Physical Sciences

Abstract: Sodium-ion batteries are generally considered a promising alternative to lithium-ion batteries due to the abundance and low cost of sodium. However, their main limitation is the lack of an appropriate anode, since the usual graphite electrode used in lithium batteries is incompatible with the larger ionic radius of sodium. In this work, the theoretical behavior of pillared graphene as a possible anode is analyzed via computational simulations based on Density Functional Theory (DFT), using the FIREBALL program. The structural relaxation results reveal that staggered pillars are more stable than the aligned alternative. The adsorption energy of sodium is shown to be significantly higher than for graphite, with a maximum value of −2.23 eV, leading to an important energetic benefit. The diffusion analysis shows an exceptional mobility of sodium, with migration barriers comparable to lithium ions both in the flat regions of the structure and close to the nanotubes. The values are appreciably lower than in the standard graphite used in current batteries. Finally, the charge analysis confirms a significant electronic transfer from both sodium and lithium to the lattice. These data indicate that pillared graphene can be a good candidate for the optimization of charge dynamics in sodium-ion batteries.

Abstract: During the study of premixed NH₃/CH₄ fuel mixtures, flame separation into two reaction zones was observed upon flashback into a Bunsen burner. Stable combustion regimes were obtained, with a gap between the burner rim and the upper luminous region, the size of which depended on the mixture composition and the position of the combustion zone inside the burner. The influence of the equivalence ratio and the ammonia mole fraction on the separation effect was examined. At the burner exit, temperature and gas composition profiles were measured. Flame emission was recorded at the chemiluminescence bands of OH* (308 nm) and CH* (431 nm), and emission spectra were acquired both inside and outside the burner. Spectral analysis revealed a band corresponding to NO₂ emission in the upper part of the luminous region. It is most likely that nitrogen dioxide is formed through low temperature reactions occurring when the combustion products mix with atmospheric air.

Abstract: The report presents the results of broadband dielectric spectroscopy (BDS) studies in bulk nanocolloids: E7 liquid crystalline (LC) mixture plus C₆₀ fullerene nanoparticles. BDS spectra for 260 temperatures from the isotropic liquid (I) phase at ~360K to the nematic (N) phase at the glass temperature T_g~220K was tested. The analysis focused on pretransitional critical-like features and complex glassy dynamics, highlighting their interplay and dominance. This is associated with pretransitional fluctuations, which impact the nematic phase even 90 K below the I-N transition. On approaching T_g, strong previtreous changes detected via dielectric constant and the loss curve maximum appear, starting at T_g+30K. The critical-like behavior on T→T_g appears explicitly also for the parameter describing the distribution of relaxation times. For the 3 main relaxation times in the long-range nematic phase, the optimal portrayal via the new Critical & Activated equation is evidenced. The derivative-based test of coupling/decoupling between translational and orientational processes reveals strong decoupling with the fractional exponent F< 1 below the I-N transition and related to F< 1 above T_g. Notable is the permanent ‘parallel’ orientation of LC molecules by C₆₀ fullerene nanoparticles, which can be significant for applications.

Abstract: This study examines the possibility of plastic deformation in low-modulus gels and yielding liquids. The model systems were a gelatin-sodium alginate hydrogel and the same gel filled with nanoscale zinc oxide particles. The experiments involved short- and long-term observations of deformation development under a prescribed shear stress, followed by stress removal and monitoring of deformation recovery. The initial hydrogel is a typical soft-matter system with an elastic modulus of 63 Pa. At low stresses, residual deformations were observed in addition to elastic deformations; these residual deformations reached up to ap-proximately one half of the total deformation. They appeared instantaneously, depended on the applied stress, and did not change during long-term observation. This behavior is characteristic of plastic deformation. The incorporation of 5% dispersed ZnO nanoparticles converted the gel into a yielding liquid. This transition is at-tributed to partial disruption of the physical network, as evidenced by a sharp decrease in the elastic modulus to 18 Pa and by comparison of the FTIR spectra of the unfilled gel and the nanoparticle-modified gel. The yield stress of the yielding liquid was 7 Pa. However, at stresses below this value, while the material remained in a gel-like state, steady-state flow with a very high viscosity, on the order of 10⁵-10⁶ Pa s, was detected. After the yield point was exceeded, steady-state flow with a much lower viscosity, on the order of 3 Pa s, occurred, as is characteristic of conventional liquids containing a solid filler. Nevertheless, a small fraction of plastic defor-mation was still observed. Thus, the experimental results show that physical gels can behave as elastic-plastic media and that yielding liquids may flow below the yield point with very high viscosity. The phenomenon of plasticity should therefore be taken into account when developing rheological models of yielding liquids

