Injection molding (IM) is an ideal technique for the low-cost mass production of moderately thick plane lenses (MTPLs). However, the optical performance of injection molded MTPL is seriously degraded by the warpage and sink marks induced during the molding process with complex historical thermal field changes. Thus, it is essential that the processing parameters utilized in the molding process are properly assigned. And the challenges are further compounded when considering the MTPL molding energy consumption. This paper presents a set of procedures for the optimization of injection molding process parameters, with warpage, sink marks reflecting the optical performance, and clamping force reflecting the molding energy consumption as the optimization objectives. First, the orthogonal experiment was carried out with the Taguchi method, and the S/N response shows that these three objectives cannot reach the optimal values simultaneously. Second, considering the experimental data scale, th... [more]

The effects of different spargers on the hydrodynamics and mass transfer of an airlift loop reactor were investigated. The gas holdup, liquid loop velocity, and volumetric mass transfer coefficient of the reactor were tested using a ring orifice distributor and a jet nozzle. The study was conducted in a 6 m high airlift loop reactor at a superficial gas velocity of 0.01~0.04 m/s, and the superficial liquid velocity was maintained at 0.0154 m/s. The results showed that using the jet nozzle provided a higher gas holdup, liquid loop velocity, and mass transfer. When the superficial gas velocity was less than 0.0325 m/s, the liquid loop velocity generated by the jet nozzle was approximately 1.1-fold higher than that generated by the ring orifice distributor, and the disparity in gas holdup between the riser and downcomer enhanced the power of liquid circulation. When the superficial gas velocity was more than 0.0325 m/s, the jet kinetic power dominated the improvement in the liquid loop ve... [more]

This study investigated the chemical compositions and inhibitory activities of essential oils (EOs) of Salix babylonica from Vietnam. The gas chromatography−mass spectrometry (GC/MS) system was used to analyze the chemical compositions of Salix babylonica essential oils. A total of twenty-eight and thirty-one compounds were identified in essential oils of the leaves and bark, among which many chemical compositions were identified for the first time in this plant. Salix babylonica essential oils demonstrated antibacterial activities against Gram-negative strains such as Pseudomonas aeruginosa (PA) and Escherichia coli and Gram-positive strains such as Staphylococcus aureus (SA), and demonstrated anti-cancer activities against three cancer cell lines (HepG2, MCF-7 cell, and A549). The evaluation of the ability to inhibit three strains of microorganisms and inhibit the growth of three cancer cell lines was first conducted using essential oils extracted from the plant species S. babylonica... [more]

Recently, many efforts have been made to reuse spent batteries in response to the growing demand for sustainable materials production. In parallel, supercapacitors have attracted significant attention for their use in addressing some of the limitations of conventional capacitors and batteries. In this context, this paper describes the preparation, characterization, and supercapacitive performance evaluation of carbon-graphite (CG) electrodes obtained from spent zinc−carbon batteries and modified with polypyrrole (PPY) and polyaniline (PANI). The parameters of PPY and PANI electropolymerization were optimized. CG/PPY, CG/PANI, and CG/PPY/PANI electrodes were obtained to compare their electrochemical responses. Cyclic voltammetry (CV), galvanostatic charge−discharge curves (GCDC), and electrochemical impedance spectroscopy (EIS) were used to evaluate the pseudocapacitive properties of the CG/PPY/PANI-modified electrode. The CG/PPY/PANI electrode showed a specific capacitance of 3416 mF c... [more]

Energy consumption forecasting plays an important role in energy management, conservation, and optimization in manufacturing companies. Aiming at the tin smelting process with multiple types of energy consumption and a strong coupling with energy consumption, the traditional prediction model cannot be applied to the multi-output problem. Moreover, the data collection frequency of different processes is inconsistent, resulting in few effective data samples and strong nonlinearity. In this paper, we propose a multi-kernel multi-output support vector regression model optimized based on a differential evolutionary algorithm for the prediction of multiple types of energy consumption in tin smelting. Redundant feature variables are eliminated using the distance correlation coefficient method, multi-kernel learning is introduced to improve the multi-output support vector regression model, and a differential evolutionary algorithm is used to optimize the model hyperparameters. The validity and... [more]

