Process-based numerical models developed to perform hydraulic/hydrologic/water quality analysis of watersheds and rivers have become highly sophisticated, with a corresponding increase in their computation time. However, for incidents such as water pollution, rapid analysis and decision-making are critical. This paper proposes an optimized parallelization scheme to reduce the computation time of the Environmental Fluid Dynamics Code-National Institute of Environmental Research (EFDC-NIER) model, which has been continuously developed for water pollution or algal bloom prediction in rivers. An existing source code and a parallel computational code with open multi-processing (OpenMP) and a message passing interface (MPI) were optimized, and their computation times compared. Subsequently, the simulation results for the existing EFDC model and the model with the parallel computation code were compared. Furthermore, the optimal parallel combination for hybrid parallel computation was evaluat... [more]

The friction rotary welding (FRW) of magnesium alloy to aluminum alloy was presented in a paper due to significant interest in the manufacturing industry. A genetic algorithm (GA) method for optimizing FRW process parameters of dissimilar light alloys was presented. After obtaining the welding parameters by GA method, it was possible to determine the best tensile strength of the friction joint. The obtained joints were subjected to tensile strength. The highest tensile strength TS = 178 MPa was found using a genetic algorithm for the following friction welding parameters: friction force FF = 16 kN, friction time FT = 4 s, and upsetting force UF = 44 kN. The optimized values were compared with the experimental results. The application of the genetic algorithm method allowed increasing the tensile strength joint from 88 to 180 MPa. The maximum tensile strength of the friction welded magnesium alloy-aluminum alloy joints was 73% of the base AZ31B metal. The relationship between welding pa... [more]

In this paper, subdivided kriging multi-objective optimization (SKMOO) is proposed for the optimal design of interior permanent magnet synchronous motor (IPMSM). The SKMOO with surrogate kriging model can obtain a uniform and accurate pareto front set with a reduced computation cost compared to conventional algorithms which directly adds the solution in the objective function area. In other words, the proposed algorithm uses a kriging surrogate model, so it is possible to know which design variables have the value of the objective function on the blank space. Therefore, the solution can be added directly in the objective function area. In the SKMOO algorithm, a non-dominated sorting method is used to find the pareto front set and the fill blank method is applied to prevent premature convergence. In addition, the subdivided kriging grid is proposed to make a well-distributed and more precise pareto front set. Superior performance of the SKMOO is confirmed by compared conventional multi... [more]

This paper presents the application of Taguchi design of experiment and Autodesk Moldflow® simulation in finding the optimal processing parameters for the manufacturing of natural fiber−polymer composite products. The material used in the study is a composite of recycled thermoplastic reinforced with 10% wood fibers. For the study, four critical processing parameters, namely compression time, mold temperature, melt temperate, and pressure, were selected for optimization. Process analysis was carried out in Moldflow® utilizing a combination of process parameters based on an L9 orthogonal array. Later, the warpage output from Moldflow® simulation was converted into a signal-to-noise (S/N) ratio response, and the optimum values of each processing parameter were obtained using the smaller-the-better quality characteristic. The results show that the optimum values were 60 °C, 40 s, 210 °C, and 600 kN for the mold temperature, compression time, melt temperature, and pressure, respectively. A... [more]

The optimal solution of the chemical dynamic optimization problem is the basis of automatic control operation in the chemical process, which can reduce energy consumption, increase production efficiency, and maximize economic benefit. In this paper, a modified sailfish optimizer (MSFO) combined with an equal division method is proposed for solving chemical dynamic optimization problems. Based on the basic sailfish optimizer, firstly, the tent chaotic mapping strategy is introduced to disturb the initialization of sailfish and sardine populations to avoid the loss of population diversity. Secondly, an adaptive linear reduction strategy of attack parameters is proposed to enhance the exploration and exploitation ability of sailfish. Thirdly, the updating formula of sardine position is modified, and the global optimal solution is used to attract all sardine positions, which can avoid the premature phenomenon of the algorithm. Eventually, the MSFO is applied to solve six classical optimiza... [more]

