Process Parameters Research Articles

Prolonged retention of luliconazole nanofibers for topical mycotic condition: development, in vitro characterization and antifungal activity against Candida albicans.

An antifungal agent, luliconazole, is commercially available in cream or gel form. The major limitation of these conventional formulations is less residence time at the infection site. The primary objective of this work was to develop luliconazole-loaded polyvinyl alcohol (Luz-PVA) nanofibers for mycotic skin conditions with a longer retention. Luz-PVA nanofibers were prepared by plate electrospinning and optimized for polymer concentration and process parameters. The optimized batch (Trial 5) was prepared by 10% PVA, processed at 22.4 kV applied voltage, and 14 cm plate and spinneret distance to yield thick, uniform, and peelable nanofibers film. There was no interaction observed between Luz and PVA in the FTIR study. DSC and XRD analysis showed that luliconazole was loaded into fabricated nanofibers with a reduced crystallinity. FESEM studies confirmed the smooth, defect-free mats of nanofibers. Luz-PVA nanofibers possessed a tensile strength of 21.8 N and a maximum elongation of 10.8%, representing the excellent elasticity of the scaffolds. For Luz-PVA nanofibers, the sustained and complete drug release was observed in 48 h. In antifungal activity using Candida albicans, the Luz-PVA nanofibers showed a greater zone of inhibition (30.55 ± 0.38 mm and 29.27 ± 0.31 mm) than marketed cream (28.06 ± 0.18 mm and 28.47 ± 0.24 mm) and pure drug (27.57 ± 0.17 mm and 27.50 ± 0.47 mm) at 1% concentration in Sabouraud dextrose agar and yeast malt agar, respectively. Therefore, Luz-PVA nanofibers exhibited good mechanical properties, longer retention time, and better antifungal activity than marketed products and, therefore, can be further examined preclinically as a potential treatment option for topical mycotic infection.

Exploring signal interactions in PWR nuclear power plants through noise-based signal processing

Nuclear power plants operate as complex, interconnected systems with tightly interlinked variables. Monitoring systems within such plants gather data from various process parameters. This paper systematically analyzes key signals in a typical PWR power plant. We develop a dynamic model of the PWR plant encompassing mathematical models for the reactor core, steam generator, pressurizer, turbine, and condenser. This model is rigorously validated against reference data. We use this model to analyze signal perturbations in hypothetical scenarios, employing both time-domain and frequency-domain analyses. Our results demonstrate that noise in one signal noticeably impacts others. Furthermore, the extent of this impact varies depending on the nature of their connection. Direct connections exhibit a higher susceptibility to noise-induced interference, whereas intermediate connections typically show a diminished impact. Through signal analysis, we identify correlated signal pairs, offering insights into processes during abnormal conditions. These findings have implications for enhancing the safety and reliability of nuclear power plant operations.

Electro discharge machining performance of cryogenic heat treated copper electrode

Abstract In this study, the EDM machining performance of a cryogenic heat treated copper electrode was investigated. Within the scope of the study, electrodes selected from copper material were subjected to cryogenic heat treatment with a cycle between [room temperature/ − 184 °C/room temperature]. In the experimental design, the electrode material was changed at two levels: copper electrode (Cu) and cryogenic copper electrode (CCu). Controllable machine parameters, peak current (Ip), active pulse duration (Ton), pulse gap duration (Toff) and gap voltage (Vg) were changed at three levels. The effects of these parameters on outputs such as recast layer thickness (RLT), material removal rate (MRR), electrode wear rate (EWR) and taper angle (TA), which are taken into consideration in determining the processing quality after EDM machining experiments, were taken into account. A total of 18 experiments were carried out on Ti–6Al–4V (Titanium alloy) workpiece with copper electrode. Lower YKTK with combinations of EDM process parameters such as cryogenic copper electrode (CCu), 4 A peak current (Ip), 110 µs active pulse duration (Ton), 72 µs pulse gap time (Toff) and 6 V gap voltage (Vg), It was observed that EWR and TA and higher MRR were obtained.

