Although constructing a dam can bring significant economic and social benefits to a region, it can be catastrophic for the population living downstream when it breaks. Given the dynamic and nonlinear characteristics of dam deformation, the traditional dam prediction model has been unable to meet the actual engineering demands. Consequently, this paper advocates for a novel method to solve this issue. The proposed method is based on the optimization of improved chicken swarm (ICSO) and support vector machine (SVM). To begin with, the mean square error is used as the objective function, and then, we apply the improved chicken swarm algorithm to iterate continuously, and finally, the optimal SVM parameters are obtained. Through the modeling and simulation experiments of a nonlinear system, the validity of the improved chicken swarm algorithm to optimize an SVM model has been verified. Based on the horizontal displacement monitoring data of FengMan Dam, this paper analyzed the influencing... [more]

The hydrodynamic characteristics of a rod-shaped squirmer swimming near a wall were studied numerically using the immersed boundary-lattice Boltzmann method in the swimming Reynolds number range of 0.1 ≤ Res ≤ 2.0, where the number of assembled squirmers was 2 ≤ i ≤ 4 and the distance between two adjacent assembled squirmers was 0.75 d ≤ s ≤ 1.5 d (d is the diameter of a single squirmer). The effect of Res, i and s on the swimming mode of the squirmer was explored. The results showed that there are four swimming modes after the first collision between the rod-shaped squirmer and the wall. There are also four swimming modes when Res changes from 0.1 to 2.0. Puller, pusher and neutral squirmers showed different swimming modes when i changed, and the effect degree of the flow at the previous moment on the squirmer’s motion was different for different values of i. The change in s only affected the trajectory of the squirmer without changing its motion mode. Puller, pusher and neutral squir... [more]

The paper studies a new distributed control method to solve the economic dispatch problem (EDP) under directed topology based on consensus protocol. Electrical equipment is closely related to frequency, and the frequency of each generator varies independently during operation. Therefore, it hinders the realization of economic dispatch. To solve the problem, we combine a frequency regulator with a consensus protocol, which eliminates the effect of frequency variation on the designed consensus algorithm. Meanwhile, considering the problem of excessive communication cost and low computational efficiency in large-scale power systems, an event-triggered mechanism is introduced into the designed algorithm. Furthermore, in order to overcome the unexpected loss of communication links, the time-varying topology mechanism is employed to develop the distributed economic dispatch (DED) algorithm to improve the robustness. Then, the stability of the above algorithm is proved by graph theory and con... [more]

Carbon Capture and Storage (CCS) technology has attracted increasing attention as global climate change accelerates. Carbon dioxide removal processes under development include pressure swing adsorption (PSA) and chemical absorption using amine solvents. In this paper, an ammonia solvent, which is relatively inexpensive and has good material properties, was used instead of amines in the carbon dioxide removal process simulation as a chemical absorption method. This simulation used the eNRTL thermodynamics model which has the advantage of predicting ions in the liquid phase in Aspen Plus. A case study (Case Study 1) was conducted to verify the validity of the thermodynamic model. The purpose of this research was to find the operating conditions to eliminate more than 90% of the carbon dioxide contained in the flue gas from coal-fired power stations, and to lower heat duty and operating cost conditions. A second case study (Case Study 2) was conducted to find the operating conditions by c... [more]

Unmanned aerial vehicle edge networks (UENs) can reduce the cache load of the core network and improve system performance to provide users with efficient content services. However, the time-varying characteristics of content popularity in UENs lead to a low accuracy of popularity prediction, and the capacity limitations of wireless channel conditions lead to a lower cache hit rate than the rates of traditional fiber-optic-based cache strategies. Therefore, this paper proposes the discrete artificial bee colony cache strategy of UENs (DABCCSU). First, the information−dynamics−dissemination model of UENs (IDDMU) is established to deduce the coupling relationship between the channel capacity and the service probability in IDDMU. The influence of the service probability change on the content dissemination process is discussed, and the content popularity in UENs is predicted by the state iteration matrix. Then, the discrete artificial bee colony cache (DABCC) optimization algorithm is propo... [more]

In this paper, a manufacturing process for a single-server permutation Flow Shop Scheduling Problem with sequence dependant, disjoint setups and makespan minimization is considered. The full problem is divided into two levels, and the lower level, aimed at finding an optimal order of setups for a given fixed order of jobs, is tackled. The mathematical model of the problem is presented along with a solution representation. Several problem properties pertaining to the problem solution space are formulated. The connection between the number of feasible solutions and the Catalan numbers is demonstrated and a Dynamic Programming-based algorithm for counting feasible solution is proposed. An elimination property is proved, which allows one to disregard up 99.99% of the solution space for instances with 10 jobs and 4 machines. A refinement procedure allowing us to improve the solution in the time required to evaluate it is shown. To illustrate how the properties can be used, two solving metho... [more]

