accuracy HSE06 functional were used as a reference to compare against the surface energy values calculated with the other DFT functionals. A clear improvement in the electronic description of both anatase and rutile was observed by introducing the Hubbard U correction term to PBE, PW91, and OptPBE functionals. The OptPBE‐U4 functional was found to offer a good compromise between accurately describing the structural and electronic properties of titania. [ABSTRACT FROM AUTHOR]

Almost every branch of industry, at a certain point, utilizes omnifarous materials in their granular form. A key constituent in many bulk material logistic systems is the hopper, which usually acts as a buffering component. In order to achieve the desired throughput, the geometry of the particular hopper must be carefully determined. Considering the geometric properties of the given hopper, the inclination of the walls and the outlet orifice characteristics are the pivotal determinants of hopper functionality. In this paper, the authors have developed an analytical model of the conical hopper's mass efficiency and compared the model with the experimental results for two distinctive granular materials. The model inputs were: the density of the bulk material, critical angle of material repose, generatrix inclination angle of the cone, and diameter of the circular outlet. The experiment was conducted according to a 32 full factorial design. The repeatability of the results was examined according to Cochran's theorem and the adequacy of the data was evaluated via Fisher's criterion, which confirmed the quality of the mathematical model. The error of the developed model does not exceed 4.5%. [ABSTRACT FROM AUTHOR]

The article presents an alternative method of utilization of blast furnace slag and leachate from solid municipal waste landfills, the formation of which occurs during the infiltration of atmospheric precipitation through the thickness of deposited waste. The method is based on the conversion of leachate from the liquid phase to the solid aggregate state by lithification using blast furnace slag as an astringent material. The hydraulic activity of slag, which depends on the amount of oxides contained in it, has been estimated. The investigated slag belongs to the 3rd grade, which confirms the possibility of its use as an astringent material. The filtrate was analyzed for the content of various elements, and the maximum permissible concentrations for each element were found to be exceeded. Chemical and biological oxygen demand were determined, and critically high values were installed (17200 mgO2/l and 4750 mgO2/l, respectively). The lithification process was divided into two stages. The first stage was to reduce the organic component in the filtrate using a coagulant, aluminum sulfate; the second stage was slag hydration. The optimum ratio of lithificate components in terms of mixture solidification rate was established at 1:0.03:1.25 (leachate, coagulant, blast furnace slag). The obtained material was analyzed for the solubility and content of various forms of metal. It is established that at infiltration of atmospheric precipitations through lithificate only 3 % of material will be washed out; concentrations of gross and mobile forms of heavy metals do not exceed the maximum permissible, except for the gross content of arsenic, mobile, and water-soluble forms of which were not found. The values of chemical (687 mgO2/l) and biological (173 mgO2/l) oxygen demand in the aqueous extract from lithificate decreased more than 25 times in comparison with the initial filtrate. According to the results of toxicological studies, lithificate was assigned an IV class of waste hazard, which confirms the possibility of its use as bulk material at landfills.

Centrifugal disk dispensers are widely used in various tasks of dosing bulk, dispersed materials. The design of the disk depends on the physical and mechanical characteristics of the dosing medium. The work discusses the development of an analytical model of the movement of a material particle along a conical centrifugal disk depending on the kinematic characteristics of the dosing process and the characteristics of the dosing material, as well as experimental confirmation of the theoretical model, which is relevant for the calculation and design of working elements of this type. The obtained system of differential equations is solved using the Runge–Kutta numerical method. Experimental studies were carried out using the method of a planned factorial experiment. The experiment was conducted for three factors at three levels. The feedback criterion was the performance of a centrifugal conical disk dispenser for bulk materials. The disk cone angle was set at 10, 20, and 30°. The disk diameter was 130, 150, and 170 mm, the gap between the disk and the edge of the hopper neck was 6, 8, and 10 mm, and the rotational speed of the conical disk was 0.65, 1.02, and 1.39 rad/s. The dispensing rate of the dispenser ranged from 15 to 770 g/s, depending on the values of the experimental factors. For use in the regression equation of the natural values of the factors, a method of transforming the terms of the equation from coded values to natural ones is provided. The obtained experimental correlation dependencies were checked for reproducibility with Cochrane's test, and the adequacy of the model was checked using Fisher's test. The significance of the coefficients in the correlation equation was evaluated using the Student's t-test. The difference between the experimental data and the results of the theoretical modeling does not exceed 5%. The obtained system of differential equations makes it possible to model the radial velocity of the ascent of bulk material from the conical rotating disk depending on the rotation frequency, disk diameter, and the height of the annular gap between the discharge throat of the hopper and the conical disk. The analytical model enables the modeling of the productivity of the conical dispenser for bulk materials for arbitrary parameters of rotation frequency, disk diameter, and the size of the annular gap between the discharge throat of the hopper and the conical disk. [ABSTRACT FROM AUTHOR]

