Vital Process Parameters Research Articles

Effect of mechanochemical activation parameters on vanadium recovery from vanadium-bearing steel slag: Critical speed derivation for wet-ball milling

The existing equations in the literature for a mechanochemical activation (MA) critical speed proved that only the ball size, volumetric filling ratio, and the vial/bowl diameter influence the milling speed, thus these equations do not account for all other crucial parameters and the critical speed is constant for all the mechanochemical process parameters for every ball size, quantity powder and number of balls considered. Milling speed is one of the vital process parameters, thus this present work derived a novel equation that accounts for the influence of ball size, the ball-to-powder/slurry weight ratio (BPR/BSR), the mass of the mineral powder, the chemical solution, the inner diameter of the vail and the liquid-to-solid ratio (L:S). MA is very beneficial to the hydrometallurgical process and these parameters are key for an enhanced recovery of the desired metals from the mineral in question. The powder and the chemical solution are related by the liquid-to-solid ratio considered in the activation process, thus as the BPR increases for the ball sizes considered, the critical speed increases drastically. Also, the effect of ball size, milling time, and speed on the recovery efficiency of vanadium from vanadium-bearing steel slag (VBSS) was investigated. The VBSS powder was Na2CO3(aq)-milled with balls of varying size at different milling speeds and ignition/milling times. A mechanochemical activation leaching experiment was carried out for 10g VBSS; at a milling speed of 140 rpm, BPR 7.8/BSR 1.02, ball diameter 10 mm, L:S ratio 5:1, temperature 90 °C, and 30-min ignition time, the vanadium recovery efficiency of above 80 % was achieved. For every predetermined mass of VBSS powder and L:S ratio of the chemical solution concentration; the BPR/BSR and the size of the ball determine the critical speeds which in turn influence the leachability of the vanadium.

Hierarchical time-series analysis of dynamic bioprocess systems.

Monoclonal antibodies (mAbs) are leading types of 'blockbuster' biotherapeutics worldwide; they have been successfully used to treat various cancers and chronic inflammatory and autoimmune diseases. Biotherapeutics process development and manufacturing are complicated due to lack of understanding the factors that impact cell productivity and product quality attributes. Understanding complex interactions between cells, media, and process parameters on the molecular level is essential to bring biomanufacturing to the next level. This can be achieved by analyzing cell culture metabolic levels connected to vital process parameters like viable cell density (VCD). However, VCD and metabolic profiles are dynamic parameters and inherently correlated with time, leading to a significant correlation without actual causality. Many time-series methods deal with such issues. However, with metabolic profiling, the number of measured variables vastly exceeds the number of experiments, making most of existing methods ill-suited and hard to interpret. Here we propose an alternative workflow using hierarchical dimension reduction to visualize and interpret the relation between evolution of metabolic profiles and dynamic process parameters. The first step of proposed method is focused on finding predictive relation between metabolic profiles and process parameter at all time points using OPLS regression. For each time point, the p(corr) obtained from OPLS model is considered as a differential metabogram and is further assessed using principal components analysis (PCA). Compared to traditional batch modeling, applying proposed methodology on metabolic data from Chinese Hamster Ovary (CHO) antibody production characterized the dynamic relation between metabolic profiles and critical process parameters.

Performance Evaluation of GAA Nanosheet FET with Varied Geometrical and Process Parameters

Nanosheet Field Effect Transistor (NSFET) is a viable contender for future scaling in sub-7-nm technology. This paper provides insights into the variations of DC FOMs for different geometrical configurations of the NSFET. In this script, the DC performance of 3D GAA NSFET is analyzed by varying the device's width and thickness. Moreover, the gate length is scaled from 20 nm to 5 nm to check for the device suitability for continuous scaling in logic applications. The thickness and width of each nanosheet are varied in the range of 5 to 9 nm and 10 to 50 nm, respectively, to analyze the performance dependency on the geometry of the device. The impact of geometry of NSFET on various DC performance metrics like transfer characteristics, sub-threshold swing (SS), on current (ION), off current (IOFF), switching ratio (ION/IOFF), threshold voltage (Vth), and drain induced barrier lowering (DIBL) are studied. On top of that, the device's electrical characteristics are analyzed for a wide range of temperatures from -43oC to 127oC to identify the temperature compensation point and is observed at VGS = 0.55 V and ID = 3.86 × 10-6 A. Furthermore, the vital process parameter, work function variations on transfer characteristics of the device is analyzed. Moreover, the analyses reveal that, for sub -7 nm, the NSFET is a potential device for high performance and suitable for logic applications.

