Roscoe rhizomes have been associated with multiple health benefits, such as blocking blood clotting, digestive and antinausea effects and aid in respiratory conditions. These effects have been linked with their polyphenolic main metabolites, gingerols and shogaols. Herewith, we report a detailed study on the polyphenolic profile and in the contents of main gingerols and shogaol as well as the antioxidant activity of extracts from Z. officinale rhizomes (n = 17) produced in Costa Rica. Using UPLC-QTOF-ESI MS, a total of 34 polyphenols were identified, grouped in 12 types of structures. In addition, our findings on the main metabolites using UPLC-DAD show all rhizomes complying with total gingerols (TG) content established by the United States Pharmacopeia (USP). At an individual level, samples SR-1 and NR-4 show the higher contents and also exhibit the highest Folin−Ciocalteu (FC) reducing capacity results as well as the best DPPH antioxidant values. In addition, Pearson correlation ana... [more]

This article describes a methodical framework that combines two specific methods of Lean management, namely the ABC method and the MRP planning method. The article further argues that combining the ABC inventory method with subsequent MRP planning is beneficial if the combination is implemented in practice. To demonstrate the benefits, the framework is tested using a case study company. The presented case-study problem is to reduce the number of changeover downtimes in the environment of an engineering production company. The researched company deals with the problem of setting up production lines in a way to minimize the number of downtimes within one work shift. Within the solution, four possible variants of the production plan are presented. By combining the ABC and MRP methods, up to four changeovers can be saved, which in financial terms represents a saving of about EUR 450,000 per year.

Hydrogenation of ethylene carbonate (EC) to co-produce methanol (MeOH) and ethylene glycol (EG) offers an atomically economic route for CO2 utilization. Herein, aided with bench and pilot plant data, we established engineering a kinetics model and multiscale reactor models for heterogeneous EC hydrogenation using representative industrial-type reactors. Model-based analysis indicates that single-stage adiabatic reactors, despite a moderate temperature rise of 12 K, suffer from a narrow operational window delimited by EC condensation at lower temperatures and intense secondary EG hydrogenation at higher temperatures. Boiling water cooled multi-tubular reactors feature near-isothermal operation and exhibit better operability, especially under high pressure and low space velocity. Conduction oil-cooled reactors show U-type axial temperature profiles, rendering even wider operational windows regarding coolant temperatures than the water-cooled reactor. The revelation of operational charact... [more]

The use of wind power generation can reduce the pollution in the environment and solve the problem of power shortages on offshore islands, grasslands, pastoral areas, mountain areas, and highlands. Wind speed forecasting plays a significant role in wind farms. It can improve economic and social benefits and make an operation schedule for wind turbines on large wind farms. This paper proposes a combined model based on the existing artificial neural network algorithms for wind speed forecasting at different heights. We first use the wavelet threshold method with the original wind speed dataset for noise reduction. After that, the three artificial neural networks, extreme learning machine (ELM), Elman neural network, and Long Short-term Memory (LSTM) neural network, are applied for wind speed forecasting. In addition, the variance reciprocal method and social cognitive optimization (SCO) algorithm are used to optimize the weight coefficients of the combined model. In order to evaluate the... [more]

Outer edge bending is already used on the axial fan blades of air conditioners, reducing the leakage flow loss at the blade tip and suppressing the tip vortex development, thereby improving fan aerodynamic and acoustic performance. However, there are few studies on the multi-parameter design and optimization of this complicated structure, and most studies only focus on the overall sound pressure level rather than the sound quality when evaluating the fan noise. This study investigated the effects of outer edge bending structure on the aerodynamic performance and sound quality of air conditioners’ axial fans by experiments and numerical methods. Based on the orthogonal design method, the effects of three bending parameters, the circumferential starting angle, radial relative position, and the bending degree effects on the performance of the axial flow fan blade were analyzed, and the best efficiency scheme was selected. A comparative analysis of the preferred and the original bending sc... [more]