Utilization of RESOLV with polymer to produce prazosin hydrochloride nanoparticles and optimization of the process parameters

In this study, rapid expansion of a supercritical solution into a Liquid Solvent (RESOLV) was used for the first time to produce pharmaceutical nanoparticles of Prazosin hydrochloride (PRH). The Taguchi method (robust design) was utilized to design the experiments and ensure obtaining the optimal process conditions. The pressure (15–25 MPa), temperature (308–328 K) and nozzle diameter (300–700 μm) effects on the morphology and size distribution of the resulting particles were also examined. The size of the particles decreased from about 40 μm to the range of (252–418 nm). FTIR, DLS, FESEM, XRD, DSC were used to characterize the primary and processed PRH particles. According to DSC investigations, RESOLV-produced PRH showed lower crystallinity than original PRH.

Critical state-of-the-art literature review of surface roughness in incremental sheet forming: A comparative analysis

Incremental sheet forming (ISF) is a controlled and die-less forming process that can produce customized products from the sheets layer by layer using the same setup, i.e., forming tools and machine. This novel and emerging forming technique can potentially be useful as a green aspect of manufacturing by reducing the required power and by saving the resources for producing the components of lightweight materials because material is deformed locally during ISF. The surface quality of the formed parts from sheet material affects the aesthetics aspects, stress concentration, fatigue life and their applicability. This review article aims to provide a state-of-the-art review for various aspects and parameters of ISF process that affect the surface roughness significantly by conducting literature survey quantitatively. Furthermore, the techniques of ISF and roles of various parameters responsible for affecting the surface quality of parts have also been explored for providing the critics for existing literature and setting the further guidelines for the researchers. Various instruments used for measuring the surface roughness of parts formed by ISF has also been discussed. Comparative analysis of exiting literature available in the context of various process parameters, ISF hardware, and surface roughness makes this study comprehensive and exhaustive for the researchers to find the gaps and challenges in this field. The relationship of wall angle with other process parameters can be explored in the future to obtain the desired surface quality of a particular material. Significant parameters responsible for the surface quality have also been discussed critically. Further, the new tool paths can be developed for high surface quality and low forming time. A study on the selection of feed rate for various applications and relation with other parameter is also recommended for the future work. The lubricants with additives can further be tested for high surface quality of ISF. Further, significant study on surface roughness is not conducted on hybrid sheet forming and other advanced variants of ISF (like hot forming, friction stir assisted incremental forming, waterjet forming). It is required to develop the comparisons between the different techniques of ISF. Results also showed that majority of researchers used SPIF technique followed by DSIF and hybrid ISF.

Evaluating the performance of Bi58Sn42 mold produced by material extrusion additive manufacturing system for agile manufacturing

Purpose The purpose of this study is to produce a low-cost sheet metal forming mold made from the low melting point Bi58Sn42 (bismuth) alloy by using an open-source desktop-type material extrusion additive manufacturing system and to evaluate the performance of the additively manufactured mold for low volume sheet metal forming. Thus, it was aimed to develop a fast and inexpensive die tooling methodology for low-volume batch production. Design/methodology/approach Initially, the three-dimensional printing experiments were performed to produce the sheet metal forming mold. The encountered problems during the performed three-dimensional printing experiments were analyzed. Accordingly, both tunings in process parameters (extrusion temperature, extrusion multiplier, printing speed, infill percentage, etc.) and customizations on the extruder head of the available material extrusion additive manufacturing system were made to print the Bi58Sn42 alloy properly. Subsequently, the performance of the additively manufactured mold was evaluated according to the dimensional change that occurred on it during the performed pressing operations. Findings Results showed that the additively manufactured mold was rigid enough and proved to have sufficient strength in sheet metal forming operations for low-volume production. Originality/value Alternative mold production was carried out using open-source material extrusion system for low volume sheet metal part production. Thus, cost effective solution was presented for agile manufacturing.

