The electrohydraulic servo variable speed volume pump control system (hereinafter referred to as ESPCS) is integrated with a permanent magnet synchronous motor (hereinafter referred to as servo motor), a fixed-displacement pump, and a hydraulic cylinder. By controlling the servo motor speed, the output flow of the system can be controlled, as can the displacement, force, and speed of the hydraulic cylinder. Compared with the traditional electro-hydraulic servo valve control system, the ESPCS has the advantages of high power-to-weight ratio, energy saving, and environmental friendliness. However, due to the extremely nonlinear flow output of the ESPCS, further improvement of system control performance is greatly hindered. This paper focuses on the nonlinear characteristics of servo motor, fixed-displacement pump, hydraulic cylinder, and other key components in the system. A compensation method based on nonlinear characteristic mapping is proposed. Compared with the traditional PID contr... [more]

A mathematical modeling approach was used to test different design modifications in a flash smelting settler to reduce the copper losses in slag, which is economically disadvantageous for copper processing using the pyrometallurgical route. The main purpose of this study was to find ways to reduce copper losses in slag by improving the settling and coalescence of copper matte droplets, in particular, the smallest droplet sizes of ≤100 µm. These improvements inside the flash smelting (FS) settler were targeted through different settler design modifications. Three different design schemes were tested using the commercial computational fluid dynamics (CFD) software, Ansys Fluent. These settler design modification schemes included the impact of various baffle types, positioning, the height inside the settler, and settler bottom inclinations. Simulations were carried out with and without coalescence and the results were compared with normal settler design. The results revealed that the sett... [more]

An annular jet pump (AJP) and a screw centrifugal pump (SCP) are special-purpose pumps used for transportation. The flow fields in the AJP and SCP are like those in a diffuser without and with an impeller, respectively. The flow from diffuser inlet to outlet takes place via the conversion of kinetic energy to static pressure. J-Groove is installed in the diffuser wall of an AJP and SCP to induce reverse flow from the diffuser outlet to the inlet, which suppresses the cavitation. CFD analysis was carried out to verify the conceptual design and understand the internal flow field of an AJP and SCP with J-Groove. The CFD analysis showed that the J-Groove installation in the AJP and SCP improved suction performance. The reverse flow in the J-Groove is due to the pressure difference between the diffuser outlet and the inlet. The numerical analysis results showed that the reverse flow mechanism is dependent on the flow conditions, cavitation number, and presence of the impeller. In a higher f... [more]

Proper inventory management is vital to achieving sustainability within a supply chain and is also related to a company’s cash flow through the funds represented by the inventory. Therefore, it is necessary to balance excess inventory and insufficient inventory. However, this can be difficult to achieve in the presence of stochastic demand because decisions must be made in an uncertain environment and the inventory policy bears risks associated with each decision. This study reports an extension of the single-period model for the inventory problem under uncertain demand. We proposed incorporating a Gaussian stochastic process into the model using the associated posterior distribution of the Gaussian process as a distribution for the demand. This enables the modeling of data from historical inventory demand using the Gaussian process theory, which adapts well to small datasets and provides measurements of the risks associated with the predictions made. Thus, unlike other works that assu... [more]

Here, FeAlOx catalytic deconstruction of polyethylene in a domestic microwave oven is reported. With the starting weight ratio of FeAlOx to polyethylene at 1:1, the concentration and yield of H2 reach up to 67.85 vol% and 48.1 mmol g−1plastic, respectively. CNTs@Fe3O4/Fe3C/Fe composite, which exhibits excellent microwave absorption properties, is generated simultaneously. The minimum reflection loss (RLmin) of the solid product reaches −54.78 dB at 15 GHz with an effective absorption bandwidth of 4.5 GHz at the thickness of 1.57 mm.