In order to solve the inaccuracy in the calculation of the wellbore pressure distribution caused by large liquid production in the Donghai gas field, the gas−liquid production conditions of the Donghai gas field were simulated with indoor experiments, and the flow patterns for different pipe diameters, different inclinations, and different flow patterns were systematically analyzed using a flow pattern discrimination method, liquid holdup calculation method, and pressure drop calculation method. Using the experimental data, the division methods for different flow patterns were screened. Finally, based on the fact that the change trend for the flow patterns was consistent, the Kaya−Sarica−Brill method was selected to establish the flow pattern discrimination formula. According to the calculation method for the Mukherjee and Brill (M−B) liquid holdup, the M−B model was re-established according to a 75 mm pipe diameter and 60 mm pipe diameter using the instantaneous liquid holdup measured... [more]

Due to the diseases that people face today, scientists dedicate a part of their research to the synthesis, characterization, and study of functional compounds for controlled drug delivery. On the one hand, resorcinarenes are macrocycles obtained by condensation reactions of resorcinol and aldehyde. They include an upper and a lower rim functioning with different groups that confer solubility to the macrocycle and favor interactions with other compounds, therefore the hydroxyl groups on the upper rim improve the formation of hydrogen bonds. Additionally, resorcinarenes feature a cavity studied for forming host-guest complexes. SBA-15, on the other hand, is a mesoporous silica characterized by ordered pores in its structure and a large surface area. As a result of its properties, it has been used for several purposes, including absorbents, drug delivery, catalysis, and environmental processes. This review shows the recent advances in synthesis methods, characterization, micelle formation... [more]

With the increase in demand for plastic use, waste plastic (WP) management remains a challenge in the contemporary world due to the lack of sustainable efforts to tackle it. The increment in WPs is proportional to man’s demand and use of plastics, and these come along with environmental challenges. This increase in WPs, and the resulting environmental consequences are mainly due to the characteristic biodegradation properties of plastics. Landfilling, pollution, groundwater contamination, incineration, and blockage of drainages are common environmental challenges associated with WPs. The bulk of these WPs constitutes polyethene (PE), polyethene terephthalate (PET) and polystyrene (PS). Pyrolysis is an eco-friendly thermo-chemical waste plastic treatment solution for valuable product recovery, preferred over landfilling and incineration solutions. In this extensive review, a critical investigation on waste plastic catalytic pyrolysis (WPCP) is performed, including catalyst and non-catal... [more]

Urban forests are key to mitigating the Urban Heat Island Effect, which contributes to temperature increases in urban areas. However, the trees in these forests are usually under stress because urban soil is typically degraded. Biochar/compost amendments help with soil management by improving the physiochemical properties and bacterial communities of soil. Here, we compared the physiochemical properties and bacterial communities before and after (1) biochar-only and (2) biochar-based compost amendments. Our results suggested that biochar-only application did not improve soil properties after 1 year of treatment, whereas in the biochar-based compost treatment, the soil properties and bacterial communities changed after just four months. The increase in potassium and decrease in organic material, calcium, and available phosphorus in the soil of the former treatment indicated that the nutrient uptake of its trees had improved. Although there was no significant variation in the soil’s tota... [more]

Solid-liquid two-phase flow centrifugal pumps are widely used in many fields closely related to economic development, such as energy exploitation, and the petrochemical industry. Many scholars have studied the influence of solid particles with different parameters on the transportation performance of centrifugal pumps but have mainly focused on the study of low-concentration single-component particles, and the research on the transportation of high-concentration binary mixture particles in centrifugal pumps is insufficient. In this paper, two kinds of glass beads (0.4 mm and 2 mm) were mixed as a solid phase medium, representing small particles and large particles, respectively. The effects of a high concentration (Cv = 10%) of binary mixture particles on the transport and wear characteristics of a solid-liquid centrifugal pump were analyzed by simulation and experiment. Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) and Archard wear model were used for simulation, real... [more]

