Optimal Parametric Conditions Research Articles

On the electrohydrodynamic jet printing of two-dimensional material-based inks for printed electronics

Electrohydrodynamic (EHD) jet printing is a well-known advanced manufacturing technique that uses electric fields to generate and control fine jets of fluid for high-precision deposition of materials. This method enables the printing of extremely fine features, making it ideal for applications such as printed electronics. However, little is known about the optimal conditions for achieving consistent jet stability and droplet formation, especially when dealing with complex and volatile fluids laden with two-dimensional (2D) nanoparticles. In this work, we study the electrohydrodynamic printing process of 2D material-based inks using toluene as the main carrier fluid. Adding ethyl cellulose to toluene allows us to increase the stability of the suspensions and establish the steady cone-jet mode of electrospray. A small amount of ethanol increases the fluid conductivity, stabilizing the steady cone-jet mode and reducing the jet diameter. The inks behave as leaky-dielectric, weakly viscoelastic liquids. For this reason, the jet diameter and minimum flow rate obey the scaling laws for electrospray of Newtonian liquids. We determine the optimal parameter conditions for the EHD printing of our inks directly onto a non-conductive substrate. The influence of the substrate's velocity on the width of the printed lines is analyzed. These findings enlarge the knowledge about how to increase the throughput in the EHD jet printing process while controlling the resolution of the printed lines when using volatile solvents, 2D nanomaterials, and non-conductive substrates.

A BIONIC-INSPIRED DRAGONFLY ALGORITHM FOR PARAMETRIC OPTIMIZATION AND DAMAGE INVESTIGATION DURING MACHINING OF MODIFIED POLYMER NANOCOMPOSITE

Polymer nanocomposite is commonly used to develop structural components of space, aircraft, biomedical, sensor, automobile, and battery sector applications. It remarkably substitutes the heavyweight metallic and nonmetallic engineering materials. The machining principles of polymer nanocomposites are intensely different and complex from traditional metals and alloys. The nonhomogeneity, abrasive, and anisotropic nature differs its machining aspect from conventional metallic materials. This investigation aims to execute the CNC drilling of modified nanocomposite using Graphene–carbon (G-C) @ epoxy matrix. The process constraints, namely, cutting speed (S), feed (F), and wt.% of graphene oxide (GO) vary up to three levels and are designed according to the response surface methodology (RSM) array. The nonlinear model is created to predict surface roughness (Ra) and delamination (Fd) on regression analysis. It has been found that the average error for Ra is 0.94% and for Fd it is 3.27%, which is acceptable in model predictions. The metaheuristics-based evolutionary Dragonfly algorithm (DA) evaluated the optimal parametric condition. The optimal setting prediction for the DA is observed as cutting speed (S)-37.68[Formula: see text]m/min, feed (F)-80[Formula: see text]mm/min, and wt.% of graphene oxide (GO)-1%. This algorithm demonstrates a higher application potential than the previous efforts in controlling Ra and Fd values. Both the drilling response values are found to be minimized when the cutting speed increases and the feed decreases. The best fitness value for the DA is 1.626 for surface roughness and 5.086 for delamination. This study agreed with the prediction model’s outcomes and the process parameters’ optimal condition. The defects generated during the sample drilling, such as fiber pull out, uncut/burr, and fiber breakage, were examined using FE-SEM analysis. The optimal findings of the DA module significantly controlled the damages during machining.

Sustainable hard machining under zirconia nano-cutting fluid: A step towards a green and cleaner manufacturing process

The present study deals with the machinability (flank wear, surface integrity, cutting temperature and power consumption) and sustainability (Carbon emission and noise emission) investigations during hard machining under dual nozzle assisted novel ZrO2 based nano fluid MQL condition considering Taguchi L27 OA design of experiment. 0.3 % wt. ZrO2 nanofluid MQL medium effectively reduce cutting temperature and found as 65 °C, which shows the effective cooling and lubrication properties of zirconia nanofluid. Improvement in surface quality has been observed with lower rate of flank wear. Depth of cut and feed are found to be the most influential factor affecting power consumption and carbon emission with contribution of 47.213 % and 60.861 % respectively. Noise emission mostly affected by the depth of cut with a contribution of 43.40 %. Optimal parametric condition yields d: 0.1 mm, f: 0.1 mm/rev and v: 80 m/min through WASPAS and sustainable towards manufacturing industries for cleaner hard machining.