In this study, we present a new algorithm for finding the optimal friction stir welding parameters to maximize the tensile strength of a butt joint made of the semisolid material (SSM) ADC 12 aluminum. The welding parameters were rotational speed, welding speed, tool tilt, tool pin profile, and rotational direction. The method presented is a variable neighborhood strategy adaptive search (VaNSAS) approach. The process of finding the optimal friction stir welding parameters comprises five steps: (1) identifying the type and range of friction stir parameters using a literature survey; (2) performing experiments according to (1); (3) constructing a regression model using the response surface method optimizer (RSM optimizer); (4) using VaNSAS to find the optimal parameters for the model obtained from (3); and (5) confirming the results from (4) using the parameter levels obtained from (4) to perform real experiments. The computational results revealed that the tensile strength generated fr... [more]

This paper is concerned with the real-time optimization (RTO) of chemical plants, i.e., the optimization of the steady-state operating points during operation, based on inaccurate models. Specifically, modifier adaptation is employed to cope with the plant-model mismatch, which corrects the plant model and the constraint functions by bias and gradient correction terms that are computed from measured variables at the steady-states of the plant. This implies that the sampling time of the iterative RTO scheme is lower-bounded by the time to reach a new steady-state after the previously computed inputs were applied. If analytical process measurements (PAT technology) are used to obtain the steady-state responses, time delays occur due to the measurement delay of the PAT device and due to the transportation delay if the samples are transported to the instrument via pipes. This situation is quite common because the PAT devices can often only be installed at a certain distance from the measur... [more]

The advancements in human lifestyle result in growth in daily demands of products, and accordingly, an increased rate of manufacturing. However, the resources on the planet Earth are limited, thus depleting day-by-day. More goods also contribute to more end-of-life (EOL) dumping or even before EOL in some cases. Therefore, an interest in remanufacturing has appeared, and it offers a solution that can solve or perhaps mitigate the risks of consuming more resources and increasing waste. Remanufacturing is a procedure of bringing used products to “like-new” functional status with a matching warranty. However, due to its relative novelty in terms of research field and industry, remanufacturing is poorly understood. People often mix it with other terms such as recycling, reconditioning, or repair. Therefore, in this research, the focus is on the remanufacturing systems’ definition, relevance, main phases, case studies, and solution methods proposed by various researchers. The word ‘remanufa... [more]

Dynamic flux balance models (DFBM) are used in this study to infer metabolite concentrations that are difficult to measure online. The concentrations are estimated based on few available measurements. To account for uncertainty in initial conditions the DFBM is converted into a variable structure system based on a multiparametric linear programming (mpLP) where different regions of the state space are described by correspondingly different state space models. Using this variable structure system, a special set membership-based estimation approach is proposed to estimate unmeasured concentrations from few available measurements. For unobservable concentrations, upper and lower bounds are estimated. The proposed set membership estimation was applied to batch fermentation of E. coli based on DFBM.

As the carbon emissions of commercial buildings are attracting considerable attention, the integrated energy system (IES) has become a promising low-carbon method in response. In this paper, an optimization framework for low-carbon oriented integrated energy system management under electric vehicles (EV) demand response is proposed. After analyzing the charging behavior, EV charging demand is simulated. Then, the low-carbon integrated energy system model is proposed with the optimization framework considering carbon reduction. Subsequently the objective function containing carbon emission is obtained for the whole operation optimization. The results of the studied case show that the optimization framework proposed can reduce the carbon emission greatly as well as moderate economic cost, which declined because of the revenue from charging demand response. In general, the optimization of low-carbon oriented IES in commercial buildings is feasible.

