Search Results (842)

Blazars are a class of active galactic nuclei characterized by having one of their relativistic jets oriented close to our line of sight. Their broad emission spectrum makes them exceptional laboratories for probing fundamental physics. In this review, we explore the potential impact on blazar observations of three scenarios beyond the standard paradigm: (i) the hadron beam model, (ii) the interaction of photons with axion-like particles (ALPs), and (iii) Lorentz invariance violation. We focus on the very-high-energy spectral features these scenarios induce in the blazars Markarian 501 and 1ES 0229+200, making them ideal targets for testing such effects. Additionally, we examine ALP-induced effects on the polarization of UV-X-ray and high-energy photons from the blazar OJ 287. The unique signatures produced by these models are accessible to current and upcoming instruments—such as the ASTRI Mini Array, CTAO, LHAASO, IXPE, COSI, and AMEGO—offering new opportunities to probe and constrain fundamental physics through blazar observations. Full article

Human T-cell leukemia virus type 1 (HTLV-1), the first identified human retrovirus, is associated with adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The lack of effective antiviral therapies or vaccines highlights the critical importance of early diagnosis in managing HTLV-1-associated diseases. However, current commercial immunoassays, including enzyme immunoassays, line immunoassays, particle agglutination tests, and Western blots, are often limited by the need for specialized equipment and high costs, which restrict their accessibility in resource-poor regions. To address these challenges, we developed a novel dot-blot immunoassay using HTLV-1 P19 and GP46 synthetic peptides in combination with a precipitating tetramethylbenzidine (TMB) substrate. This innovative approach enables instrument-free visual detection through the formation of distinct blue-brown precipitates. Validation of this immunoassay with 179 clinical serum samples demonstrated 100% specificity and 91% sensitivity. Our assay offers a simple, cost-effective, and field-applicable diagnostic solution for HTLV-1 screening in resource-limited settings, potentially enhancing global surveillance of this neglected pathogen. Full article

An increase in the production of cationic dyes is expected over the next decade, which will have an impact on health and the environment. This work reports an adsorbent hydrogel composed of poly(acrylic acid) [poly(AA)] and Fe₃O₄ particles, prepared by radical polymerization and in situ co-precipitation of Fe³⁺ and Fe²⁺. This Fe₃O₄/poly(AA) composite hydrogel was used to evaluate its potential for removing the cationic dyes methylene blue (MB) and crystal violet (CV) from aqueous solutions. Instrumental characterization of the hydrogel was performed by FTIR, XRD, TGA, VSM, and physicochemical analysis (swelling and response to changes in pH). The results show that the incorporation of Fe₃O₄ particles improves the adsorption capacity of MB and CV dyes to a maximum adsorption of 571 and 321 mg/g, respectively, under the best conditions (pH 6.8, dose 1 g/L, time 24 h). The adsorption data best fit the pseudo-first order (PFO) kinetic model and the Freundlich isothermal model, indicating mass transfer via internal and/or external diffusion and active sites with different adsorption potentials. Moreover, the thermodynamic analysis confirmed that the adsorption process was spontaneous and exothermic, with physisorption as the dominant mechanism. In addition, the Fe₃O₄/poly(AA) hydrogel is capable of removing 95% of the dyes after ten consecutive adsorption–desorption cycles, demonstrating the potential of hydrogels loaded with Fe₃O₄ particles for the treatment of wastewater contaminated with dyes. Full article