Investigating the metabolism of four sulfonamides in grass carp via HPLC-MS for screening candidate materials of matrix reference material

An efficient, sensitive, and precise method for investigating the metabolism of four sulfonamides in grass carp has been established using high-performance liquid chromatography-mass spectrometry. By optimizing the experimental conditions, the method achieved a coefficient of determination above 0.999, with detection and quantification limits set at 0.5 μg/kg and 1.0 μg/kg, respectively. Recovery rates were between 92.90 % and 102.84 %, and relative standard deviations ranged from 1.70 % to 9.83 %, enabling the precise detection of these sulfonamides in grass carp tissue. The factors affecting the metabolic rate during the medicated bath process were investigated, and obtained the optimal parameter conditions for screening the candidate materials. The candidate materials screened through this method exhibit good stability when used to prepare matrix standard substances, this work not only provides a scientific basis for screening sulfonamide candidate materials but also offers insights for developing other matrix reference materials.

Optimizing the Extraction of Polyphenols from the Bark of Terminalia arjuna and an In-silico Investigation on its Activity in Colorectal Cancer.

The interconnection between different fields of research has gained interest due to its cutting-edge perspectives in solving scientific problems. Terminalia arjuna is indigenously used in India for curing several diseases, and its pharmacological activities are being revisited in recent drug-repurposing research. Efficient ultrasound-assisted extraction of phytochemicals from the bark of Terminalia arjuna is highlighted in this study. Following the optimization of the extraction process, the crude hydroethanolic extract is subjected to phytochemical profiling and an in-silico investigation of its anti-cancer properties. A three-level four-factor Box-Behnken design is exploited to optimize four operational parameters, namely extraction time, ultrasonic power, ethanol concentration (as the extracting solvent) and solute (in g): solvent (in mL) ratio. At the optimum parametric condition, the crude extract is obtained, and its GC-MS analysis is carried out. An analysis of network pharmacology (by constructing and visualizing biological networks using Cytoscape) combined with molecular docking reveals the potential antineoplastic targets of the crude extract. The ANOVA table exhibits the significance, adequacy and reliability of the proposed second-order polynomial model with the R² value of 0.917 and adjusted R² of 0.865. Experimental results portray the significant antioxidant potential of the prepared extract in its crude form. The GC-MS analysis of the crude extract predicts the extracted phytochemicals, while the constructed biological networks highlight its multi-targeted activity in colorectal cancer. The study identifies three phytochemicals viz. luteolin, β-sitosterol and arjunic acid as potent anti-cancer agents and can be extended with in-vitro and in-vivo experiments to validate the in-silico results, thus establishing lead phytochemicals in multi-targeted colorectal cancer therapies.

