Control Of Process Parameters Research Articles

An Overview of the Mechanical and Tribological Characteristics of Non - Ferrous Metal Matrix Composites for Advanced Engineering Applications

The ever increasing service requirement of industries like automobile, aerospace, marine, infrastructure and transportation have evolved non-ferrous metal matrix composites with different combinations of ceramic and soft reinforcements which have resulted in the improvement of their tribo-mechanical properties as compared to an unreinforced alloy. Secondary reinforcements provide safe disposal of agro-industrial waste thereby reducing environmental degradation. The scanning electron micrographs reveals fairly uniform dispersal of reinforcement in metal matrix if proper conditions are maintained and porosity levels are found to be in acceptable range. The density, hardness, wear resistance, tensile strength, fatigue strength and impact strength of non-ferrous composites have been found to be either comparable or superior to an unreinforced alloy with minimum weight and cost. The purpose of current study is to explore the nonferrous composites and propose their application area based on material properties. An attempt has been made for indepth review on the effect of controllable process parameters on tribo-mechanical properties of the non-ferrous composites. The study concludes that non- ferrous composites with single or more than one reinforcement have superior tribo-mechanical characteristics making them suitable for design of high performance, low cost and low weight to strength ratio components.

Investigation of laser micro-drilling machinability and performance optimization of polymer nanocomposites reinforced with different carbon allotropes

The comparative assessment of the laser micro-drilling machinability of polymer matrix nanocomposites dispersed with conducting fillers of different carbon allotropes (carbon nanotube (CNT), graphite, and carbon black (CB)) to produce minimum taper and heat-affected zone (HAZ) has been first time reported in this article. The required composite specimens are synthesized via ultrasonicator-assisted compression molding method and characterized for their thermal, electrical, and mechanical properties. The central composite design-based response surface methodology (CRSM) is implemented for the planification of experimentation using a pulsed Nd:YAG laser and subsequent higher-order regression modeling of the desired performance indicators. The contemporary accelerated particle swarm optimization (APSO) technique and metaheuristic whale optimization algorithm (WOA) have been utilized to define optimum controllable process parameters (pulse frequency, cutting speed, lamp current, and air pressure) and the assortment of optimum conditions are justified by performing confirmatory tests. CNT-reinforced composite material exhibits superior tensile, hardness, and thermal properties whereas graphite-based polymer composite show good electrical conductivity. The most minor taper and HAZ values are observed in the laser micro-drilling of epoxy-based CNT and CB materials, respectively. The two swarm-based algorithms predict more accurate results for the desired output responses than the statistical CRSM, with the least errors compared to the values attained by the WOA. Optimal taper (with CNT/epoxy composite at 30 m/s cutting speed, 22.6 amp lamp current, 3 kHz pulse frequency, and 1 kg/cm2 air pressure) and HAZ (with CB/epoxy composite at 30 m/s cutting speed, 22.97 amp lamp current, 3 kHz pulse frequency, and 5 kg/cm2 air pressure) values obtained in the confirmatory test showed 15% and 12% errors, respectively, as compared to the predicted data in WOA.

Optimization of key quality indicators in material extrusion 3D printing of acrylonitrile butadiene styrene: The impact of critical process control parameters on the surface roughness, dimensional accuracy, and porosity

Optimization of key quality indicators in material extrusion 3D printing of acrylonitrile butadiene styrene: The impact of critical process control parameters on the surface roughness, dimensional accuracy, and porosity

Bi2Te3 Thin Films Deposited by the Combination of Bi and Te Plasmas in a PLD Process