Improving the hydrophilicity and mechanical strength of membranes in water treatment applications remains challenging. In this study, modified vermiculite (VT-M) and a hydrophilic polyvinylpyrrolidone (PVP) were introduced into a polyethyleneimine-functionalized polyvinylidene fluoride composite membrane (PVDF/PEI) to prepare a comprehensively modified mixed-matrix PVDF composite membrane adsorbent that exhibited high mechanical strength and excellent hydrophilicity. The modified composite membrane featured good tensile properties, with a maximum tensile strength of 2.093 MPa, which was 2.5 times that of the PVDF/PEI membrane. After 7 s, the water contact angle of the composite membrane decreased to 0°, leading to significantly improved hydrophilicity. The modified composite membrane exhibited excellent adsorption selectivity for mercury ions, with a fitted maximum adsorption capacity of 807 mg/g. In a mixed-metal ion solution, the selectivity of the membrane for Hg(II) ions was 1.2 ×... [more]

It is known that highly efficient catalysts for the catalytic oxidation of aromatic hydrocarbons can be obtained based on magnetic nanoparticles. The development of nanosized magnetically controlled catalysts for the oxidation of aromatic hydrocarbons with oxygen deserves especially close attention in the territory of the Republic of Kazakhstan, which does not have its own industrial production of oxygen-containing compounds. The aim of this work is to create catalysts based on Fe and Co nanoparticles stabilized with polymers: polyvinylpyrrolidone, chitosan, and polyethylenimine, study them by methods of physico-chemical research, and conduct preliminary tests of catalysts to predict their effectiveness. Magnetic nanoparticles were prepared by the co-precipitation method. Based on the results of the SEM analysis, it was concluded that polymers form composites together with metal nanocrystals. According to preliminary data, the most efficient oxidation of phenol in a non-flowing glass g... [more]

In geopolymer bricks (GPBs), fly ash content, which is waste from power plants, is converted into bricks by chemical treatment. GPBs can be dried by using appropriate curing methods. Conventionally, electric oven curing is one of the prominent methods. Using a solar dryer instead of an electric oven provides the added advantage of saving high-grade electrical energy. So, in this work, a solar dryer with the phase change material (PCM) paraffin wax and without a PCM is used for curing applications. GPBs gain an added advantage when compared to conventional bricks like cement and sand bricks in terms of strength. A GPB has been taken as a specimen for comparing the compressive strength, tensile split strength, and flexural strength of electrical-energy-based curing and solar-energy-based curing. It has been experimentally observed that solar-energy-based curing with and without a PCM exhibits higher compressive strength, higher tensile split strength, and flexural strength when compared... [more]

Xylose is nowadays converted into xylitol, a popular special chemical sweetener. Xylitol can be used not only in the pharmaceutical and food industries, but also in cosmetics and synthetic resins because of its countless properties. Conventionally, xylitol is produced by slurry reactors operating in batch with dispersed or supported catalysts. Hydrogen is continuously fed to maintain a constant pressure. In this work, the kinetics of the reaction were investigated to find the optimal operating conditions to minimize the by-products obtained. Given the great performances shown by the new Ru/SiO2 sol−gel derived catalyst in glucose hydrogenation, in this work the mentioned catalyst was tested in the hydrogenation of xylose to xylitol both in batch and in continuous production to prove its stability and activity.