INVESTIGATIONS ON THE MACHINABILITY CHARACTERISTICS OF Al–Zn(5.4)–Mg(2.4)–Cu(1.4) ALLOY COMPOSITE USING TOPSIS APPROACH

In this research, stir casting was used to create the aluminium alloy (AA7075) composite filled with 10[Formula: see text]wt.% zirconia (ZrO2) particles as reinforcement. Die sinking electric discharge machining (EDM) was used to examine the machining characteristics of the proposed composite. The machining experiments were executed in accordance with the [Formula: see text] orthogonal layout. Here, the material removal rate (MRR) and surface roughness (SR) were taken into account as the output responses, and the discharge current ([Formula: see text]), pulse on-time ([Formula: see text]), and pulse off-time ([Formula: see text]) were taken as the machining parameters. To determine the optimal parameter conditions for the output responses, the technique for order preference by similarity to ideal solution (TOPSIS) approach was applied. According to the experimental findings, the optimum settings of the parameters are determined at 15[Formula: see text]amps of ‘[Formula: see text]’, 750[Formula: see text][Formula: see text]s of ‘[Formula: see text]’ and 50[Formula: see text][Formula: see text]s of ‘[Formula: see text]’. ANOVA results stated that ‘[Formula: see text]’ has the most notable factor with a contribution of 90.85%. The interaction effect of parameters on the responses was shown by the contour plots. The confirmatory experiment was finally conducted at the optimum machining parameter settings, and it was found that the error only occurred in 8.4%.

Application of ANN and RSM for Rhodamine B and Safranine-O Decolorization on Zinc-Carbon Battery Waste Derived Ag/CoFe-LDH/rGO Catalyst.

The present work is first aimed at recovering graphite from carbon rods of waste zinc-carbon (Zn-C) batteries for applications such as wastewater treatment, in order to contribute to the development of a sustainable environment. Then, a composite material, cobalt-iron layered double hydroxide combination with reduced graphene oxide, and with subsequent Ag nanoparticles deposition via NaBH4 reduction method (Ag/CoFe-LDH/rGO) was prepared for the catalytic activity of Rhodamine B (RhB) and Safranine-O (SO) as model contaminants from aquatic media. The catalytic activity of RhB and SO by Ag/CoFe-LDH/rGO in the presence of NaBH4 was studied to model and optimize the process parameters (NaBH4 amount, reaction time, initial dye concentration (Co), and catalyst dosage) via central composite design (CCD)-response surface methodology (RSM). Also, an artificial neural network (ANN) model was developed to estimate the catalytic activity of each dye using an RSM data set. The catalytic activities of 99.54% and 99.96% were obtained for RhB and SO dyes, respectively, under the optimal conditions: NaBH4 amount 12.32 mM, reaction time 3.19 min, Co 33.46 mg/L, and catalyst dosage 1.24 mg/mL for RhB dye; NaBH4 amount 16.76 mM, reaction time 3.06 min, Co 15.10 mg/L, and catalyst dosage 1.46 mg/mL for SO dye. The optimum conditions of process parameters by ANN with gray wolf optimizer (GWO) were in good agreement with the points determined the RSM-CCD. These results demonstrate that RSM and ANN approaches can be applied practically and efficiently to maximize the catalytic activity of RhB and SO by Ag/CoFe-LDH/rGO in the existence of NaBH4. On the other hand, from the kinetic and thermodynamic studies, the positive activation enthalpy, ΔH# and the negative activation entropy, ΔS# values for each dye demonstrated that the catalytic performance was endothermic and less random at the solid/liquid interface.

Corncob waste derived carbon with sulfonic acid group: An efficient heterogeneous catalyst for production of ethyl levulinate as biodiesel additives

Alkyl levulinate is a biomass-based chemical compound used as a fuel additive. This research aims to produce ethyl levulinate from levulinic acid and ethanol using esterification with the assistance of a heterogeneous sulfonated carbon catalyst. The carbon sulfonate catalyst is obtained from corncob waste that has undergone carbonization at 300 °C and sulfonation using sulfuric acid at a temperature of 150 °C for 8 h. The catalyst is used for esterification with predetermined operating variables using Box-Behnken Design (BBD) on the response surface methodology (RSM). The result shows significant variables for ethyl levulinate esterification are catalyst loading and esterification time. The FTIR analysis indicates the presence of S=O bonds in the sulfonated carbon catalyst. The XRD and SEM analysis shows that the sulfonated carbon catalyst is in amorphous and mesoporous form. Catalyst reusability demonstrates that the corncob-derived carbon sulfonate catalyst can be used up to 3 times. The optimum condition for esterification is 9 h of reaction, 10 % catalyst loading, and a molar ratio of levulinic acid to ethanol of 1:10, which has 83.15 % conversion. These results present the optimum parameter conditions for an efficient heterogeneous catalyst from corncob for producing ethyl levulinate.

