Values Of Cross Sections Research Articles

Meso-β, β-β' trifused porphyrins: synthesis, spectral, electrochemical and DFT studies and their femtosecond third-order nonlinear optical properties.

Meso-β, β-β' trifused porphyrins incorporating two distinct active methylene groups (MN = malononitrile and IND = 1,3-indanedione) and their corresponding metal complexes with Cu(II) and Zn(II) have been synthesized with good to excellent yields and characterized by various spectroscopic techniques and spectrometric methods. Single crystal X-ray analysis of the Zn(II) complex ZnTFPMB(MN)2 (where TFP = trifused porphyrin and MB = mono benzo) revealed a ruffled nonplanar 'armchair' type conformation with a twist angle of 24.10°. The absorption spectra showed a significant bathochromic shift in both the B- and Q-bands, extending into the near-infrared (NIR) region, particularly for π-extended trifused porphyrins. The cyclic voltammograms of MN-appended trifused porphyrins revealed unusual redox behavior, likely due to chemical reactions occurring at the electrode surface during electroreduction. The HOMO-LUMO energy gap for the π-extended porphyrins (MTFPMB(VCN)2) was effectively reduced to ≤1.5 V, compared to ∼2.23 V for the parent porphyrins. Additionally, the femtosecond third-order nonlinear optical properties of the synthesized trifused porphyrins and reported Ni(II) complexes were investigated using the Z-scan technique. Most of the studied porphyrins exhibited promising three-photon absorption coefficients and cross-section values, suggesting their potential applications in optical limiting, bio-imaging, and advanced optoelectronics.

Characterization of Sugammadex-Related Isomeric Cyclodextrin Impurities Using Cyclic Ion Mobility High-Resolution Mass Spectrometry.

Cyclic ion mobility-mass spectrometry (cIM-MS) is a powerful technique for separating and identifying isomeric mixtures of compounds. When coupled with chromatography, cIM-MS creates a multidimensional separation system, with high resolving power and peak capacity. In this study, we report the cyclic ion mobility separation and high-resolution mass spectrometry identification of four regioisomers of a Sugammadex-related impurity, abbreviated as Di-OH-SGM. Separation using multipass cyclic ion mobility was achieved by selecting the [M + 2Na]2+ ion, while other adducts, such as [M + Na]+, [M + 2H]2+, [M + H + Na]2+, and [M - 2H]2- did not yield isomer separation. Two methods were developed for ion mobility separation of the isomers: a conventional multipass method and a slicing method. Isomer assignment was based on the characteristic fragment ions. The collision cross section values (cTWCCSN2) of the resolved cyclodextrin isomers were also determined. Ion mobility separation of structurally different fragment ions was demonstrated. Additionally, by coupling cIM-MS with reversed-phase liquid chromatography (HPLC-cIM-MS), two-dimensional separation of the isomers was achieved. The isomers, separated using HPLC-cIM-MS, were identified with the same approach as with cIM-MS alone, and their elution order provided insights into their relative hydrophobicity.

Measurement of top-quark pair production in association with charm quarks in proton–proton collisions at [formula omitted] TeV with the ATLAS detector

Inclusive cross-sections for top-quark pair production in association with charm quarks are measured with proton–proton collision data at a center-of-mass energy of 13TeV corresponding to an integrated luminosity of 140fb−1, collected with the ATLAS experiment at the LHC between 2015 and 2018. The measurements are performed by requiring one or two charged leptons (electrons and muons), two b-tagged jets, and at least one additional jet in the final state. A custom flavor-tagging algorithm is employed for the simultaneous identification of b-jets and c-jets. In a fiducial phase space that replicates the acceptance of the ATLAS detector, the cross-sections for tt¯+≥2c and tt¯+1c production are measured to be 1.28−0.24+0.27pb and 6.4−0.9+1.0pb, respectively. The measurements are primarily limited by uncertainties in the modeling of inclusive tt¯ and tt¯+bb¯ production, in the calibration of the flavor-tagging algorithm, and by data statistics. Cross-section predictions from various tt¯ simulations are largely consistent with the measured cross-section values, though all underpredict the observed values by 0.5 to 2.0 standard deviations. In a phase-space volume without requirements on the tt¯ decay products and the jet multiplicity, the cross-section ratios of tt¯+≥2c and tt¯+1c to total tt¯+jets production are determined to be (1.23±0.25)% and (8.8±1.3)%.-

Two-photon brightness of NIR-emitting, atomically precise DNA-stabilized silver nanoclusters.