This article aims to review, analyze, and classify the published research applications of the Data Envelopment Analysis (DEA) window analysis technique. The number of filtered articles included in the study is 109, retrieved from 79 journals in the web of science (WoS) database during the period 1996−2019. The papers are classified into 15 application areas: energy and environment, transportation, banking, tourism, manufacturing, healthcare, power, agriculture, education, finance, petroleum, sport, communication, water, and miscellaneous. Moreover, we present descriptive statistics related to the growth of publications over time, the journals publishing the articles, keyword terms used, length of articles, and authorship analysis (including institutional and country affiliations). To the best of the authors knowledge, this is the first survey reviewing the literature of the DEA window analysis applications in the 15 areas mentioned in the paper.

In view of the problems associated with the poor stability of coal walls, coal slide and leakage of top-coal at the tunnel excavation working face under a soft and extra-thick coal roof, the surrounding rock at the tunnel excavation working face must be strengthened. The theoretical analysis of rock pressure, numerical simulation and other methods were comprehensively used to study the coal-wall-slicing mechanism. Given the characteristics of a soft and extra-thick coal roof, the combined supporting technology of “coal wall water injection + metal roof frame” is proposed. The findings show that in the process of roadway excavation, the coal−rock junctions of the wall and the middle part of the roof are weak areas that are prone to spalling and therefore need to be strengthened. Laboratory tests determined the moisture content of the coal body during tunneling to provide data for the parameter design of coal wall water injection. Safe and efficient excavation of the roadway was ensured... [more]

The marine ecosystem is one of the richest sources of biologically active compounds, such as enzymes, among which seaweed is one of the most diverse marine species and has a rich diversity of bacteria that produce different enzymes. Among these, the bacteria-derived xylanase enzyme has many applications in the fruit juice, paper, and baking industries; so, to consider the economic value of the xylanase enzyme and the isolation and identification of xylanase-producing bacteria is of particular importance. In this study, specimens of the alga Ulva flexuosa species were collected from the coasts of Bandar Abbas and Qeshm Island. The bacteria coexisting with the algae were isolated using a nutrient agar medium. The bacteria producing the xylanase enzyme were then screened by a specific solid culture medium containing xylan, and the activity of the xylanase enzyme isolated from the bacteria was measured using a xylan substrate. The bacteria with the highest enzymatic activity were selected... [more]

Water pollution is a severe health concern. Several studies have recently demonstrated the efficacy of various approaches for treating wastewater from anthropogenic activities. Wastewater treatment is an artificial procedure that removes contaminants and impurities from wastewater or sewage before discharging the effluent back into the environment. It can also be recycled by being further treated or polished to provide safe quality water for use, such as potable water. Municipal and industrial wastewater treatment systems are designed to create effluent discharged to the surrounding environments and must comply with various authorities’ environmental discharge quality rules. An effective, low-cost, environmentally friendly, and long-term wastewater treatment system is critical to protecting our unique and finite water supplies. Moreover, this paper discusses water pollution classification and the three traditional treatment methods of precipitation/encapsulation, adsorption, and membra... [more]

Under the dual−carbon goal, the research on energy conservation and emission reduction of new energy vehicles has once again become a current hotspot, and plug−in hybrid electric vehicles (PHEVs) are the first to bear the brunt. In order to improve the fuel economy of PHEV, an adaptive energy management strategy is designed on the basis of the intelligent prediction of driving cycles. Firstly, according to the vehicle dynamics model, the optimal control objective function of PHEV is established, and the relationship between vehicle fuel consumption and driving cycle is analyzed. Secondly, the initial weights and threshold of the backpropagation (BP) neural network are optimized using the particle swarm optimization (PSO) algorithm, and a PSO−BP neural network vehicle velocity prediction controller is established. Thirdly, combined with the approximate equivalent consumption minimization strategy (ECMS) algorithm to calculate the optimal initial equivalent factor in the prediction time... [more]

The development of drug resistance to presently available synthetic medicines leads us to investigate naturally produced small bioactive molecules to treat drug-resistant diseases, such as cancer and other diseases [...]

