This study proposes a novel maximum power point tracking (MPPT) control strategy for the solar photovoltaic power system (SPPS). The proposed system adopts two solar photovoltaic modules of 430 W, which are connected to a boost converter and an MPPT controller, since the traditional MPPT algorithm (such as perturbation and observation [P&O] algorithm) can hardly reach maximum power point (MPP) under low irradiance level and partial shading conditions (PSC), which leads to the low efficiency of the SPPS. The speed of light optical path difference measurement (SLOPDM) MPPT control strategy has been developed in this study to overcome this problem. The estimation of the optical path angle difference is used as the basis for the proposed control strategy. This is done by determining the relationship between the optical path angle difference, solar photovoltaic power impedance Rspv and load Ro, and then calculating the duty cycle corresponding to the MPP, which then drives the boost convert... [more]

With the development of coal mining, the use of elbows has diversified the forms of underground backfill pipelines, which has inevitably complicated the transportation characteristics of filling slurry in the pipeline, thus affecting the entire backfilling system. The objective of this study is to numerically investigate the running state of cemented paste backfilling (CPB) slurry and coarse particles at different velocities by transporting in bend pipes. To better understand the transportation state of CPB slurry in pipeline, a computational fluid dynamics (CFD) model—mixture model was developed to study the transportation of CPB slurry. The volume distribution of coarse particles in slurry under different pipe types and different flow rates, as well as the velocity profiles of slurry at different positions, were simulated and analyzed, and the pressure losses under different pipe types were compared. The results show that the distribution of coarse particles varies with the tube type... [more]

Modal analysis on micro-vortex generator (MVG)-controlled supersonic flow at different Mach numbers is performed in this paper. The purpose of this investigation is to clarify the different properties of streamwise and ring-like vortical modes, and the effects of different Mach numbers on these modes, to further understand the vortical structures as they travel from MVG down to the shock wave/boundary-layer interaction (SWBLI) region. To this end, a high order and high resolution large eddy simulation (LES) was carried out, which identified the vortical structures behind the MVG and in the shock wave/boundary-layer interaction (SWBLI) region in the supersonic ramp flow with flow speeds of three different Mach numbers 1.5, 2.0, and 2.5. The proper orthogonal decomposition (POD) then was adopted to investigate the modes of the fluctuation flow field. It emerged that the streamwise and ring-like vortical modes were disparate in energy distribution, structural order, frequency and amplitud... [more]

is a traditional medicinal plant renowned as a cure for many diseases due to the presence of bioactive compounds. The Solanum nigrum complex refers to a group of more than 30 closely related but morphologically distinct taxa. Five indigenous taxa of this complex were investigated for their medicinal potential by using methanolic extracts. The efficacy of each plant was different for each of the seven bacteria studied. On comparing the MIC values, S. americanum was found to be most potent against Bacillus licheniformis (34 µg/mL), S. chenopodioides against Escherichia coli (78 µg/mL), S. nigrum against Bacillus licheniformis (49 µg/mL) and Escherichia coli (49 µg/mL), S. retroflexum against Escherichia coli (30 µg/mL), and S. villosum against Proteus mirabilis (45 µg/mL). The extracts were also subjected to six antioxidant assays. Moderate scavenging activity was observed by all plants in the DPPH free radical assay, but S. chenopodioides was the most effective. The total phenolic conte... [more]

The Aquila Optimizer (AO) algorithm is a meta-heuristic algorithm with excellent performance, although it may be insufficient or tend to fall into local optima as as the complexity of real-world optimization problems increases. To overcome the shortcomings of AO, we propose an improved Aquila Optimizer algorithm (IAO) which improves the original AO algorithm via three strategies. First, in order to improve the optimization process, we introduce a search control factor (SCF) in which the absolute value decreasing as the iteration progresses, improving the hunting strategies of AO. Second, the random opposition-based learning (ROBL) strategy is added to enhance the algorithm’s exploitation ability. Finally, the Gaussian mutation (GM) strategy is applied to improve the exploration phase. To evaluate the optimization performance, the IAO was estimated on 23 benchmark and CEC2019 test functions. Finally, four real-world engineering problems were used. From the experimental results in compar... [more]