An ultrasound assisted dispersive micro solid-phase extraction and a composite ionic liquid-metal organic framework for sixteen polycyclic aromatic hydrocarbons analysis in fruit juice and environmental water samples

Aluminum-based metal organic framework composite containing ionic liquid was prepared and used as sorbent for extraction of sixteen polycyclic aromatic hydrocarbons in list of priority pollutants of United States Environmental Protection Agency before their analysis by gas chromatography/mass spectrometry. The dispersive micro solid-phase extraction method, known as a simple and fast method, was preferred as the extraction method. The optimized parameter conditions were 5 mL of sample solution, 10 min sonication by ultrasonic bath, 30 mg of sorbent, 30 °C extraction temperature, 0.1 mL of hexane as elution solvent with 5 min elution time. The suggested method presented that limit of detection and limit of quantification were in the range of 0.01–0.10 μg l-1, and 0.04–0.33 μg L-1, respectively. The intra-day and inter-day repeatability were within the ranges of 1.18–4.88 % and 1.02–5.06 %, respectively. The recoveries for polycyclic aromatic hydrocarbons in peach juice, cherry juice, tap water and rain water samples were obtained in the range of 84.9–99.9 % for spiked 5, 50 and 100 μg l-1 standard polycyclic aromatic hydrocarbons solution.

Study on separation of 6–0 mm low rank high sulfur lignite by FGX dry separation bed

ABSTRACT Coal is an essential primary energy for the national economy and people’s livelihood. In recent years, with the rapid growth of the consumption of high-quality coal resources, Lignite with a low degree of metamorphism has been extensively exploited and utilized. In this paper, desulfurization and ash reduction treatment of 6–0 mm fine-grade low-grade high-sulfur Lignite was carried out using a FGX dry separation bed (FGX FGX compound dry separation bed). The migration and distribution of differentiated density particles in the bed under the action of cascade air flow were mainly studied, and the influence of vibration intensity (amplitude and frequency) on the separation effect of fine-grade low-grade high-sulfur Lignite was explored. At the same time, the material distribution characteristics of each section in the direction of the discharge edge of the bed were systematically analyzed, the material distribution area of the bed was determined, the optimal operating parameters (A = 2.8 mm, f = 26 Hz, V = 2.29 m/s) were obtained, and the sorting test was carried out under the optimal parameter conditions. The test results show that when the vibration frequency f = 26 Hz, the sulfur segregation degree of bedding materials reaches the maximum Ss = 0.36, and the sulfur content of materials in I, II, and III regions is 0.85%, 5.47%, and 18.78%, respectively. The stratification effect of bedding materials is the best. When A = 2.8 mm, the material sulfur segregation reaches the minimum value of Ss = 0.28, and the average sulfur content of materials in I, II, and III regions is 0.78%, 5.46% and 18.27%, the material is stratified according to density. When the airflow rate is 2.55 m/s. The stratification effect of bed material is best according to density. The clean coal yield is 69.87%, and the sulfur content is 0.98%. The gangue yield is 30.13%, and the sulfur content is 18.66%. The Ep value of energy deviation is 0.11 g/cm3, which realizes high precision dry desulfurization and upgrading fine-grade, low-grade, and high sulfur lignite.