The logistics network is considered the provider of logistics activities in supply chains. The fluctuating requirements of customers and the logistics network's complex structure are only a few of the factors that cause challenges to its management. Industrial facilities are particularly vulnerable to challenges because material handling operations dominate in addition to manufacturing activities. Disruptions at industrial plants are disseminated through the logistics network, affecting all supply chain participants. As a result, reducing material handling time and costs to decrease material losses, pollution, and productivity is vital to their business. Due to their distinctive properties and significant share in finished goods, bulk materials are particularly vulnerable to issues during manufacturing. Accordingly, this study aims to rank and select technologies for handling bulk materials in an industrial plant where the production of construction materials is performed. This paper proposes four alternative solutions for the observed case study, and nine criteria were selected for the evaluation. A new hybrid multi-criteria decision-making model is proposed. The model combines Fuzzy Step-Wise Weight Assessment Ratio Analysis (SWARA), used to determine the weight of criteria, and the Axial-Distance-Based Aggregated Measurement (ADAM) method, used to rank alternative solutions. The model results indicate that the pneumatic conveyor is the best ranked alternative that significantly increases productivity, reduces losses, and improves working conditions. The key contributions of this study are its analysis of the efficiency of the technologies proposed for bulk material handling and the development and implementation of a model framework for the ranking of these technologies. [ABSTRACT FROM AUTHOR]

Almost every branch of industry, at a certain point, utilizes omnifarous materials in their granular form. A key constituent in many bulk material logistic systems is the hopper, which usually acts as a buffering component. In order to achieve the desired throughput, the geometry of the particular hopper must be carefully determined. Considering the geometric properties of the given hopper, the inclination of the walls and the outlet orifice characteristics are the pivotal determinants of hopper functionality. In this paper, the authors have developed an analytical model of the conical hopper’s mass efficiency and compared the model with the experimental results for two distinctive granular materials. The model inputs were: the density of the bulk material, critical angle of material repose, generatrix inclination angle of the cone, and diameter of the circular outlet. The experiment was conducted according to a 32 full factorial design. The repeatability of the results was examined according to Cochran’s theorem and the adequacy of the data was evaluated via Fisher’s criterion, which confirmed the quality of the mathematical model. The error of the developed model does not exceed 4.5%.

Relevance. The search for a useful application of carbonaceous residues of rice husks thermal processing. These residues due to high silicon content in the inorganic part can potentially be used to produce silicon carbide – an important functional material for various fields of science and technology. Useful utilization of this waste will allow not only solving the environmental problem associated with their inefficient application and formal disposal, but also obtaining value-added products in the form of SiC-based ceramics. Aim. To obtain SiC-based bulk products from carbonaceous residues of rice husk thermal processing by spark plasma sintering with a minimum number of additional stages of feedstock processing. Objects. SiC-based bulk products obtained using carbonaceous residues of rice husk thermal processing. The samples were obtained by spark plasma sintering at 1800 °C, pressure of 60 MPa and holding time of 10 minutes. Methods. Spark plasma sintering; X-ray diffractometry (X-ray phase analysis); scanning electron microscopy; vacuumless arc discharge synthesis method. Results. The authors have carried out the experimental studies to assess the possibility of applying carbonaceous residue of rice husk thermal processing as a precursor for the synthesis of silicon carbide in bulk (ceramics) and dispersed (powder) forms. A series of experiments on spark plasma sintering of carbonaceous residue from rice husk thermal processing in the initial and milled form, with SiO2 silica sand additives, as well as with the use of silicon carbide powders synthesized from carbonaceous residue by vacuumless arc discharge method were implemented. The latter is performed within a one-stage fast-flowing process in an air environment and does not require the use of a vacuum system. Preliminary results demonstrated the possibility of obtaining bulk products and dispersed powders based on silicon carbide with a content of at least 50 and 60 wt %, respectively, and indicate the prospects of further increasing phase purity by optimizing spark plasma sintering and vacuumless arc discharge synthesis.

Friction parameters such as the angle of internal friction and the external friction of soils (bulk materials) show the possibilities of further material use. These are, for example, possibilities for soil processing, handling, and storage. The determination of friction parameters is usually carried out under laboratory conditions. For the possibility of determining the properties of soils outside the laboratory in terms of immediate material response, a laboratory prototype was developed. The main objective for its development was to determine the effect of the shape of the friction surface when "sliding" on the soil. This was achieved with the help of validation equipment designed to measure, test, and validate the processes of raking, material piling, material transfer and removal, and tool movement or sliding on or in a material. It was found that by using an appropriate speed and normal load, the Jenike method can be applied to determine the angle of external friction over a shorter distance with an error of about 6–7.5% from the values measured on a calibrated shear machine. The results also showed that the method can be applied to detect the shear stresses that arise when a tool is plunged into a material, and thus predict the possible increase in energy loss during the process. [ABSTRACT FROM AUTHOR]

