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Air-based photovoltaic thermal(PVT) solar collectors can convert solar energy into both electrical and thermal energy. However, the output efficiency was often low due to the limitation of the heat transfer capacity for air. Therefore, in this paper, an air-based PVT with the application of a novel rib was modeled and numerically simulated. The innovation of this paper was proposing a novel rib, which was based on the Venturi effect. First, the effects of the new rib control parameters on the performance of the PVT system were analyzed using orthogonal design tests. The result showed that the thermal efficiency of the best factors combination test was 51.16% when the solar radiation was 500W=m²and the air inlet rate was 0:09m=s. Second, analyzing the fluid flow characteristics and the enhanced heat transfer mechanism, this study found that the increased air velocity under the novel rib and the low-velocity vortex formed between the rib both negatively affected heat transfer. Consequently, this paper proposed a novel fin design coupled with curved fins to address the issues with the novel rib design, which achieved 55.12% thermal efficiency with the combination structure. Finally, we applied the combined structure to the PVT system, studied its thermal efficiency under real-world conditions, and compared it with the empty channel collector. The results showed significant improvement, with a 16.38% increase in thermal efficiency and the model exhibited excellent, stable performance. [ABSTRACT FROM AUTHOR]

Reducing greenhouse gas emissions or collecting and converting existing greenhouse gases has become a global concern. One of the most effective methods of utilizing CH4 and CO2 resources is the dry reforming of methane (DRM). Transition metal carbide catalysts have attracted wide attention because of their excellent catalysis performance and carbon deposition resistance. However, pure-phase carbides are easily oxidized and deactivated at atmospheric pressure in DRM reactions. There is a problem of poor dispersion (Mo2C 17 m² /g). Therefore, this paper summarizes the effects of adding active sites and supported carbides on the DRM reaction, discusses the role of active sites and supports in the catalyst, and introduces the different preparation methods of transition metal carbides. This paper also reviews the catalyst mechanism of transition metal carbides in DRM reactions. Nevertheless, the current research in this field needs to be deepened. Therefore, it is necessary to strengthen the exploration of various catalyst preparation methods and mechanisms, so as to realize future improvement in this field. [ABSTRACT FROM AUTHOR]

Coalbed methane, also known as coalbed methane gas, is a natural gas formed by the biogeochemical and pyrolysis processes during the formation and evolution of coal and stored in coal seams. Compared with conventional coalbed methane, deep coalbed methane has a rich resource and is an important substitute for natural gas increase, storage, and production. During the process of coalbed methane extraction, the inability of coal rock to bond well with cement slurry leads to a decrease in the quality of cementing, which has become one of the main problems affecting the extraction of deep coalbed methane. To address this issue, this paper first analyzes the microstructure of the coal rock-cement interface to reveal the mechanism of strengthening the coal rock-cement interface bonding. Then, using the wettability of coal rock as an evaluation index and the surfactant wetting modification method, the paper modified the surface of coal rock to enhance its hydrophilicity, optimized the suitable coal rock wetting modification agent, and finally evaluated the enhancement effect of the coal rock wetting modification agent on the quality of the coal rock-cement interface bonding through interface bonding experiments. The research results indicate that the hydrophobicity of coal rock surface is the main reason for the poor bonding between coal rock and cement. The three primary surfactants can improve the water wettability of coal and rock surfaces by 41.57%–52.95%, among which AES surfactant has the best improvement effect. After soaking in 0.5% AES solution at 85°C for 8 min, the hydrophilicity of coal rock can be increased by 72.3%. There are no obvious cracks between the coal rock-cement interface, and the bonding quality of the coal rock-cement interface has increased 2.69 times. Coal rock surface wetting modification can effectively enhance the interface bonding effect, which is conducive to improving the quality of cementing of deep coalbed methane. [ABSTRACT FROM AUTHOR]

At present, the number of electric vehicles is increasing day by day. The full integration of electric vehicles and multi-energy coupled integrated energy systems is the future development trend. This paper introduces a novel form of flexible energy storage in the integrated energy system ;(IES): electric vehicle (EV). And It proposes that mixed natural gas hydrogen be used as the primary energy source for IES, which replaces traditional natural gas. Combined with the above, the IES is scheduled to meet the system’s multiload for heating, cooling, and electricity demands. Based on the integrated energy system’s structure and energy conversion principles, a robust twostage optimization model for the IES is proposed to minimize the daily operation scheduling costs. The proposed model considers the uncertainty of distributed renewable generation and flexible energy storage. Uncertain adjustment parameters are introduced into the model, which can flexibly adjust the conservatism of the scheme. Using the column and constraint generation algorithm (C&CG) and the strong duality theory, the model presented in this paper is solved and the optimal scheduling scheme is obtained. The final simulation results validate the effectiveness of the model and algorithm. The addition of flexible energy storage and mixed natural gas hydrogen effectively improves the economy and flexibility of the system while reducing carbon emissions costs. Consideration of uncertainty improves system robustness and safety. In addition, sensitivity analyses of the influence of the proportion of hydrogen mixed with natural gas, the setting of uncertain adjustment parameters, electricity prices, weather, and load fluctuations on system operation. The results show that compared to existing research, electric vehicles as a flexible energy storage device and mixed natural gas hydrogen supply, increase the economic benefits of IES by 19.8% and 23%, respectively. [ABSTRACT FROM AUTHOR]

This research introduces an innovative analytical framework for studying the behavior of electric vehicles (EVs) in power grids. The approach primarily examines the dynamic State of Charge (SOC) and energy reserves of EV batteries. By thoroughly examining patterns of EV charging demand and operational states (charging, discharging, idling, and waiting) across various time intervals, including day and night periods, this study aims to provide a comprehensive understanding of EV dynamic behavior in power networks. The proposed model goes beyond traditional assessments by incorporating human behavioral patterns and responsiveness to economic signals, specifically investigating the impact of electricity pricing on user behavior. The core analysis centers on exploring the Vehicle-to-Grid (V2G) concept, viewing EVs not only as energy consumers but also as potential contributors to grid stability and efficiency. The study delves into how the interplay of dynamic EV behavioral characteristics and owner responses to pricing influences the overall energy consumption curve of the grid, thereby shaping the capability of EVs in providing grid support services. To quantitatively validate the effectiveness of the model, a detailed case study is conducted, offering empirical evidence of its practical utility. The research findings are quantified, highlighting the significant implications for decision-makers, grid managers, and stakeholders in the energy sector. The paper emphasizes the main outcomes, demonstrating how the proposed analytical framework can empower stakeholders in making informed decisions about policy and infrastructure development. The robust methodological approach presented in this paper serves as a valuable tool for evaluating the impacts of adopting V2G, providing strategic insights for a more sustainable and economically viable paradigm [ABSTRACT FROM AUTHOR]

Energy generation systems based on FC (fuel cell) are viewed as a viable substitute for those that simply rely on thermodynamic cycles in the power production field. In this paper, a 10-stack SOFC systems performance and optimization of that utilizing a newly improved optimizer known as the Fractional-order Kho-Kho optimization method will be presented in this paper. The multi-objective optimization approach is applied in the optimization phase to achieve the desired performance goals for the SOFC system. With the help of this technique, the desired system can be optimized in accordance with two objective functions: first, the electric power of the system can be maximized, while the equalized price of the electricity produced is minimized. Then, the electrical efficiency of the system can be maximized, while the equalized price of the electricity produced is minimized. The results show that, by reducing the coefficient and increasing efficiency, optimal solutions were achieved with higher electricity prices. It is observed that an increase in energy prices led to a 9% increase in productivity, whereas a 15% increase resulted in only a 2% increase. The findings demonstrate that multi-objective optimization may be used as a sophisticated analytical tool as well as a guiding element for decision-makers utilizing such a system. [ABSTRACT FROM AUTHOR]