Shale oil reservoirs are characterized by having various types of vertical sublayers, a large contrast in rock mechanical properties, well-developed bedding, and high clay content, which are likely to cause rock elastic−plastic deformation. In numerical simulations of hydraulic fracture (HF) propagation in the shale oil reservoirs, the effects of rock elastic−plastic deformation and complex bedding structure on the layer-crossing behavior of HF are not considered. To understand the mechanism of HF height growth in shale oil reservoirs, we used the cohesive zone method to establish an elastic−plastic finite element model of HF propagation by considering the effects of shell limestone interlayers, the Mohr−Coulomb yield criterion for shear−plastic failure, the cross-mechanical interaction between bedding and shale oil reservoir, and the complex situations such as the HF height across high-electrical resistivity bedding and high-conductivity fractures. The effects of internal friction ang... [more]

It is important to monitor and evaluate the growth of microorganisms in order to accurately judge the situation of blood microbial infection. In this paper, diode laser wavelength modulation spectroscopy (DLWMS) technology is used to design a set of low-cost, high sensitivity, fast dynamic responses and a non-invasive trace gas measurement system, which can quickly and accurately assess the concentration of carbon dioxide (CO2) produced by blood microbial reproduction. The measurement principle and spectral processing algorithm of DLWMS are introduced first. The automatic and rapid detection of CO2 is realized through a self-designed optical system. By using the system to detect blood infection, the accuracy of the technology was verified. Therefore, it also indicates that DLWMS CO2 monitoring is a highly sensitive, fast-response and non-invasive technology, which can accurately and quickly determine blood infection and meet the clinical application requirements of human septicemia, ba... [more]

Aiming at NO (NO 90%, NO2 10%) and SO2 in simulated vessel emissions, denitration and desulfurization were studied through ozone oxidation combined with seawater as absorbent. Specifically, the different influencing factors of denitration and desulfurization were analyzed. The results indicated that the oxidation efficiency of NO can reach over 90% when the molar ratio of O3/NO is 1.2. Ozone oxidation and seawater washing in the same unit can decrease the temperature of ozone oxidation of NO, avoid high temperature ozone decomposition, and enhance the oxidation efficiency of NO. When NO inlet initial concentration is lower than 800 ppm, the NO removal efficiency can be improved by increasing NO inlet concentration, and when NO inlet initial concentration is greater than 800 ppm, increasing the concentration of NO would decrease the NO removal efficiency. Increasing the inlet concentration of SO2 has minor effect on desulfurization, but slightly reduces the absorption efficiency of NO d... [more]

The ability to take non-invasive Raman measurements presents a unique opportunity to use one Raman probe across multiple vessels in parallel, reducing costs but making measurements infrequent. Under these conditions, infrequent and irregular feedback signals can result in poor closed-loop control performance. This study addressed the issue of infrequent and irregular Raman measurements using a linear dynamic model developed from interpolated data to predict more frequent measurements of the controlled variable. The simulated monoclonal antibody production was sampled hourly with white noise added to the simulated glucose concentration to replicate real Raman measurements. The hourly samples were interpolated into 15 min intervals and a linear dynamic model was developed to predict the glucose concentration at 15 min intervals. These predicted values were then used in a feedback control loop by using model predictive control or a conventional proportional and integral controller to cont... [more]

During the construction of tunnels in saturated water-bearing sand stratum, water and mud inrush disasters often occur. Grouting is the most convenient and effective method to improve the mechanical properties of the soil and prevent groundwater seepage. The reasonableness of the Discrete Element Method (DEM) contact parameters is verified by comparing the repose angle test with that obtained by simulations. The grouting model of saturated water-bearing sand stratum was established based on the Volume of Fluid-Discrete Element Method (VOF-DEM). Then, the effects of sand stratum porosity and grouting pressure on grouting were discussed. The results show that (1) in dense sands, the permeation diffusion of the slurry dominates, whereas in loose sands, the compaction zone is well developed. (2) Loose sand has a wider propagation of stress and dense sand has a larger increase in the stress state. (3) In loose sand the slurry diffusion is significantly affected by gravity, whereas in dense... [more]