The processes of material capture and movement in a screw feeder are characterized by significant loads due to the pressure of a vertical load column, which creates additional resistance to the movement of the material, overcoming which leads to unproductive energy consumption. The paper aims to study the influence of the design parameters of the loading mechanism on the torque on the drive shaft of a screw feeder. The results of experimental studies and computer simulation of the design parameters of the loading mechanism relation (the length of the loading zone, the inclination angle of the rotating wall of the loading nozzle, its displacement value relative to the vertical axis of the auger operating part, and the height of the material in the loading nozzle), to the torque value on the drive shaft of the screw feeder for transportation of bulk cargo, are presented in this paper. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental studies conducted with the aim of determining the characteristics of the heat exchange of a dense layer of bulk material with surfaces and obtaining empirical dependences for average and local heat transfer coefficients during transverse flow through a dense layer of a submerged cylinder. Empirical dependences are valid in a wide range of changes in geometric and regime parameters within a satisfactory experimental error. The need for research in this area is due to the fact that most of the known literature data on heat exchange between dispersed material and the surface describes heat exchange with flows at a low concentration of dispersed material (dusty flows, gas suspension, fluidized beds). The heat exchange of a dense layer with a surface is devoted to a rather limited number of works carried out in the seventies and eighties, but even in these works there are contradictions not only of a quantitative, but also of a qualitative nature. In the presented work, the research was carried out on an experimental installation, made in the form of a rectangular vertical mine, in which, under the action of gravity, bulk material enters in the form of a dense layer. Determination of heat transfer coefficients was performed using the methods of stationary and regular thermal regimes. As a result of the generalization of experimental data, criterial dependences were obtained, which allow thermal calculation of tubular heat exchangers for heating (cooling) bulk materials moving in the form of a dense layer. The resulting dependencies are important for the chemical industry, at non-ferrous metallurgy enterprises, during heat treatment of materials and in other industries where there is a need to heat (cool) bulk materials in the relevant technological processes or for the purpose of heat utilization. [ABSTRACT FROM AUTHOR]

A design of a continuous mixer is proposed for implementation of an ordered loading of the mixture components into a circulating mixer. A mathematical model is developed for the preparation of a three-component mixture to adjust the loading process of the key component, which is most prone to segregation, into the mixer. Due to the patented design of a classifier, radial blades can be installed inside the drum to neutralize the negative effect of segregation. The results of numerical experiments make it possible to determine the cross section of a classifier, under which the efficiency of separating particles of fine and commercial fractions from the mixture decreases. In this section of the classifier, the radial blade should be installed. The use of mathematical models based on Markov chains is also possible for other types of devices with an ordered movement of the components of a mixture of bulk materials. [ABSTRACT FROM AUTHOR]

Rock crushing plants cannot afford unforeseen breakdowns with the current boom in the construction sector. This paper discusses measures that can be used to predict wear on chutes in the plant so that predictive maintenance can be implemented. Some of the chutes used to transfer the materials are difficult to access. Failures of the chutes cause downtimes, which are untimely and costly. The objective of this research is to determine the wear rates of chutes. A chute system was designed, modelled and validated using the Solidworks® software and then imported into the EDEM® software to predict the failure of the chutes. Factors affecting the abrasion wear of the metal were determined and used as input parameters to perform a simulation on EDEM® to validate the wear recorded. The service life obtained for mild steel S275 was 731 hours and that of abrasion resistant steel Hardox® 400 was 1490 hours, and it was deduced that the difference in the value of hardness of the metals to that of the rocks they carry significantly affects the wear of the chutes. The software was also used to replicate the flow of boulders on chutes and an accelerated flow rate of 496 tons per hour (t/h) was achieved at an angle of elevation of 24.4°.

The processes of material capture and movement in a screw feeder are characterized by significant loads due to the pressure of a vertical load column, which creates additional resistance to the movement of the material, overcoming which leads to unproductive energy consumption. The paper aims to study the influence of the design parameters of the loading mechanism on the torque on the drive shaft of a screw feeder. The results of experimental studies and computer simulation of the design parameters of the loading mechanism relation (the length of the loading zone, the inclination angle of the rotating wall of the loading nozzle, its displacement value relative to the vertical axis of the auger operating part, and the height of the material in the loading nozzle), to the torque value on the drive shaft of the screw feeder for transportation of bulk cargo, are presented in this paper.

Grain security is an important guarantee for sustainable development. However, the dynamic behavior of silos containing grain-like material is not well understood. The effective mass and dynamic effects are the key parameters for the assessment of the silo–bulk material system during earthquakes. Herein, on the basis of the Janssen continuum model, it is proposed that the seismic energy is entirely dissipated by the interactions between the materials and the silo and the materials themselves. The seismic inertia forces among storage materials were introduced, and dynamic equilibrium equations considering the vibrations of storage materials were established. Theoretical solutions for the horizontal forces exerted and the effective mass of the silo–bulk material system during earthquakes are proposed. It is worth noting that the additional stress on the side wall proposed in this work is related to the depth, silo radius, storage density, internal friction coefficient, lateral pressure coefficient, and seismic acceleration. In addition, the effective mass coefficient is negatively correlated with the external friction coefficient, the lateral pressure coefficient, and horizontal seismic acceleration under a storage vibration state. A narrower silo (i.e., with a larger height–diameter ratio) has a low effective mass coefficient. The results from our method are in good agreement with those attained using experimental data, which demonstrates the accuracy and universality of the proposed formulations. [ABSTRACT FROM AUTHOR]