Abstract: Laser-ignited particle combustion is critical to energy, aerospace, and defense applications, yet understanding its physicochemical mechanisms is hindered by poor reproducibility in combustion data from randomly packed samples. While classical theory attributes data inconsistency to variations in packing density, we propose instead that consistency of the surface layer morphology—given the nanoscale laser penetration depth—is the dominant factor. A two-dimensional Discrete Element Model showed that increasing particle layers markedly reduces surface topography conformity, while gravitational settling maintains packing density near its theoretical maximum. An innovative constrained droplet method was developed for sample preparation, integrating multi-stage sieving, equal-circle packing in a circle theory, alongside droplet deposition to build multilayer samples mirroring computational models. In-situ laser ignition diagnostics revealed that key combustion metrics—spectral profiles, temporal evolution, ignition delay, and combustion duration—exhibit a rapid decline in consistency with increasing layers, closely matching the simulated decay in surface morphology conformity. Contrary to long-held assumptions, this work robustly shows that surface morphology governs laser-ignition experimental reproducibility. This paradigm-shifting finding redefines the controlling mechanism in laser-ignited combustion of random particle packings, thereby provides a method for refining sample preparation and enables the accurate determination of key parameters that remain elusive with conventional approaches.

Abstract: Ecosystem disruption is a significant challenge of the contemporary age, arising from substantial CO₂/CO emissions resulting from dependence on fossil fuels as a primary energy source. Scholars across several fields are striving to mitigate these severe greenhouse gas emissions. The most promising method is absorbing carbon and transforming it into sustainable energy. We sought to diminish CO levels by electrocatalytic reduction using innovative catalytic surfaces, namely transition metal phosphides (TMPs). During this work, VP is recognized as a very effective surface for CO reduction and the synthesis of methane, methanol, and formaldehyde at -0.68 V. Further, hydrogen evolution does not pose a challenge for any surface, despite all TMPs facilitating CO reduction. Overall, predictions from these DFT-guided predictions, experimentalists can get insight for their experimental validation and synthesize of active catalysts for CO conversion and green energy production.

Abstract: This paper presents a concept of a new class of multifunctional adaptive elements for neuromorphic electronics, based on the mathematical framework of the Kuznetsov tensor. The proposed element integrates the functions of information storage, processing, and redistribution, providing high adaptability to changing system conditions while preventing overloads, singular states, and data losses. The Kuznetsov tensor enables modeling of multidimensional metrics of local and global flows of energy and information within neuromorphic networks, ensuring optimization of computational processes at both individual node and network-wide levels.The element demonstrates the potential of a self-regulating redistribution architecture, capable of dynamically adapting to workload variations and changes in connection topology, maintaining system stability and enhancing energy efficiency. This concept can be applied in neuromorphic processors, quantum computing devices, and artificial intelligence systems requiring predictable and reliable operation of complex multidimensional networks.The paper discusses the fundamental operating principles of the element, the mechanisms of interaction with information and energy flows, and integration possibilities within modern computational architectures. The proposed approach opens new avenues for the development of intelligent adaptive devices, capable of managing information and energy dynamics considering singularities and entropy-driven processes, which is of interest for both fundamental and applied research in neuromorphic electronics and information technology.