The primary goal of business organization is optimally maximizing their productivity and profit whilst reducing the cost resulting from lost sales and services given to their customers, which can be achieved by exceeding the balance between the demand and supply. Analyzing real-world situations, including integrated queuing-inventory systems, such as M/M/1-systems and M/M/1/∞-systems, can help business organizations reach this goal. This research analyzes integrated queuing-inventory systems with lost sales validated under a deterministic and uniformly distributed order size scheme under continuous review. The limited integrated inventory-queuing M/M/1/N-1-system was chosen as subject of our interest due to its closeness to reality. Thus, this system with exponentially distributed deteriorating products and random planning time with lost sales was simulated. This research aimed to analyze customers’ sanctification by studying the addition of the deterioration parameter γ to the model u... [more]

Deep eutectic solvents (DESs) have been used for the pretreatment of lignocellulose and showed selective dissolution for different lignocellulosic components. In this study, six new ternary DESs were synthesized on the basis of anhydrous oxalic acid DES by adding alcohol, acid, and deionized water, respectively, including choline chloride/anhydrous oxalic acid/ethylene glycol (ChCl-OA-EG), choline chloride/anhydrous oxalic acid/glycerol (ChCl-OA-G), choline chloride/anhydrous oxalic acid/lactic acid (ChCl-OA-LA), choline chloride/anhydrous oxalic acid/malonic acid (ChCl-OA-MA), choline chloride/anhydrous oxalic acid/10% H2O (v/v) (ChCl-OA + 10% H2O), and choline chloride/anhydrous oxalic acid/20% H2O (v/v) (ChCl-OA + 20% H2O). The lignin in bagasse was extracted and separated with these ternary DESs, and Fourier Transform Infrared (FTIR), Scanning electron microscope (SEM), X-ray diffraction (XRD), Two-dimensional Heteronuclear Single Quantum Coherence (2D HSQC), and Thermogravimetric... [more]

In recent years, sewage sludge (SS) and bio-waste management have attracted increasing environmental attention. In this study, hydrothermal carbonization (HTC) technology is investigated in the framework of a co-treatment of sewage sludge digestate (SSD) and an organic fraction of municipal solid waste (OW). The proposed configuration integrates HTC with anaerobic digestion (AD) in an inter-stage configuration (AD1 + HTC + AD2). The effects of different percentages of OW added to SSD in the HTC treatment are evaluated in terms of characteristics and methane yield of the produced HTC liquor (HTCL) and HTC slurry (i.e., the mixture hydrochar-HTCL), as well as dewaterability of the HTC slurry. Results show that, with the increase in the percentage of OW in the OW-SSD mixture fed to the HTC process, production of biogas and biomethane of both HTC slurry and HTCL increases. The highest biogas production is achieved when a mixture consisting of half SSD and half OW is used, reaching 160 ± 10... [more]

Around the globe, only 30−50% of the amount of oil estimated to be in reservoirs (“original oil in place”) can be obtained using primary and secondary oil recovery methods. Enhanced oil recovery methods are required in the oil processing industry, and the use of microbially produced amphiphilic molecules (biosurfactants) is considered a promising efficient and environmentally friendly method. In the present study, biosurfactants produced by the Pseudomonas putida PP021 isolate were extracted and characterized, and their potential to enhance oil recovery was demonstrated. It was found that the cell-free biosurfactant-containing supernatant decreased the air−water interface tension from 74 to 28 mN m−1. Using TLC and FTIR methods, the biosurfactants produced by the isolate were classified as mono- and di-rhamnolipid mixtures. In the isolates’ genome, the genes rhlB and rhlC, encoding enzymes involved in the synthesis of mono- and di-rhamnolipids, respectively, were revealed. Both genes w... [more]

