Search Results (244)

The field of nanotechnology has witnessed a paradigm shift towards eco-friendly and sustainable synthesis methods for nanoparticles due to increasing concerns over environmental toxicity and resource sustainability. Among various metal oxide nanoparticles, zirconium dioxide (ZrO₂) nanoparticles have garnered significant attention owing to their exceptional thermal stability, biocompatibility, mechanical strength, and catalytic properties. Doping ZrO₂ with transition metals such as copper (Cu) further enhances its physicochemical attributes, including antibacterial activity, redox behaviour, and electronic properties, rendering it suitable for a diverse range of biomedical and industrial applications. In the present study, we report the green synthesis of copper-doped ZrO₂ nanoparticles (Cu-ZrO₂-CO NPs) using an aqueous extract of Calendula officinalis (marigold) flowers as a natural reducing and stabilizing agent. The complete characterization was performed using UV–vis spectrophotometry, dynamic light scattering (DLS), zeta potential, FTIR, SEM, EDAX, and XRD, revealing its size to be around 20–40 nm and zeta potential as −20 mV, indicating nano size and stability. The biocompatibility of the as-synthesized nanoparticle was analyzed in vitro using fibroblast cell viability and haemolysis assay, and in vivo using brine shrimp assay. The nanoparticles were safe up to a dose of 50 μg/mL, showing more than 95% cell viability and less than 2% haemolysis, which is within an acceptable range. Finally, the anticancer activity was explored for A549 cells by MTT assay and live-dead assay, with an IC50 value of 38.63 μg/mL. The chorioallantoic membrane (CAM) model was used to assess the anti-angiogenesis potential of the Cu-ZrO₂-CO NPs. The results showed that the nanoparticles could kill the cancer cells via apoptosis, and one of the reasons for the anticancer effect was angiogenesis inhibition. Further research is needed using other cancer cell lines and animal tumour models. Full article

Oily wastewater treatment is crucial for protecting the environment and ensuring sustainable water use. The current study examines the effectiveness of electrocoagulation in treating oily wastewater by conducting several batch experiments designed to determine the best operating conditions. Various factors affecting the performance of electrocoagulation, such as applied current density, electrode type, and pH, were studied. The results indicate that, under ideal conditions, electrocoagulation worked very well. The best results were obtained by involving an applied current density of 6 mA/cm², a mild steel anode, and a pH of 6.7. Under these conditions, the process removed 94% of the chemical oxygen demand (COD) from the oily wastewater. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDAX) were used to characterize the residual sludge left in the reactor. The characterization results show that the oily pollutants were successfully removed through electroflotation. Additionally, oil precipitate particles were easily coated during the electrocoagulation operation. The findings show that electrocoagulation is an effective method for treating oil-contaminated wastewater. Full article

The aim of the research was to analyse the impact of peening each of the beads on the properties of a butt joint made of S960QL steel welded with ceramic backing on a robotic workstation using the 135 (MAG) method, and to determine the impact of pneumatic needle peening on the stress level. This analysis was based on a comparison of three butt joints: in the as-welded state, with each weld bead peened and post-weld heat treatment—stress relief annealing—performed. High-frequency peening (90 Hz) of each weld was performed to reduce stresses in the welded joint by introducing tensile stresses into it. A Weld Line 10 pneumatic hammer from PITEC GmBH was used for this purpose. The test joints obtained were tested in accordance with the requirements of EN ISO 15614-1. In order to determine the state of residual stresses, stress measurements were carried out using the Barkhausen effect based on the testing procedure of the technology supplier, NNT. This meter measures the intensity of the Barkhausen effect using a standard probe (with a single core). In order to verify the stress measurement using the Barkhausen method, stress measurements were performed using the XRD sin 2ψ technique based on the X’Pert Stress Plus program, which contains a database of material constants necessary for calculations. Structural studies, including phase analysis and crystallographic grain orientation, were performed using the backscattered electron diffraction method with a high-resolution scanning electron microscope and an EBSD (Electron Backscatter Diffraction) detector, as well as EDAX OIM analysis software. In addition, X-ray diffraction testing was performed on a Panalytical X’Pert PRO device using filtered cobalt anode tube radiation (λ = 1.79021 A). Qualitative X-ray phase analysis of the tested materials was performed in a Bragg–Brentano system using an Xcelerator strip detector. The tests showed that the high-frequency peening of each bead did not cause negative results in the required tests during qualification of the S960QL plate-welding technology compared to the test plates in the as-welded and post-stress-relief heat treatment states. Interpass peening of the weld face and HAZ resulted in a reduction in residual stresses after welding at a distance of 15 mm from the joint axis compared to the stress measurement result for the sample in the as-welded condition. This allows for a positive assessment of peening in terms of reducing the crack initiator in the form of the concentration of tensile stresses in the area of the fusion line and HAZ. Full article