Dark matter dominates the matter content of the Universe, yet its particle nature remains elusive. Among the promising multi-messenger astronomy dark matter candidates are weakly interacting massive particles and superheavy dark matter, both of which may manifest themselves in cosmic ray, $\gamma$-ray, and neutrino signatures through annihilation or decay. Here, we explore potential multi-messenger signals from these candidates in galaxy clusters of the Shapley Supercluster—one of the most massive known structures in the local Universe (located at a distance of ∼200 Mpc and containing over ${10}^{16}{M}_{\odot }$ of dark matter). Using the CLUMPY code, we model $\gamma$-ray and neutrino fluxes for weakly interacting massive particle masses between 0.1 and 100 TeV across various final states, comparing the predictions with the sensitivities of current and forthcoming observatories, including CTAO, IceCube, and KM3NeT. For superheavy dark matter scenarios with masses from ${10}^{19}$ to ${10}^{28}$ eV, we employ HDMSpectra code to compute ultra-high-energy cosmic ray proton and neutrino fluxes in the ranges available for observations using present (Pierre Auger Observatory, IceCube, KM3NeT) and future (GRAND, GCOS, etc.) instruments. Full article

The volumetric Hirst method is considered a golden standard in aerobiology for determining particle number concentrations of bioaerosols. Using Hirst-type pollen and spore traps on mobile platforms (i.e., aircraft, cars, motorbikes, bicycles or carried by pedestrians) is anticipated to significantly enhance the spatial and temporal granularity of data for bioaerosol monitoring. Mobile sampling promises to enhance our understanding of bioaerosol dynamics, ecological interactions and the impact of human activities on airborne biological particles. In this article, we present the design and test of an airborne Hirst-type volumetric sampler. We followed a structured approach and incorporated the fundamental principles of the original design, while optimizing for size, weight, power and cost. Our portable Hirst-type volumetric sampler (FlyHirst) was attached to an ultralight aircraft, together with complementing instrumentation, and was tested for collection of atmospheric concentrations of pollen, fungal spores and hyphae. By linking the temporal resolution of the samples with the spatial position of the aircraft, using flight time, we calculated the spatial resolution of our measurements in 3D. In six summer flights over Denmark, our study revealed that the diversity of the recorded spores corresponded to the seasonal expectance. Urtica pollen was recorded up to 1300 m above ground (a.g.l.), and fungal spores up to 2100 m a.g.l. We suggest that, based on this proof-of-concept, FlyHirst can be applied on other mobile platforms or as a personal sampler. Full article

In this study, we utilized Thermo-Calc software (2023a) to optimize the heat treatment process of martensitic stainless steel 90Cr18MoV through phase diagram calculations. The microhardness of 90Cr18MoV was characterized using a nanoindentation instrument. The microstructural morphology of the samples was analyzed using scanning electron microscopy (SEM). The composition of the samples was characterized through scanning electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). Additionally, laser confocal microscopy (FIB) and transmission electron microscopy (TEM) were employed to characterize the precipitate phase composition and size before and after heat treatment, while also observing the dislocation structure within the samples. The relationship between the quenching temperature and the percentage of residual austenite content in the material was established. The influence of the dislocation structure and precipitate size on the hardness of the samples was investigated. The research findings confirm that the observed secondary hardening phenomenon in tempered samples is attributed to the co-precipitation of two types of carbides, M₂₃C₆ and MC, within the matrix. The study investigated the effects of the tempering temperature and duration on the size of secondary precipitates, indicating that M₂₃C₆ and MC particles with sizes less than or equal to 20 nm contribute to enhancing the matrix, while particles larger than 30 nm lead to a reduction in hardness after tempering. Notably, during the tempering process, M₂₃C₆ precipitated from the matrix nucleates on MC. Full article