Near-infrared (NIR) emitters with high two-photon absorption (2PA) cross-sections are of interest to enable in vivo imaging in the tissue transparency windows. This study explores the potential of DNA-stabilized silver nanoclusters (Ag N -DNAs) as water-soluble two-photon absorbers. We investigate 2PA of four different atomically precise Ag N -DNA species with far-red to NIR emission and varying nanocluster and ligand compositions. 2PA cross-sections, σ 2, were determined by two-photon excited luminescence (2PEL) technique for a wide wavelength range from 810 to 1400 nm. The Ag N -DNAs exhibited reversed strength of corresponding transitions in the two-photon regime, as compared to one-photon, which further demonstrates the complex photophysics of these emitters. Maximal 2PA cross-section value (∼582 GM) was observed for (DNA)3[Ag21]15+, which is stabilized by 3 DNA oligomers. (DNA)2[Ag16Cl2]8+ presented distinct 2PA behavior from the Ag N -DNAs without chlorido ligands, with a high 2PA of 176 GM at 1050 nm. Our findings support the potential of Ag N -DNAs as NIR-to-NIR two-photon probes that are both excited and emit in the NIR. Their high σ 2 and fluorescence quantum yield values result in superior two-photon brightness on the order of ∼102 GM, significantly higher than water-soluble organic fluorophores.

Mass Spectrometry-Based Non-Targeted Lipidome Analysis and Extraction of Markers for the Authentication of White and Black Truffle Species and Their Origin Determination

The visual authentication of high-value truffles (Tuber magnatum and Tuber melanosporum) is challenging, as they share similar morphological characteristics with other truffle species that have a lower economic value. This similarity complicates accurate identification and increases the risk of substitution or mislabeling, which can affect both market prices and consumer trust. For this reason, the aim of this study was to apply a non-targeted lipidomic approach using ion mobility spectrometry-mass spectrometry to distinguish between white (T. magnatum, Tuber borchii, and Tuber oligospermum) and black truffle species (T. melanosprum, T. aestivum, T. aestivum var. uncinatum, T. brumale, and T. indicum) and to determine the different geographical origins of the two most valuable truffle species (T. melanosporum and T. magnatum). Among several hundred features, 37 and 57 lipids were identified as marker compounds to distinguish white and black truffle species using MS/MS spectra and collision cross section (CCS) values, respectively. Only a few marker compounds were necessary to recognize the differences between white and black truffles. In particular, ceramides, glycerolipids, and phospholipids proved to be particularly suitable for separating the species. In addition, different metabolite profiles were determined for T. melanosporum and T. magnatum depending on their geographical origin. These findings lay the groundwork for a comprehensive quality control framework for fresh truffles, ensuring authenticity, detecting adulteration, and preserving their premium status.

Measurement of the Se78(n,γ)Se79 cross section up to 600 keV at the n_TOF facility at CERN

The Se78(n,γ)Se79 cross section has a high impact on the abundances of Se78 produced during the slow neutron capture process (s process) in massive stars. A measurement of the Se78 radiative neutron capture cross section has been performed at the Neutron Time-of-Flight facility at CERN using a set of liquid scintillation detectors that have been optimized for a low sensitivity to neutrons. We present resonance capture kernels up to 70 keV and cross section from 70 to 600 keV. Maxwellian-averaged cross section (MACS) values were calculated for stellar temperatures between kT=5 and 100 keV, with uncertainties between 4.6% and 5.8%. The new MACS values result in substantial decreases of 20–30% of Se78 abundances produced in the s process in massive stars and AGB stars. Massive stars are now predicted to produce subsolar Se78/Se76 ratios, which is expected since Se76 is an s-only isotope, while solar Se78 abundances have also contributions from other nucleosynthesis processes. Published by the American Physical Society 2024

Identification and Structural Elucidation of Acylsugars in Tomato Leaves Using Liquid Chromatography-Ion Mobility-Tandem Mass Spectrometry (LC-IM-MS/MS).