Actual diffusion activity function is an important metric utilized to describe the diffusion activities of a vacancy defect substance. In this paper, we propose a deep learning three-dimensional convolutional CNN model (D3-CNN). A 3D convolution has its kernel slides in three dimensions as opposed to two dimensions with 2D convolutions. 3D convolution is more suitable for three-dimensional data. We also propose an amplification learning technique to predict the actual diffusion activity of a vacancy defect substance, which is impacted by the geometrical parameters of the defect substance and the vacancy distribution function. In this model, the geometric parameters of a three-dimensional constructed vacancy defect substance are generated. The 3D dataset is obtained by the atoms diffusion defect (ADD) simulation model. The geometric parameters of the 3D vacancy defect substance are computed by the proposed amplification technique. The 3D geometric parameters and the diffusion activity v... [more]

The incursion of disruptive technologies, such as the Internet of Things, information technologies, cloud computing, digitalization and artificial intelligence, into current production processes has led to a new global industrial revolution called Industry 4.0 or Manufacturing 4.0. This new revolution proposes digitization from one end of the value chain to the other by integrating physical assets into systems and networks linked to a series of technologies to create value. Industry 4.0 has far-reaching implications for production systems and engineering education, especially in the training of mechatronic engineers. In order to face the new challenges of the transition from manufacturing 3.0 to Industry 4.0 and 5.0, it is necessary to implement innovative educational models that allow the systematic training of engineers. The competency-based education model has ideal characteristics to help mechatronic engineers, especially in the development of specific competencies. This article pr... [more]

The conformal loading effects of P3CT-Na polymers on ITO/glass samples were investigated using different concentrations of P3TC-Na/water solution, which significantly influenced the device efficiency of the resultant inverted perovskite solar cells. The obtained water-droplet contact angle images, surface morphological images, photoluminescence spectra and X-ray diffraction patterns show that the hydrophilic moiety of the P3CT-Na polymers plays an important role in the conformal loading effects, thereby resulting in a smoother perovskite crystalline film due to the formation of merged grains. It is noted that the average power conversion efficiency increases from 14.83% to 17.27% with a decrease in the concentration of the P3CT-Na/water solution from 60 wt% to 48 wt%.

The diagnosis of rolling bearing faults has become an increasingly popular research topic in recent years. However, many studies have been conducted based on sufficient training data. In the real industrial scene, there are some problems in bearing fault diagnosis, including the imbalanced ratio of normal and failure data and the amount of unlabeled data being far more than the amount of marked data. This paper presents a rolling bearing fault diagnosis method suitable for different working conditions based on simulating the real industrial scene. Firstly, the dataset is divided into the source and target domains, and the signals are transformed into pictures by continuous wavelet transform. Secondly, Wasserstein Generative Adversarial Nets-Gradient Penalty (WGAN-GP) is used to generate false sample images; then, the source domain and target domain data are input into the migration learning network with Resnet50 as the backbone for processing to extract similar features. Multi-Kernel M... [more]

Fast computation of the elastic deformation integrals of dry contact is accomplished using multigrid techniques. The method is called multi-level multi-integration, which enables the efficient numerical solution of contact pressure for large dry-contact problems. The computing effort can be reduced to O (NlogN) operations, compared to that of classical solution methods, O (N2). The fast integration technique can be straightforwardly applied to computing sub-surface stresses. As an example, the pressure and stress distribution of the contact of wire rope and friction lining, a large calculation due to the wire rope’s complicated construction, were fast solved. Subsequently, the friction lining’s transient temperature, when the wire rope was sliding, was solved using multigrid techniques.