Background/Objectives: Hepatotoxicity remains a major therapeutic challenge driven by oxidative stress and inflammation. This study investigated the hepatoprotective potential of green-synthesized silver nanoparticles derived from ethanolic garlic peel extract (GPE-Ag) against pyrogallol-induced liver injury. Methods: Adult rats were randomly assigned into four groups: a control group, a pyrogallol-treated group, a group receiving GPE-Ag nanoparticles (50 mg/kg, orally) for 28 days, and GPE-Ag + pyrogallol co-treated. Results: The garlic peel extract was analyzed by high-performance liquid chromatography (HPLC), revealing high levels of phenolic acids (66.83 µg/g) and flavonoids (59.81 µg/g), predominantly ellagic, gallic, and syringic acids, along with kaempferol, quercetin, and myricetin. The synthesized GPE-Ag nanoparticles were characterized using UV–Vis spectroscopy, transmission and scanning electron microscopy (TEM and SEM), zeta potential, dynamic light scattering (DLS), and energy-dispersive X-ray analysis (EDAX). GPE-Ag treatment markedly attenuated pyrogallol-induced hepatic injury by reducing serum liver enzyme levels, lipid peroxidation, and proinflammatory cytokines, including interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and nuclear factor-kappa B (NF-κB), while enhancing the activities of antioxidant enzymes, catalase (CAT) and glutathione peroxidase (GPx), as well as the anti-inflammatory cytokine interleukin-10 (IL-10). Histological examination further confirmed the restoration of normal hepatic architecture. Conclusion: This study provides the first evidence that garlic peel–derived silver nanoparticles exert potent hepatoprotective effects through redox homeostasis restoration and modulation of the NF-κB signaling pathway. These findings highlight GPE-Ag as a promising, sustainable nanotherapeutic candidate for managing chemically induced liver injury. Full article

The integration of nanoengineered materials into concrete systems has emerged as a promising strategy for enhancing structural performance and sustainability. This study presents a hybrid experimental-analytical investigation into the use of multilayer graphene as a smart admixture in high-performance concrete. The research combines mechanical testing, microstructural characterization, and a multi-objective optimization model to determine the optimal graphene dosage that maximizes strength gains while minimizing carbon emissions. Concrete specimens incorporating multilayer graphene (ranging from 0.01% to 0.10% by weight of cement) were tested over 7 to 90 days for compressive, tensile, and flexural strengths. Simultaneously, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analyses revealed crystallinity enhancement, pore densification, and favorable elemental redistribution due to graphene inclusion. A normalized composite objective function was formulated to balance three maximization targets—compressive, tensile, and flexural strength—and one minimization goal—carbon emission. The highest objective score (Z = 1.047) was achieved at 0.10% graphene dosage, indicating the optimal balance of strength performance and environmental efficiency. This dual-framework study not only confirms graphene’s reinforcing effects experimentally but also validates the 0.10% dosage through mathematical scoring. The outcomes position of multilayer graphene as a powerful additive for high-strength, low-carbon concrete, especially suited for infrastructure in hot and arid environments. The proposed optimization approach provides a scalable pathway for performance-based graphene dosing in future innovative concrete formulations. Full article

The citrate–nitrate method was employed to synthesize the magnesium chromite (MgCr₂O₄) spinel, followed by calcination at 700 °C for 3 h. The synthesized compound was analyzed using techniques including powder XRD, SEM-EDAX, FTIR, UV-DRS, and LCR Meter. The structural analysis was conducted using an X-ray diffractometer, which revealed the formation of the cubic crystal symmetry of the sample with the corresponding Fd-3 m space group. The average crystallite size of the sample was calculated around 15.38 nm. Using tetrahedral and octahedral positions, the lattice vibrations of the associated chemical bonds were identified using Fourier transform infrared (FTIR) spectroscopy. SEM (scanning electron microscopy) micrographs showed that the spherical nature of the particles and the constituent particles were between 10 and 40 nm in size. The optical bandgap value was evaluated using Tauc’s plot. Pellets of the powdered sample were prepared for determining the dielectric aspects, such as the dielectric constant (ε′) and tangent loss (tanδ), in the frequency range of 10 Hz–8 MHz at room temperature. The charge transport mechanism was explored from the complex impedance spectroscopy study. The obtained results indicate that magnesium chromite may be a potential candidate in the fabrication of sensors, micro-electronic devices, etc. Full article