The current study aims to investigate the thermal-diffusion and diffusion-thermo effects on heat and mass transfer in third-grade fluid with Darcy−Forchheimer relation impact over an exponentially inclined stretching sheet embedded in a porous medium. The proposed mechanism in terms non-linear and coupled partial differential equations is reduced to set of ordinary differential equations by employing an appropriate similarity variable formulation. The reduced form of equations is solved by using the MATLAB built-in numerical solver bvp4c. The numerical results for unknown physical properties such as velocity profile, temperature field, and mass concentration along with their gradients such as the skin friction, the rate of heat transfer, and the rate of mass transfer at angle of inclination α=π/6 are obtained under the impact of material parameters that appear in the flow model. The solutions are displayed in forms of graphs as well as tables and are discussed with physical reasoning.... [more]

The paper presents a useful engineering model for the design of preliminary hybrid rocket engines. This model involves the experimentally obtained equation regarding the speed of the burning interface between solid fuel and gaseous phase, called the regression rate. This regression rate characterizes the mass rate of the burning fuel and additionally the mass rate of the oxidizer through the imposed ratio of these mass rates during combustion. The preliminary design is applied to combustion using pure HTPB and gaseous oxygen and was developed for three cases, constant regression rate, constant oxygen mass flow rate and constant O/F (ratio of mass rates of oxygen and of fuel). The design evaluates the initial fuel port geometry, the initial mass of fuel and oxygen, the combustion time, the thrust at sea level, and the time-dependent functions of regression rate, of fuel and oxygen mass rates, and of thrust. It was assumed that the regression rate formula applies at any time of combustio... [more]

Transient stability during grid fault is experienced differently in modern power systems, especially in wind-turbine-dominated power systems. In this paper, transient behavior and stability issues of a direct drive wind turbine during fault recovery in DC-link voltage control timescale are studied. First, the motion equation model that depicts the phase and amplitude dynamics of internal voltage driven by unbalanced active and reactive power is developed to physically depict transient characteristics of the direct drive wind turbine itself. Considering transient switch control induced by active power climbing, the two-stage model is employed. Based on the motion equation model, transient behavior during fault recovery in a single machine infinite bus system is studied, and the analysis is also divided into two stages: during and after active power climbing. During active power climbing, a novel approximate analytical expression is proposed to clearly reveal the frequency dynamics of th... [more]

The intersection behavior of hydraulic fractures and single natural fractures has been studied in detail; however, in fractured reservoirs, natural fractures are numerous and interlaced and the intersection of hydraulic fractures and multiple natural fractures occurs during the fracturing process. This intersection behavior is more complex and there is a lack of research on this topic at present. In this study, a numerical simulation model of the interaction between hydraulic fractures and a series of natural fractures was established, the main factors that affect the formation scale of a fracture network during the hydraulic fracturing of a fractured reservoir were studied using the numerical simulation method, and the parameters were also studied. The results showed that the natural fracture trend, in situ stress difference, and injection flow rate have an impact on the scale of a fracture network. The larger the in situ stress difference, the smaller the scale of the fracture networ... [more]

This research topic aims at enterprise-wide modeling and optimization (EWMO) through the development and application of integrated modeling, simulation and optimization methodologies, and computer-aided tools for reliable and sustainable improvement opportunities within the entire manufacturing network (raw materials, production plants, distribution, retailers, and customers) and its components [...]

The short-circuit flow, which is discharged from the vortex finder without separation, seriously affects the processing efficiency of the hydrocyclone. In this paper, the experimental test and numerical simulation methods are used to study the effect of the vortex finder and feed parameters on the short-circuit flow and separation performance. The Reynolds Stress method (RSM), Volume of Fluid (VOF), and Mixture model were adopted to predict the separation process in the hydrocyclone. The simulation results are analyzed in terms of the short-circuit flow rate, the ratio of the short-circuit flow rate to the inlet flow rate (hereafter this paper will be abbreviated as “its ratio”) and the separation efficiency. The results indicate that the smaller vortex finder diameter, thick-walled vortex finder, and moderate vortex finder length are conducive to inhibiting the short-circuit flow and decreasing the cut size (d50). A faster inlet velocity and higher feed concentration could increase th... [more]

