Search Results (1,293)

Tree rings, tree needles, and moss can be used as biomonitors to evaluate atmospheric pollutant concentrations and deposition patterns spanning different timescales. This study compares output from air quality modeling and measurements to patterns observed using a combination of sulfur concentration and isotope composition in moss (using moss bags and controls) as biomonitors in a region of southern Alberta, Canada influenced by industrial emissions. Tree rings allow comparisons of historical to current sulfur deposition patterns. Moss, which integrates atmospheric nutrients during growth, allows for concurrent comparisons. The contrast of inorganic and organic sulfur within conifer tree needles provides a measure of pollutant uptake over their short lifespans. Sulfur uptake within biomonitors in a southern Alberta ecosystem allow assessment of the presence (in moss, needles) and effects (on conifer growth) of atmospheric sulfur deposition from industrial emissions. These data were examined relative to California Puff (CALPuff) model projections and traditional active and passive air quality sampling. Patterns in sulfur isotope abundance (δ³⁴S) from moss bags placed throughout the eastern slopes of the southern Alberta foothills of the Rocky Mountains implicate local industry as the dominant atmospheric sulfur source over winter, with the tissues of conifers (needles and cores) and moss decreasing with distance from industrial emissions. This was consistent with apportionment calculations based on active and passive sampling, which also showed a surprising trend of sulfur deposition upwind of the industrial stack in the mountains to the west. δ³⁴S values for pine needles and tree rings were consistent with greater sulfur stress and reductions in tree growth associated with increased industrial sulfur concentrations and deposition. We conclude that plant biomonitors are effective short-term (tree needles and moss) and long-term (tree cores) indicators of sulfur pollution in a complex, mountainous landscape. Full article

Current ringing in dual-active bridge (DAB) converters significantly degrades efficiency and reliability, particularly due to resonant interactions in the magnetic tank impedance network. We propose a novel impedance resonant channel shaping technique to suppress the ringing by systematically modifying the converter’s equivalent impedance model. The method begins with establishing a high-fidelity network representation of the magnetic tank, incorporating transformer parasitics, external inductors, and distributed capacitances, where secondary-side components are referred to the primary via the turns ratio squared. Critical damping is achieved through a rank-one modification of the coupling denominator, which is analytically normalized to a second-order form with explicit expressions for resonant frequency and damping ratio. The optimal series–RC damping network parameters are derived as functions of leakage inductance and winding capacitance, enabling precise control over the effective damping factor while accounting for core loss effects. Furthermore, the integrated network with the damping network dynamically shapes the impedance response, thereby attenuating ringing currents without compromising converter dynamics. Experimental validation confirms that the proposed approach reduces peak ringing amplitude by over 60% compared to the conventional snubber-based methods, while maintaining full soft-switching capability. Full article

This review of thiazolidinedione or glitazone, which have a five-membered heterocyclic ring C₃NS, shows their versatile properties in terms of pharmacological actions such as antimicrobial, antifungal, insecticidal, pesticidal, antidiabetic, anti-inflammatory, anti-proliferative, anti-neurotoxicity, anticonvulsant, anti-thyroidal, and anti-tubercular uses. While having a wide range of biological activities, the TZDs mainly act via binding to the peroxisome proliferator-activated receptor (PPAR) members. PPAR-γ are ligand-activated transcription factors, which are members of the nuclear hormone receptors group. Activations of PPAR-γ regulate cell proliferation and differentiation, glucose homeostasis, apoptosis, lipid metabolism, and inflammatory responses. This review explores the synthesis of a thiazolidinedione and its derivatives, focusing on their pharmacological profiles and antidiabetic activity. It highlights the benefits of synthesis, reaction profiles, and catalyst recovery, which may encourage further investigation into these scaffolds by researchers. Based on synthesized derivatives, some glimpses of the structure–activity relationships of some compounds have been compiled. All the synthesized derivatives have been reviewed concerning their standard drugs already available and concluded with the highly or moderately active synthesized derivatives of thiazolidinedione. The data for this review was collected by an extensive review of current scientific literature, including on the synthesis, biological evaluation, SAR, and patents (2015–25). Full article