A widely used approach for synthesizing hydroxyapatite (HA) particles is the wet chemical precipitation method, favoured for its cost-effectiveness and straightforward process. Incorporating organic macromolecules with polar functional groups, such as COOH and OH, during synthesis can impact the properties of the resulting HA particles. These functional groups enhance the affinity for positively charged Ca²⁺ ions, promoting HA crystal nucleation in the solution. In this study, solutions at different concentrations of chitosan and sodium alginate are used as nucleation medium for the HA particles in order to decrease their particle size. The calcium and phosphate precursor solutions were adjusted to a pH of 12 and added to the polymer solution with a concentration varying from 5 to 10% w/v, reported to the stoichiometric mass of HA according to the synthesis reaction. After synthesis, the resulting powder was calcinated at 1000 °C. The effects that the polymers have on the properties of HA particles were monitored using SEM, FT-IR, EDAX, DLS, and TGA before and after the thermal treatment to see how the system evolves till crystallization of HA occurs. The largest decrease in average particle diameter—67.7%—was observed in the HA + Alg 10% sample, although a reduction in particle size was evident in all samples. Full article

This study explores a green synthesis approach for creating a nanocomposite material consisting of zinc oxide (ZnO) nanoparticles decorated with reduced graphene oxide (rGO), utilizing Clitoria ternatea flower extract as a biogenic reducing agent. The objective was to leverage the phytochemicals present in the flower extract to form ZnO nanoparticles, enhance their properties through rGO integration, and evaluate their structural and photocatalytic characteristics. The nanocomposite was characterized using a comprehensive suite of techniques, including XRD, FTIR, UV–Vis spectroscopy, DLS, zeta potential, SEM, and EDAX. To assess the in vitro biocompatibility, an MTT assay was performed on the normal fibroblast cell line 3T3L1. The nanocomposite exhibited minimal cytotoxicity with over 86% cell viability at concentrations up to 320 μg/mL. Additionally, hemolysis assays demonstrated that the nanocomposite induced less than 5% hemolysis, indicating excellent hemocompatibility. In an in vivo evaluation, zebrafish embryos exhibited no deformities, and the cumulative hatchability was also not affected up to a dose of 50 μg/mL. The exploration of environmental remediation was studied using bromophenol dye degradation, which showed a 65% dye degradation within 30 min of exposure to the composite and sunlight. The outcome of the study showed successful formation of ZnO and its composite with rGO (CT-rGO-ZnO), exhibiting excellent biocompatibility and improved photocatalytic properties. The material demonstrates promise for applications in environmental remediation and energy-related fields. The environmentally friendly nature of the synthesis approach also makes it a valuable contribution toward sustainable nanotechnology. Full article

The need to use environmentally friendly and cost-effective methods to remove heavy metals from wastewater is a permanent concern worldwide. Eggshells have been indicated as a worthy biosorbent for the adsorption of heavy metals due to their bioavailability and composition. In the present study, the absorption capacity of untreated chicken (CEs) and quail (QEs) eggshells for the removal of Pb and Zn ions from aqueous solutions was evaluated at room temperature and 40 °C, using four types of agitation systems: classical and orbital agitation and ultrasonic and microwave-assisted activation. The monitoring of aqueous solutions was performed by electrochemical and spectro-analytical (AAS) procedures before and after the adsorption process. FTIR and RAMAN spectroscopy, SEM-EDAX microanalysis, and X-ray diffraction were used to investigate the characteristics of eggshell samples post-exposure to Pb²⁺ or Zn²⁺. For any type of agitation and temperature, the CEs were able to induce more than 65% removal efficiency for lead and over 80% in the case of zinc. Concerning the Zn removal efficiency of QEs, notable results were recorded when microwaves were applied (>90%) and at 40 °C for orbital shaking and ultrasound (>80%). The results of the present study may offer new and valuable information for the optimal removal of Pb²⁺ and Zn²⁺ using eggshells, thus contributing to the sustainable management of waste through the recycling of this type of biomaterial. Full article