Leaves of tomato plants contain various glandular trichomes that produce a wide range of metabolic products including acylsugars, which may serve as a defense mechanism against various insect pests. Acylsugars exhibit significant structural diversity, differing in their sugar cores, acylated positions, and type of acyl chains. This work demonstrated a comprehensive approach using multidimensional separation techniques, specifically liquid chromatography-ion mobility-tandem mass spectrometry (LC-IM-MS/MS), for structural characterization, and the discrimination of different tomato plants (one cultivar and five accessions) was demonstrated using tomato leaf extracts; six genotypes from five species of Solanum were represented. As a result, we identified 16 acylsugars through their molecular formulas and annotations using LC and MS analyses. The incorporation of ion mobility (IM) analysis revealed an additional 9 isomeric forms, resulting in a comprehensive total of 25 isomeric acylsugars identified. Furthermore, the experimental collision cross section (CCSexp) values agreed reasonably well with the corresponding predicted values (CCSpred), with an overall estimated error of less than 2%. These findings pave the way for research into how the different structural isomers of acylsugars might influence the self-defense mechanism in plants. Moreover, this work demonstrated that the investigated cultivar and accessions of tomatoes can be distinguished from each other based on their metabolite profile, e.g., acylsugars, with principal component analysis (PCA) and linear discriminant analysis (LDA) statistical models, yielding a prediction rate of 98.3%.

Influence of polarization of hot nuclear matter on the anomaly of surface diffuseness of inter-nuclear potential

The fusion excitation functions for 12 colliding systems with 96 ≤ Z 1 Z 2 ≤ 608 are analyzed using coupled-channel (CC) calculations based on the M3Y double-folding (DF) potential supplemented with a repulsive potential that takes into account the incompressibility of the nuclear matter. We also applied the polarization effects of hot nuclear matter (PEHNM) on the calculations of the bare nucleus–-nucleus interaction potential within the framework of the modified density-dependent Seyler–Blanchard (SB) approach in the T 2 approximation. Our results reveal that we obtain a nice description of the experimental data of different fusion systems when we use the present theoretical approach to calculate the energy-dependent values of the fusion cross sections. In this paper, the influence of the PEHNM on the surface diffuseness parameter of the Woods–Saxon (WS) potential is also studied. In order to reach this goal, we extract the corresponding values of this parameter based on the modified form of the DF potential (M3Y+Repulsion+polarization). We find that the extracted values are located in a range between a = 0.61 and 0.80 fm at different incident energies. It seems that the polarization effects of hot nuclear matter play a key role in describing the abnormally large values of the nuclear potential diffusenesses in the heavy-ion fusion reactions. Additionally, the regular decreasing trend for the diffuseness parameter of the nucleus–nucleus potential with the increase in the bombarding energies is also observed.

Significantly Enhanced Electromagnetic Wave Absorption Performances and Corresponding Mechanism of LaMn1-xFexO3 Perovskites

Improving the performance of LaMnO3 perovskite is essential to make it an efficient and ultra-light electromagnetic wave (EMW) absorbing material. In this work, LaMn1-xFexO3 powders (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized by controlling the doping of Fe3+ ions at the B-site using the citric acid-assisted sol-gel method. The effects of Fe3+ ions doping content on crystal structures, magnetic properties and EMW absorption performances were investigated. The obtained LMFO-4 sample exhibited a minimal reflection loss of -54.99 dB at 13.68 GHz, with an adequate absorption bandwidth (RL < -10 dB) spanning 4.56 GHz (11.6∼16.16 GHz) at a matching layer thickness of 2.0 mm. The exceptional EMW absorption performances could be attributed to the Jahn-Teller effect, the double-exchange interactions and the magnetic interactions of Mn and Fe ions. Furthermore, the Computer Simulation Technology (CST) simulations demonstrated that the Radar Cross Section (RCS) value of LMFO-4 was lower than -25.10 dBm2 across angles ranging from -90° to 90° with a thickness of 2.0 mm, indicating the remarkable radar wave attenuation ability. These insights provided valuable guidance for advancing perovskite-based materials tailored for efficient and ultra-light electromagnetic wave absorption applications.

