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•Olive leaves were dried in a conveyor belt dryer aimed at supercritical extraction.•Influence of drying conditions on extraction was investigated.•Leaf temperature and output ...moisture were successfully predicted by a drying model.•Higher extraction yields and AA were found in samples dried at 50 °C for 300 min.•Total phenolic compounds content was enhanced in samples dried at 70 °C for 60 min.
The influence of drying conditions on the composition of supercritical extracts recovered from olive leaves was investigated. Leaves were dried on a conveyor belt and the effects of air temperature and residence time on the extraction kinetics, global yield, antioxidant activity, total polyphenols content and chemical profiles of the extracts were evaluated. Inlet air temperatures of 50, 60 and 70 °C with residence times of 180, 120 and 60 min, respectively were tested. A model based on mass and energy balances with effective heat and mass transfer coefficients fitted from experimental data was used to describe the drying process. The temperature and output moisture of the leaves were well predicted by the model. The extraction kinetics was not significantly affected by the drying conditions (air temperature and residence time), but the extraction yield was enhanced for samples dried at 50 °C/180 min whereas the higher values of antioxidant activity and phenolic contents were found at 60 °C/120 min. Sovová’s model was effective in describing the supercritical extraction of olive leaves and can be used to estimate the extraction kinetics and mass transfer coefficients.
The transfer points between conveyors are crucial elements of the infrastructure that determine the capacity of the transport system. The correct design of the ore transfers determines the steady and ...stable feed of the material to the receiving conveyor. Branch conveyors transporting material before the pre-crushing stage are exposed to blockages caused by a large fragment of ore or other elements (pieces of wood or rock bolts). In addition to costly breakdowns, transfer blockages can destroy conveyor belts or structures. The article presents research results on the possibility of monitoring the work state using the vibration diagnostics. The results prove that the recorded signal has characteristics that distinguish the signal recorded during regular operation from the signal from the moment of blocking the transfer point. The article proposes the possibility of using an automated monitoring work state based on a neural network detecting spectral entropy signal anomalies.
•Vibrodiagnostics monitoring of transfer point blockages is possible.•The characteristic features of the signal were detected and analyzed.•A method for detecting blockade states based on spectral entropy was developed.•Automated detection process using the RNN network.•The alarm starts before the transfer point is fully blocked.
The use of textiles produced from high tenacity(HT) polyester yarns as a reinforcement material in the mechanical rubber goods industries, mainly in the conveyor belt, is extensively increasing due ...to their high tensile strength, flexibility, thermal stability, modulus of elasticity, and light weightiness. To achieve the desired property of a conveyor belt, the reinforcement components undergo various processing stages; among those stages vulcanizing the reinforcement materials under high temperatures is the crucial process that determines the physical and mechanical properties of the conveyor belt. The main aim of this work was to analyze the effect of vulcanization parameters on the physio-mechanical properties of high tenacity polyester yarns and fabrics that are utilized to reinforce a conveyor belt. An extensive experimental study was conducted on a pre-activated HT polyester yarn of different linear densities and woven fabrics produced for the purpose of conveyor belt reinforcement by subjecting the yarns and fabrics to various aging temperatures for a certain period of aging time. Following the experiments, a comprehensive study and analysis were conducted on the tensile property of the yarns and fabrics. The finding revealed that thermal aging has an immense impact on determining the tensile strength and elongation of the yarn and woven fabric, which also has a direct influence on the properties of the conveyor belt. The analysis of experimental test results of polyester yarns and woven fabrics revealed that vulcanizing textile-reinforced conveyor belt at high temperatures (220 °C) could deteriorate the tensile strength and increase the elongation at break of the yarn, fabric, or belt.
Belt sag in belt conveyors, which is the deformation of the belt profile between two successive idlers, occurs during the transportation of the bulk material. In practice, bulk material is ...transferred upon a curved belt surface due to this sag. To apply this phenomenon to the numerical analysis, Discrete Element Method (DEM) and Finite Element Method (FEM) are coupled, where the data transfer between the methods repeated iteratively. It is aimed to investigate the effects of this process on the conveyor capacities and belt sags of different conveyor angles. Normal forces of bulk material, hence belt sags, increase as the data transfer is repeated. Capacities on the conveyor angles higher than 15° also increase, whereas the lower angles are not affected by this process. It is concluded that, in numerical applications aiming to acquire the belt sag and capacity of high conveyor angles, the repeated data transfer should be employed.
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•FEM DEM data transfer repeated iteratively to simulate the belt profile featuring the sag.•Effects of repeated data transfer on belt sags, conveyor capacities and inclination coefficient (k)•Normal forces, belt sags and conveyor capacities on conveyor belts increase iteratively as the data transfer is repeated.•Belt sags on each idler spacing can be acquired numerically for different conveyor angles.
As electricity prices continue to rise, the increasing need for energy management requires better understanding of models for energy-consuming applications, such as conveyor belts. Conveyor belts are ...used in a wide range of industries, including power generation, mining and mineral processing. Conveyor technological advances are leading to increasingly long conveyor belts being commissioned. Thus, the energy consumption of each individual belt conveyor unit is becoming increasingly significant. This paper proposes a generic energy model for belt conveyors with long troughed belts. The model has a two-parameter power equation, and it uses a partial differential equation to capture the variable amount of material mass per unit length throughout the belt length. Verification results show that the power consumption calculations of the newly proposed simpler model are consistent with those of a known non-linear model with an error of less than 4%. The online parameter identification set-up of the model is proposed. Simulations indicate that the parameters can be identified successfully from data with up to 15% measurement noise. Results show that the proposed model gives better predictions of the power consumed and material delivered by a long conveyor belt than the steady-state models in the current literature.
