Search Results (2,857)

Accurate, real-time, and multi-scale soil water content (SWC) monitoring is crucial for understanding terrestrial energy, water, and nutrient cycles. This study assesses the potential of a portable cosmic-ray neutron sensor (CRNS) backpack for measuring SWC in a Mediterranean mountain agroforestry system. Seven field surveys were conducted in northern Spain, covering nine control points under woodland and cropland. CRNS data were compared with in situ SWC measurements from an SM-200 field probe and the NDMI index derived from Sentinel-2 imagery. The results show that the CRNS backpack effectively captures spatial and temporal SWC variations. The CRNS method demonstrated advantages over point-scale sensors by providing integrated measurements at an intermediate scale, while Sentinel-2 data offered valuable insights into moisture variability through vegetation response. The moderate correlations observed among the three methods highlight the complementarity of these approaches for soil moisture monitoring in heterogeneous landscapes. This work underscores the potential of mobile CRNS sensor as a practical tool for field-scale SWC assessment in Mediterranean mountain agroforestry systems, offering new opportunities for cropland and water management in similar landscapes. Full article

Humans are constantly exposed to low doses and low-dose rates of ionizing radiation from both natural and man-made sources. For this reason, there is a growing interest in studies on the biological effects of low-dose radiation. Vibrational spectroscopies, such as Fourier transform infrared and Raman micro-spectroscopies, have been fruitfully employed for studying the effects of high doses of ionizing radiation on biosystems. Aiming at clarifying the potential of the above-mentioned spectroscopic techniques to monitor the changes induced in cells, tissues, and other biological samples by low doses of ionizing radiations, we report a review of the literature in this research field. The analysis of published results suggests that vibrational spectroscopies make a valuable contribution. Additional and more systematic investigations could help to fully exploit the capabilities of these spectroscopic techniques. Full article

This work presents the general mathematical frameworks of the “First and Second-Order Features Adjoint Sensitivity Analysis Methodology for Neural Integral Equations of Volterra Type” designated as the 1st-FASAM-NIE-V and the 2nd-FASAM-NIE-V methodologies, respectively. Using a single large-scale (adjoint) computation, the 1st-FASAM-NIE-V enables the most efficient computation of the exact expressions of all first-order sensitivities of the decoder response to the feature functions and also with respect to the optimal values of the NIE-net’s parameters/weights after the respective NIE-Volterra-net was optimized to represent the underlying physical system. The computation of all second-order sensitivities with respect to the feature functions using the 2nd-FASAM-NIE-V requires as many large-scale computations as there are first-order sensitivities of the decoder response with respect to the feature functions. Subsequently, the second-order sensitivities of the decoder response with respect to the primary model parameters are obtained trivially by applying the “chain-rule of differentiation” to the second-order sensitivities with respect to the feature functions. The application of the 1st-FASAM-NIE-V and the 2nd-FASAM-NIE-V methodologies is illustrated by using a well-known model for neutron slowing down in a homogeneous hydrogenous medium, which yields tractable closed-form exact explicit expressions for all quantities of interest, including the various adjoint sensitivity functions and first- and second-order sensitivities of the decoder response with respect to all feature functions and also primary model parameters. Full article

In one of our previous papers, we obtained a general class of potentials inside the nucleus, such that the singular solution of the Dirac equation for the S-states of hydrogen atoms outside the nucleus can be matched with the corresponding regular solution inside the nucleus (the proton) at the boundary. The experimental charge density distribution inside the proton generates a particular case of such potentials inside the proton. In this way, the existence of the second kind of hydrogen atom was predicted: atoms having only S-states. This theoretical prediction was then evidenced by several different types of atomic experiments and by astrophysical observations. In the present paper we provide the following new results. First, we show that the solution of the Dirac equation inside the proton can be (and is) found within the class of functions that are non-analytic at r = 0—in distinction to the traditional practice of limiting the search for the solution by the class of analytic functions. We demonstrate that this non-analytic solution inside the proton can be matched at the proton boundary R with the corresponding singular solution outside the proton regardless of the particular value of R. Second, we show that the interior and exterior solutions are scale-invariant with respect to the change of the boundary R between these two regions. Such invariance is the manifestation of a new symmetry—in addition to the previously discussed symmetries of the Dirac equation in the literature. Third, based on the new, more accurate results for the wave function inside and outside the proton, we revisit the resolution of the neutron lifetime puzzle initially outlined in our previous papers. On the basis of the more accurate calculations, we reconfirm that (A) the 2-body decay of neutrons produces overwhelmingly the SFHA (rather than the usual hydrogen atoms) and (B) the strengthened-in-this-way branching ratio for the 2-body decay of neutrons (compared to the 3-body decay) is in excellent agreement with the branching ratio required for reconciling the neutron lifetime values measured in the trap and beam experiments, so that the neutron lifetime puzzle seems to be indeed resolved in this way. Full article