The logistics network is considered the provider of logistics activities in supply chains. The fluctuating requirements of customers and the logistics network’s complex structure are only a few of the factors that cause challenges to its management. Industrial facilities are particularly vulnerable to challenges because material handling operations dominate in addition to manufacturing activities. Disruptions at industrial plants are disseminated through the logistics network, affecting all supply chain participants. As a result, reducing material handling time and costs to decrease material losses, pollution, and productivity is vital to their business. Due to their distinctive properties and significant share in finished goods, bulk materials are particularly vulnerable to issues during manufacturing. Accordingly, this study aims to rank and select technologies for handling bulk materials in an industrial plant where the production of construction materials is performed. This paper proposes four alternative solutions for the observed case study, and nine criteria were selected for the evaluation. A new hybrid multi-criteria decision-making model is proposed. The model combines Fuzzy Step-Wise Weight Assessment Ratio Analysis (SWARA), used to determine the weight of criteria, and the Axial-Distance-Based Aggregated Measurement (ADAM) method, used to rank alternative solutions. The model results indicate that the pneumatic conveyor is the best ranked alternative that significantly increases productivity, reduces losses, and improves working conditions. The key contributions of this study are its analysis of the efficiency of the technologies proposed for bulk material handling and the development and implementation of a model framework for the ranking of these technologies.

When using complex spatial patterns for transportation, the straight screw conveyors have a series of obvious disadvantages. This paper presents a design of a flexible screw sectional working body that allows increasing the functional and operational characteristics of screw conveyors used in the transportation of bulk agricultural materials. A mathematical model of the dynamic system of a flexible screw conveyor has been established, and dynamic starting torques have been calculated at the rated load of loaded screw, and when the system is braking. Analysis of the results obtained shows that, with significant damping coefficients, the start-up transition process occurs smoothly, and the load reaches its rated value without torque and speed fluctuations. It has been established that fast braking significantly increases the dynamic loads that may exceed the maximum critical torque of the electric motor (by 50–70% on average) and the rated load torque (by 2.5–3 times).

The simulation of mass motion using a vibrating device that was laboratory designed was the main idea of the work. The construction of an experimental vibrating device and the associated measuring station along with the measurement of dynamic properties of the vibrating device depending on preselected input parameters of the device of bulk material on this experimental model is presented. The simulation of the general behavior of particles on an experimental vibrating device at rotational frequencies of 20 Hz, 25 Hz and 35 Hz, and the rotation of contact vibrators at 30°, 45° and 75° by mass flow modeling using software ROCKY DEM is done. It was observed that the particles were moving at the fastest speed at 45° and at 35 Hz and that the top layers fall to the bottom especially at higher rotational frequencies, which may ultimately cause aeration of the particulate matter, thus reducing the angle of internal friction of the bulk material. [ABSTRACT FROM AUTHOR]

We predicted a new kind of carbon allotrope T6, which is composed of pure non-coplanar pentagon carbon atoms ring. We calculated its phonon dispersion which shows that the structure is stable. The physical properties, such as band structures, elastic tensors and thermal conductivity tensors, are calculated and compared with the diamond and the tetragonal crystal structure of carbon (T12C). [Display omitted] • A new structure of bulk carbon allotrope is predicted by using density functional theory (DFT). • It is constructed by pure pentagon carbon atoms rings. • The five Raman active modes are got. • The helical polarization Raman spectroscopies are calculated. • Physical properties (band structures, elastic tensors and thermal conductivity tensors) are got and compared with the diamond and the tetragonal crystal structure of carbon (T12C). Based on the density functional theory (DFT) computing method, a kind of bulk carbon allotrope consisting of non-coplanar pentagon carbon atom rings was predicted. The helical polarization Raman spectroscopies are got by numerical calculation. The physical properties, such as band structures, elastic tensors and thermal conductivity tensors, are calculated and compared with the diamond and the tetragonal crystal structure of carbon (T12C). [ABSTRACT FROM AUTHOR]

The relevance of this study lies in the need to improve, develop innovative designs, and determine the best structural and kinematic parameters of the hinged sections of the screw working bodies of the conveyors, to obtain better functional and operational characteristics in transporting bulk and lumpy materials and granular fertilizers. Therefore, the purpose of this study was to improve the performance of flexible screw conveyors by developing and determining the best parameters of hinged flexible screw sectional working bodies for transloading bulk materials along curvilinear transportation branches. The study was conducted using the methods of the theory of mathematical and computer modelling, the method of mathematical planning of the experiment. The paper presents innovative designs of hinged screw working bodies and substantiates their best parameters for ensuring the movement of bulk materials along curvilinear routes. The study found the correlation between the magnitude of the torque that occurs between the loaded screw sections and their spatial arrangement. Analytical dependences were obtained for the stiffness conditions of a separate section with a hinged connection, depending on the load and design parameters of the conveyor. It was found that the angular displacement of the sections according to the state of dependence helps to significantly (up to 4-5 times) reduce the amplitude of the change in the torque of the drive and lowers its maximum value. It was proved that in the pushing mode, energy consumption is 1.06...1.4 times higher than in the pulling mode. The practical significance of the results lies in the ability to choose the optimal structural, kinematic, and technological parameters of the developed sections of the screw working body for transporting bulk or lumpy materials and mineral fertilizers. [ABSTRACT FROM AUTHOR]