Soil contamination with heavy metals poses a significant risk to human health and ecological systems through multiple exposure pathways: direct ingestion of crops, dermal contact with polluted soil, and bioaccumulation within the food chain. This study analyses eleven composite soils, each collected in triplicate from different sites in Iași County, four of which are designated Natura 2000 protected areas (Mârzești Forest, Plopi Lake—Belcești, Moldova Delta, and Valea lui David). The assessment includes measurements of soil humidity by the gravimetric method, pH, and organic matter content, examined in relation to heavy metal concentrations due to their well-established interdependencies. For heavy metal determination, energy-dispersive X-ray spectroscopy (EDS) using an EDAX system (AMETEK Inc., Berwyn, PA, USA) and X-ray fluorescence spectrometry (XRFS) with a Vanta 4 analyser (Olympus, Waltham, MA, USA) were employed. Additionally, scanning electron microscopy (SEM) with a Quanta 450 microscope (FEI, Thermo Scientific, Hillsboro, OR, USA) was used primarily for informational purposes and to provide a broader perspective. In the case of chromium, 45.45% of the samples exceeded the permissible levels, with concentrations ranging from 106 mg/kg to 186 mg/kg, the highest value being nearly twice the alert threshold. Notably, not all protected areas maintain contaminant levels within safe limits. The sample from the Mârzești Forest protected site revealed considerably raised concentrations of mercury, arsenic, and lead, exceeding the alert thresholds (1 mg/kg—mercury, 15 mg/kg—arsenic, and 50 mg/kg—lead) established through Order no. 756/1997 issued by the Minister of Water, Forests, and Environmental Protection from Romania. On the other hand, the sample from Podu Iloaiei, an area with intensive agricultural activity, shows contamination with mercury and cadmium, highlighting significant anthropogenic pollution. The findings of this study are expected to raise public awareness regarding soil pollution levels, particularly in densely populated regions and protected ecological zones. Moreover, the results provide a scientific basis for policymakers and relevant authorities to implement targeted measures to manage soil contamination and ensure long-term environmental sustainability. Full article

In both fundamental and applied scientific exploration, nanostructured protective materials have garnered substantial interest owing to their multifaceted utilization in the fields of medicine, pharmaceuticals, and electronics, among others. This study investigated the evolution of cutting-edge materials for electromagnetic radiation attenuation, with a specific emphasis on the incorporation of superparamagnetic magnetite nanoparticles, Fe₃O₄, into composite systems. The nanoparticles were generated through chemical condensation, meticulously adjusting the proportions of iron salts, specifically FeSO₄·7H₂O and FeCl₃·6H₂O, in conjunction with a 25% aqueous solution of ammonia, NH₄OH·H₂O. This study examined the intricate details of the crystalline structure, the precise composition of phases, and the intricate physicochemical attributes of these synthesized Fe₃O₄ nanoparticles. The analysis was conducted employing a suite of advanced techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive analysis (EDAX). The key findings of this research suggest that the magnetic nanoparticles generated through chemical condensation have an average size between 10 and 11 nm. This size was determined using BET surface area measurements, which were precise to within 0.1 nm. Moreover, this study demonstrated that incorporating superparamagnetic nanoparticles into composite materials significantly reduces microwave radiation. In particular, an optimal concentration of 0.25% by weight leads to a maximum decrease of 21.7 dB in cement specimens measuring 10 mm in thickness. Moreover, a critical threshold concentration of 0.5 weight percent is established, beyond which the interactions of nanoparticles inhibit the process of remagnetization. These investigations demonstrate that it is feasible to pursue a route towards the development of highly effective electromagnetic shielding materials tailored to specific requirements for diverse applications. Full article

Background: The durability of computer-aided design/computer-aided manufacturing (CAD/CAM) resin nanoceramics in the oral environment is influenced by aging factors such as thermocycling and ultraviolet (UV) exposure. This study investigates the impact of these aging processes on surface characteristics and repair bond strength. Methods: CAD/CAM resin nanoceramic samples were divided into the following five groups: control (non-aged), 1-year and 5-year thermocycling, and 1-year and 5-year UV aging (n = 12). For the thermocycling procedure, the parameters employed were a temperature range of 5–55 °C with dwell times of 20 s per bath and 10,000 and 50,000 cycles; for the ultraviolet aging process, the parameters were established at a wavelength of 340 nm, an intensity of 0.55 W/m², and durations of 300 h and 1500 h. Surface roughness, microhardness, and repair bond strength were analyzed through profilometry, Vickers microhardness testing, and shear bond strength assessment, respectively. SEM, AFM, and XRD analyses were performed for structural evaluation. Results: Both thermocycling and UV aging significantly increased surface roughness (p < 0.001) while reducing microhardness and repair bond strength (p < 0.001). UV aging had a more pronounced effect, particularly after five years, leading to the highest surface roughness (Ra: 61.77 μm; Rz: 271.57 μm) and lowest microhardness properties (63.13). EDAX analysis indicated matrix degradation and an increase in inorganic filler exposure. Conclusions: Aging significantly affects the surface characteristics of CAD/CAM resin nanoceramics, with UV aging exhibiting the most detrimental impact. These findings highlight the necessity of considering long-term material stability in dentistry. Full article