Effect of Stainless Steel Substrate Preparation on the Adhesion Strength and Morphology of Electrophoretically Deposited Sodium Alginate Coatings

AbstractIn this study, the influence of various mechanical and chemical surface treatments on the adhesion strength and surface properties of sodium alginate coatings electrophoretically deposited (EPD) on 316L stainless steel substrates was investigated. XPS and TEM results revealed the presence of oxide layers containing elements from the substrates, with thicknesses varying from 1 to 45 nm, depending on the treatment used. Most substrates exhibited high roughness and hydrophilic properties (CA with water 62.8–82.6 deg). Sodium alginate coatings with uniform morphology were deposited with the same process parameters, i.e., 5 V and 300 s. The surface topography of the coatings was closely related to that of the substrate on which they were deposited. All coatings exhibited higher hydrophilicity (CA with water 29.5–49.7 deg) compared to the substrates (CA with water 62.8–82.6 deg). The coatings on the etched and anodized substrates demonstrated the highest adhesion strength (class 4B), attributed to the very low oxide layer thickness and the specific substrate surface topography. Mechanical interlocking was identified as the primary adhesion mechanism for these coatings. This work provides insight into optimizing surface treatments for improved adhesion of sodium alginate coatings to stainless steel substrates widely used for temporary bone implants. The results obtained will also be helpful in providing high adhesion of sodium alginate-based composite coatings to steel substrates.

Optimization and Kinetic Study of Manganese Leaching from Pyrolusite Ore in Hydrochloric Acid Solutions with Oxalic Acid

AbstractThe leaching behavior of pyrolusite minerals was examined in hydrochloric acid solutions, including oxalic acid, to evaluate the influence of various experimental conditions. The optimum parameters for the leaching process were found in the first stage, and the process's kinetics were assessed in the second. The concentrations of oxalic acid, hydrochloric acid, and temperature were chosen as independent variables in the optimization experiments, with the central composite design used to analyze the experimental data. The optimum concentrations for oxalic acid, hydrochloric acid, and temperature were determined to be 0.75 mol/L, 1.2 mol/L, and 60 °C, respectively. The leaching rate was determined to be 97.4% for 120 min of response time in optimum situations. The kinetic assessment experiments studied the effects of solid/liquid ratio, particle size, stirring speed, and temperature on the manganese leaching rate from pyrolusite. In the studies, the leaching rate was shown to rise with increasing temperature and stirring speed, as well as with decreasing particle size and solid/liquid ratio. The kinetic analysis revealed that the leaching kinetics matched the mixed kinetic model, and a mathematical model for the leaching process was developed. This process's activation energy was determined to be 29.05 kJ/mol. Graphical Abstract

Applications of simulation modeling in mining project risk management: criteria, algorithm, evaluation

Project risk management in the mining industry is necessary to identify, analyze and reduce uncertainty. The engineering features of mining enterprises, by their nature, require improved risk management tools. This article proves the relevance of creating a simulation model of the production process to reduce uncertainty when making investment decisions. The purpose of the study is to develop an algorithm for deciding on the economic feasibility of creating a simulation experiment. At the same time, the features and patterns of the cases for which the simulation experiment was carried out were studied. Criteria for feasibility assessment of the model introduction based on a qualitative parameters became the central idea for algorithm. The relevance of the formulated algorithm was verified by creating a simulation model of a potassium salt deposit with subsequent optimization of the production process parameters. According to the results of the experiment, the damage from the occurrence of a risk situations was estimated as a decrease in conveyor productivity by 32.6%. The proposed methods made it possible to minimize this risk of stops in the conveyor network and assess the lack of income due to the risk occurrences.

Enhancing torrefaction process efficiency for biochar production from filter cake residue in the sugar industry

The torrefaction process is a promising technique for enhancing the quality of solid biomass fuels. This study investigates the effects of torrefaction on biochar produced from filter cake residue, a byproduct of the sugar industry. The primary objectives were to evaluate the impact of process parameters on biochar properties and identify optimal conditions for maximizing the higher heating value (HHV). Filter cake residue was subjected to torrefaction at temperatures ranging from 220-340°C under an inert atmosphere. The influence of particle size (20, 60, and 100 mesh), nitrogen flow rate (20-30 ml/min), temperature (220-340°C), and residence time (30-90 min) on biochar properties was examined using response surface methodology. Proximate analysis revealed that torrefaction significantly reduced moisture, volatile matter, and ash content while increasing fixed carbon content. The maximum HHV of 21.9571 MJ/kg was achieved at a particle size of 20 mesh, nitrogen flow rate of 25 ml/min, temperature of 340°C, and residence time of 60 min. The experimental results agreed with predicted values from the developed models, with an average error of 3.64%. Optimal torrefaction conditions were determined to be a particle size of 21.77 mesh, nitrogen flow rate of 22.50 ml/min, temperature of 311.13°C, and residence time of 42.58 min, yielding a maximum HHV of 18.4853 MJ/kg. These findings demonstrate the potential of torrefaction for upgrading filter cake residue into a high-quality solid biofuel, providing a sustainable solution for waste utilization in the sugar industry.

