Babol Noshirvani University of Technology

In this research, achieving the results of existence and stability for two classes of q q ‐fractional differential, in the first step, a nonhybrid equations under nonhybrid, integro, multiterm–point‐strip type conditions and in the second step, a hybrid integro inclusions, is of interest to the authors. To do these aims, some techniques and nonlinear theorems such as the Kuratowski measures based on the Sadovskii's theorem, Krasnoselskii–Zabreiko criterion, and Dhage's technique are used. We generalize the Gronwall inequality in relation to q q ‐fractional differential nonhybrid equation with integro, multiterm–point‐strip conditions. Further, the two cases of stabilities criteria have been taken into account. To examine the correctness of the outcomes, we provide some illustrative applications along with conclusion at the end.

In this article, a new mathematical modeling is introduced for analyzing the free vibrations of a laminated composite curved beam (LCCB) with arbitrary layups. To achieve this, in‐plane and out‐of‐plane deformations, shear deformations, rotary inertia, warping effect, Poisson's effect, and coupling of tension‐bending‐torsion are considered. Using the analytical and finite element methods, the system's discrete equations are derived in matrix form. By solving these equations, the free vibration characteristics of the beam are calculated. The computed results are compared with those of specific cases presented by other researchers, as well as with results obtained from a three‐dimensional ANSYS software, showing very good agreement. Furthermore, the effects of various parameters on the vibrational behavior of the curved beam are investigated in detail.

The Night Light Satellite (DMSP-OLS) collects data on artificial lights emitted from Earth's surface at night. With a long-term dataset spanning 20 years, its data remains widely utilized. However, variations in sensor types, flight conditions, and the absence of internal calibration have caused significant fluctuations in digital values within the same year. To address this issue, researchers have developed models to enhance image comparability. One key solution is intermediate calibration, which in this study is categorized into two main approaches: fixed reference area methods and stable pixel methods. This study evaluates existing calibration techniques and their effectiveness over a 20-year period in the Tehran metropolitan area, with an SNDI of 9.66, using 20 models, 13 based on fixed reference area methods and 7 on stable pixel methods. These models were selected based on prior research and the study's primary objectives. Key accuracy assessment criteria include the visual evaluation of line plot convergence, reduction in SNDI values, and alignment with GDP data. Among the fixed reference area models, the most effective approaches involve using the Sicilian reference area and the F18 satellite (2010) with quadratic regression, achieving an SNDI value of 9.09 and a correlation coefficient of 0.93 with GDP. For stable pixel methods, the best-performing model removes outlier bright pixels and applies quadratic regression, resulting in an SNDI value of 9.06 and a correlation coefficient of 0.94 with GDP. When comparing these two leading approaches, both provide similar accuracy; however, fixed reference area methods are simpler to implement, whereas stable pixel methods are more automated and minimize operator error. The choice of the most suitable calibration method depends on the study’s objectives, available resources, spatial scale, and the socio-economic characteristics of the region.

Copper matrix composites reinforced with tungsten particles were fabricated via submerged friction stir processing (FSP) using both rolled and annealed copper sheets to investigate the effect of tool traverse speed and initial microstructure on particle distribution, microstructure evolution, and material properties. Optimal particle distribution and the finest equiaxed grain structure (4.8 ± 0.5 µm) were achieved in the 800–20-R condition, attributed to the high strain rate (31.9 s⁻1), peak temperature (449 °C), and a high Zener-Hollomon parameter. In contrast, annealed samples showed improved particle dispersion only at higher traverse speeds, with sample 800–80-O exhibiting refined grains (8.1 ± 1.2 µm) and reduced agglomeration. Mechanical testing showed the highest hardness (107.4 ± 9.1 HV), ultimate tensile strength (314.5 ± 12.5 MPa), and toughness (85.2 ± 1.2 MJ/m3) in the 800–20-R sample due to uniform W dispersion and grain refinement. Electrical conductivity was also highest in this condition (71.3 ± 1.3% IACS), though still lower than annealed base copper (99.2 ± 1.5% IACS), indicating a trade-off between reinforcement and conductivity.