The integrated supercritical fluid extraction−impregnation process (SFE-SSI) was performed to fabricate material with antiviral properties against the herpes simplex virus (HSV). Cotton gauze and starch/chitosan polymer films (SCF) were impregnated with components extracted from Melissa officinalis at 10 MPa and 40 °C using a green medium, supercritical carbon dioxide (scCO2). The influences of the processing mode regarding the flow of the supercritical fluid through the system, and the mass ratio of the plant material and the solid carrier, on the impregnation yield of M. officinalis extract were studied. The results revealed that the introduction of a fresh amount of CO2 into the system enabled the highest impregnation yield of 2.24% for cotton gauze and 8.71% for SCF. The presence of M. officinalis extract on the surface of both impregnated cotton gaze and SCF was confirmed by FTIR and GC analyses after the re-extraction of the impregnated samples. The M. officinalis impregnated mat... [more]

In practice, the modeling and analysis of nonlinear rotor-bearing systems are difficult due to the nonlinearity and complexity. In the previous studies, finite element simulation and mathematical modeling methods are mostly adopted to conduct the analysis. However, due to the time-consuming problem in finite element simulation and the lack of sufficient prior knowledge in mathematical modeling, the traditional method is difficult to establish the representation model. In order to overcome this issue, in this study, a data-driven model referred to as the NARX (Nonlinear Auto-Regressive with exogenous inputs) model is introduced to conduct the modeling and analysis of the rotor-bearing system. The identification of the NARX model requires random excitation as the system input, while the input signal of the rotor system is harmonics. Therefore, a time-domain frequency sweep modeling method is proposed in this paper by introducing the rotating speed into the coefficients function expressio... [more]

Age-related macular degeneration (AMD) is related to central visual loss in elderly people and, based on the increment in the percentage of the aging population, the number of people suffering from AMD could increase. AMD is initiated by retinal pigment epithelium (RPE) cell death, finally leading to neovascularization in the macula lutea. AMD is an uncurable disease, but the symptom can be suppressed. The current therapy of AMD can be classified into four types: device-based treatment, anti-inflammatory drug treatment, anti-vascular endothelial growth factor treatment, and natural product treatment. All these therapies have adverse effects, however early AMD therapy used with products has several advantages, as it can prevent RPE cell apoptosis in safe doses. Cell death (apoptosis) is caused by various factors, such as oxidative stress, inflammation, carbonyl stress, and a deficiency in essential components for cells, and RPE cell death is related to oxidative stress, inflammation, an... [more]

Valorization of lignocellulosic materials into value-added biobased chemicals is attracting increasing attention in the sustainable chemical industry. As an important building block, furoic acid has been commonly utilized to manufacture polymers, flavors, perfumes, bactericides, fungicides, etc. It is generally produced through the selective oxidation of furfural. In this study, we provide the results of the conversion of biomass-based xylose to furoic acid in a chemoenzymatic cascade reaction with the use of a heterogeneous chemocatalyst and a dehydrogenase biocatalyst. For this purpose, NaOH-treated waste shrimp shell was used as a biobased carrier to prepare high activity and thermostability of biobased solid acid catalysts (Sn-DAT-SS) for the dehydration of corncob-valorized xylose into furfural at 170 °C in 30 min. Subsequently, xylose-derived furfural and its derivative furfuryl alcohol were wholly oxidized into furoic acid with whole cells of E. coli HMFOMUT at 30 °C and pH 7.0.... [more]

Implementation of flue gas waste heat recovery is an effective way to improve the energy utilization of marine engines. This paper aims to model and optimize a marine four-stroke dual-fuel (DF) engine coupled with a flue gas waste heat recovery system. Firstly, the DF engine and waste heat recovery system were respectively modeled in GT-Power and Simulink environments and verified with experimental data. Then, a regression model was built using the response surface method, with the intake temperature, compression ratio, and pilot fuel injection timing as input parameters and parametric analysis was performed. Finally, multi-objective optimization of the waste heat recovery system was performed using a genetic algorithm. The result showed that the optimal solution is obtained when the intake temperature is 306.18 K, the geometric compression ratio is 14.4, and the pilot fuel injection timing is −16.68 °CA after the top dead center. The corresponding brake-specific fuel consumption was 1... [more]