The “divergence problem” in recent decades is a tendency for trees in high latitudes to lose climate sensitivity. Growth divergence has been reported for certain tree species in alpine or northern latitude locations but has yet to be found in species with southern distributions. This retrospective study used tree ring data collected from longleaf pine trees (Pinus palustris Mill.) in natural stands and a young plantation to test whether divergence exists in this important southeastern tree species. Our results demonstrate that a growth divergence in basal area increment (BAI) occurred among individual longleaf pines within stands. The BAI of each tree followed Taylor’s law but with differing exponents, which varied from 0.75 to 6.4. Divergence of BAI among trees increased with time, and it might be related to the local drought, as the highest BAI divergence occurred when the SPEI (standardized precipitation-evapotranspiration index) was approximately 0 (−0.3–0.3). Hourly dendrometer measurements confirmed growth divergence among individuals. Collectively, our study provides new information about the growth characteristics of longleaf pine, which may partially explain how this species persists and thrives in southeastern environments. Our current management strategy on longleaf pine forests, such as prescribed burning and genetics improvement efforts, needs to be adapted. Full article

Atmospheric plasma spraying was used to create composite coatings employing mixed alloy matrices supplemented with carbon-based solid lubricants as feedstock materials. The current study’s goal was to examine the tribological properties of these coatings and explore the potential benefits of using CNTs as a nano-additive to minimize wear and friction while enhancing lubrication conditions in tribosystems such as piston ring–cylinder liner systems. Pin-on-disk measurements are used to correlate the chemical composition of feedstock materials with the friction coefficient and wear rate during coating operation. The enhanced behavior of the produced coatings is investigated. The anti-wear performance of Co-based cermet and metal alloys coatings, as well as the enhanced lubrication conditions during operation, are shown. In-depth discussion is provided regarding how the features of the feedstock powder affect the quality and performance of the produced coatings. The results showed that coatings based on the CoMo alloy exhibited an increase in wear due to CNT agglomeration. In contrast, CNT addition led to an improvement in bonding strength by up to 33%, a reduction in wear rate by up to 80%, and a decrease in the coefficient of friction from approximately 0.70 to 0.35 in CoNi cermet coatings. These findings demonstrate the role of CNTs in coating performance for demanding tribological applications. Full article

A bias-free antenna tuning technique that eliminates conventional DC biasing networks is presented. The tuning mechanism is based on a Light-Dependent Resistor (LDR) embedded within the antenna structure. Optical illumination is used to modulate the LDR’s resistance, thereby altering the antenna’s effective electrical length and enabling tuning of its resonant frequency and operating bands. By removing the need for bias lines, RF chokes, blocking capacitors, and control circuitry, the proposed approach minimizes parasitic effects, losses, biasing energy, and routing complexity. This makes it particularly suitable for compact and energy-constrained platforms, such as Internet of Things (IoT) devices. As proof of concept, an LDR is integrated into a ring monopole antenna, achieving tri-band operation in both high and low resistance states. In the high-resistance (OFF) state, the fabricated prototype operates across 2.1–3.1 GHz, 3.5–4 GHz, and 5–7 GHz. In the low-resistance (ON) state, the LDR bridges the two arcs of the monopole, extending the current path and shifting the lowest band to 1.36–2.35 GHz, with only minor changes to the mid and upper bands. The antenna maintains linear polarization across all bands and switching states, with measured gains reaching up to 5.3 dBi. Owing to its compact, bias-free, and low-cost architecture, the proposed design is well-suited for integration into portable wireless devices, low-power IoT nodes, and rapidly deployable communications systems where electrical biasing is impractical. Full article