This study investigates the effects of process parameters and initial strain conditions on the microstructural, mechanical, and electrical properties of tungsten particle‐reinforced copper composites fabricated via friction stir processing (FSP). Composites produced from annealed sheets demonstrate greater nonuniformity due to chaotic material flow, while those made from rolled sheets exhibit declining uniformity as the traverse speed increases. Hardness values ranging from 56.3 ± 1.6 to 130.3 ± 2.2 HV are influenced by the initial sheet condition, tungsten particle dispersion, and grain structure. The highest tensile strength (281.2 ± 13.1 MPa) and toughness (86.7 ± 1.4 MJ m⁻³) are observed in composites fabricated from rolled sheets at a rotational speed of 800 rpm and a traverse speed of 20 mm min⁻¹, attributed to uniform tungsten distribution and refined grain structure. Electrical conductivity in the Cu–W composites varies between 61.8 ± 1.2% IACS and 87.6 ± 1.1% IACS. The work‐hardening effects in the rolled base metal reduce its conductivity to 85.3 ± 1.3% IACS, while FSP slightly enhances conductivity in composites made from rolled sheets, achieving 87.6 ± 1.1% IACS. In contrast, composites produced from annealed sheets experience further reductions in conductivity due to tungsten particle agglomeration and grain refinement.

The urgent situation during the COVID-19 pandemic led to uncertainty in COVID-19 statistics, such as infection rate, Hospitalization Rate (HR), and Death Rate (DR). This paper addresses the challenge of causal forecasting of COVID-19 severity measures while considering the uncertainty utilizing the Adaptive Neuro-Fuzzy Inference System (ANFIS). The causal and time series ANFIS forecasters are developed through PYTHON coding in the case study of Iran using a daily dataset of 1010 entries collected from 2020 to 2022. The results demonstrate the superiority of causal ANFIS forecasters according to accuracy measures of the training, test, and overall data sets. The accuracy of 96.9% and 99.3% for causal ANFIS forecasters of HR and DR, respectively, demonstrates the considerable capability of the created forecasters to provide accurate forecasts of COVID-19 severity measures. In addition, causal ANFIS forecasters provide the opportunity for accuracy sensitivity analysis according to the one-factor-at-a-time exclusion of indicators. The corresponding results reveal that although the vaccination rate is a significant indicator, infection and hospitalization rates are the most important indicators affecting the accuracy of causal ANFIS forecasters of HR and DR, respectively.

This study investigates the flow characteristics of a two-dimensional (2D), steady-state, magnetohydrodynamic (MHD) hyperbolic tangent nanofluid using a hybrid analytical and numerical (HAN) approach over a porous, permeable wedge. Its flexibility lies in leveraging various numerical methods, making it a robust tool compared to other semi-analytical techniques. In industrial applications, such non-Newtonian fluids, including hyperbolic tangent fluids, MHD models, and nanofluids, are frequently encountered, particularly in scenarios involving radiation and magnetic fields. The research emphasizes the equations of energy, concentration, momentum, and continuity, which are transformed into a set of nonlinear, third-order coupled ordinary differential equations (ODEs) through similarity transformations. These ODEs are characterized by 11 key dimensionless parameters: the Lewis number (0.1–1), Prandtl number (0.5–4), Brownian diffusion (1–9), thermophoresis parameter (1–9), Dufour number (0 –4), Soret number (−1 to −5), and thermal radiation parameter (2–10). The study’s primary objective – and its most notable novelty – is to explore the parameters that influence both temperature and concentration distributions. It further examines the effect of these parameters on the Sherwood number, Nusselt number, and skin friction coefficient. Results indicate that the Prandtl number significantly reduces velocity while increasing fluid temperature, whereas Dufour and Soret numbers minimally affect velocity but increase concentration levels. Factors such as thermophoresis, Brownian diffusion, and thermal radiation markedly elevate temperature and concentration averages, while parameters like the Weissenberg number, power law index, wedge angle, and medium permeability show negligible impact.

The purpose of this study is to explore the potential of using waste tire rubber ash (TRA) as a substitute for a portion of cement in structural concrete. In this research, five different mixing designs were selected, varying the percentage of TRA replacing cement. The percentages included 0% (control concrete), 2.5%, 5.0%, 7.5%, and 10.0%. The results from tests conducted on reinforced concrete beam samples containing 10% rubber ash were compared with those of the control samples. The findings indicated that the compressive strength increased by up to 18%, while the bending strength improved by up to 14%. Additionally, the monotonic behavior of the reinforced concrete beams demonstrated significant enhancement. Cyclic tests on the reinforced concrete samples with 10% TRA substitution revealed an increase in energy dissipation capacity of up to 23% and an improvement in the viscous damping ratio of up to 16%. These studies suggest that replacing certain amounts of TRA with cement can enhance the performance of concrete.

