Search Results (1,175)

This study aims to clarify the nonlinear pressure loss patterns of the pneumatic system in a pneumatic seeder under varying pipeline structures and airflow parameters, and to develop a rapid prediction equation for the main pipe’s pressure loss. The studied multi-branch pipeline system consists of a main pipe, a header, and ten branch pipes. The main pipe is vertically installed at the center of the header in a straight-line configuration. The ten branch pipes are symmetrically and evenly spaced along the axial direction of the header, distributed on both sides of the main pipe. The outlet directions of the branch pipes are arranged in a 180° orientation opposite to the inlet direction of the main pipe, forming a symmetric multi-branch configuration. Firstly, this study investigated the flow characteristics within the multi-branch pipeline of the pneumatic system and elaborated on the mechanism of flow division in the pipeline. The key geometric factors affecting airflow were identified. Secondly, from a microscopic perspective, CFD simulations were employed to analyze the fundamental causes of pressure loss in the multi-branch pipeline system. Finally, from a macroscopic perspective, a dimensional analysis method was used to establish an empirical equation describing the relationship between the pressure loss (P) and several influencing factors, including the air density (ρ), air’s dynamic viscosity (μ), closed-end length of the header (Δl), branch pipe 1’s flow rate (Q), main pipe’s inner diameter (D), header’s inner diameter (γ), branch pipe’s inner diameter (d), and the spacing of the branch pipe (δ). The results of the bench tests indicate that when 0.0018 m³·s⁻¹ ≤ Q ≤ 0.0045 m³·s⁻¹, 0.0272 m < d ≤ 0.036 m, 0.225 m < δ ≤ 0.26 m, 0.057 m ≤ γ ≤ 0.0814 m, and 0.0426 m ≤ D ≤ 0.0536 m, the prediction accuracy of the empirical equation can be controlled within 10%. Therefore, the equation provides a reference for the structural design and optimization of pneumatic seeders’ multi-branch pipelines. Full article

This study aims to investigate the effects of phase synchronisation on tonal noise reduction in a multi-rotor UAV using an electronic phase-locking system. Experiments at the University of Bristol explored the impact of relative phase angle, propeller spacing, and blade geometry on acoustic performance, including psychoacoustic annoyance. Results show that increasing the phase angle consistently reduces the sound pressure level (SPL) due to destructive interference. For the two-bladed configuration, the highest noise reduction occurred at relative phase angle $\Delta \psi ={90}^{\circ }$, with a 19 dB decrease at the first blade-passing frequency (BPF). Propeller spacing had minimal impact when phase synchronisation was applied. The pitch-to-diameter ($P/D$) ratio also influenced results: for $P/D=0.55$, reductions ranged from 13–18 dB; and for $P/D=1.0$, reductions ranged from 10–20 dB. Maximum psychoacoustic annoyance was observed when propellers were in phase ($\Delta \psi =0^{\circ }$), while annoyance decreased with increasing phase angle, confirming the effectiveness of phase control for noise mitigation. For the five-bladed configuration, the highest reduction of 15 dB occurred at $\Delta \psi ={36}^{\circ }$, with annoyance levels also decreasing with phase offset. Full article

The alloy Pr₂Fe_16.75Ni_0.25 has been examined to investigate its structural properties, critical behavior, and magnetocaloric effects. Rietveld’s refinement of X-ray diffraction patterns has revealed a rhombohedral structure with an $R\overline{3}m$ space group. Pr₂Fe_16.9Ni_0.25 also demonstrates a direct magnetocaloric effect near room temperature, accompanied by a moderate magnetic entropy change ($-\mathrm{\Delta }{S}_M^{\max }$ = 5.5 J kg⁻¹ K⁻¹ at ${\mu }_0\mathrm{\Delta }H=5$ T) and a broad working temperature range. Furthermore, the Relative Cooling Power (RCP) is approximately 89% of the widely recognized gadolinium (Gd) for ${\mu }_0\mathrm{\Delta }H=2$ T. This compound exhibits a commendable magnetocaloric response, on par with or even surpassing that of numerous other intermetallic alloys. Critical behavior was analyzed using thermo-magnetic measurements, employing methods such as the modified Arrott plot, critical isotherm analysis, and Kouvel-Fisher techniques. The obtained critical exponents ($\beta$, $\gamma$, and $\delta$) exhibit similarities to those of the 3D-Ising model, characterized explicitly by intermediate range interactions. Full article