At present, electricity demand and pollution are the main concerns all over the world. With the help of this paper, a small contribution to energy production and pollution in the environment can be reduced. Exhaust Fan Cum Micro Wind Turbine (EFCMWT) is used for power generation. In this paper, I study a novel approach of EFCMWT for power generation. It has been installed at a height of 14.11 m at the windows near the toilet in a high rise building at Kosi Hostel NIT Patna. The EFCMWT generates power at a height of 14.11 m in the building. With respect to wind speed, various parameters are analyzed, such as how much DC voltage is generated, how much DC current is generated and also it is analyzed that how much EFCMWT power is generated and tip speed ratio variation with respect to wind speed. On windows where EFCMWT is installed, place anemometer near EFCMWT and analyzed wind power. The power coefficient with respect to wind speed is also analyzed for EFCMWT. Maximum DC voltage is 16 V, maximum DC current is 0.076 A, tip speed ratio is 0.45 and maximum EFCMWT power is 1.216 W which is achieved at wind speed of 7 m/s. [ABSTRACT FROM AUTHOR]

In this paper, anthracite in Shanxi region is taken as a research object, and the pore structure of coal under different freeze-thaw times is characterized and analyzed by scanning electron microscope and nitrogen adsorption experiment. The SEM experimental results show that the micron-scale cracks on the surface of anthracite gradually connect after freeze-thaw, and the secondary crack channels are formed around the pores and air holes, so that the pores also begin to connect. Further, the quantitative information of the picture was extracted, and it was found that the surface porosity and fractal dimension of the coal sample changed significantly after three freeze-thaw cycles, which increased by 163.3% and 15.9% respectively, and increased with the increase of freeze-thaw cycles. The results of low-temperature nitrogen adsorption experiments show that the coal samples after freeze-thaw are mainly crack, and the pore structure changes from simple to complex. In addition, the maximum nitrogen adsorption capacity, specific surface area and pore volume increased by 125.7%, 69.3% and 72.6%, respectively. With the increase of freeze-thaw times, the growth rates of maximum nitrogen adsorption capacity, specific surface area and pore volume are significantly different. The results of joint characterization show that the number of pores and cracks increases to different degrees after freezing and thawing. Comparing the increase in the degree of fracturing (163.3%) with the increase in the total pore volume (30.68%), we find that the degree of change of the crack after thawing is higher than that of the pore. In this paper, the damage effect of coal samples after freezing and thawing with liquid nitrogen is investigated from an experimental point of view, which accelerates the great leap of cyclic cryogenic fracturing technology from basic theory to technical practice. [ABSTRACT FROM AUTHOR]

For the development of renewable energy generation as a viable alternative to fossil fuel-based generation, solar power has received widespread acceptance. An increase in solar power usage can mitigate the impact of climate change, energy demand, and cost-effective dispatch. To use solar power efficiently and ensure grid consistency, reliable and accurate forecasting of information becomes very crucial. Hence, the main purpose of this work is to get the best suitable solar irradiance forecasting model and to implement the forecasted solar power to the designed hybrid battery swapping stations. Each year, new techniques and approaches are used to improve the model accuracy with the critical aim of lowering the variability of predictions. This paper takes a close look at different deep-learning methods to predict solar irradiance for a certain period of time. The real-time time series data is used, and for analyzing the time series data, the statistical ARIMA model, LSTMbased RNN technique, and Dual Attention-based Recurrent Neural network have been used. These models are implemented using Jupyter Notebook with Python programming language. To analyze the efficiency and evaluate the performance of real-time data of the models, a comparative study has been done on the different error metrics. This paper reveals that the LSTM model is providing the best solar power forecasting with the least error metrics like MSE of .0091, MAE of .0525, RMSE of .0953, and MSLE of .0047. [ABSTRACT FROM AUTHOR]

Advancements in electric vehicle (EV) technology and integration of renewable energy systems into EV has emerged as a transformative standard for sustainable and efficient transportation have led to the widespread adoption of Permanent Magnet Synchronous Motors (PMSMs) for vehicle drive system. The CAGR Analysis 2023–2030 predicts an 11% annual growth rate for the global electric vehicle industry. This review paper comprehensively explores the multidimensional aspects of inverter-based integration, highlighting their significance in enabling seamless hybrid renewable energy utilization and uninterruptedly charges the EV batteries which delivers an opportunity to optimize the drive process of PMSM effectively. A relentless torque is extremely essential in the electric vehicle applications to attain efficient motor speed. This review paper sights the various aspects of inverter fed PMSM drive controller along with a hybrid Photovoltaic (PV)-dynamo input source system and discusses the development of a productive EV battery charging structure. The findings suggest that the combination of PMSM motors along with a hybrid PV-dynamo source can significantly enhance the charging efficiency by 97% and improve overall PMSM performance. A comprehensive overview of renewable energy-powered EVs and their role in reshaping the future of sustainable mobility. [ABSTRACT FROM AUTHOR]

This paper focuses on the performance of Molybdenum-vanadiumphosphorus heteropolyacids (PMo12-xVx) with different V-doped amounts in catalyzing the conversion of lignin to bio-oil, and the distribution of liquefied products. Molybdenum-vanadium-phosphorus heteropolyacids (PMo11V1, PMo10V2, PMo9V3) with different amount (0, 2.5, 5, 10 wt%) were used to catalyze lignin liquefaction. The experimental results showed that PMo12-xVx could effectively catalyze the depolymerization of lignin to bio-oil, and the doping amount of the V atom in PMo12-xVx affects the distribution of lignin depolymerization products. The highest bio-oil yield (53.62wt%) and conversion (57.83wt%) could be obtained from lignin liquefaction at 2.5 wt% PMo9V3. With the increase of PMo12-xVx V-atom doped amount, the content of aliphatic hydrocarbons increased from 3.14% to 40.58%, the content of vanillin increased from none to 8.9%. Based on the analysis of bio-oil, FT-IR data, and DFT simulation results, it was found that the selective cleavage of the Cα-Cβ bond and the ring-opening of the carbon at the methyl end of lignin were the main reasons for the high yield of vanillin and aliphatic hydrocarbons during the depolymerization of lignin catalyzed by PMo12-xVx. Finally, a possible reaction pathway for the PMo12-xVx-catalyzed depolymerization of lignin to vanillin and aliphatic hydrocarbons was proposed. [ABSTRACT FROM AUTHOR]