With the increasing demand for security and privacy, identity recognition based on the unique biometric features of ECG signals is gaining more and more attention. This paper proposes a feature reuse residual network (FRRNet) model to address the problem that the recognition accuracy of conventional ECG identification methods decreases with the increase in the number of testing samples at different moments or in different heartbeat cycles. The residual module of the proposed FRRNet model uses the adding layers of max pooling (MP) and average pooling (AP), and the proposed model splices the deep network with the shallow network to reduce noise extraction and enhance feature reuse. The FRRNet model is tested on 20 and 47 subjects under the MIT-BIH dataset, and its recognition accuracy is 99.32% and 100%, respectively. Additionally, the FRRNet model is tested on 50 and 87 subjects under the PhysioNet/Computing in Cardiology Challenge 2017 (CinC_2017) dataset, and its recognition accuracy... [more]

The condition of the bearing is closely related to the condition and remaining life of the rotating machine. Targeting the problem of the large number of harmonic signals and noise signals during the operation of rolling bearings, and given that it is difficult to identify the fault in time, an adaptive orthogonal matching pursuit algorithm (OMP) and an improved K-singular value decomposition (K-SVD) for bearing fault feature extraction are proposed. An adaptive OMP algorithm is applied, which uses the Fourier dictionary to improve the solution method of the OMP algorithm so that it can separate the harmonic components in the signal faster and more accurately. At the same time, the stopping criterion of the adaptive sparsity is improved in dictionary learning. There is no need to manually set the sparsity in the algorithm initialization process, which avoids the problem of algorithm performance degradation due to improper sparsity settings, and improves the efficiency of the K-SVD algo... [more]

There have been numerous studies highlighting the efficacy of various bacteriophages (phages) and phage cocktails in the reduction of pathogens in food. Despite approval from legislative bodies permitting phage use in food processing environments, applied via spray or dip, there is still no information on which spray parameters should be used for successful implementation. The study here investigates phage survival diluted to 1% in distilled water (dH2O) and prepared bottled water (PBW), followed by a subsequent spray application through a fixed nozzle (530 μm) and strainer size (74 × 74 μm), with pressures of 3, 5, and 6 Bar. The survival of the phage was determined through sampling the outputs of the spray system and performing double agar overlay plaque assays. PBW decreased the phage concentration (p = 0.18) more than the dH2O (p = 0.73) prior to spray application. It was found that the PBW phage solution was less affected by the various spray parameters (p = 0.045) than the dH2O (... [more]

Aluminum−silicon (Al−Si) alloys are the most commonly cast aluminum alloys. Fe is the most deleterious element for Al−Si die casting alloys, as its existence causes the precipitation of substantial intermetallics that result in the unsatisfactory mechanical performance of the alloy, such as its ductility. Hence, controlling the morphology and formation of the AlFeSi phase, particularly the β-AlFeSi phase, is vital for improving the ductility of Al−Si die casting alloys. Herein, Ca was added to the A380 alloy, and the morphological changes resulting from the influence of Ca on the AlFeSi phase were characterized. The outcomes revealed that according to different cooling rates, specific amounts of Ca addition (0.01−0.1 wt.%) were capable of refining α-AlFeSi and β-AlFeSi morphology and transforming the β-AlFeSi phase into α-AlFeSi. Moreover, Ca addition could also modify eutectic silicon. The transformation mechanism and refining role of Ca in AlFeSi and the different morphologies of Al2... [more]

