Bearings and other revolute pairs in gear drives will form clearances due to wear after working for a long time, which will aggravate the vibration and noise of the gear. Therefore, taking the gear drives with revolute pair clearance as the research object, the calculation formulas of the backlash and contact ratio is derived, and the time-varying mesh stiffness model considering the clearance is presented in this work. Then, a nonlinear dynamic model for the gear drives with revolute pair clearance is proposed by combining the backlash, contact ratio and the time-varying mesh stiffness. The effects of the clearance on the meshing stiffness, load sharing factor and nonlinear behavior are investigated. Results indicate that the revolute pair clearance weakens the meshing stiffness and increases working hours in single teeth contact area, thereby increasing the risk of premature failure of the gear drive. In addition, the revolute pair clearance has negligible effect on the nonlinear beh... [more]

This paper presents the modeling and simulation of an industrial-scale chemical looping combustion (CLC) power plant, including all process units (reactors, flue gas treatment units, heat integration, steam cycle, and CO2 compression train). A model of a 525 MWth CLC power plant was built using a rigorous representation of the solid fuel and oxygen carrier. Petcoke was considered the main fuel of interest in this study, and it is compared with other solid fuels. The flue gas compositions obtained with the model show that cleanup units are mandatory to comply with CO2 quality requirements. High levels of flue gas treatment, including 97.1% deNOx and 99.4% deSOx, are needed to achieve typical specifications for captured CO2. This is mainly due to the high level of contaminants in the fuel, but also to the absence of nitrogen in the CLC flue gas, thus resulting in higher concentrations for all substances. The high level of flue gas treatment is thus one of the important challenges for sol... [more]

Industrial automation systems, such as chemical processes, manufacturing processes, power networks, transportation systems, sustainable energy systems, wireless sensor networks, robotic systems, and biomedical systems, are becoming more complex [...]

Methanol is considered a sustainable alternative energy source due to its ease of storage and high-octane rating. However, the conventional methanol production process is accompanied by resource consumption and significant greenhouse gas emissions. The electrochemical reaction of electrochemically reacted hydrogen (H2) with captured carbon dioxide (CO2) offers an alternative route to methanol production. This paper presents a new green poly-generation system consisting of a parabolic trough solar collector (PTC) unit, an organic Rankine cycle (ORC) unit, a CO2 capture unit, an alkaline electrolysis unit, a green methanol synthesis and distillation unit, and a double-effect lithium bromide absorption refrigeration (ARC) unit. The system mainly produced 147.4 kmol/h of methanol at 99.9% purity, 283,500 kmol/h of domestic hot water, and a cooling load of 1341 kW. A total 361.34 MW of thermal energy was supplied to the ORC by the PTC. The alkaline electrolysis unit generated 464.2 kmol/h o... [more]

A compact static mixer for gas−liquid dispersion in pipelines is studied in this paper with a Reynolds averaged two fluid model approach. A procedure based on the lumped parameter solution of a population balance model is applied to obtain the bubble Sauter mean diameter needed to model the interphase forces. The gas distribution in the pipe is analyzed in two different operative conditions and the efficiency of the static mixer is assessed in terms of the gas homogeneity in the pipe section, with low coefficients of variations being obtained. A computational model to obtain the volumetric mass transfer coefficient, kLa, developed for partially segregated systems is applied finding kLa values comparable to those typically obtained with other static mixers. The proposed computational model allows us to locally analyze the oxygen transfer rate by observing the limitations due to gas accumulation behind the body of the static mixer, which leads to the local depletion of the driving force.... [more]

This article describes the performance of hemp shives, a co-product of the hemp industry, when used as an adsorbent to recover copper present in aqueous solutions by a batch method. Two materials provided by an industrial partner, namely water-washed hemp shives (SHI-W) and Na2CO3-activated shives (SHI-C), were studied. Two important variables in the water treatment industry, i.e., pH and ionic strength of the solution, were studied to evaluate their impact on the purification performance of the materials. The results obtained clearly indicated that the performance in terms of Cu removal obtained from the SHI-C material was significantly higher than that obtained with SHI-W, mainly due to the structural and chemical modifications after carbonate treatment. For each dose of this adsorbent, a percentage of recovery between 90 and 100% was achieved, independently of the pH value in the range 3−5. In the case of SHI-W, the highest values were between 60 and 75% and were both dependent on t... [more]