An accurate and real-time melt pool dimension measurement method for laser direct metal deposition

Laser direct metal deposition (LDMD), as a type of additive manufacturing (AM) technology, has gained broad applications across many industries. However, producing high-quality and accurate geometric workpieces remains a challenge without controlling the fabrication process. A visual-based process monitoring system provides information about melt pool dimensions as vital process parameters for controlling the LDMD process. As the result, the accuracy of the measurement determines the performance of the control system. This paper proposes a method that includes an efficient approach for obtaining the melt pool dimensions in real time and a novel melt pool boundary calibration for finding a suitable threshold to achieve high measurement accuracy. The proposed method is verified on an LDMD system, and the experimental results show that the proposed approach has provided accurate measurements of the melt pool widths that can be used for process quality control.

An Exploratory Investigation and Optimization of Taper Cutting Operation with Wire Electro Discharge Machining

Taper cutting, a typical application of Wire Electro Discharge Machining process is widely used to produce parts with complex geometry such as cutting and extrusion dies, which finds wide application in tool and die making industry. Taper angle becomes a vital process parameter during taper cutting and is a critical performance measure for the tool and die making industry. The present investigation is initiated with a thought to optimize the different process parameters such as pulse on time (Ton), wire tension (WT), wire feed rate (WFR), taper angle (TA) on the performance measures namely taper error (TE), material removal rate (MRR) and surface roughness (SR) during taper cutting operation utilizing WEDM. Experiments were conducted using Taguchi’s L9 (34) orthogonal array on En-31 tool steel work material using brass wire of 0.25 mm diameter, as electrode material. The parametric multi-objective optimization of the experimental results has been carried out using Taguchi based Grey Relational Analysis (TGRA). The analyzed results uncovers that the pulse on time is the utmost prompting factor for MRR and SR while the taper angle cut on the work material turn out to be a significant factor for taper error.

Design, Analysis, and Test of a Novel Self-Sensing Fast Tool Servo

Fast tool servo (FTS) is playing an important role in ultraprecision machining, which however suffers the drawback that the tool/workpiece interaction force as a vital process parameter cannot be monitored. In this article, a novel self-sensing fast tool servo (SFTS) capable of simultaneous control of tool position and measurement of thrust force is developed. The SFTS is especially devised by adopting a novel dual feedback configuration to achieve the decoupled sensing of thrust force, whereas assuring the independent tool moving in feed direction. Analytical model and finite-element model are established to demonstrate the effectiveness of designed SFTS. Apart from the extended capability of traditional FTS in force sensing, theoretical analysis also reveals the proposed SFTS possesses a broad working bandwidth. Experimental verifications are carried out, and the results confirm that the SFTS exhibits nanoscale positioning accuracy, kilohertz-level working bandwidth, and meanwhile millinewton-level force sensing performance. The enabled self-sensing ability and superior performances make this unique SFTS promising and practical for broad applications in ultraprecision machining.

Nanostructured lipidic carriers of lopinavir for effective management of HIV-associated neurocognitive disorder

The current research work entails the formulation, optimization and evaluation of nanolipidic carriers of an antiretroviral drug, lopinavir for brain targeting to reduce HIV associated neurocognitive disorder. Quality by Design framework was applied for the development of nanoformulations. Solubility evaluation of the drug in various solid and liquid lipids yielded suitability of Compritol 888 and Maisine 35–1. Factor screening study was performed using Plackett-Burman design for identifying vital product and process parameters influencing the critical quality attributes of nanocarriers. Factor optimization study was carried out using Box-Behnken design, thus evaluating the NLCs for particle size, zeta potential, entrapment efficiency and in vitro drug release characteristics. The optimized nanostructured lipidic carriers were evaluated on Caco-2 cells and macrophages indicated significant improvement in the cytotoxicity and uptake performance. In vivo pharmacokinetic evaluation in rats indicated 4.8-fold and 16.5-fold increase in peak plasma concentration and area under curve from lopinavir nanostructured lipidic carriers vis-à-vis plain lopinavir, along with 2.8-fold improvement in the brain biodistribution potential. The above studies corroborated remarkable potential of the nanostructured lipidic carriers as novel drug carriers to reduce virus load in brain as major sanctuary site, thus ameliorating the neurocognitive functions.

