Masroor Abro

A novel, low‐cost, porous geopolymer adsorbent incorporating silicon metal powder as a pore‐forming agent and graphene oxide for arsenic (As) removal from aqueous systems was synthesized, characterized, and evaluated. Extensive characterizations were conducted by scanning electronic microscopy (SEM), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR), revealing its performance in a fixed‐bed, adsorption column. XRD and SEM results indicated the formation of geopolymer at 27–29° of 2θ, achieved at a 50 ⁰ C curing temperature with 1wt% silicon metal powder and 1 wt% graphene oxide flakes, forming regular, uniform, interconnected pores. After the preliminary experimental investigations, COMSOL Multiphysics was used to simulate the adsorption process. The model was satisfactorily validated against experimental data, demonstrating its reliability under different operating conditions. The simulations were extended over an inlet concentration (C _i ) range of 50–150 ppb, bed height (Z _b ) of 2–6 cm, and feed flow rate (Q _f ) of 0.005–0.015 L/min. Results showed that increasing Z _b and C _i , enhanced arsenic removal efficiency (As%) by more than 99% and bed saturation time (t _s ) from 4000 to 1200 min, while at higher Q _f , both were reduced. Subsequently, response surface methodology (RSM) was employed to optimize operating parameters and understand the main and interaction effects of design factors on As% and t _s . ANN‐based predictive modeling was also conducted. Findings of RSM and artificial neural network (ANN) were closely aligned with experimental and computational fluid dynamics (CFD) results, indicating their reliability. Overall, Z _b exhibited a profound effect as compared to other factors. This study provides valuable insights for enhancing adsorption efficiency and system scalability.

The titanium dioxide nanoparticles (TiO2NPs) were synthesized and functionalized with bovine serum albumin (BSA) to yield TiO2@BSA nanocomposites for targeted drug delivery. The chemotherapeutic drug vinorelbine (VRL), used for non-small cell lung and breast cancer, was loaded into the nanocomposites by a cost-efficient sol-gel method. The UV-vis spectrum exhibited an absorption peak at 361 nm, confirming the formation of TiO2 NPs. In the FTIR spectrum, the grafting of BSA was indicated by specific band shifts. XRD and FESEM revealed well-dispersed spherical particles with an average crystallite size of ⁓20 nm, and EDX confirmed elemental composition. The zeta potential of −29 mV indicated colloidal stability with a drug loading efficiency of 62%. In vitro release studies demonstrated pH-responsive behavior, with 98% cumulative release at an acidic pH (5.5) compared to 20% at physiological pH (7.4), indicating the suitability of this formulation for tumor-targeted delivery. Higuchi and Korsmeyer-Peppas models were used for the kinetics study, indicating that the mechanism was controlled by diffusion and swelling. Cytotoxicity evaluation via MTT assay showed enhanced uptake and anticancer activity of VRL-loaded TiO2@BSANPs against MCF-7 cells compared with free VRL. These results suggest TiO2@BSA nanocarriers as efficient, stable, and selective platforms for cancer therapy.

Dissimilar welding of austenitic stainless steel and low alloy steel is widely employed in pressure vessels, petrochemical plants, power generation systems, and structural applications because it combines the corrosion resistance of stainless steel with the high strength of low alloy steel. However, acquiring high quality weld joints remains challenging due to differences in thermal expansion, chemical composition, and microstructural evolution. This paper examines the joint influence of electrode selection and post-weld heat treatment (PWHT) on the microstructure and mechanical properties of shielded metal arc welded (SMAW) dissimilar joint between AISI 4140 low alloy steel and AISI 201 austenitic stainless steel. Welded sample specimens were joined using E6013 and E308 electrodes and the samples were later subjected to PWHT at 600°C, 615°C, and 630°C for 1 h, followed by furnace cooling. Microstructural analysis was conducted using scanning electron microscopy (SEM), while tensile and Rockwell hardness tests were conducted to evaluate the mechanical performance of the welded joints. SEM characterization showed that the welded joint using E6013 electrode formed ferritic martensitic structures in the fusion zone, whereas the E308 electrode formed an austenitic dendritic microstructure containing retained δ-ferrite. It is noted that after the PWHT of welded samples the hardness variation was reduced and the tensile properties were improved. Among the examined specimens, the specimen welded with E308 electrode with PWHT at 615 °C revealed the optimal mechanical performance, achieving an ultimate tensile strength of 523 MPa, a yield strength of 392 MPa, and an elongation of 44%. These improvements resulted from an effective residual stress relief and microstructural stabilization during PWHT. The findings reveal that the joint use of the E308 electrode and PWHT at 615°C offers the most favorable balance of mechanical and microstructural stability for SMAW dissimilar welding of AISI 4140 and AISI 201 steels.