Many countries around the world are in a race against time to decarbonise their energy systems. One of the avenues being explored in detail is Offshore Renewable Energy (ORE), with technologies such as wind, wave, and tidal. All of these technologies are in their infancy within the marine environment and required heavy Research and Development (R&D) to make them commercially viable. With so much demand for these industries, the supply chain is heavily constrained. A solution that has shown great potential to alleviate the pressure on the supply chain is the use of Wire Arc Additive Manufacturing (WAAM) for the use of onsite repair or manufacture for components. This is due to its ability to produce large-scale parts, with low emissions and at a lower cost than other Additive Manufacturing (AM) processes. The opportunity to use this technology could result in shorter downtimes and lead to a reduction in the Levelised Cost of Energy (LCOE). However, knowing that offshore structures are subject to cyclic loading conditions during their operational lifespan, fatigue properties of new materials and manufacturing processes must be well documented and studied to avoid any catastrophic failures. An issue often seen with WAAM is the presence of residual stresses. This study looks at fatigue cracking on Compact Tension C(T) specimens that have undergone laser shock peening and rolling, surface treatment processes that form compressive residual stresses at the surface of the material. In this study, the influence of fatigue overloading on the residual stress distribution in surface-treated WAAM specimens is evaluated and the effectiveness of the post-processing techniques on the subsequent fatigue behaviour is explored. Full article

Al 7075 alloy (AA7075) exhibits excellent strength yet poses significant challenges for additive manufacturing (AM) due to its complex composition and propensity for defects during rapid solidification. To address these issues, this study introduces a novel AA7075 containing a small amount of Si fabricated by selective laser melting (SLM). Despite concerns about reduced melt-pool stability at low Si content, the alloy was successfully processed into defect-minimized samples. Systematic evaluations of as-built and heat-treated (direct aging, solid-solution, T6) samples revealed distinct microstructural evolution and clear improvements in mechanical properties and corrosion resistance. Specifically, as-built and direct aging conditions showed high strength but limited ductility and pronounced galvanic corrosion due to inhomogeneous microstructures. Conversely, solid-solution and T6 treatments effectively homogenized the microstructure, significantly enhancing ductility and reducing corrosion susceptibility, with the T6-treated samples exhibiting the most balanced mechanical and electrochemical performance. By maintaining a favorable microstructural balance while minimizing Si-induced brittleness, the low-Si AA7075 demonstrates improved SLM processability and robust performance. These findings offer a new pathway for optimizing AM aluminum alloys through tailored heat treatments. Full article

This paper presents a preliminary investigation into the total dose effects and displacement damage effects on β-Ga₂O₃ Schottky barrier diodes (SBDs) induced by X-rays with an average energy of 8–20 keV and 1 MeV reactor neutrons. The electrical performance of the devices before and after irradiation was evaluated through direct current (I-V) and capacitance–voltage (C-V) measurements. The results indicate that under X-ray irradiation, as the irradiation fluence increases, the forward current density, leakage current, and reverse current density of the devices increase, suggesting a progressive degradation of device performance with higher irradiation fluence. In the case of neutron irradiation, the forward current density decreases, while the leakage current and reverse current density increase with rising irradiation fluence. By employing techniques such as low-frequency noise (LFN) and deep-level transient spectroscopy (DLTS), changes in defect concentrations before and after irradiation were analyzed. It was found that the primary causes of device performance degradation are the interface defects induced by X-ray irradiation and the increased bulk defect concentration caused by neutron irradiation. These findings were further validated through two-dimensional numerical simulations using TCAD tools, providing significant theoretical insights and experimental data to enhance reliability and optimize the design of such devices. Full article

