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Polymer nanocomposite is commonly used to develop structural components of space, aircraft, biomedical, sensor, automobile, and battery sector applications. It remarkably substitutes the heavyweight metallic and nonmetallic engineering materials. The machining principles of polymer nanocomposites are intensely different and complex from traditional metals and alloys. The nonhomogeneity, abrasive, and anisotropic nature differs its machining aspect from conventional metallic materials. This investigation aims to execute the CNC drilling of modified nanocomposite using Graphene–carbon (G-C) @ epoxy matrix. The process constraints, namely, cutting speed (S), feed (F), and wt.% of graphene oxide (GO) vary up to three levels and are designed according to the response surface methodology (RSM) array. The nonlinear model is created to predict surface roughness (Ra) and delamination (Fd) on regression analysis. It has been found that the average error for Ra is 0.94% and for Fd it is 3.27%, which is acceptable in model predictions. The metaheuristics-based evolutionary Dragonfly algorithm (DA) evaluated the optimal parametric condition. The optimal setting prediction for the DA is observed as cutting speed (S)-37.68m/min, feed (F)-80mm/min, and wt.% of graphene oxide (GO)-1%. This algorithm demonstrates a higher application potential than the previous efforts in controlling Ra and Fd values. Both the drilling response values are found to be minimized when the cutting speed increases and the feed decreases. The best fitness value for the DA is 1.626 for surface roughness and 5.086 for delamination. This study agreed with the prediction model’s outcomes and the process parameters’ optimal condition. The defects generated during the sample drilling, such as fiber pull out, uncut/burr, and fiber breakage, were examined using FE-SEM analysis. The optimal findings of the DA module significantly controlled the damages during machining.

This study investigates the mechanical, fatigue, water absorption, and flammability properties of polyethylene terephthalate (PET) core-pineapple fiber sandwich composites reinforced with silane-treated neem fruit husk (NFH) biosilica additives. The novel approach includes modifying the fiber’s surface and incorporating biosilica to enhance environmental resistance. The composites were prepared using a hand layup method, followed by silane treatment of the biosilica, pineapple fiber, PET core and vinyl ester resin. Subsequently, to evaluate environmental impacts on composite’s performance, sandwich composites were subjected to temperature aging at 40^∘C and 60^∘C in a hot oven for 30 days and warm water aging at the same temperatures in tap water with pH 7.4. According to the results, adding 1%, 3%, and 5 vol.% silane-treated biosilica significantly improved the mechanical properties. The composite with 3% biosilica (L2) showed a tensile strength of 120.8MPa, flexural strength of 194.4MPa, compression strength of 182.4MPa, rail shear strength of 20.21MPa, ILSS of 23.14MPa, hardness of 85 Shore-D, and Izod impact strength of 6.56 J. Even under temperature and water aging conditions, the composites showed only minimal reductions in properties, highlighting the efficacy of the silane treatment. The temperature-aged L2 composite had a tensile strength of 104MPa, flexural strength of 172.8 MPa, compression strength of 164MPa, and ILSS of 22.5MPa, while the water-aged L2 composite exhibited a tensile strength of 96MPa, flexural strength of 152.8MPa, compression strength of 146.4MPa, and ILSS of 21.4MPa. Scanning electron microscope (SEM) analysis confirmed uniform dispersion of biosilica particles, critical for improved performance, though higher concentrations led to agglomeration and stress points. The composites also demonstrated excellent flame retardancy, maintaining a UL-94 V-0 rating with decreased flame propagation speeds, specifically 9.05mm/min for L2. These findings underscore the potential of silane-treated biosilica as a reinforcing additive to enhance the durability and performance of composites in adverse conditions.

To study the dynamic response of curved polymer sandwich panels under contact explosion loads, three deformation stages of curved polymer sandwich panels were analyzed. A single degree of freedom rigid plastic dynamic model was established. The bending moment and membrane force effects of the panel and sandwich on deformation were considered in the model. The dynamic response of curved polymer sandwich panels with different panel and sandwich thicknesses under contact explosion loads was calculated through numerical simulation. The mid-span displacement of the panel calculated based on the dynamic model is in good agreement with the numerical calculation results. On this basis, the deformation and velocity changes of the panels were further analyzed, and the force and motion of the panels and sandwich at each stage in the dynamic model were verified. Research has shown that increasing the thickness of panels and sandwich panels can enhance the blast resistance of curved polymer sandwich panels, and increasing the front thickness has a more significant effect on improving the blast resistance of sandwich panels, which can provide a reference for future structural design and engineering applications.