Handling bulk material is specific and has different needs than handling piece goods. Bulk material requires a space that is adapted to both filling and emptying of such type of material. It is necessary to dimension the storage tanks in order to ensure an efficient production process. Emptying the storage tank also depends on the transportation of the bulk material to the production process. Road transport trucks must be adapted to transport bulk material, and the vehicle's capacity is the most important for emptying. In addition, it is necessary to monitor the performance of the filling equipment and the emptying technology. In terms of labour input, this process can be effectively monitored with the help of simulation. The simulation model, created in the ExtendSim 10 program, graphically displays various options for setting the emptying process parameters. [ABSTRACT FROM AUTHOR]

A mathematical model of a cascade separator with two or several initial material inputs into the apparatus is developed. We can significantly affect the compositions of final products by feeding material to various stages of the cascade. It is very important for processes whose objective is to obtain powders with specified compositions. By way of example, we can mention copper powders for aircraft and motor-cars industries. The requirements for such powders include limitations on the contents of three different fractions within the total range of powder sizes. Since the sizes of these fractions are much below 100 microns, it is practically impossible to separate them using sieves for further preparation of required compositions on an industrial scale. However, this problem is solved by separation methods by dividing the initial material between two inputs into the apparatus. It is practically impossible to solve this problem empirically. We have managed to do it using the mathematical model described in the present paper. [ABSTRACT FROM AUTHOR]

AbstractNanocomposites, a high-performance material, showcase uncommon asset combos and precise layout possibilities. Their versatility is so compelling that they can be of use in many countries, spanning from packaging to medical purposes. In this comprehensive evaluation, the three varieties of matrix nanocomposites are presented, demonstrating the use of such compounds, their optimization techniques, and a few latest consequences on structure, parameters, and potential programs. The parameters of nanoparticles are rapidly changing in accordance with their grain size equivalents. Furthermore, it modifies the manner in which molecules are hooked up to grain materials. As a consequence, the materials are often changed repeatedly with respect to the elements. A few other nanocomposite products have been shown to be 1,000 times tougher than most of the elements. This is necessary to understand the existence and usage of nanocomposite substances and examine components, functions, and innovative attributes in polymer, ceramic, and metallic nanocomposites. It is deduced by taking a quick glance at technological and biochemical applications. It can be seen that polymer nanocomposites and eventually the chemicals are used mostly in their processing and find applications in various industries, including aviation, the defense industry, food, and electronic components, attributable to their heavier mechanical, electrical, and thermal properties. This chapter forms the basis for and takes an approach to the emerging field of nanocomposite technology as it relates to biofuel production and its implementation.

Optical superlattice is a nonlinear optical material based on the quasi phase matching technology. Optical superlattice with different microstructures enabled by ferroelectric domain engineering can efficiently and flexibly realize nonlinear frequency conversions as well as multi-dimensional manipulation of the light field. The host material of optical superlattice has been undergoing the development from bulk to thin film. With the breakthrough of the fabrication techniques of the two material platforms, diverse important applications have been spawned, such as laser frequency conversion technology, nonlinear light field manipulation and multi-functional integrated photonic chips. [ABSTRACT FROM AUTHOR]

The object of this study is the process of impregnation of liquid into the bulk material, in particular, into the soil. Determining the impregnation parameters is a relevant task when assessing the consequences of an emergency spill of a hazardous liquid. Infiltration of liquid into the soil leads to pollution of water resources. However, the greatest danger is the ignition of the spill of a combustible liquid. Based on the Green-Ampt model, a mathematical description of the impregnation of liquid into bulk material was built. It is a system of two ordinary differential equations of the first order, one of which describes the reduction of the thickness of the liquid layer on the surface, and the other describes the dynamics of the impregnation of liquid into depth. The solution to the system was derived in the form of time dependence on the depth of impregnation. An experimental study was conducted on the example of impregnation of crude oil in the sand. To this end, sand was poured into a vertical measuring glass cylinder. After that, the liquid was poured and a video recording of the impregnation process was carried out. By processing the video recording, the depth of impregnation and the corresponding time were determined. The results of the study show that the relationship between the thickness of the liquid layer on the surface of the sand and the depth of impregnation is linear in nature: the relative deviation of linear approximation from experimental data does not exceed 3.5. By expanding the logarithmic function contained in the solution to the system of differential equations into the Taylor series, a polynomial dependence of time on the depth of impregnation was established. To determine the coefficients of the polynomial based on the experimental data, the least squares method was used. In this case, the approximation error after the first minute after spilling does not exceed 10 %. The proposed method could be used to account for seepage in the model of liquid spreading on the ground and the burning model of a flammable liquid spill [ABSTRACT FROM AUTHOR]