Bismuth telluride thin films were grown by pulsed laser deposition by implementing a novel method that combines both Te and Bi plasmas resulting from the laser ablation of individual Bi and Te targets. Furthermore, the mean kinetic ion energy and density of the plasmas, as estimated by TOF curves obtained from Langmuir probe measurements, were used as control parameters for the deposition process. The obtained thin films exhibit a metallic mirror-like appearance and present good adhesion to the substrate. Morphology of the thin films was observed by SEM, yielding smooth surfaces where particulates were also observed (splashing). Chemical composition analysis obtained by EDS showed that apparently the films have a Te-rich composition (ratio of Te/Bi of 3); however, Te excess arises from the splashing as revealed by the structural characterization (XRD and Raman spectroscopy). The XRD pattern indicated that depositions have the rhombohedral (D3d5 (R3¯m)) structure of Bi2Te3. Likewise, Raman spectra exhibited the presence of signals that correspond to Eg2, A1u2 and A1g2(LO) vibrational modes of the same rhombohedral phase of Bi2Te3. Additionally, oxidation states, analyzed by XPS, resulted in signals associated to Bi3+ and Te2- that correspond to the Bi2Te3 compound. Finally, surface topology and thickness profiles were obtained from AFM measurements, confirming a combination of a smooth surface with particulates on top of it and a film thickness of 400 nm.

Effect of cavity shape on microstructural evolution of pure aluminum in electrically-assisted solidification

Grain refinement is a crucial issue in metallic materials. One of the emerging techniques to obtain equiaxed grains is to apply an electric current to the liquid metal during solidification. With this view, in this paper, the effect of electric current on the solidification behavior in various cavity shapes of mold was investigated. Cylinder-, cube-, and cuboid-shaped cavities designed to have similar cavity volume were used. By applying an electric current during the solidification of liquid aluminum, the grains were effectively refined with a grain size of approximately 350 µm for all three types of cavities. The circulating flow of liquid aluminum was observed to have a similar shear rate intensity in all three types of cavities, which is known to be sufficiently high (over hundreds of s−1) to induce dendrite fragmentation resulting newly generated nuclei. Dispersion of nuclei on unsolidified aluminum appeared differently according to the shape of the cavity, which influences final shape of refined zone. The area fraction of refined zone was affected by the relative relationship between the solidification completion time and the electric current application time. This study will provide insight to control of process parameters when electrically-assisted solidification is applied to a real product with a complex shape.

Functionality Versus Sustainability for PLA in MEX 3D Printing: The Impact of Generic Process Control Factors on Flexural Response and Energy Efficiency

Process sustainability vs. mechanical strength is a strong market-driven claim in Material Extrusion (MEX) Additive Manufacturing (AM). Especially for the most popular polymer, Polylactic Acid (PLA), the concurrent achievement of these opposing goals may become a puzzle, especially since MEX 3D-printing offers a variety of process parameters. Herein, multi-objective optimization of material deployment, 3D printing flexural response, and energy consumption in MEX AM with PLA is introduced. To evaluate the impact of the most important generic and device-independent control parameters on these responses, the Robust Design theory was employed. Raster Deposition Angle (RDA), Layer Thickness (LT), Infill Density (ID), Nozzle Temperature (NT), Bed Temperature (BT), and Printing Speed (PS) were selected to compile a five-level orthogonal array. A total of 25 experimental runs with five specimen replicas each accumulated 135 experiments. Analysis of variances and reduced quadratic regression models (RQRM) were used to decompose the impact of each parameter on the responses. The ID, RDA, and LT were ranked first in impact on printing time, material weight, flexural strength, and energy consumption, respectively. The RQRM predictive models were experimentally validated and hold significant technological merit, for the proper adjustment of process control parameters per the MEX 3D-printing case.

Separation and identification of degradation impurities of esomeprazole sodium.

Drug impurities are important factors that affect drug safety and efficacy. The aim of this study is to separate and confirm the structure of two degradation impurities of esomeprazole sodium, designated X and Y. The impurities X and Y were successfully isolated using preparative HPLC by developing separation methods with the help of ACD/Labs AutoChrom software. There was a steady increase in X and Y impurities in forced esomeprazole sodium degradation. Impurity X was confirmed as 6-methoxy-1h-benzo[d]imidazole-2-yl-4-amino-3,5-dimethylpyridinecarboxylate and impurity Y as 6-methoxy-1h-benzo[d]imidazole-2-yl-4-hydroxy-3,5-dimethylpyridinecarboxylate using nuclear magnetic resonance spectrometry, infrared spectroscopy, and high-resolution mass spectrometry. These findings provide a comprehensive understanding of the impurity profile of esomeprazole sodium because these impurities are reported for the first time. Based on our results, active pharmaceutical ingredient manufacturers can further control process parameters to reduce impurity generation, and drug production manufacturers can optimize the packaging and storage conditions of esomeprazole sodium.