This work demonstrates the potential utility of ferrate(VI)-based advanced oxidation processes for the degradation of a representative UV filter, BP-4. The operational parameters of oxidant dose and temperature were determined with kinetic experiments. In addition, the effects of water constituents including anions (Cl−, HCO3−, NO3−, SO42−), cations (Na+, K+, Ca2+, Mg2+, Cu2+, Fe3+), and humic acid (HA) were investigated. Results suggested that the removal rate of BP-4 (5 mg/L) could reach 95% in 60 min, when [Fe(VI)]:[BP-4] = 100:1, T = 25 °C and pH = 7.0, The presence of K+, Cu2+ and Fe3+ could promote the removal of BP-4, but Cl−, SO42−, NO3−, HA and Na+ could significantly inhibit the removal of BP-4. Furthermore, this Fe(VI) oxidation processes has good feasibility in real water samples. These results may provide useful information for the environmental elimination of benzophenone-type UV filters by Fe(VI).

The successive growth of the population, degradation of the natural environment, and development of civilization diseases force a continuous increase in the production of high-quality food [...]

Thallium (I) was removed from aqueous solution by using gamma-alumina nanoparticles (γANPs) materials as nano adsorbents. Varied experimental conditions such as adsorbent dose, agitation time, initial concentration, pH, and temperature effects were carried out in batch conditions in view of the optimization of thallium (I) adsorption and the identification of the adsorption mechanisms in the system γANPs-Tl. The pH effect indicated a remarkable increase in the quantity of Tl(I) removed for pH values ranging from 4 to 8, an almost constant magnitude for pH values between 8 and 10, and a decrease for pH values above 10. Considering an initial Tl(I) concentration of 20 µg/L and an adsorbent dose of 1 g/L at a pH value of 8.5, the removal was achieved at 95.12 ± 0.02% efficiency. The pseudo-second-order kinetics and the Freundlich isotherm perfectly described the adsorption mechanism. The process of thallium (I) adsorption reaction, as highlighted by thermodynamic investigations, was found... [more]

The Aircraft Arrival/Departure Problem (AADSP) is the core problem in current runway system, even has become the bottleneck to prevent the improvement of the airport efficiency. This paper studies the single runway AADSP. A Mixed Integer Programming (MIP) model is constructed and an algorithm named Ant Colony based on Rank 2 Matrix Approximation (RMA-AC) method is proposed. Numerical results validate that the new algorithm, as well as the new model, exhibits better performance than CPLEX and the traditional two-phase algorithm. The runway efficiency enhanced by RMA-AC, within 20 s computation, is about 2−5% even for the 800 aircraft sequences. It is a promising method to improve the efficiency of the future aircraft scheduling system.

The construction machinery and vehicles, especially the explosion-proof and explosion-isolation ability of the vehicles are playing an increasingly important role in the complex and unpredictable emergency rescue field. In this paper, the explosion-proof housing of hydraulic system power unit applied in engineering machinery is investigated, wherein the power unit includes motor, power supply and control element. Motor-driven hydraulic pump provides the necessary power for the hydraulic system. The gas explosion process, basic parameters, flame acceleration mechanism and the theory model of gas explosion in finite space are analyzed. Relevant mathematical models of the experimental gas explosion for explosion-proof cavity are established. Furthermore, the models are analyzed by numerical method. We simulate the dynamic process of explosion by software. The analysis, examination and simulation of structural strength are conducted on the explosion-proof cavity according to the maximum ex... [more]

The propellant gas flow of a supersonic rocket in inappropriate operating conditions can cause excessive ablation inside a nozzle. In this research, conjugate heat transfer analysis (CHTA), consisting of computational fluid dynamics (CFD) and finite element analysis (FEA), was applied to investigate the gas flow and ablation of a 122 mm nozzle as a case study in the transient state, based on actual operating conditions. First, the nozzle was tested in a static experiment. Then, the experimental results were employed for CHTA settings and validation. Next, after completing the CFD calculation, the results revealed that the nozzle’s gas flow, temperature, pressure, Mach number, shock, etc. were consistent with theoretical results. Finally, using the CFD results as loads, the FEA results showed the equivalent von Mises stress (σv), which was consistent with the ablation results from the experiment, as expected. The more the σv, the greater the ablation. Both σv and ablation were high near... [more]

Residue catalytic hydrogenation was carried out in a two-stage downflow fixed-bed reactor system, with a HDM catalyst in the first stage and HDS catalyst in the second one, to mimic the industrial operation. The experiments were run at five sets of temperatures (395 °C (first reactor)/405 °C (second reactor), 400 °C/410 °C, 405 °C/415 °C, 410 °C/420 °C, and 420 °C/430 °C). It was found that the initial stage deactivation was mainly caused by the rapid deposition of coke. Gradually, the deposition of metal sulfides leads to a slow deactivation in the middle stage of operation. A deactivation model that considers the catalyst activity as a function of TOS was proposed and applied to the hydrotreating reaction. The deactivation parameters of HDCCR, HDS, HDNi, and HDV in the two reactors were obtained by fitting the experimental data at the outlet of the two reactors. According to the deactivation curves of catalysts, it is proposed that the deactivation of HDM catalyst is faster than that... [more]