Response surface methodology optimization of sodium diclofenac adsorption using activated carbon derived from falcata tree sawdust

The presence of sodium diclofenac in water is a significant problem due to its adverse effects on terrestrial and aquatic organisms. Thus, this study investigated the Falcata tree sawdust as the precursor of activated carbon for the adsorption of diclofenac in an aqueous solution. The characterization of falcata tree sawdust-activated carbon (FTSAC) was evaluated by SEM and FTIR analysis. The activated falcata sawdust converted to activated carbon has a 30 % yield. The optimal values for the operating parameters, FTSAC dosage, initial sodium diclofenac concentration, reaction time and pH, were determined using the central composite design (CCD) of the response surface methodology (RSM). The optimal removal efficiency suggested by CCD is 93.98 % with the optimum conditions of parameters of 0.80 g FTSAC dosage, 200 ppm initial sodium diclofenac concentration, 20 min reaction time, and pH 4. These optimal values of parameters were validated by an actual experiment, and the result (average removal efficiency: 92.08 %) is within a 95 % confidence interval. On the other hand, the pseudo-second-order (R2 = 0.9991) kinetic model depicts the rate of absorption of FTSAC adsorbing SD. Moreover, the Langmuir-Freundlich isotherm or Sips isotherm model (R2 = 0.9904) is the best-fit model that describes the heterogeneous adsorption dynamics of FTSAC surfaces. This study indicates that falcata sawdust can serve as a promising and viable alternative raw material to produce activated carbon.

Sintering parameter optimization by inverse analysis in direct metal deposition of Inconel 718

PurposeThe net power delivered to the surface of parts (i.e. the actual heat flux) is a key parameter in the laser melting process and its exact control has a great impact on the numerical solutions. In this paper, the impact of laser additive manufacturing parameters including laser power, scanning speed and powder injection rate on thermal efficiency, net power delivered to the part and power loss due to powder flow has been investigated.Design/methodology/approachThe response surface method was applied to measure the net laser power in laser deposited Inconel 718 using k-type thermocouples. The temperature history obtained by thermocouples was used to calculate the net power delivered by inverse analysis method. The applied model is Rosenthal's optimized model, in which all the thermal properties of the material are considered to vary with temperature.FindingsThe results indicated that the thermal efficiency, power delivered to the part and power loss can be optimized simultaneously at laser power of 400 W, scanning speed of 2 mm/s and powder injection rate of 200 mg/s. The microstructure analysis indicated that a high-quality sample without microstructural defects was formed under optimal condition of parameters. Moreover, the primary dendrite arm spacing for the optimal sample was higher than that obtained for other samples.Originality/valueThe novelty of this research summarized as follows: Prediction of the thermal efficiency and power loss during the laser metal deposition of Inconel 718 superalloy using the inverse analysis. Finding the optimal values of thermal efficiency, power delivered to the surface and power loss in the laser metal deposition of Inconel 718 superalloy. Investigating the effect of laser power, powder injection rate and scanning speed on the thermal efficiency and power loss of Inconel 718 superalloy during the laser metal deposition.

Preparation and Performance of a Cr/CrN/TiAlCN Composite Coating on a GCr15 Bearing Steel Surface

In order to enhance the surface properties of GCr15 bearing steel, a TiAlCN coating with a low friction coefficient, high hardness, and excellent adhesion was fabricated. The TiAlCN multilayer coating was deposited onto the GCr15 bearing steel surface using magnetron sputtering technology, and optimal coating parameters were achieved by adjusting the number of layers, sputtering power of the graphite target, and coating duration. The experimental results showed that adding Cr/CrN as a transition layer between GCr15 bearing steel and TiAlCN significantly improved multiple properties of the coating. Adding carbon atoms caused TiAlN to dissolve into a TiAlCN structure, enhancing multiple properties of the coating. With the increase in the sputtering power of the graphite target material, the hardness, friction, and wear performance of the coating showed a trend of first increasing and then decreasing. The hardness of the coating gradually increased with time, and the friction coefficient and wear amount first decreased and then increased. When the sputtering power of the graphite target material was 100 W and the coating time was 4800 s, the coating performance was optimal. The hardness was 876 HV, the friction coefficient was 0.42, the wear amount was 1 × 10−4 g, and the wear rate was 2.8 × 10−6 g/m·N under optimal process parameter conditions.