Operating time series data collected and stored in historian must be managed to extract their full potential. Part 1 of this paper proposed a structured way (a sophisticated approach) to process industrial data; this first part explains in detail the data processing framework used as the basis for the costing analysis present in the second part of this series. The framework considers the analysis scope definition, data management steps, and operating regimes detection and identification. The added value of this proposed framework is demonstrated in Part 2 via the use of cost accounting for operational problem-solving (debottlenecking), i.e., its practicality is validated via its application alongside a cost analysis on the brownstock washing department of a kraft pulp mill. The traditional debottlenecking approach assumes a single operating condition considering that operating regimes allow for a much more sophisticated debottlenecking study of the washing department. With the use of o... [more]

In this paper, a closed hydrostatic drive powertrain (HSDP) composed of an engine, a variable pump, a variable motor, and an energy-efficient adaptive speed-regulating controller (ADC) based on power following is proposed and investigated. The controller can more than guarantee accurate regulation of motor speed through online efficiency estimation based on established loss models of the pump and the motor. It also facilitates the optimal efficiency control of the engine and hydrostatic system through two redundant control freedoms of the HSDP system, making an energy-saving adjustment of the motor speed. At the same time, the controller can prevent engine overload stall and high system pressure by limiting the displacement of the pumps and motors in real time based on the system loads to improve the automatic adaptability of the system to varying loads. Field testing experiments performed by means of a heavy transportation vehicle under different conditions were conducted to verify th... [more]

Betulin is a birch bark-derived lupane-type pentacyclic triterpene with a wide spectrum of biological activities. Given their enhanced antiproliferative potential and enhanced pharmacological profile, betulin derivatives are continuously investigated in scientific studies. The objective of the current study was to in vitro assess the antiproliferative properties of novel synthesized 1,2,4-triazole derivatives of diacetyl betulin. The compounds were investigated using three cancer cell lines: A375 (melanoma), MCF-7 (breast cancer), HT-29 (colorectal cancer), and HaCaT (human keratinocytes). Bet-TZ1 had the lowest recorded IC50 values (ranging from 22.41 to 46.92 μM after 48 h of exposure) than its precursor and other tested compounds in every scenario, with the highest cytotoxicity against the A375 cell line. Bet-TZ3 demonstrated comparable cytotoxicity to the previously mentioned compound, with an IC50 of 34.34 μM against A375. Both compounds caused apoptosis in tested cells, by induci... [more]

In this study, 2% chitosan (Ch) (w/v) was enriched with 1% Lippia javanica, Syzygium cordatum, and Ximenia caffra extract to form Ch+L, Ch+S, and Ch+X, respectively. The control film was the chitosan (Ch) film without plant extracts. The composite films were assessed for their antifungal ability using the agar diffusion method against economically relevant plant pathogens, Botrytis cinerea, and Penicillium expansum. These chitosan films were further evaluated using an X-ray diffractometer and scanning electron microscope, and their physical and mechanical properties were also assessed. The medicinal plants in the chitosan matrix had the highest inhibition zone (10 mm) against P. expansum, while the chitosan-only films had the lowest inhibition zone (3.3 mm). Notably, Ch+S and Ch+X films had the highest inhibition zone (10 mm) against B. cinerea, while chitosan-only films did not avert the spread of B. cinerea. Ch+L films had the highest film thickness (0.189 mm), density (1.62 g·cm3),... [more]

This study presents an aerostructural optimization process for wind turbine blades aimed at enhancing the turbine’s performance. The optimization framework integrates DAFoam as the computational fluid dynamics (CFD) solver, TACS as the finite element method (FEM) solver, Mphys for fluid−structure coupling, and SNOPT as the optimizer within the OpenMDAO framework. The objective is to simultaneously increase the torque generated by the wind turbine while decreasing the mass of the blade, thereby improving its efficiency. The design variables in this optimization process are the blade shape and panel thickness. The aerodynamic objective function is torque, a key performance indicator for wind turbine efficiency. The structural objective function is the blade mass, as reducing mass is essential to minimize material and manufacturing costs. The optimization process utilizes the integrated capabilities of DAFoam, TACS, Mphys, and SNOPT to iteratively evaluate and modify the blade shape and p... [more]