Long-term development of fluvial reservoirs causes regular changes in the microscopic pore-throat structure, physical properties and phase permeability curves of the reservoirs, and the evolution history of different oil layer varies. These effects can be explored using a four-dimensional (4D) model of the maturing field. The logging curves of 89 sand bodies of the Nanpu No. 2 structure in the Bohai Bay Basin were restored to the non-water flooded state based on the changing status of water flooding layers at different stages and levels, and an original geological model was established by combining data for the old wells. The time-varying relationship was incorporated in the dynamic model with surface flux as the variable, and the numerical simulation analysis was conducted based on the reservoir time-varying characteristics. The results showed that ① the logging data of the water-flooded layer significantly affected the simulation results of the geological model and can only be used f... [more]

To explore the stability analyses and control methods for surrounding rocks in deep hard rock shafts, this paper is based on field engineering geological surveys and laboratory rock mechanics tests and relies on the main shaft being constructed in the Shaling Gold Mine of China as the engineering background. The quality of the rock mass is evaluated by the Q system, rock mass rating (RMR) and geological strength index (GSI). The mechanical parameters of the surrounding rock mass of the shaft are calculated by using the generalized Hoek−Brown failure criterion, and the main support system is determined based on the rock mass classification system. Based on the finite element method, a two-dimensional plane strain model is constructed to analyze and evaluate the deformation and plastic region range of surrounding rocks for different support systems. On this basis, considering the dilatancy and plastic softening characteristics of hard rock masses, an analytical solution of the stress, st... [more]

Gas−liquid flow is a significant phenomenon in various engineering applications, such as in nuclear reactors, power plants, chemical industries, and petroleum industries. The prediction of the flow patterns is of great importance for designing and analyzing the operations of two-phase pipeline systems. The traditional numerical and empirical methods that have been used for the prediction are known to result in a high inaccuracy for scale-up processes. That is why various artificial intelligence-based (AI-based) methodologies are being applied, at present, to predict the gas−liquid flow regimes. We focused in the current study on a thorough comparative analysis of machine learning (ML) and deep learning (DL) in predicting the flow regimes with the application of a diverse set of ML and DL frameworks to a database comprising 11,837 data points, which were collected from thirteen independent experiments. During the pre-processing, the big data analysis was performed to analyze the correla... [more]

The power sector in Uganda has increased steadily, focusing majorly on rural electrification to increase the proportion of the rural population accessing electricity using grid extension and isolated mini-grid approaches. Hydropower mini-grids implemented in rural communities have issues regarding system failures leading to shutdowns and load shedding. A study on an existing isolated hydropower mini-grid was made to find the possible causes. A review of published articles and reports, and an analysis of enrollment patterns, energy sales, and load demand was carried out. A field survey with a guided questionnaire to collect information about real energy demand data was carried out. The performance of the system was accomplished through simulation using HOMER pro × 64 software. The findings from the study show a reduction in customer enrollment, a reduction in energy sales, and a reasonable number of system shutdowns. Hybridization of the existing hydropower was modeled with different op... [more]

Demand trends towards mass customization drive the need for increasingly productive and flexible assembly operations. Walking-worker assembly lines can present advantages over fixed-worker systems. This article presents a multiproduct parallel walking-worker assembly line with shared automated stations, and evaluates its operational performance compared to semiautomated and manual fixed-worker lines. Simulation models were used to set up increasingly challenging scenarios based on an industrial case study. The results revealed that semiautomated parallel walking-worker lines could achieve greater productivity (+30%) than fixed-worker lines under high-mix low-volume demand conditions.

The heat and mass transfer to solid particles in one-dimensional oscillating flows are investigated in this work. A meta-correlation for the calculation of the Nusselt number (Sherwood number) is derived by comparing 33 correlations and data point sets from experiments and simulations. These models are all unified by their dependencies on the amplitude parameter 10−3≤ϵ≤103 and the Reynolds number 10−1≤Re≤106, while the ϵ-Re plane is applied as a framework in order to graphically display the various models. This is the first study to consider this problem in the entire ϵ-Re plane quantitatively while taking preexisting asymptotic models for various areas of the ϵ-Re plane into account.