Stacking Effect of Carbon/Glass Fiber During Drilling Operation of Laminated Polymer Composite

Nowadays, fiber stacks are extensively used in the aircraft and structural component manufacturing industries. It is mainly due to their excellent mechanical and physiochemical performances. The different stacking sequences of fiber materials expand the structural properties due to high-strength carbon fiber and low-cost glass fiber. The fragile and anisotropic conduct of Carbon (Cf) and Glass (Gf) laminates generates different types of complex machining issues. This article focuses on the Drilling test of Carbon/glass fiber hybrid composites using different stacking sequences. The effect of varying stacking orders is explored in this study to identify a feasible composite. The control of varying constraints, namely, spindle speed (N), feed rate (f ), and stacking sequence (SS) of carbon (Cf) and glass fiber (Gf) reinforcement, is performed to achieve the optimal parametric condition. The finding reveals that sample A (C4G4) stacking sequence provides an acceptable value for thrust force 59.05 N and delamination 1.0001 for high drilling efficiency. The stacking technique of carbon/glass layers can be endorsed to the manufacturing sector for cost-effective composite development and a defect-free machining environment.

Nutrient recovery from manure digestate by using waste magnesite powder and bone meal as sustainable substitutes for struvite precipitation

AbstractBACKGROUNDStruvite (MgNH4PO4.6H2O) precipitation is a sustainable approach that can offer simultaneous removal/recovery of nutrients from biogas plant effluents. However, most biogas plant effluents contain a higher molar concentration of nitrogen (N) than magnesium (Mg) and phosphorus (P). Therefore, the external addition of Mg2+ and phosphate (PO43‐) salts is needed to maximize the recovery. In this study, Mg‐rich waste magnesite powder and P‐rich bone meal were used as sustainable additives. The Box–Behnken design was applied to determine optimum conditions of process parameters (pH, Mg:N and P:N molar ratios) to maximize ammonium‐nitrogen (NH4‐N), PO4‐P and Mg2+recoveries.RESULTSNH4‐N, PO4‐P and Mg2+ recoveries were in the ranges 78.5%–96.9%, 69.2%–96.3% and 75.1%–99.9%, respectively. The actual and predicted values showed significant consistency, indicating that the model is satisfactory. Under optimum conditions (pH = 9.0, Mg:N = 2.2, P:N = 1.8), 97.8 ± 0.1% NH4‐N, 96.6 ± 0.31% PO4‐P and 84.4 ± 0.9% Mg2+ recovery were attained. The X‐ray diffraction results confirmed the sole presence of struvite crystals. Scanning electron microscopy images showed irregular prismatic orthorhombic crystals and amorphous material depositions on precipitates of ~25 μm crystal size. The product was 49% struvite with 15.2% P content. The heavy metal content was lower than regulatory limits.CONCLUSIONEven though waste material and industrial by‐products have been used as additives in this process, high NH4‐N and PO4‐P recoveries were recorded under optimum conditions. These results are promising and illustrate a powerful example of industrial symbiosis, and the precipitate containing struvite can serve as a valuable product. © 2024 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

An improvement in the mechanical properties of polypropylene/ethylene-propylene-diene monomer/titanium dioxide nanocomposite obtained by fused filament fabrication