In this paper, a technique that integrates methods of dynamic economic optimization and real-time control by including economic model predictive control and closed-loop predictive control has been developed, using a two-layer structure. The upper layer, which consists of an economic nonlinear MPC (NMPC), makes use of the updated state information to optimize some economic cost indices and calculates in real time the economically optimal trajectories for the process states. The lower layer uses a closed-loop nonlinear GPC (NCLGPC) to calculate the control actions that allow for the outputs of the process to follow the trajectories received from the upper layer. This paper also includes the theoretical demonstration proving that the deviation between the state of the closed-loop system and the economically time varying trajectory provided by the upper layer is bounded, thus guaranteeing stability. The proposed approach is based on the use of nonlinear models to describe all the relevant... [more]

Modeling is the primary point to conveying product characteristics. Accurately capturing the image needs of users for modeling is an important way to effectively improve product design efficiency. Quantitative theory type I is a method to solve the internal law between the user’s target image and the product modeling characteristics by building a mathematical model. Aiming at the problems of abundant product modeling design elements, diversified combination methods, and high design cost due to the subjective ambiguity of user images, a topological design method of product modeling based on quantification theory I is proposed. This method uses the semantic difference method and statistical method to obtain the quantitative data of perceptual semantic features of product modeling to represent the explicit and implicit needs of users. Based on the topological transformation, the topological analysis and modeling of the two types of requirements are carried out. The mapping model of produc... [more]

Volcanic activity is characteristic of seismic zones. Consequently, volcanic material form part of the landscape in places where earthquakes are common natural phenomena. As volcanic wastes (VW) show pozzolanic activity, the substitution of manufactured Portland cement (PC) with VW is clearly a desirable option not only from an economical point of view but also to reduce the CO2 fingerprint. Therefore, designing concretes with volcanic Portland cements (VPC) clearly contributes to cleaner cement production. Construction and building activities in seismic zones need to use a specific kind of concrete—self-compacting concrete (SCC). The challenge we focused on was the design of SCC using VPC. The flow behavior of SCC is characterized by low yield stress, high plastic viscosity, and shear-thickening behavior at high shear. However, obtaining these striking properties of the concrete is not easy with traditional concrete flow tests (Abrams cone, etc.). Moreover, these methods are very cost... [more]

Nowadays, energy saving, and green sustainability are influencing the development of all industries, including the construction industry. In recent years, geopolymeric cement and concrete have become hot topic materials as a replacement for traditional OPC; this work carried out orthogonal experiments to identify four potential factors affecting the basic properties of the metakaolin-geopolymeric cement specimens. The results showed that the metakaolin and activator contents were the two primary influencing factors. Given the importance of studying the durability of building restoration materials in harsh environments, this experiment focused on testing the bond strength, permeability resistance, sulphate corrosion resistance, and freeze-thaw resistance of metakaolin geopolymer pastes with different proportions of metakaolin dopant and alkali activator content. The findings are that durability of the formed specimens significantly improved when suitable metakaolin and activator content... [more]

Aiming at the problem of the difficult separation of film in the process of farmland residual film recovery, a clamping conveying residual film recovery device was designed and studied. The device was mainly composed of a clamp plate, clamp plate conveying chain, chain wheel drive shaft, and the residual film conveying chain and frame. Firstly, the structure and working principle of the device are introduced. The tensile properties of the residual film are investigated to determine the relationship between the average clamping force, the height of the clamp plate, the spacing of the clamp plate, and the rotational speed of the sprocket. Then, the mechanical properties of the residual film are discussed. The influence weight of each factor on the film impurity separation rate is summarized by single factor tests. The regression equation between the factors and film impurity separation rate is established. The results of the variance analysis of regression equation show that the film imp... [more]

This paper investigates bending and compressive strengths as mechanical characteristics of cement-based repair mortar containing nano-silica (NS) and micro-silica (SF) as cement replacements particles and polyvinyl alcohol (PVA) fibers. The mentioned materials were added to the mortar in three different conditions, including single (just one material), binary (mixture of two admixtures), and ternary (mixture of all three admixtures) modes. The use of PVA fibers, nano-silica and micro-silica in the triple combination of a cement-based mortar is the primary objective of the current research. In total, 28 mix designs with various percentages of particles and fiber were employed in the current study, and 112 different specimens were prepared to conduct the experimental research. The compressive and flexural strength results have been selected as the criteria for obtaining the optimum mix design for each condition. In order to specify the mechanical characteristics of specimens, a compressi... [more]