This study’s objectives were to evaluate the life cycle of a 2 MW solar power plant in northern Poland and provide suggestions for enhancing this kind of installation’s environmental performance. Eight years of operating data were examined under the assumption that 2000 MWh of energy was produced annually on average. The evaluation took into account two waste management scenarios—landfill and recycling—and was carried out in accordance with the ReCiPe 2016 methodology. Human health and water resource usage had the most environmental effects (7.08 × 10⁵ Pt—landfill), but recycling greatly reduced these effects (−3.08 × 10⁵ Pt). Terrestrial ecosystems were negatively impacted by the turbines’ water consumption (8.94 × 10⁵ Pt—landfill), which was lessened in the recycling scenario. The water and soil environment was greatly impacted by released pollutants, such as zinc and chlorinated hydrocarbons, whose emissions were greatly decreased by material recovery. Particularly detrimental was sulfur dioxide (SO₂), which is the cause of PM 2.5 particle matter, which is dangerous to the public’s health. Recycling has helped to lower these pollutants and enhance the quality of the air. Reducing methane and other greenhouse gas emissions can help reduce CO₂ emissions, which were the most significant factor in the context of climate change (1.91 × 10⁴ Pt—landfilling). Recycling lessened these impacts and decreased the need to acquire virgin raw materials, but landfilling was linked to soil acidification and the depletion of mineral resources. According to the findings, even “green” technology, like photovoltaics, can have detrimental effects on the environment if they are not properly handled at the end of their useful lives. Recycling is turning out to be a crucial instrument for lowering negative effects on the environment, increasing resource efficiency, and safeguarding public health. Full article

The High-Energy Ray Observatory (HERO) is a space-based experiment designed to measure the spectrum and composition of cosmic rays using an ionization calorimeter. The instrument’s effective geometric factor is at least 12 m²·sr for protons and 16 m²·sr or more for nuclei and electrons. Over an exposure period of approximately 5 to 7 years, the mission will enable high-resolution, element-by-element measurements of cosmic ray spectra in the energy range of 10¹² to 10¹⁶ eV per particle. A Monte Carlo simulation of the calorimeter—based on a scintillation detector with and without boron additives—was carried out using the GEANT4 software package. In this study, we examine the impact of boron additives in scintillator materials on energy resolution and their potential for discriminating between electromagnetic and hadronic components of cosmic rays. The primary objectives are to demonstrate that boron does not degrade detector characteristics and that it enables an additional timing-based method for cosmic-ray component rejection. The planned launch of the orbital experiment is scheduled for no earlier than 2029. Full article

This work presents an experimental study of the effect of blade count on the flow field and the radiated noise in a low-speed axial fan with a rotating shroud. A two-component Laser Doppler Velocimetry (LDV) system and Particle Image Velocimetry (PIV) instrumentation have been employed to investigate the flow in the gap region and in front of the rotor blades. Additionally, the fan has been installed in a hemi-anechoic chamber and far-field acoustic measurements have been taken with a microphone mounted on-axis upstream of the rotor to show changes in the spectral features of the radiated noise. The tested rotor is a variable-geometry one that has allowed for studying rotor configurations with different numbers of blades of the same chord and shape, i.e., of the same geometry but different solidity. Rotor pressure rise and flow rate are average quantities that have a relevant effect on the leakage flow. Keeping them fixed while varying solidity allows us to highlight the local effects of circumferential pressure non-uniformity caused by differing blade loading. The results show that, at low solidity, the flow leaving the gap is mainly directed radially outward and follows a longer path before being ingested by the rotor, thus losing strength due to mixing with the main flow. As solidity increases, the flow becomes less radial and is more rapidly ingested by the rotor. In all cases, the sound pressure level spectrum shows marked subharmonic humps and peaks originating from the interaction between the leakage flow and rotor. The departure of such peaks from the blade passing frequency increases with the solidity, while the associated energy increases up to seven blades and then decreases. Full article