Storage is one of the primary activities of manufacturing enterprises. Mainly, enterprises deal with the storage of piece materials, but there are also production processes using bulk materials. For this material, enterprises need to create specific storage areas - buffers. The first activity before creating a buffer is determining the nature of its filling and emptying, which affect the main parameter of buffers, namely capacity. Specifically, it is necessary to know the hourly performance of the filling equipment, the method and speed of emptying, and the type and capacity of the means of transport into which the material is loaded. The simulation software brings a modern touch to the years-proven procedures for determining the capacity of bulk material buffers and speeds up the process. In the paper, simulation replaces the previous approaches to creating graphic outputs, which check the mathematical part of the algorithm and visualize the behaviour of the buffer in specific situations. The result of the use of simulation is the rapid creation of graphs of material supply and easy checking of several options through experimentation with the simulation model. [ABSTRACT FROM AUTHOR]

Hoppers for unloading bulk materials are an indispensable feature of many technological machines and not only those employed in agricultural production. One of the problems in the operation of hoppers is the appearance of dynamic arches which make the outflow of grain uneven. Experimental studies have previously shown that the formation of dynamic arches creates an uneven outflow of grain along the vertical zones of outlet hoppers. This can lead to the processing mode violation of bulk material and loss of machine productivity. This paper theoretically shows that the use of arch-breaking devices with an element oscillating in the grain layer requires systems for automatic adjustment of oscillation frequency. This complicates the design and makes it more expensive. It is proposed to amend the type of material outflow as it moves along the hopper's height to solve this problem. The possibility of employing this approach has been tested on the use of a bulk material flow separator in the outlet hopper. The bulk material flow separator is made in a plate form and is installed rigidly between two opposite walls of the outlet hopper. Thus, the volume of the hopper is divided into two vertical equal parts. With the help of experimental studies, it was determined that the lower side of the bulk material flow separator should be at a distance of 0.3 of the total hopper height from the discharge opening, while the upper side of the separator should be at a distance of 0.25 of the hopper's height from the top edge of the hopper. The experimental verification of flow separator use confirmed its effectiveness. [ABSTRACT FROM AUTHOR]

The Integrated Offshore Standard Specification (IOSS) involves Korean shipyards, classification societies, research institutes, the Korean industrial society, engineering companies, and oil companies with the objective of reducing costs and risks without compromising safety in international offshore engineering procurement construction (EPC) projects using new standardized bulk components and qualification procedures. The activities of the IOSS include the analysis of the existing rules and regulations to achieve the best standardization, which is reflected in the best practices, and minimize the variables in regulations and rules. In addition, a standard inventory of shapes and dimensions, referred to as specifications, is proposed in the IOSS. In this paper, the aluminum tertiary standardization part (IOSS S102-1/2 S104: Specification for Structural Tertiary Design) is presented with the details of the procedures, background reviews, and cost-benefit analyses of the design and verification methods for standard designs in the IOSS standardization items. Based on the cost-benefit analysis, the application of standardized aluminum tertiary items to offshore projects has significant advantages in terms of maintenance and repair compared to the carbon steel tertiary items utilized in current industrial practices.

Estimating the need for instrumentation bulk material which can amount to thousands of items, is a job that requires much effort, especially in the short tender phase. This situation becomes critical when faced with dynamic project needs where no single project needs precisely the same process control. The engineer concerned is always required to use his technical knowledge in selecting the appropriate hook-up type before bulk material estimation can be made. Easy Hook-up is a digital solution that makes bulk material estimation activity more accurate, efficient, and cost-effective. Easy Hook-up can save man-hours up to 93.3%. [ABSTRACT FROM AUTHOR]

Nanocomposites, a high-performance material, showcase uncommon asset combos and precise layout possibilities. Their versatility is so compelling that they can be of use in many countries, spanning from packaging to medical pur- poses. In this comprehensive evaluation, the three varieties of matrix nanocompo- sites are presented, demonstrating the use of such compounds, their optimization techniques, and a few latest consequences on structure, parameters, and potential programs. The parameters of nanoparticles are rapidly changing in accordance with their grain size equivalents. Furthermore, it modifies the manner in which molecules are hooked up to grain materials. As a consequence, the materials are often changed repeatedly with respect to the elements. A few other nanocomposite products have been shown to be 1,000 times tougher than most of the elements. This is necessary to understand the existence and usage of nanocomposite sub- stances and examine components, functions, and innovative attributes in polymer, ceramic, and metallic nanocomposites. It is deduced by taking a quick glance at technological and biochemical applications. It can be seen that polymer nano- composites and eventually the chemicals are used mostly in their processing and find applications in various industries, including aviation, the defense industry, food, and electronic components, attributable to their heavier mechanical, electrical, and thermal properties. This chapter forms the basis for and takes an approach to the emerging field of nanocomposite technology as it relates to biofuel production and its implementation. [ABSTRACT FROM AUTHOR]

A design of a classifier with coaxially placed pipes wherein a structured swirl flow is formed, which enables separation of particles of a fixed size from gas with 65–75 % efficiency, is proposed. With decrease of design dimensions of the classifier the separation boundary of the bulk material shifts toward smaller size ranges. Best results are obtained if the width of the rectangular slots in the internal pipe of the classifier is 10 mm because at this width the bulk material is separated in the classifier with practically no change of efficiency. Pressure loss in the classifier with coaxially placed pipes ranges from 110 to 405 Pa if the height of the rectangular slot is reduced from 30 to 10 mm and its width is reduced from 10 to 3 mm. [ABSTRACT FROM AUTHOR]

