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The investigation of integral elastic cross-section (ICS), momentum transfer cross-section (MTCS), viscosity cross-section (VCS), absorption cross-section (ABSCS), and total cross-section (TCS) of atoms by electron (e−) and positron (e+) impact is very crucial and essential for understanding fundamental atomic processes and their applications in various fields such as plasma physics, molecular physics, and astrophysics. This study investigates and analyses the ICS, MTCS, VCS, ABSCS, and TCS of the atoms, Li, Be, B, Ti, and W, over a wide energy range. By employing the computational Optical Potential Method (OPM) and quantum scattering integrated in a computational package, ELSEPA (Elastic scattering of electrons and positrons by atoms, positive ions and molecules), the cross-sections of atoms by electron and positron impact are calculated. The present results shows good agreement with all the experimental and theoretical data available in the literature. The obtained cross-sections may facilitate the development of accurate models for plasma simulations and fusion research.

Investigation on intrinsic properties of photosynthetic pigment molecules participating in solar energy absorption and excitation, especially their eigen-absorption cross-section ( σ ik ) and effective absorption cross-section ( σ ′ ik ), is important to understand photosynthesis. Here, we present the development and application of a new method to determine these parameters, based on a mechanistic model of the photosynthetic electron flow-light response. The analysis with our method of a series of previously collected chlorophyll a fluorescence data shows that the absorption cross-section of photosynthetic pigment molecules has different values of approximately 10 −21 m 2 , for several photosynthetic organisms grown under various conditions: (1) the conifer Abies alba Mill., grown under high light or low light; (2) Taxus baccata L., grown under fertilization or non-fertilization conditions; (3) Glycine max L. (Merr.), grown under a CO 2 concentration of 400 or 600 μmol CO 2 mol −1 in a leaf chamber under shaded conditions; (4) Zea mays L., at temperatures of 30°C or 35°C in a leaf chamber; (5) Osmanthus fragrans Loureiro, with shaded-leaf or sun-leaf; and (6) the cyanobacterium Microcystis aeruginosa FACHB905, grown under two different nitrogen supplies. Our results show that σ ik has the same order of magnitude (approximately 10 −21 m 2 ), and σ ′ ik for these species decreases with increasing light intensity, demonstrating the operation of a key regulatory mechanism to reduce solar absorption and avoid high light damage. Moreover, compared with other approaches, both σ ik and σ ′ ik can be more easily estimated by our method, even under various growth conditions (e.g., different light environment; different CO 2 , NO 2 , O 2 , and O 3 concentrations; air temperatures; or water stress), regardless of the type of the sample (e.g., dilute or concentrated cell suspensions or leaves). Our results also show that CO 2 concentration and temperature have little effect on σ ik values for G. max and Z. mays . Consequently, our approach provides a powerful tool to investigate light energy absorption of photosynthetic pigment molecules and gives us new information on how plants and cyanobacteria modify their light-harvesting properties under different stress conditions.

In this paper, to improve the vibrational response of microstructures, the impact of the nonlinear modal analysis of axially functionally graded (AFG) truncated conical micro-scale tube including the thermal loading for the different type of cross sections such as uniform section, linear tapered section, convex section, the exponential section are studied that are applicable for various application, for example, the micro-thermal fins, macro-/micro-fluid-flow diffuser, fluid-flow nozzle, fluid-flow throat, micro-sensor, etc. The nonlinear equations are obtained applying Hamilton’s principles based on the modified couple stress to determine the size effect and Euler–Bernoulli beam theory considering the von-Kármán’s nonlinear strain. The material combination varies along the tube’s length, denouncing the AFG tube made by metal and ceramic phases. The nonlinear equations are solved by applying a couple of homotopy perturbation methods (HPM) to calculating the nonlinear results and the generalized differential quadrature method (GDQM) to providing the initial conditions. The linear and nonlinear results presented the effect of various cross sections and other parameters on the micro-tube frequency that are valuable to design and manufacture the micro-electro-mechanical systems (MEMS).

Measured the effective atomic number(Zeff), effective electron density (Neff), atomic cross-section (бt)and electronic cross-section (бe)depending on the amount of mass attenuation coefficient, the mass attenuation coefficients (μm)measured for fatty acid \"Caprylic\" C8H16O2by using Gamma ray radiation(γ), emitted from sources Co57, Ba133, Na22, Cs137, Mn54, and Co60with energies from 122 to1330 keV. We used scintillation NaI(Tl) detector with resolution 8.2% (at 662keV ). The attenuation coefficient data were then used to obtain the effective atomic numbers (Zeff), and effective electron densities (Neff), atomic cross-section (бt)and electronic cross-section (бe) off atty acids. It was observed that the effective atomic number (Zeff) and effective electron densities (Neff) initially decrease and tend to be almost constant as a function of gamma-ray energy. Zeff and Neff experimental values showed good agreement with the theoretical. Data on interaction of photons of energy (below 1500 keV) with biological compounds are used in radiation therapy, especially for dose calculations.