The reliability of the microgrid supply is often relying on the energy storage mediums used. Hydrogen is considered as a long-term energy storage solution whereas battery provides the energy for short-term. Fuel cell converts the stored hydrogen energy into electricity. As these storage mediums have low inertia in the system, there can be excessive current stress on the devices, leading to degradation. Virtual inertia can improve the behavior of the devices during load variation. These storage devices can be modeled as virtual machines, and these virtual inertia-based devices can provide a delayed response to the load variation. Therefore, the life of the storage mediums can be improved. In this paper, a DC microgrid system has been studied, having the photovoltaic power generator, battery, supercapacitor, and fuel cell as the other power sources. The photovoltaic generator works in MPPT mode and generates electricity to meet the load demand. The virtual inertia-based control embedded with each kind of storage medium enables the limitation of the sudden variation of power. The fuel cell provides the rated power with a certain delay w.r.t. battery and supercapacitor so that it has less dynamic power stress. The sudden variation in the load demand is met by the supercapacitor, and the battery provides the remaining power owing the high inertia as compared to the supercapacitor. The power allocation among each kind of storage medium takes into account the hydrogen storage state of charge also. The simulation results have been obtained by using the OPAL-RT to verify the effectiveness of the control strategy in real-time. The rate of power change for the fuel cell is achieved as ≈ 160 W/s. Whereas the rate of power change of the battery and supercapacitor are found to be ≈ 321 W/s, and ≈ 626 W/s, respectively. The DC bus voltage is well regulated to the nominal value in the transient load condition. [ABSTRACT FROM AUTHOR]

There are many oily sludge treatment technologies with great development prospects, and due to the lack of an objective and scientific technology evaluation system, there have been different opinions and views on the selection of technologies. To address this issue, this paper establishes a multicriteria decision system based on hierarchical analysis and gray decisionmaking, discusses the weights of oily sludge treatment technologies in terms of economic benefits, technology, environment and social indicators, and categorizes the relevant impact indicators into target level, criterion level and program level, etc. So as to analyze them qualitatively and quantitatively. The results show that in the hierarchical analysis decision system, the order of influence of the weight of each indicator on the research objectives is as follows: technical and environmental impact indicators occupy an absolute advantage for the treatment and disposal of oily sludge, with a weight of 0.5886 for environmental indicators and 0.2074 for technical indicators, whose main impact indicators include the resourceization of oily sludge with a weight of 0.6104 and the pollution degree of soil with a weight of 0.5115. Because X2 shows a high correlation in the evaluation model, the preferred oily sludge and blast furnace slag catalytic pyrolysis treatment, a comprehensive evaluation of oily sludge treatment technologies will help researchers to have a good understanding of the recent developments and future research directions. [ABSTRACT FROM AUTHOR]

In recent years, notable advancements have been achieved to increase the kesterite CZTSSe solar cells efficiency. The maximum experimental efficiency measured is approximately 13.6%. Compared to other (TFSCs), the current CZTSSe exhibits a low efficiency caused by a significant shortage in opencircuit voltage, and the power conversion current value is still largely lower than the Shockley-Queisser limit (28%). In this regard, this research paper presents a numerical study of CuZnTnSSe solar cell in concentrator application combined with BSF layer to improve its efficiency by using SCAPS-1D software. The solar cell is composed of ZnO/CdS/CZTSSe/Mo arrangement. Firstly, simulation and experimental published data were used for model validation. SnS layer incorporation as back surface field (BSF) results in enhancing its efficiency from 12.54% to 15.84%. Furthermore, BSF and absorber thickness and doping concentration have been optimized, resulting in an efficiency of 20.17% under ideal circumstances. The improved CZTSSe solar cell efficiency rises from 20.17% to 24.10% at 10 suns concentration when the concentrator effect is further examined. Finally, a practical test using a silicon (Si) solar cell with an 8X concentration Fresnel lens was conducted to validate the simulation approach. A similar pattern is shown under the concentration effect in both the simulation and experimental solar cells. The resultant conclusion offers insightful information about the utilization of CZTSSe solar cells in concentrators applications, especially when combined with (BSF) layer. [ABSTRACT FROM AUTHOR]

Carbon emission reduction is an important part of regional low-carbon economic development. In this paper, gray correlation analysis, neural network model, Gaussian multi-mode fitting and other methods were used to analyze the relationship between total carbon emissions and regional economic development, industrial structure, and energy consumption in Henan Province. On this basis, the future development of carbon emissions is predicted. The calculation results showed that the correlation between the three industries and carbon emissions in Henan Province is more than .7, among which the secondary industry has the highest correlation (.77). In the secondary industry, the correlation coefficient between coal and carbon emissions is the highest .87, while the correlation coefficient between other energy sources is about .5. In the neural network prediction model, the correlation coefficient between the prediction curve and the actual total carbon emission curve is .989, and the prediction results have a good degree of fit. The carbon emission prediction curve was divided into two parts: a linear decline stage from 2018 to 2024, and a rapid decline stage after 2024.The results showed that more efforts should be made in industrial structure, energy consumption structure and environmental protection to achieve low-carbon development in Henan province. [ABSTRACT FROM AUTHOR]

In order to improve the aerodynamic characteristics of small wind turbine blades, a new form of flow control was investigated in this paper. Which was the addition of an S809 airfoil profile slat on the leading edge of blade and a Gurney flap on the trailing edge of the blade. The effects of dual control method on the aerodynamic characteristics were discussed through numerical simulations method. The findings showed that this dual control method increased the fluid velocity on the suction surface of the blade. The fluid could receive higher energy to suppress the inverse pressure gradient in the boundary layer. The blade torque had a significant influence by the dual control method, the total torque of the blade was greatly increased compared to the original blade. The main blade torque of blade-1 was increased by 180.21 N⋅m compared to the original blade at 15.1 m/s. The pressure difference was also increased and the flow separation was restrained, especially near r/R = 0.6. At 10 m/s, the torque coefficients of the r/R = 0.5–0.7 spanwise cross-section were improved by the dual control method. When wind speed was 20.1 m/s, blade-3 increased the torque coefficient from 0.84 to 1.89 at r/R = 0.3 compared to the blade-0, an increase of 125%. [ABSTRACT FROM AUTHOR]

With the increasing temperature and pressure in the cylinder of the diesel engine, the in-cylinder environment gradually exceeded the thermodynamic critical point of hydrocarbon fuel. Compared with subcritical spray, the phase transformation mechanism of supercritical spray is essentially changed. In this paper, the n-heptane fuel sprays in three conditions case 1 (T1 = 400 K P1 = 2 MPa), case 2 (T2 = 600 K P2 = 2 MPa), and case 3 (T3 = 800 K P3 = 6 MPa) were obtained by high-speed digital schlieren method on the test platform of a constant volume combustion bomb. The spray liquid phase, liquid–gas mixed layer, and mixture were divided, and the variation rules of the spray cone angle, the liquid phase length, maximum interface thickness, and liquid– gas mixed layer area were discussed. The results showed that the higher the ambient temperature and pressure, the more severe the fragmentation of the spray. Compared with the subcritical condition, the spray penetration distance in the supercritical condition tended to be flat faster. Compared with 400 K, 2 MPa condition, the spray cone angle was about 33° and 50% larger at 800 K, 6 MPa condition. The liquid core area at 800 K, 6 MPa condition was 60 cm², reduced by 75% compared with 400 K, 2 MPa condition, resulting in better spray diffusion and mixing with atmospheric gas. The sensitivity analysis of ambient temperature and pressure on spray characteristic parameters shows that temperature has a greater impact on the interface mixing layer area (VIP = 1.23), and pressure has a greater on penetration distance and spray penetration rate (VIP = 1.23). When the environmental conditions exceed the thermodynamic critical point, the area of the liquid–gas mixed layer increases due to the transformation of spray from evaporation to diffusion and the phenomenon of interfacial layer enrichment. In summary, the supercritical condition promotes the mixing of spray and environment and has a positive effect on spray diffusion and atomization. [ABSTRACT FROM AUTHOR]