We describe the quark substructure of hadrons and the equation of state of high-density neutron star matter by using the Nambu–Jona-Lasinio (NJL) model, which is an effective quark theory based on QCD. The interaction between quarks fully respects the chiral and flavor symmetries. Guided by the success of various low-energy theorems, we assume that the explicit breaking of these symmetries occurs only via the current quark masses, and all other symmetry breakings are of dynamical nature. In order to take into account the effects of the finite quark core sizes of the baryons on the equation of state, we make use of an excluded volume framework that respects thermodynamic consistency. The effects generated by the swelling quark cores generally act repulsively and lead to an increase in the pressure with increasing baryon density. On the other hand, in neutron star matter, these effects also lead to a decrease in the density window where hyperons appear because it becomes energetically more favorable to convert the faster moving nucleons into hyperons. Our quantitative analysis shows that the net effect of the excluded volume is too small to solve the long-standing “hyperon puzzle”, which is posed by the large observed masses of neutron stars. Thus, the puzzle persists in a relativistic effective quark theory which takes into account the short-range repulsion between baryons caused by their finite and swelling quark core sizes in a phenomenological way. Full article

Archaeal membranes exhibit remarkable stability under extreme environmental conditions, a feature attributed to their unique lipid composition. While it is widely accepted that tetraether lipids confer structural integrity by forming monolayers, the role of bilayer-forming diether lipids in membrane stability remains unclear. Here, we demonstrate that incorporating diethers into archaeal-like lipid assemblies enhances membrane organization and adaptability under thermal stress. Using neutron diffraction, we show that membranes composed of mixed diethers and tetraethers exhibit greater structural order and stability compared to pure lipid systems. Contrary to expectations, monolayer-forming tetraethers alone display increased variability in lamellar spacing under fluctuating temperature and humidity, whereas mixed lipid membranes maintain a consistent architecture. Furthermore, neutron-scattering length density profiles reveal an unexpected density feature at the bilayer midplane, challenging conventional models of archaeal monolayer organization. These findings suggest that molecular diversity of lipid molecules, rather than tetraether dominance, plays a critical role in membrane auto-assembly, stability, and adaptability. Our results provide new insights into archaeal membrane adaptation strategies, with implications for the development of bioinspired, robust synthetic membranes for industrial and biomedical applications. Full article

Background/Objectives: Boron neutron capture therapy (BNCT) is a promising approach for selectively targeting and destroying malignant cells using ¹⁰B isotopes. A significant challenge in BNCT lies in the development of efficient boron delivery systems that ensure adequate boron accumulation within tumor cells. This study aims to synthesize, characterize, and evaluate COSAN-functionalized nanoparticles (NP@I-COSAN) as a potential boron carrier for BNCT. Methods: Hybrid nanoparticles were synthesized by conjugating monoiodinated cobaltabisdicarbollides (I-COSAN) to commercially available acrylic polymer-based nanoparticles. Functionalization and cellular uptake were confirmed through FTIR, TGA, UV-Vis spectroscopy, and TEM/EDX analyses. Biocompatibility was evaluated by assessing cytotoxicity in HeLa cells and C. elegans as an in vivo model. Intracellular boron uptake was quantified using ICP-MS, with results compared to those obtained with 4-borono-L-phenylalanine conjugated to fructose (f-BPA). An in vitro BNCT proof-of-concept assay was also performed to evaluate therapeutic efficacy. Results: NP@I-COSAN demonstrated low cytotoxicity and efficient internalization in cells. ICP-MS analysis revealed stable boron retention, comparable to traditional boron agents. The BNCT assay further showed that NP@I-COSAN was effective in inducing tumor cell apoptosis, even at lower boron concentrations than conventional treatments. Conclusions: These results underscore the potential of NP@I-COSAN as an effective boron delivery system for BNCT, offering a promising strategy to enhance boron accumulation within tumor cells and improve treatment efficacy. Full article

Primary and low-strain creep represents a very important integrity challenge to large, complex structures, like fusion reactors. Here, we develop a predictive empirical primary creep model for 9Cr tempered martensitic steels (TMS), relating the applied stress (σ) to strain (ε), time (t) and temperature (T). The most accurate model is based on the applied σ normalized by the steel’s T-dependent ultimate tensile stress (σ_o), σ/σ_o(T). The model, fit to 17 heats of 9Cr TMS, yielded a σ root mean square error (RMSE) of ≈±11 MPa. Notably, the model also provides robust predictions for all the other TMS, when calibrated only by the fusion candidate Eurofer97 database. The model was extended to explore two possible effects of neutron irradiation, which produces both displacements per atom (dpa) and helium (He in atomic parts per million, appm) damage. These effects, which have not been previously considered, include: (a) softening, as a function of dpa, at T > ≈400–450 °C, in low-He fission environments (<1 He/dpa); and (b) subsequent re-hardening in high-He (≥10 He/dpa) fusion first-wall environments. The irradiation effect models predict (a) accelerated primary creep due to irradiation softening; and (b) fully arrested creep due to high-He re-hardening. Full article