In this paper, a double locally weighted extreme learning machine model based on a moving window is developed to realize process modeling. To improve model performances, an improved sparrow-searching algorithm is proposed to optimize the parameters of the proposed model. The effectiveness of the proposed model and algorithm are verified by data from a hematite grinding process. The experimental results show that the proposed algorithm can significantly improve the global search ability and convergence speed in the parameter optimization of the proposed model. The proposed model can correctly estimate the grinding particle size which is expected to be applied to other complex industries.

In a satellite network, the inter-satellite link can facilitate the information transmission and exchange between satellites, and the packet routing of the inter-satellite link is the key development direction of satellite communication systems. Aiming at the complex topology and dynamic change in LEO satellite networks, the traditional single shortest path algorithm can no longer meet the optimal path requirement. Therefore, this paper proposes a multi-path routing algorithm based on an improved breadth-first search. First, according to the inter-satellite network topology information, the improved breadth-first search algorithm is used to obtain all the front hop node information of the destination node. Second, all the shortest paths are obtained by backtracking the path through the front hop node. Finally, according to the inter-satellite network, the bandwidth capacity of the traffic and nodes determines the optimal path from multiple shortest paths. However, due to the high dynam... [more]

In this study, an aerosol fluidized bed is used to coat particles. A new aerosol generator is used to obtain coating solution droplets with a diameter of around 1 μm or smaller. Glass particles, which have a mean diameter of 653 μm, were the non-porous core material and the coating solution was sodium benzoate. Scanning electron microscope pictures were analyzed by MATLAB image processing for evaluating the coverage with the curvature effect. Monte Carlo simulation was used to describe the coating of fluidized particles by aerosol droplets. The purpose of this work was the determination of possible island growth on particles, and investigation of the reasons of it by comparing the experimental and simulation results. The preferential deposition of droplets on already occupied positions is seen as the main possible reason for island growth.

Modeling of the separation of catalyst particles from gas using two devices, a cyclone and a novel separator with arc-shaped elements, was performed for fluidized-bed dehydrogenation of C4−C5 paraffins to isoolefins as an example. The proposed dust collector allows one to reduce erosive wear by several times (~6.5-fold) in identical regimes and at identical parameters of the process. The effect of particle size on erosive wear was analyzed under near-industrial conditions; the regions most susceptible to wear in the analyzed devices were identified, as well as the functions describing the dependence between the erosive wear rate and particle diameter for the cyclone and separator with arc-shaped elements, making it possible to predict wear in the devices were obtained.

For countries where catalytic cracking gasoline is the primary source, the proposed technology consists in separating a benzene-rich fraction from catalytic cracking gasoline in order to be processed further together with reforming gasoline in a unit dedicated to aromatics extraction. In this way, two benefits are obtained: a benzene-rich fraction as raw material for extraction and the leftover fraction that satisfies the benzene content standards as a qualified product. It is established to use the divided wall distillation model, single-column distillation model, and double-column distillation model. Sensitivity analysis and SQP optimization are used to identify the ideal operating conditions and gasoline yield. Economic research shows that the divided wall and single-column distillation models have more potential for growth. It offers theoretical direction for businesses to design and optimize the pertinent process.

Microwave heating has a wide range of applications in the fields of industrial heating and drying. However, when microwave heating is applied to the thin film, it will be challenging due to its low loss and large heat dissipation area. In this paper, a double-ridged waveguide for thin-film heating is proposed. The double ridge structure is employed to enhance the electric field, thereby increasing the power-loss density in the thin film. Firstly, a double-ridged waveguide, in which the electric field strength can be about 2.5 times that of the conventional waveguide, was designed based on the transverse resonance method and the electromagnetic field simulation. Then, a multiphysics model was built to analyze the heating performance of the ridged waveguide, in which the electromagnetic field and heat transfer are coupled. The simulation results show that the heating performance of the proposed waveguide will be 35.0 times that of the conventional waveguide. An experiment was carried out... [more]

In the pharmaceutical industry, tablets are a common dosage form. As part of the manufacturing process, powder in a tablet press passes through a feeding system called the feed-frame before reaching the die cavity. Under different manufacturing conditions (e.g., paddle speed, turret speed), issues such as segregation of powder blend components, over lubrication, and drug particle attrition often occur in the tablet press feed-frame, which affect the final drug product quality. Therefore, developing a particle-scale understanding of powder behavior in a feed-frame is essential. This paper used the discrete element method (DEM) to study powder flow in the feed-frame of a kg-pharma RoTab tablet press. Simulation results show that an increase in paddle speed has less effect on tablet mass than turret speed and that an increase in turret speed reduces tablet mass and increases variability in the tablet mass. The effect of paddle speed and turret speed on the API content in the tablet is sma... [more]