Rational Molecular Design for Balanced Locally Excited and Charge- Transfer Nature for Two-Photon Absorption Phenomenon and Highly Efficient TADF-Based OLEDs.

The pursuit of highly efficient thermally activated delayed fluorescence (TADF) emitters with two-photon absorption (2PA) character is hampered by the concurrent achievement of a small singlet-triplet energy gap (ΔEST) and high photoluminescence quantum yield (ΦPL). Here, by introducing a terephthalonitrile unit into a sterically crowded donor-π-donor structure, inducing a hybrid electronic excitation character, we designed unique TADF emitters possessing 2PA ability. This rational molecular design was achieved through a main π-conjugated donor-acceptor-donor backbone in line with locally excited feature renders a large oscillator strength and transition dipole moment, maintaining a high 2PA cross-section value. The ancillary N-donor-acceptor-donor with charge transfer character highly balances the TADF phenomenon by minimizing ΔEST. A near-unity ΦPL value with a large radiative decay rate over an order of magnitude higher than the intersystem crossing rate and a high horizontal orientation ratio of 0.95 were simultaneously attained for TPCz2NP. The organic light-emitting diodes fabricated with this material exhibit a high maximum external quantum efficiency of 25.4 % with an elevated 2PA cross-section (σ2) value up to 143 GM at 850 nm. These findings offer a venue for designing high-performance TADF emitters with exceptional performance inclusive of 2PA properties, expanding for future functional material design.

Theoretical Study on One- and Two-Photon Absorption Properties of π-Stacked Multimer Models of Phenalenyl Radicals

Effects of the number of monomers (N) on the two-photon absorption (TPA) properties of π-stacked multimer models consisting of phenalenyl radicals were investigated theoretically. We conducted spectral simulations for the π-stacked N-mer models (N = 2, 4, and 6) with different stacking distances (d1) and their alternation patterns (d2/d1). Excitation energies and transition dipole moments were calculated at the extended multi-configurational quasi-degenerate second-order perturbation theory (XMC-QDPT2) level based on the complete active space self-consistent field (CASSCF) wavefunctions with the active space orbitals constructed from the singly occupied molecular orbitals (SOMOs) of monomers. The TPA cross-section value per dimer unit at the first peak, originating from the electronic transition along the stacking direction, was predicted to increase significantly as the d2/d1 approaches one, as the d1 decreases, and as the N increases from 2 to 6. These tendencies are similar to the calculation results for the static hyperpolarizabilities.

Evaluation and synthesis of perovskite crystals as high-Z sensors for hybrid pixel detectors

High-energy photon imaging experiments are crucial techniques in synchrotron facilities, often employing hybrid pixel detectors for these operations. These detectors combine a photo-sensitive semiconductor component with a pixelated microelectronic Application Specific Integrated Circuit (ASIC) for signal processing and image formation. However, detecting photons above 90 keV poses significant challenges, even for heavy semiconductors, due to lower photoelectric absorption cross-section at this energy range. Nevertheless, lead-based perovskites, such as CsPbBr3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{CsPbBr}}_3$$\\end{document}, are remarkable alternatives as they present excellent cross-section values and noteworthy transport properties, contributing to increased high-energy detection efficiencies. Here, we employ a chemical synthesis route for CsPbBr3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{CsPbBr}}_3$$\\end{document} single-crystals, enabling experimental measurements of carrier mobility of 100.7 cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{cm}}^{2}$$\\end{document}/Vs. We also developed a simulation algorithm to calculate the current pulses generated on pixelated electrodes. Our simulations evaluate CsPbBr3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{CsPbBr}}_3$$\\end{document}’s performance coupled with the latest photon-counter ASIC developed by CERN, the Timepix4. Our findings indicate that CsPbBr3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{CsPbBr}}_3$$\\end{document} crystals require intense applied electric fields, around 1 kV/mm, for accurate signal integration. Furthermore, we observed no correlation between incident energy and induced pulse width. Through microelectronics simulations, we demonstrate that the signal formation behavior of CsPbBr3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{CsPbBr}}_3$$\\end{document} is compatible with Timepix4 ASICs, consequently establishing operational guidelines for employing this promising material as sensors in hybrid pixel detectors.