AISI 4340 steel is widely used in high risk industries due to its excellent mechanical strength and impact resistance. The mechanical properties of AISI 4340 steel can be significantly enhanced through heat treatment, particularly tempering at controlled temperatures. This study investigates the effect of tempering on the microstructure and mechanical properties of AISI 4340 steel. The experimental analysis includes characterization before and after heat treatment to assess changes in strength, toughness, and ductility. The results demonstrate that tempering at 450?C for 45 minutes optimally improves impact energy and ductility while slightly reducing hardness and strength. Conversely, tempering at 550?C results in a more pronounced increase in impact energy and ductility, but at the cost of a greater reduction in hardness and strength. Microstructural examination confirms the formation of tempered martensite, contributing to the observed mechanical behavior. The findings provide valuable insights into optimizing heat treatment parameters for AISI 4340 steel to achieve a balanced combination of strength, toughness, and ductility for industrial applications.

Eosin yellow (EY), a synthetic xanthene dye, is recognized for its high toxicity, posing serious threats to human health and aquatic environments. Chronic exposure to EY can result in skin irritation, respiratory disorders, and potential long-term organ damage due to its persistent and bioaccumulative nature. In this study, a polyaniline-based silver?palladium nanocomposite (PANI/Ag?Pd) was synthesized via the co-precipitation method and employed as an efficient nanocatalyst for the degradation of EY dye. The structural, morphological and elemental properties of the synthesized nanocomposite were characterized using UV?Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The UV?Vis and FTIR analyses confirmed the formation of the PANI/Ag?Pd nanocomposite with a notable red shift, indicating electronic interaction among the constituents. SEM images demonstrated the successful incorporation of Ag and Pd nanoparticles into the PANI matrix, while EDX confirmed the elemental composition. The nanocomposite exhibited remarkable photocatalytic performance under microwave irradiation, achieving up to 96.63 % degradation of EY dye. This study highlights the potential of PANI/Ag?Pd nanocomposites as a promising nanocatalyst for water purification. These findings contribute to the development of polymerstabilized nanomaterials as effective candidates for the remediation of dye-contaminated wastewater.

Computational fluid dynamics (CFD) was used to investigate influence of different gas sparger configurations and the presence of horizontal baffles on hydrodynamic characteristics in a flat bubble column. CFD results of time-averaged local and global gas holdup, liquid axial velocity, and Sauter mean diameter were experimentally validated. Subsequently, the validated CFD model was extended to investigate the effects of different gas sparger configurations, i.e., S₁, S₃, S₄, S₅, S₈, and S₇₂, and baffles arrangements, i.e., Config-A and Config-B on overall hydrodynamics at different superficial gas velocities (U_g = 0.0014 m/s and 0.0073 m/s). CFD results demonstrated significant influence of both sparger and U_g. Gas holdup and interfacial area increased with smaller, more numerous sparger openings, such that S₇₂ achieved ~1.55 times higher holdup and ~2 higher interfacial area than that of S₁. Spargers with fewer and larger openings induced stronger turbulence, which intensified early breakup and coalescence and broadened the bubble size distribution. Results revealed that spargers with many small openings (S₇₂) produced the narrowest distribution, retaining a high fraction of bubbles of initial size (5 mm), whereas spargers with fewer larger openings (S₁) generated broader distributions with significant coalescence, especially at higher U_g. The inclusion of baffles enhanced liquid circulation and gas–liquid mixing and contact. However, intensified turbulence below each baffle significantly increased coalescence, producing larger bubbles and resulting in only marginal changes in interfacial area despite increased gas holdup.

1. There are sections where content is repeated, such as the introductory remarks about the Life Cycle Assessment (LCA) and the industrial scale-up variability of Microbial Fuel Cells (MFCs). For example, the discussion about the LCA appears multiple...

Thermochemical processes utilizing biomass demonstrate promising prospects for the generation of syngas. In this work, a gasification process employing combination of an indigenous low-grade coal with two distinct biomass sources, namely rice husk (RH) and wood sawdust (WS), was explored. The gasification of the selected feedstock was performed using a double-staged multi-opposite burner (MOB) gasifier. A 3D computational fluid dynamics (CFD) model was employed to analyze the effect of kinetic and diffusion rates on the overall gasification performance of an entrained flow biomass gasifier. DPM was employed to track the particles’ trajectory, while the gas phase was treated as the continuous phase, and its behavior was predicted using a standard k-epsilon turbulent model. To calculate both the homogeneous and heterogeneous reaction rates, the finite rate/eddy dissipation model was implemented. The findings indicate that the char conversion efficiency exceeded 95% across all instances. Among the different reaction schemes, scheme E (which involved complete volatile and char combustion reactions) produced better results in comparison with published results, with less than 1% error. Hence, scheme E was validated and utilized for the rest of the simulated cases. The feeding rate has an inverse effect on the overall performance of the gasifier. An increase in feed rate decreases the CO and H₂ composition in syngas. The maximum CO value was observed to be 57.59% at a 1.0 O/C ratio with a 0.005 kg/s feed rate, and the maximum H₂ value was observed to be 16.58% in the same conditions for Lakhra coal samples. In summary, Lakhra coal exhibited better performance than other biomass samples due to its better fixed carbon and volatiles in its composition.