The CO2-containing natural gas is increasing, and there is an urgent need for green treatment of natural gas containing CO2 to realize the utilization of natural gas. Conventional natural gas decarbonization methods have drawbacks such as non-environmental friendliness, and the low-temperature condensation separation of carbon dioxide (snowing-separation) method as a green method of carbon capture is proposed in this paper. Aiming at the characteristics of CO2 condensation in the snowing-separation process, the growth process of CO2 crystals is obtained by simulation using the CA (Cellular Automata) method and finds that the effect of supersaturation on the growth of CO2 crystals is exponential. The snowing-separation process at .5 MPa is analyzed, and it is found that the condensation range is 158.51 K–173.86 K, the upper limit of CO2 mole fraction in natural gas is 10.1%, and the minimum separation time is 8.65 × 10−8s. Analyzing the influencing factors of CO2 separation efficiency, combining the simulation results with the experimental results, the maximum relative error is 13.93%, which can better predict the snowingseparation technology of CO2 in natural gas, and then promote the development of efficient low-temperature carbon capture process. [ABSTRACT FROM AUTHOR]

To improve the explosion suppression efficiency of porous media in natural gas hydrogen-doped pipelines, this paper designs and builds an experimental platform with dimensions of 10 cm × 10 cm × 100 cm organ transparent glass explosion pipeline and researches the synergistic effect of the use of nickel foam and CO2 to inhibit the explosion of hydrogen-doped methane with a hydrogen doping ratio of φ = 10%. Studies have shown that using a dual explosion suppression mechanism, the synergistic effect of nickel foam and CO2 acting at different jet positions has a significant inhibitory effect on the flame and overpressure of low-hydrogen-ratio methane explosions. The synergistic CO2 in porous media has a more potent inhibitory effect on the right-side wall jet than on the left-side and left-side jet. When the synergistic impact of nickel foam and CO2 acts on the right-side wall jet, the flame is quenched, substantially attenuating the overpressure peak. When the nickel foam synergistic CO2 acts on the right-side wall jet, the optimal effect is achieved when the CO2 jet pressure is set at 0.3 MPa, which successfully quenches the flame and significantly reduces the overpressure peak. However, the dual explosion suppression mechanism fails when the CO2 jet pressure is 0.2 MPa. [ABSTRACT FROM AUTHOR]

With the high proportion of new energy access and the increasing demand for load electricity, efficient and reasonable control of battery energy storage systems (BESS) in the power grid is the key to promoting new energy consumption, improving the quality and economy of power supply in the power grid. To solve the optimization control problem of BESS under multiple power service objectives, a two-stage optimization control method for BESS based on multi-service attribute utility evaluation has been proposed in this paper. Firstly, based on various power service demands and grid operation constraints, a multi-objective optimized scheduling model for BESS has been established; Then, to solve the complex coupling problem between multiple optimization objectives of BESS, a two-stage optimization structure has been designed that the changes of various service indicators under different optimization objectives have been recognized in the first stage, and the entropy weight method was used to weight each optimization objective in the second stage objectively; Finally, in the IEEE 33-bus simulation example, compared with the suboptimal result under each singleobjective method, the relative error of the power line losses, the maximum voltage deviation, the curtailment of new energy and the economics of power grid of this algorithm has been reduced at least 2.31, 1.11, 2.90, and 1.05 times, respectively. Meanwhile, the performances of active power reserve and reactive power reserve are better than most single-objective optimizations. [ABSTRACT FROM AUTHOR]

The capability of vertical axis wind turbine (VAWT) is influenced by its input parameters. In this paper, for the three-bladed VAWT with the NACA0018 airfoil, three important input parameters, i.e. tip speed ratio (TSR), airfoil chord length (C), and pitch angle (β), are selected to explore their impact on the capability of the VAWT, and then to find the best combination of them. Firstly, 16 sets of experiments are determined according to the Taguchi method and are evaluated using the 2D computational fluid dynamics (CFD) numerical simulation, and further studied with the Analysis of Variance. The consequence shows that the TSR and pitch angle are more critical to the performance of the VAWT. In order to obtain the optimal configuration of these parameters, an intelligent method is further proposed. Firstly, a certain number of design schemes are extracted in the selected space through Latin hypercube sampling (LHS), and then the torque coefficient (Cm) of each design scheme was obtained by 2D CFD simulation, the Kriging model is used to establish the correlation among the input parameters and their corresponding torque coefficient. Finally, the improved differential evolution algorithm (JADE) is used to tackle the Kriging model to get the optimal input parameter values. The results show that when the rotor diameter (D) is 2.5 m, the optimal parameters are TSR is 2.6, C is 0.227 m and β is −2.47°, the performance of the VAWT is further improved by about 4.5% compared with the optimal values obtained by the Taguchi method. [ABSTRACT FROM AUTHOR]

High-performance and low-cost emission characteristic prediction is very crucial for diesel engine design optimization and emission aftertreatment control and diagnosis. In this paper, a novel hybrid model that combines Convolutional Neural Network (CNN) and Gated Recurrent Unit Network (GRU) was proposed to predict the emission characteristic from diesel engines, encompassing CO, THC, CO2, NOx, exhaust temperature and exhaust pressure. Nine operating parameters from WHTC and WHSC cycles, including speed, torque, intake pressure, intake flow, intake temperature, oil pressure, fuel rate, oil temperature, water temperature, were considered as inputs. Firstly, the importance of each variable is evaluated by Random Forests algorithm to determine the optimal inputs for each emission characteristic parameter and reduce redundancy. Then the effect of different hyperparameters on the model performance was discussed in detail and PSO algorithm was used to obtain the optimal hyperparameters. Finally, the CNN-GRU hybrid model was assessed for its generalization and compared with ANN, LSTM and GRU models. The result demonstrates that the CNN-GRU hybrid model with PSO optimization has excellent prediction performance in either the training dataset or the validation dataset. The average value of R² is 0.993 in the training dataset and 0.985 on the validation dataset. In the test dataset, the average R² is 0.961, showing a minor decrease of 3.19% and 2.47% compared to the training and validation dataset, respectively. This indicates that the CNN-GRU hybrid model has strong generalization ability. Compared with other algorithms in the test dataset, the CNN-GRU hybrid model exhibits better comprehensive performance, with the average R² value exceeding that of ANN, LSTM and only GRU by 5.96%, 2.69% and 3.23%, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a power hardware in the loop (p-HIL) validation of a wind energy conversion system (WECS) interconnected into the balanced or unbalanced grid is presented. WECS power is obtained from wind fluctuations of the Yucatan Peninsula, Mexico, and transferred through the DC-AC power electronic converter (PEC). A robust control law based on a simple PI regulator and phasor analysis is proposed, having advantages, such as continuous power generation, operating both under balanced and unbalanced grid conditions; total harmonic distortion (THD) reduction less than 3%; power factor (PF) correction close to the unit; balanced grid currents; a simple mathematical analysis. The main objective is to keep the WECS connected to the electrical grid even in the presence of unbalanced threephase voltages, including contributions such as: i) VDC ripple reduction; ii) Balanced currents; iii) Sinusoidal currents; iv) Free of Sequence calculation; v) Free of dq0 or αβ Transforms; vi) Simple PI Loop control; and vii) Experimental Validation. The WECS efficiency and robustness are assessed by a complete mathematical examination, validated by the simulations in MATLABSimulink®, and support with experimental results through the real-time simulator Opal-RT Technologies®, a low-scale laboratory prototype, and p-HIL methodology. The results present a DC link voltage constant at 75 V and optimal and reliable power integration with an efficiency of 95%. [ABSTRACT FROM AUTHOR]