Impact of Primary Air Separation in a Grate Furnace on the Resulting Combustion Products

When burning fuel in grate furnaces, supplying the right amount of air to them is as important as the method of air supply. In a furnace with a fixed grate, the supply method of primary air is determined by the distribution of the supplied air stream over time, and in a furnace with a movable grate, the said method involves the distribution of the stream along the active length of the grate. The need to account for air distribution is attributable to complex processes that occur during the combustion process. The paper describes experimental studies aimed at determining the influence of the distribution of the supplied primary air on the emission of CO2, CO, SO2, NOx, and on the content of combustible parts in the slag. In all cases, the total amount of primary air supplied to the process as well as other process control parameters was identical, and only the distribution of primary air was different. The paper proposes the use of a generalized function to describe the distribution of air, defined by its total demand and the relative time R that fuel remains on the grate until the maximum air stream is obtained. The quantity R was accepted at the value ranging from 1/6 to 2/3. With the rise of R, the emissions of CO2, CO, and SO2 increased by 53%, 125%, and 27%, respectively, and the emissions of NOx and the share of combustibles in the slag decreased by 12% and 79%, respectively.

Recombinant Peptide Production Softens Escherichia coli Cells and Increases Their Size during C-Limited Fed-Batch Cultivation.

Stress-associated changes in the mechanical properties at the single-cell level of Escherichia coli (E. coli) cultures in bioreactors are still poorly investigated. In our study, we compared peptide-producing and non-producing BL21(DE3) cells in a fed-batch cultivation with tightly controlled process parameters. The cell growth, peptide content, and cell lysis were analysed, and changes in the mechanical properties were investigated using atomic force microscopy. Recombinant-tagged somatostatin-28 was expressed as soluble up to 197 ± 11 mg g-1. The length of both cultivated strains increased throughout the cultivation by up to 17.6%, with nearly constant diameters. The peptide-producing cells were significantly softer than the non-producers throughout the cultivation, and respective Young's moduli decreased by up to 57% over time. A minimum Young's modulus of 1.6 MPa was observed after 23 h of the fed-batch. Furthermore, an analysis of the viscoelastic properties revealed that peptide-producing BL21(DE3) appeared more fluid-like and softer than the non-producing reference. For the first time, we provide evidence that the physical properties (i.e., the mechanical properties) on the single-cell level are significantly influenced by the metabolic burden imposed by the recombinant peptide expression and C-limitation in bioreactors.

Responses of microbial community to geochemical parameters on vertical depth in bioheap system of low-grade copper sulfide

Monitoring of the microbial community in bioleaching system is essential for control process parameters and enhance the leaching efficiency. Due to the difficulty of sampling, microbial distribution, community succession and bioleaching activity along the vertical depth of bioleaching heaps remain unresolved. This study investigated the geochemical parameters and microbial community structure along a depth profile in a bioleaching heap and leachate. 80 ore samples at different heap depths and 9 leaching solution samples from three bioheaps of Zijin Copper Mine were collected. Microbial composition, mineral types and geochemical parameters of these samples were analyzed by 16S rRNA high-throughput sequencing and a series of chemical measurement technologies. The results revealed that the pH, Cu, Fe and the total sulfur contents were the major factors shaping the composition of the microbial communities in the bioleaching system. The extent of mineral oxidation increased as the sample depth increases, followed by the increasing of sulfur oxidizers. The abundance of sulfur and iron oxidizers including members of Acidithiobacillus, Sulfobacillus and Acidiferrobacter were significantly higher in the leaching heap than in the leaching solution, meanwhile, they showed strong positive interactions with other members within the same genera and iron oxidizer Leptospirillum and Ferroplasma. Besides, Acidithiobacillus negatively interacted with heterotrophs such as Sphingobium, Exiguobacterium, Brevundimonas and so on. On the contrast, members of Leptospirillum and unclassified Archaea were significantly abundant in the leaching solution and revealed strong interactions with members of Thermoplasmatales. The main conclusion of this study, especially the leaching potential of microorganisms prevailing in bioheaps and their relationships with geochemical factors, provides theoretical guidance for future process design such as the control of processing parameters and microbial community in heap leaching.