This paper investigates the initial-boundary value problem for a fourth-order pseudo-parabolic equation with a nonlocal source: $u_t+{\Delta }^{2}u-\Delta u_t={\left|u\right|}^{q-1}u-{\displaystyle \frac{1}{\left|\Omega \right|}}{\displaystyle {\int }_{\Omega }{\left|u\right|}^{q-1}udx}$. By employing the Galerkin method, the potential well method, and the construction of an energy functional, we establish threshold conditions for both the global existence and finite-time blow-up of solutions. Additionally, under the assumption of low initial energy $J\left(u_0\right)<d$, an upper bound for the blow-up time is derived. Full article

Experimental and theoretical studies were applied to investigate the adsorption properties of testagen (KEDG) peptide on copper surfaces in sodium chloride solution and, implicitly, its inhibition efficiency (IE) on metal corrosion. The tetrapeptide synthesized from the amino acids lysine (Lys), glutamic acid (Glu), aspartic acid (Asp), and glycine (Gly), named as H-Lys-Glu-Asp-Gly-OH, achieved an inhibition efficiency of around 86% calculated from electrochemical measurements, making KEDG a promising new copper corrosion inhibitor. The experimental data were best fitted to the Freundlich adsorption isotherm. The standard free energy of adsorption ($\mathsf{\Delta }{\mathrm{G}}_{\mathrm{a}\mathrm{d}\mathrm{s}}^{\mathrm{o}}$) reached the value of −30.86 kJ mol⁻¹, which revealed a mixed action mechanism of tetrapeptide, namely, chemical and physical spontaneous adsorption. The copper surface characterization was performed using optical microscopy and SEM/EDS analysis. In the KEDG presence, post-corrosion, SEM images showed a network surface morphology including microdeposits with an acicular appearance, and EDS analysis highlighted an upper surface layer consisting of KEDG, sodium chloride, and copper corrosion compounds. The computational study based on DFT and Monte Carlo simulation confirmed the experimental results and concluded that the spontaneous adsorption equilibrium establishment was the consequence of the contribution of noncovalent (electrostatic, van der Waals) interactions and covalent bonds. Full article

In this paper, we delve into the following nonlinear fractional Kirchhoff-type problem ${(a+b||(-\Delta )}^{{\displaystyle \frac{s}{2}}}{u\left|\right|}_2^2{)(-\Delta )}^{s}u+\lambda u=g\left(u\right)+{\left|u\right|}^{2_s^{*}-2}u$ in ${\mathbb{R}}^3$ with prescribed mass ${\int }_{{\mathbb{R}}^3}{\left|u\right|}^{2}dx=\rho >0,$ where $s\in ({\displaystyle \frac{3}{4}},1),\lambda \in \mathbb{R},2_s^{*}={\displaystyle \frac{6}{3-2s}}$. Under some general growth assumptions imposed on g, we employ minimization of the energy functional on the linear combination of Nehari and Poho$\breve{z}$aev constraints intersected with the closed ball in the $L^2\left({\mathbb{R}}^3\right)$ of radius $\rho$ to prove the existence of normalized ground state solutions to the equation. Moreover, we provide a detailed description for the asymptotic behavior of the ground state energy map. Full article