In order to mitigate the impact of temperature and irradiation variations on photovoltaic (PV) panels, it is crucial to employ the maximum power point tracking (MPPT) technique. This paper introduces a novel MPPT approach that provides a reference current, denoted as Iref, to extract the maximum power from the PV array. The difference between the input current Ipv, and Iref is then fed into a PID controller, which adjusts the duty cycle accordingly to control the Quadratic Boost Converter (QBC). The proposed MPPT approach is based on the analysis of measurement data obtained from PV panels. From this, a linear mathematical function between Iref and solar irradiation is achieved. To assess the performance of this approach, a comparative study is being carried out not only with conventional MPPT techniques such as P&O and INC-COND but also with modern techniques such as ANN, PSO, FLC, and improved P&O (IMP-P&O). The simulation results clearly demonstrate enhanced tracking performance under various test conditions, including the Step & Ropp test, as well as real profiles for both sunny and cloudy days. Certainly, the novel approach shows its ability to outperform both conventional and modern methods with a faster convergence speed (less than 2 milliseconds), the lowest steady-state oscillations (less than 0.25 Watts), and the highest tracking efficiency (greater than 99.79%). [ABSTRACT FROM AUTHOR]

In this work, a partial heat-integrated reactive distillation process was studied to yield n-propyl acetate. To optimize the operating parameters of two distinct processes, the sequential iteration optimization method was employed. The heat exchanger network (HEN) is an effective approach for the heat-integrated design of a distillation process. Compared with the conventional reactive distillation process, the total annual cost, CO2 emissions and total energy consumption of the partial heat-integrated reactive distillation process decreased by 20.7%, 31.1%, and 32.2%, respectively. The thermodynamic efficiencies of reactive distillation process and partial heatintegrated reactive distillation process were 4.33% and 9.86%, respectively. The significance of this paper is crucial in guiding the process of partial heatintegrated reactive distillation for the production of n-propyl acetate. [ABSTRACT FROM AUTHOR]

Tracking control of the oxygen excess ratio (OER) and keeping the cathode air pressure relatively stable are essential for the operation of polymer electrolyte membrane fuel cell (PEMFC). In automotive fuel cell air supply systems, the cathode air pressure and OER are usually unmeasurable parameters, which makes the air supply system control and fault analysis very difficult. To solve this problem, this paper proposes an extended state observer based on the hyperbolic tangent function (HTF-ESO) to estimate the cathode air pressure of the fuel cell gas supply system, and indirectly obtains the OER according to the estimated cathode pressure, and designs the sliding mode control (SMC) and a first-order active disturbance rejection control (ADRC) for the tracking control of the OER. The simulation results show that the improved HTF-ESO effectively mitigates the initial differential peak phenomenon and reduces the initial estimation error of the cathode air pressure, and the RMSE of the cathode pressure and supply manifold pressure observation errors are reduced by 68% and 20%, respectively, compared with the present unimproved ESO. Compared with the PI, the RSME of the control error after convergence of the designed SMC and ADRC is reduced by 4.3%, and the OER can be restored to the reference value within 1 second, with good dynamic response. [ABSTRACT FROM AUTHOR]

It is of great significance to improve the safety, efficiency, and economy of lithium-ion batteries by improving the capacity estimation accuracy of lithium-ion batteries. In this paper, feature extraction and correlation analysis are carried out on the data of lithium-ion battery charging process, and the voltage curve of constant current charging stage is extracted. The difference characteristics between each cycle are used to describe the battery capacity, and these statistical characteristics are proved to be highly correlated with the battery capacity. Furthermore, an online estimation model of battery capacity based on convolution self-attention is established, and the above characteristics of constant current charging process and the battery capacity of the latest cycle are fused as input vectors of the model to realize online estimation of battery capacity. Finally, an open data set is used to verify the model experiment. The results show that the prediction error of MAE is 0.17% and that of RMSE is 0.22%. [ABSTRACT FROM AUTHOR]

Other researchers have examined alternative methods for desalinating water in arid regions, focusing specifically on the utilization of solar energy due to its abundance and lack of negative environmental impact. Desalination is one of the many applications of solar energy, and this study proposes a novel approach that employs solar radiation to evaporate brackish and saltwater. By harnessing the heat generated by incident solar radiation on photovoltaic panels, water is able to evaporate under-controlled conditions. This paper is divided into two main sections: the first involves conducting experiments in the laboratory of Najaf Engineering Technical College, while the second entails the numerical simulation of proposed models using COMSOL Multiphysics V. 6.1 software. Previous research has demonstrated the use of heat produced on the back surface of solar cells to generate distilled water by passing non-potable water through a cotton wick attached to the back surface. The new design of the solar active photovoltaic distiller incorporates a solar photovoltaic, wick, and Peltier device. In this study, the Peltier device was employed to enhance the evaporation and condensation processes, resulting in a solar still that integrates the distillation system with the solar panel, thereby increasing productivity per unit area. The experimental and numerical results indicate that model 02 achieves a productivity of 0.827 kg/ m2 h, and 0.907 kg/m² h for flow rates of 2 mL/min and 4 mL/min, respectively. Model 02, which incorporates a Peltier device within a glass container, demonstrates higher productivity across all experimental days, with a maximum daily cumulative productivity of 4355.3 g. Furthermore, model 02 exhibits higher temperatures compared to other modules, with a maximum average back sheet temperature of 78°C in March and a minimum of 55°C. [ABSTRACT FROM AUTHOR]

A significant amount of wastewater has been produced from the oilfield extractive fluid with the development of oilfields in recent decades. Settling is the first process in the treatment of oilfield wastewater. As one of the most crucial devices in oilfield wastewater treatment, the vertical sedimentation tank has been widely utilized in the precipitation process. This work aims to explore the properties of vertical sedimentation tanks for oil-water separation and analyze related variables in the separation. First, we utilize the for-profit software Fluent for computational fluid dynamics, in which the RNG k-ε model, the multiphase flow mixing model, and the PBM model are used to simulate the internal flow field distribution in the vertical sedimentation tank under various boundary conditions. Then, the implication of changing the boundary conditions on the vertical sedimentation tanks is analyzed. It is demonstrated that by replacing the PBM model for the homogeneous particle size, the simulation of oil-water two-phase flow in sedimentation tanks is more correctly measured. The findings demonstrate that raising the operating temperature increases the oil content at the output and dewatering rate of the sedimentation tanks by 73.1%; however, above 44°C, the effect of oil removal gradually tends to deteriorate; the longer hydraulic retention time within the 8-h range, the better the effect of oil-water separation, with the best effect occurring at 8 h; and the more viscous the oil phase, the more resistance of the oil droplets to float, increasing the water phase oil-carrying capacity, resulting in a 36.5% reduction in oil content at the outlet and dewatering rate of the settling tanks. The simulation in this paper can provide theoretical direction and conference for the design of vertical sedimentation tanks, as well as improve the performance of oily wastewater treatment facilities. [ABSTRACT FROM AUTHOR]