This study explores the strategic synthesis of sulfonated polyethersulfone (SPES) with tunable sulfonation degrees to engineer selective interfacial layers (SLs) for thin‐film composite (TFC) forward osmosis (FO) membranes. To overcome the persistent trade‐off between water permeability and salt rejection in conventional TFC membranes, this work introduces an interlayer engineering strategy utilizing zeolitic imidazolate framework‐8 nanoparticles (ZIF‐8 NPs). Unlike traditional approaches that focus solely on membrane surface modification, the integration of ZIF‐8 as a nanostructured interlayer addresses interfacial defects and enhances solute screening by leveraging its molecular sieving capabilities and hydrophilicity through the Janus membrane effect. SPES‐based membranes exhibited a notable enhancement for water flux from 15.23 to 32.12 L/m² h compared to neat polyethersulfone (PES) SLs. Simultaneously, the salt rejection effectively reached 93.9% for SPES/ZIF‐8/PA(#2). XRD and FTIR analyses confirmed the crystallinity and chemical integrity of ZIF‐8 NPs, while FESEM revealed their uniform dispersion across the SL surface. Notably, the sulfonation process not only enhanced surface porosity but also created a chemically reactive interface for ZIF‐8 anchoring, a dual‐functionality rarely achieved in prior studies. The findings offer a scalable framework for designing high‐performance TFC membranes with hierarchically engineered interfaces, paving the way for next‐generation desalination and resource recovery systems.

Effective wound care and infection prevention are critical for optimal wound healing. Recent advancements in tissue engineering have focused on developing nanofiber scaffolds using biopolymers, which mimic the natural extracellular matrix and offer enhanced healing properties. This study investigates the fabrication of nanofiber scaffolds composed of elastin protein and polyvinyl alcohol (PVA) via electrospinning, with honey incorporated for its antibacterial and anti-inflammatory benefits. Field Emission Scanning Electron Microscopy (FESEM) analysis revealed uniform, interconnected, bead-free fibers with diameters ranging from 365 to 435 nm. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of elastin and honey in the nanofibers. The scaffolds exhibited mechanical properties within the range of human skin, indicating their suitability for wound protection. Water vapor permeability (WVTR) tests showed values ranging from 400.2 to 413.08 g/m²/day, ensuring proper gas exchange and maintaining a humid environment conducive to healing. The PVA/elastin/honey (PVA/EL/H) nanofibrous mats displayed exceptional antibacterial activity against Gram-positive and Gram-negative bacteria. In vivo studies on rat models provided further evidence for the therapeutic potential of PVA/EL/H dressing with the wound closure rate of 89.17% by day fourteen. Overall, the PVA/EL/H nanofibrous mats are a promising candidate for next-generation wound care solutions due to their combined effective antibacterial activity, and improved wound healing outcomes.

In this study, the micromechanical damage of polymer composites under thermal fatigue loading in cryogenic conditions is investigated using micromechanical numerical analysis. The widespread use of polymer composites in structures such as multi‐layer tanks for storing compressed gases in the food, medical, nuclear, and aerospace industries highlights the importance of analyzing mechanical property degradation and damage under cryogenic conditions. In this research, thermal fatigue loading is applied to an RVE model of carbon fiber‐reinforced polymer composite to examine mechanical property degradation and damage modes. The results show significant agreement with previous experimental studies. The findings indicate that fiber‐matrix debonding and matrix cracking are the dominant damage modes under cryogenic conditions. Moreover, short‐term fatigue cycles have approximately 40% more impact on the degradation of mechanical properties compared to long‐term cycles. Additionally, fatigue analysis reveals that more than 50% of the mechanical property degradation occurs during the initial fatigue cycles, with negligible changes in the later cycles. Highlights Micromechanical damage analysis of polymer composites under cryogenic thermal fatigue loading. Fiber‐matrix debonding and matrix cracking are identified as primary damage modes in cryogenic conditions. Numerical simulation results show significant agreement with experimental studies. Short‐term fatigue cycles cause more pronounced mechanical property degradation than long‐term cycles. Initial fatigue cycles account for the majority of damage, with negligible changes in later cycles.