In the present research, the PP/EPDM/TiO2 nanocomposite was fabricated using the fused filament fabrication process to improve the mechanical properties of the obtained samples. For this purpose, first the response surface methodology was used to investigate the effect of TiO2 content, nozzle temperature and printing speed on the responses of tensile strength and elongation. Then, the desirability function method was applied to find the optimal condition of the process parameters. The fracture surface of the tensile samples was also studied by scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis to find a relationship between the microstructure and mechanical properties of the fabricated samples. The results indicated that the highest elongation of samples (144.9%) was attained at a TiO2 content of 4 wt%, while the tensile strength of samples was maximized (24.6 MPa) at a TiO2 content of 2 wt% due to fine dispersion of the nanoparticles. An increase in the nozzle temperature from 200 to 225°C led to an enhancement in the tensile strength (11.2%) and elongation (15.7%) of samples because of the good viscosity of the filament, whereas the tensile strength (6.6%) and elongation (11.1%) of samples were decreased with the increase of nozzle temperature from 225 to 250°C because of the thermal degradation of filament. Moreover, when the printing speed raised from 20 to 40 mm/s, the tensile strength initially improved by 2.7% and then decreased by 1.2%, but the elongation continuously decreased by 6.3%. Nevertheless, the concurrent enhancement of the tensile strength and elongation has been obtained at a TiO2 content of 2.5 wt%, nozzle temperature of 227°C and printing speed of 28 mm/s.

Spatiotemporal reshaping of femtosecond laser pulses on interaction with gas sheath at ionization saturation intensity regime

Interaction of intense ultrashort laser pulse with gases generates a transient spatiotemporal electron density distribution via field ionization, which may lead to the spatiotemporal reshaping of the pulse, viz., its beam profile, pulse width, etc. Here, we present an experimental study on ultrashort laser pulse interaction with argon gas sheath in an ionization saturation intensity regime (∼1015–1017 W/cm2). The present investigation has been performed using a 6 mJ, 1 kHz, and 55−60 fs Ti:Sapphire laser pulse interaction with a ∼2.5 mm long argon sheath. After the laser gas interaction, the laser spatial profile exhibits a multi-ring structure around a central maximum spot. Laser gas interaction parameters, such as laser intensity, gas pressure, etc., affect the ring pattern significantly. Under optimum parameter conditions, the laser pulse has two rings in spatial profile, and the pulse width of the central spot is self-compressed to ∼35 fs. A theoretical calculation reveals that the laser beam’s spatiotemporal profile evolves as it propagates inside the gas sheath. The calculation also demonstrates that the gas ionization profile plays a crucial role in the spatiotemporal reshaping and self-compression of the laser beam. The calculation also shows that the generation of concentric ring patterns in the spatial profile is mainly due to the ionization of argon atoms into Ar+, Ar2+, and Ar3+ species in the interaction region. Such self-compressed laser pulses with concentric ring beam profiles may be useful for high-harmonic generation and shorter attosecond pulse trains.

MICRO-EDM OF TI–6AL–4V USING VARIOUS TOOL MATERIALS: MULTI-RESPONSE OPTIMIZATION AND SURFACE CHARACTERIZATION

In this paper, experimental analysis was performed during micro-electrical discharge machining (micro-EDM) of titanium alloy Ti–6Al–4V (grade 5) using three types of tools viz. copper (Cu) tool, tungsten carbide (WC) tool, and synthetic graphite (Gr) grade three tool. The main process parameters were taken as (a) pulse on time ([Formula: see text]), (b) pulse off time ([Formula: see text]), (c) voltage (V), and (d) capacitance (C). The output responses were taken as the material removal rate (MRR) and tool wear rate (TWR). Taguchi method coupled with grey relational analysis (GRA) (L[Formula: see text] orthogonal array) technique was applied to optimize the input process parameters for both the responses. Scanning electron microscopy (SEM) analysis of the workpiece and tool was also performed to investigate the morphology of the machined surface and tool surface. Energy-dispersive spectroscopy (EDS) analysis was performed to investigate the elemental composition of the machined surface. The experimental finding reveals that tungsten carbide is the most suitable tool material for machining the chosen workpiece for obtaining optimal MRR and TWR. The optimum condition for the copper tool was found as 180[Formula: see text]V, 1000[Formula: see text]pf, 10[Formula: see text][Formula: see text]s ([Formula: see text]), and 10[Formula: see text][Formula: see text]s ([Formula: see text]). Meanwhile, the optimum parametric condition for tungsten carbide and graphite tools was found to be the same as 240[Formula: see text]V, 100[Formula: see text]pf, 20[Formula: see text][Formula: see text]s ([Formula: see text]), and 5[Formula: see text][Formula: see text]s ([Formula: see text]).