Cobalt–chromium (CoCr) alloys are frequently used to produce customized dental applications such as crowns, bridges, or prostheses. These medical products have anatomical forms, and can be effectively manufactured using the laser-based powder bed fusion (PBF-LB/M) technique. A major disadvantage of this approach is the extended time required to refine the resultant surface. The purpose of this research is to reduce the surface roughness of PBF-LB/M/CoCr dental crowns by adopting drag finishing (DF) technology. To evaluate the impact of this automatic post-processing, surface roughness measurements and geometrical investigations were undertaken. The microstructure was characterized using scanning electron microscopy (SEM), and the chemical composition was verified by energy-dispersive X-ray spectroscopy (EDAX). On outside surfaces, the DF post-processing decreased the initial surface roughness by 70–90%. The dental crown’s surface roughness value after DF post-processing was comparable to that of the basic form (cylinder). The lowest roughness was obtained with DF3 post-processing (Ra~0.60 μm). The inner surfaces were limitedly finished. The 3D surface texture showed that the DF method reduced the height of peaks, uniformizing the surfaces. CMM work compared the deviations between the virtual model and the printed samples before and after DF post-processing. This analysis revealed that dimensional deviations were reduced on the outside crown walls, ranging from +0.01 to +0.05 mm. The laser parameters and the heat treatment applied increased the hardness of CoCr crowns to 520 HV, but the proper DF conditions identified reduced the surface roughness and improved the accuracy. Full article

Despite the widespread use of Mg and Al alloys among light metals in the automobile and aviation industries, they have low tensile and fatigue strength. Therefore, in the present work, AZ91 Mg and AA6063 Al alloys were coated with a multilayer transition metal nitride film (Cr/CrN/TiCrN/TiCrCN) to increase fatigue and tensile strength. Films with Cr/CrN/TiCrN/TiCrCN microstructure architecture were synthesized on the surfaces of AZ91 Mg and AA6063 Al alloys using the CFUBMS (closed-field unbalanced magnetron sputtering) system, one of the PVD (physical vapor deposition) techniques. Films’ structural properties were analyzed by XRD, SEM, and EDAX, whereas mechanical properties were investigated using tensile and rotary bending fatigue testing machines. According to the SEM examination, the Cr, CrN, TiCrN, and TiCrCN multilayer nitride films on the two alloys have a columnar and dense microstructure. The XRD analysis detected Cr (211), CrN (111) and (200), TiN (111), (200) and (222), and TiCN (200) and (311) diffraction peaks. The Cr/CrN/TiCrN/TiCrCN multilayer coating increased the fatigue limit value of AZ91 by 11.22% from 70.26 MPa to 78.15 MPa. The fatigue limit value of AA6063 decreased by 9.79% from 79.71 MPa to 71.9 MPa. After coating, the tensile strength value of AZ91 increased from 137.89 MPa to 139.65 MPa, while the tensile strength of AA6063 decreased from 129.35 MPa to 118.16 MPa. Full article

The concept of the sustainable development of the world economy is currently aimed at achieving carbon neutrality, and this is due to the global warming of the planet. Energy and construction make a significant contribution to the release of carbon emissions into the environment and atmosphere. According to statistics, simply burning one ton of Portland cement clinker provokes the release of at least half a ton of carbon dioxide. In this study, the prepared samples were subjected to electron diffraction studies, as well as the X-ray phase analysis of the zone (XRF) using an ARLX’TRA diffractometer. Studies of macro- and microstructures were carried out using a Quanta 3D 200i scanning microscope. The obtained spectra were processed using EDAX TEAM software. The study of the microstructure of the samples showed that the bulk of the heterogeneous systems consisted of volumetric aggregates and intergrowths, i.e., small accumulations on their surfaces with pronounced cleavage, features of the microstructure indicating mineral formation processes. Therefore, the development of low-carbon construction models will make it possible to make a contribution and open an effective path to the implementation of climate policy through the rational use of natural resources and the involvement of industrial waste and nature-like technologies in the production process. In this regard, one of the options for solving the identified problems is to revise existing technologies and develop low-carbon, low-clinker binders using industrial waste and substandard raw materials. Full article