The microstructural properties and thermodynamic parameters before and after abrasion were examined for a bulk Cu86Al10Ta4 (%wt.) shape memory alloy produced by the arc-melting method. From the XRD and SEM–EDX microstructural analysis, it was found that the alloy provided α (Cu), γ 1 (Cu9Al4), γ 1 ′ (2 H) , β 1 ′ (18 R) , and Ta2Al3 phases before wear, while, after abrasion, depth grooves, wear debris, and ridges and delamination structures were observed. In the forward phase transformation, the DSC result displayed a single narrow peak, which represented β 1 → γ 1 ′ , which for the reverse martensitic phase transformation the peak was wide and displayed γ 1 ′ → β 1 . It was observed that the volume and mass losses, friction coefficient, wear coefficient, and wear rates are affected by changing the distance and applying load. The value of phase transformation temperatures, enthalpy, entropy, Gibbs free energy, and elastic energy of the bulk material changed after abrasion. Moreover, the post wear alloy exhibited shape memory behavior in both the heating and cooling processes. [ABSTRACT FROM AUTHOR]

When bulk materials are subjected to stress, the energy input releases particles, which disperse in the air. This is an effect that has to be avoided for both process‐related and safety reasons. Therefore, the research project described here deals with the development of a method for the prediction of dust emissions during processes handling bulk materials. It is based on an experimental and concurrently on a numerical level. The calculation of dust emissions in advance allows for implementation of necessary measures before the construction and operation of a plant processing bulk materials. [ABSTRACT FROM AUTHOR]

This article focuses on the experimental verification of a mathematical derivation of Janssen’s theory, which describes the distribution of pressures within the bulk material and pressure distribution on the walls of storage facilities. The experimental verification is performed in two ways. The first is the real measurement of the load transfer in a bulk material cylinder and the second is similar to the detection of the load transfer through simulations using the DEM method. The aim is to compare the results of the theoretical calculation according to Janssen’s theory with the real measurement and a simulation of exactly the same model situation. At the beginning of any design or optimisation of existing transport or storage facilities, the most important is the analysis of the bulk material in the form of measurements of mechanical-physical properties. The analysis methods used are also described here. The pressure at the bottom of a storage container between the methods used showed negligible differences. From this finding, it can be concluded that the DEM method is a very suitable means for verifying the design of transport and storage facilities. The simulations provide important information and insights that can also be used to optimise existing transport or storage facilities.

Concept of bulk material and complexity of storing it are explained. The dependence between the physical and mechanical properties of the loose material and type of construction in which it is stored. Structural elements considered silos and silos with conical and flat bottom are described. The common characteristics of metal silos for bulk materials are given. The classification of metal silos by type of housing design is given. The advantages and disadvantages of silos are described. The possibility of storage of bulk materials in cylindrical shells is analyzed depending on the type of construction. The history of occurrence of structures of spiral-fold silos is considered. The set of equipment for the construction of the housing of the spiral-fold silos is given, the step-by-step process of formation of the folding lock and features of the installation process are presented. The analysis of the structure is made and the advantages and disadvantages of spiral-fold silos are determined.

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The paper describes the problem of designing screw conveyors in terms of determining their exploitation characteristics. Based on the actual values of mass efficiency and power demand obtained in a laboratory experiment, the theoretical design methods and the numerical discrete element method model results were verified. The obtained results have shown that the currently used theoretical methods underestimate the mass efficiency and power demand compared to experiments when typical values of filling rate coefficient and progress resistance coefficient are used. It was also shown that the results of DEM simulations are in good agreement with the experiments in terms of mass efficiency and power demand. Based on the exploitation characteristics determined in DEM simulations for different constructions of the screw and different rotational speeds, multi-objective optimization of the exploitation parameters of the screw was performed in order to minimize the power demand of a screw conveyor and simultaneously maximize its mass efficiency. The optimization results showed that it is possible to find such construction and the rotational speed that will maximize the mass efficiency of the conveyor and keep the power demand low, reducing the exploitation costs of the device. [ABSTRACT FROM AUTHOR]

Industrial bulk material transfer and handling processes often cause large amounts of dust emission and seriously threatens workers' health. Proper design of dust removal system requires an understanding of the volume flow rate of entrained air during the falling process of the particle plume. Based on previous researches, this paper deduces the formula of the volume flow rate of entrained air through theoretical analysis. This theoretical formula involves the initial velocity of the particles and the void fraction of particle plume core zone. By comparing with former experimental and numerical calculation results, it is found that the theoretical formula can better predict the volume flow rate of entrained air. The numerical calculation is used to analyze the influence of the initial velocity of the particles and the angle of the particle source on the volume flow rate of entrained air. It was found that when the initial velocity of the particles increased from 0.1 m/s to 10 m/s, the volume flow rate of entrained air is hardly affected during the falling process. The angle between the particle source and the horizontal direction has a greater influence on the total volume flow rate of entrained air. With the angle of particle source between 30° and 45°, the total volume flow rate of entrained air is the largest for different drop height. [ABSTRACT FROM AUTHOR]