This study presents a comprehensive evaluation of starch-based gel formulations enriched with proteins and hydrocolloids for extrusion-based 3D food printing (3DFP). Food inks were prepared using corn or potato starch, protein concentrates (fava, whey, rice, pea and soya), and hydrocolloids (κ-carrageenan, arabic gum, xanthan gum, and carboxy methylcellulose). Their rheological, mechanical, and textural properties were systematically analyzed to assess printability. Among all formulations, those containing κ-carrageenan consistently demonstrated superior viscoelastic behavior (G′ > 4000 Pa), optimal tan δ values (0.096–0.169), and yield stress conducive to stable extrusion. These inks also achieved high structural fidelity (93–96% accuracy) and favourable textural attributes such as increased hardness and chewiness. Computational Fluid Dynamics (CFD) simulations further validated the inks’ performances by linking pressure and velocity profiles with rheological parameters. FTIR analysis revealed that gel strengthening was primarily driven by non-covalent interactions, such as hydrogen bonding and electrostatic effects. The integration of empirical measurements and simulation provided a robust framework for evaluating and optimizing printable food gels. These findings contribute to the advancement of personalized and functional 3D-printed foods through data-driven formulation design. Full article

Background and Objectives: Uterine cancer is the most common gynaecologic malignancy in developed countries, yet the psychosocial sequelae of treatment are incompletely described. This prospective, single-centre study quantified six-month changes in the quality of life (QoL) and perceived stress in women with newly diagnosed uterine cancer and explored clinical moderators of change. Methods: Participants completed four validated self-report questionnaires: the 36-item Short-Form Health Survey (SF-36), the 26-item World Health Organization Quality-of-Life-BREF (WHOQOL-BREF), the 30-item EORTC QLQ-C30 and the 10-item Perceived Stress Scale (PSS-10) before therapy and again six months after surgery ± adjuvant chemoradiation. Subgroup analyses were performed for stage (FIGO I–II vs. III–IV). Results: Mean SF-36 Physical Functioning improved from 58.7 ± 12.1 to 63.1 ± 12.6 (Δ = +4.4 ± 7.3; p = 0.000, d = 0.36). PSS declined from 24.1 ± 5.6 to 20.8 ± 5.4 (Δ = −3.3 ± 5.0; p < 0.001, d = 0.66). The WHOQOL-BREF Physical and Psychological domains rose by 4.4 ± 6.9 and 3.5 ± 7.3 points, respectively (both p < 0.01). EORTC QLQ-C30 Global Health increased 5.1 ± 7.6 points (p < 0.001) with parallel reductions in fatigue (−5.4 ± 9.0) and pain (−4.8 ± 8.6). Advanced-stage patients showed larger reductions in stress (ΔPSS −3.5 ± 2.5 vs. −2.3 ± 2.3; p = 0.036) but similar QoL gains. ΔPSS correlated inversely with ΔWHOQOL Psychological (r = −0.53) and ΔSF-36 Mental Health (r = −0.49) and positively with ΔEORTC Global Health (r = −0.42) (all p < 0.001). Conclusions: Over six months, multimodal uterine cancer treatment was associated with clinically meaningful QoL improvements and moderate stress reduction. Greater stress relief paralleled superior gains in psychological and global health indices, highlighting the importance of integrative survivorship care. Full article