Abstract: Here we perform a detailed information-theoretic (IT) analysis of atomic electron densities in the Periodic Table, from hydrogen (Z = 1) to lawrencium (Z = 103). By use of the Shannon entropy, the Fisher information and the disequilibrium functional in both position and momentum spaces as fundamental descriptors of the atomic densities, the Periodic Table can be represented in our three-dimensional information space as a continuous, highly ordered manifold. The analysis shows that chemical periodicity naturally reveals a geometrical spiral at the coordinates of theoretic-information space (Shannon, Fisher, Disequilibrium), with each period forming one segment within the continuous global trajectory. We find information-theoretic signatures of shell structure, subshell filling, and electron-configuration anomalies, such as the familiar irregularities seen in chromium and copper. Through the uncertainty principle of complementary analysis in momentum space, more insights are gained by exposing maximal information-theoretic differentiation for lighter atoms and compression among heavy elements. We demonstrate, by considering triadic relationships and complexity properties in relation to the López-Mancini-Ruiz (LMC) and Fisher-Shannon (FS) functionals, that atomic complexity increases monotonically along with nuclear charge and we provide a quantitative measure of how organized atomic electron densities are distributed throughout the periodic system. Based on our IT analyses, the fundamental character of periodicity could be addressed by employing spiral representations that continue the characteristic of hydrogen, but also preserving the autonomy of the blocks of elements.

Abstract: Hydrophobicity and hydrophilicity are incompatible. On a hydrophobic substrate, a macroscopic droplet always exhibits a morphology with contact angle higher than 90∘, never lower than 90∘. In this paper, we theoretically demonstrate the possibility that a nanoscale droplet can exhibit a contact angle lower than 90∘ on the same hydrophobic substrate. To demonstrate this, we analyze the morphology and contact angle of a sessile droplet on smooth flat substrates, taking into account disjoining pressure. By constraining the two-dimensional cylindrical droplet and minimizing the free-energy functional, we derive a formula to determine the droplet’s morphology and the boundary between hydrophilic and hydrophobic contact angle for finite-sized droplets. Using this formulation, we reconsider the formula for the macroscopic contact angle, known as the Derjaguin-Frumkin formula. By utilizing a simple disjoing pressure model, we find that the calculated contact angle at the nanoscale is always smaller than the macroscopic contact angle determined by the Derjaguin-Frumkin formula. Consequently, the wettability (hydropilicity/hydrophobicity) differs at the nanoscale compared to the macroscale. We further discuss the implication of our results on the size-dependent contact angle and line tension at the nanoscale.

Abstract: Lipid vesicles and related nanocarriers often contain two compartments, such as the inner and outer leaflets of a bilayer membrane between which amphipathic molecules can migrate. We develop a stochastic model for describing the transfer kinetics of cargo between the two compartments in an ensemble of carriers, neglecting inter-carrier exchange to focus exclusively on intra-carrier redistribution. Starting from a set of rate equations, we examine the Gaussian regime in the limit of low cargo occupation where Gaussian and Poissonian statistics overlap. We derive a Fokker–Planck equation that we solve analytically for any initial cargo distribution among the carriers. Moments of the predicted distributions and examples, including a comparison between numerical solutions of the rate equations and the analytic solutions of the Fokker–Planck equation, are presented and discussed, thereby establishing a theoretical foundation to study coupled intra- and inter-carrier transport processes in mobile nanocarrier systems.