Adaptive optimal process control with actor-critic design for energy-efficient batch machining subject to time-varying tool wear

Batch machining systems are essential for improving productivity and quality, but they consume considerable amounts of energy due to the continuous interaction with machine tools, workpieces, and cutting tools. In contrast to single-piece machining that has a short production cycle, the tool wear impacts in batch machining systems on energy consumption cannot be underestimated. However, few studies have focused on adaptive process control subject to time-varying tool wear because process optimization has always been previously considered a static problem. As an alternative to metaheuristic algorithms, reinforcement learning (RL) offers an attractive means for solving such a dynamic, high-dimensional, and high-coupling problem. In the case of turning cylindrical parts, an energy-efficient decision model is developed for the process control of pass operations of batch machining. The decision variables are decoupled by reformulating the problem as the Markov decision process, wherein the tool wear experiences dynamic changes. To solve the problem, an actor-critic RL framework with multi-constraint and multi-objective design is developed. Based on the framework, a dynamic process control method is proposed where the RL agent observes workpiece features, machining requirements, and tool wear states (inputs) and adaptively selects the control parameters such as cutting speed, feed rate, and cutting rate (outputs), with the aim to conserve energy. Two application tests and comparisons against metaheuristic methods are performed. The results indicate that the method can further reduce energy by over 20% compared with energy-efficient optimization ignoring tool wear effects. The learning efficiency of RL is about three times faster than that of metaheuristics. The online sampling time is less than 0.1 millisecond, which facilitates real-time control of process parameters.

Experimental Investigation of the Porous Free Zone of Silicon Cemented Layer Obtained through Pack Cementation

The development of a porous free zone of the silicon cemented layer represents a scientific and technical challenge. The limitation of the effects of the Kirkendall–Frenkel phenomena requires the right control of the thermochemical processing parameters (temperature, time, and chemical) and thorough knowledge of the related interaction with the specific elements of the metallic matrix of the thermochemically processed product. Through the experimental programming method, the individual and cumulated effects of the thermochemical processing parameters on (Fe-Armco) high-purity iron cemented by silicon in ferrosilicon (FeSi75C) powdered solid media have been quantified. It was concluded that ferrosilicon with silicon concentrations higher than 60% (FeSi75C) represents a redoubtable active component, especially in a temperature range higher than 1100 °C. In the layer cemented with silicon, the presence of nitrogen was also observed, as a direct consequence of the composition of the medium used for cementation. The presence of this element is the predominant result of the manifestation of the ionic phenomenon of adsorption. The correlations between these parameters and the dimension of the porous free zone of the silicon cemented layer in the vicinity of the thermochemically processed surface have been determined.

Impurity Purging through Systematic Process Development of a Continuous Two-Stage Crystallization

A methodical development approach was deployed in a novel portable manufacturing (Pharmacy on Demand) unit to purify ciprofloxacin hydrochloride hydrate within assay, water content, and impurity specifications described by the United States Pharmacopeia (USP) monograph and ICH Q3A(R2) guidelines for new impurities in drug substances. A series of design-of-experiment (DOE) and one-factor at a time (OFAT) experiments led to the optimization and control of a continuous two-stage crystallization that increased both the purity and yield of ciprofloxacin hydrochloride hydrate. Additionally, a statistically significant linear model was derived in batch within a 20 °C range that tracked the level of a difficult-to-purge impurity in stage 1 of the purification. This model was tested in continuous flow and predicted the impurity removal within 5% accuracy. With parametric control of process parameters, determined by optimization and modeling work, continuous flow isolations produced an active pharmaceutical ingredient (API) which had no individual impurities above 0.07%, with an isolated yield of 74%. In addition, acceptance criteria for assay (between 98 and 102%) and water content (between 4.7 and 6.7%) were met per the USP monograph for ciprofloxacin hydrochloride hydrate for the first time in the novel POD system.