The monomeric and polymeric tetra-aminophthalocyane to, cobalt(II) species adsorbed onto graphite electrodes are active in electrocatalytic oxygen reduction. While the monomeric species is unstable, the polymerized species is an effective and stable reduction catalyst over a wide pH range. Both the two-electron reduction of oxygen to hydrogen peroxide and the four-electron reduction of oxygen to water are characterized by cyclic voltammetry, rotating disc and rotating ring-disc studies with appropriate theoretical analysis. Some mechanistic information is obtained. This is the first cobalt phthalocyanine species to provide a four-electron reduction pathway which exists over a wide pH range and is stable. The stability is associated with the polymerization since the monomeric species is not stable.

The reaction of 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) with cadmium(II) was studied spectrophotometrically and its kinetic and equilibrium constants were determined. The influence of temperature on the reaction rate was also studied. At different ratios of [CPI]/[Cd(II)] two types of complex were formed: CdII(CPI) and (CdII)₂(CPI); an investigation of the solution properties and the mechanism of aggregation of (CdII)₂(CPI) at different pH were performed. It is verified that cadmium(II) accelerates the reaction of the incorporation of manganese(II) into CPI by the substitution of cadmium(II) with manganese(II) in the CdII(CPI) complex; the kinetics and mechanism of this substitution reaction at alkaline pH were studied. A sensitive kinetic method for the determination of cadmium(II) at ppb levels has been established; the molar absorptivity and the Sandell's sensitivity (for A = 0.001) of the recommended procedure at 458 nm and 300 s after the start of the reaction are (6.175 ± 0.026) × 10⁵ 1 mol⁻¹ cm⁻¹ and (1.820 ± 0.008) × 10⁻⁴ μg cm⁻² respectively.

Monomeric and polymeric iron phthalocyanine compounds were synthesized and their dielectric properties were measured in the frequency range from 100 Hz to 10 MHz between 25 and 200 °C. The dielectric constant and dielectric loss showed strong frequency and temperature dependences. Interestingly, large dielectric constants were observed around 100 °C for both monomers and polymers. A dielectric constant as high as 5000 at 110 Hz was observed for the iron phthalocyanine polymer. The origin of the large dielectric constant in metallophthalocyanines is discussed.

Polymer-bound cobalt(II) porphyrins were studied for their dioxygen—binding capacity. Tetra—aminoporphyrins were anchored on a divinylbenzene (DVB)-crosslinked chloromethyl polystyrene network. The crosslinked, solid polymers were swelled in chloroform and the swollen polymers were used for the entire studies. Ortho-, meta- and para-substituted porphyrin systems were developed by adjusting the bonding position with the help of suitably substituted aminoporphyrins. The products were characterized by chemical and spectroscopic methods. Cobalt(II) complexes of polymeric porphyrins were synthesized and characterized by electronic and ESR spectral methods. The spectra gave evidence for the systematic variation of electronic properties in ortho, meta and para compounds and for the dioxygen-binding capacity of cobalt complexes. These results are discussed.

Quantization needs evaluation of all of states of a quantized object rather than its stationary states with respect to its energy. In this paper, we have investigated moduli of a quantized elastica, a quantized loop with an energy functional associated with the Schwarz derivative, on a Riemann sphere ℙ. Then it is proved that its moduli space is decomposed to a set of equivalent classes determined by flows obeying the Korteweg-de Vries (KdV) hierarchy which conserve the energy. Since the flow obeying the KdV hierarchy has a natural topology, it induces topology in the moduli space . Using the topology, is classified.

Studies on a loop space in the category of topological spaces Top are well-established and its cohomological properties are well-known. As the moduli space of a quantized elastica can be regarded as a loop space in the category of differential geometry DGeom, we also proved an existence of a functor between a triangle category related to a loop space in Top and that in DGeom using the induced topology.

As Euler investigated the elliptic integrals and its moduli by observing a shape of classical elastica on , this paper devotes relations between hyperelliptic curves and a quantized elastica on ℙ as an extension of Euler's perspective of elastica.