Abstract: In this study, we investigated the impact of incorporating energetic substituents such as –NO₂, –NH₂, –Cl, –F, N-methyl-N-nitro (CH₃–N–NO₂), and picryl on the detonation performance and stability of acridone-based compounds. The DFT B3LYP/cc-pVTZ method was employed to evaluate key molecular properties, including the HOMO–LUMO gap, cohesive energy, chemical hardness, and electronegativity. Based on these parameters, changes in chemical and thermal stability were assessed. The results highlight the significant influence of both the type and position of substituents on the energetic performance and stability of the compounds studied. Notably, the acridone derivative bearing a picryl group and four –NH₂ substituents exhibited energetic properties superior to those of TNT. However, the analysis of stability and sensitivity—based on oxygen balance—suggests that such substitutions generally reduce stability. This reduction, however, is dependent on both the nature and number of substituents introduced.

Abstract: We resolve palladium’s long-standing Madelung “anomaly” by proving that its ground–state con- figuration, [Kr] 4d¹⁰5s⁰, is the generic outcome of a spectral phase transition in a self–adjoint radial Hamiltonian on Hrad = L²(R+, r²dr). The decisive operator invariant is the asymptotic level V_∞ = μ + Γ0 (r → ∞) of bL = −∇² + Γ(r) + μ. For V_∞ > 0, Hardy control, Birman–Schwinger bounds, and the Rayleigh–Ritz variational form enforce spectral locking in the s channel: the projector Ps selects the trivial amplitude, P_sΨ ≡ 0. Agmon estimates yield an evanescent length λ_s = (V∞ − E)^−1/2; a representative Pd fit gives λs ≈ 0.18 ˚A and > 99.9% suppression of 5s density within r < 0.5 ˚A. The extinction/survival dichotomy is a Z₂ spectral–topological invariant determined solely by sign V∞, with a sharp phase boundary at V∞ = 0. Levinson’s theorem organizes Group 10 systematics as spectral flow across that boundary: Ni sits near the index jump (marginal), Pd lies deep in the extinct phase (Ps = 0), and Pt shows partial reactivation by relativistic softening. A compact, falsifiable classifier, κ(Z) = Z ∞ 0 r μ(Z) + Γ(r; Z)
− dr, provides a parameter–free integral indicator of extinction. Chemically, s–extinction narrows the d manifold, shifts the d–band center toward εF , removes isotropic mixing channels, and explains square–planar preference, d–dominated screening in XPS/ EELS, and vanishing Fermi–contact/Knight terms. The angle–integrated XPS intensity, written in operator form I(ω) ∝ TrD†δ(ω−( bH−EF ))D ρ0 , exhibits null s–resolved weight near threshold in Pd, matching P_sΨ ≡ 0 and anchoring the theory operando. A coarse–grained Landau functional for χs = ∥PsΨ∥² captures amplitude selection and the bifurcation at V_∞ = 0. Finally, V_∞ maps tangible design knobs—alloying, strain, coverage, and support/ligand fields—onto phase control, enabling testable targets (λ_s, a_s, ε_d) for diagnosing and engineering orbital extinction/reactivation across the periodic table.

Abstract: Periodic anomalies in the electronic configurations of transition and related metals have long re- sisted straightforward explanation. Here it is shown that these so-called exceptions are not accidental but arise as quantized, topologically protected features of the atomic spectrum. By formulating the Hamiltonian in terms of spectral branches over parameter space, each anomalous configuration is identified with a singularity—indexed by invariants such as Berry phase, Chern number, or winding number—between distinct symmetry-adapted states. This spectral–topological approach unifies ob- served and predicted anomalies within a single mathematical structure, recasting the periodic table as a landscape of topological transitions rather than empirical rules. The results provide a predictive ex- planation for electronic anomalies and suggest new avenues for the design of materials and quantum systems with tailored properties.