An Observational Study on Implication of Postoperative Visceral Edema, Assessed by CT Scan, on Complications Following Bowel Resection and Anastomosis, in a Tertiary Care Hospital in Maharashtra, India

Introduction: Surgeries involving bowel resection and anastomosis are quite common. Fluid overload, leading to tissue edema and impaired tissue perfusion, may contribute to anastomotic leak, which is one of the most dreaded complication. Methods: In our current study, CT scan, done on postoperative day-4, was used to assess visceral edema, and its effect on development of complications post bowel anastomosis and increase in value of cross section of body trunk area ≥20% was taken as an independent risk factor of severe complication. Results: Twenty three patients were enrolled in the study, 7 of them developed complications. The most common complication observed was wound infection (Clavein Dindo grade II). Only 2 patients (28.57%) had an increase in CT area &gt;20%. Among patients who developed complications, 33.3% had an increase in CT area and 28.6% did not. Various other factors – preoperative albumin level, timing of surgery, duration of surgery – also lead to development of complications. Statistically, no significant association could be derived between the increase in CT area and development of complications. Conclusion: As per the findings of the current study, higher fluid balance was not reflected by an increase in body surface area on CT Scan. Hence, use of CT scan as a tool to assess visceral edema needs further evaluation.

Conductive Biocomposite Made by Two-Photon Polymerization of Hydrogels Based on BSA and Carbon Nanotubes with Eosin-Y.

Currently, tissue engineering technologies are promising for the restoration of damaged organs and tissues. For regeneration of electrically conductive tissues or neural interfaces, it is necessary to provide electrical conductivity for the transmission of electrophysiological signals. The developed biocomposite structures presented in this article possess such properties. Their composition includes bovine serum albumin (BSA), gelatin, eosin-Y and single-walled carbon nanotubes (SWCNTs). For the first time, a biocomposite structure was formed from the proposed hydrogel using a nanosecond laser, and a two-photon absorption cross section value of 580 GM was achieved. Increased viscosity over 3 mPa∙s and self-focusing with a nonlinear refractive index of 42 × 10-12 cm2/W make it possible to create a biocomposite structure over the entire specified area. The obtained electrical conductivity value was 19 mS∙cm-1, due to the formation of effective electrically conductive networks. For a biocomposite with a concentration of gelatin 3 wt. %, formed by low-energy near-IR pulses, the survival of Neuro 2A nerve tissue cells was confirmed. The obtained results are important for the creation of new tissue engineering structures and neural interfaces from a biopolymer hydrogel based on the organic dye eosin-Y and carbon nanotubes by two-photon polymerization.

Machine Learning Framework for Conotoxin Class and Molecular Target Prediction.

Conotoxins are small and highly potent neurotoxic peptides derived from the venom of marine cone snails which have captured the interest of the scientific community due to their pharmacological potential. These toxins display significant sequence and structure diversity, which results in a wide range of specificities for several different ion channels and receptors. Despite the recognized importance of these compounds, our ability to determine their binding targets and toxicities remains a significant challenge. Predicting the target receptors of conotoxins, based solely on their amino acid sequence, remains a challenge due to the intricate relationships between structure, function, target specificity, and the significant conformational heterogeneity observed in conotoxins with the same primary sequence. We have previously demonstrated that the inclusion of post-translational modifications, collisional cross sections values, and other structural features, when added to the standard primary sequence features, improves the prediction accuracy of conotoxins against non-toxic and other toxic peptides across varied datasets and several different commonly used machine learning classifiers. Here, we present the effects of these features on conotoxin class and molecular target predictions, in particular, predicting conotoxins that bind to nicotinic acetylcholine receptors (nAChRs). We also demonstrate the use of the Synthetic Minority Oversampling Technique (SMOTE)-Tomek in balancing the datasets while simultaneously making the different classes more distinct by reducing the number of ambiguous samples which nearly overlap between the classes. In predicting the alpha, mu, and omega conotoxin classes, the SMOTE-Tomek PCA PLR model, using the combination of the SS and P feature sets establishes the best performance with an overall accuracy (OA) of 95.95%, with an average accuracy (AA) of 93.04%, and an f1 score of 0.959. Using this model, we obtained sensitivities of 98.98%, 89.66%, and 90.48% when predicting alpha, mu, and omega conotoxin classes, respectively. Similarly, in predicting conotoxins that bind to nAChRs, the SMOTE-Tomek PCA SVM model, which used the collisional cross sections (CCSs) and the P feature sets, demonstrated the highest performance with 91.3% OA, 91.32% AA, and an f1 score of 0.9131. The sensitivity when predicting conotoxins that bind to nAChRs is 91.46% with a 91.18% sensitivity when predicting conotoxins that do not bind to nAChRs.