The working environment of carbon brushes and slip rings in marine applications is extremely harsh, as salt spray deposition alters the contact surface and significantly affects contact resistance. To accurately evaluate the electrical contact performance of carbon brushes and slip rings, it is essential to establish a mathematical model of contact resistance. The main influencing factors include salt spray concentration, sliding speed, contact current, and contact pressure. In this study, the variation trends of dynamic contact resistance with respect to these four factors were investigated through experiments, and the corresponding mechanisms were analyzed. The results show that contact resistance increases consistently with rising salt spray concentration, and the trend continues upward. It also increases gradually with higher sliding speed. Conversely, contact resistance decreases gradually as contact pressure increases. Similarly, an increase in contact current leads to a gradual decrease in contact resistance. Based on the experimental results, a sliding electrical contact resistance (ECR) model incorporating salt spray concentration, sliding speed, contact current, and contact pressure was developed. The findings confirm that the proposed model can be used to predict sliding ECR under various marine working conditions. Full article

Background/Objectives: Amyotrophic Lateral Sclerosis (ALS) is a progressive and fatal neurodegenerative disease characterized by motor neuron loss, muscle weakness, and respiratory dysfunction, often culminating in ventilatory failure. Evidence suggests that High-Definition Transcranial Direct Current Stimulation (HD-tDCS) may modulate motor cortical excitability and potentially influence motor and respiratory function in ALS. This study aims to evaluate the effects of home-based HD-tDCS applied over the primary diaphragmatic motor cortex on respiratory parameters and disease progression in individuals with ALS. Methods: This is a multicenter, randomized, controlled clinical trial. Eligible participants (aged 18–80, both sexes, diagnosed with ALS) will be randomized into an active HD-tDCS group (gTDCS) or a sham group (gSham). The intervention consists of 30 min daily HD-tDCS sessions (3 mA) applied for two weeks (5 days/week), using a 4 × 1 ring configuration targeting the diaphragmatic motor cortex. Sham stimulation includes an identical setup but only delivers ramp currents (30 s) with a minimal ongoing current (0.1 mA). Results: Pre-, intra-, and post-intervention evaluations will include measures of cortical excitability, cerebral and tissue perfusion, surface electromyography, respiratory and pulmonary function, fatigue, sleep quality, pain, motor performance, dyspnea, quality of life, and adverse effects. All procedures will be conducted at participants’ homes with appropriate safety monitoring. Conclusions: This study will investigate the effects of HD-tDCS on respiratory and motor function in ALS and explore the feasibility of a home-based neuromodulation intervention. The outcomes may provide insight into non-pharmacological strategies for respiratory management in ALS. Full article

Amitriptyline (AMT), a widely prescribed antidepressant, and its metabolites have emerged as significant environmental contaminants, posing substantial risks to aquatic organisms and human health. Systematic and in-depth investigations into advanced anode materials, coupled with a profound elucidation of their electrochemical mechanisms, are imperative for the development of efficacious technologies for AMT removal. In this study, a series of amorphous carbon-encapsulated zinc oxide (C@ZnO) modified anodes were systematically synthesized and incorporated into a persulfate-based electrochemical system (CZ-PS) to comprehensively elucidate the catalytic mechanisms and mass transfer efficiencies governing the degradation of AMT via electroperoxidation. Notably, the CZ-PS system achieved a 97.5% degradation for 5.0 mg/L AMT within 120 min under optimized conditions (200 C@ZnO electrode, pH 7.0, current density 20 mA/cm², PS concentration 0.5 mM), significantly outperforming the single PS system (37.8%) or the pure electrocatalytic system. Quenching experiments and EPR analysis confirmed hydroxyl radicals (•OH) and sulfate radicals (SO₄•⁻) as the dominant reactive species. Both acidic and neutral pH conditions were demonstrated to favorably enhance the electrocatalytic degradation efficiency by improving adsorption performance and inhibiting •OH decomposition. The system retained >90% degradation efficiency after 5 electrode cycles. Three degradation pathways and 13 intermediates were identified via UPLC–MS/MS analysis, including side-chain demethylation and oxidative ring-opening of the seven-membered ring to form aldehyde/carboxylic acid compounds, ultimately mineralizing into CO₂ and H₂O. It demonstrates strong engineering potential and provides a green, high-efficiency strategy for antibiotic wastewater treatment. Full article