Optimization of the Process Parameters on the Mechanical and Wear Properties of Al-SiC Nano-Composites Fabricated by Friction Stir Processing Using Desirability Approach

Aluminium silicon carbide (Al-SiC) nano composites find its application in gas turbine exit vane, structural parts of automobile and other structural applications. In the present investigation, optimization of the process parameters on mechanical and wear properties of aluminium SiC nanocomposites fabricated via friction stir processing (FSP) was studied. Three process parameters such as number of passes (A), rotational speed(B) and transverse feed(C) were used. For three factors and three levels, L9 Taguchi method was used to formulate the experimental design. Desirability approach is used to optimize the process parameters in terms of tensile strength, microhardness and wear loss. It is observed that the number of passes is the vital process parameter for tensile strength whereas rotational speed is the vital process parameter for microhardness. For three number of passes, 1500 rpm of rotational speed and 70 mm/min of transverse feed results in optimal process parameter combination for obtaining better values for tensile strength, microhardness and wear loss i.e. A3 B3 C3. The microstructure evaluation for fabricated and worn surfaces was studied using Scanning Electron Microscope (SEM).

New insights into methane hydrate dissociation: Utilization of molecular dynamics strategy

Hydrate reserves play a crucial role in energy storage and resources across the world. Gas hydrate formation may lead to various forms of blockages in oil/gas production and transportation processes, resulting in high capital and operating costs. Hence, it is important to determine the methane hydrate formation conditions and to understand the vital process and thermodynamic parameters. In this study, molecular dynamic (MD) simulations are conducted to investigate the microscopic mechanisms/phenomena and intermolecular forces involved in methane hydrate decomposition, where molecular interactions, structures, and behaviours need to be appropriately determined/selected. Through a systematic parametric sensitivity analysis, the impacts of temperature, pressure, and cage occupancy on hydrate dissociation are studied. Furthermore, the diffusion coefficient, density, and heat capacity of the methane hydrates are determined by employing MD strategy. The stability of water cages is examined at various decomposition times, temperatures, and pressures. According to the radial distribution function and mean square displacement of oxygen-oxygen and carbon-carbon atoms, the stability of hydrate cages decreases with increasing temperature, while it increases with increasing the cage occupancy and pressure. The addition of inhibitors (e.g., methanol) to small cavities in the hydrate structure creates new hydrogen bonds between the water and inhibitor molecules in the cages, accelerating the decomposition of hydrates. A good agreement is noticed between the outcomes of this research work and the results obtained in experimental and theoretical studies available in the literature. Analysing the outcome of the present and previous research works, the current study provides new reliable/logical information on the molecular level of the hydrate dissociation process. It is expected that such a research investigation offers effective tips/guidelines to deal with hydrate formation and dissociation in terms of utilization, prevention, and processing.

Optimization of parameters for micro friction stir welding of aluminum 5052 using Taguchi technique

The study investigates the effect of basic parameters in friction stir welding of thin sheet. Using Aluminum Al 5052 as the base material and Taguchi L9 orthogonal array for optimization, three vital process parameters namely rotational speed, probe shape, and transverse speed were studied with the aim to maximize the tensile strength. Alongside the process, the effect on micro hardness and grain structure of the material was also investigated and metallographic properties were studied using Scanning Electron Microscopy (SEM). Fixtures made from Bakelite and mild steel were used in the process. Experiments performed on Bakelite fixture produced defective joint for all tool shapes. The results designate square-shaped tool as the one producing sound, defect-free, and high-strength joints. Hardness increases with increase in rotational speed and decreases with increase in transverse speed. Optimal parameters found were transverse speed 200 mm/min, rotational speed 3250 rpm, and square shaped tool.

Mathematical modelling to predict mechanical properties of Copper (C101) feedstock in continuous extrusion

The continuous extrusion process is a process for producing endless profiles with a high degree of accuracy. The two important and vital process parameters are extrusion wheel velocity and product diameter which affect the mechanical and metallurgical properties of the material. In this work, continuous extrusion of pure copper (C101) rod has been carried out on commercial setup TBJ 350 for feedstock diameter of 9.5 mm at different extrusion wheel velocities and product diameters using different die sizes. The yield strength and percent elongation of extruded feedstock at different wheel velocities and product diameters has been estimated by carrying out the tensile test. The continuous extrusion process has been carried out based on two factor three-level central composite rotatable design using response surface methodology. A mathematical model has been developed to predict the mechanical properties of the extruded feedstock through continuous extrusion process and its validation has been carried out using ANOVA technique.

