Iranian Journal of Science and Technology, Transactions A: Science最新文献

Water pollution, exacerbated by industrialization and agricultural practices, necessitates effective and sustainable treatment solutions. Conventional wastewater treatment methods often fall short due to high costs and inefficiencies. Nanotechnology, particularly copper-based nanoparticles (Cu and CuO NPs), has emerged as a promising alternative due to their high surface area, catalytic properties, and antimicrobial effects. This study explores the biosynthesis of Cu and CuO NPs using Citrus aurantium extract and evaluates their efficiency in removing Congo Red dye from wastewater. Cu and CuO NPs were synthesized using an aqueous extract of Citrus aurantium as a reducing and stabilizing agent. Characterization was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), zeta potential measurements, and Brunauer-Emmett-Teller (BET) surface area analysis. The dye removal efficiency was assessed using spectrophotometry, and adsorption behavior was analyzed through isotherm models and kinetic studies under varying experimental conditions. XRD confirmed the formation of crystalline Cu and CuO NPs. SEM images revealed aggregation, while FTIR confirmed organic capping agents. CuO NPs exhibited a higher surface area (7.34 m²/g) than Cu NPs (3.19 m²/g), leading to superior initial dye removal efficiency. Adsorption followed the pseudo-second-order kinetic model and was thermodynamically favorable. This study demonstrates the potential of Citrus aurantium-derived Cu and CuO NPs as eco-friendly and effective agents for wastewater treatment. CuO NPs excel in single-use applications, whereas Cu NPs offer better stability over multiple reuse cycles, providing a sustainable approach for environmental remediation.

In this work, we introduce the concept of statistical deferred weighted convergence for double real sequences and use it to establish a Korovkin-type approximation theorem on double sequences of positive linear operators. These operators act on the space of (2pi)-periodic, continuous real-valued functions in two dimensions. We also demonstrate that our results are more robust than those obtained from their single-sequence statistical and classical counterparts. Furthermore, we examine the rates of statistical deferred weighted convergence with the same set of (2pi)-periodic functions. Finally, we provide several examples to validate our theoretical findings and present suitable graphs via MATLAB software to demonstrate the convergence behaviour of the results under our proposed methods.

The properties and applications of Ferric Chloride (FeCl₃) and Aluminum Chloride (AlCl₃) films made by the sol–gel technique are fully examined in this work. Its main objectives are these films’ synthesis, structural characterization, and performance assessment. Using a sol–gel dip-coating process, thin films of pure indium tin oxide (ITO) and ITO mixed with FeCl₃ and AlCl₃ at ratios of 50, 100, and 150% were produced. Indium (III) Chloride (InCl₃) and Trichlorostannate (SnCl₄) two reasonably priced precursors were used. X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), and ultraviolet–visible UV–Vis spectroscopy were utilized to examine the ITO samples. Whereas the gap in the optical band of pure ITO was 4.49 eV, the energy gaps for ITO mixed with FeCl₃ at 50, 100, and 150% were 2.61, 2.89, and 2.35 eV, respectively. The energy gaps for ITO combined with AlCl₃ at the same ratios were 1.73, 1.83, and 1.5 eV. In the XRD patterns of indium oxide, the (222) plane showed a large peak, signifying a high degree of crystallinity. Using AFM images, the average grain size of pure ITO was discovered to be 61 nm. The average grain sizes for AlCl₃ were 17, 21, and 68 nm, whereas the average grain sizes for FeCl₃ were 96, 36, and 178 nm at 50, 100, and 150% ratios, respectively. The FeCl₃-doped films’ average particle sizes were found to be 23.87, 41.12, and 36.27 nm, respectively, according to SEM images. The AlCl₃-doped films’ average particle sizes were 45.47, 42.72, and 35.25 nm. The water contact angles for FeCl₃ films were found to be 32.57° for pure FeCl₃ and 18.74°, 73.66°, and 43.98° for FeCl₃ at 50, 100, and 150% mixing ratios, respectively, according to the contact angle measurements. The water contact angles for AlCl₃ films were 65.39°, 85.99°, and 78.12° for 50, 100, and 150% of the mixing ratio, in that order.

The article is aimed at computer modeling of giant magnetic resistance in thin antiferromagnetic films in an external magnetic field. Computer simulation uses the Monte Carlo method and Ising antiferromagnetic model to describe the magnetic properties of the film. Metropolis’ algorithm forms the spin states of the film. The semi-classical model describes the movement of electrons through the crystal lattice of the film. The electron participates in chaotic thermal motion and drift under the influence of an electric field. The external magnetic field creates magnetization in the antiferromagnetic film. The magnetic moment of the film affects the movement of electrons through the exchange interaction between the spins of atoms and electrons. The simulated system includes a non-magnetic conductive film and an antiferromagnetic film. The spinpolarized electric current is injected through a non-magnetic film. Simulations showed two mechanisms for electrical resistance growth. The first mechanism is associated with electron filtration at the interface between the non-magnetic film and the antiferromagnetic film. The second mechanism is associated with the formation of domains acting as impurities and leading to electron scattering. These two mechanisms give maximum resistance at different magnetic field strengths. The addition of these two mechanisms gives a nonlinear law of magnetoresistance growth as the magnetic field increases.

We rely on the Carleman estimate and some functional analysis tools to establish a stability result with a logarithmic estimate for an inverse problem governed by the biharmonic equation in a smooth 2D domain (Omega ). The inverse problem under consideration consists of recovering Robin’s coefficients on a part (Gamma ) of the boundary from a single boundary measurement on the remaining part (gamma ) of that boundary. Such inverse problems are usually motivated by the detection of specified functions in beam deflection. The stability result is supported by a numerical example.