Person re-identification(Re-ID) technology has been a research hotspot in intelligent video surveillance, which accurately retrieves specific pedestrians from massive video data. Most research focuses on the short-term scenarios of person Re-ID to deal with general problems, such as occlusion, illumination change, and view variance. The appearance change or similar appearance problem in the long-term scenarios has has not been the focus of past research. This paper proposes a novel Re-ID framework consisting of a two-branch model to fuse the appearance and gait feature to overcome covariate changes. Firstly, we extract the appearance features from a video sequence by ResNet50 and leverage average pooling to aggregate the features. Secondly, we design an improved gait representation to obtain a person’s motion information and exclude the effects of external covariates. Specifically, we accumulate the difference between silhouettes to form an active energy image (AEI) and then mask the m... [more]

This paper focuses on the problem of event-triggered H∞ asynchronous filtering for Markov jump nonlinear systems with varying delay and unknown probabilities. An event-triggered scheduling scheme is adopted to decrease the transmission rate of measured outputs. The devised filter is mode dependent and asynchronous with the original system, which is represented by a hidden Markov model (HMM). Both the probability information involved in the original system and the filter are assumed to be only partly available. Under this framework, via employing the Lyapunov−Krasovskii functional and matrix inequality transformation techniques, a sufficient condition is given and the filter is further devised to ensure that the resulting filtering error dynamic system is stochastically stable with a desired H∞ disturbance attenuation performance. Lastly, the validity of the presented filter design scheme is verified through a numerical example.

The use of food agricultural wastes as a source of bioactive compounds is an alternative to reduce their environmental impact and generate the possibility of producing value-added products as functional foods. This study aimed to extract and microencapsulate the bioactive compounds from the red banana peel (Musa acuminata Colla AAA “Red”) by spray drying and to evaluate the bioaccessibility of the bioactive compounds by in vitro digestion. The microencapsulation of bioactive compounds was carried out using two wall materials gum arabic (GA) and soy protein isolate (SPI). Microencapsulation using GA and SPI proved to be an effective technique to protect the phenolic compounds, flavonoids and antioxidant capacity of banana peel extract under in vitro digestion conditions. The extract without the encapsulation process suffered a significant (p ≤ 0.05) decrease in bioactive compounds and antioxidant capacity after in vitro digestion. Although microcapsules with SPI held the bioactive compo... [more]

Plate heat exchangers (PHEs) have significant potential to improve energy efficiency in the process industries. However, realizing their full potential to achieve such energy savings requires a systematic approach to screen the many options available. Thus, this work presents a generalized novel approach for the optimal design of both gasket and welded plate heat exchangers, with different plate geometries and flow configurations. A new design method coupled with an optimization framework is proposed to obtain the optimal solution with minimum total transfer area by setting up a series of relations between temperatures among each single-pass block with known inlet and outlet temperatures of process streams. An MINLP mathematical model is developed to select the best combination of the flow pass configuration and available commercial plate geometries within practical design constraints. The differences between the design methodology of gasket and welded PHEs are highlighted. Two case st... [more]

A 20-ft containerized biological pilot system consisting of both an anaerobic expended granular sludge bed (EGSB) and an aerobic biofilm continuous flow intermittent clean (CFIC®) system has been designed, constructed, and delivered onsite at a pharmaceutical wastewater producer for a wastewater treatment study. The pilot was operated for a total of 317 days, including 147 days of adaptive phase and 170 days of testing phase. A pilot adaptive phase feeding wastewater COD concentration from 2 to 50 g/L with salinity up to 16 g/L was carried out, achieving EGSB where COD removal reached over 80 to 95% at OLR up to 22 kg COD/m3·d. In the testing phase, with repressive practical wastewater, the EGSB can remove over 97% of feed COD (with up to 82% acetic acid) at an average 16.3 kg COD/m3·d. The high wastewater salinity at 20 g/L did not inhibit COD removal efficiency by the system. The complete system with EGSB and aerobic stage was very stable and removed over 90−97% of the total COD depe... [more]