We consider properties of junctions for the FET geometry were molecular crystals or conducting polymers are used as semiconducting layers. In the molecular crystal Coulomb interaction of free electrons with surface polar phonons of the dielectric layer can lead to selftrapping of carriers and to the formation of a strongly coupled long-range surface polaron. The effect is further enhanced at presence of the bias electric field. The pronounced polaronic effects in conducting polymers change drastically the contact properties of these materials with respect to traditional semiconductors. Instead of the usual band banding near the contact interface, new allowed electronic bands appear inside the band gap. As a result the bias electric field and the injected charge penetrate into the polymer via creation of the soliton lattice which period changes with the distance from the contact surface. The performed studies open the possibility to describe the stationary characteristics and the hysteresis of the FET junctions and the Schottky diodes as well as to explain the photoluminescence suppression or enhancement under the bias electric field.

Using a hybrid simulation method, structural and dynamic response properties of chain macromolecules are studied in a heterogeneous gel matrix in presence of an electrophoretic field E(t) = E_b + E_ssin(2π ft), where E_b is the static field and E_s is the amplitude of sinusoidal field of frequency f. We find that the oscillating field enhances the macromolecular mobility at E_s > E_b while it becomes ineffective at E_s < E_b, consistent with the experimental work of Masubuchi et al. Enhanced segmental and global movement of molecules at E_s > E_b leads to interesting effects such as (i) a significant decrease in molecular clustering, (ii) reduced radius of gyration, and (iii) its linear response to E_b. Power law behavior of molecular motion, i.e., the variation rms displacement (R) with the time steps (t), R ∝ t^ν, is sensitive to temperature, molecular weight, and field.

We investigate the ejection dynamics of a flexible polymer chain out of confined environment by means of scaling considerations and Monte Carlo simulations. Situations of this kind arise in different physical contexts, including a flexible synthetic polymer partially confined in a nanopore and a viral genome partially ejected from its capsid. In the case of cylindric confinement the entropic driving force which pulls the chain out of the pore is argued to be constant once a few persistent lengths are out of the pore. We demonstrate that in this case the ejection dynamics follows a -law with elapsed time t. The mean ejection time τ depends nonmonotonically on chain length N. However, if the geometric constraints comprise a wider capsid chamber attached to a narrow exit tube, the mechanism of ejection changes and involves the surmounting of an activation barrier. The driving force then varies in time. One finds good agreement of theory and computer simulation with recent experiments with DNA.

The mathematical formalisms and computer enumerations of two polymeric models: trails and silhouettes are presented. Trails have been quite extensively studied, but their equivalence class, silhouettes are less familiar. By drawing parallelism from n→0 magnetic analog, the tricritical properties of silhouettes are studied both analytically and numerically. The tricriticality of trails, which is inaccessible by a renormalization group analysis in ε=4−D dimensions, can therefore only be investigated numerically. The tricritical exponents thus obtained indicate that trails belong to a distinct universality class from silhouettes.

We have prepared three C₆₀ polymers under high-temperature and high-pressure conditions, and confirmed them to be orthorhombic (1D), tetragonal and rhombohedral (2D) polymer by XRD method, respectively. The ¹³C MAS NMR spectra of both orthorhombic and rhombohedral polymer have been measured and two resonance peaks observed. One resonance at 73 ppm resulted from the sp³ carbons with an intermolecular bonding, the other at 145 ppm is from the inequivalent sp² carbons on the C₆₀ molecule. For 1D polymer, the fine structure of the main peak at 145 ppm has been analyzed. By simulation of the ¹³C MAS NMR peak shape of the inequivalent carbons, we propose that there exist nine inequivalent carbons on a C₆₀ molecule in the orthorhombic (1D) polymer.

Dynamic Monte Carlo simulations are performed for lattice self-avoiding tail-like polymer chains with one end attached to a non-interacting and impenetrable flat surface. The configurational entropy S_TL of the tail-like chain is determined by the scanning method. The entropy S_TL is smaller than that of the free chain without surface S_F. The entropy drop ΔS=S_F-S_TL increases linearly with lnn for short chains and increases linearly with n for long chains. However, the average entropy drop per bead ΔS/n decreases with n, indicating that the average effect of the surface on one chain bead decreases with the increase in chain length.