To date, various species of Erigeron genus have been used both in the ethnopharmacology of numerous nations across the world and in contemporary herbal practices. The objective of this study is to revise the phytochemical data on the essential oils (EOs) of various fleabanes species and to evaluate the variability of their biological activities. Up to June 2025, this review provides an updated overview of 105 literature sources (published during last 25 years) related to 14 Erigeron sp. (native, naturalized, or invasive) which have been investigated extensively and are of the greatest significance. It summarizes the compositional variability of the EOs and their pharmacological and toxic effects, such as anti-inflammatory, anticancer, antiproliferative, skin regeneration, antioxidant, antifungal, antibacterial, insecticidal, larvicidal, repellent, and allelopathic activity. The EOs of each Erigeron species were characterized, and a chemical structure of 43 major constituents is presented herein. The most characteristic and prevalent compounds were found to be limonene, δ-3-carene, matricaria ester, lachnophyllum ester, germacrene D, β-caryophyllene, β-farnesene, α-bergamotene, allo-aromadendrene, etc., in the EOs from the E. acris, E. annuus, E. bonariensis, E. canadensis, E. floribundus E. mucronatus, and E. speciosus plants. Major constituents, such as borneol, bornyl acetate, modhephen-8-β-ol, cis-arteannuic alcohol, β-caryophyllene, and τ-cadinol, were found in the oils of E. graveolens (Inula graveolens). A paucity of data concerning E. incanus EOs was revealed, with the prevalence of 3-hydroxy-4-methoxy cinammic acid and thymol acetate noted in the oils. The EOs from E. multiradiatus and E. sublyratus were comprised mainly of matricaria and lachnophyllum esters. The available data on EOs of E. ramosus is limited, but the main constituents are known to be α-humulene, 1,8-cineole, eugenol, and globulol. The EOs containing appreciable amounts of matricaria and lachnophyllum esters exhibited strong anticancer, anti-inflammatory, antimicrobial, larvicidal, and repellent activities. Repellence is also related to borneol, bornyl acetate, caryophyllene derivatives, τ-cadinol, modhephen-8-β-ol, and cis-arteannuic alcohol. Cytotoxicity was determined due to the presence of limonene, δ-3-carene, α- and β-farnesene, (E)-β-ocimene, ledene oxide, sesquiphellandrene, and dendrolasin in the fleabanes EOs. Skin regeneration and antifungal properties were related to germacrene D; and anti-inflammatory effects were determined due to high amounts of limonene (E)-β-ocimene, lachnophyllum ester, and germacrene D. The antimicrobial properties of the oils were conditioned by appreciable quantities of limonene, β-pinene, 1,8-cineole, carvacrol, thymol acetae, β-eudesmol, 2,6,7,7α-tetrahydro-1,5-dimethyl-1H-indene-3-carboxaldehyde, caryophyllene and its oxide, allo-aromadendrene, α-humulene, farnesene, carvacrol, and eugenol. This review provides a foundation for further studies on volatile secondary metabolites to explore the potential sources of new biologically active compounds in Erigeron sp. Full article

The $N_k$-index (k-distance degree index) of a connected graph G was first introduced by Naji and Soner as a generalization of the distance degree concept, as $N_k\left(G\right)={\displaystyle \sum _{k=1}^{d\left(G\right)}}\left({\displaystyle \sum _{v\in V\left(G\right)}}{d}_k\left(v\right)\right)k$, where the distance between u and v in G is denoted by $d(u,v)$, the diameter of a graph G is denoted by $d\left(G\right)$, and the degree of a vertex v at distance k is denoted by $d_k\left(v\right)=\{u,v\in V\left(G\right)d(u,v)=k\}$. In this paper, we extend the study of the $N_k$-index of graphs. We introduced some graph transformations and their impact on the $N_k$-index of graph and proved that the star graph has the minimum, and the path graph has the maximum $N_k$-index among the set of all trees on n vertices. We also show that among all trees with fixed maximum-degree $\Delta$, the broom graph $B_{n,\Delta }$ (consisting of a star $S_{\Delta +1}$ and a pendant path of length $n-\Delta -1$ attached to any arbitrary pendant path of star) is a unique tree which maximizes the $N_k$-index. Further, we also defined and proved a graph with maximum $N_k$-index for a given number of n vertices, maximum-degree $\Delta$, and perfect matching among trees. We characterize the starlike trees which minimize the $N_k$-index and propose a unique tree which minimizes the $N_k$-index with diameter d and n vertices among trees. Full article