Bacillus anthracis secretes three protein exotoxins: Protective Antigen 83 (PA83), Lethal Factor (LF), and Edema Factor (EF). A cleaved form of PA83 (PA63) aids LF and EF entry into the cytoplasm, which leads to anthrax-induced cell death. The Protein Data Bank (PDB) has more than 25 structures of LF: the monomer alone, bound with inhibitors, or bound to PA63. The structures are all—with only minor shifts of a few Ångströms—nearly congruent. We have measured the structure of LF at equilibrium in D₂O solution by small-angle neutron scattering (SANS). The shape is modeled well by a parallelepiped (all angles 90°) with dimensions of 12 Å × 49 Å × 129 Å. For a protein with a typical density of 1.4, the molecular weight would be between 55 and 94 kDa, which is comparable to that of the 90.2 kDa monomer. However, the LF crystal structure PDB 1pwu (a generally V-shaped molecule with equal arm lengths ≈ 70 Å) with the same model fits the dimensions 30 Å × 48 Å × 104 Å. Given the large changes in the long and short dimensions, straightforward physical modeling of the solution structure from the crystal form is unable to match the SANS results. Full article

The Chinese Chang’E-7 (CE-7) mission is planned to land in the lunar south polar region, and then deploy a mini-flying probe to fly into the cold trap to detect the water ice. The selection of a landing site is crucial for ensuring both a safe landing and the successful achievement of its scientific objectives. This study presents a method for landing site selection in the challenging environment of the lunar south pole, utilizing multi-source remote sensing data. First, the likelihood of water ice in all cold traps within 85°S is assessed and prioritized using neutron spectrometer and hyperspectral data, with the most promising cold traps selected for sampling by CE-7’s mini-flying probe. Slope and illumination data are then used to screen feasible landing sites in the south polar region. Feasible landing sites near cold traps are aggregated into larger landing regions. Finally, high-resolution illumination maps, along with optical and radar images, are employed to refine the selection and identify the optimal landing sites. Six potential landing sites around the de Gerlache crater, an unnamed cold trap at (167.10°E, 88.71°S), Faustini crater, and Shackleton crater are proposed. It would be beneficial for CE-7 to prioritize mapping these sites post-launch using its high-resolution optical camera and radar for further detailed landing site investigation and evaluation. Full article

In this study, the results of transmission electron microscopy (TEM) examinations of neutron-irradiated (2.5 dpa at 150 °C, 350 °C, and 450 °C) CuCrZrV and ODS(Y₂O₃)-Cu alloys are presented. These materials were developed for application as heat sink materials in fusion technology. This study includes TEM imaging and quantitative analysis of neutron radiation-induced defects such as dislocation loops and voids as well as the determination of the conditions for their formation. It was found that dislocation loops of a₀½⟨110⟩ type form in both alloys at all irradiation temperatures. The formation of voids in CuCrZrV alloy is effectively suppressed. The neutron irradiation causes a redistribution of Cr, Zr, and V in the CuCrZrV alloy. A particular focus was on the investigation of the distribution of the transmutation products Ni and Zn. Ni tends to segregate at the Cr-rich clusters and forms a shell around them, while Zn is evenly distributed. Full article

‘Whitestone’ is a characteristic raw material in the Late Neolithic (Tisza and Lengyel culture) polished stone tool (chisel, adze, macehead) archaeological record in Southern Hungary. However, the lithology—the technical term not reflecting a petrographic definition—needs detailed petrographic-analytical investigations (by optical microscopy, PGAA, and SEM-EDS) to determine the exact rock types and to connect them to specific geological sources. This article identifies the main types of ‘whitestone’ and, furthermore, focuses on the predominant ‘silicified magnesite’ type and the secondary ‘silicified limestone/dolomite’ type. Based on our results, both types originated from the alteration of serpentinized ultramafic assemblages, most probably from the closest magnesitic alteration zones of serpentinite outcrops in Serbia. Thus, the most possible provenance of the Late Neolithic ‘whitestone’ polished stone tools is the Serbian magnesite. These lithologies are in the territory of the Late Neolithic Vinča culture, which was engaged in mass production of ‘whitestone’ tools. This fact indicates the strong relationship of that population with the Tisza and Lengyel communities. Full article