With the ongoing advancement of triboelectric nanogenerator (TENG) technology, a novel internal integrated monitoring sensor has been introduced for traditional industrial equipment. A multilayer triboelectric material deep groove ball triboelectric nanogenerator (DGTG) device has been proposed to monitor the rotational speed and slip state of the rolling elements. The DGTG utilizes a copper inner ring charge supplementation mechanism to maintain the maximum charge density on the rolling element, thereby ensuring a strong electrical signal output. The deviation between the output frequency of the electrical signal and the theoretical value allows for effective monitoring of the slip state during bearing operation. Experimental results demonstrate that when the inner ring speed ranges from 100 to 2000 rpm, the open-circuit voltage generally remains above 30 V. The short-circuit current signal exhibits a fitting coefficient of R² = 0.99997 with respect to the roller’s rotational speed frequency and motor speed, while the open-circuit voltage signal shows a fitting coefficient of R² = 0.99984, indicating a strong linear relationship and a good response to varying speeds. Compared to the traditional photoelectric sensors commonly used in industry, the measurement difference between the three signals is consistently less than 5.5%, and real-time monitoring of the slip rate is possible when compared to the theoretical value. The DGTG developed in this study occupies minimal space, offers high reliability, and fully leverages the bearing structure, enabling real-time monitoring of bearing speed and slip. Full article

The fabrication of plasmonic nanostructures with precise geometries and scalable production remains a critical challenge for advancing light–matter interaction technologies in applications such as sensing, photonics, and thermal management. Here, we present a versatile, self-assembly-based strategy for metallic nanoring fabrication. We extend Hole-mask Colloidal Lithography (HCL) by employing ring-shaped holes to produce nanorings via direct current (DC) magnetron sputtering. The process relies entirely on industry-standard thin-film techniques, enabling wafer-scale integration. Using this approach, we fabricate copper (Cu) nanorings with tunable near-infrared (NIR) resonances suitable for thermoplasmonic applications. The thermoplasmonic performance of these nanorings is evaluated under direct sunlight, revealing efficient photon-to-heat conversion. Nanorings displayed enhanced heating, outperforming nanodisks of equivalent size, with maximum surface temperatures reaching approximately 37 °C, an increase of over 13 °C above ambient, in contrast to the 6 °C increase shown by disks that reached a temperature of 30 °C. This superior performance is attributed to the nanoring geometry, which promotes stronger light absorption and localized heating. Overall, our results demonstrate that Cu nanorings represent a robust and scalable plasmonic platform with significant potential for solar-driven technologies and thermal management applications. Full article

A ring-oscillator based voltage-controlled oscillator (VCO) architecture with reduced frequency drift across temperature and process variations is presented in this paper. The frequency stability is achieved through two dedicated compensation techniques: a temperature compensation circuit that generates a proportional-to-absolute-temperature (PTAT) current to mitigate frequency shifts due to temperature changes, and a process compensation circuit that dynamically adjusts the frequency based on detected process corners. The proposed design is implemented in a 22 nm CMOS technology with a 0.8 V supply voltage and targets a nominal oscillation frequency of 2.5 GHz. The post-layout simulation results demonstrate a significant improvement in frequency stability, reducing temperature-induced frequency drift from 23.9% to a range of 5.4% over the −40 °C to 125 °C temperature range for the typical corner. Combining temperature and process compensation, the frequency drift is improved from 47.3% to better than 7.2%. The VCO also achieves a phase noise value about −80 dBc/Hz at a 1 MHz offset with an average power consumption of 380 µW, including the tuning mechanism and the compensation circuits. Full article