In view of the problems of slow heat storage process and uneven temperature distribution in the existing phase change heat accumulator, a new type of mesh fin heat accumulator was designed and developed which increased the contact area between the phase change material (PCM) and the fins, enhanced the apparent thermal conductivity of the PCM, improved the heat storage efficiency of the heat accumulator, blocked the PCM, improved the natural convection erosion of the PCM on the upper and lower parts of the heat accumulator, and melted the PCM in each area more evenly. Fluent15.0 was used to numerically simulate the heat storage process of the mesh fins heat accumulator with the finite volume method. The composite PCM prepared by adding 10% mass fraction of expanded graphite to paraffin wax was used as the heat storage material. A 2D, non-steady-state model, incompressible fluid, and the pressure-based solution method were selected. The energy model and the solidification and melting model based on the enthalpy method were used to simulate and calculate the phase change process of PCM. The PISO algorithm was used. The influences of the structural parameters of the mesh fins on the heat storage condition of the heat accumulator were investigated by numerical simulation. The results showed that with the increase in the radius R of the mesh fin, the heat storage time decreased first and then increased. With the increases in vertical fin thickness c, mesh fins thickness δ, and vertical fins number N, the heat storage time decreased. The optimal mesh fin structure parameters were R = 33.5 mm, c = 3 mm, δ = 3 mm, and N = 8, and the heat storage time was 8086 s, which is 47.8% shorter than that of the concentric tube heat accumulator. Otherwise, with the increases in vertical fin thickness c, mesh fins thickness δ, and vertical fins number N, the PCM volume decreased, which shortened PCM melting time. Full article

This paper mainly studies the existence of sign-changing solutions for the following $p\left(x\right)$-biharmonic Kirchhoff-type equations: $-\left(a+b{\int }_{{\mathbb{R}}^N}{\displaystyle \frac{1}{p\left(x\right)}}{|\Delta u|}^{p\left(x\right)}\mathrm{d}x\right){\Delta }_{p\left(x\right)}^{2}u+V\left(x\right){|u|}^{p\left(x\right)-2}u$ = $K\left(x\right)f\left(u\right),x\in {\mathbb{R}}^N$, where ${\Delta }_{p\left(x\right)}^{2}u=\Delta \left({|\Delta u|}^{p\left(x\right)-2}\Delta u\right)$ is the $p\left(x\right)$ biharmonic operator, $a,b>0$ are constants, $N\ge 2$, $V\left(x\right),K\left(x\right)$ are positive continuous functions which vanish at infinity, and the nonlinearity f has subcritical growth. Using the Nehari manifold method, deformation lemma, and other techniques of analysis, it is demonstrated that there are precisely two nodal domains in the problem’s least energy sign-changing solution $u_b$. In addition, the convergence property of $u_b$ as $b\to 0$ is also established. Full article

Linear die filling is currently widely employed in industries. However, there is no comprehensive and systematic model to describe the powder die filling process. This paper utilizes dimensional analysis to extract and analyze various factors that affect the flow characteristics of powder based on DEM-CFD simulations. Several dimensionless parameters including the ratio of particle size to die depth ($d_p{h}_D^{-1}$), solid density number (${\rho }_p{\rho }_g^{-1}$), shoe speed number ($v{\rho }_g{L}_D{\mu }^{-1}$), and force number ($G_p{F}_{Drag}^{-1}$) were proposed based on the Pi theorem. The results showed that the filling ratio δ increased with the increase in $d_p{h}_D^{-1}$ and ${\rho }_p{\rho }_g^{-1}$ due to $G_p{F}_{Drag}^{-1}$ rising. But it decreased with the increase in $v{\rho }_g{L}_D{\mu }^{-1}$ due to the shortening of effective filling time. Finally, a semi-empirical modeling of linear die filling was developed, taking the critical value ${(d_p{h}_D^{-1})}_{90}$ as the dependent variable and the solid density number (${\rho }_p{\rho }_g^{-1}$) and shoe speed number ($v{\rho }_g{L}_D{\mu }^{-1}$) as independent variables. Hence, this model provides a new approach to computing the smallest shoe speed and designing the sizes of dies based on measurable material properties under complete die filling. Full article