Drilling fluid losses into formation voids are among the major issues that lead to increases in the costs and nonproductive time of operations. Lost circulation materials have been widely used to stop or mitigate losses. In most cases, the size of the loss zone is not known, making conventional lost circulation materials unsuitable for plugging the loss zone. In this study, novel temperature-sensitive LCM (TS-LCM) particles composed of diglycidyl ether of bisphenol A (DGEBA) and 4,4′-diaminodiphenyl methane were prepared. It is a thermal-response shape-memory polymer. The molecular structure was analyzed by Fourier transform infrared spectroscopy. The glass transition temperature (T_g) was tested by Different scanning calorimetry (DSC). The shape-memory properties were evaluated by a bend-recovery test instrument. The expansion and mechanical properties of particles were investigated under high temperature and high pressure. Fracture sealing testing apparatus was used to evaluate sealing performance. The mechanism of sealing fracture was discussed. Research results indicated that the T_g of the TS-LCM was 70.24 °C. The shape fixation ratio was more than 99% at room temperature, and the shape recovery ratio was 100% above the T_g. The particle was flaky before activation. It expanded to a cube shape, and the thickness increased when activated. The rate of particle size increase for D90 was more than 60% under 120 °C and 20 MPa. The activated TS-LCM particles had high crush strength. The expansion of the TS-LCM particles could self-adaptively bridge and seal the fracture without knowing the width. The addition of TS-LCM particles could seal the tapered slot with entrance widths of 2 mm, 3 mm and 4 mm without changing the lost circulation material formulation. The developed TS-LCM has good compatibility with local saltwater-based drilling fluid. In field tests in the Yan’an area of the Ordos Basin, 15 shale oil horizontal wells were plugged with excellent results. The equivalent circulating density of drilling fluid leakage increased by an average of 0.35 g/cm³, and the success rate of plugging malignant leakage increased from 32% to 82.5%. The drilling cycle was shortened by an average of 14.3%, and the effect of enhancing the pressure-bearing capacity of the well wall was significant. The prepared TS-LCM could cure fluid loss in a fractured formation efficiently. It has good prospects for promotion. Full article

Particle accelerator laboratories, which enable world-class research across many scientific fields, depend on the magnets used to manipulate their particle beams for successful operation. The community employs various techniques, typically based on Hall probes and induction sensors/coils, to verify the performance of these accelerator magnets. When the transverse access around a magnet is restricted, conventional Hall probe systems cannot be deployed or require significant modification, while moving wire/coil systems tend to provide information only on the magnetic field’s integral. This research builds upon a vibrating wire setup first commissioned to locate the magnetic center of quadrupole magnets. Scans up to the n = 200 wire harmonic (∼10 kHz drive frequency) were measured to reconstruct the magnetic field across a wire strung through a test magnet. New software was developed to systematically process the many frequency response scans needed for a detailed field reconstruction. This research investigated the speed and precision of the measurement, identifying limitations due to both instrumentation and nonlinear wire behavior. The vibrating wire data agreed with a reference Hall probe scan on the order of 6%; roughly 0.7% RMS error persisted after calibrating the vibrating wire data to the reference scan via scaling factor. Full article

Beam diagnostics are essential tools for monitoring the performance of charged particle beams and the safe operation of particle accelerators. The performance of an accelerator is determined by evaluating the properties of beam particles, such as energy, charge, spatial, and temporal density distributions, which require very specific instruments. Faraday Cups (FCs) have emerged as important beam diagnostic devices because of their ability to accurately measure the beam charge and, in some cases, the charge distribution, which can be subsequently used to reconstruct transverse beam profiles. This paper aims to provide a detailed review of FCs, their principles, and their design challenges. FCs have applications in various scientific disciplines that include the measurement of beam current/intensity in particle accelerators, in addition to those for mass spectrometry, beam profiles/total beam currents for broad ion beams, thermonuclear fusion, and antimatter experiments. This review also covers and discusses the versatility of FCs in various scientific disciplines, along with showcasing the technological advancements that include improved collector materials, novel designs, enhanced measurement techniques, and developments in electronics and data acquisition (D.A.Q). A summary of the challenges faced while working with the FCs, such as sensitivity, calibration, and potential errors, is included in this review. Full article

The cyclone separator is a widely used separation instrument that can be applied in dust removal, mist removal, etc. The geometrical parameters that directly affect the airflow and separation process of a cyclone separator play a significant role in operating performance. In the present paper, numerical simulations are conducted to understand the flue gas flow and solid particle motion involved in the separation process of a dust removal cyclone separator. The effects of geometrical parameters on separation efficiency and pressure drop are thoroughly discussed. It is revealed that the separation of flue gas and dust particles depends on the reversible spiral flow arising from the cyclone structure. While the L/D ratio is 1.7, an undesirable flow and particle motion is obtained. As the H/D ratio is increased, the separation efficiency and the separator resistance both drop. In the process, the de/D ratio is increased from 0.6 to 0.7, and flue gas flow becomes worse, resulting in a dramatical descent in separation efficiency and pressure drop. The cut-off particle diameter is about 6 μm, and the particle size has little influence on pressure drop. Full article