Strategic enzymatic biodegradation of pharmaceutical pollutant carbamazepine by bacteria Rhodococcus zopfii

Carbamazepine is frequently detected in wastewater, impacts human health and the environment. This study evaluates the biodegradation of carbamazepine by Gram-positive bacteria Rhodococcus zopfii, specifically optimum biodegradation conditions and extracellular enzyme roles. The carbamazepine biodegradation optimization and bacteria growth for initial concentrations of carbamazepine, pH and temperatures were investigated. Extracellular enzyme assays were also examined. For the carbamazepine biodegradation, the optimum initial concentration, pH and temperature were at 10 mgL-1, pH 7 and 40 ℃, respectively with the carbamazepine biodegradation percentages ranging from 99.92 ± 0.04 % to 99.98 ± 0.14 %. The optimum parameter conditions for the bacteria growth were 5 mgL-1, pH 7 and 40 ℃ with a range from 9.61 ± 0.01 log CFUmL-1 to 10.35 ± 0.00 log CFUmL-1. The bacteria growth and the carbamazepine biodegradation occurred sequentially, with the bacteria growth preceding the carbamazepine biodegradation. The highest extracellular enzyme secreted by R. zopfii was aldehyde oxidase, followed by oxygen oxidoreductase, catechol 1,2 dioxygenase and catechol 2,3 dioxygenase. At the early of the biodegradation, oxygen oxidoreductase and aldehyde oxidase were secreted, then followed by catechol 1,2 dioxygenase and catechol 2,3 dioxygenase. A linear correlation between oxygen oxidoreductase with the biodegradation of carbamazepine was identified. Such phenomenon revealed R. zopfii metabolised carbon from the phenolic compound, thus reducing carbamazepine toxicity for defence and biodegradation mechanisms compared to growth. This study provides vital information for the biodegradation of carbamazepine using Gram-positive bacteria R. zopfii as a sustainable technology, mimics nature that is beneficial for wastewater treatment management and industry application.

Process parameters optimization and performance analysis of micro-complex geometry machining on Ti6Al4V

The aeronautical industry relies on high-performance equipment that demands materials with exceptional engineering attributes, such as the Ti6Al4V alloy. However, the complexity of the parts used in these applications presents challenges related to stack-up tolerances during assembly. Therefore, conventional machining processes are not economically viable due to their two-step nature solution (machining and surface treatment) and their inability to achieve the required accuracy level, particularly given the alloy’s hard-to-cut nature. In this matter, wire electric discharge machining (WEDM) emerges as an attractive alternative for fabricating complex geometries. This research focuses on evaluating the potential of the WEDM process for machining micro-complex profiles. A comprehensive range of process parameters, including servo voltage (Vs), pulse on time (Ton), pulse off time (Toff), and wire speed (Ws), are studied using a Taguchi-based design of experiments. The results are analyzed through parametric significance analysis, parametric control analysis, surface morphological analysis using scanning electron microscopy, and modified layer analysis. Additionally, both mono-objective and multi-objective process optimization techniques are employed to achieve superior accuracy and speed. The findings indicate that Ton and Ws have the most significant influence on both cutting speed and spark gap, whereas Vs and Toff play a crucial role in determining the accuracy index. In addition, adequate flushing, reduced wire speed (economically viable), and stability of the spark are recommended to attain a lower spark gap and higher accuracy. The confirmatory experiments show that the optimal parametric conditions of Vs = 60 V, Toff = 30 μs, Ton = 8 μs, and Ws = 6 mm/s provide the highest speed of 3.4 mm/min, minimum spark gap of 0.344 mm, and accuracy index of 98.72%. The findings will contribute to enhancing manufacturing efficiency, precision, and cost-effectiveness in the aeronautical industry, meeting the demand for high-quality components with tight tolerances.