This paper employs computational fluid dynamics (CFD) simulations with an eddy dissipation concept model (EDC) and a skeletal reaction mechanism (SK17) to analyze the impact of hydrogen addition on the premixed combustion mode of producer gas (PG) fuel in a cyclonic flow combustion chamber. The results, validated against measured wall temperature data, demonstrate a minor discrepancy between simulation and experiment. The studied result showed that injection of hydrogen into PG fuel combustion elevates the temperature of the combustion process, which can be indicated by the average temperature across the combustion chamber, outlet temperature of exhaust gas, and reactive radical species. However, increasing H2 injection over 20% results in strongly increasing CO formations. Compared to a fixed thermal input case, hydrogen injection with a variable input power resulted in a higher combustion temperature and increased emissions of both CO and NO. The maximum CO emission reached approximately 1246 ppm, while NO peaked at around 75 ppm, both observed at a 30% hydrogen injection rate. The key finding of this study revealed that direct injection of hydrogen to the combustion under the condition of a given equivalence ratio is unfavorable due to insufficient oxygen for the reaction, leading to an increase in CO emissions. The optimal condition would be a hydrogen injection below 20%, which produces low CO and NO emissions. [ABSTRACT FROM AUTHOR]

Solar photovoltaic (PV) panels and solar thermal collectors are two major technologies used to extract electrical and thermal energy, respectively, from solar irradiation. PV panels convert only 15–20% of incident solar radiation into electricity. The remaining radiation elevates the panel’s surface temperature, which badly affects the conversion efficiency and reduces the overall lifespan of the panel. Hence, in this paper, we investigate three cooling techniques developed in-house to maintain the PV panel’s surface temperature: passive cooling, active cooling, and combined cooling. A novel PV/T-PCM system was designed and fabricated to conduct a detailed experimental analysis of each of the cooling methods used on the performance of PV panel in the form of temperature and electrical efficiency of the panel. The temperature of the panel surface got reduced by a maximum of 36% at 1,050 W/m², and as an effect of that, the electrical efficiency was also improved by around 42% in the case of a combined cooling technique. Finally, empirical correlations were also developed to predict the electrical efficiency and PV panel surface temperature using the experimental data of present investigation considering investigated system and operating parameters. Based on the experimental results, the coefficient of determination (R²), for the correlation of electrical efficiency, was found to be 0.90 and 0.9188 for surface temperature that indicate good confidence level for both the correlations. As a result, the correlations and results are more important from an application standpoint for the design and development of the PV/T system. [ABSTRACT FROM AUTHOR]

Solar power forecasting is crucial in boosting the rivalry of solar power plants in the electricity markets and minimizing economic and social dependence on fossil fuels. This paper describes a method for foretelling solar power by utilizing regression approaches. The proposed regression models are developed using an actual meteorological set of data from Qassim University, KSA for one year (September 2021- August 2022). Forecasting solar power production is crucial to dealing with the smart grid’s demand and supply challenges. This research aims to make ML models that can precisely forecast solar power production. Significantly, the following noteworthy components highlight the main contributions of this work. Primarily a framework for the analysis of data is presented, and then the dataset obtained from the solar photovoltaic (SPV) system is visualized. Secondly, we evaluate the predictive capability of machine learning (ML) models employing numerous performance indices for predicting solar power time-series dataset values. According to the experimental findings, the proposed predictive approaches can lessen forecasting complexity even with a small reconstruction error. Additionally, the GBR (Gradient Boosting regression) model significantly outperformed other benchmark techniques in terms of forecast accuracy with MAPE of 0.7674, RMSE of 0.0191, MAE of 0.0132, MSE of 0.0030, and R² of 0.9723 respectively. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is a process of biochemical decomposition by anaerobic bacteria. Organic solid waste, subjected to anaerobic digestion, produces organic fertilizer and biogas, composed of methane, carbon dioxide, and other gases. The AM2 model describes the AD system and is the most widely used model for dynamic behavior analysis and control of AD processes. One of the most critical variables for system analysis is the concentration of volatile fatty acids (VFA). The behavior of the concentration of VFA depends on the dilution rate. This, in turn, depends on the performance parameters of producing and consuming VFA (k2 and k3). This paper presents a deterministic method to calculate the k2 and k3 parameters, from the dilution rate dynamics and Olson method for indirect validation of the parameters based on the direct validation of the concentration of VFA. Model results for VFA concentration showed an error of <0.4%. An error of <1.98% was found between the theoretical model and the experimental data. Overall, a global error of <2.37% gives a reliability to the proposed method to determine k2 and k3. [ABSTRACT FROM AUTHOR]

Biogas has garnered increasing interest as a sustainable alternative to fossil fuels. However, due to the complexity of generating biogas, it is crucial to adopt adequate methodologies that aid planning, building, and running operations. Mathematical models have proven to be useful for assisting in the production of biogas, and they are applicable in different stages of the process. Therefore, the objective of this paper is to investigate how mathematical models can contribute to enhancing the efficiency and optimizing the biogas generation process. The Methodi Ordinatio methodology was used to conduct a systematic review of the literature. The VOSviewer software and the bibliometrix package in R were used to generate visual maps. The results revealed that mixed integer linear programming (MILP) models are the most common, accounting for 27% of the studies, followed by simulation models (SIM) with 14%, and hybrid models (HYB) and nonlinear programming models (NLP) in equal proportions, both at 13%. These models are useful for predicting and simulating biogas production. The analysis also revealed a significant trend toward integrating biogas production with the agricultural sector. Continuous advancements and applications of mathematical models are expected to increasingly facilitate biogas generation, thereby propelling global energy usage toward a sustainable energy source. [ABSTRACT FROM AUTHOR]

This paper investigated the effects of gas pressure, in-situ stress, and coal strength on coal and gas outbursts (CGO) based on the laboratory CGO experimental data. Based on the hypothesis of the comprehensive of CGO, the single-factor control variable method was used to analyze and evaluate the relative outburst intensity, the characteristics of outburst holes, the distribution of pulverized coal, the drops of outburst gas pressure, and the pulverized coal density under different outbursts experimental condition. The improved CGO energy equation and instability criterion are proposed as a direction to study the occurrence of CGO as an energy evolution direction. Furthermore, the results shows that the initial outburst gas pressure was 0.45 MPa during the experimental conditions of in-situ stress was 5 MPa, and the coal strength was 0.24 MPa. The gas pressure is directly proportional to the relative outburst intensity, while the in-situ stress and coal strength are inversely proportional to the relative outburst intensity. After the CGO occurred, the outburst coal always show spallation and pulverization characteristics. The results highlight that the gas pressure plays a key role in pulverizing and throwing out the pulverized coal, and the in-situ stress mainly plays a role in destroying the coal, and the coal strength plays a resistance role during the CGO occurs. It is also found that pulverized coal particles size less than 0.28 mm can be used to represent the distribution pattern of the total weight of outburst pulverized coal particles in the different outburst interval. These results clearly illustrate that using effective methods to control gas pressure, in-situ stress, and coal strength has an important role in preventing and controlling CGO on coal mining sites. [ABSTRACT FROM AUTHOR]