In this paper, the sol–gel method is used to synthesize the BaGd_xTi_1-xO_3-x/2□x/2 samples with x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05. X-ray diffraction (XRD), spectroscopy Raman, scanning electron microscopy (SEM), and spectroscopy UV–visible have been employed to characterize the structure and morphology of the as-prepared samples. X-ray diffraction analysis indicated the formation of a tetragonal structure with the detection of pyrochlores phases with small intensity. Raman spectroscopy reveals the coexistence of bands characteristic of the tetragonal phase. SEM and EDS images demonstrate that the distribution of the grain is spherical with lower density and the average grain size of BGxT ceramics changes with the increase in Gd content. The UV–VIS spectra of samples were applied in the 200 to 900 nm spectral range and show that the transmittance values are about 60 and 80 and the absorbance values are lower than 12%. The dielectric properties as a function of temperature and as a function of frequency are also studied and show a decrease progressively in the dielectric constant with an increase in the Gd ratio.

The ¹⁷O (p, γ)¹⁸F radiative capture reaction, a key driver of stellar nucleosynthesis, is comprehensively investigated at astrophysically relevant energies using a sophisticated theoretical approach. The Woods-Saxon potential model is employed to accurately deduce the cross-section for this reaction, which is essential for modeling hydrogen burning and isotope synthesis in stars. The calculated astrophysical S factor, a critical parameter for analyzing such reactions, exhibits excellent agreement with available experimental data and predictions from other models. Moreover, the electric dipole (E1) transition strength, governing the astrophysical S factor, is computed within the 0-500 keV energy range. Extrapolation of the S factor to zero center-of-mass energy yields a value of 4.807keV.b for the dominant E1 transition through the ¹⁸F (1 excited state to the ground state (1⁺), consistent with previous studies. To investigate correlated transitions, calculations of S (0) values have been performed for excited state transitions, specifically from the (1⁻) state to the (2⁺) state, the 1⁻state to the 3⁺ state, and the (1⁻) state to the 1⁺ state. Additionally, S factor for E2 transitions have also been calculated. These results provide invaluable nuclear data inputs for modeling stellar nucleosynthesis processes.

A bounded linear operator T on a Hilbert space H is said to be orbital frame if there exists a vector (x in H) such that orb(T, x) is a frame. This paper presents a new examination of frames in the context of Hilbert spaces, showing that orbital frames operators must be Fredholm. In particular, if an orbital frame operator either has a dense range or be one-to-one then it is an invertible.

The present research study evaluated the effects of benzylaminopurine (BAP) in combination with naphthalene acetic acid (NAA), as well as methyl jasmonate and nano-sized TiO₂ elicitors on callus induction, pharmaceutically important flavones and rosmarinic acid in leaf-derived calli of Teucrium polium. The feed-forward Artificial Neural Network (ANN) model was also applied to predict the effects of hormones and elicitors on phenolic compounds production. The best callus induction was achieved with media fortified with 1.5 mg L^− 1 BAP plus 0.5 mg L^− 1 NAA, followed by 1.5 mg L^− 1 BAP. Biochemical features and rosmarinic acid have substantially raised by the maximum ones in calli elicited with methyl jasmonate (50 µM). The exception was phenolic acids possessed much greater content in 10 mgL^− 1 nano-sized TiO₂-treated calli. High antioxidant activities (IC₅₀ 2.066 ± 0.24 µg mL^− 1 and 383.79 ± 33.60 mg Fe^+ 2 100 g^− 1 DW), with approximately 2- and 1.5-fold increases compared to controls, were observed in hydromethanolic extracts of calli elicited by 50 µM methyl jasmonate on an MS medium containing 1.5 mg L^− 1 BAP plus 0.5 mg L^− 1 NAA. Likewise, the highest contents of anti-genotoxic flavones apigenin and luteolin were measured in callus pretreated with 50 µM methyl jasmonate on the media supplemented with 1 mg L^− 1 BAP (180.67 ± 2.52 and 201.11 ± 3.63 µg100 g^− 1 extract, respectively) and 1.5 mg L^− 1 BAP plus 0.5 mg L^− 1 NAA (206.01 ± 7 and 256.22 ± 2.1 µg 100 g^− 1 extract, respectively). The ANN with hyperbolic-tangent (10-1-3) activation function (r² 0.99, SSE 0.01, and RE 0.001) showed a strong correlation between the ANN model outputs and the experimental amounts of polyphenols, ortho-diphenols, and phenolic acids.

The occupational hazard of coal mine dust not only poses a serious threat to miners’ health but also gives rise to various social issues. Considering the significance of group dynamics (GD), this study presents a driving framework for collaborative prevention and control of dust (CPCD) in miners, encompassing the internal force field (IFF), situational force field (SFF), and GD. Through qualitative analysis, the relationships among these driving elements are examined using statistical analysis methods and corresponding tests and corrections conducted on a dataset comprising 1055 samples. The empirical analysis reveals the following: (1) There is a moderate to strong correlation between CPCD and GD, SFF, and IFF. (2) The SFF, IFF, and GD significantly predict CPCD. (3) GD acts as a significant mediator between IFF and CPCD, and The IFF influences CPCD through GD. (4) The SFF positively regulates the impact of IFF on GD. By delving into miners’ participation behavior and gaining a contextualized understanding of collaborative prevention and control of dust, this research provides theoretical and empirical references for individual miners, coal mine enterprises, and governments to mitigate and manage occupational hazards related to dust effectively.