This article presents a cloud-based system for the on-line monitoring of tool conditions in end milling. The novelty of this research is the developed system that connects the IoT (Internet of Things) platform for the monitoring of tool conditions in the cloud to the machine tool and optical system for the detection of cutting chip size. The optical system takes care of the acquisition and transfer of signals regarding chip size to the IoT application, where they are used as an indicator for the determination of tool conditions. In addition, the novelty of the presented approach is in the artificial intelligence integrated into the platform, which monitors a tool’s condition through identification of the current cutting force trend and protects the tool against excessive loading by correcting process parameters. The practical significance of the research is that it is a new system for fast tool condition monitoring, which ensures savings, reduces investment costs due to the use of a mo... [more]

We live in the big data era, in which a large amount of information is continuously created, registering all kinds of events, such as those generated in the design, planning, control, and execution of manufacturing, logistics, and supply chain processes [...]

In the stochastic reconstruction of petroleum fractions, the domain configuration for parameters is of great significance to the performance of the model in terms of accuracy and convergence. Based on the stochastic reconstruction model of gas oils, this work investigates the influence of different domains on the simulating accuracy, the convergence rate and the ability to predict detailed composition. In this paper, the parameters to be optimized in the model include histogram distributions and gamma distributions, which are used to represent the structural attributes. In each histogram distribution, the parameters are real numbers between zero and one that should increase progressively. The mean and shape parameters are used as the tuning parameters for gamma distribution. As for the mean, the lower and upper boundaries are configured as fixed values that depend on the predefined values of the structural attributes. For the shape parameter, multiple cases are considered for its upper... [more]

The progress of high-efficiency non-precious metal anode catalysts for direct seawater splitting is of great importance. However, due to the slow oxygen evolution reaction (OER) kinetics, competition of chlorine evolution reaction (ClER), and corrosion of chloride ions on the anode, the direct seawater splitting faces many challenges. Herein, we develop a perovskite@NiFe layered double hydroxide composite for anode catalyst based on Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF) and NiFe layered double hydroxide (NiFe-LDH) heterostructure. The optimized BSCF@CeO2@NiFe exhibits excellent OER activity, with the potential at 100 mA cm−2 (Ej = 100) being 1.62 V in the alkaline natural seawater. Moreover, the electrolytic cell composed of BSCF@CeO2@NiFe anode shows an excellent stability, with negligible attenuation during the long-term overall seawater splitting with the remarkable self-recovery ability in the initial operation stage, and the direct seawater splitting potential increasing by about 30 mV at... [more]

The purpose of this paper is to investigate the feasibility of a wind−solar hybrid system on and off-grid power system for electricity generation at a selected location in Somalia using the renewable energy optimization software HOMER. The simulation model was successfully applied to find the best simulation results based on the energy-efficient system for the specific load. The technical and economic performance of an on-grid and stand-alone combination of 25 kW wind power and 60 kW solar photovoltaic was investigated. Since the city of Cadaado has not yet installed its own standard modern electricity grid and due to the great need to reduce energy costs in Somalia, a feasibility study was conducted on how to supply electricity to a sampled residential consumption. Based on the basic characteristics of renewable energy sources in central Somalia, the on-grid wind and solar photovoltaic systems could be economically feasible.

Biodiesel can substitute for conventional diesel fuel and contribute to the decarbonization of the transportation sector. To improve biodiesel sustainability and decrease production costs, low-grade fats such as non-edible animal fats must be used. Animal fats are mixed with tissues which must be removed before alcoholysis to avoid biodiesel contamination with nitrogen and phosphorus-containing compounds. Biodiesel was produced by the methanolysis of beef tallow and beef tallow/soybean oil mixtures over calcium heterogeneous catalysts obtained by the calcination of scallop shells. The tallow from fatty bovine tissues was extracted using boiling water, dry microwave treatment, and acetone extraction. The thermal stability and the moisture content of the extracted fats were evaluated by thermogravimetry. The thermograms of fats revealed that microwave treatment, which was faster (3 min instead of 40 min for boiling water and 240 min for acetone extraction) and had the lowest energy consu... [more]