Many ports worldwide continue to expand their capacity by developing a multiterminal system to catch up with the global containerized trade demand. However, this expansion strategy increases the demand for container exchange between terminals and their logistics facilities within a port, known as interterminal transport (ITT). ITT forms a complex transportation network in a large port, which must be managed efficiently given the economic and environmental implications. The use of trucks in ITT operations leads to the interterminal truck routing problem (ITTRP), which has been attracting increasing attention from researchers. One of the objectives of truck routing optimization in ITT is the minimization of empty-truck trips. Selection of the transport order (TO) based on the current truck location is critical in minimizing empty-truck trips. However, ITT entails not only transporting containers between terminals operated 24 h: in cases where containers need to be transported to a logist... [more]

Deep eutectic solvents (DESs) have properties that make them suitable candidates to be used as entrainers for extractive distillation. In the previous work, it was proven that DES(1:2) (tetrabutylammonium bromide: levulinic acid, 1:2, molar ratio) can break the cyclohexane-benzene azeotrope. In the present work, the HBA and HBD ratio and molar concentration of DES were optimized to obtain a better constitute and condition of DES to be utilized in cyclohexane and benzene extractive distillation. The physical properties and structure of the prepared DESs were characterized. Vapor−liquid equilibrium data of the ternary system (benzene + cyclohexane + DESs) were also measured at atmospheric pressure. All experimental equilibrium data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models, from which the coefficient of determination (R2) of the three pseudo-ternary systems fitting was calculated. From the obtained results,... [more]

The aim of this study was the development and optimization of chitosan and hydroxypropyl methylcellulose (HPMC) in situ gelling systems, loaded with bupivacaine hydrochloride for topical ocular administration. This study is based on the properties of two polymers: chitosan, which has mucoadhesive action and is a pH-sensitive polymer, but also the cellulose derivative hydroxypropyl methylcellulose, a thermosensitive polymer which has mucoadhesive properties and increases the viscosity of systems. The analysis and optimization of in situ gelling systems were performed based on an experimental design and response surface methodology. The following formulation parameters were considered: X1 = chitosan concentration (0.5%, 1%), X2 = HPMC E 5 LV concentration (2%, 5%) and X3 = Chitosan/HPMC E 5 LV ratio (1/1, 2/1). In addition, the parameters to be optimized were represented by the contact angle (CA (°)), viscosity and cumulative percentage of bupivacaine hydrochloride released in vitro. The... [more]

L-citrulline plays important roles in many physiological processes, and its application range is expanding rapidly. Corynebacterium glutamicum strains have the potential to be efficient L-citrulline producers. In this study, we performed optimization of L-citrulline biosynthesis operon in C. glutamicum ATCC13032 for L-citrulline production. Chromosomal integration of the integral argBEc gene from Escherichia coli (encoding natively insensitive N-acetylglutamate kinase), the deletion of the argR gene (encoding repressor ArgR), and the deletion of the argG gene (encoding argininosuccinate synthase) were achieved simultaneously by one-step genome modification and by obtaining the L-citrulline-producing strain. Then, plasmid-based overexpression of the optimized L-citrulline operon was carried out and the L-citrulline production was further improved. In fed-batch fermentation, the L-citrulline production and yield from glucose of the final strain reached 26.7 g/L and 0.18 g/g, respectively... [more]

Most spoilers are made from a sandwich structure with a honeycomb component as its core. However, the honeycomb core is sensitive to water ingress, causing damage to the control surface due to its weak moisture-resistance behavior. This study aimed to conduct the design and analysis of an improved composite structure for a coreless spoiler. A spoiler design of an aircraft, the A320, was used for the case study. The weaknesses of a coreless spoiler were identified through finite element analysis via Abaqus software. Multi-spar and multi-rib designs were studied and compared for topological optimization. The variables used for evaluation were the Tsai−Hill failure index and the critical buckling load. The design with the most potential was considered for parametric optimization to obtain the most satisfactory configuration. The results showed that the upper skin of the spoiler without a honeycomb core failed the Tsai−Hill criteria. Furthermore, the results show that the multi-spar config... [more]