A critical review on effect of nanoparticles and process parameters on metallurgical properties of friction stir processing of dissimilar aluminum alloys

Friction stir welding (FSW) and friction stir processing (FSP) are unique solid-state joining and surface modification techniques that offer several advantages over conventional fusion welding and surface treatment methods. The ability to modify the microstructure and properties of the weld and surface through the control of processing parameters is a key advantage of FSW/FSP. This has led to a great deal of research on understanding the microstructural evolution during FSW/FSP. One important aspect of microstructural control in FSW/P is the development of grain structures and textures. The high strain rates and temperatures during FSW/P can lead to dynamic recrystallization and the formation of refined and homogeneous grain structures. The degree of grain refinement and texture development can be controlled through the selection of processing parameters such as tool geometry, rotation speed, traverse speed, and applied pressure. Another important aspect of microstructural control in FSW/P is the formation of phases, phase transformations, and precipitation. The ability to control grain structures, phases, and IMCs, as well as the potential for local refinement and the formation of MMCs, makes FSW/P an attractive option for a wide range of applications. Continued research and development will be critical for further advancing the capabilities and potential of FSW/P.

Implementation of quality management by controlling process parameters in spheroidisation

This article discusses the Quality Management (QM) implementation at South Africa’s Nuclear Energy Cooperation (Necsa) for the reconditioning of Ti6Al4V. The reconditioning serves to spheroidise Ti6Al4V from selective laser melting. The quality management tool was implemented to ensure the consistent output of the spheroidised Ti6Al4V. Steps taken to spheroidise Ti6Al4V were documented, and the tools and resources required to ensure the process flows smoothly were highlighted. Standard operating procedures were developed to provide a guide for operators of the spheroidisation facility on the operating parameters needed to consistently spheroidise Ti6Al4V. The main process parameter investigated was the relationship between power and spheroidisation and vaporisation. There are two types of process parameters for effective reconditioning of Ti6Al4V. There are the parameters that operate with the aim of ensuring consistent quality, and the second set ensures economic reconditioning of Ti6Al4V. QM would also ensure that there are standard operating procedures developed within an organisation. For the research, the operating parameters to economically spheroidise Ti6Al4V were determined-

Performance improvement of the Savonius turbine using a novel augmentation device with the Taguchi optimization method

This paper proposes a new augmentation device to improve the coefficient of power (Cp) of a Savonius turbine using a computational fluid dynamics method. The device is a rotating cylinder synchronized with a rotating turbine using a timing belt mechanism without needing any external power source. Unlike conventional flow deflectors, the device is not placed in front of the turbine. Instead, it is placed parallel to the turbine position. The optimum device diameter and position are determined using the Taguchi optimization method. The device diameter and its position (lateral distance, longitudinal distance, and location; left and right) are selected as controllable process parameters and the Cp as the performance output. The Taguchi L16 orthogonal array is selected as the design of experiment. From the Taguchi analysis, the optimum device parameter improves the Cp by up to 0.3877 at a tip speed ratio (TSR) of 0.9, a 55.64% improvement relative to the case without the device. The highest Cp achieved is 0.4450 at TSR 1.1 with an 83.73% improvement relative to the case without the device. Analysis of variance results suggest that the Cp is greatly influenced by both the device diameter and lateral distance. The proposed device improves the overall performance of the Savonius turbine over a wide range of TSR.