This study covers the critical concerns related to the sizing, selection, installation, maintenance, and testing of pressure safety valves (PSVs). The aim is to ensure the safety of pressurized systems, hydrostatic transmission systems, and hydraulic plants, including process plants, thermal power plants, and nuclear reactor systems. PSVs are devices that ensure the safety and reliability of pressurized vessels, lines, and systems during overpressure events. The task of selecting which PSV features are of greatest value for a specific purpose is complex—especially in the design of a high-pressure experimental thermal−hydraulic facility for hydrostatic and transient testing of the reactor system—when the systems are in the design and development phases and require qualification and demonstration to prove that they have reached a given level of technological readiness. The present study highlights the required steps for users to follow the associated rules, guidelines, and recommendation... [more]

Coal is complex as it includes organic matter (macerals) and inorganic matter (minerals) [...]

This paper addresses the pressing need for advanced simulation tools in electric phasor modeling and Smart Grid-Power to X systems. The motivation for this study stems from the critical importance of enhancing the balance between performance and the detailed dynamic representation of the system behavior in the simulations. The identified problem lies in the absence of a comprehensive framework that seamlessly integrates electric phasor DQ0 components into a multi-purpose object-oriented environment. The primary objective of this research is to develop and introduce two simulation libraries, centered around the core component, Electric_DQ0. These libraries aim to establish a robust phasor-based framework, incorporating essential electric components such as sources, loads, branches, power converters, and electric machines. The main goal is to enable dynamic frequency and voltage simulations, particularly focusing on transients in alternators and facilitating Voltage and Frequency Rate of... [more]

This paper presents a detailed analysis of the relation between physical characteristics and defects of green coffee beans and the sensory profile that influence the sensory notes of fragrance, aroma, flavor, and aftertaste of coffee. Machine learning models were used to identify the variables of importance and identify the ways in which these variables affect the sensory note of coffee, to determine which algorithm and its hyperparameters have greater precision in determining the sensory values of coffee such as floral, fruity, herbal, nutty, caramel, chocolate, spicy, resinous, pyrolytic, earthy, fermented, and phenolic. The result indicates the relationship and importance that exist between the physical variables, defects, and size of the green coffee bean, with respect to their respective sensory notes. The data of the proposed system demonstrate that by combining the scores of several experts, a precision can be achieved analogously to that obtained by cupping experts; therefore,... [more]

Remanufacturing processes are one of the key pillars of the so-called closed-cycle economy. Unfortunately, the design and organization of such processes pose a significant problem, due to, among other things, the high variability of the process as a consequence of both the degree of wear and tear and the quality of the remanufactured components. This article presents a method for optimizing the flow of the brake caliper remanufacturing process in the MTO (make-to-order) model. For the optimization process, the system dynamics (SD) method, which belongs to a group of simulation methods, was used. The developed model allows, in particular, the prediction of the number of components at the input to the regeneration process and the method of defining the size of the transport batch and evaluating its impact on the length of the production cycle of the batch of regenerated products. The issues of staffing management at individual positions and the organization of transport operations with v... [more]

The real-time and accurate recognition of fruits and vegetables is crucial for the intelligent control of fruit and vegetable robots. In this research, apple picking is selected. This study proposed a lightweight, coupon-product, neural-net terminal YOLO algorithm for apple image recognition. Compared with the YOLO series algorithm, the tiny algorithm shows a strong relationship with the calculation speed. In traditional red fruit detection, the recognition time is generally several seconds, which is unacceptable in the real-time system. In this research, a total of 2000 apple images from different environments are used as a dataset for training and testing. The YOLOv4-tiny model is detailed, instructed, and used for the identification. The indicators, such as F1Score (0.92) and mAP (95.5% average), are analyzed by calculating the loss rate, accuracy rate (96.21%), and recall rate (95.47%). Finally, the algorithm shows good accuracy and high speed (no more than 5 ms) in online real-tim... [more]