The use of multiphase electric drives in industrial applications has increased in the last few years. These machines’ advantages over the three-phase system make them appropriate for harsh working situations. To increase their inherent reliability, some authors have been working in sensorless control schemes, where the absence of an encoder ensures proper system performance. Nevertheless, these sensorless control systems present some problems due to the uncertainties of the parameters. In this regard, using extended Kalman filters overcomes this situation, since Kalman filters consider the system error and measurement error in the estimation process. However, when the three-phase Kalman filters are extended to the five-phase case of study, the complexity of the problem increases substantially. In this work, the authors propose an extended Kalman filter, which discomposes the original state equation, reducing the complexity of the estimation stage. In addition, the system suppresses the... [more]

Species of the genus Artemisia mainly biosynthesize sesquiterpene lactones. Achillin is a guaianolide-type sesquiterpene lactone isolated from Artemisia ludoviciana; it has shown antibacterial and anti-inflammatory activities. In addition, achillin exhibits a significant chemosensitizing effect on hepatocellular carcinoma cells resistant to paclitaxel (PTX). The objective of this study was to establish a callus culture from different explants under conditions of light and total darkness to produce achillin. To obtain in vitro cultures, explants of leaves, nodes, internodes, and roots were used, and they were cultured in MS medium with 0.1 mg/L of kinetin (KIN) or benzyl amino purine (BAP) and/or naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), indole-3-acetic acid (IAA) and 4-amino-3,5,6-trichloro-2-pyridine carboxylic acid (PIC) at 0.1 and 1.0 mg/L. Of all treatments, internodes with BAP (0.1 mg/L) and PIC (1.0 mg/L) grown under photoperiod showed the best friable... [more]

This paper presents the multi-objective optimization of a crude oil hydrotreating (HDT) process with a crude atmospheric distillation unit using data-driven models based on bootstrap aggregated neural networks. Hydrotreating of the whole crude oil has economic benefit compared to the conventional hydrotreating of individual oil products. In order to overcome the difficulty in developing accurate mechanistic models and the computational burden of utilizing such models in optimization, bootstrap aggregated neural networks are utilized to develop reliable data-driven models for this process. Reliable optimal process operating conditions are derived by solving a multi-objective optimization problem incorporating minimization of the widths of model prediction confidence bounds as additional objectives. The multi-objective optimization problem is solved using the goal-attainment method. The proposed method is demonstrated on the HDT of crude oil with crude distillation unit simulated using A... [more]

In the present study, we investigated and compared the effect of microwaves and freeze-drying methods on the dehydration and rehydration kinetics in the phenolic, anthocyanin, aroma profiles, and antioxidant properties of tree tomato fruit (Solanum betaceum). The tree tomatoes were dried using microwaves at 350 W, 500 W, and 650 W, and then freeze-dried. The obtained drying curves were processed to find the most suitable mathematical modeling among the different moisture ratio expressions. Total phenolics, total anthocyanins, total flavonoids total carotenoids, vitamin C, Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were tested. Using High performance Liquid Chromatography (HPLC), phenolic and anthocyanin compound profiles were identified. The aroma profile was analyzed using gas chromatography-MS. The Midilli model, among others, precisely describes the dehydration methodology of all used drying methods with the coefficient of determination R2 = 0... [more]

This work provides a case study on the indoor environment and ventilation rate of naturally ventilated research student rooms in Chinese universities. In the measured room, air temperature, relative humidity and carbon dioxide (CO2) concentration were monitored during the heating period for 4 weeks. The number of indoor occupants, occupied time of the room and window/door-opening cases were simultaneously recorded. Results showed the research student room was occupied for an average of 12.0 h each day. Due to a large indoor and outdoor temperature difference during the heating season, and occupants’ adaption to indoor environment, indoor occupants seldom open windows/doors for ventilation. Air exchange of the room only by air infiltration cannot meet the ventilation requirement. As a result, an average of 77.6% of measured CO2 data each day exceeded 1000 ppm during occupied time. In fact, according to CO2 data, it was observed that window/door opening could effectively decrease indoor... [more]