This study utilizes Ka-band millimeter-wave cloud radar (MMCR), assisted by a precipitation phenomenon instrument, to conduct case studies and analyses of convective precipitation, cumulus precipitation, and stratus precipitation in the Xi’an region. Using the Doppler spectral data of the MMCR, dynamic parameters such as vertical air motion velocity (updraft and downdraft) and particle terminal fall velocity within these three types of cloud precipitation were retrieved. The results show that above the melting layer, the maximum updraft velocity in convective clouds reaches 15 m·s⁻¹, and the strong updraft drives cloud droplets to move upward at an average velocity of about 5 m·s⁻¹. The average updraft velocity in cumulus clouds is greater than that in stratus clouds, with updrafts in cumulus and stratus mainly distributed within 1.5–3 m·s⁻¹ and 1–2 m·s⁻¹, respectively. The reflectivity factor of precipitation particles (Ze) is used to correct the equivalent reflectivity factor (Ka-Ze) after attenuation correction below the MMCR melting layer. The accuracy of calculating the raindrop concentration using the Ka-Ze of MMCR was improved below the melting layer. Based on the relationship between terminal fall velocity and particle diameter and using the conversion between the MMCR power spectrum and raindrop spectrum, the concentration, fall velocity, and particle diameter of raindrops are calculated below the melting layer. The results show that the average reflectivity factor, average concentration, and average particle diameter of raindrops follow the order of convective precipitation > cumulus precipitation > stratiform precipitation. However, the average terminal fall velocity distribution of raindrop particles follows a different order: convective precipitation > stratiform precipitation > cumulus precipitation. Full article

In the design of operating procedures, structures, and control systems for agricultural machinery and equipment, it is necessary to fully consider data on the properties of relevant agricultural materials as the basis for research and design. Therefore, studying the physical properties of agricultural materials is of great significance. The basic physical parameters of agricultural materials include their shape, size, density, porosity, and moisture content. This study focuses on the triaxial dimensions, 1000-grain weight, moisture content, and tribological properties (sliding friction angle, natural repose angle) of the seeds of 16 varieties of small-seeded vegetables commonly grown in Hainan, including flowering Chinese cabbage, Chinese cabbage, lettuce, and leaf lettuce. Measurements were conducted using instruments such as a digital vernier caliper (Deli, Ningbo, China; accuracy 0.01 mm), an electronic balance (LICHEN, Shanghai, China; accuracy 0.001 g), a constant-temperature oven (Shangyi, Shanghai, China), and self-developed sliding friction angle and natural repose angle testers. Discrete element simulations were performed via EDEM 2021 software to validate the tribological properties by establishing particle models (spherical for flowering Chinese cabbage and Chinese cabbage; long–flat for lettuce and leaf lettuce) and instrument geometric models. Additionally, seed germinability (germination potential, germination rate, and germination speed) was tested using a constant-temperature incubation method. The results showed distinct differences between near-spherical and long–flat seeds in geometric characteristics, 1000-grain weight (2.27–3.06 g vs. 1.00–1.29 g), and tribological behavior (e.g., smaller natural repose angles for near-spherical seeds indicating better flowability). Plastic plates were identified as optimal for seed box guides due to lower sliding friction coefficients. EDEM 2021 simulations effectively verified the experimental data. High-germination-rate seeds (e.g., Hong Kong flowering Chinese cabbage, and Lifeng No.3 Chinese cabbage) were recommended for subsequent trials. These findings provide data support for the selection, design, and optimization of seed rope braiding machine components and sustainable seeding process. Full article