Multi-Laser Scan Assignment and Scheduling Optimization for Large Scale Metal Additive Manufacturing

Metal additive manufacturing (AM) has attracted significant attention in various industry sectors for large-scale fabrication. However, the limited fabrication efficiency has hindered its practical implementation. In comparison to traditional methods of tuning process parameters, concurrent AM equipped with multiple independently driven lasers is a more promising technique recently developed for the efficient fabrication of large metal parts. To maximize fabrication efficiency while ensuring quality for multi-laser AM processes, an optimization problem is proposed in this work for multi-laser scanning plan, including scan vector assignment and scheduling. The goal is to minimize the makespan while considering factors that may affect the quality of metal AM parts as constraints. Specifically, the constraints associated with heat-affected zones (HAZs) and the user-specified single-laser scanning area are considered. The optimization model is solved by deep reinforcement learning (DRL), offering the flexibility to include or exclude considerations for different quality/process requirements. Two case studies demonstrate the application of DRL models considering different sets of constraints and compare their performance with two baseline scheduling methods in terms of fabrication efficiency and violation of quality constraints. In addition, the impact of the laser number on operational improvement and the computational cost of the DRL model is also studied.

Response Surface Methodology to Explore the Influence Mechanism of Fiber Diameter in a New Multi-Needle Electrospinning Spinneret

Multi-needle electrospinning is an efficient method for producing nanofiber membranes. However, fluctuations in the fluid flow rate during the process affect membrane quality and cause instability, an issue that remains unresolved. To address this, a multi-stage flow runner spinneret needs to be developed for large-scale nanofiber membrane production. This paper uses COMSOL finite element software to simulate polymer flow in the spinneret runner. From this, the velocity field distribution and velocity instability coefficient were obtained, providing theoretical guidance for optimal spinneret design. In addition, response surface analysis (RSM) was used to experimentally explore the process parameters, and then residual probability plots were used for reliability verification to evaluate the effect of each process parameter on fiber diameter. These process parameters can guide the controlled production of nanofibers during multi-needle electrospinning.

Influence of 3D printed porous aluminum anode structure on electrochemical performance

Aluminium-air (Al-air) batteries have been considered as one of the most promising next-generation energy storage devices. In this study, we investigated the effect of structural changes in the main body of porous aluminium anode on the electrochemical performance under the constraints of the 3D printing process using both simulation and experimental methods. By analysing the simulation results under the constraint of 3D printing process, we found that the variation of the base fillet radius affects the dimensional deviation of the porous aluminium anode. As the radius of the fillet increases, the degree of warpage deformation gradually decreases. For this reason, we experimentally verified the self-corrosion rate, electrochemical and discharge properties of aluminium anodes under the same process parameters. The test results are consistent with the simulation analysis. With the increase of fillet radius, the self-corrosion rate of anode gradually decreases and the electrochemical activity gradually increases. Meanwhile, the discharge voltage was as low as 1.55 V in the periphery without rounded corners, and increased by 1.3 % and 3.2 % when the periphery radius was 1 mm and 2 mm, respectively. This research result provides a new method for other researchers to further improve the overall performance of aluminium-air batteries.

Impact of Cold Atmospheric Plasma Pretreatment on the Recovery of Phenolic Antioxidants from Spent Coffee Grounds