Molybdenum nitrides (MoNs) are important materials for their excellent physical and chemical properties, but synthesizing stoichiometric and bulk materials is still a great challenge. In this paper, a new method to prepare bulk molybdenum nitrides was proposed. A novel method based on an untraditional in situ gaseous nitrides under high pressure is developed. In the synthesizing, the sandwiched structure with metal pellet core inside and two pellets of solid nitrogen source outside was used to synthesize bulk molybdenum nitrides. Cubic structured MoN (c-MoN) and hexagonal structured MoN (p-MoN) are synthesized at high pressure and high temperature (HPHT) using molybdenum and melamine as precursors. In both as-synthesized nitrides, p-MoN has an excellent Vickers hardness (Hv) of 29 GPa under a relative low load, which is much harder than that of TiN under the same applied load of 0.49 N. The asymptotic hardness of p-MoN approaches to that of WC (~22 GPa), which is widely used as a hard material. This method not only helps us to find new phase of transition metal nitrides but also provides an useful way for synthesizing high quality bulk transition metal nitrides.

Hoppers for unloading bulk materials are an indispensable feature of many technological machines and not only those employed in agricultural production. One of the problems in the operation of hoppers is the appearance of dynamic arches which make the outflow of grain uneven. Experimental studies have previously shown that the formation of dynamic arches creates an uneven outflow of grain along the vertical zones of outlet hoppers. This can lead to the processing mode violation of bulk material and loss of machine productivity. This paper theoretically shows that the use of arch-breaking devices with an element oscillating in the grain layer requires systems for automatic adjustment of oscillation frequency. This complicates the design and makes it more expensive. It is proposed to amend the type of material outflow as it moves along the hopper’s height to solve this problem. The possibility of employing this approach has been tested on the use of a bulk material flow separator in the outlet hopper. The bulk material flow separator is made in a plate form and is installed rigidly between two opposite walls of the outlet hopper. Thus, the volume of the hopper is divided into two vertical equal parts. With the help of experimental studies, it was determined that the lower side of the bulk material flow separator should be at a distance of 0.3 of the total hopper height from the discharge opening, while the upper side of the separator should be at a distance of 0.25 of the hopper’s height from the top edge of the hopper. The experimental verification of flow separator use confirmed its effectiveness.

The problem on pressure distribution in the bulk material of the round silo with allowance for viscous fluid with dry internal friction is considered.

The paper discusses the designing process of screw conveyors, with regard to the determination of the exploitation parameters of such devices with the use of the Discrete Element Method (DEM). The influence of the chosen model input parameters on the results of the simulations was examined. The key parameters which determine the exploitation characteristics of a screw conveyor were identified as follows: the size of a DEM particle, coefficients of internal and external friction. Experimental measurements of the laboratory screw conveyor provided the actual exploitation characteristics of a device used for the transportation of a limestone powder. The comparison of the results of the simulations and experiments gave satisfactory results. For this reason, DEM simulations were identified as an effective tool for determining and optimization of the construction and exploitation parameters of the screw conveyors. [ABSTRACT FROM AUTHOR]

Purpose. Creation of mathematical models that allow determining the relationship between the design and technological parameters of the plate feeders and the energy consumption arising during their operation. Methodology. The work uses the classical mechanics principles, the contact interaction of solids theory and the mathematical modeling method. Findings. The paper considers the design and operation principle of a continuous plate feeder, defines its main design and technological parameters. The factors that create mechanical loads on the drive of the feeder plate are investigated. Mathematical models have been developed that make it possible to determine the moments of resistance and the power consumed by an electric motor during the equipment operation. The proposed models make it possible to determine the load on the drive in static and dynamic operation modes and take into account the design, technological parameters of the equipment and the bulk material physical and mechanical properties. The study results of the friction coefficients influence, the knife position and the force of its pressing on the plate surface, the plate rotation speed on the loads acting on the electric drive are presented. It has been found that the drive calculation is expedient for the mode in which the distance between the knife edge and the rotation axis of the plate is maximum, which corresponds to the operation at maximum load. It has been determined that a change in the feeder technological parameters (plate rotation speed, knife position) can lead to a change in the load on the electric drive by 86%, which must be taken into account when choosing a drive. Originality. Mathematical models of the continuous plate feeder operation have been developed, which make it possible to determine the relationship between the design and technological parameters of the plate feeders and energy consumption. Practical value. The results obtained make it possible to determine the load on the plate drive by the known design, technological parameters and bulk material physical and mechanical properties. [ABSTRACT FROM AUTHOR]

Moisture migration in bulk materials can cause many problems for bulk material handling. The review aims to find an appropriate method for dynamic moisture migration in unsaturated bulk materials during processing. A large amount of research on moisture migration has been done from both macroscopic and microscopic views. From the macroscopic view, moisture migration in bulk materials such as soil, sand, and grain, were relatively well understood based on the diffusion theory and infiltration theories. The microscopic theory, liquid bridge rupture, and vibration were also well developed. The theories and simulation models can be widely used in geotechnology, food engineering and process control of bulk material. However, current research concerns little about dynamic moisture migration in unsaturated bulk material. Some further development of theories and simulation models are needed. [ABSTRACT FROM AUTHOR]