The reaction of either the L (2S3R) or D (2R3S) enantiomers of H₂N-C*H(R)CO₂⁻ (R = -C*H(OH)CH₃ or -C*H(OH)CH(CH₃)₂) and the L (2S) or D (2R) enantiomers of H₂N-C*H(C(CH3)₂OH)CO₂⁻ with imidazole-4-carboxaldehyde and nickel(II) acetate in methanol yields a single stereoisomer of an oxazolidine. There is retention of chirality on ring positions 4 and 5 (if C_β is chiral) of the oxazolidine, C_α and C_β of the parent amino acid, and transfer of chirality to the newly generated stereogenic centers, ring positions 3, the amino acid nitrogen atom, N_AA, and 2, the aldehyde carbon atom, C_ald. Specifically, when C_α has an S configuration, both N_AA and C_ald are formed as R. Likewise, a C_α which is R results in both N_AA and C_ald being formed as S. For example, the reaction of L threonine (C_α is S and C_β is R) with 4-imidazolecarboxaldehyde in the presence of nickel(II) gives the facial Λ NiL₂, where L is (2R, 3R, 4S, 5R) 4-carboxylato-5-methyl-2-(4-imidazolyl)-1,3-oxazolidine. The same reaction with D threonine produces the enantiomeric Δ complex of (2S, 3S, 4R, 5S) 4-carboxylato-5-methyl-2-(4-imidazoyl)-1,3-oxazolidine. The high stereospecificity is thought to be based on the fused three-ring structure of the characterized nickel complexes in which the hydrogen atoms of C_α, N_AA, and C_ald must be cis to one another. Identical reactions occur with 2-pyridine carboxaldehyde and LT or DT. In contrast, the reactions of L allo threonine (2S3S) and the primary alcohols, L or D serine, give the conventional meridionally coordinated aldimine product. Full article

Background: Current cosmological fits typically assume a direct relation between cosmic time (t) and the scale factor ($a\left(t\right)$), yet this ansatz remains largely untested across diverse observations. Objectives: We (i) test whether a single power-law scaling ($a\left(t\right)\propto t^{\alpha }$) can reproduce late- and early-time cosmological data and (ii) explore whether a dynamically evolving ($\alpha \left(t\right)$), modeled as a scalar–tensor field, naturally induces directional asymmetry in cosmic evolution. Methods: We fit a constant-$\alpha$ model to four independent datasets: 1701 Pantheon+SH0ES supernovae, 162 gamma-ray bursts, 32 cosmic chronometers, and the Planck 2018 TT spectrum (2507 points). The CMB angular spectrum is mapped onto a logarithmic distance-like scale ($\mu ={log}_{10}{D}_{\ell }$), allowing for unified likelihood analysis. Each dataset yields slightly different preferred values for $H_0$ and $\alpha$; therefore, we also perform a global combined fit. For scalar–tensor dynamics, we integrate $\alpha \left(t\right)$ under three potentials—quadratic, cosine, and parity breaking (${\alpha }^{3}sin\alpha$)—and quantify directionality via forward/backward evolution and Lyapunov exponents. Results: (1) The constant-$\alpha$ model achieves good fits across all datasets. In combined analysis, it yields $H_0\simeq 70\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ and $\alpha \simeq 1.06$, outperforming $\Lambda$CDM globally ($\Delta \mathrm{AIC}\simeq 401254$), though $\Lambda$CDM remains favored for some low-redshift chronometer data. High-redshift GRB and CMB data drive the improved fit. Numerical likelihood evaluations are approximately three times faster than for $\Lambda$CDM. (2) Dynamical $\alpha \left(t\right)$ models exhibit time-directional behavior: under asymmetric potentials, forward evolution displays finite Lyapunov exponents (${\lambda }_L\sim {10}^{-3}$), while backward trajectories remain confined (${\lambda }_L<0$), realizing classical arrow-of-time emergence without entropy or quantum input. Limitations: This study addresses only homogeneous background evolution; perturbations and physical derivations of potentials remain open questions. Conclusions: The time-scaling approach offers a computationally efficient control scenario in cosmological model testing. Scalar–tensor extensions naturally introduce classical time asymmetry that is numerically accessible and observationally testable within current datasets. Code and full data are available. Full article