Steam is commonly used for heating in industrial production and transmitted through the steam network. Along with the decarbonization of energy generation and utilization, electric boiler and combined heat and power (CHP) became the alternatives for steam generation. Thus, the steam network is becoming tightly coupled with the power system, which brings new challenges in the simulation and operation of the combined electric and steam system (CESS). A novel simulation approach for CESS that can balance both the simulation accuracy and speed is proposed. Piecewise linearization of the saturated steam property is used for model simplification, which accelerates the simulation speed while ensuring the accuracy. Meanwhile, the heat loss of the steam network takes both condensate loss and heat dissipation into account, which further improves the accuracy of heat loss calculation. In view of model solving, two computation frameworks are provided for back-pressure and extraction condensing the... [more]

The presented article deals with the design of equipment for measuring and testing hydrostatic transducers. The presented design of the device is used for measuring and testing hydrostatic transducers in laboratory conditions, especially hydraulic pumps. This shortens the testing time, with a reduction in economic costs for testing the elements of the hydraulic circuit or testing the properties of pumps and hydraulic fluids. By simulating the operating conditions occurring in practice, it is possible to verify and evaluate the parameters of mobile energy means used in hydraulic mechanisms. The designed laboratory equipment is used for measuring and testing hydrostatic transducers and properties of hydraulic fluids. A verification measurement of the flow of the hydrostatic transducer was performed on the proposed laboratory equipment. The output of the measurements is a confirmation of the functionality of the designed equipment. The results of the verification measurement were compared... [more]

The online measurement of coal ash has overcome the shortcomings of chemical tests. However, there could be large fluctuations and errors in the results of online ash monitors because of the transient change in coal quality resulting from different geological conditions in the mining process. In this study, to resolve the problems of the dual-energy γ-ray online ash monitor in the Linhuan Coal Preparation Plant, we investigated the internal factors, such as the composition of multimineral and multicoal, and external factors, such as the moisture and impurities, which affect the measurement results of the coal ash monitor. Furthermore, we developed a mathematical model to determine the effect of relevant factors on the coefficient of the online ash monitor, which revealed the relationship between coal composition and the parameters of the ash monitor, ensuring the stable and accurate measurement of ash in clean coal. The method of determining parameters used in the case of coal blending... [more]

Sour water stripping can treat the sour water produced by crude oil processing, which has the effect of environmental protection, energy saving and emission reduction. This paper aims to reduce energy consumption of the unit by strengthening process parameter optimization. Firstly, the basic model is established by utilizing Aspen Plus, and the optimal model is determined by comparative analysis of back propagation neural network (BPNN), radial basis function neural network (RBFNN) and generalized regression neural network (GRNN) models. Then, the sensitivity analysis of Sobol is used to select the operating variables that have a significant influence on the energy consumption of the sour water stripping system. Finally, the particle swarm optimization (PSO) algorithm is used to optimize the operating conditions of the sour water stripping unit. The results show that the RBFNN model is more accurate than other models. Its network structure is 5-66-1, and the expected value has an appro... [more]

For the reduction in the electromagnetic noise level of three-phase induction motors, many empirical rules and analytical models have been established to select the matching scheme of pole and slot, but they are not fully applicable to five-phase squirrel cage induction motors (FSCIM). In this paper, combined with the slot-number phase diagram (SNPD), and the electromagnetic force-vibration-acoustic analytical model deduced in Part I, the influence of pole-slot schemes, including five-phase regular-size phase-belt and fractional-slot winding, on magnetic noise is analyzed. The feasibility of electromagnetic noise prediction is verified by finite element simulation and experiments. Taking a 4 kW FSCIM as a prototype, noise prediction is carried out for all the slot-number matching schemes with pole pairs not exceeding three. For two noise reduction targets, which reduce the maximum single-frequency noise in the steady-state operation and the average noise during startup, the pole-slot n... [more]