The purpose of this study is to obtain some information about the viscoelastic properties of the material and to see the effect of the addition of plasticizer on these properties. In particular, we try to study the loss of plasticizer, caused by ageing under conditions of utilization, on the properties of material at the neighborhood of vitreous transition.

Using a viscoelastimeter, the study of a polyamide-11 (PA11) at the neighborhood of its temperature of vitreous transition Tv has shown that the increase of the plasticizer rate clearly improves the properties of the material by decreasing its Tv temperature. The comparison of the curves giving the modulus of elasticity E' of the various samples showed that the mechanical properties of the material improve with the increase of the concentration of plasticizer, but ageing reduces this improvement by causing the loss of plasticizer, thus, the temperature range of utilization of material is reduced.

The translocation of polymer chain through an interacting pore under chemical potential difference Δμ is simulated using Monte Carlo technique. Three translocation modes, dependent on the polymer–pore interaction ε and Δμ, are discovered. The translocation process is found to be an nonequilibrium process, which influences the dependence of translocation time τ on ε and Δμ. It is found that τ decreases in a power law relation with the increase of Δμ, and the exponent is dependent on the interaction.

Diffusion of polymer in narrow periodical channels, patterned alternately into part $\alpha$ and part $\beta$ with the same length $l_p/2$, was studied by using Monte Carlo simulation. The interaction between polymer and channel $\alpha$ is purely repulsive, while that between polymer and channel $\beta$ is attractive. Results show that the diffusion of polymer is remarkably affected by the periodicity of channel, and the diffusion constant $D$ changes periodically with the polymer length $N$. At the peaks of $D$, the projected length of polymer along the channel is an even multiple of $l_p/2$, and the diffusion of polymer in periodical channel is nearly the same as that of polymer in homogeneous channel. While at the valleys of $D$, the projected length of polymer is an odd multiple of $l_p/2$, and polymer is in a trapped state for a long time and it rapidly jumps to other trapped regions during the diffusion process. The physical mechanisms are discussed from the view of polymer–channel interaction energy landscape.

Materials having nanoscale structures have shown potentials for applications in microelectronics, biomedicine and energy storage. A continuing challenge is the capability of fabricating multi-function nanodevices with controlled nanostructures and excellent performances. Measurement platforms, which provide accurate and detailed information on internal structures, surface morphologies, mechanical properties and electrochemical properties are a key to this challenge. In this review, we, in particular, highlight the crucial role of measurement techniques in quantifying these nanostructures and their properties.

The measurement of patients’ dosages of radiation caused by medical diagnostics continues to be challenging. A Cantor sequence photonic crystal structure using porous silicon doped with a polymer of polyvinyl alcohol, carbol fuchsin and crystal violet (DPV) is proposed. The influence rules of geometrical and optical parameters such as the radiation doses, number of periods, porosity of porous layers, incident angle and thickness of layers are investigated using MATLAB based on the transfer matrix method. The transmittance of the Cantor sequence of a defective photonic crystal sensor under different conditions is investigated to select the optimum conditions. The proposed system recorded the accepted sensitivity of 0.265nm/Gy, FoM of 6.5Gy${}^{-1}$, Q of 12,701, RS of $6\times 10^{-3}$ and LoD of $8\times 10^{-3}$ for gamma radiation. The suggested detector has simple design, accurate monitoring efficiency and immense potential for gamma radiation sensing.

In this work, the structure, dielectric and optical properties of PVDF/zirconia-based polymer nanocomposites were investigated. The morphology and structure of the nanocomposites were analyzed by XRD, SEM, FT-IR, UV and EDS analyses. It was determined that the forbidden gap for the PVDF/1%ZrO₂-based nanocomposite is 4.7eV, for PVDF/5%ZrO₂-4.5eV, and for PVDF/10%ZrO₂-4.2eV. It is shown that the dielectric permittivity of the nanocomposites increases sharply up to 3% of ZrO₂ nanoparticles in the polymer and then decreases slightly with an increase in the concentration of nanoparticles. An increase in the permittivity indicates an increase in polarization processes in nanocomposites at a 3% conentration of ZrO₂ nanoparticles in the PVDF matrix. It has been established that the dielectric loss tangent at low frequencies starts to decrease, and at high frequencies, it increases. The increase in the dielectric loss tangent at high frequencies is explained by an increase in relaxation processes and energy dissipation in these systems.