Distillation is significantly influenced by energy costs, prompting a need to explore effective strategies for reducing energy consumption. Among these, heat integration is a key approach, but evaluating its efficiency is paramount. Therefore, this study presents exergy as an energy quality indicator, analyzing irreversibility and efficiencies in tetrahydrofuran/water and acetone/chloroform distillations. Both systems have equimolar feed streams, yielding products with 99.99 mol% purity. The simulations are performed using Aspen Plus™, enabling evaluation at the column level, as a standalone process, or from a lean perspective that considers integration opportunities with other plants. The results show that, despite anticipated energy savings from heat integration, economic viability depends on pressure sensitivity. The results demonstrate that heat-integrated extractive distillation for acetone/chloroform raises utility energy consumption. Exergy calculations comparing standalone and... [more]

Although the importance of black copper ores is well established, many topics remain to be studied. This manuscript describes the efforts to improve copper recovery from refractory ores on a pilot scale. Preliminary tests provided the water dose to form a stable and compact agglomerate of 89 L per ton of ore and an acid dosage of 40 kg per ton of ore. The column leaching method resulted in an effluent with 1.63 g/L Cu, a pH of 1.04, and a redox potential of 675 mV (average). Despite the similarities observed in the results, reductant agents were essential to dissolve the MnO4 present in the black copper ore. Thus, the best Mn extraction results were 67.7% using the MnO2:FeSO4 ratio of 1:3. Additionally, the kinetics of leaching are slower than in an industrial operation. The copper ore under study required more than 65 days of leaching to reach the maximum copper recovery. Finally, the total recovery of copper (including washing and resting time) indicates that the maximum value was re... [more]

To accurately evaluate the size and distribution characteristics of the emission particles exhausted from in-use motor vehicle engines, we independently developed a condensation particle counter (CPC) known as BHCPC. It was calibrated by conducting the calibration procedures stated in the International Standard ISO 27981. After calibration, we conducted on-site measurements and offline sampling analysis of soot particles exhausted from different engines at a motor vehicle inspection center. The calibration results show that the detection efficiency is 90% when the particle diameter is 20.6 nm and the startup response time of the instrument is 3.53 s. The experiment results show that the self-developed BHCPC demonstrates good consistency in measuring particle-number concentration (PNC) in motor vehicle exhaust, with significant count fluctuations only occurring when PNC is higher than 25,000 P/cc. Under idle conditions, motor vehicles compliant with China VI emission regulations exhibit... [more]

A combined approach of Latin hypercube sampling and K-means clustering is proposed in this study to address the uncertainty issue in wind and solar power output. Furthermore, the loads are categorized into three levels: primary load, secondary load, and tertiary load, each with distinct characteristics in terms of demand. Additionally, a load demand response characteristic model is developed by incorporating the dissatisfaction coefficient of electric and thermal loads, which is then integrated into the system’s operational costs. Moreover, an electricity−hydrogen−thermal power system is introduced, and a source-load coordination response mechanism is proposed based on the different levels of demand response characteristics. This mechanism enhances the interaction capability between the power sources and loads, thereby further improving the economic performance of the virtual power plant. Furthermore, the operation economy of the virtual power plant is enhanced by considering the parti... [more]

Solid−liquid separation is a fundamental operation in process engineering and thus an important part of many process chains in the preparation of slurries in the chemical industry and other parts of the industrial environment. For the separation of micron-sized particles which, due to their size, do not settle or settle very slowly in the earth’s gravity field, centrifuges are often used. The preferred choice are often decanter centrifuges because they work continuously and stabilize the process against product fluctuations due to their adjustment possibilities. The design of the apparatus is complex: The main components of the apparatus are the cylindrical-conical bowl, which rotates at a high speed, and a screw located inside the bowl, which rotates in the same direction at a low differential speed to transport the separated solids out of the apparatus. Geometrical properties of the apparatus, as well as the adjustable operating parameters, such as rotational speed or differential sp... [more]