Investigations were undertaken to study the drying kinetics of pretreated and unblanched leaves of Moringa oleifera dried in a fluidized bed dryer (FBD) using nine established thin layer drying mathematical models. The statistical software tool Statistica was utilized to carry out regression analysis, and the model constants were evaluated using nonlinear regression. In nonlinear regression, the R2 and reduced χ2 were employed to evaluate the goodness of fit of several mathematical models to the data generated experimentally. The model with the highest R2 and the lowest reduced χ2 and root mean square error (RMSE) values was adjudged as best fit to the drying curves. The drying kinetics of drumstick leaves was best explained by the Midilli−Kucuk model, followed by the Logarithmic model. The R2, reduced χ2, and RMSE values of the Midilli−Kucuk model under fluidized bed drying varied from 0.9982−0.9997, 0.00003−0.00029, and 0.0059−0.0166 in pretreated and 0.9945−0.9961, 0.00019−0.00054 a... [more]

Improving surface quality attributes is a critical task in the production of micro-sized near-net-shaped components for end-use applications using additive manufacturing techniques. In the present study, we investigated the effect of fused deposition modeling (FDM) process parameters such as layer thickness, part orientation, raster width and raster angle on the surface quality characteristics of as-fabricated test specimens in order to develop the assembly of a flapping wing micro mechanism. Through a Box−Behnken design, a suitable experimental strategy was developed, and test specimens were manufactured. The performance of the experiments was statistically assessed using multi-response analysis of variance (ANOVA). The microstructures of the test specimens produced with various processing parameters were examined using a scanning electron microscope to identify micro surface flaws under various processing conditions. Furthermore, the optimal FDM parameters for improved surface qualit... [more]

Developing a model that can accurately predict internal fractured reservoirs in the context of the ultra-low physical properties of carbonate rocks by only employing conventional mathematical methods can be very challenging. This process is challenging because the relationship between basic fracture parameters and the logging response in carbonate reservoirs has not been studied, and the traditional method lacks adaptability due to the complex relationship between basic fracture parameters and the logging response. However, data-driven approaches supplemented by machine learning algorithms based on multi-layer perceptrons (MLP) provide a more reliable solution to this challenge. In this paper, a classical fracture parameter evaluation data set is established using fracture porosity, fracture density, fracture length, and fracture width data that can be identified by resistivity and acoustic imaging logging. Another data set can be composed of different types of logs, and it can be used... [more]

A model that captures realistic viral growth dynamics has been developed based on a continuous and semi-continuous production model of an influenza A virus. This model considers viral growth parameters such as viral latency. It also captures the lag observed during the early production of viruses in a culture and explains later-phase growth dynamics. Furthermore, a sensitivity analysis was performed to investigate the effects of each input on each output. This revealed that production of defective interfering particles (DIPs) highly depends on the number of cells introduced to the viral reactor. The rationale for this is, as per the model, that a reduction in number of cells to be infected causes a reduction in DIPs formed as rate of viral infection decreases. Finally, a flowsheet model was created to optimize the continuous platform, including number of cells supplied to the viral reactor. From this, it was observed that the peak number of DIPs formed could be reduced by one-third. Fi... [more]

The combustion and explosion characteristics of cassava starch and the dispersive physical motion law of dust were systematically studied using a 20 L (=0.02 m3) spherical explosive test device and the numerical simulation method. The experimental results show that the explosion pressure first increases and then decreases with increasing ignition delay time, dust concentration, and spray pressure in the dust storage tank. The maximum explosion pressure was obtained with a dust concentration of 750 g/m3, while the maximum rate of pressure increase was obtained when the concentration was 250 g/m3. The calculated maximum explosion index was 22.3 MPa∙m∙s−1. The simulation results show that the physical movement law of the dust was as follows: high initial velocity → gradual decrease in diffusion velocity → upward linear movement of dust → outward diffusion motion → continuous disorder motion → free settlement → gradual reduction and disorder state → finally, complete settlement. With a pow... [more]

Digital technologies for cyber-physical systems are rapidly advancing, and the ubiquity of the Internet of Things (IoT) has created significant challenges for academic, industrial, and service applications due to high dimensionality, noise contamination, incompleteness, inconsistency, and massive amounts of data [...]