AbstractIn the present study, cold atmospheric plasma (CAP) was employed as a pretreatment method for the extraction of phenolic compounds from spent coffee grounds (SCGs). The impact of CAP treatment conditions, i.e., thickness of the SCGs layer (mm), distance between the plasma source and the SCGs layer (mm) and duration of CAP treatment (min), on the total phenol content, in vitro antioxidant activity, as well as caffeine and chlorogenic acid content of SCGs, was investigated. The process parameters were optimized with the aid of response surface methodology (RSM). After optimizing the CAP pretreatment conditions, the CAP-treated SCGs were subjected to ultrasound-assisted extraction using ethanol as the extraction solvent. The optimum conditions for CAP treatment identified, i.e., thickness, 1 mm; distance, 16 mm; and duration, 15 min, led to a significant enhancement in the recovery of bioactive compounds from SCGs compared to those obtained from untreated SCGs. Total phenolic content and antioxidant activity significantly increased (i.e., TPC from 19.0 ± 0.7 to 24.9 ± 1.4 mg GAE/100 g dry SCGs, ADPPH from 106.7 ± 5.01 to 112.3 ± 4.3 μmol Trolox/100 g dry SCGs, AABTS from 106.7 ± 5.01 to 197.6 ± 5.8 μmol Trolox/100 g dry SCGs, ACUPRAC from 17938 ± 157 to 18299 ± 615 μmol Trolox/100 g dry SCGs). A significant increase in caffeine content from 799.1 ± 65.1 mg to 1064 ± 25 mg/100 g dry SCGs and chlorogenic acid content from 79.7 ± 15.3 mg to 111.3 ± 3.3 mg/100 g dry SCGs, was also observed. Overall, CAP pre-treatment can be used to enhance the recovery of bioactive compounds from SCGs.

Comparative study of electrogas and shielded metal arc welding processes on steel A537 welded joints

Abstract In this research, the electro-gas welding process (EGW) was compared with a shielded metal arc welding process (SMAW) from a mechanical properties point of view. Visual and radiographic inspections confirmed the soundness of weldments produced by both EGW and SMAW techniques. Various assessments, including hardness, tensile strength, V-notch impact toughness, macrostructure, microstructure, and electrochemical tests, were performed. The mechanical properties of the two welding processes were closely matched, with an average tensile strength of 590 MPa for EGW and 585 MPa for SMAW. The impact of welding variables, such as groove design and heat input, on the quality, mechanical properties, and electrochemical behavior of the welded joints was thoroughly examined. Dilution estimates, particularly for the EGW process, were around 35%, and a significant similarity was observed between the chemical composition determined through dilution calculations and that obtained from chemical analysis using an arc spark emission spectrometer. Notably, the EGW process demonstrated exceptional productivity, surpassing the SMAW process by more than 11 times. The optimal welding parameters for the EGW process were identified to achieve superior mechanical properties, low corrosion rates, and reduced consumption of the welding electrodes. This included adopting a single V type and groove angle of 300 instead of 600, resulting in a 23% reduction in economic costs. Selecting an appropriate heat input within the range of 12 to 14 kJ/mm further contributed to enhancing overall welding efficiency.

Synthesis, Optimization and Molecular Self-Assembly Behavior of Alginate-g-Oleylamine Derivatives Based on Ugi Reaction for Hydrophobic Drug Delivery

To achieve the optimal alginate-based oral formulation for delivery of hydrophobic drugs, on the basis of previous research, we further optimized the synthesis process parameters of alginate-g-oleylamine derivatives (Ugi-FOlT) and explored the effects of different degrees of substitution (DSs) on the molecular self-assembly properties of Ugi-FOlT, as well as the in vitro cytotoxicity and drug release behavior of Ugi-FOlT. The resultant Ugi-FOlT exhibited good amphiphilic properties with the critical micelle concentration (CMC) ranging from 0.043 mg/mL to 0.091 mg/mL, which decreased with the increase in the DS of Ugi-FOlT. Furthermore, Ugi-FOlT was able to self-assemble into spherical micellar aggregates in aqueous solution, whose sizes and zeta potentials with various DSs measured by dynamic light scattering (DLS) were in the range of 653 ± 25~710 ± 40 nm and −58.2 ± 1.92~−48.9 ± 2.86 mV, respectively. In addition, RAW 264.7 macrophages were used for MTT assay to evaluate the in vitro cytotoxicity of Ugi-FOlT in the range of 100~500 μg/mL, and the results indicated good cytocompatibility for Ugi-FOlT. Ugi-FOlT micellar aggregates with favorable stability also showed a certain sustained and pH-responsive release behavior for the hydrophobic drug ibuprofen (IBU). Meanwhile, it is feasible to control the drug release rate by regulating the DS of Ugi-FOlT. The influence of different DSs on the properties of Ugi-FOlT is helpful to fully understand the relationship between the micromolecular structure of Ugi-FOlT and its macroscopic properties.