(L.) Harms is commonly used for medicinal purposes in Vietnam. In traditional medicine, the plant is used to cure ischemia, reduce inflammation, and increase cerebral blood circulation. Triterpene saponins are the major chemical constituents found in the roots of P. fruticosa. This compound exhibited a broad spectrum of biological effects, including lowering blood sugar, suppressing tumor growth and inflammation. This study focused on optimizing the process of total saponins extraction from P. fruticosa roots using the ultrasonic-assisted extraction (UAE) method, ethanol solvent and response surface methodology, and Box−Behnken design model, then evaluating the cytotoxic effect against some cancer cell lines. The results showed that under the optimal conditions, including an extraction temperature of 60 °C and ultrasonic power of 185 W in 65 min, the maximum extraction yield and total saponin content were 14.51 ± 1.15% and 41.24 ± 1.68 mg/g, respectively. Moreover, the saponin extract... [more]

This study investigated the sealing performance of the multistage liquid-sealing impellers of a turbopump. To achieve this purpose, the influence of each structural parameter in the impeller on the pressurization coefficient φ2 and the leakage flow rate Q was analyzed based on response surface methodology, taking the maximum pressurization coefficient φ2 and the minimum leakage flow rate Q as the optimization objectives. We obtained satisfactory ranges for parameters φ2 and Q. A set of parameter combinations was selected as the optimization scheme using the Box−Behnken method for the optimal solution design. The numerical simulation results show that to keep φ2 and Q in the better range, the value ranges of groove width b, groove depth h and groove number z should be (12.8−14 mm), (4.5−5.6 mm) and (23.5−28), respectively. Compared with the original model, the optimized version has an average increase of about 2.5% in pressurization coefficient φ2 at each rotation speed, an average of a... [more]

The COVID-19 pandemic broke out and the global logistics industry suffered severe losses; therefore, the Fuzzy FMEA-AHP (Fuzzy Failure Mode and Effects Analysis-Analytic Hierarchy Process) method is proposed to analyze the failure reasons of the logistics system in the COVID-19 pandemic. In this article, we have made an optimization on the basis of the FMEA method: the fuzzy is integrated into the FMEA algorithm, referred to as F-RPWN (fuzzy risk priority-weighted number). Meanwhile, the AHP is used to determine the weights of risk indicators. In this article, we consider new logistics failures, such as the failure modes and failure reasons of the logistics system under the COVID-19 pandemic. There are 12 failures that have been determined, and relevant preventive and corrective measures have been recommended to cut off the path of failure propagation and reduce the impact of failures. In addition, the proposed method can help logistics firms, their supply chain partners, and customers... [more]

A nonlinear mathematical model for the optimal operation of a parallel pumping station group was established with the objective of minimizing the operation costs of the station group considering the target quantity of water extraction and flow unevenness between units of each station as constraints. The original model is decomposed into several sub-models with a single station multi-objective optimization operation with the target water lifting capacity of a single pump station as the coordinating variable. This constructed model was solved using a large-scale system decomposition dynamic programming aggregation method based on sub-system multi-objective genetic algorithm optimization. Taking the Jiangdu parallel pumping station group in the Chinese East Route of the South-to-North Water Diversion Project as a case study, the results show that under the condition of 80% water lifting load of parallel stations and 7.8 m daily average lift, the unit water lifting cost of the optimal oper... [more]

Spent coffee grounds (SCGs) generated in coffee processing for beverages and other products are a very significant organic residue that needs to be properly treated. Waste valorization via oil extraction has the potential to obtain compounds that can be used for producing biodiesel or other high-value products, such as polymers. This work focuses on the ultrasound-assisted extraction of SCG oil using n-hexane as a solvent. Three key process parameters are analyzed: temperature, extraction time, and liquid/solid (L/S) rate of solvent, using a central composite rotatable design (CCRD), an analysis that, to the author’s knowledge, is not yet available in the literature. The data were analyzed using the software StatSoft STATISTICA 13.1 (TIBCO Software Inc., Palo Alto, CA, USA). Results show that all parameters have a statistical influence on the process performance (p < 0.05), being the L/S ratio the most significant, followed by extraction time and temperature. An analysis of variance... [more]