Microwave-Assisted Preparation of Activated Carbon from Eupatorium Adenophorum: Effects of Preparation Parameters

AbstractEupatorium adenophorum, global exotic weeds, was utilized as feedstock for preparation of activated carbon (AC) via microwave-induced KOH activation. Influences of the three vital process parameters – microwave power, activation time and impregnation ratio (IR) – have been assessed on the adsorption capacity and yield of AC. The process parameters were optimized utilizing the Design Expert software and were identified to be a microwave power of 700 W, an activation time of 15 min and an IR of 4, with the resultant iodine adsorption number and yield being 2,621 mg/g and 28.25 %, respectively. The key parameters that characterize the AC such as the brunauer emmett teller (BET) surface area, total pore volume and average pore diameter were estimated to be 3,918 m2/g, 2,383 ml/g and 2.43 nm, respectively, under the optimized process conditions. The surface characteristics of AC were characterized by Fourier transform infrared spectroscopy, scanning electron microscope and Transmission electron microscope.

Machine Control System of Steady State Superconducting Tokamak-1

Central Control System (CCS) of the Steady State Superconducting Tokamak-1 (SST-1) controls and monitors around 25 plant and experiment subsystems of SST-1 located remotely from the Central-Control room. Machine Control System (MCS) is a supervisory system that sits on the top of the CCS hierarchy and implements the CCS state diagram. MCS ensures the software interlock between the SST-1 subsystems with the CCS, any subsystem communication failure or its local error does not prohibit the execution of the MCS and in-turn the CCS operation. MCS also periodically monitors the subsystem’s status and their vital process parameters throughout the campaign. It also provides the platform for the Central Control operator to visualize and exchange remotely the operational and experimental configuration parameters with the sub-systems. MCS remains operational 24×7 from the commencement to the termination of the SST-1 campaign. The developed MCS has performed robustly and flawlessly during all the last campaigns of SST-1 carried out so far. This paper will describe various aspects of the development of MCS.

Distributable Modular Software Framework for Manufacturing Systems

Modern production processes have a high demand on reliability, automation and accuracy in order to avoid defects during the manufacturing process. Each production differs in its demands, with which can be dealt by using intelligent decision making software. In current production systems for each evaluation of a vital process parameter a different software system is used.A modular software framework was developed which can be easily adapted to different production processes and different sensor inputs. It also supports an easy nearly “plug&play” integration of new processing algorithms. Thus making it possible to deal with multiple evaluation within one process and throughout different machines and processes using one common software framework architecture.The software consists of different basic modules connected via the framework and a common data structure. The modules can be customized using a simple configuration file.The framework connects the main modules data acquisition, data preparation, processing algorithms, decision making, a database and the controller integration. All of the modules are optional and can be adjusted with the configuration file.By using a common data structure and communication protocol it is also possible to distribute the modules over different PCs and machines as long as they are connected by a network.This features are creating a software framework able to be adapted easily to different use cases within one production process and also different production processes.This software was successfully integrated into production environments within a European project realizing an in-process real time control of the machine to minimize defects.

Multivariate optimization of process parameters in the synthesis of calcined Ca‒Al (NO3) LDH for defluoridation using 33 factorial, central composite and Box–Behnken design

ABSTRACTResponse surface methodology was applied for the first time in the optimization of the preparation of layered double hydroxide (LDH) for defluoridation. The influence of three vital process parameters (viz. pH, molar ratio and calcination temperature) in the synthesis of the adsorbent ‘Calcined Ca‒Al (NO3) LDH’ was thoroughly examined to maximize its fluoride scavenging potential. The process parameters were optimized using the 33 factorial, face centered central composite and Box–Behnken designs and a comparative assessment of the methods was conducted. The maximum fluoride removal efficiency was achieved at a calcination temperature of approximately 500ºC; however, the efficiency decreased with increasing pH and molar ratio. The outcome of the comparative assessment clearly delineates the case specific nature of the models. A better predictability over the entire experimental domain was obtained with the 33 factorial method, whereas the Box–Behnken design was found to be the most efficient model with lesser number of experimental runs. The desirability function technique was performed for optimizing the response, wherein face centered central composite design exhibited a maximum desirability. The calcined Ca‒Al (NO3) LDH, synthesized under the optimum conditions, demonstrated the removal efficiencies of 95% and 99% for the doses of 3 g L−1 and 5 g L−1, respectively.