There is a huge carbon pool in the lakeside, which is sensitive to environmental changes and can very easily be transformed into a carbon source as land from the lake is reclaimed. In this paper, West Mauri Lake was employed as a case study to examine soil organic carbon (SOC) and its controlling factors along the lakeside. Four transects of land use (i.e., vegetation) types along the landward lakeside were identified as the fluctuation zone, the beach zone, the mesozoic farmland rewetting zone and the xerophytic farmland rewetting zone. With the increase in soil depth, SOC in the lakeside decreased significantly (p < 0.05). SOC had an obvious seasonal variation (p < 0.001), ranking in order: winter (December) > spring (February) > summer (May). Among the aforementioned transects, SOC density differed significantly (p < 0.05), showing a significant increasing trend. Pearson correlation indicated that most soil physiochemical factors showed a significant correlation with SOC (p &l... [more]

The zigzag (ZZ) classifier is a sorting and classification device with a wide range of applications (e.g. recycling, food industry). Due to the possible variation of geometry and process settings, the apparatus is used for various windows of operation due to the specifications of the separation (e.g. cut sizes from 100 µm to several decimetres, compact and fluffy materials as well as foils). Since the ZZ classifier gains more and more interest in recycling applications, it is discussed in this paper, with regards to its design, mode of operation, influencing parameters and the research to date. Research on the ZZ-classifier has been ongoing on for more than 50 years and can be divided into mainly experimental studies and modelling approaches.

The hot jet of an aero engine is one of the main radiation sources of infrared detectors in 3−5 microwave bands. Transverse jets were introduced into a hot jet to enhance mixing and reduce the infrared radiation characteristics. This proved to be a high-efficiency and low-resistance infrared suppression technology. The steady-state distribution of temperature data was simulated, which was needed in the thermal radiation calculation. The radiation characteristics were calculated based on the anti-Monte Carlo method in 3−5 microwave bands. The mechanics of enhanced mixing by a rectangular nozzle or transverse jets was investigated with the LES simulation. Compared with an axisymmetric nozzle, a rectangular nozzle induced abundant counter-rotating vortex pairs (CVP), hairpins, shears, and helical vortexes, which resulted in significant mixing enhancement and infrared radiation decrease of the hot jets. Further, circumferential transverse jets of different types were introduced downstream... [more]

“High-performance thin-layer chromatography (HPTLC)” methods for gefitinib (GFT) estimation are scarce in the literature. In addition, greener analytical techniques for GFT estimation are also lacking in the literature. Accordingly, an attempt was undertaken to invent and validate a sensitive and greener normal-phase HPTLC method for GFT analysis in commercial tablets in comparison to the routine normal-phase HPTLC method. The greenness index for both methods was assessed using “Analytical GREENness (AGREE)” methodology. GFT detection was carried out using both methods at 332.0 nm. In the 30−700 ng/band and 20−1400 ng/band ranges, the routine and greener HPTLC assays were linear for GFT estimation. The greener HPTLC method was highly sensitive, more accurate, more precise, and more robust than the routine HPTLC assay for GFT estimation. Both methods were able to detect GFT in the presence of its degradation products, suggesting the stability-indicating property of both methods. The ass... [more]

The Glycemic Index (GI) has been described by an official method ISO (International Organization for Standardization) 26642:2010 for labeling purposes. The development of in vitro methods for GI measurement has faced significant challenges. Mass transfer and reaction engineering theory may assist in providing a quantitative understanding of in vitro starch digestion and glycemic response from an engineering point of view. We suggest that in vitro GI measurements should consider the mouth and the stomach in terms of fluid mechanics, mass transfer, length scale changes, and food-solvent reactions, and might consider a significant role for the intestine as an absorption system for the glucose that is generated before the intestine. Applying mass transfer and reaction engineering theory may be useful to understand quantitative studies of in vitro GI measurements. The relative importance of reactions and mass-transfer has been estimated from literature measurements through estimating the Da... [more]