Abstract: Classical Molecular Dynamics simulations were used to investigate the interfacial adsorption of ethane on ultrathin molten polyethylene films. We investigated the interfacial adsorption of supercritical ethane on ultrathin molten polyethylene films at various temperatures (298.15 - 448.15 K) and pressures (0.28 - 13.17 MPa). Ethane was found to accumulate preferentially at the film's interfaces rather than dissolving into the film's core. The ultra-thin, metastable films, studied at their mechanical stability limit, are composed of two overlapping interfaces. The films show some fractions of interfacial chains transiently desorbing from the film surface and entering the gas phase, which facilitates the accumulation of ethane at the interfaces. At 373.15 K and pressures between 0.29 and 9.65 MPa, the combined film interfaces adsorb between 4.8 and 8.6 times more ethane than the amount solubilized in the central, bulk region of the film. Interfacial tension decreases exponentially with increasing gas pressure. Interfacial tension is primarily governed by inter-chain interactions at the interface. Minor contributions arise from the vibrational dynamics of polyethylene chain fractions that transiently desorb from the film surface. Furthermore, the solubility of ethane in the film's bulk region exhibits a temperature-dependent inversion: at 298.15 K, the ethane density in the film's center slightly exceeds that of the bulk gas, but this trend reverses at 373.15 K and becomes more pronounced as the temperature increases. This indicates a potential solubility transition temperature between 298.15 and 373.15 K.

Abstract: Avogadro’s number is one of the profound constants of science—quantifying the relationship between the atomic and macroscopic worlds. This review traces its evolution from theoretical origins and experimental measurement to its exact status as a defining SI constant. Special emphasis is placed on our innovative work based on computational framework for estimating the unified atomic mass unit (UAMU) and Avogadro number. Our approach, grounded in first-principles of nuclear physics and realized in transparent Python algorithms, uniquely relates macroscopic constants directly to nuclear binding energies across a broad range of elements and nuclides. By demonstrating that Avogadro’s number is essentially the inverse of the computed UAMU, and by systematically analysing results from both advanced semi-empirical mass models and our Strong and Electroweak Mass Formula, our approach reveals a deep physical interplay between nuclear saturation and the emergence of Avogadro’s constant. This computational paradigm, adaptable to AI-driven improvements and new nuclear data, offers powerful pedagogical, conceptual, and research benefits, complementing established experimental methods. The review discusses these advances alongside the historical, scientific, and educational significance of Avogadro’s number, and concludes by outlining future prospects at the intersection of nuclear physics, computation, and fundamental metrology. Following a crude approximation, for Z = (1 to 140) having 15504 atomic nuclides, estimated value of the Avogadro number is, (6.017052 to 6.017185) x10^26 atoms/kg. It needs a review with respect to conceptual validation, statistical procedures and python program changes/corrections/updates.

Abstract: We analyze the high-order above-threshold ionization (HATI) process of small polyatomic molecule with C3 symmetry, which is induced by a bicircular strong laser field. This field consists of two coplanar, counter-rotating, circularly polarized components with frequencies rω and sω where r and s are integers. In our study, we use an improved molecular strong-field approximation to obtain electron energy- and angle-resolved spectra of BF3 molecule. We analyze the contributions of individual atoms as well as the impact of molecular symmetries on these spectra. We find that these spectra are significantly affected by the characteristics of the molecule and the laser-field parameters. Furthermore, we observe pronounced interference minima in the HATI spectra. We demonstrate that these minima result from the destructive interference of rescattered wave packets from different atomic centers, and we determine the conditions under which they occur, including two-, three-, and four-center interference.

Abstract: The incorporation of MAX phase interface layers into silicon carbide (SiC) composites has been shown to significantly enhance mechanical properties, particularly under irradiation conditions. However, conventional Ti-based MAX phases suffer from thermal instability and tend to decompose at high temperatures. In this work, Sc₂SnC coating was successfully synthesized on the surface of SiC fibers (SiC_f) via an in-situ reaction between metals and pyrolytic carbon (PyC) in a molten salt environment. The PyC layer, pre-deposited by chemical vapor deposition (CVD), served as both a carbon source and a structural template. Characterization by SEM, XRD, and Raman spectroscopy confirmed the formation of Sc₂SnC coatings with a distinctive hexagonal flake-like morphology, accompanied by an internal ScC_x intermediate layer. By turning the Sc-to-Sn ratio in the molten salt, coatings with varied morphologies were achieved. ScC_x was identified as a critical intermediate phase in the synthesis process. The formation of numerous defects during the reaction enhanced element diffusion, resulting in preferential growth orientations and diverse grain structures in the Sc₂SnC coating.