Структура и свойства слоистых композитов WC–Cu, полученных в условиях вибрации

One of the most popular and widely used is the WC – Co composite. To improve some functional properties: thermal conductivity, corrosion resistance, etc., a search is underway for alternative metal binders with the possible replacement of Co with copper to reduce sintering temperatures and provide a higher thermal conductivity of the composite. Previously, it was shown that melt impregnation of freely poured refractory powders into a crucible-mould, activated by low-frequency vibration (LFV) of their compositions, differs from the methods used in industry in the simplicity of technology, short duration, and the possibility of obtaining composites with a high content of refractory phase with its frameless packaging. 2 – 3-layer WC – Cu/Cu and Cu/WC – Cu/Cu composites with different arrangement of the working WC – Cu layer along the height of the ingot and different structural characteristics and properties of the layer have been obtained. The influence of thermal and temporal conditions, pressure of cold prepressing of WC powder, dilution of carbide powder with copper powder, geometry of stacking of alloy components on the formation of a given lamination of a composite alloy, a given composition, and a minimum porosity of the WC – Cu working layer are analyzed. The hardness and wear resistance of the WC – Cu layer were measured and their relationship with the layer structure and controlled parameters of the composite synthesis process control was established. Both the porosity of the structure and the presence of dense macroaccumulations of WC in the Cu-matrix can be reduced to a minimum by preventive small pre-pressing of freely poured powders at room temperature before loading the alloy components into the furnace, followed by processing of the vibration. Composites with a homogeneous structure and low porosity of the working layer have been obtained.

Comparison of different supervised machine learning algorithms for bead geometry prediction in GMAW process

Gas Metal Arc Welding (GMAW) is an extensively implemented arc welding process through the control of input process parameters and the metal from the filler wire. Despite its popular use in various industries, the complex interrelationship between the actual bead and the varying welding parameters makes it challenging to predict appropriate bead geometries via mathematical modeling in a continually changing welding process. In this study, the Regression Learner App was used to compare the performance of supervised Machine Learning (ML) predictive models comprising the Linear Regression (LR), Regression Tree (RT), Support Vector Machine (SVM), Ensembles of Tree (ET), Gaussian Process Regression (GPR), and Artificial Neural Network (ANN) using GMAW dataset. The dataset was scaled and normalized at a range of -1 to +1 to facilitate the visualization of the variation effect. The wire feed speed, voltage, weld velocity, unmelted wire length, and melted wire volume were considered as the input parameters to predict the bead geometry. In addition, the five-fold cross-validation was employed to avoid overfitting and poor generalization. Finally, statistical indicators, namely the Coefficient of Determination (R2), Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE), were performed on all developed models to evaluate their performance. Thus, the fine tree and ANN models achieved the highest prediction accuracies of 88–91%, signifying their potential use in future research. In short, the present study demonstrated the performance of various supervised ML algorithms for bead geometry prediction, which would assist the selection of appropriately supervised ML algorithms in future studies.

Research on Real-Time Data Transmission and Feature Analysis Technology of Smart Tool Holder

Cutting force, vibration, and cutting temperature are the significant characteristics of the cutting process for real-time monitoring and optimization. Smart tool holder technology is one of the key technologies to effectively monitor the cutting process. In order to realize real-time monitoring of the cutting process, a data transmission and processing technology based on the smart tool holder is proposed. First, a data transmission scheme based on socket communication technology is developed. Then, a data transmission format based on Modbus protocol and BCD code is proposed. Finally, the feature analysis technology of real-time data is discussed for the requirements of real-time control and optimization of process parameters. The proposed technology is conducive to improving the data processing efficiency of the data transmission process of the smart tool holder and is of great significance to the standardization of data transmission based on the smart tool holder.

Use of information technology for traceability and quality control: Case study in a Brazilian winery

Food safety and quality are current demands from consumers and markets, which ends up being reflected in the wine sector and throughout its chain. However, they can pose operational challenges, especially for small or medium-sized wineries. This study aims to develop the traceability of the grape used in wine production supported by information technology in a winery situated in Garibaldi, RS, Brazil. The study was carried out in three phases: protocol development, implementation of an information system and evaluation of the results, identifying opportunities and barriers. A standard protocol for the grapes traceability was developed, considering data from grape cultivation, delivered grape quality assessment and grape processing control parameters until bottling. Demetra software was deployed, developed by Elysios. The implementation of traceability and the information system will be a step towards obtaining international certifications. The study contributes to bringing international standards of food safety and quality to the Brazilian context. In this sense, the study contributes to expanding the applied knowledge on the field and to support professionals and wineries in the development of strategies for the implementation of traceability systems.