The purpose of this study is to investigate the effects of belt catalytic infrared drying (BCIRD), belt catalytic infrared blanching BCIRD (BCIRB-BCIRD), and hot water BCIRD (WB-BCIRD) on the ...structural and functional properties of sweet potato starch (SPS). The results revealed a decrease in the starch content of SPS by 5% after WB-BCIRD treatment. The starch granules subjected to BCIRD and BCIRB-BCIRD remained intact while the surface of WB-BCIRD treated granules cracked or even collapsed. In comparison with WB-BCIRD, the solubility of BCIRB-BCIRD SPS decreased by 2.725%, the water absorption decreased by 3.4024%, and the oil absorption decreased by 3.7904%. While the degradation temperature increased by 20 °C and the transparency increased by 0.9745%, and. The heat treatment breaks the starch chain and destroys the arrangement of the crystal zone, which affects its functional properties. BCIRB-BCIRD is better at retaining the structural and functional properties of SPS.
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•The integration of blanching and drying of sweet potato chips was realized.•After integrated processing, starch granules maintained their complete shape.•The starch obtained by integrated processing had higher thermal stability.
This article performs a comparative analysis of noise generated by conveyor belts with different design parameters. The study was conducted for belts with the same tensile strength, differing in the ...physical parameters of the cover rubber. Noise emission measurements were performed on a laboratory belt conveyor. The test on the stand allowed for the determination of the noise emission as a function of variable operating parameters: the tensioning force and linear speed of the belt. Research results indicated a significant impact of speed on the emitted noise. The effect of belt tension on noise emission is small, and it is definitely less significant than the effect of linear speed. The results also show that it is possible to select a conveyor belt that emits less noise under the same operating conditions. The analysis of the results allowed us to determine the impact of the physical parameters of the belt covers on the emitted noise.
In this paper are presented the operating parameters for a conveyor belt in a stone processing plant. The stone processed in this kind of installation could be ballast or granite. Because of this in ...the installation can be done a different arrangement for stone processing. The conveyor belts from the installation are the mainly way of transport the materials and for this it has to be done calculation for the optimal parameters of functioning.
Despite huge progress made, state‐of‐the‐art numerical weather prediction systems occasionally experience severe forecast busts for the large‐scale extratropical circulation. This study investigates ...one of the most severe forecast busts for Europe in the European Centre for Medium‐Range Weather Forecasts integrated forecasting system (IFS) in recent years. The forecast bust occurred in March 2016 and was associated with a misforecast of the onset of a blocking regime. We investigate the evolution of the forecast error in the IFS ensemble by employing a potential vorticity perspective combined with Lagrangian diagnostics. We show that the error grows rapidly from an initially small perturbation in the detailed structure of an upper‐level trough near Newfoundland. This trough triggers strong diabatic warm conveyor belt activity in the North Atlantic region. The misrepresentation of this warm conveyor belt activity in the ensemble forecast amplifies the initial condition error and communicates it downstream into Europe. Specifically, the ensemble underestimates poleward warm conveyor belt ascent and associated warm conveyor belt outflow into high latitudes. Instead, all ensemble members forecast too strong warm conveyor belt outflow further to the south, which ultimately results in a wrong forecast of the upper‐level Rossby wave pattern over Europe. This case study shows that warm conveyor belts and the associated latent heat release in slantwise ascending air can trigger a nonlinear feedback mechanism that amplifies forecast error strongly and communicates it into regions far downstream. It corroborates the fact that multiscale interactions and moist‐and dry‐dynamical processes ranging from microphysical to synoptic scales need to be represented accurately in numerical weather prediction, in order to predict the extratropical large‐scale circulation correctly.
The onset, decay, and transition of large‐scale flow regimes constitute a key challenge in subseasonal numerical weather prediction and are prone to forecast error. In this study, we document one of the severest forecast busts in the ECMWF IFS ensemble in recent years. We show that, during the onset of European blocking, a poorly forecast warm conveyor belt amplified and propagated downstream an initial condition error, corroborating the need to represent cloud diabatic processes correctly in order to improve extended‐range forecasts.
•Many simultaneous inelastic contacts with friction between bodies is considered.•Positioned object is a rigid body with a soft base, corners and edges.•In positioning process model the frictional ...Stribeck's effect can be ignored.•Free motion with friction on oblique plane does not rotate 3D object spontaneously.
The paper presents a model of the positioning process of cuboidal objects on an oblique plane with barriers, caused by the interaction of inertia, gravity and contact forces. In this model, the contact area of the object base with the bearing planes is represented by evenly spaced discrete elements and the corners and edges of the object identify the contact with the positioning barriers. The object performs free spatial movement and may be in simultaneous contact with many bearing surfaces with different frictional properties. The static Bengisu-Akay friction model represents tangent contact forces, and the nonlinear Kelvin collision model describes normal forces. Due to high sliding velocities, the Stribeck's effect in the friction model does not have a significant impact on the course of the positioning process, hence it was assumed that the static and kinetic friction coefficients are equal to each other. Moreover, on the basis of the conducted analyses of the results of numerical and experimental tests, a geometrical configuration of the positioning barriers was proposed, allowing the object to be intercepted on an oblique plane and placed on the outfeed conveyor.
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