Carbon-ash separation is a prerequisite for efficiently utilizing coal gasification fine slag (CGFS), but the enrichment characteristics of harmful elements (HEs) in the separation process are not fully understood. This paper uses gravity separation to prepare different samples, and four typical HEs (Se/Cd/ Pb/Cr) in separated products were investigated. The results showed that samples with an ash yield of 28.72%–98.86% and a specific surface area of 12.90 m2 /g-389.51 m2 /g were obtained through gravity separation. The highly volatile element Se was enriched in the C-C/C-H structure of residual carbon under the catalysis of acidic gases. The nonvolatile element Cr was encapsulated by low-melting-point minerals and remained in the minerals. The semi-volatile element Cd/Pb was easily enriched in a particle with a high specific surface area/large pore volume, especially in porous residual carbon, with an enrichment factor as high as 7.0 and 4.0, respectively. The leaching risk analysis of sorted products indicates that the products were not suitable for direct landfill; however, besides honeycomb porous carbon, other highly specific surface area products can be safely used for soil improvement. The results of this study are expected to provide a reference for the classification and utilization of CGFS and the control of HE pollution. [ABSTRACT FROM AUTHOR]

Dynamic compressive parameters of coal specimens were driven not only by impact velocities, but also by preloaded confining pressure, and impact loading methods. This paper investigates the influences of dynamic parameters based on the split Hopkinson pressure bar (SHPB) experimental data obtained from the dynamic compressive impact tests on 12 coal specimens under four different impact velocity. The analysis of the experimental results confirmed that with an increase of dynamic velocity, and then the dynamic compressive strength is constantly increases. When the dynamic velocity is 8.10 m/s, and then reacheed the maximum dynamic strength of 25.11 MPa of the coal specimen. Furthermore, the dynamic velocity of 8.10 m/s was defined as the threshold value of the dynamic strength increased. The greater of dynamic velocity, the higher degree of fragmentation of the coal specimens. The transmitted energy, reflected energy, and absorbed energy of coal specimens shows a directly proportional relationship with the incident energy. The results highlight the first and second dynamic deformation moduli can clearly explained the deformation laws of elastic and plastic stages of the coal specimens. It is also found that the maximum of strain rate is 177.28 s−1 and the maximum ultimate strain is 2.47 × 10−2of the coal specimens. The research results were beneficial to supplement the coal-rock dynamics theory, thus also providing a direction for safety and effective mining and crushing in coal mines. [ABSTRACT FROM AUTHOR]

This paper thoroughly reviews the influence of protuberances on the performance of a wind-turbine blade in terms of aerodynamic characteristics, power generation capability, and noise emission. It is observed that the protuberances are significantly useful in improving the aerodynamic performance of wind turbine blades, especially in the post-stall regime and during fluctuating wind conditions, such as wind gusts. The protuberance amplitude was found to be the dominant parameter to influence the blade performance. The amplitude and wavelength were tested in the range of 2–12%c and 2–50%c, respectively. The highest wind turbine performance was observed at small amplitude and large wavelength in the pre-stall regime and at large amplitude and small wavelength in the post-stall regime. Incorporating leading edge protuberances may increase lift and power coefficients by 50 and 55%, respectively, and reduce noise emission by nearly 16 dB. With the increase in the angle of attack, the instability noise was found to change its form. The broadband noise forms at a lower angle of attack (~2°) which converts to the tonal noise at the angle of attack, 6.5°. The protuberances substantially alter the boundary layer flow, subsequently modifying the pressure and velocity field over the suction surface of the blade. A pair of vortices forms across a protuberance, which exchanges momentum with the boundary layer flow and helps delay/eliminate the flow separation. This flow separation control is responsible for the benefits as mentioned above. [ABSTRACT FROM AUTHOR]

In order to explore the influence of pickling on the pyrolysis characteristics and adsorption performance of biomass, this paper used pickled rice husk as raw material, and used TG-FTIR coupling instrument to explore the pyrolysis characteristics and product changes of rice husk; The Coats-Redfern (C-R) method was used to analyze the pyrolysis kinetics, and the adsorption performance of pyrolysis biochar on heavy metal Cu was investigated. The results show that pickling can effectively reduce AAEMs, change the pyrolysis path, increase the release of volatiles, and increase the calorific value of raw materials by about 17.10%. The surface of rice husk retains abundant functional groups, and the vibration of characteristic peaks is more intense. The C-R kinetic analysis showed that the pyrolysis process was consistent with the reaction order n = 1, and the influence on the activation energy of rice husk was sulfuric acid > phosphoric acid > nitric acid. The pickling pyrolysis biochar can promote the adsorption of heavy metal Cu2+ in the aqueous phase, the adsorption capacity is up to 41.4 mg·g-1, and the adsorption efficiency is up to 82.8%. [ABSTRACT FROM AUTHOR]

Savonius-like hydrokinetic turbine (SAHT) in low-speed flow streams of perennial rivers is not much explored. In this paper, a triple-bladed double-stage SAHT is designed, and its performance is investigated for low flow speeds within 0.45-0.65 m/s under the effect of blade overlapping (within 10-20% in each stage), turbine diameter (within 208-234 mm), and without and with space between the stages (5.0 mm) at different operating speed ratios. Different combinations of design and operating input parameters are studied to obtain a reliable assessment of SAHT performance. After analyzing the results, the best conditions of input parameters and output performance parameters are reported in their nondimensional forms for future use of the obtained results. The torque produced by the turbine increased with the applied brake load, leading to its maximum value at the highest brake load 0.83 times the maximum load. The highest coefficient of performance is obtained as 0.086 at a space 0.25 times the maximum space (i.e. 20 mm), overlapping 15%, brake load 0.83 times the maximum load, tip speed ratio 0.276. And for this, the corresponding power 0.85 times the maximum power (i.e. 0.201 W) at free-stream flow speed of 0.85 times the maximum flow speed (i.e. 0.65 m/s) is obtained. The present turbine with space and overlapping exhibits better performance than some available SAHT designs of single/double stage, two-blade/multi-blade with/without overlap configurations. The novelty of the work is that an improved SAHT has been developed for low-flow speed perennial river applications in the band of low tip speed ratios by combining design conditions like double-stage, space between stages, and overlapping. [ABSTRACT FROM AUTHOR]

In this paper, the drying process of plantain bananas from Democratic Republic of Congo (DRC) is investigated under two climatic operating conditions, the sunny and the confined oven environments. First, the effect of these environments at 40°C on the process evolution in terms of moisture content, particle size distribution of dried bananas and phytochemical properties (color, composition) is pointed out. Obtained results essentially show that natural sun drying is more favorable for all banana slice thicknesses used. The moisture content of plantain is reduced by 57.2% for natural drying in 28 h, while it is lowered by 52.76% for oven drying in 29 h. Phytochemical composition not detected for fresh bananas features an important quantity of sugar (433,4 ± 4,9 mg/g glucose) for sunny dried bananas and (60,8 ± 0,7 mg/g glucose) for oven drying. In contrast, the total polyphenol contents obtained using natural drying is less (1,78 ± 0,05 mg/g eq GA) and (3,05 ± 1,0 mg/g eq GA) for oven drying, even though the total lipids are mostly similar in both configurations (0,12 g/100 g) for natural drying and (0,13 g/100 g) for oven drying. Considering the impact of banana slice thickness, the use of small thicknesses is more affordable. Finally, the gathered data are used to fit in selected mathematical models for thin layer drying. It turns out that the models by Page (MR = exp(−0,1838t0,9795) and MR = exp (−0,5611t0,0025)) are the best fit to explain the moisture transfer in the DRC banana in the confined oven and in the natural sun environments, respectively. These results are novel as they determine for the first time the drying characteristics of the DRC plantain bananas (abb DRC) while providing their drying kinetics in the two environments under consideration. [ABSTRACT FROM AUTHOR]