This paper analyzed the simultaneous transfer of matter and thermal energy in the hydrodynamic movement of a micropolar liquid across an expanding surface, taking into account both the effects of viscosity loss and chemical interactions under the influence of a magnetic field. The finite element approach has been applied to scrutinize the permeation of important flow variables on the flow repartition functions. Another approach was an analytical solution using the Akbari‐Ganji method named AGM. This study analyzed key factors that influence velocities, concentration, temperatures, and microrotation functions. The results show that all functions except temperature are inversely affected by the micropolar factor. In contrast, as a result of the micro rotational parameter, the temperature and concentration function go up while the speed goes down. The higher values of the Eckert number lead to higher temperatures and lower concentrations, which are amplified by the Schmidt number. The numerical method (Runge–Kutte 4th) was used as a benchmark to evaluate the accuracy, efficiency, and simplicity results.

This study presents an elastic one-dimensional numerical model to simulate the filling process of a large-scale, partially drained pipeline with an undulating profile, incorporating bypass systems. The model uses the Method of Characteristics to solve water hammer equations and integrates the Discrete Gas Cavity Model to capture column separation effects. Validation is performed using two experimental test rigs and comparisons with existing numerical models, showing RMSE values between 1.06 and 7.95. The results highlight three key findings: (1) oversized bypasses generate severe transient pressures; (2) effective air management enables higher filling flow rates, significantly reducing filling time; and (3) bypass lines help dampen pressure fluctuations, with a notable drop in ∆H from 528 m to 6.8 m occurring in stage b, following the release of trapped air. Additionally, this study challenges the practicality of the AWWA’s recommended pipeline filling velocity limit of 0.3 m/s, showing that strict adherence to this guideline is often unrealistic for large-scale systems. Overall, the findings emphasize the need for a balanced design approach that reduces transient risks while maintaining operational efficiency in large-scale pipelines.

This study investigates the impact of varying deposition voltages on the morphology, roughness, thickness, and functional properties of zinc oxide (ZnO) coatings on titanium substrates. Using SEM analysis, it was observed that at lower voltages (1.5–2 V), ZnO coatings exhibit a flake-like morphology, transitioning to complex flower-like structures at higher voltages (2.5–3 V). Surface roughness initially increases with voltage, peaking at 2.5 V (1.98 ± 0.54 µm) before decreasing slightly at 3 V due to grain coalescence. Coating thickness consistently increases with voltage, reaching 32.4 ± 0.2 µm at 3 V, driven by faster ion migration and enhanced deposition rates. Wettability measurements showed a shift from hydrophobic to hydrophilic behavior as the voltage increased from 2.5 V (96.0° contact angle) to 3 V (24.6° contact angle), suggesting a change in surface texture and densification. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests confirmed that higher voltage coatings offer improved corrosion resistance, with the sample coated at 3 V exhibiting the best performance (corrosion rate of 1.654 ± 0.012 µm/year). This enhancement is attributed to the denser and less porous nature of the coating, which reduces pathways for corrosive agents.

Given a set of disks in the plane, the goal of the problem studied in this paper is to choose a subset of these disks such that none of its members contains the centre of any other. Each disk not in this subset must be merged with one of its nearby disks that is, increasing the latter’s radius. This problem has applications in labelling rotating maps and in visualizing the distribution of entities in static maps. We prove that this problem is NP-hard. We also present an ILP formulation for this problem, and a polynomial-time algorithm for the special case in which the centres of all disks are on a line.