Wave absorption and mechanical properties of SiCf-SiO2f/SiC based on a Jaumann structure

The demand for materials with microwave absorption and mechanical properties in high-temperature harsh environments is increasing in military and civil applications, but their availability is limited. In this study, we present a SiCf-SiO2f/SiC based on a Jaumann structure, where quartz fibers serve as the dielectric layer and SiC fibers act as the lossy layer, with alternating stacking of these two types of fibers. The composite exhibits remarkable characteristics including low density (2.1 g/cm3), high strength (flexural strength of 378 MPa), and temperature insensitivity (reflection coefficient (RC) remains below -7 dB from 25°C to 600°C). Acoustic Emission (AE) monitoring was conducted to evaluate the damage before and after oxidation at 1100°C. Our findings indicate that failure prior to oxidation primarily occurs due to microcracks penetrating into the quartz fibers and crystallization of these fibers, while failure after oxidation mainly arises from BN interface failure. Additionally, both the real and imaginary components of the dielectric constants increase along with reflection coefficients from 25°C to 600°C for SiCf-SiO2f/SiC. The analysis of RC based on different thicknesses demonstrates that the SiCf-SiO2f/SiC can still ensure an RC value below -7dB in X-band. The simulated Radar Cross Section (RCS) values remain unchanged within the temperature range of 25°C-600°C, indicating the temperature insensitivity property possessed by these composites.

Flexible CoNiZn@Ti3CNTx MXene@carbon fabrics with hierarchical structure for efficient electromagnetic wave absorption

The widespread application of 5G technology has significantly exacerbated concerns regarding electromagnetic radiation. However, the rigidity and lack of flexibility of traditional electromagnetic wave (EMW) absorption materials make them ill-suited for protecting humans and certain specialized, complex shapes of equipment. Therefore, there is an increasing urgency to develop flexible EMW absorbing fabrics to effectively mitigate electromagnetic pollution. In this study, hierarchical structure CoNiZn@Ti3CNTx MXene@carbon fabrics (CoNiZn@Ti3CNTx@CF) were constructed from nano-flower structure CoNiZn-MOF, Ti3CNTx MXene and fabrics by self-assembly, in-situ growth and pyrolysis. The carbon fabric acts as a skeleton to form a 3D interconnected conductive network, in which loaded nano-flower structure CoNiZn@Ti3CNTx MXene (CoNiZn@Ti3CNTx@C) composites exists excellent dielectric loss and magnetic loss, so that EMW enters the fabric and optimizes the impedance matching, increasing the multiple reflection and scattering of EMW, thereby effectively attenuating EMW. The minimum reflection loss (RLmin) of CoNiZn@Ti3CNTx@CF reaches -44.51 dB at 14.88 GHz with filling ratio of 15 % and thickness of 1.50 mm and the effective absorption bandwidth (EAB) of CoNiZn@Ti3CNTx@CF reaches 4.32 GHz (13.04–17.36 GHz) at 1.55 mm. The EAB of CoNiZn@Ti3CNTx@CF is expanded to 14.56 GHz (3.44–18.00 GHz) through thickness adjustment (1–5.50 mm), covering most of the S, C, X, and Ku bands. The radar cross-section (RCS) value of CoNiZn@Ti3CNTx@CF is 17.3 dB m2 lower than the perfect electrical conductor (PEC), which effectively reduces the probability of the target being detected by the radar detector. This work provides ideas for design and development of flexible EMW absorbing materials.