Low-temperature atmospheric pressure (AP) plasma technologies have recently proven to offer a range of interesting opportunities for the preparation of a variety of nanocomposite (NC) coatings with different chemical compositions, structures, and morphologies. Since the late 2000s, numerous strategies have been implemented for the deposition of this intriguing class of coatings by using both direct and remote AP plasma sources. Interestingly, considerable progress has been made in the development of aerosol-assisted deposition processes in which the use of either precursor solutions or nanoparticle dispersions in aerosol form allows greatly widening the range of constituents that can be combined in the plasma-deposited NC films. This review summarizes the research published on this topic so far and, specifically, aims to present a concise survey of the developed plasma processes, with particular focus on their optimization as well as on the structural and functional properties of the N... [more]

exerts various medicinal effects and has been used as a traditional medicine for inflammation, asthma, gastritis, and liver disease. Recently, we reported the xanthine oxidase inhibitory activity of C. lanceolata extract and that lobetyolin, one of the key components, was a xanthine oxidase inhibitor. Lobetyolin showed anti-hyperuricemic activity in vitro and in vivo. In this study, we prepared various types of C. lanceolata extracts for the development of functional materials and natural drugs. We present the optimal analytical approach for the quality control and extraction optimization of C. lanceolata preparations. We established and validated a HPLC analysis for easy separation and quantification of the lobetyolin biomarker. Solvent extracts of C. lanceolata root were prepared and the profiles of the active marker and the optimal extraction methods were evaluated. The 100% ethanolic extract demonstrated the highest lobetyolin content. The validated HPLC method confirmed that lobet... [more]

Wheat straw and eucalyptus residues were pretreated in a biphasic system, constituted of butanol (n-butanol) or 2-methyltetrahydrofuran (2M-THF) and aqueous oxalic acid solutions. The pretreatments were carried out in a 300 mL Parr reactor (Autoclave Buchi Limbo-li®) with a solid load of 5 wt.%, the temperature in the range 140−180 °C, oxalic acid load from 0 to 10 wt.% and a duration of 30−90 min. The obtained slurry was then fractionated in three streams: the aqueous phase which contained solubilized hemicellulose, the organic phase which contained the solvated lignin, and the solid residue which contained cellulose. The solid was hydrolyzed using a commercial mix of enzymes to assess cellulose digestibility and glucose production. The pretreatment was optimized to maximize the purity of the cellulose and hemicellulose fractions and the glucose recovery as free sugar. The optimization was done by using an experimental design and response surface methodology. The mass flow details of... [more]

Design optimization on the Indonesia N219 seaplane catamaran is necessary to provide better service to rural islands of Indonesia. This research aims at decreasing drag using a design based on biomimicry by imitating the hydrodynamic characteristics of sailfish (Istiophorus platypterus) for pontoon floats. The design is then validated using a numerical fluid test using ANSYS Fluent to see the reduction in drag due to the change from a conventional or Wipeline® 13000 design to a biomimetics adaptation design. Next, further optimization was carried out based on the adaptation design based on trim tests, clearance tests, and deadrise angle dimensions suitable for biomimicry designs at Froude number speeds of 0.4 to 0.7. The design results with the adaptation of biomimicry show that a change in the design with this optimization affects a drag reduction that reaches 30% of the total drag generated by the conventional design.

This paper proposes a robust optimization algorithm customized for the optimal design of electric machines. The proposed algorithm, termed “robust explorative particle swarm optimization” (RePSO), is a hybrid algorithm that affords high accuracy and a high search speed when determining robust optimal solutions. To ensure the robustness of the determined optimal solution, RePSO employs the rate of change of the cost function. When this rate is high, the cost function appears as a steep curve, indicating low robustness; in contrast, when the rate is low, the cost function takes the form of a gradual curve, indicating high robustness. For verification, the performance of the proposed algorithm was compared with those of the conventional methods of robust particle swarm optimization and explorative particle swarm optimization with a Gaussian basis test function. The target performance of the traction motor for the optimal design was derived using a simulation of vehicle driving performance... [more]