Numerical Simulation Study of Wall Thickness Change Rule of Single Point Progressive Molding of Al5083

With the development and progress of science and technology, the application of single-point progressive molding is more and more extensive, but single-point progressive molding still exists the problem of excessive thinning of wall thickness of molded parts, which seriously affects the quality of molded parts. The article takes Al5083 plate forming cone as the research object, uses Abaqus finite element simulation software, according to the principle of single variable, respectively explores the influence of process parameters such as tool head diameter, layer spacing, feed rate and residual height on the average wall thickness reduction rate and the maximum wall thickness reduction rate of the molded parts. The results show that: increasing the tool head diameter, the average wall thickness reduction rate increases and the maximum wall thickness reduction rate decreases; the average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of ply spacing; the average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of the tool feed rate; the average wall thickness reduction rate decreases and the maximum wall thickness reduction rate increases with the increase of the residual height.

Multi-objective Optimization of Process Parameters for Surface Quality and Geometric Tolerances of AlSi10Mg Samples Produced by Additive Manufacturing Method Using Taguchi-Based Gray Relational Analysis

AbstractIn this study, it has been focused on examining the effects of production parameters on quality parameters such as surface roughness and geometric tolerances in the production of AlSi10Mg samples by the additive manufacturing method. The experimental design has been prepared according to the Taguchi L27 orthogonal array. As a result, in the production of samples, increasing laser power (P) contributed positively to surface roughness and diameter change, and increasing scanning distance (SD) negatively contributed to circularity change and concentricity. Further, it has been determined that increasing the scanning speed (SS) negatively affects the concentricity change of the produced samples. The optimum production parameters for surface roughness and diameter variation has been determined as A1B1C3. The optimum production parameters for circularity variation and concentricity have been determined as A3B3C1 and A3B1C1, respectively. According to the ANOVA analysis results, the most effective parameters for surface roughness, diameter change, circularity change and concentricity have been 53.22% P, 62.45% SD, 37.23% SS and 40.41% SD, respectively. Furthermore, as a result of the gray relationship analysis (GRA) performed for the output parameters, the optimum production parameter has been determined as A2B1C3.

Study on Mechanical and Electrical Properties of High Content CNTs/Cu Composites

It is expected that composites made of carbon nanotubes (CNT) and copper (Cu) display both mechanical and electrical properties, but the low damage dispersion and high-quality composite of high-content CNTs have always been research difficulties. In this paper, high-content CNTs/Cu composites were prepared. The effects of the sintering method, sintering temperature, directional rolling and the CNTs’ content on the relative density, hardness and electrical conductivity of the composites were studied. The uniform dispersion of high-content CNTs in Cu matrix was achieved by ball milling, sintering and rolling, and the processes did not cause more damage to the CNTs. The properties of composites prepared by spark plasma sintering (SPS) and vacuum hot pressing sintering (HPS) were compared, and the optimum process parameters of SPS were determined. When the CNTs’ content is 2 wt.%, the hardness is 134.9 HBW, which is still 2.3 times that of pure Cu, and the conductivity is the highest, reaching 78.4%IACS. This study provides an important reference for the high-quality preparation and performance evaluation of high-content CNTs/Cu composites.

Analysis of Operational Control Data and Development of a Predictive Model of the Content of the Target Component in Melting Products

The relevance of this research is due to the need to stabilize the composition of the melting products of copper–nickel sulfide raw materials. Statistical methods of analyzing the historical data of the real technological object and the correlation analysis of process parameters are described. Factors that exert the greatest influence on the main output parameter (the fraction of copper in a matte) and ensure the physical–chemical transformations are revealed: total charge rate, overall blast volume, oxygen content in the blast (degree of oxygen enrichment in the blowing), temperature of exhaust gases in the off-gas duct, temperature of feed in the smelting zone, copper content in the matte. An approach to the processing of real-time data for the development of a mathematical model for control of the melting process is proposed. The stages of processing of the real-time information are considered. The adequacy of the models was assessed by the value of the mean absolute error (MAE) between the calculated and experimental values.