A Novel Method for the Estimation of Sea Surface Wind Speed from SAR Imagery

Wind is one of the important environmental factors influencing marine target detection as it is the source of sea clutter and also affects target motion and drift. The accurate estimation of wind speed is crucial for developing an efficient machine learning (ML) model for target detection. For example, high wind speeds make it more likely to mistakenly detect clutter as a marine target. This paper presents a novel approach for the estimation of sea surface wind speed (SSWS) and direction utilizing satellite imagery through innovative ML algorithms. Unlike existing methods, our proposed technique does not require wind direction information and normalized radar cross-section (NRCS) values and therefore can be used for a wide range of satellite images when the initial calibrated data are not available. In the proposed method, we extract features from co-polarized (HH) and cross-polarized (HV) satellite images and then fuse advanced regression techniques with SSWS estimation. The comparison between the proposed model and three well-known C-band models (CMODs)—CMOD-IFR2, CMOD5N, and CMOD7—further indicates the superior performance of the proposed model. The proposed model achieved the lowest Root Mean Squared Error (RMSE) and Mean Absolute Error (MAE), with values of 0.97 m/s and 0.62 m/s for calibrated images, and 1.37 and 0.97 for uncalibrated images, respectively, on the RCM dataset.

Implementation of a semi-automatic approach for detection and extraction of oil slicks using Sentinel-1: Case study of the Moroccan exclusive economic zone

Due to its strategic geographic location, Morocco experiences heavy ship traffic, which inevitably has consequences. Ship accidents and illegal discharges, commonly referred to as oil spills, are frequent and pose significant harm to the marine ecosystem. Therefore, employing new technologies, such as satellite monitoring, is crucial and will greatly enhance the ability to monitor and assess these oil spills. The present work is based on Sentinel-1 SAR images and aims to take into evidence the extent of the hydrocarbon marine pollution in all of the Moroccan EEZ. More than 220 possible cases were detected and mapped during the last decade (2014–2024). A batch process was developed to automate the detection of oil spills by identifying areas with reduced Normalized Radar Cross Section (NRCS) values. This process incorporates corrections, masks, wind field estimation, and oil clustering. The method successfully detected approximately 80% of the cases between Kenitra and Casablanca. The closest detected spill is located 1 km from the coast, the largest spill covers an area of 90 km2, and the most extended spill measures about 145 km. This study can help raise awareness among governmental authorities about potential environmental damage and can be used to train artificial intelligence models, which could simulate oil slick propagation.

A comprehensive study of radiation shielding parameters of chalcogens-rich quaternary alloys for nuclear waste management

The current study examines the impact of metal additives on the shielding characteristics of Se76Te20Sn2M2 (where M = Ge, In, Sb, and Pb). These glasses are useful as shielding materials against high-energy radiation, such as X-rays and ϒ-rays, because these glasses have better values of shielding parameters compared to other potential candidates in the race for nuclear safety applications. To this end, we have calculated various radiation-related protection parameters using an online application called Phy-X/PSD. Using this program, we have estimated a complete list of radiation shielding parameters. The impact of the fourth element M (M = Ge, In, Sb, and Pb) on these parameters is also discussed.The maximum mass attenuation coefficient (MAC) was recorded at a photon energy of 15 keV for the incorporation of lead. Half-value layer (HVL) values peaked at 6 MeV and it attained its maximum value for germanium. The highest and lowest values of the linear attenuation coefficients (LAC) were obtained for Se76Te20Sn2Pb2 and Se76Te20Sn2Ge2 alloys respectively. Notably, the Se76Te20Sn2Pb2 alloy exhibited the highest values of effective atomic number (Zeff), electron density (Neff), atomic cross-section (ACS), and electronic cross-section (ECS), indicating superior shielding performance. Conversely, energy absorption buildup factors (EABF) and exposure buildup factors (EBF) were highest for Se76Te20Sn2Ge2 alloy. Neutron attenuation was most effective in the Se76Te20Sn2In2 and Se76Te20Sn2Pb2 compositions. Overall, the incorporation of lead in the parent glass demonstrated superior shielding capability compared to the other compositions studied.