Thermo-Chemical Hydrogen Production Technology from Biomass

As one of the few long-term sustainable clean energy carriers, hydrogen (H2) has attracted a great deal of attention. It has been projected as the most promising source of energy with less pollution on environment, especially without CO2 emission. Biomass as a neutral carbon source is considered as an ideal primary energy source, which can be expected to gradually replace the depleting fossil fuels due to its worldwide availability. As one of the thermo-chemical method, gasification has its advantage for H2 production, such as fast rate of hydrogen production and low cost. Gasification process often at high temperature is mainly accepted as the promising, attractive and effective technology to produce H2 from biomass. There are some vital process parameters which influence gas characteristic. In order to increase H2 concentration and reduce impurities, a reforming process following gasification is generally required, and effective catalysts can coordinate to achieve this. Thus, combining gasification and reforming processes are the most suitable method for obtaining H2 rich producer gas, and choosing a highly effective and suitable catalyst is the key challenge. Hydrogen can be obtained from two-stage gasification in industry level, which is used as chemical raw material. Keywords: Biomass, catalyst, energy, gasification, hydrogen, reforming.

Preparation of Eupatorium Adenophorum Based Porous Carbon with Microwave Heating using Response Surface Methodology

AbstractEupatorium adenophorum was utilized as raw materials for the preparation of activated carbon via microwave assisted steam activation. Influences of the three vital process parameters – activation temperature, activation duration and steam flow rate – have been assessed on the adsorption capacity and yield of Eupatorium adenophorum activated carbon (EAAC). The process parameters were optimized utilizing the Design Expert software and were identified to be an activation duration of 45 min, an activation temperature of 950 °C and a steam flow rate of 0.7 ml/min, with the resultant iodine number and yield being 1,010 mg/g and 20.13% respectively. The validity of process model to optimize the process parameters was verified using the analysis of variance (ANOVA). The key parameters that characterize quality of the porous carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1,142 m2/g, 0.84 ml/g and 3.3 nm respectively, for the sample corresponding to the optimized process conditions. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM). The present work strongly supports utilization of Eupatorium adenophorum as a potential precursor through microwave heating.

The Influence of Process Variables on Machinability of Hardened Tool Steel during the Hard Turning under Eco-Friendly Cooling Environment

Recent developments in cutting tool technology and its environmental impact have made significant revolutions in hard turning process thereby increasing the productivity level and enhancing the surface integrity of machined components competitively. In this experimental work, the machinability aspects, surface finish and tool life w`ere investigated during hard turning of hardened AISI D3 tool steel work materials with wiper geometry ceramic inserts under eco-friendly compressed air cooling environment. The process variables such as cutting speed, feed rate, tool nose radius, hardness levels of work materials and compressed air pressure were considered for this study. Since the tool nose design influences the machinability aspects, the cutting tool nose radius was considered as one of the vital process parameters. The design of experimental sequence and analysis of experiment data were carried with the help of Design Expert, DOE software. The combinations of Taguchi L16 orthogonal array and ANOVA technique have been applied for evaluating the process outcomes with reference to cutting variables. From the current experiment results, it is observed that combination of wiper ceramic insert with large nose radius and lower levels of compressed air pressure and work piece hardness (HRC) were resulting in higher surface quality with prolonged cutting tool life.

Experimental Investigation on Electroformed Copper-Based Zirconia Nanocomposites Aided by Ultrasonic

To improve the mechanical properties of the EDM electrode material, the electroforming process for fabricating copper-nanozirconia (ZrO2) particles composite aided by ultrasonic has been presented. In this research, some vital process parameters such as concentration of ZrO2, rotational speed and ultrasonic frequency have been evaluated. Two inspection criteria, content of ZrO2and micro hardness of deposited layer were employed to evaluate the fabrication quality of copper-nanozirconia (ZrO2) composite material. The experimental results indicate that nanocomposites grains electroformed aided by ultrasonic are refined. Their organizations are more uniform and dense, the surface is flatter and the microhardness of nanocomposites is significantly improved.

Experiment Study on Micro-Seam in Electrochemical Machining

In this study, we firstly developed a numerical electrochemical micro-machining (EMM) setup. Furthermore, the effects of five vital process parameters, applied voltage, electrolyte type, electrode shape and diameter, electrode feed rate on micro-seams machining accuracy and process stability were evaluated. The experimental results show that: Wire electrodes machining accuracy is higher than that of sheet electrode. With the wire electrodes diameter decreased from 0.2mm to 0.06mm, micro-seam width is reduced by 36.55%. With the wire electrode feed rate increased from 0.2mm/min to 0.6mmm/min, micro-seam width is reduced by 44.2%. Sheet electrodes machining stability is better than that of wire electrode. The number of machining stability of sheet electrode is 25% higher than that of wire electrode in the condition of 8V applied voltage.