In this paper, a local isolated yeast strain was studied for bioethanol production using protein-free cheese whey powder (CWP) in batch alcoholic fermentation experiments. Ethanol tolerance tests were performed with different ethanol concentrations (from 0% to 20%). The maximum ethanol tolerance obtained for our strain was 5% (v/v). The influence of initial lactose concentration, temperature and pH on fermentation kinetic was studied. For initial lactose concentration ranging from 57.5 to 260 gL-1, the highest ethanol production 34.8 gL-1 was obtained at 109 gL-1 initial lactose concentration corresponding to 0.413 gg-1 ethanol yield (YP/S); (While it was noticed less ethanol production, namely 0.178 g g-1) at a higher initial whey sugar concentration of 260 gL-1. The effect of the initial pH on the fermentation was studied at three different values: 3, 4 and 5. The ethanol production reached a maximum of 22 g L-1 with a lactose consumption of 77.62% at pH 4. However, an observed decrease occurred in ethanol production and lactose consumption at pH 3, with values of 10.34 gL-1 and 24.46%, respectively. For the fermentation conducted at the three temperatures of 37°C, 40°C and 43°C, the maximum ethanol production and lactose consumption were 34.82 gL-1 and 80.75%, respectively, achieved at 37°C. The experimental data was analyzed using the Gompertz model to obtain the following kinetic parameters: the maximum ethanol concentration (Pm) was found to be 36.97 gL-1, the maximum ethanol production rate (rp,m) was 0.402 gL-1h-1 and the lag phase (tl ) was 10.8 h. The comparison of the isolated Kluyveromyces marxianus TXID4911 strain with the reference strain Kluyveromyces marxianus DSM 5421, showed a relatively close ethanol yield (YP/S) 0.415 and 0.505 gg,-1 respectively [ABSTRACT FROM AUTHOR]

Borehole imaging, one of the main methods of rock formation detection, is widely used in mining, tunnels, petroleum, and other fields of engineering. However, the method of manually identifying the characteristic of rock formation based on borehole imaging is greatly affected by subjective factors. For example, it should be noted that when the rock layer color is similar, the position of the rock interface may be different. In this paper, a method of quantitatively describing the characteristics of the rock formation is proposed, and the automatic recognition of the rock interface is realized. Firstly, the calculation method of rock dip angle and position based on borehole image with 360° wall surface development is proposed. Secondly, the three-dimensional distribution characteristics of the gray values of the rock layer are used to quantitatively describe the characteristics of the rock layer. Finally, an automatic recognition method of rock formation interface based on change-point detection algorithm is proposed. In addition, the recognition effect of the rock formation interface is analyzed by experiments and applied in the field. Research shows that, compared with method two, method one can determine the rock inclination. But its anti-interference ability is poor. Method two can better determine the position of the rock interface. The method is of great significance to the intelligent development of the borehole imaging system and promotes safe, efficient, and sustainable mining in coal mines [ABSTRACT FROM AUTHOR]

Worldwide, drinking water shortages are a major concern. In many parts of the world, fresh water sources are deteriorated and polluted by human activities and population growth. Using fossil fuels to distill water for human consumption requires a large amount of energy. It was suggested that solar energy could be used to distill polluted or salty water without harming the environment. The sun is a free and abundant energy source, especially in swampy and remote regions. However, the design and operation of solar stills limit their efficiency and productivity. Solar freshwater production systems are discussed in this review in terms of the latest developments in production and distillation efficiency. Based on various performance criteria, the study analyzes direct solar desalination processes. Detailed discussions of recent modifications and innovations are also included and highlighted in this paper. It is the goal of all the studies reviewed to achieve maximum productivity and efficiency, low capital costs, and ease of installation. Among the developments reviewed are phase change materials (PCMs), nanoparticles, and solar reflectors with high efficiency. In addition to features of solar stills, current modifications have been evaluated in terms of location, water temperature, solar radiation intensity, production level, inclination angle, productivity, and efficiency. Solar still performance parameters were also studied in relation to modifying the absorption area and using reflectors and condensers. Several improvements were made which resulted in high productivity rates. The distiller’s productivity increases from 10% to 180% when a phase change material is added. When a nanomaterial is added to paraffin in the still, productivity increases by 25% to 320%. Furthermore, Wicks increase the still’s yield by 20%-300%, depending on design. A few recommendations are made regarding future work in solar desalination based on this review at the end of the study. [ABSTRACT FROM AUTHOR]

As a key factor, it is vital to mathematically model the electrical efficiency of photovoltaic (PV) systems. This paper investigates the efficient modeling of a 2.5 kW grid-connected PV system, located in Mahan, Kerman, Iran, with respect to different factors like solar radiation, humidity, dust deposition, temperature, and shading. For this aim, different nonlinear models are considered and a curvefitting approach is used to optimally determine the unknown parameters. Over the case study, simulation results show that when the dust deposition is not included in the modeling (solar radiation, ambient temperature, cell temperature, humidity, and shading as inputs), the third-degree polynomial model leads to more accurate result than the other models. By use of the third-degree polynomial model, the value of root mean square error (RMSE) for train and test data sets is obtained 0.0123 and 0.0109, respectively. In this case, the average RMSE value is 0.0116. On the other hand, when dust impact is included in the modeling (solar radiation, ambient temperature, humidity, and number of dusty days as inputs), the accuracy of the exponential model is more than the other ones. In this case, the value of RMSE for both train and test data sets is obtained 0.0018. Sensitivity analysis shows that the system efficiency depends mainly on the radiation, cell temperature, and dust and less on the humidity. [ABSTRACT FROM AUTHOR]

Most hydraulic excavators use passive power control to adjust the engine speed according to the load torque to achieve power matching, which has very limited effectiveness in energy saving. In this paper, an active power optimization control of speed closed-loop engine is proposed to improve its tracking performance for the dynamic energy-saving operating points. The inertia movement of the engine during variable speed control is analyzed to determine the kinetic energy requirements for different start and end operating points. An RBF-based neural network controller is designed based on power optimization to actively compensate the strong hysteresis of the engine speed relative to the optimal torque. The simulation and the experimental results show that the proposed control method has a much faster response for the energy-saving operating points, which reduces the energy consumption by 9.28% and 5.56% without adding any energy storage devices to the hydraulic excavator. [ABSTRACT FROM AUTHOR]

Currently, heavy metal pollution is a challenge that needs to be solved urgently, and there is a broad prospect for food waste(FW) utilization. In this paper, activated hydrochar (AHC) made from FW according to actual proportion was produced by hydrothermal carbonization (HTC) and activated with K2CO3. The effects of the AHC on Cu(II) adsorption were investigated using static adsorption experiments. The results indicated that the sample fabricated at 160°C (FW-160) for 6 h had the best adsorption performance with the maximum adsorption amount of Cu(II) (36.77 mg/g). The oxygenated functional group on the surface of FW-160 was observed. The pseudo-second-order kinetic model fitted the experimental results better, which proved that chemisorption was the main adsorption mechanism, and the surface complexations, including oxygenated functional groups, were the predominant factors in hydrochar(HC) sorption for Cu(II). The adsorption amount of the sample simulating rotten FW with Aspergillus niger (FW-160A) was 24.82 mg/g. Through the HTC process, the rotten FW can be made into heavy metal absorbents which can be stored for long term, and finally realize the reduction of volume and cost of storage. [ABSTRACT FROM AUTHOR]