In this paper, the bending and buckling analysis of microbeam with the uniform and non-uniform cylindrical cross-section was examined based on the classical beam theory and the modified couple stress theory to model the micro-structures effects. The nonlinear effect of the Von-Kármán theory is regarded to study the large-deflection effect on the buckling of microtubes. The conservation energy principle is used to derive the nonlinear equation of motion and the boundary conditions. The effect of several applicable cross-sections, including the linear, exponential, and convex function, on the static behavior of cylindrical beam is investigated, which is made by the porosity-dependent axially functionally graded material. The homotopy perturbation technique as a semi-analytical solution, coupled with the generalized differential quadrature method, is employed to obtain the nonlinear results. Eventually, the influence of various parameters such as the porosity, volume fraction index, bending load, nonlinear deflection, length-scale effect on the bending deflection, and buckling of microbeam with both clamped and pinned supported are analyzed in details.

The exotic deformed nucleus [sup.31]Ne is studied with an approach that combines self-consistent structure and reaction theories. The deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) is utilized to demonstrate that deformation and pairing correlations give rise to a halo structure with a large-amplitude p-wave configuration in [sup.31]Ne. Then the valence nucleon wave functions and angle-averaged density distributions of [sup.30]Ne from this theory are used as input for the Glauber reaction model to study the observables of neutron-rich neon isotopes to search halo signatures. With NL1 effective interaction, our predictions of the reaction cross sections for these exotic neon isotopes on a carbon target can better reproduce the experimental data than those from the relativistic mean field model for a spherical shape with resonances and pairing correlation contributions, and are roughly 3.3% (~ 50 mb) larger than those with Gaussian function-fitted densities of the core nuclei. The calculated one-neutron removal cross section at 240 MeV/nucleon, and the inclusive longitudinal momentum distribution of the [sup.30]Ne residues from the [sup.31]Ne breakup reaction are largely improved over previous theoretical predictions and agree well with data. These reaction evaluations indicate a dilute density distribution in coordinate space and are a canonical signature of a halo structure. Moreover, our predictions with the NL3 and PK1 effective interactions give slightly better descriptions of reaction observables for exotic neon isotopes. halo, relativistic model, Glauber model, reaction cross section, momentum distribution PACS number(s): 24.10.-i, 25.40.Lw, 24.10.Jv, 24.30.Gd

The cross sections in this work for the 75As (A, N) 78Br reaction were calculated using cross-section equations published in international references for selecting appropriate ground-level reaction energies in a computer program (MATALAB) with energy steps (0.2 MeV). The semi-empirical equation was derived from the tabulated results relating the selected cross-section to the energies. The neutron yield was taken into account according to the Ziegler neutron reaction formula using the (SRIM2013) program. The stopping power was also calculated and plotted by measuring the neutron yield at the specified energies, and the average value over this energy interval can be determined. The values are directly proportional until the alpha energy reaches 25.8 MeV. The neutron yield begins to rise until the alpha energy reaches 25.8 MeV, after which the neutron yield becomes almost constant.

The reduced cross-section method (RCSM) is included in Eurocode 5 (EN-1995-1-2) for the design of timber members in fire conditions. The method considers the strength and stiffness reduction beneath the charred layer by adding an additional depth (known as the ‘zero-strength’ layer) to the charring depth. The zero-strength layer is one of the key parameters for the fire design of timber members. Recently, some concerns have been raised that the zero-strength layer might be non-conservative in some applications. This paper presents the background to the RCSM, followed by a short discussion on the mechanical assumptions, simplifications and possible limitations of the method itself. Further, it discusses determination of the zero-strength layer thickness for members in bending, tension and compression, and provides guidelines on the use of standard experimental tests to determine this quantity. For demonstration of the determination procedure, the results of fire tests in bending, tension and compression were analysed following the described procedure. Results show that the zero-strength layer exceeds the value used in practice, indicate that the method of Eurocode 5 may be non-conservative and should be revised.

This analysis aims to determine photon attenuation for five different ternary and binary iodide compounds using Phy-X/PSD software. For a broad range of photon energies between 0.015 and 15 MeV, the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) for the samples of Cu2HgI4, Ag2HgI4, CuI, AgI, and HgI were calculated. For illustration, the following values of TVL apply at 1 MeV: S1: 6.062 cm, S2: 6.209 cm, S3: 6.929 cm, S4: 6.897 cm, and S5: 4.568 cm. Some important parameters, such as total atomic cross-sections (ACS), electronic cross-sections (ECS), the effective atomic numbers (Zeff), effective electron density (Neff), and effective conductivity (Ceff) of the samples were also calculated. Additionally, exposure buildup factors (EBF) and energy-absorption buildup factor (EABF) were estimated. These data on the radiation characteristics of our samples could be useful for gamma attenuation. The HgI sample has the highest FNRCS values (0.0892) relative to the other tested samples showing good neutron attenuation features. The CuI sample shows low gamma attenuation features; in contrast, it shows high neutron attenuation features.

Accurate radar cross section (RCS) measurements are challenged by background-target coupling, such as interactions with the ground or support structures. This paper introduces a method using three-dimensional (3D) imaging to isolate and measure target scattering characteristics. By utilizing high-resolution 3D imaging algorithms, the method separates the target’s scatterers from background noise, enhancing RCS measurement accuracy. Experimental results show this approach reduces coupling effects, with measurement differences within 0.2 dB, demonstrating its effectiveness.