During the detailed design of magnets for the storage ring of Siam Photon Source II (SPS-II), the influence of magnetic crosstalk between adjacent magnets in the compact Double Triple Bend Achromat (DTBA) lattice was investigated. Using Opera-3D magnetostatic simulation, six magnet pairs were analyzed to investigate the changes in magnetic field distribution along the electron trajectory and integrated magnetic field within each magnet aperture. The study employed polynomial and Fourier analyses to calculate multipole field components. Results indicate that magnetic crosstalk affects the field distribution in the region between magnets, particularly for the defocusing quadrupole and dipole magnets (QD2-D01) and the focusing quadrupole and octupole magnets (QF42-OF1) pairs, which have the pole-to-pole distances of 153.37 mm and 116.45 mm, respectively. Although these separations exceed the estimated fringe field regions, deviations of up to 1% in the main field components were observed. Notably, even an unpowered neighboring magnet contributes to magnetic field distortion due to the modified magnetic flux distribution. Crosstalk effects on the higher-order multipole fields are mostly within the acceptable limit, except for the extra quadrupole field from QD2 found in the dipole D01 magnet. This study highlights the effects of magnetic interference in tightly packed lattice and underscores the need to include a complete multipole field data with crosstalk consideration in the SPS-II lattice model in order to ensure an accurate beam dynamics simulation and predict the operating current adjustments for machine commissioning. Full article

Extensive radar investigations, observed spectral signatures, geomorphological, and paleoclimate modeling support the presence of mid- to low-latitude ground ice on Mars. The presence of near-surface ice and glacial features has been proposed in Ismenius Lacus, but the ice composition and age remain unconstrained. Our high-resolution stereoscopic analysis reveals distinctive landforms, including sharp-edged polyhedra, chevron patterns, and en-echelon open fractures, indicative of plastic glacial deformation. Current climatic conditions may support year-round ice stability, while sharp-edged polyhedra, open fractures, and the absence of superposed craters suggest active glaciation. The Ariguani delta system lacks fluvial signatures but aligns with glacial erosional and depositional processes. Unlike terrestrial glaciers, ice accumulation here is likely driven by escarpment-fed melt from seasonal permafrost thawing under lithostatic pressure, generating neo-glacial flows that sustain the glacial tongue. This mechanism can also explain regional features, including U-shaped valley subsidence, gravitational slides, flow of low-viscosity material lobes, and ring-mold craters. Thus, we propose sharp-edged polyhedra as diagnostic markers for identifying ongoing ice dynamics on Mars, enabling future automated detection of active glacial environments. Full article

We theoretically investigate high-order harmonic generation from ethylbenzene (C₈H₁₀), toluene (C₇H₈), and benzene (C₆H₆) molecules driven by a circularly polarized laser field using time-dependent density functional theory. By comparing the harmonic spectra of these structurally related molecules, we find that ethylbenzene, which features a larger molecular size due to the ethyl group, exhibits a higher harmonic cutoff and stronger harmonic intensity than toluene and benzene. Time-resolved electron density distributions, together with the probability current density analysis, indicate that under long-wavelength conditions (e.g., 1200 nm), the ethyl group in ethylbenzene and the methyl group in toluene significantly enhance the probability of ionized electrons from neighboring nuclei colliding with nearby nuclei, thereby leading to stronger harmonic emission, with ethylbenzene > toluene > benzene. In contrast, under short-wavelength conditions (e.g., 200 nm), the harmonic intensities of the three molecules show little difference, and the effects of the ethyl and methyl groups on the harmonic yield can be neglected. The influence of laser intensity and wavelength on high-order harmonic generation is further analyzed, confirming the robustness of the structural enhancement effect. Additionally, we study the harmonic ellipticity of ethylbenzene under different carrier-envelope phases, and find that while circularly polarized harmonics can be obtained, their spectral continuity is insufficient for synthesizing isolated circularly polarized attosecond pulses. This limitation is attributed to the broken ring symmetry caused by the ethyl substitution. Our findings offer insight into the relationship between molecular structure and harmonic response in strong-field physics, and provide a pathway for designing efficient circularly polarized attosecond pulse sources. Full article