Cervical cancer is, to date, the second most common cause of cancer in female patients worldwide. Most of the present-day research activities have concentrated on studies of antitumor medicinal plants and bioactive compounds obtained from natural flavonoids such as quercetin (Q), naringin (N), and rutin (R). The present study reported an in vitro method for assessing the combined anticancer activity of quercetin, naringin, and rutin in combination in HeLa cervical cancer cells. The anticancer potential of the compounds was investigated via experiments involving apoptosis, detection of ROS levels, rhodamine 123 staining, AO/EtBr staining, scratch tests, real-time methods, and Western blot techniques in protein-mediated autophagy pathways. On the basis of the results from the MTT assay and combination index, reasonable combinations of RQ and RQN were selected. Experiments revealed significant upregulation of Beclin1 protein levels and corresponding downregulation of P62, indicating enhanced autophagic flux in HeLa cells treated with flavonoid combinations. Assays for apoptosis revealed that the total number of apoptotic cells increased in a time-dependent manner, and the percentages of apoptotic cells enriched with the RQN combination were 16.07%, 65.02%, and 8.91% at 24, 48, and 72 h, respectively. The combination of RQ resulted in the following percentages of apoptotic cells at the same time points: 31.04%, 32.36%, and 11.46%. Real-time PCR and Western blotting of autophagy-related marker proteins revealed that the flavonoid combinations drastically modulated the autophagy pathway in HeLa cells by increasing the expression levels of Beclin1 (protein and expression levels) and LC3 (expression), whereas the expression level of P62 (protein and expression levels) notably decreased. Thus, these data suggest that flavonoid combinations may induce cervical cancer cell death through an autophagy-mediated mechanism and apoptosis. These flavonoid combinations represent potential therapeutic strategies for treating cervical cancer.

The main objective of this paper is to investigate the equivalence problem for fifth-order differential operators on the line. We specifically focus on the case where the differential operators are subjected to general fiber-preserving transformations. To tackle this problem, we employ the Cartan method of equivalence via direct equivalence problem. This method allows us to determine whether two given differential operators are equivalent or not under a certain transformation. By applying this method, we are able to establish the conditions under which two fifth-order differential operators are equivalent under general fiber-preserving transformations. This provides us with a comprehensive understanding of the equivalence problem for these operators on the line. Overall, this paper contributes to the field of differential equations by shedding light on the equivalence problem for fifth-order operators and providing a systematic approach to analyze their equivalence under general fiber-preserving transformations.

Collapsible soils pose significant geotechnical challenges due to their tendency to exhibit high strength under natural moisture conditions but undergo substantial settlement upon wetting. To address this issue, various stabilizing agents, including lime, cement, silicates, resins, and acids, have been explored. This study investigates the effectiveness of colloidal silica (CS), a low-viscosity solution capable of forming a gel, as a stabilizing agent. Its unique properties enable it to be injected into or mixed directly with soil, offering versatility in application. The behavior of CS-stabilized collapsible soil was evaluated through collapse potential and unconfined compressive strength (UCS) tests. Scanning electron microscopy (SEM) was also conducted to analyze microstructural changes in untreated and CS-treated soils. Colloidal silica was added at concentrations of 3, 5, 7, and 10% by weight of dry soil, with curing times of one, 7, 14, and 28 days. Collapse potential tests were performed at relative compactions of 80 and 85%, while UCS tests used a relative compaction of 95%. Results indicated that colloidal silica significantly reduced soil collapsibility while enhancing stiffness and UCS without inducing brittleness. A 5% CS concentration was optimal, reducing collapsibility from severe to negligible. Increased relative compaction (80 to 85%) further decreased collapsibility, whereas higher inundation stress increased it. These improvements are attributed to pore filling by colloidal silica, which enhances inter-particle bonding and structural integrity.

The utilization of lignin nanoparticles (LNPs) derived from black liquor, in combination with cinnamaldehyde (CI), shows great potential for the development of high-performance composite films in the food packaging industry. This study presents an approach for preparing LNPs from black liquor and integrating them with CI into starch (ST) films to produce active nanocomposite films with specific functionalities. Binary and ternary ST-based nanocomposites were prepared with varying weight percentages of LNPs (1, 3, and 5 wt%) and CI (3 and 5 wt%). Characterization of the resulting nanocomposites revealed significant improvements in physicochemical, morphological, thermal, mechanical, optical, antioxidant, and antimicrobial properties. The composite films exhibited a low water vapor transmission rate (WVP: 3.97 to 3.06 × 10− 10 g s− 1m− 1Pa− 1), reduced water solubility (WS: 53.00 to 19.76%), and enhanced mechanical strength (tensile strength: 3.66 to 5.15 MPa). The inclusion of LNPs also provided UV-blocking properties while maintaining visible light transmission and improved thermal stability. Morphological studies showed smooth surfaces without cracks or pores. Additionally, the composite films demonstrated antibacterial activity against S. aureus and E. coli, with enhanced efficacy in ternary-based nanocomposites. Overall, the combination of ST film with LNPs and CI shows promise for advanced functionalities in food packaging applications.