Abstract: The electrochemical performances of Li-ion batteries based on LiFePO4(LFP) cathode supported by bio sourced activated carbon obtained from Millet Cob (MC) or Water Hyacinth (WH) were determined. The carbons were obtained by combustion prior to drying the raw materials of WH and MC, followed by steps of various chemical cleanings, were activated at the following different mass ratios of potassium hydroxide (KOH) and WH or MC respectively: KOH/WH 1:1, 2:1, and 5:1, and KOH/MC 1:1, 2:1, and 5:1.The physics properties (X-ray diffraction patterns, BET surface area, micropore and mesopore volume, conductivity, etc. ) and electrochemical performances (specific capacity, discharge at various current rates, electrochemical impedance measurement, etc.) were determined. The electrochemical performances of coin cells based on cathodes composed of 85% LiFePO4, 8% of these activated carbons, and 7% polyvinylidene fluoride (PVDF) as a binder, with lithium metal as the anode were studied. Cycling tests and the discharge at different current rates of these cells based on the LiFePO4/C cathodes supported by the various activated carbons were achieved. It was found that the coulombic efficiency, the specific capacity and the discharge at different current densities of these cells were interesting for Li-ion batteries applications. It was shown that their Coulombic efficiency was at least 99% and was very close to that of the cell based on LFP/commercial graphite cathode. The specific capacity of the cells was correlated to the KOH/WH et KOH/MC. Overall, the electrochemical performances of cells based on LFP/MC and LFP/WH were correlated to the physics properties of the activated carbons of MC and WH. Their performances were also compared to those of cells based on LFP/graphite. It was found that cells based on activated carbon obtained from WH exhibited better performances than those from MC. For a given current rate and the same number of cycles, the specific capacity of the cells based on activated carbons of WH is very close to that based on graphite.

Abstract: Toroidal and Klein-bottle fullerenes share a peculiar topological symmetry whose existence has been recently proposed. This symmetry is valid for certain sizes of the lattices. Here some new topological features are presented for a better understanding of the phenomenon between the two polyhexes outside the symmetrical region. Lastly, we introduce here the enhanced-by-topology expansion, an original topological novel effect that arises from the Toroidal / Klein-bottle symmetry.

Abstract: The mean force between two highly like-charged macroions in the presence of monovalent counterions and added multivalent salt, within solvents of varying dielectric constants has been studied using Monte Carlo simulations. Without additional salt, the mean force is strongly repulsive at all macroion separations in solvents with a dielectric constant ϵ_r ≥ 30. However, in solvents having ϵ_r ≤ 30, the macroions experience effective attraction, indicating that attractive interactions between highly charged macroions can occur even without multivalent salt in nonpolar solvents with low dielectric constants. At a multivalent counterion-to-macroion charge ratio of β = 0.075, the mean force becomes attractive at short separations in solvents with ϵ_r = 54 containing 1:3 salt, as well as in all solvents with 1:5 salt, while still exhibiting significant repulsion at longer separations. In contrast, for solvents with 1:3 salt and dielectric constants ϵ_r = 68 and ϵ_r = 78.4, the mean force turns attractive at a higher salt concentration, around β = 0.225. The shift of the mean force to an attractive state at short separations signifies charge inversion on the macroion surface when a sufficient amount of salt is present. At a stoichiometric ratio of multivalent counterions, long-range repulsion vanishes, and attraction becomes significant. However, with excess salt, the strength of the attractive mean force diminishes. Additionally, the attractive force at a given salt concentration increases as the dielectric constant decreases and is stronger in systems with 1:5 salt than in those with 1:3 salt.